From 8d5930dfb7edbf136f2d9900be34ca7af4ba38c1 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 10 Jul 2020 20:07:10 -0400
Subject: [PATCH 01/19] skb_copy_and_csum_bits(): don't bother with the last
 argument

it's always 0

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/net/ethernet/sun/sunvnet_common.c |  2 +-
 include/linux/skbuff.h                    |  2 +-
 net/core/skbuff.c                         | 11 ++++++-----
 net/ipv4/icmp.c                           |  2 +-
 net/ipv4/ip_output.c                      |  4 ++--
 net/ipv6/icmp.c                           |  4 ++--
 net/ipv6/ip6_output.c                     |  2 +-
 net/sunrpc/socklib.c                      |  2 +-
 8 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/sun/sunvnet_common.c b/drivers/net/ethernet/sun/sunvnet_common.c
index 8dc6c9ff22e1..80fde5f06fce 100644
--- a/drivers/net/ethernet/sun/sunvnet_common.c
+++ b/drivers/net/ethernet/sun/sunvnet_common.c
@@ -1168,7 +1168,7 @@ static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, int ncookies)
 			*(__sum16 *)(skb->data + offset) = 0;
 			csum = skb_copy_and_csum_bits(skb, start,
 						      nskb->data + start,
-						      skb->len - start, 0);
+						      skb->len - start);
 
 			/* add in the header checksums */
 			if (skb->protocol == htons(ETH_P_IP)) {
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 46881d902124..31a6d2fce071 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3535,7 +3535,7 @@ int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
-			      int len, __wsum csum);
+			      int len);
 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
 		    struct pipe_inode_info *pipe, unsigned int len,
 		    unsigned int flags);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 7e2e502ef519..6e806da2913e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2723,19 +2723,20 @@ EXPORT_SYMBOL(skb_checksum);
 /* Both of above in one bottle. */
 
 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
-				    u8 *to, int len, __wsum csum)
+				    u8 *to, int len)
 {
 	int start = skb_headlen(skb);
 	int i, copy = start - offset;
 	struct sk_buff *frag_iter;
 	int pos = 0;
+	__wsum csum = 0;
 
 	/* Copy header. */
 	if (copy > 0) {
 		if (copy > len)
 			copy = len;
 		csum = csum_partial_copy_nocheck(skb->data + offset, to,
-						 copy, csum);
+						 copy, 0);
 		if ((len -= copy) == 0)
 			return csum;
 		offset += copy;
@@ -2791,7 +2792,7 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
 				copy = len;
 			csum2 = skb_copy_and_csum_bits(frag_iter,
 						       offset - start,
-						       to, copy, 0);
+						       to, copy);
 			csum = csum_block_add(csum, csum2, pos);
 			if ((len -= copy) == 0)
 				return csum;
@@ -3011,7 +3012,7 @@ void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
 	csum = 0;
 	if (csstart != skb->len)
 		csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
-					      skb->len - csstart, 0);
+					      skb->len - csstart);
 
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
 		long csstuff = csstart + skb->csum_offset;
@@ -3932,7 +3933,7 @@ normal:
 					skb_copy_and_csum_bits(head_skb, offset,
 							       skb_put(nskb,
 								       len),
-							       len, 0);
+							       len);
 				SKB_GSO_CB(nskb)->csum_start =
 					skb_headroom(nskb) + doffset;
 			} else {
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index cf36f955bfe6..d15f78053ef4 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -352,7 +352,7 @@ static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
 
 	csum = skb_copy_and_csum_bits(icmp_param->skb,
 				      icmp_param->offset + offset,
-				      to, len, 0);
+				      to, len);
 
 	skb->csum = csum_block_add(skb->csum, csum, odd);
 	if (icmp_pointers[icmp_param->data.icmph.type].error)
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 61f802d5350c..5bd059853376 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1126,7 +1126,7 @@ alloc_new_skb:
 			if (fraggap) {
 				skb->csum = skb_copy_and_csum_bits(
 					skb_prev, maxfraglen,
-					data + transhdrlen, fraggap, 0);
+					data + transhdrlen, fraggap);
 				skb_prev->csum = csum_sub(skb_prev->csum,
 							  skb->csum);
 				data += fraggap;
@@ -1411,7 +1411,7 @@ ssize_t	ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 				skb->csum = skb_copy_and_csum_bits(skb_prev,
 								   maxfraglen,
 						    skb_transport_header(skb),
-								   fraggap, 0);
+								   fraggap);
 				skb_prev->csum = csum_sub(skb_prev->csum,
 							  skb->csum);
 				pskb_trim_unique(skb_prev, maxfraglen);
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index a4e4912ad607..83b251151b5c 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -314,10 +314,10 @@ static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, st
 {
 	struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
 	struct sk_buff *org_skb = msg->skb;
-	__wsum csum = 0;
+	__wsum csum;
 
 	csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
-				      to, len, csum);
+				      to, len);
 	skb->csum = csum_block_add(skb->csum, csum, odd);
 	if (!(msg->type & ICMPV6_INFOMSG_MASK))
 		nf_ct_attach(skb, org_skb);
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index c78e67d7747f..2689498157d1 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1615,7 +1615,7 @@ alloc_new_skb:
 			if (fraggap) {
 				skb->csum = skb_copy_and_csum_bits(
 					skb_prev, maxfraglen,
-					data + transhdrlen, fraggap, 0);
+					data + transhdrlen, fraggap);
 				skb_prev->csum = csum_sub(skb_prev->csum,
 							  skb->csum);
 				data += fraggap;
diff --git a/net/sunrpc/socklib.c b/net/sunrpc/socklib.c
index 3fc8af8bb961..d52313af82bc 100644
--- a/net/sunrpc/socklib.c
+++ b/net/sunrpc/socklib.c
@@ -70,7 +70,7 @@ static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to,
 	if (len > desc->count)
 		len = desc->count;
 	pos = desc->offset;
-	csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
+	csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len);
 	desc->csum = csum_block_add(desc->csum, csum2, pos);
 	desc->count -= len;
 	desc->offset += len;

From 3ea7ca80d9c0ff606b5a129dce2354f771a9e4e8 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 10 Jul 2020 20:10:34 -0400
Subject: [PATCH 02/19] icmp_push_reply(): reorder adding the checksum up

do csum_partial_copy_nocheck() on the first fragment, then
add the rest to it.  Equivalent transformation.

That was the only caller of csum_partial_copy_nocheck() that
might pass it non-zero as the last argument.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 net/ipv4/icmp.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index d15f78053ef4..e23dd5fc2e73 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -376,15 +376,15 @@ static void icmp_push_reply(struct icmp_bxm *icmp_param,
 		ip_flush_pending_frames(sk);
 	} else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
 		struct icmphdr *icmph = icmp_hdr(skb);
-		__wsum csum = 0;
+		__wsum csum;
 		struct sk_buff *skb1;
 
+		csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
+						 (char *)icmph,
+						 icmp_param->head_len, 0);
 		skb_queue_walk(&sk->sk_write_queue, skb1) {
 			csum = csum_add(csum, skb1->csum);
 		}
-		csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
-						 (char *)icmph,
-						 icmp_param->head_len, csum);
 		icmph->checksum = csum_fold(csum);
 		skb->ip_summed = CHECKSUM_NONE;
 		ip_push_pending_frames(sk, fl4);

From 6e41c585e38ff696de3a11509a0ad0a11150b0c3 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 22 Jul 2020 22:14:36 -0400
Subject: [PATCH 03/19] unify generic instances of csum_partial_copy_nocheck()

quite a few architectures have the same csum_partial_copy_nocheck() -
simply memcpy() the data and then return the csum of the copy.

hexagon, parisc, ia64, s390, um: explicitly spelled out that way.

arc, arm64, csky, h8300, m68k/nommu, microblaze, mips/GENERIC_CSUM, nds32,
nios2, openrisc, riscv, unicore32: end up picking the same thing spelled
out in lib/checksum.h (with varying amounts of perversions along the way).

everybody else (alpha, arm, c6x, m68k/mmu, mips/!GENERIC_CSUM, powerpc,
sh, sparc, x86, xtensa) have non-generic variants.  For all except c6x
the declaration is in their asm/checksum.h.  c6x uses the wrapper
from asm-generic/checksum.h that would normally lead to the lib/checksum.h
instance, but in case of c6x we end up using an asm function from arch/c6x
instead.

Screw that mess - have architectures with private instances define
_HAVE_ARCH_CSUM_AND_COPY in their asm/checksum.h and have the default
one right in net/checksum.h conditional on _HAVE_ARCH_CSUM_AND_COPY
*not* defined.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/alpha/include/asm/checksum.h   |  1 +
 arch/arm/include/asm/checksum.h     |  1 +
 arch/c6x/include/asm/checksum.h     |  3 +++
 arch/hexagon/include/asm/checksum.h | 11 -----------
 arch/hexagon/lib/checksum.c         | 11 -----------
 arch/ia64/include/asm/checksum.h    |  3 ---
 arch/ia64/lib/csum_partial_copy.c   | 15 ---------------
 arch/m68k/include/asm/checksum.h    |  1 +
 arch/mips/include/asm/checksum.h    |  2 +-
 arch/nios2/include/asm/checksum.h   |  4 ----
 arch/parisc/include/asm/checksum.h  |  8 --------
 arch/parisc/lib/checksum.c          | 17 -----------------
 arch/powerpc/include/asm/checksum.h |  1 +
 arch/s390/include/asm/checksum.h    |  7 -------
 arch/sh/include/asm/checksum_32.h   |  1 +
 arch/sparc/include/asm/checksum.h   |  1 +
 arch/x86/include/asm/checksum.h     |  1 +
 arch/x86/um/asm/checksum.h          | 16 ----------------
 arch/xtensa/include/asm/checksum.h  |  1 +
 include/asm-generic/checksum.h      | 12 ------------
 include/net/checksum.h              |  9 +++++++++
 lib/checksum.c                      | 11 -----------
 22 files changed, 21 insertions(+), 116 deletions(-)

diff --git a/arch/alpha/include/asm/checksum.h b/arch/alpha/include/asm/checksum.h
index 0eac81624d01..7e8e4fa4362d 100644
--- a/arch/alpha/include/asm/checksum.h
+++ b/arch/alpha/include/asm/checksum.h
@@ -42,6 +42,7 @@ extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  * better 64-bit) boundary
  */
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+#define _HAVE_ARCH_CSUM_AND_COPY
 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *errp);
 
 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
diff --git a/arch/arm/include/asm/checksum.h b/arch/arm/include/asm/checksum.h
index ed6073fee338..53f769508540 100644
--- a/arch/arm/include/asm/checksum.h
+++ b/arch/arm/include/asm/checksum.h
@@ -41,6 +41,7 @@ __wsum
 csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr);
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+#define _HAVE_ARCH_CSUM_AND_COPY
 static inline
 __wsum csum_and_copy_from_user (const void __user *src, void *dst,
 				      int len, __wsum sum, int *err_ptr)
diff --git a/arch/c6x/include/asm/checksum.h b/arch/c6x/include/asm/checksum.h
index 36770b8308d9..fa31bdc186b2 100644
--- a/arch/c6x/include/asm/checksum.h
+++ b/arch/c6x/include/asm/checksum.h
@@ -26,6 +26,9 @@ csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
 }
 #define csum_tcpudp_nofold csum_tcpudp_nofold
 
+#define _HAVE_ARCH_CSUM_AND_COPY
+extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+
 #include <asm-generic/checksum.h>
 
 #endif /* _ASM_C6X_CHECKSUM_H */
diff --git a/arch/hexagon/include/asm/checksum.h b/arch/hexagon/include/asm/checksum.h
index a5c42f4614c1..4bc6ad96c4c5 100644
--- a/arch/hexagon/include/asm/checksum.h
+++ b/arch/hexagon/include/asm/checksum.h
@@ -9,17 +9,6 @@
 #define do_csum	do_csum
 unsigned int do_csum(const void *voidptr, int len);
 
-/*
- * the same as csum_partial, but copies from src while it
- * checksums
- *
- * here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-#define csum_partial_copy_nocheck csum_partial_copy_nocheck
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-					int len, __wsum sum);
-
 /*
  * computes the checksum of the TCP/UDP pseudo-header
  * returns a 16-bit checksum, already complemented
diff --git a/arch/hexagon/lib/checksum.c b/arch/hexagon/lib/checksum.c
index c4a6b72d97de..ba50822a0800 100644
--- a/arch/hexagon/lib/checksum.c
+++ b/arch/hexagon/lib/checksum.c
@@ -176,14 +176,3 @@ unsigned int do_csum(const void *voidptr, int len)
 
 	return 0xFFFF & sum0;
 }
-
-/*
- * copy from ds while checksumming, otherwise like csum_partial
- */
-__wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
-{
-	memcpy(dst, src, len);
-	return csum_partial(dst, len, sum);
-}
-EXPORT_SYMBOL(csum_partial_copy_nocheck);
diff --git a/arch/ia64/include/asm/checksum.h b/arch/ia64/include/asm/checksum.h
index 2a1c64629cdc..f3026213aa32 100644
--- a/arch/ia64/include/asm/checksum.h
+++ b/arch/ia64/include/asm/checksum.h
@@ -37,9 +37,6 @@ extern __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
-extern __wsum csum_partial_copy_nocheck(const void *src, void *dst,
-					       int len, __wsum sum);
-
 /*
  * This routine is used for miscellaneous IP-like checksums, mainly in
  * icmp.c
diff --git a/arch/ia64/lib/csum_partial_copy.c b/arch/ia64/lib/csum_partial_copy.c
index 6e82e0be8040..917e3138b277 100644
--- a/arch/ia64/lib/csum_partial_copy.c
+++ b/arch/ia64/lib/csum_partial_copy.c
@@ -96,18 +96,3 @@ unsigned long do_csum_c(const unsigned char * buff, int len, unsigned int psum)
 out:
 	return result;
 }
-
-/*
- * XXX Fixme
- *
- * This is very ugly but temporary. THIS NEEDS SERIOUS ENHANCEMENTS.
- * But it's very tricky to get right even in C.
- */
-__wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
-{
-	memcpy(dst, src, len);
-	return csum_partial(dst, len, sum);
-}
-
-EXPORT_SYMBOL(csum_partial_copy_nocheck);
diff --git a/arch/m68k/include/asm/checksum.h b/arch/m68k/include/asm/checksum.h
index 3f2c15d6f18c..ab16881d84cb 100644
--- a/arch/m68k/include/asm/checksum.h
+++ b/arch/m68k/include/asm/checksum.h
@@ -31,6 +31,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum);
  */
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+#define _HAVE_ARCH_CSUM_AND_COPY
 extern __wsum csum_and_copy_from_user(const void __user *src,
 						void *dst,
 						int len, __wsum sum,
diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h
index 181f7d14efb9..abdf1086873d 100644
--- a/arch/mips/include/asm/checksum.h
+++ b/arch/mips/include/asm/checksum.h
@@ -101,9 +101,9 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
  * the same as csum_partial, but copies from user space (but on MIPS
  * we have just one address space, so this is identical to the above)
  */
+#define _HAVE_ARCH_CSUM_AND_COPY
 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
 				       int len, __wsum sum);
-#define csum_partial_copy_nocheck csum_partial_copy_nocheck
 
 /*
  *	Fold a partial checksum without adding pseudo headers
diff --git a/arch/nios2/include/asm/checksum.h b/arch/nios2/include/asm/checksum.h
index b4316c361729..69004e07a1ba 100644
--- a/arch/nios2/include/asm/checksum.h
+++ b/arch/nios2/include/asm/checksum.h
@@ -12,10 +12,6 @@
 
 /* Take these from lib/checksum.c */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
-__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len,
-				__wsum sum);
-#define csum_partial_copy_nocheck csum_partial_copy_nocheck
-
 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
 extern __sum16 ip_compute_csum(const void *buff, int len);
 
diff --git a/arch/parisc/include/asm/checksum.h b/arch/parisc/include/asm/checksum.h
index fe8c63b2d2c3..522cd574c068 100644
--- a/arch/parisc/include/asm/checksum.h
+++ b/arch/parisc/include/asm/checksum.h
@@ -18,14 +18,6 @@
  */
 extern __wsum csum_partial(const void *, int, __wsum);
 
-/*
- * The same as csum_partial, but copies from src while it checksums.
- *
- * Here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-extern __wsum csum_partial_copy_nocheck(const void *, void *, int, __wsum);
-
 /*
  *	Optimized for IP headers, which always checksum on 4 octet boundaries.
  *
diff --git a/arch/parisc/lib/checksum.c b/arch/parisc/lib/checksum.c
index c6f161583549..4818f3db84a5 100644
--- a/arch/parisc/lib/checksum.c
+++ b/arch/parisc/lib/checksum.c
@@ -106,20 +106,3 @@ __wsum csum_partial(const void *buff, int len, __wsum sum)
 }
 
 EXPORT_SYMBOL(csum_partial);
-
-/*
- * copy while checksumming, otherwise like csum_partial
- */
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-				       int len, __wsum sum)
-{
-	/*
-	 * It's 2:30 am and I don't feel like doing it real ...
-	 * This is lots slower than the real thing (tm)
-	 */
-	sum = csum_partial(src, len, sum);
-	memcpy(dst, src, len);
-
-	return sum;
-}
-EXPORT_SYMBOL(csum_partial_copy_nocheck);
diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index 9cce06194dcc..d75fc5bf8f37 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -29,6 +29,7 @@ extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
 				    int len, __wsum sum, int *err_ptr);
 
+#define _HAVE_ARCH_CSUM_AND_COPY
 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
         csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
 
diff --git a/arch/s390/include/asm/checksum.h b/arch/s390/include/asm/checksum.h
index 6d01c96aeb5c..6813bfa1eeb7 100644
--- a/arch/s390/include/asm/checksum.h
+++ b/arch/s390/include/asm/checksum.h
@@ -39,13 +39,6 @@ csum_partial(const void *buff, int len, __wsum sum)
 	return sum;
 }
 
-static inline __wsum
-csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum)
-{
-        memcpy(dst,src,len);
-	return csum_partial(dst, len, sum);
-}
-
 /*
  *      Fold a partial checksum without adding pseudo headers
  */
diff --git a/arch/sh/include/asm/checksum_32.h b/arch/sh/include/asm/checksum_32.h
index 91571a42e44e..87269642d78d 100644
--- a/arch/sh/include/asm/checksum_32.h
+++ b/arch/sh/include/asm/checksum_32.h
@@ -34,6 +34,7 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
 					    int len, __wsum sum,
 					    int *src_err_ptr, int *dst_err_ptr);
 
+#define _HAVE_ARCH_CSUM_AND_COPY
 /*
  *	Note: when you get a NULL pointer exception here this means someone
  *	passed in an incorrect kernel address to one of these functions.
diff --git a/arch/sparc/include/asm/checksum.h b/arch/sparc/include/asm/checksum.h
index a6256cb6fc5c..deb4fe5aeafd 100644
--- a/arch/sparc/include/asm/checksum.h
+++ b/arch/sparc/include/asm/checksum.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef ___ASM_SPARC_CHECKSUM_H
 #define ___ASM_SPARC_CHECKSUM_H
+#define _HAVE_ARCH_CSUM_AND_COPY
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 #if defined(__sparc__) && defined(__arch64__)
 #include <asm/checksum_64.h>
diff --git a/arch/x86/include/asm/checksum.h b/arch/x86/include/asm/checksum.h
index 0ada98d5d09f..bca625a60186 100644
--- a/arch/x86/include/asm/checksum.h
+++ b/arch/x86/include/asm/checksum.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #define  _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1
 #define HAVE_CSUM_COPY_USER
+#define _HAVE_ARCH_CSUM_AND_COPY
 #ifdef CONFIG_X86_32
 # include <asm/checksum_32.h>
 #else
diff --git a/arch/x86/um/asm/checksum.h b/arch/x86/um/asm/checksum.h
index ff6bba2c8ab6..b07824500363 100644
--- a/arch/x86/um/asm/checksum.h
+++ b/arch/x86/um/asm/checksum.h
@@ -20,22 +20,6 @@
  */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
-/*
- *	Note: when you get a NULL pointer exception here this means someone
- *	passed in an incorrect kernel address to one of these functions.
- *
- *	If you use these functions directly please don't forget the
- *	access_ok().
- */
-
-static __inline__
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-				       int len, __wsum sum)
-{
-	memcpy(dst, src, len);
-	return csum_partial(dst, len, sum);
-}
-
 /**
  * csum_fold - Fold and invert a 32bit checksum.
  * sum: 32bit unfolded sum
diff --git a/arch/xtensa/include/asm/checksum.h b/arch/xtensa/include/asm/checksum.h
index 243a5fe79d3c..0c879099977f 100644
--- a/arch/xtensa/include/asm/checksum.h
+++ b/arch/xtensa/include/asm/checksum.h
@@ -41,6 +41,7 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
 					    int len, __wsum sum,
 					    int *src_err_ptr, int *dst_err_ptr);
 
+#define _HAVE_ARCH_CSUM_AND_COPY
 /*
  *	Note: when you get a NULL pointer exception here this means someone
  *	passed in an incorrect kernel address to one of these functions.
diff --git a/include/asm-generic/checksum.h b/include/asm-generic/checksum.h
index cd8b75aa770d..43e18db89c14 100644
--- a/include/asm-generic/checksum.h
+++ b/include/asm-generic/checksum.h
@@ -16,18 +16,6 @@
  */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
-/*
- * the same as csum_partial, but copies from src while it
- * checksums
- *
- * here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-#ifndef csum_partial_copy_nocheck
-__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len,
-		__wsum sum);
-#endif
-
 #ifndef ip_fast_csum
 /*
  * This is a version of ip_compute_csum() optimized for IP headers,
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 46754ba9d7b7..db9d02b5f88a 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -47,6 +47,15 @@ static __inline__ __wsum csum_and_copy_to_user
 }
 #endif
 
+#ifndef _HAVE_ARCH_CSUM_AND_COPY
+static inline __wsum
+csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
+{
+	memcpy(dst, src, len);
+	return csum_partial(dst, len, sum);
+}
+#endif
+
 #ifndef HAVE_ARCH_CSUM_ADD
 static inline __wsum csum_add(__wsum csum, __wsum addend)
 {
diff --git a/lib/checksum.c b/lib/checksum.c
index c7861e84c526..6860d6b05a17 100644
--- a/lib/checksum.c
+++ b/lib/checksum.c
@@ -145,17 +145,6 @@ __sum16 ip_compute_csum(const void *buff, int len)
 }
 EXPORT_SYMBOL(ip_compute_csum);
 
-/*
- * copy from ds while checksumming, otherwise like csum_partial
- */
-__wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
-{
-	memcpy(dst, src, len);
-	return csum_partial(dst, len, sum);
-}
-EXPORT_SYMBOL(csum_partial_copy_nocheck);
-
 #ifndef csum_tcpudp_nofold
 static inline u32 from64to32(u64 x)
 {

From cc44c17baf7f3f833d36b2f2a1edb1cc0b6f2cc4 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 11 Jul 2020 00:12:07 -0400
Subject: [PATCH 04/19] csum_partial_copy_nocheck(): drop the last argument

It's always 0.  Note that we theoretically could use ~0U as well -
result will be the same modulo 0xffff, _if_ the damn thing did the
right thing for any value of initial sum; later we'll make use of
that when convenient.

However, unlike csum_and_copy_..._user(), there are instances that
did not work for arbitrary initial sums; c6x is one such.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/alpha/include/asm/checksum.h    | 2 +-
 arch/alpha/lib/csum_partial_copy.c   | 4 ++--
 arch/arm/include/asm/checksum.h      | 2 +-
 arch/arm/lib/csumpartialcopy.S       | 5 +++--
 arch/c6x/include/asm/checksum.h      | 2 +-
 arch/c6x/lib/csum_64plus.S           | 4 +---
 arch/m68k/include/asm/checksum.h     | 3 +--
 arch/m68k/lib/checksum.c             | 3 ++-
 arch/mips/include/asm/checksum.h     | 7 +++++--
 arch/mips/lib/csum_partial.S         | 4 ++--
 arch/powerpc/include/asm/checksum.h  | 4 ++--
 arch/sh/include/asm/checksum_32.h    | 5 ++---
 arch/sparc/include/asm/checksum_32.h | 4 ++--
 arch/sparc/include/asm/checksum_64.h | 8 ++++++--
 arch/sparc/lib/csum_copy.S           | 2 +-
 arch/x86/include/asm/checksum_32.h   | 5 ++---
 arch/x86/include/asm/checksum_64.h   | 3 +--
 arch/x86/lib/csum-wrappers_64.c      | 4 ++--
 arch/xtensa/include/asm/checksum.h   | 5 ++---
 drivers/net/ethernet/3com/typhoon.c  | 3 +--
 include/net/checksum.h               | 4 ++--
 lib/iov_iter.c                       | 2 +-
 net/core/skbuff.c                    | 4 ++--
 net/ipv4/icmp.c                      | 2 +-
 net/ipv4/ip_output.c                 | 2 +-
 net/ipv4/raw.c                       | 2 +-
 net/ipv6/raw.c                       | 2 +-
 27 files changed, 49 insertions(+), 48 deletions(-)

diff --git a/arch/alpha/include/asm/checksum.h b/arch/alpha/include/asm/checksum.h
index 7e8e4fa4362d..84f9faea864a 100644
--- a/arch/alpha/include/asm/checksum.h
+++ b/arch/alpha/include/asm/checksum.h
@@ -45,7 +45,7 @@ extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 #define _HAVE_ARCH_CSUM_AND_COPY
 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *errp);
 
-__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);
 
 
 /*
diff --git a/arch/alpha/lib/csum_partial_copy.c b/arch/alpha/lib/csum_partial_copy.c
index af1dad74e933..f363dc89fcbe 100644
--- a/arch/alpha/lib/csum_partial_copy.c
+++ b/arch/alpha/lib/csum_partial_copy.c
@@ -372,13 +372,13 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len,
 EXPORT_SYMBOL(csum_and_copy_from_user);
 
 __wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
+csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
 	__wsum checksum;
 	mm_segment_t oldfs = get_fs();
 	set_fs(KERNEL_DS);
 	checksum = csum_and_copy_from_user((__force const void __user *)src,
-						dst, len, sum, NULL);
+						dst, len, 0, NULL);
 	set_fs(oldfs);
 	return checksum;
 }
diff --git a/arch/arm/include/asm/checksum.h b/arch/arm/include/asm/checksum.h
index 53f769508540..7612b2bd4e9b 100644
--- a/arch/arm/include/asm/checksum.h
+++ b/arch/arm/include/asm/checksum.h
@@ -35,7 +35,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum);
  */
 
 __wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+csum_partial_copy_nocheck(const void *src, void *dst, int len);
 
 __wsum
 csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr);
diff --git a/arch/arm/lib/csumpartialcopy.S b/arch/arm/lib/csumpartialcopy.S
index 184d97254a7a..aab914fbc86b 100644
--- a/arch/arm/lib/csumpartialcopy.S
+++ b/arch/arm/lib/csumpartialcopy.S
@@ -9,13 +9,14 @@
 
 		.text
 
-/* Function: __u32 csum_partial_copy_nocheck(const char *src, char *dst, int len, __u32 sum)
- * Params  : r0 = src, r1 = dst, r2 = len, r3 = checksum
+/* Function: __u32 csum_partial_copy_nocheck(const char *src, char *dst, int len)
+ * Params  : r0 = src, r1 = dst, r2 = len
  * Returns : r0 = new checksum
  */
 
 		.macro	save_regs
 		stmfd	sp!, {r1, r4 - r8, lr}
+		mov	r3, #0
 		.endm
 
 		.macro	load_regs
diff --git a/arch/c6x/include/asm/checksum.h b/arch/c6x/include/asm/checksum.h
index fa31bdc186b2..934918def632 100644
--- a/arch/c6x/include/asm/checksum.h
+++ b/arch/c6x/include/asm/checksum.h
@@ -27,7 +27,7 @@ csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
 #define csum_tcpudp_nofold csum_tcpudp_nofold
 
 #define _HAVE_ARCH_CSUM_AND_COPY
-extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);
 
 #include <asm-generic/checksum.h>
 
diff --git a/arch/c6x/lib/csum_64plus.S b/arch/c6x/lib/csum_64plus.S
index 9c07127485d1..57148866d8d3 100644
--- a/arch/c6x/lib/csum_64plus.S
+++ b/arch/c6x/lib/csum_64plus.S
@@ -24,7 +24,6 @@
 ENTRY(csum_partial_copy_nocheck)
 	MVC	.S2	ILC,B30
 
-	MV	.D1X	B6,A31		; given csum
 	ZERO	.D1	A9		; csum (a side)
 ||	ZERO	.D2	B9		; csum (b side)
 ||	SHRU	.S2X	A6,2,B5		; len / 4
@@ -144,8 +143,7 @@ L91:	SHRU	.S2X	A9,16,B4
 	SHRU	.S1	A9,16,A0
    [A0]	BNOP	.S1	L91,5
 
-L10:	ADD	.D1	A31,A9,A9
-	MV	.D1	A9,A4
+L10:	MV	.D1	A9,A4
 
 	BNOP	.S2	B3,4
 	MVC	.S2	B30,ILC
diff --git a/arch/m68k/include/asm/checksum.h b/arch/m68k/include/asm/checksum.h
index ab16881d84cb..d5e74c64b6cd 100644
--- a/arch/m68k/include/asm/checksum.h
+++ b/arch/m68k/include/asm/checksum.h
@@ -38,8 +38,7 @@ extern __wsum csum_and_copy_from_user(const void __user *src,
 						int *csum_err);
 
 extern __wsum csum_partial_copy_nocheck(const void *src,
-					      void *dst, int len,
-					      __wsum sum);
+					      void *dst, int len);
 
 /*
  *	This is a version of ip_fast_csum() optimized for IP headers,
diff --git a/arch/m68k/lib/checksum.c b/arch/m68k/lib/checksum.c
index 31797be9a3dc..86ddd2ee187d 100644
--- a/arch/m68k/lib/checksum.c
+++ b/arch/m68k/lib/checksum.c
@@ -324,9 +324,10 @@ EXPORT_SYMBOL(csum_and_copy_from_user);
  */
 
 __wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
+csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
 	unsigned long tmp1, tmp2;
+	__wsum sum = 0;
 	__asm__("movel %2,%4\n\t"
 		"btst #1,%4\n\t"	/* Check alignment */
 		"jeq 2f\n\t"
diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h
index abdf1086873d..ec3159dbc1b3 100644
--- a/arch/mips/include/asm/checksum.h
+++ b/arch/mips/include/asm/checksum.h
@@ -102,8 +102,11 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
  * we have just one address space, so this is identical to the above)
  */
 #define _HAVE_ARCH_CSUM_AND_COPY
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-				       int len, __wsum sum);
+__wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
+{
+	return __csum_partial_copy_nocheck(src, dst, len, 0);
+}
 
 /*
  *	Fold a partial checksum without adding pseudo headers
diff --git a/arch/mips/lib/csum_partial.S b/arch/mips/lib/csum_partial.S
index 87fda0713b84..8d70855b0914 100644
--- a/arch/mips/lib/csum_partial.S
+++ b/arch/mips/lib/csum_partial.S
@@ -462,8 +462,8 @@ EXPORT_SYMBOL(csum_partial)
 	lw	errptr, 16(sp)
 #endif
 	.if \__nocheck == 1
-	FEXPORT(csum_partial_copy_nocheck)
-	EXPORT_SYMBOL(csum_partial_copy_nocheck)
+	FEXPORT(__csum_partial_copy_nocheck)
+	EXPORT_SYMBOL(__csum_partial_copy_nocheck)
 	.endif
 	move	sum, zero
 	move	odd, zero
diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index d75fc5bf8f37..64299785f639 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -30,8 +30,8 @@ extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
 				    int len, __wsum sum, int *err_ptr);
 
 #define _HAVE_ARCH_CSUM_AND_COPY
-#define csum_partial_copy_nocheck(src, dst, len, sum)   \
-        csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
+#define csum_partial_copy_nocheck(src, dst, len)   \
+        csum_partial_copy_generic((src), (dst), (len), 0, NULL, NULL)
 
 
 /*
diff --git a/arch/sh/include/asm/checksum_32.h b/arch/sh/include/asm/checksum_32.h
index 87269642d78d..e8bf84d3b843 100644
--- a/arch/sh/include/asm/checksum_32.h
+++ b/arch/sh/include/asm/checksum_32.h
@@ -43,10 +43,9 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
  *	access_ok().
  */
 static inline
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-				 int len, __wsum sum)
+__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
+	return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
 }
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
diff --git a/arch/sparc/include/asm/checksum_32.h b/arch/sparc/include/asm/checksum_32.h
index 479a0b812af5..d21d114436ba 100644
--- a/arch/sparc/include/asm/checksum_32.h
+++ b/arch/sparc/include/asm/checksum_32.h
@@ -42,7 +42,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum);
 unsigned int __csum_partial_copy_sparc_generic (const unsigned char *, unsigned char *);
 
 static inline __wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
+csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
 	register unsigned int ret asm("o0") = (unsigned int)src;
 	register char *d asm("o1") = dst;
@@ -52,7 +52,7 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
 		"call __csum_partial_copy_sparc_generic\n\t"
 		" mov %6, %%g7\n"
 	: "=&r" (ret), "=&r" (d), "=&r" (l)
-	: "0" (ret), "1" (d), "2" (l), "r" (sum)
+	: "0" (ret), "1" (d), "2" (l), "r" (0)
 	: "o2", "o3", "o4", "o5", "o7",
 	  "g2", "g3", "g4", "g5", "g7",
 	  "memory", "cc");
diff --git a/arch/sparc/include/asm/checksum_64.h b/arch/sparc/include/asm/checksum_64.h
index 0fa4433f5662..7aebdbe3ac96 100644
--- a/arch/sparc/include/asm/checksum_64.h
+++ b/arch/sparc/include/asm/checksum_64.h
@@ -38,8 +38,12 @@ __wsum csum_partial(const void * buff, int len, __wsum sum);
  * here even more important to align src and dst on a 32-bit (or even
  * better 64-bit) boundary
  */
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-				 int len, __wsum sum);
+__wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+
+static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
+{
+	return __csum_partial_copy_nocheck(src, dst, len, 0);
+}
 
 long __csum_partial_copy_from_user(const void __user *src,
 				   void *dst, int len,
diff --git a/arch/sparc/lib/csum_copy.S b/arch/sparc/lib/csum_copy.S
index 26c644ba3ecb..72c900d21b12 100644
--- a/arch/sparc/lib/csum_copy.S
+++ b/arch/sparc/lib/csum_copy.S
@@ -33,7 +33,7 @@
 #endif
 
 #ifndef FUNC_NAME
-#define FUNC_NAME	csum_partial_copy_nocheck
+#define FUNC_NAME	__csum_partial_copy_nocheck
 #endif
 
 	.register	%g2, #scratch
diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h
index 11624c8a9d8d..137a3033edcc 100644
--- a/arch/x86/include/asm/checksum_32.h
+++ b/arch/x86/include/asm/checksum_32.h
@@ -38,10 +38,9 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
  *	If you use these functions directly please don't forget the
  *	access_ok().
  */
-static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst,
-					       int len, __wsum sum)
+static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
+	return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
 }
 
 static inline __wsum csum_and_copy_from_user(const void __user *src,
diff --git a/arch/x86/include/asm/checksum_64.h b/arch/x86/include/asm/checksum_64.h
index 0a289b87e872..5339f5dfc776 100644
--- a/arch/x86/include/asm/checksum_64.h
+++ b/arch/x86/include/asm/checksum_64.h
@@ -139,8 +139,7 @@ extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
 					  int len, __wsum isum, int *errp);
 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
 					int len, __wsum isum, int *errp);
-extern __wsum csum_partial_copy_nocheck(const void *src, void *dst,
-					int len, __wsum sum);
+extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);
 
 /**
  * ip_compute_csum - Compute an 16bit IP checksum.
diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c
index ee63d7576fd2..245f929a1c2c 100644
--- a/arch/x86/lib/csum-wrappers_64.c
+++ b/arch/x86/lib/csum-wrappers_64.c
@@ -129,9 +129,9 @@ EXPORT_SYMBOL(csum_and_copy_to_user);
  * Returns an 32bit unfolded checksum of the buffer.
  */
 __wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
+csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
+	return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
 }
 EXPORT_SYMBOL(csum_partial_copy_nocheck);
 
diff --git a/arch/xtensa/include/asm/checksum.h b/arch/xtensa/include/asm/checksum.h
index 0c879099977f..dc09448935bf 100644
--- a/arch/xtensa/include/asm/checksum.h
+++ b/arch/xtensa/include/asm/checksum.h
@@ -47,10 +47,9 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
  *	passed in an incorrect kernel address to one of these functions.
  */
 static inline
-__wsum csum_partial_copy_nocheck(const void *src, void *dst,
-					int len, __wsum sum)
+__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
+	return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
 }
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
diff --git a/drivers/net/ethernet/3com/typhoon.c b/drivers/net/ethernet/3com/typhoon.c
index d3b30bacc94e..049cc0158a64 100644
--- a/drivers/net/ethernet/3com/typhoon.c
+++ b/drivers/net/ethernet/3com/typhoon.c
@@ -1419,8 +1419,7 @@ typhoon_download_firmware(struct typhoon *tp)
 			 * the checksum, we can do this once, at the end.
 			 */
 			csum = csum_fold(csum_partial_copy_nocheck(image_data,
-								   dpage, len,
-								   0));
+								   dpage, len));
 
 			iowrite32(len, ioaddr + TYPHOON_REG_BOOT_LENGTH);
 			iowrite32(le16_to_cpu((__force __le16)csum),
diff --git a/include/net/checksum.h b/include/net/checksum.h
index db9d02b5f88a..1029191986e3 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -49,10 +49,10 @@ static __inline__ __wsum csum_and_copy_to_user
 
 #ifndef _HAVE_ARCH_CSUM_AND_COPY
 static inline __wsum
-csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
+csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
 	memcpy(dst, src, len);
-	return csum_partial(dst, len, sum);
+	return csum_partial(dst, len, 0);
 }
 #endif
 
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 5e40786c8f12..84f3a9156684 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -581,7 +581,7 @@ static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
 static __wsum csum_and_memcpy(void *to, const void *from, size_t len,
 			      __wsum sum, size_t off)
 {
-	__wsum next = csum_partial_copy_nocheck(from, to, len, 0);
+	__wsum next = csum_partial_copy_nocheck(from, to, len);
 	return csum_block_add(sum, next, off);
 }
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 6e806da2913e..48dd4757b898 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2736,7 +2736,7 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
 		if (copy > len)
 			copy = len;
 		csum = csum_partial_copy_nocheck(skb->data + offset, to,
-						 copy, 0);
+						 copy);
 		if ((len -= copy) == 0)
 			return csum;
 		offset += copy;
@@ -2766,7 +2766,7 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
 				vaddr = kmap_atomic(p);
 				csum2 = csum_partial_copy_nocheck(vaddr + p_off,
 								  to + copied,
-								  p_len, 0);
+								  p_len);
 				kunmap_atomic(vaddr);
 				csum = csum_block_add(csum, csum2, pos);
 				pos += p_len;
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index e23dd5fc2e73..bdaaee52c41b 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -381,7 +381,7 @@ static void icmp_push_reply(struct icmp_bxm *icmp_param,
 
 		csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
 						 (char *)icmph,
-						 icmp_param->head_len, 0);
+						 icmp_param->head_len);
 		skb_queue_walk(&sk->sk_write_queue, skb1) {
 			csum = csum_add(csum, skb1->csum);
 		}
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 5bd059853376..bd79ea3e8c44 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1648,7 +1648,7 @@ static int ip_reply_glue_bits(void *dptr, char *to, int offset,
 {
 	__wsum csum;
 
-	csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0);
+	csum = csum_partial_copy_nocheck(dptr+offset, to, len);
 	skb->csum = csum_block_add(skb->csum, csum, odd);
 	return 0;
 }
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 6fd4330287c2..79392154c30a 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -478,7 +478,7 @@ static int raw_getfrag(void *from, char *to, int offset, int len, int odd,
 			skb->csum = csum_block_add(
 				skb->csum,
 				csum_partial_copy_nocheck(rfv->hdr.c + offset,
-							  to, copy, 0),
+							  to, copy),
 				odd);
 
 		odd = 0;
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 874f01cd7aec..6e4ab80a3b94 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -746,7 +746,7 @@ static int raw6_getfrag(void *from, char *to, int offset, int len, int odd,
 			skb->csum = csum_block_add(
 				skb->csum,
 				csum_partial_copy_nocheck(rfv->c + offset,
-							  to, copy, 0),
+							  to, copy),
 				odd);
 
 		odd = 0;

From 99a2c96d52d312b11a943372964226fa134de3b1 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 11 Jul 2020 23:51:04 -0400
Subject: [PATCH 05/19] csum_and_copy_..._user(): pass 0xffffffff instead of 0
 as initial sum

Preparation for the change of calling conventions; right now all
callers pass 0 as initial sum.  Passing 0xffffffff instead yields
the values comparable mod 0xffff and guarantees that 0 will not
be returned on success.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 lib/iov_iter.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 84f3a9156684..437fbc14c972 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1452,7 +1452,7 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
 		int err = 0;
 		next = csum_and_copy_from_user(v.iov_base,
 					       (to += v.iov_len) - v.iov_len,
-					       v.iov_len, 0, &err);
+					       v.iov_len, ~0U, &err);
 		if (!err) {
 			sum = csum_block_add(sum, next, off);
 			off += v.iov_len;
@@ -1494,7 +1494,7 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
 		int err = 0;
 		next = csum_and_copy_from_user(v.iov_base,
 					       (to += v.iov_len) - v.iov_len,
-					       v.iov_len, 0, &err);
+					       v.iov_len, ~0U, &err);
 		if (err)
 			return false;
 		sum = csum_block_add(sum, next, off);
@@ -1540,7 +1540,7 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump,
 		int err = 0;
 		next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
 					     v.iov_base,
-					     v.iov_len, 0, &err);
+					     v.iov_len, ~0U, &err);
 		if (!err) {
 			sum = csum_block_add(sum, next, off);
 			off += v.iov_len;

From c693cc4676a055c4126e487b30b0a96ea7ec9936 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 11 Jul 2020 00:27:49 -0400
Subject: [PATCH 06/19] saner calling conventions for csum_and_copy_..._user()

All callers of these primitives will
	* discard anything we might've copied in case of error
	* ignore the csum value in case of error
	* always pass 0xffffffff as the initial sum, so the
resulting csum value (in case of success, that is) will never be 0.

That suggest the following calling conventions:
	* don't pass err_ptr - just return 0 on error.
	* don't bother with zeroing destination, etc. in case of error
	* don't pass the initial sum - just use 0xffffffff.

This commit does the minimal conversion in the instances of csum_and_copy_...();
the changes of actual asm code behind them are done later in the series.
Note that this asm code is often shared with csum_partial_copy_nocheck();
the difference is that csum_partial_copy_nocheck() passes 0 for initial
sum while csum_and_copy_..._user() pass 0xffffffff.  Fortunately, we are
free to pass 0xffffffff in all cases and subsequent patches will use that
freedom without any special comments.

A part that could be split off: parisc and uml/i386 claimed to have
csum_and_copy_to_user() instances of their own, but those were identical
to the generic one, so we simply drop them.  Not sure if it's worth
a separate commit...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/alpha/include/asm/checksum.h    |  2 +-
 arch/alpha/lib/csum_partial_copy.c   | 25 +++++-----
 arch/arm/include/asm/checksum.h      | 13 +++---
 arch/m68k/include/asm/checksum.h     |  3 +-
 arch/m68k/lib/checksum.c             |  8 ++--
 arch/mips/include/asm/checksum.h     | 46 +++++++++---------
 arch/parisc/include/asm/checksum.h   | 20 --------
 arch/powerpc/include/asm/checksum.h  |  4 +-
 arch/powerpc/lib/checksum_wrappers.c | 70 +++++++++-------------------
 arch/sh/include/asm/checksum_32.h    | 34 +++++++-------
 arch/sparc/include/asm/checksum_32.h | 65 ++++++++++++--------------
 arch/sparc/include/asm/checksum_64.h | 14 +++---
 arch/x86/include/asm/checksum_32.h   | 35 ++++++--------
 arch/x86/include/asm/checksum_64.h   |  6 +--
 arch/x86/lib/csum-wrappers_64.c      | 38 +++++++--------
 arch/x86/um/asm/checksum_32.h        | 23 ---------
 arch/xtensa/include/asm/checksum.h   | 30 ++++++------
 include/net/checksum.h               | 15 +++---
 lib/iov_iter.c                       | 19 ++++----
 19 files changed, 183 insertions(+), 287 deletions(-)

diff --git a/arch/alpha/include/asm/checksum.h b/arch/alpha/include/asm/checksum.h
index 84f9faea864a..99d631e146b2 100644
--- a/arch/alpha/include/asm/checksum.h
+++ b/arch/alpha/include/asm/checksum.h
@@ -43,7 +43,7 @@ extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  */
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 #define _HAVE_ARCH_CSUM_AND_COPY
-__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *errp);
+__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len);
 
 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);
 
diff --git a/arch/alpha/lib/csum_partial_copy.c b/arch/alpha/lib/csum_partial_copy.c
index f363dc89fcbe..3c0e89c39ddb 100644
--- a/arch/alpha/lib/csum_partial_copy.c
+++ b/arch/alpha/lib/csum_partial_copy.c
@@ -325,30 +325,27 @@ csum_partial_cfu_unaligned(const unsigned long __user * src,
 }
 
 __wsum
-csum_and_copy_from_user(const void __user *src, void *dst, int len,
-			       __wsum sum, int *errp)
+csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	unsigned long checksum = (__force u32) sum;
+	unsigned long checksum = ~0U;
 	unsigned long soff = 7 & (unsigned long) src;
 	unsigned long doff = 7 & (unsigned long) dst;
+	int err = 0;
 
 	if (len) {
-		if (!access_ok(src, len)) {
-			if (errp) *errp = -EFAULT;
-			memset(dst, 0, len);
-			return sum;
-		}
+		if (!access_ok(src, len))
+			return 0;
 		if (!doff) {
 			if (!soff)
 				checksum = csum_partial_cfu_aligned(
 					(const unsigned long __user *) src,
 					(unsigned long *) dst,
-					len-8, checksum, errp);
+					len-8, checksum, &err);
 			else
 				checksum = csum_partial_cfu_dest_aligned(
 					(const unsigned long __user *) src,
 					(unsigned long *) dst,
-					soff, len-8, checksum, errp);
+					soff, len-8, checksum, &err);
 		} else {
 			unsigned long partial_dest;
 			ldq_u(partial_dest, dst);
@@ -357,15 +354,15 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len,
 					(const unsigned long __user *) src,
 					(unsigned long *) dst,
 					doff, len-8, checksum,
-					partial_dest, errp);
+					partial_dest, &err);
 			else
 				checksum = csum_partial_cfu_unaligned(
 					(const unsigned long __user *) src,
 					(unsigned long *) dst,
 					soff, doff, len-8, checksum,
-					partial_dest, errp);
+					partial_dest, &err);
 		}
-		checksum = from64to16 (checksum);
+		checksum = err ? 0 : from64to16 (checksum);
 	}
 	return (__force __wsum)checksum;
 }
@@ -378,7 +375,7 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len)
 	mm_segment_t oldfs = get_fs();
 	set_fs(KERNEL_DS);
 	checksum = csum_and_copy_from_user((__force const void __user *)src,
-						dst, len, 0, NULL);
+						dst, len);
 	set_fs(oldfs);
 	return checksum;
 }
diff --git a/arch/arm/include/asm/checksum.h b/arch/arm/include/asm/checksum.h
index 7612b2bd4e9b..1601c132b064 100644
--- a/arch/arm/include/asm/checksum.h
+++ b/arch/arm/include/asm/checksum.h
@@ -43,16 +43,15 @@ csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum s
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 #define _HAVE_ARCH_CSUM_AND_COPY
 static inline
-__wsum csum_and_copy_from_user (const void __user *src, void *dst,
-				      int len, __wsum sum, int *err_ptr)
+__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	if (access_ok(src, len))
-		return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
+	int err = 0;
 
-	if (len)
-		*err_ptr = -EFAULT;
+	if (!access_ok(src, len))
+		return 0;
 
-	return sum;
+	sum = csum_partial_copy_from_user(src, dst, len, ~0U, &err);
+	return err ? 0 : sum;
 }
 
 /*
diff --git a/arch/m68k/include/asm/checksum.h b/arch/m68k/include/asm/checksum.h
index d5e74c64b6cd..692e7b6cc042 100644
--- a/arch/m68k/include/asm/checksum.h
+++ b/arch/m68k/include/asm/checksum.h
@@ -34,8 +34,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum);
 #define _HAVE_ARCH_CSUM_AND_COPY
 extern __wsum csum_and_copy_from_user(const void __user *src,
 						void *dst,
-						int len, __wsum sum,
-						int *csum_err);
+						int len);
 
 extern __wsum csum_partial_copy_nocheck(const void *src,
 					      void *dst, int len);
diff --git a/arch/m68k/lib/checksum.c b/arch/m68k/lib/checksum.c
index 86ddd2ee187d..3aeca261f622 100644
--- a/arch/m68k/lib/checksum.c
+++ b/arch/m68k/lib/checksum.c
@@ -129,8 +129,7 @@ EXPORT_SYMBOL(csum_partial);
  */
 
 __wsum
-csum_and_copy_from_user(const void __user *src, void *dst,
-			    int len, __wsum sum, int *csum_err)
+csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
 	/*
 	 * GCC doesn't like more than 10 operands for the asm
@@ -138,6 +137,7 @@ csum_and_copy_from_user(const void __user *src, void *dst,
 	 * code.
 	 */
 	unsigned long tmp1, tmp2;
+	__wsum sum = ~0U;
 
 	__asm__("movel %2,%4\n\t"
 		"btst #1,%4\n\t"	/* Check alignment */
@@ -311,9 +311,7 @@ csum_and_copy_from_user(const void __user *src, void *dst,
 		: "0" (sum), "1" (len), "2" (src), "3" (dst)
 	    );
 
-	*csum_err = tmp2;
-
-	return(sum);
+	return tmp2 ? 0 : sum;
 }
 
 EXPORT_SYMBOL(csum_and_copy_from_user);
diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h
index ec3159dbc1b3..9dfce3522760 100644
--- a/arch/mips/include/asm/checksum.h
+++ b/arch/mips/include/asm/checksum.h
@@ -60,16 +60,15 @@ __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
-__wsum csum_and_copy_from_user(const void __user *src, void *dst,
-			       int len, __wsum sum, int *err_ptr)
+__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	if (access_ok(src, len))
-		return csum_partial_copy_from_user(src, dst, len, sum,
-						   err_ptr);
-	if (len)
-		*err_ptr = -EFAULT;
+	__wsum sum = ~0U;
+	int err = 0;
 
-	return sum;
+	if (!access_ok(src, len))
+		return 0;
+	sum = csum_partial_copy_from_user(src, dst, len, sum, &err);
+	return err ? 0 : sum;
 }
 
 /*
@@ -77,24 +76,23 @@ __wsum csum_and_copy_from_user(const void __user *src, void *dst,
  */
 #define HAVE_CSUM_COPY_USER
 static inline
-__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
-			     __wsum sum, int *err_ptr)
+__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
 {
-	might_fault();
-	if (access_ok(dst, len)) {
-		if (uaccess_kernel())
-			return __csum_partial_copy_kernel(src,
-							  (__force void *)dst,
-							  len, sum, err_ptr);
-		else
-			return __csum_partial_copy_to_user(src,
-							   (__force void *)dst,
-							   len, sum, err_ptr);
-	}
-	if (len)
-		*err_ptr = -EFAULT;
+	int err = 0;
+	__wsum sum = ~0U;
 
-	return (__force __wsum)-1; /* invalid checksum */
+	might_fault();
+	if (!access_ok(dst, len))
+		return 0;
+	if (uaccess_kernel())
+		sum = __csum_partial_copy_kernel(src,
+						  (__force void *)dst,
+						  len, sum, &err);
+	else
+		sum = __csum_partial_copy_to_user(src,
+						   (__force void *)dst,
+						   len, sum, &err);
+	return err ? 0 : sum;
 }
 
 /*
diff --git a/arch/parisc/include/asm/checksum.h b/arch/parisc/include/asm/checksum.h
index 522cd574c068..3c43baca7b39 100644
--- a/arch/parisc/include/asm/checksum.h
+++ b/arch/parisc/include/asm/checksum.h
@@ -173,25 +173,5 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 	return csum_fold(sum);
 }
 
-/* 
- *	Copy and checksum to user
- */
-#define HAVE_CSUM_COPY_USER
-static __inline__ __wsum csum_and_copy_to_user(const void *src,
-						      void __user *dst,
-						      int len, __wsum sum,
-						      int *err_ptr)
-{
-	/* code stolen from include/asm-mips64 */
-	sum = csum_partial(src, len, sum);
-	 
-	if (copy_to_user(dst, src, len)) {
-		*err_ptr = -EFAULT;
-		return (__force __wsum)-1;
-	}
-
-	return sum;
-}
-
 #endif
 
diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index 64299785f639..dba685d984c0 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -24,10 +24,10 @@ extern __wsum csum_partial_copy_generic(const void *src, void *dst,
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
-				      int len, __wsum sum, int *err_ptr);
+				      int len);
 #define HAVE_CSUM_COPY_USER
 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
-				    int len, __wsum sum, int *err_ptr);
+				    int len);
 
 #define _HAVE_ARCH_CSUM_AND_COPY
 #define csum_partial_copy_nocheck(src, dst, len)   \
diff --git a/arch/powerpc/lib/checksum_wrappers.c b/arch/powerpc/lib/checksum_wrappers.c
index fabe4db28726..b1faa82dd8af 100644
--- a/arch/powerpc/lib/checksum_wrappers.c
+++ b/arch/powerpc/lib/checksum_wrappers.c
@@ -12,82 +12,56 @@
 #include <linux/uaccess.h>
 
 __wsum csum_and_copy_from_user(const void __user *src, void *dst,
-			       int len, __wsum sum, int *err_ptr)
+			       int len)
 {
 	unsigned int csum;
+	int err = 0;
 
 	might_sleep();
+
+	if (unlikely(!access_ok(src, len)))
+		return 0;
+
 	allow_read_from_user(src, len);
 
-	*err_ptr = 0;
-
-	if (!len) {
-		csum = 0;
-		goto out;
-	}
-
-	if (unlikely((len < 0) || !access_ok(src, len))) {
-		*err_ptr = -EFAULT;
-		csum = (__force unsigned int)sum;
-		goto out;
-	}
-
 	csum = csum_partial_copy_generic((void __force *)src, dst,
-					 len, sum, err_ptr, NULL);
+					 len, ~0U, &err, NULL);
 
-	if (unlikely(*err_ptr)) {
+	if (unlikely(err)) {
 		int missing = __copy_from_user(dst, src, len);
 
-		if (missing) {
-			memset(dst + len - missing, 0, missing);
-			*err_ptr = -EFAULT;
-		} else {
-			*err_ptr = 0;
-		}
-
-		csum = csum_partial(dst, len, sum);
+		if (missing)
+			csum = 0;
+		else
+			csum = csum_partial(dst, len, ~0U);
 	}
 
-out:
 	prevent_read_from_user(src, len);
 	return (__force __wsum)csum;
 }
 EXPORT_SYMBOL(csum_and_copy_from_user);
 
-__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
-			     __wsum sum, int *err_ptr)
+__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
 {
 	unsigned int csum;
+	int err = 0;
 
 	might_sleep();
+	if (unlikely(!access_ok(dst, len)))
+		return 0;
+
 	allow_write_to_user(dst, len);
 
-	*err_ptr = 0;
-
-	if (!len) {
-		csum = 0;
-		goto out;
-	}
-
-	if (unlikely((len < 0) || !access_ok(dst, len))) {
-		*err_ptr = -EFAULT;
-		csum = -1; /* invalid checksum */
-		goto out;
-	}
-
 	csum = csum_partial_copy_generic(src, (void __force *)dst,
-					 len, sum, NULL, err_ptr);
+					 len, ~0U, NULL, &err);
 
-	if (unlikely(*err_ptr)) {
-		csum = csum_partial(src, len, sum);
+	if (unlikely(err)) {
+		csum = csum_partial(src, len, ~0U);
 
-		if (copy_to_user(dst, src, len)) {
-			*err_ptr = -EFAULT;
-			csum = -1; /* invalid checksum */
-		}
+		if (copy_to_user(dst, src, len))
+			csum = 0;
 	}
 
-out:
 	prevent_write_to_user(dst, len);
 	return (__force __wsum)csum;
 }
diff --git a/arch/sh/include/asm/checksum_32.h b/arch/sh/include/asm/checksum_32.h
index e8bf84d3b843..a08e8eb924ed 100644
--- a/arch/sh/include/asm/checksum_32.h
+++ b/arch/sh/include/asm/checksum_32.h
@@ -50,15 +50,16 @@ __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
-__wsum csum_and_copy_from_user(const void __user *src, void *dst,
-				   int len, __wsum sum, int *err_ptr)
+__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	if (access_ok(src, len))
-		return csum_partial_copy_generic((__force const void *)src, dst,
-					len, sum, err_ptr, NULL);
-	if (len)
-		*err_ptr = -EFAULT;
-	return sum;
+	int err = 0;
+	__wsum sum = ~0U;
+
+	if (!access_ok(src, len))
+		return 0;
+	sum = csum_partial_copy_generic((__force const void *)src, dst,
+					len, sum, &err, NULL);
+	return err ? 0 : sum;
 }
 
 /*
@@ -199,16 +200,15 @@ static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 #define HAVE_CSUM_COPY_USER
 static inline __wsum csum_and_copy_to_user(const void *src,
 					   void __user *dst,
-					   int len, __wsum sum,
-					   int *err_ptr)
+					   int len)
 {
-	if (access_ok(dst, len))
-		return csum_partial_copy_generic((__force const void *)src,
-						dst, len, sum, NULL, err_ptr);
+	int err = 0;
+	__wsum sum = ~0U;
 
-	if (len)
-		*err_ptr = -EFAULT;
-
-	return (__force __wsum)-1; /* invalid checksum */
+	if (!access_ok(dst, len))
+		return 0;
+	sum = csum_partial_copy_generic((__force const void *)src,
+						dst, len, sum, NULL, &err);
+	return err ? 0 : sum;
 }
 #endif /* __ASM_SH_CHECKSUM_H */
diff --git a/arch/sparc/include/asm/checksum_32.h b/arch/sparc/include/asm/checksum_32.h
index d21d114436ba..b5873b7b7bf0 100644
--- a/arch/sparc/include/asm/checksum_32.h
+++ b/arch/sparc/include/asm/checksum_32.h
@@ -60,19 +60,16 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len)
 }
 
 static inline __wsum
-csum_and_copy_from_user(const void __user *src, void *dst, int len,
-			    __wsum sum, int *err)
+csum_and_copy_from_user(const void __user *src, void *dst, int len)
   {
 	register unsigned long ret asm("o0") = (unsigned long)src;
 	register char *d asm("o1") = dst;
 	register int l asm("g1") = len;
-	register __wsum s asm("g7") = sum;
+	register __wsum s asm("g7") = ~0U;
+	int err = 0;
 
-	if (unlikely(!access_ok(src, len))) {
-		if (len)
-			*err = -EFAULT;
-		return sum;
-	}
+	if (unlikely(!access_ok(src, len)))
+		return 0;
 
 	__asm__ __volatile__ (
 	".section __ex_table,#alloc\n\t"
@@ -83,42 +80,40 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len,
 	"call __csum_partial_copy_sparc_generic\n\t"
 	" st %8, [%%sp + 64]\n"
 	: "=&r" (ret), "=&r" (d), "=&r" (l), "=&r" (s)
-	: "0" (ret), "1" (d), "2" (l), "3" (s), "r" (err)
+	: "0" (ret), "1" (d), "2" (l), "3" (s), "r" (&err)
 	: "o2", "o3", "o4", "o5", "o7", "g2", "g3", "g4", "g5",
 	  "cc", "memory");
-	return (__force __wsum)ret;
+	return err ? 0 : (__force __wsum)ret;
 }
 
 #define HAVE_CSUM_COPY_USER
 
 static inline __wsum
-csum_and_copy_to_user(const void *src, void __user *dst, int len,
-			  __wsum sum, int *err)
+csum_and_copy_to_user(const void *src, void __user *dst, int len)
 {
-	if (!access_ok(dst, len)) {
-		*err = -EFAULT;
-		return sum;
-	} else {
-		register unsigned long ret asm("o0") = (unsigned long)src;
-		register char __user *d asm("o1") = dst;
-		register int l asm("g1") = len;
-		register __wsum s asm("g7") = sum;
+	register unsigned long ret asm("o0") = (unsigned long)src;
+	register char __user *d asm("o1") = dst;
+	register int l asm("g1") = len;
+	register __wsum s asm("g7") = ~0U;
+	int err = 0;
 
-		__asm__ __volatile__ (
-		".section __ex_table,#alloc\n\t"
-		".align 4\n\t"
-		".word 1f,1\n\t"
-		".previous\n"
-		"1:\n\t"
-		"call __csum_partial_copy_sparc_generic\n\t"
-		" st %8, [%%sp + 64]\n"
-		: "=&r" (ret), "=&r" (d), "=&r" (l), "=&r" (s)
-		: "0" (ret), "1" (d), "2" (l), "3" (s), "r" (err)
-		: "o2", "o3", "o4", "o5", "o7",
-		  "g2", "g3", "g4", "g5",
-		  "cc", "memory");
-		return (__force __wsum)ret;
-	}
+	if (!access_ok(dst, len))
+		return 0;
+
+	__asm__ __volatile__ (
+	".section __ex_table,#alloc\n\t"
+	".align 4\n\t"
+	".word 1f,1\n\t"
+	".previous\n"
+	"1:\n\t"
+	"call __csum_partial_copy_sparc_generic\n\t"
+	" st %8, [%%sp + 64]\n"
+	: "=&r" (ret), "=&r" (d), "=&r" (l), "=&r" (s)
+	: "0" (ret), "1" (d), "2" (l), "3" (s), "r" (&err)
+	: "o2", "o3", "o4", "o5", "o7",
+	  "g2", "g3", "g4", "g5",
+	  "cc", "memory");
+	return err ? 0 : (__force __wsum)ret;
 }
 
 /* ihl is always 5 or greater, almost always is 5, and iph is word aligned
diff --git a/arch/sparc/include/asm/checksum_64.h b/arch/sparc/include/asm/checksum_64.h
index 7aebdbe3ac96..4d0bbff43e62 100644
--- a/arch/sparc/include/asm/checksum_64.h
+++ b/arch/sparc/include/asm/checksum_64.h
@@ -51,12 +51,11 @@ long __csum_partial_copy_from_user(const void __user *src,
 
 static inline __wsum
 csum_and_copy_from_user(const void __user *src,
-			    void *dst, int len,
-			    __wsum sum, int *err)
+			    void *dst, int len)
 {
-	long ret = __csum_partial_copy_from_user(src, dst, len, sum);
+	long ret = __csum_partial_copy_from_user(src, dst, len, ~0U);
 	if (ret < 0)
-		*err = -EFAULT;
+		return 0;
 	return (__force __wsum) ret;
 }
 
@@ -70,12 +69,11 @@ long __csum_partial_copy_to_user(const void *src,
 
 static inline __wsum
 csum_and_copy_to_user(const void *src,
-		      void __user *dst, int len,
-		      __wsum sum, int *err)
+		      void __user *dst, int len)
 {
-	long ret = __csum_partial_copy_to_user(src, dst, len, sum);
+	long ret = __csum_partial_copy_to_user(src, dst, len, ~0U);
 	if (ret < 0)
-		*err = -EFAULT;
+		return 0;
 	return (__force __wsum) ret;
 }
 
diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h
index 137a3033edcc..5948cde9e4ad 100644
--- a/arch/x86/include/asm/checksum_32.h
+++ b/arch/x86/include/asm/checksum_32.h
@@ -44,22 +44,19 @@ static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int l
 }
 
 static inline __wsum csum_and_copy_from_user(const void __user *src,
-					     void *dst, int len,
-					     __wsum sum, int *err_ptr)
+					     void *dst, int len)
 {
 	__wsum ret;
+	int err = 0;
 
 	might_sleep();
-	if (!user_access_begin(src, len)) {
-		if (len)
-			*err_ptr = -EFAULT;
-		return sum;
-	}
+	if (!user_access_begin(src, len))
+		return 0;
 	ret = csum_partial_copy_generic((__force void *)src, dst,
-					len, sum, err_ptr, NULL);
+					len, ~0U, &err, NULL);
 	user_access_end();
 
-	return ret;
+	return err ? 0 : ret;
 }
 
 /*
@@ -177,23 +174,19 @@ static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
  */
 static inline __wsum csum_and_copy_to_user(const void *src,
 					   void __user *dst,
-					   int len, __wsum sum,
-					   int *err_ptr)
+					   int len)
 {
 	__wsum ret;
+	int err = 0;
 
 	might_sleep();
-	if (user_access_begin(dst, len)) {
-		ret = csum_partial_copy_generic(src, (__force void *)dst,
-						len, sum, NULL, err_ptr);
-		user_access_end();
-		return ret;
-	}
+	if (!user_access_begin(dst, len))
+		return 0;
 
-	if (len)
-		*err_ptr = -EFAULT;
-
-	return (__force __wsum)-1; /* invalid checksum */
+	ret = csum_partial_copy_generic(src, (__force void *)dst,
+					len, ~0U, NULL, &err);
+	user_access_end();
+	return err ? 0 : ret;
 }
 
 #endif /* _ASM_X86_CHECKSUM_32_H */
diff --git a/arch/x86/include/asm/checksum_64.h b/arch/x86/include/asm/checksum_64.h
index 5339f5dfc776..9af3aed54c6b 100644
--- a/arch/x86/include/asm/checksum_64.h
+++ b/arch/x86/include/asm/checksum_64.h
@@ -135,10 +135,8 @@ extern __visible __wsum csum_partial_copy_generic(const void *src, const void *d
 					int *src_err_ptr, int *dst_err_ptr);
 
 
-extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
-					  int len, __wsum isum, int *errp);
-extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
-					int len, __wsum isum, int *errp);
+extern __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len);
+extern __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len);
 extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);
 
 /**
diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c
index 245f929a1c2c..ae2fb87e2274 100644
--- a/arch/x86/lib/csum-wrappers_64.c
+++ b/arch/x86/lib/csum-wrappers_64.c
@@ -22,13 +22,15 @@
  */
 __wsum
 csum_and_copy_from_user(const void __user *src, void *dst,
-			    int len, __wsum isum, int *errp)
+			    int len)
 {
+	int err = 0;
+	__wsum isum = ~0U;
+
 	might_sleep();
-	*errp = 0;
 
 	if (!user_access_begin(src, len))
-		goto out_err;
+		return 0;
 
 	/*
 	 * Why 6, not 7? To handle odd addresses aligned we
@@ -53,20 +55,15 @@ csum_and_copy_from_user(const void __user *src, void *dst,
 		}
 	}
 	isum = csum_partial_copy_generic((__force const void *)src,
-				dst, len, isum, errp, NULL);
+				dst, len, isum, &err, NULL);
 	user_access_end();
-	if (unlikely(*errp))
-		goto out_err;
-
+	if (unlikely(err))
+		isum = 0;
 	return isum;
 
 out:
 	user_access_end();
-out_err:
-	*errp = -EFAULT;
-	memset(dst, 0, len);
-
-	return isum;
+	return 0;
 }
 EXPORT_SYMBOL(csum_and_copy_from_user);
 
@@ -83,16 +80,15 @@ EXPORT_SYMBOL(csum_and_copy_from_user);
  */
 __wsum
 csum_and_copy_to_user(const void *src, void __user *dst,
-			  int len, __wsum isum, int *errp)
+			  int len)
 {
-	__wsum ret;
+	__wsum ret, isum = ~0U;
+	int err = 0;
 
 	might_sleep();
 
-	if (!user_access_begin(dst, len)) {
-		*errp = -EFAULT;
+	if (!user_access_begin(dst, len))
 		return 0;
-	}
 
 	if (unlikely((unsigned long)dst & 6)) {
 		while (((unsigned long)dst & 6) && len >= 2) {
@@ -107,15 +103,13 @@ csum_and_copy_to_user(const void *src, void __user *dst,
 		}
 	}
 
-	*errp = 0;
 	ret = csum_partial_copy_generic(src, (void __force *)dst,
-					len, isum, NULL, errp);
+					len, isum, NULL, &err);
 	user_access_end();
-	return ret;
+	return err ? 0 : ret;
 out:
 	user_access_end();
-	*errp = -EFAULT;
-	return isum;
+	return 0;
 }
 EXPORT_SYMBOL(csum_and_copy_to_user);
 
diff --git a/arch/x86/um/asm/checksum_32.h b/arch/x86/um/asm/checksum_32.h
index b9ac7c9eb72c..0b13c2947ad1 100644
--- a/arch/x86/um/asm/checksum_32.h
+++ b/arch/x86/um/asm/checksum_32.h
@@ -35,27 +35,4 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 	return csum_fold(sum);
 }
 
-/*
- *	Copy and checksum to user
- */
-#define HAVE_CSUM_COPY_USER
-static __inline__ __wsum csum_and_copy_to_user(const void *src,
-						     void __user *dst,
-						     int len, __wsum sum, int *err_ptr)
-{
-	if (access_ok(dst, len)) {
-		if (copy_to_user(dst, src, len)) {
-			*err_ptr = -EFAULT;
-			return (__force __wsum)-1;
-		}
-
-		return csum_partial(src, len, sum);
-	}
-
-	if (len)
-		*err_ptr = -EFAULT;
-
-	return (__force __wsum)-1; /* invalid checksum */
-}
-
 #endif
diff --git a/arch/xtensa/include/asm/checksum.h b/arch/xtensa/include/asm/checksum.h
index dc09448935bf..fe78fba7bd64 100644
--- a/arch/xtensa/include/asm/checksum.h
+++ b/arch/xtensa/include/asm/checksum.h
@@ -55,14 +55,16 @@ __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
 __wsum csum_and_copy_from_user(const void __user *src, void *dst,
-				   int len, __wsum sum, int *err_ptr)
+				   int len)
 {
-	if (access_ok(src, len))
-		return csum_partial_copy_generic((__force const void *)src, dst,
-					len, sum, err_ptr, NULL);
-	if (len)
-		*err_ptr = -EFAULT;
-	return sum;
+	int err = 0;
+
+	if (!access_ok(src, len))
+		return 0;
+
+	sum = csum_partial_copy_generic((__force const void *)src, dst,
+					len, ~0U, &err, NULL);
+	return err ? 0 : sum;
 }
 
 /*
@@ -243,15 +245,15 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
  */
 #define HAVE_CSUM_COPY_USER
 static __inline__ __wsum csum_and_copy_to_user(const void *src,
-					       void __user *dst, int len,
-					       __wsum sum, int *err_ptr)
+					       void __user *dst, int len)
 {
-	if (access_ok(dst, len))
-		return csum_partial_copy_generic(src,dst,len,sum,NULL,err_ptr);
+	int err = 0;
+	__wsum sum = ~0U;
 
-	if (len)
-		*err_ptr = -EFAULT;
+	if (!access_ok(dst, len))
+		return 0;
 
-	return (__force __wsum)-1; /* invalid checksum */
+	sum = csum_partial_copy_generic(src,dst,len,sum,NULL,&err);
+	return err ? 0 : sum;
 }
 #endif
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 1029191986e3..0d05b9e8690b 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -24,26 +24,23 @@
 #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
 __wsum csum_and_copy_from_user (const void __user *src, void *dst,
-				      int len, __wsum sum, int *err_ptr)
+				      int len)
 {
 	if (copy_from_user(dst, src, len))
-		*err_ptr = -EFAULT;
-	return csum_partial(dst, len, sum);
+		return 0;
+	return csum_partial(dst, len, ~0U);
 }
 #endif
 
 #ifndef HAVE_CSUM_COPY_USER
 static __inline__ __wsum csum_and_copy_to_user
-(const void *src, void __user *dst, int len, __wsum sum, int *err_ptr)
+(const void *src, void __user *dst, int len)
 {
-	sum = csum_partial(src, len, sum);
+	__wsum sum = csum_partial(src, len, ~0U);
 
 	if (copy_to_user(dst, src, len) == 0)
 		return sum;
-	if (len)
-		*err_ptr = -EFAULT;
-
-	return (__force __wsum)-1; /* invalid checksum */
+	return 0;
 }
 #endif
 
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 437fbc14c972..ccb247faf79b 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1449,15 +1449,14 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
 		return 0;
 	}
 	iterate_and_advance(i, bytes, v, ({
-		int err = 0;
 		next = csum_and_copy_from_user(v.iov_base,
 					       (to += v.iov_len) - v.iov_len,
-					       v.iov_len, ~0U, &err);
-		if (!err) {
+					       v.iov_len);
+		if (next) {
 			sum = csum_block_add(sum, next, off);
 			off += v.iov_len;
 		}
-		err ? v.iov_len : 0;
+		next ? 0 : v.iov_len;
 	}), ({
 		char *p = kmap_atomic(v.bv_page);
 		sum = csum_and_memcpy((to += v.bv_len) - v.bv_len,
@@ -1491,11 +1490,10 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
 	if (unlikely(i->count < bytes))
 		return false;
 	iterate_all_kinds(i, bytes, v, ({
-		int err = 0;
 		next = csum_and_copy_from_user(v.iov_base,
 					       (to += v.iov_len) - v.iov_len,
-					       v.iov_len, ~0U, &err);
-		if (err)
+					       v.iov_len);
+		if (!next)
 			return false;
 		sum = csum_block_add(sum, next, off);
 		off += v.iov_len;
@@ -1537,15 +1535,14 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump,
 		return 0;
 	}
 	iterate_and_advance(i, bytes, v, ({
-		int err = 0;
 		next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
 					     v.iov_base,
-					     v.iov_len, ~0U, &err);
-		if (!err) {
+					     v.iov_len);
+		if (next) {
 			sum = csum_block_add(sum, next, off);
 			off += v.iov_len;
 		}
-		err ? v.iov_len : 0;
+		next ? 0 : v.iov_len;
 	}), ({
 		char *p = kmap_atomic(v.bv_page);
 		sum = csum_and_memcpy(p + v.bv_offset,

From b712139543af98a91300c4e923b85d311cc77c44 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 12 Jul 2020 22:55:27 -0400
Subject: [PATCH 07/19] alpha: propagate the calling convention changes down to
 csum_partial_copy.c helpers

get rid of set_fs() in csum_partial_copy_nocheck(), while we are at it -
just take the part of csum_and_copy_from_user() sans the access_ok() check
into a helper function and have csum_partial_copy_nocheck() call that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/alpha/lib/csum_partial_copy.c | 159 +++++++++++++----------------
 1 file changed, 70 insertions(+), 89 deletions(-)

diff --git a/arch/alpha/lib/csum_partial_copy.c b/arch/alpha/lib/csum_partial_copy.c
index 3c0e89c39ddb..dc68efbe9367 100644
--- a/arch/alpha/lib/csum_partial_copy.c
+++ b/arch/alpha/lib/csum_partial_copy.c
@@ -39,12 +39,11 @@ __asm__ __volatile__("insql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
 #define insqh(x,y,z) \
 __asm__ __volatile__("insqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
 
-
-#define __get_user_u(x,ptr)				\
+#define __get_word(insn,x,ptr)				\
 ({							\
 	long __guu_err;					\
 	__asm__ __volatile__(				\
-	"1:	ldq_u %0,%2\n"				\
+	"1:	"#insn" %0,%2\n"			\
 	"2:\n"						\
 	EXC(1b,2b,%0,%1)				\
 		: "=r"(x), "=r"(__guu_err)		\
@@ -52,19 +51,6 @@ __asm__ __volatile__("insqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
 	__guu_err;					\
 })
 
-#define __put_user_u(x,ptr)				\
-({							\
-	long __puu_err;					\
-	__asm__ __volatile__(				\
-	"1:	stq_u %2,%1\n"				\
-	"2:\n"						\
-	EXC(1b,2b,$31,%0)				\
-		: "=r"(__puu_err)			\
-		: "m"(__m(addr)), "rJ"(x), "0"(0));	\
-	__puu_err;					\
-})
-
-
 static inline unsigned short from64to16(unsigned long x)
 {
 	/* Using extract instructions is a bit more efficient
@@ -95,15 +81,15 @@ static inline unsigned short from64to16(unsigned long x)
  */
 static inline unsigned long
 csum_partial_cfu_aligned(const unsigned long __user *src, unsigned long *dst,
-			 long len, unsigned long checksum,
-			 int *errp)
+			 long len)
 {
+	unsigned long checksum = ~0U;
 	unsigned long carry = 0;
-	int err = 0;
 
 	while (len >= 0) {
 		unsigned long word;
-		err |= __get_user(word, src);
+		if (__get_word(ldq, word, src))
+			return 0;
 		checksum += carry;
 		src++;
 		checksum += word;
@@ -116,7 +102,8 @@ csum_partial_cfu_aligned(const unsigned long __user *src, unsigned long *dst,
 	checksum += carry;
 	if (len) {
 		unsigned long word, tmp;
-		err |= __get_user(word, src);
+		if (__get_word(ldq, word, src))
+			return 0;
 		tmp = *dst;
 		mskql(word, len, word);
 		checksum += word;
@@ -125,7 +112,6 @@ csum_partial_cfu_aligned(const unsigned long __user *src, unsigned long *dst,
 		*dst = word | tmp;
 		checksum += carry;
 	}
-	if (err && errp) *errp = err;
 	return checksum;
 }
 
@@ -137,20 +123,21 @@ static inline unsigned long
 csum_partial_cfu_dest_aligned(const unsigned long __user *src,
 			      unsigned long *dst,
 			      unsigned long soff,
-			      long len, unsigned long checksum,
-			      int *errp)
+			      long len)
 {
 	unsigned long first;
 	unsigned long word, carry;
 	unsigned long lastsrc = 7+len+(unsigned long)src;
-	int err = 0;
+	unsigned long checksum = ~0U;
 
-	err |= __get_user_u(first,src);
+	if (__get_word(ldq_u, first,src))
+		return 0;
 	carry = 0;
 	while (len >= 0) {
 		unsigned long second;
 
-		err |= __get_user_u(second, src+1);
+		if (__get_word(ldq_u, second, src+1))
+			return 0;
 		extql(first, soff, word);
 		len -= 8;
 		src++;
@@ -168,7 +155,8 @@ csum_partial_cfu_dest_aligned(const unsigned long __user *src,
 	if (len) {
 		unsigned long tmp;
 		unsigned long second;
-		err |= __get_user_u(second, lastsrc);
+		if (__get_word(ldq_u, second, lastsrc))
+			return 0;
 		tmp = *dst;
 		extql(first, soff, word);
 		extqh(second, soff, first);
@@ -180,7 +168,6 @@ csum_partial_cfu_dest_aligned(const unsigned long __user *src,
 		*dst = word | tmp;
 		checksum += carry;
 	}
-	if (err && errp) *errp = err;
 	return checksum;
 }
 
@@ -191,18 +178,18 @@ static inline unsigned long
 csum_partial_cfu_src_aligned(const unsigned long __user *src,
 			     unsigned long *dst,
 			     unsigned long doff,
-			     long len, unsigned long checksum,
-			     unsigned long partial_dest,
-			     int *errp)
+			     long len,
+			     unsigned long partial_dest)
 {
 	unsigned long carry = 0;
 	unsigned long word;
 	unsigned long second_dest;
-	int err = 0;
+	unsigned long checksum = ~0U;
 
 	mskql(partial_dest, doff, partial_dest);
 	while (len >= 0) {
-		err |= __get_user(word, src);
+		if (__get_word(ldq, word, src))
+			return 0;
 		len -= 8;
 		insql(word, doff, second_dest);
 		checksum += carry;
@@ -216,7 +203,8 @@ csum_partial_cfu_src_aligned(const unsigned long __user *src,
 	len += 8;
 	if (len) {
 		checksum += carry;
-		err |= __get_user(word, src);
+		if (__get_word(ldq, word, src))
+			return 0;
 		mskql(word, len, word);
 		len -= 8;
 		checksum += word;
@@ -237,7 +225,6 @@ csum_partial_cfu_src_aligned(const unsigned long __user *src,
 	stq_u(partial_dest | second_dest, dst);
 out:
 	checksum += carry;
-	if (err && errp) *errp = err;
 	return checksum;
 }
 
@@ -249,23 +236,23 @@ static inline unsigned long
 csum_partial_cfu_unaligned(const unsigned long __user * src,
 			   unsigned long * dst,
 			   unsigned long soff, unsigned long doff,
-			   long len, unsigned long checksum,
-			   unsigned long partial_dest,
-			   int *errp)
+			   long len, unsigned long partial_dest)
 {
 	unsigned long carry = 0;
 	unsigned long first;
 	unsigned long lastsrc;
-	int err = 0;
+	unsigned long checksum = ~0U;
 
-	err |= __get_user_u(first, src);
+	if (__get_word(ldq_u, first, src))
+		return 0;
 	lastsrc = 7+len+(unsigned long)src;
 	mskql(partial_dest, doff, partial_dest);
 	while (len >= 0) {
 		unsigned long second, word;
 		unsigned long second_dest;
 
-		err |= __get_user_u(second, src+1);
+		if (__get_word(ldq_u, second, src+1))
+			return 0;
 		extql(first, soff, word);
 		checksum += carry;
 		len -= 8;
@@ -286,7 +273,8 @@ csum_partial_cfu_unaligned(const unsigned long __user * src,
 		unsigned long second, word;
 		unsigned long second_dest;
 
-		err |= __get_user_u(second, lastsrc);
+		if (__get_word(ldq_u, second, lastsrc))
+			return 0;
 		extql(first, soff, word);
 		extqh(second, soff, first);
 		word |= first;
@@ -307,7 +295,8 @@ csum_partial_cfu_unaligned(const unsigned long __user * src,
 		unsigned long second, word;
 		unsigned long second_dest;
 
-		err |= __get_user_u(second, lastsrc);
+		if (__get_word(ldq_u, second, lastsrc))
+			return 0;
 		extql(first, soff, word);
 		extqh(second, soff, first);
 		word |= first;
@@ -320,63 +309,55 @@ csum_partial_cfu_unaligned(const unsigned long __user * src,
 		stq_u(partial_dest | word | second_dest, dst);
 		checksum += carry;
 	}
-	if (err && errp) *errp = err;
 	return checksum;
 }
 
+static __wsum __csum_and_copy(const void __user *src, void *dst, int len)
+{
+	unsigned long soff = 7 & (unsigned long) src;
+	unsigned long doff = 7 & (unsigned long) dst;
+	unsigned long checksum;
+
+	if (!doff) {
+		if (!soff)
+			checksum = csum_partial_cfu_aligned(
+				(const unsigned long __user *) src,
+				(unsigned long *) dst, len-8);
+		else
+			checksum = csum_partial_cfu_dest_aligned(
+				(const unsigned long __user *) src,
+				(unsigned long *) dst,
+				soff, len-8);
+	} else {
+		unsigned long partial_dest;
+		ldq_u(partial_dest, dst);
+		if (!soff)
+			checksum = csum_partial_cfu_src_aligned(
+				(const unsigned long __user *) src,
+				(unsigned long *) dst,
+				doff, len-8, partial_dest);
+		else
+			checksum = csum_partial_cfu_unaligned(
+				(const unsigned long __user *) src,
+				(unsigned long *) dst,
+				soff, doff, len-8, partial_dest);
+	}
+	return (__force __wsum)from64to16 (checksum);
+}
+
 __wsum
 csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	unsigned long checksum = ~0U;
-	unsigned long soff = 7 & (unsigned long) src;
-	unsigned long doff = 7 & (unsigned long) dst;
-	int err = 0;
-
-	if (len) {
-		if (!access_ok(src, len))
-			return 0;
-		if (!doff) {
-			if (!soff)
-				checksum = csum_partial_cfu_aligned(
-					(const unsigned long __user *) src,
-					(unsigned long *) dst,
-					len-8, checksum, &err);
-			else
-				checksum = csum_partial_cfu_dest_aligned(
-					(const unsigned long __user *) src,
-					(unsigned long *) dst,
-					soff, len-8, checksum, &err);
-		} else {
-			unsigned long partial_dest;
-			ldq_u(partial_dest, dst);
-			if (!soff)
-				checksum = csum_partial_cfu_src_aligned(
-					(const unsigned long __user *) src,
-					(unsigned long *) dst,
-					doff, len-8, checksum,
-					partial_dest, &err);
-			else
-				checksum = csum_partial_cfu_unaligned(
-					(const unsigned long __user *) src,
-					(unsigned long *) dst,
-					soff, doff, len-8, checksum,
-					partial_dest, &err);
-		}
-		checksum = err ? 0 : from64to16 (checksum);
-	}
-	return (__force __wsum)checksum;
+	if (!access_ok(src, len))
+		return 0;
+	return __csum_and_copy(src, dst, len);
 }
 EXPORT_SYMBOL(csum_and_copy_from_user);
 
 __wsum
 csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	__wsum checksum;
-	mm_segment_t oldfs = get_fs();
-	set_fs(KERNEL_DS);
-	checksum = csum_and_copy_from_user((__force const void __user *)src,
+	return __csum_and_copy((__force const void __user *)src,
 						dst, len);
-	set_fs(oldfs);
-	return checksum;
 }
 EXPORT_SYMBOL(csum_partial_copy_nocheck);

From 1d60be3c25edf4b9554fdb02aa6fb6fd75695aa7 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 12 Jul 2020 22:56:34 -0400
Subject: [PATCH 08/19] arm: propagate the calling convention changes down to
 csum_partial_copy_from_user()

... and get rid of the "clean the destination on error" crap.
Simplifies the fault handlers and the function itself...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/arm/include/asm/checksum.h       |  7 ++-----
 arch/arm/lib/csumpartialcopy.S        |  1 -
 arch/arm/lib/csumpartialcopygeneric.S |  1 +
 arch/arm/lib/csumpartialcopyuser.S    | 26 ++++++--------------------
 4 files changed, 9 insertions(+), 26 deletions(-)

diff --git a/arch/arm/include/asm/checksum.h b/arch/arm/include/asm/checksum.h
index 1601c132b064..f0f54aef3724 100644
--- a/arch/arm/include/asm/checksum.h
+++ b/arch/arm/include/asm/checksum.h
@@ -38,20 +38,17 @@ __wsum
 csum_partial_copy_nocheck(const void *src, void *dst, int len);
 
 __wsum
-csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr);
+csum_partial_copy_from_user(const void __user *src, void *dst, int len);
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 #define _HAVE_ARCH_CSUM_AND_COPY
 static inline
 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	int err = 0;
-
 	if (!access_ok(src, len))
 		return 0;
 
-	sum = csum_partial_copy_from_user(src, dst, len, ~0U, &err);
-	return err ? 0 : sum;
+	return csum_partial_copy_from_user(src, dst, len);
 }
 
 /*
diff --git a/arch/arm/lib/csumpartialcopy.S b/arch/arm/lib/csumpartialcopy.S
index aab914fbc86b..1ca6aadd649c 100644
--- a/arch/arm/lib/csumpartialcopy.S
+++ b/arch/arm/lib/csumpartialcopy.S
@@ -16,7 +16,6 @@
 
 		.macro	save_regs
 		stmfd	sp!, {r1, r4 - r8, lr}
-		mov	r3, #0
 		.endm
 
 		.macro	load_regs
diff --git a/arch/arm/lib/csumpartialcopygeneric.S b/arch/arm/lib/csumpartialcopygeneric.S
index 0b706a39a677..0fd5c10e90a7 100644
--- a/arch/arm/lib/csumpartialcopygeneric.S
+++ b/arch/arm/lib/csumpartialcopygeneric.S
@@ -86,6 +86,7 @@ sum	.req	r3
 
 FN_ENTRY
 		save_regs
+		mov	sum, #-1
 
 		cmp	len, #8			@ Ensure that we have at least
 		blo	.Lless8			@ 8 bytes to copy.
diff --git a/arch/arm/lib/csumpartialcopyuser.S b/arch/arm/lib/csumpartialcopyuser.S
index 6bd3a93eaa3c..6928781e6bee 100644
--- a/arch/arm/lib/csumpartialcopyuser.S
+++ b/arch/arm/lib/csumpartialcopyuser.S
@@ -62,9 +62,9 @@
 
 /*
  * unsigned int
- * csum_partial_copy_from_user(const char *src, char *dst, int len, int sum, int *err_ptr)
- *  r0 = src, r1 = dst, r2 = len, r3 = sum, [sp] = *err_ptr
- *  Returns : r0 = checksum, [[sp, #0], #0] = 0 or -EFAULT
+ * csum_partial_copy_from_user(const char *src, char *dst, int len)
+ *  r0 = src, r1 = dst, r2 = len
+ *  Returns : r0 = checksum or 0
  */
 
 #define FN_ENTRY	ENTRY(csum_partial_copy_from_user)
@@ -73,25 +73,11 @@
 #include "csumpartialcopygeneric.S"
 
 /*
- * FIXME: minor buglet here
- * We don't return the checksum for the data present in the buffer.  To do
- * so properly, we would have to add in whatever registers were loaded before
- * the fault, which, with the current asm above is not predictable.
+ * We report fault by returning 0 csum - impossible in normal case, since
+ * we start with 0xffffffff for initial sum.
  */
 		.pushsection .text.fixup,"ax"
 		.align	4
-9001:		mov	r4, #-EFAULT
-#ifdef CONFIG_CPU_SW_DOMAIN_PAN
-		ldr	r5, [sp, #9*4]		@ *err_ptr
-#else
-		ldr	r5, [sp, #8*4]		@ *err_ptr
-#endif
-		str	r4, [r5]
-		ldmia	sp, {r1, r2}		@ retrieve dst, len
-		add	r2, r2, r1
-		mov	r0, #0			@ zero the buffer
-9002:		teq	r2, r1
-		strbne	r0, [r1], #1
-		bne	9002b
+9001:		mov	r0, #0
 		load_regs
 		.popsection

From 66aa38801a5d1ea58b208d9d41374b9fac2088d3 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 12 Jul 2020 23:01:10 -0400
Subject: [PATCH 09/19] m68k: get rid of zeroing destination on error in
 csum_and_copy_from_user()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/m68k/lib/checksum.c | 79 ++++++++--------------------------------
 1 file changed, 15 insertions(+), 64 deletions(-)

diff --git a/arch/m68k/lib/checksum.c b/arch/m68k/lib/checksum.c
index 3aeca261f622..7e6afeae6217 100644
--- a/arch/m68k/lib/checksum.c
+++ b/arch/m68k/lib/checksum.c
@@ -236,82 +236,33 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len)
 		"clrl %5\n\t"
 		"addxl %5,%0\n\t"	/* add X bit */
 	     "7:\t"
-		"clrl %5\n"		/* no error - clear return value */
-	     "8:\n"
 		".section .fixup,\"ax\"\n"
 		".even\n"
-		/* If any exception occurs zero out the rest.
-		   Similarities with the code above are intentional :-) */
+		/* If any exception occurs, return 0 */
 	     "90:\t"
-		"clrw %3@+\n\t"
-		"movel %1,%4\n\t"
-		"lsrl #5,%1\n\t"
-		"jeq 1f\n\t"
-		"subql #1,%1\n"
-	     "91:\t"
-		"clrl %3@+\n"
-	     "92:\t"
-		"clrl %3@+\n"
-	     "93:\t"
-		"clrl %3@+\n"
-	     "94:\t"
-		"clrl %3@+\n"
-	     "95:\t"
-		"clrl %3@+\n"
-	     "96:\t"
-		"clrl %3@+\n"
-	     "97:\t"
-		"clrl %3@+\n"
-	     "98:\t"
-		"clrl %3@+\n\t"
-		"dbra %1,91b\n\t"
-		"clrw %1\n\t"
-		"subql #1,%1\n\t"
-		"jcc 91b\n"
-	     "1:\t"
-		"movel %4,%1\n\t"
-		"andw #0x1c,%4\n\t"
-		"jeq 1f\n\t"
-		"lsrw #2,%4\n\t"
-		"subqw #1,%4\n"
-	     "99:\t"
-		"clrl %3@+\n\t"
-		"dbra %4,99b\n\t"
-	     "1:\t"
-		"andw #3,%1\n\t"
-		"jeq 9f\n"
-	     "100:\t"
-		"clrw %3@+\n\t"
-		"tstw %1\n\t"
-		"jeq 9f\n"
-	     "101:\t"
-		"clrb %3@+\n"
-	     "9:\t"
-#define STR(X) STR1(X)
-#define STR1(X) #X
-		"moveq #-" STR(EFAULT) ",%5\n\t"
-		"jra 8b\n"
+		"clrl %0\n"
+		"jra 7b\n"
 		".previous\n"
 		".section __ex_table,\"a\"\n"
 		".long 10b,90b\n"
-		".long 11b,91b\n"
-		".long 12b,92b\n"
-		".long 13b,93b\n"
-		".long 14b,94b\n"
-		".long 15b,95b\n"
-		".long 16b,96b\n"
-		".long 17b,97b\n"
-		".long 18b,98b\n"
-		".long 19b,99b\n"
-		".long 20b,100b\n"
-		".long 21b,101b\n"
+		".long 11b,90b\n"
+		".long 12b,90b\n"
+		".long 13b,90b\n"
+		".long 14b,90b\n"
+		".long 15b,90b\n"
+		".long 16b,90b\n"
+		".long 17b,90b\n"
+		".long 18b,90b\n"
+		".long 19b,90b\n"
+		".long 20b,90b\n"
+		".long 21b,90b\n"
 		".previous"
 		: "=d" (sum), "=d" (len), "=a" (src), "=a" (dst),
 		  "=&d" (tmp1), "=d" (tmp2)
 		: "0" (sum), "1" (len), "2" (src), "3" (dst)
 	    );
 
-	return tmp2 ? 0 : sum;
+	return sum;
 }
 
 EXPORT_SYMBOL(csum_and_copy_from_user);

From dc16c8a9ce980d03cfeedbc2559744140d134130 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 12 Jul 2020 23:05:44 -0400
Subject: [PATCH 10/19] sh: propage the calling conventions change down to
 csum_partial_copy_generic()

... and get rid of zeroing destination on error there.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/sh/include/asm/checksum_32.h |  20 +----
 arch/sh/lib/checksum.S            | 119 +++++++++---------------------
 2 files changed, 39 insertions(+), 100 deletions(-)

diff --git a/arch/sh/include/asm/checksum_32.h b/arch/sh/include/asm/checksum_32.h
index a08e8eb924ed..1a391e3a7659 100644
--- a/arch/sh/include/asm/checksum_32.h
+++ b/arch/sh/include/asm/checksum_32.h
@@ -30,9 +30,7 @@ asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
  * better 64-bit) boundary
  */
 
-asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
-					    int len, __wsum sum,
-					    int *src_err_ptr, int *dst_err_ptr);
+asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
 
 #define _HAVE_ARCH_CSUM_AND_COPY
 /*
@@ -45,21 +43,16 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
 static inline
 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
+	return csum_partial_copy_generic(src, dst, len);
 }
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	int err = 0;
-	__wsum sum = ~0U;
-
 	if (!access_ok(src, len))
 		return 0;
-	sum = csum_partial_copy_generic((__force const void *)src, dst,
-					len, sum, &err, NULL);
-	return err ? 0 : sum;
+	return csum_partial_copy_generic((__force const void *)src, dst, len);
 }
 
 /*
@@ -202,13 +195,8 @@ static inline __wsum csum_and_copy_to_user(const void *src,
 					   void __user *dst,
 					   int len)
 {
-	int err = 0;
-	__wsum sum = ~0U;
-
 	if (!access_ok(dst, len))
 		return 0;
-	sum = csum_partial_copy_generic((__force const void *)src,
-						dst, len, sum, NULL, &err);
-	return err ? 0 : sum;
+	return csum_partial_copy_generic((__force const void *)src, dst, len);
 }
 #endif /* __ASM_SH_CHECKSUM_H */
diff --git a/arch/sh/lib/checksum.S b/arch/sh/lib/checksum.S
index 97b5c2d9fec4..3e07074e0098 100644
--- a/arch/sh/lib/checksum.S
+++ b/arch/sh/lib/checksum.S
@@ -173,47 +173,27 @@ ENTRY(csum_partial)
 	 mov	r6, r0
 
 /*
-unsigned int csum_partial_copy_generic (const char *src, char *dst, int len, 
-					int sum, int *src_err_ptr, int *dst_err_ptr)
+unsigned int csum_partial_copy_generic (const char *src, char *dst, int len)
  */ 
 
 /*
- * Copy from ds while checksumming, otherwise like csum_partial
- *
- * The macros SRC and DST specify the type of access for the instruction.
- * thus we can call a custom exception handler for all access types.
- *
- * FIXME: could someone double-check whether I haven't mixed up some SRC and
- *	  DST definitions? It's damn hard to trigger all cases.  I hope I got
- *	  them all but there's no guarantee.
+ * Copy from ds while checksumming, otherwise like csum_partial with initial
+ * sum being ~0U
  */
 
-#define SRC(...)			\
+#define EXC(...)			\
 	9999: __VA_ARGS__ ;		\
 	.section __ex_table, "a";	\
 	.long 9999b, 6001f	;	\
 	.previous
 
-#define DST(...)			\
-	9999: __VA_ARGS__ ;		\
-	.section __ex_table, "a";	\
-	.long 9999b, 6002f	;	\
-	.previous
-
 !
 ! r4:	const char *SRC
 ! r5:	char *DST
 ! r6:	int LEN
-! r7:	int SUM
-!
-! on stack:
-! int *SRC_ERR_PTR
-! int *DST_ERR_PTR
 !
 ENTRY(csum_partial_copy_generic)
-	mov.l	r5,@-r15
-	mov.l	r6,@-r15
-
+	mov	#-1,r7
 	mov	#3,r0		! Check src and dest are equally aligned
 	mov	r4,r1
 	and	r0,r1
@@ -243,11 +223,11 @@ ENTRY(csum_partial_copy_generic)
 	clrt
 	.align	2
 5:
-SRC(	mov.b	@r4+,r1 	)
-SRC(	mov.b	@r4+,r0		)
+EXC(	mov.b	@r4+,r1 	)
+EXC(	mov.b	@r4+,r0		)
 	extu.b	r1,r1
-DST(	mov.b	r1,@r5		)
-DST(	mov.b	r0,@(1,r5)	)
+EXC(	mov.b	r1,@r5		)
+EXC(	mov.b	r0,@(1,r5)	)
 	extu.b	r0,r0
 	add	#2,r5
 
@@ -276,8 +256,8 @@ DST(	mov.b	r0,@(1,r5)	)
 	! Handle first two bytes as a special case
 	.align	2
 1:	
-SRC(	mov.w	@r4+,r0		)
-DST(	mov.w	r0,@r5		)
+EXC(	mov.w	@r4+,r0		)
+EXC(	mov.w	r0,@r5		)
 	add	#2,r5
 	extu.w	r0,r0
 	addc	r0,r7
@@ -292,32 +272,32 @@ DST(	mov.w	r0,@r5		)
 	 clrt
 	.align	2
 1:	
-SRC(	mov.l	@r4+,r0		)
-SRC(	mov.l	@r4+,r1		)
+EXC(	mov.l	@r4+,r0		)
+EXC(	mov.l	@r4+,r1		)
 	addc	r0,r7
-DST(	mov.l	r0,@r5		)
-DST(	mov.l	r1,@(4,r5)	)
+EXC(	mov.l	r0,@r5		)
+EXC(	mov.l	r1,@(4,r5)	)
 	addc	r1,r7
 
-SRC(	mov.l	@r4+,r0		)
-SRC(	mov.l	@r4+,r1		)
+EXC(	mov.l	@r4+,r0		)
+EXC(	mov.l	@r4+,r1		)
 	addc	r0,r7
-DST(	mov.l	r0,@(8,r5)	)
-DST(	mov.l	r1,@(12,r5)	)
+EXC(	mov.l	r0,@(8,r5)	)
+EXC(	mov.l	r1,@(12,r5)	)
 	addc	r1,r7
 
-SRC(	mov.l	@r4+,r0 	)
-SRC(	mov.l	@r4+,r1		)
+EXC(	mov.l	@r4+,r0 	)
+EXC(	mov.l	@r4+,r1		)
 	addc	r0,r7
-DST(	mov.l	r0,@(16,r5)	)
-DST(	mov.l	r1,@(20,r5)	)
+EXC(	mov.l	r0,@(16,r5)	)
+EXC(	mov.l	r1,@(20,r5)	)
 	addc	r1,r7
 
-SRC(	mov.l	@r4+,r0		)
-SRC(	mov.l	@r4+,r1		)
+EXC(	mov.l	@r4+,r0		)
+EXC(	mov.l	@r4+,r1		)
 	addc	r0,r7
-DST(	mov.l	r0,@(24,r5)	)
-DST(	mov.l	r1,@(28,r5)	)
+EXC(	mov.l	r0,@(24,r5)	)
+EXC(	mov.l	r1,@(28,r5)	)
 	addc	r1,r7
 	add	#32,r5
 	movt	r0
@@ -335,9 +315,9 @@ DST(	mov.l	r1,@(28,r5)	)
 	 clrt
 	shlr2	r6
 3:	
-SRC(	mov.l	@r4+,r0	)
+EXC(	mov.l	@r4+,r0	)
 	addc	r0,r7
-DST(	mov.l	r0,@r5	)
+EXC(	mov.l	r0,@r5	)
 	add	#4,r5
 	movt	r0
 	dt	r6
@@ -353,8 +333,8 @@ DST(	mov.l	r0,@r5	)
 	mov	#2,r1
 	cmp/hs	r1,r6
 	bf	5f
-SRC(	mov.w	@r4+,r0	)
-DST(	mov.w	r0,@r5	)
+EXC(	mov.w	@r4+,r0	)
+EXC(	mov.w	r0,@r5	)
 	extu.w	r0,r0
 	add	#2,r5
 	cmp/eq	r1,r6
@@ -363,8 +343,8 @@ DST(	mov.w	r0,@r5	)
 	shll16	r0
 	addc	r0,r7
 5:	
-SRC(	mov.b	@r4+,r0	)
-DST(	mov.b	r0,@r5	)
+EXC(	mov.b	@r4+,r0	)
+EXC(	mov.b	r0,@r5	)
 	extu.b	r0,r0
 #ifndef	__LITTLE_ENDIAN__
 	shll8	r0
@@ -373,42 +353,13 @@ DST(	mov.b	r0,@r5	)
 	mov	#0,r0
 	addc	r0,r7
 7:
-5000:
 
 # Exception handler:
 .section .fixup, "ax"							
 
 6001:
-	mov.l	@(8,r15),r0			! src_err_ptr
-	mov	#-EFAULT,r1
-	mov.l	r1,@r0
-
-	! zero the complete destination - computing the rest
-	! is too much work 
-	mov.l	@(4,r15),r5		! dst
-	mov.l	@r15,r6			! len
-	mov	#0,r7
-1:	mov.b	r7,@r5
-	dt	r6
-	bf/s	1b
-	 add	#1,r5
-	mov.l	8000f,r0
-	jmp	@r0
-	 nop
-	.align	2
-8000:	.long	5000b
-
-6002:
-	mov.l	@(12,r15),r0			! dst_err_ptr
-	mov	#-EFAULT,r1
-	mov.l	r1,@r0
-	mov.l	8001f,r0
-	jmp	@r0
-	 nop
-	.align	2
-8001:	.long	5000b
-
+	rts
+	 mov	#0,r0
 .previous
-	add	#8,r15
 	rts
 	 mov	r7,r0

From e8b95089990ceac4e5197db3c03737bf569f5081 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 12 Jul 2020 23:53:10 -0400
Subject: [PATCH 11/19] i386: propagate the calling conventions change down to
 csum_partial_copy_generic()

... and don't bother zeroing destination on error

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/x86/include/asm/checksum_32.h |  18 ++---
 arch/x86/lib/checksum_32.S         | 117 ++++++++++-------------------
 2 files changed, 47 insertions(+), 88 deletions(-)

diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h
index 5948cde9e4ad..17da95387997 100644
--- a/arch/x86/include/asm/checksum_32.h
+++ b/arch/x86/include/asm/checksum_32.h
@@ -27,9 +27,7 @@ asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
  * better 64-bit) boundary
  */
 
-asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
-					    int len, __wsum sum,
-					    int *src_err_ptr, int *dst_err_ptr);
+asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
 
 /*
  *	Note: when you get a NULL pointer exception here this means someone
@@ -40,23 +38,21 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
  */
 static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
+	return csum_partial_copy_generic(src, dst, len);
 }
 
 static inline __wsum csum_and_copy_from_user(const void __user *src,
 					     void *dst, int len)
 {
 	__wsum ret;
-	int err = 0;
 
 	might_sleep();
 	if (!user_access_begin(src, len))
 		return 0;
-	ret = csum_partial_copy_generic((__force void *)src, dst,
-					len, ~0U, &err, NULL);
+	ret = csum_partial_copy_generic((__force void *)src, dst, len);
 	user_access_end();
 
-	return err ? 0 : ret;
+	return ret;
 }
 
 /*
@@ -177,16 +173,14 @@ static inline __wsum csum_and_copy_to_user(const void *src,
 					   int len)
 {
 	__wsum ret;
-	int err = 0;
 
 	might_sleep();
 	if (!user_access_begin(dst, len))
 		return 0;
 
-	ret = csum_partial_copy_generic(src, (__force void *)dst,
-					len, ~0U, NULL, &err);
+	ret = csum_partial_copy_generic(src, (__force void *)dst, len);
 	user_access_end();
-	return err ? 0 : ret;
+	return ret;
 }
 
 #endif /* _ASM_X86_CHECKSUM_32_H */
diff --git a/arch/x86/lib/checksum_32.S b/arch/x86/lib/checksum_32.S
index d1d768912368..4304320e51f4 100644
--- a/arch/x86/lib/checksum_32.S
+++ b/arch/x86/lib/checksum_32.S
@@ -253,28 +253,17 @@ EXPORT_SYMBOL(csum_partial)
 
 /*
 unsigned int csum_partial_copy_generic (const char *src, char *dst,
-				  int len, int sum, int *src_err_ptr, int *dst_err_ptr)
+				  int len)
  */ 
 
 /*
  * Copy from ds while checksumming, otherwise like csum_partial
- *
- * The macros SRC and DST specify the type of access for the instruction.
- * thus we can call a custom exception handler for all access types.
- *
- * FIXME: could someone double-check whether I haven't mixed up some SRC and
- *	  DST definitions? It's damn hard to trigger all cases.  I hope I got
- *	  them all but there's no guarantee.
  */
 
-#define SRC(y...)			\
+#define EXC(y...)			\
 	9999: y;			\
 	_ASM_EXTABLE_UA(9999b, 6001f)
 
-#define DST(y...)			\
-	9999: y;			\
-	_ASM_EXTABLE_UA(9999b, 6002f)
-
 #ifndef CONFIG_X86_USE_PPRO_CHECKSUM
 
 #define ARGBASE 16		
@@ -285,20 +274,20 @@ SYM_FUNC_START(csum_partial_copy_generic)
 	pushl %edi
 	pushl %esi
 	pushl %ebx
-	movl ARGBASE+16(%esp),%eax	# sum
 	movl ARGBASE+12(%esp),%ecx	# len
 	movl ARGBASE+4(%esp),%esi	# src
 	movl ARGBASE+8(%esp),%edi	# dst
 
+	movl $-1, %eax			# sum
 	testl $2, %edi			# Check alignment. 
 	jz 2f				# Jump if alignment is ok.
 	subl $2, %ecx			# Alignment uses up two bytes.
 	jae 1f				# Jump if we had at least two bytes.
 	addl $2, %ecx			# ecx was < 2.  Deal with it.
 	jmp 4f
-SRC(1:	movw (%esi), %bx	)
+EXC(1:	movw (%esi), %bx	)
 	addl $2, %esi
-DST(	movw %bx, (%edi)	)
+EXC(	movw %bx, (%edi)	)
 	addl $2, %edi
 	addw %bx, %ax	
 	adcl $0, %eax
@@ -306,34 +295,34 @@ DST(	movw %bx, (%edi)	)
 	movl %ecx, FP(%esp)
 	shrl $5, %ecx
 	jz 2f
-	testl %esi, %esi
-SRC(1:	movl (%esi), %ebx	)
-SRC(	movl 4(%esi), %edx	)
+	testl %esi, %esi		# what's wrong with clc?
+EXC(1:	movl (%esi), %ebx	)
+EXC(	movl 4(%esi), %edx	)
 	adcl %ebx, %eax
-DST(	movl %ebx, (%edi)	)
+EXC(	movl %ebx, (%edi)	)
 	adcl %edx, %eax
-DST(	movl %edx, 4(%edi)	)
+EXC(	movl %edx, 4(%edi)	)
 
-SRC(	movl 8(%esi), %ebx	)
-SRC(	movl 12(%esi), %edx	)
+EXC(	movl 8(%esi), %ebx	)
+EXC(	movl 12(%esi), %edx	)
 	adcl %ebx, %eax
-DST(	movl %ebx, 8(%edi)	)
+EXC(	movl %ebx, 8(%edi)	)
 	adcl %edx, %eax
-DST(	movl %edx, 12(%edi)	)
+EXC(	movl %edx, 12(%edi)	)
 
-SRC(	movl 16(%esi), %ebx 	)
-SRC(	movl 20(%esi), %edx	)
+EXC(	movl 16(%esi), %ebx 	)
+EXC(	movl 20(%esi), %edx	)
 	adcl %ebx, %eax
-DST(	movl %ebx, 16(%edi)	)
+EXC(	movl %ebx, 16(%edi)	)
 	adcl %edx, %eax
-DST(	movl %edx, 20(%edi)	)
+EXC(	movl %edx, 20(%edi)	)
 
-SRC(	movl 24(%esi), %ebx	)
-SRC(	movl 28(%esi), %edx	)
+EXC(	movl 24(%esi), %ebx	)
+EXC(	movl 28(%esi), %edx	)
 	adcl %ebx, %eax
-DST(	movl %ebx, 24(%edi)	)
+EXC(	movl %ebx, 24(%edi)	)
 	adcl %edx, %eax
-DST(	movl %edx, 28(%edi)	)
+EXC(	movl %edx, 28(%edi)	)
 
 	lea 32(%esi), %esi
 	lea 32(%edi), %edi
@@ -345,9 +334,9 @@ DST(	movl %edx, 28(%edi)	)
 	andl $0x1c, %edx
 	je 4f
 	shrl $2, %edx			# This clears CF
-SRC(3:	movl (%esi), %ebx	)
+EXC(3:	movl (%esi), %ebx	)
 	adcl %ebx, %eax
-DST(	movl %ebx, (%edi)	)
+EXC(	movl %ebx, (%edi)	)
 	lea 4(%esi), %esi
 	lea 4(%edi), %edi
 	dec %edx
@@ -357,39 +346,24 @@ DST(	movl %ebx, (%edi)	)
 	jz 7f
 	cmpl $2, %ecx
 	jb 5f
-SRC(	movw (%esi), %cx	)
+EXC(	movw (%esi), %cx	)
 	leal 2(%esi), %esi
-DST(	movw %cx, (%edi)	)
+EXC(	movw %cx, (%edi)	)
 	leal 2(%edi), %edi
 	je 6f
 	shll $16,%ecx
-SRC(5:	movb (%esi), %cl	)
-DST(	movb %cl, (%edi)	)
+EXC(5:	movb (%esi), %cl	)
+EXC(	movb %cl, (%edi)	)
 6:	addl %ecx, %eax
 	adcl $0, %eax
 7:
-5000:
 
 # Exception handler:
 .section .fixup, "ax"							
 
 6001:
-	movl ARGBASE+20(%esp), %ebx	# src_err_ptr
-	movl $-EFAULT, (%ebx)
-
-	# zero the complete destination - computing the rest
-	# is too much work 
-	movl ARGBASE+8(%esp), %edi	# dst
-	movl ARGBASE+12(%esp), %ecx	# len
-	xorl %eax,%eax
-	rep ; stosb
-
-	jmp 5000b
-
-6002:
-	movl ARGBASE+24(%esp), %ebx	# dst_err_ptr
-	movl $-EFAULT,(%ebx)
-	jmp 5000b
+	xorl %eax, %eax
+	jmp 7b
 
 .previous
 
@@ -405,14 +379,14 @@ SYM_FUNC_END(csum_partial_copy_generic)
 /* Version for PentiumII/PPro */
 
 #define ROUND1(x) \
-	SRC(movl x(%esi), %ebx	)	;	\
+	EXC(movl x(%esi), %ebx	)	;	\
 	addl %ebx, %eax			;	\
-	DST(movl %ebx, x(%edi)	)	; 
+	EXC(movl %ebx, x(%edi)	)	;
 
 #define ROUND(x) \
-	SRC(movl x(%esi), %ebx	)	;	\
+	EXC(movl x(%esi), %ebx	)	;	\
 	adcl %ebx, %eax			;	\
-	DST(movl %ebx, x(%edi)	)	;
+	EXC(movl %ebx, x(%edi)	)	;
 
 #define ARGBASE 12
 		
@@ -423,7 +397,7 @@ SYM_FUNC_START(csum_partial_copy_generic)
 	movl ARGBASE+4(%esp),%esi	#src
 	movl ARGBASE+8(%esp),%edi	#dst	
 	movl ARGBASE+12(%esp),%ecx	#len
-	movl ARGBASE+16(%esp),%eax	#sum
+	movl $-1, %eax			#sum
 #	movl %ecx, %edx  
 	movl %ecx, %ebx  
 	movl %esi, %edx
@@ -439,7 +413,7 @@ SYM_FUNC_START(csum_partial_copy_generic)
 	JMP_NOSPEC ebx
 1:	addl $64,%esi
 	addl $64,%edi 
-	SRC(movb -32(%edx),%bl)	; SRC(movb (%edx),%bl)
+	EXC(movb -32(%edx),%bl)	; EXC(movb (%edx),%bl)
 	ROUND1(-64) ROUND(-60) ROUND(-56) ROUND(-52)	
 	ROUND (-48) ROUND(-44) ROUND(-40) ROUND(-36)	
 	ROUND (-32) ROUND(-28) ROUND(-24) ROUND(-20)	
@@ -453,29 +427,20 @@ SYM_FUNC_START(csum_partial_copy_generic)
 	jz 7f
 	cmpl $2, %edx
 	jb 5f
-SRC(	movw (%esi), %dx         )
+EXC(	movw (%esi), %dx         )
 	leal 2(%esi), %esi
-DST(	movw %dx, (%edi)         )
+EXC(	movw %dx, (%edi)         )
 	leal 2(%edi), %edi
 	je 6f
 	shll $16,%edx
 5:
-SRC(	movb (%esi), %dl         )
-DST(	movb %dl, (%edi)         )
+EXC(	movb (%esi), %dl         )
+EXC(	movb %dl, (%edi)         )
 6:	addl %edx, %eax
 	adcl $0, %eax
 7:
 .section .fixup, "ax"
-6001:	movl	ARGBASE+20(%esp), %ebx	# src_err_ptr	
-	movl $-EFAULT, (%ebx)
-	# zero the complete destination (computing the rest is too much work)
-	movl ARGBASE+8(%esp),%edi	# dst
-	movl ARGBASE+12(%esp),%ecx	# len
-	xorl %eax,%eax
-	rep; stosb
-	jmp 7b
-6002:	movl ARGBASE+24(%esp), %ebx	# dst_err_ptr
-	movl $-EFAULT, (%ebx)
+6001:	xorl %eax, %eax
 	jmp  7b			
 .previous				
 

From ab5e8b33124468fe9d7d6042de5a9b35414c784e Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 13 Jul 2020 15:12:48 -0400
Subject: [PATCH 12/19] sparc32: propagate the calling conventions change down
 to __csum_partial_copy_sparc_generic()

... and get rid of zeroing the target, etc. on fault.
All exception handlers merge into one; moreover, since we are not
calling lookup_fault() anymore, we don't need the magic with passing
arguments for it from the page fault handler.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/sparc/include/asm/checksum_32.h |  49 +------
 arch/sparc/lib/checksum_32.S         | 202 +++++----------------------
 arch/sparc/mm/fault_32.c             |   6 +-
 3 files changed, 44 insertions(+), 213 deletions(-)

diff --git a/arch/sparc/include/asm/checksum_32.h b/arch/sparc/include/asm/checksum_32.h
index b5873b7b7bf0..d55e480172a6 100644
--- a/arch/sparc/include/asm/checksum_32.h
+++ b/arch/sparc/include/asm/checksum_32.h
@@ -50,9 +50,9 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len)
 
 	__asm__ __volatile__ (
 		"call __csum_partial_copy_sparc_generic\n\t"
-		" mov %6, %%g7\n"
+		" mov -1, %%g7\n"
 	: "=&r" (ret), "=&r" (d), "=&r" (l)
-	: "0" (ret), "1" (d), "2" (l), "r" (0)
+	: "0" (ret), "1" (d), "2" (l)
 	: "o2", "o3", "o4", "o5", "o7",
 	  "g2", "g3", "g4", "g5", "g7",
 	  "memory", "cc");
@@ -61,29 +61,10 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len)
 
 static inline __wsum
 csum_and_copy_from_user(const void __user *src, void *dst, int len)
-  {
-	register unsigned long ret asm("o0") = (unsigned long)src;
-	register char *d asm("o1") = dst;
-	register int l asm("g1") = len;
-	register __wsum s asm("g7") = ~0U;
-	int err = 0;
-
+{
 	if (unlikely(!access_ok(src, len)))
 		return 0;
-
-	__asm__ __volatile__ (
-	".section __ex_table,#alloc\n\t"
-	".align 4\n\t"
-	".word 1f,2\n\t"
-	".previous\n"
-	"1:\n\t"
-	"call __csum_partial_copy_sparc_generic\n\t"
-	" st %8, [%%sp + 64]\n"
-	: "=&r" (ret), "=&r" (d), "=&r" (l), "=&r" (s)
-	: "0" (ret), "1" (d), "2" (l), "3" (s), "r" (&err)
-	: "o2", "o3", "o4", "o5", "o7", "g2", "g3", "g4", "g5",
-	  "cc", "memory");
-	return err ? 0 : (__force __wsum)ret;
+	return csum_partial_copy_nocheck((__force void *)src, dst, len);
 }
 
 #define HAVE_CSUM_COPY_USER
@@ -91,29 +72,9 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len)
 static inline __wsum
 csum_and_copy_to_user(const void *src, void __user *dst, int len)
 {
-	register unsigned long ret asm("o0") = (unsigned long)src;
-	register char __user *d asm("o1") = dst;
-	register int l asm("g1") = len;
-	register __wsum s asm("g7") = ~0U;
-	int err = 0;
-
 	if (!access_ok(dst, len))
 		return 0;
-
-	__asm__ __volatile__ (
-	".section __ex_table,#alloc\n\t"
-	".align 4\n\t"
-	".word 1f,1\n\t"
-	".previous\n"
-	"1:\n\t"
-	"call __csum_partial_copy_sparc_generic\n\t"
-	" st %8, [%%sp + 64]\n"
-	: "=&r" (ret), "=&r" (d), "=&r" (l), "=&r" (s)
-	: "0" (ret), "1" (d), "2" (l), "3" (s), "r" (&err)
-	: "o2", "o3", "o4", "o5", "o7",
-	  "g2", "g3", "g4", "g5",
-	  "cc", "memory");
-	return err ? 0 : (__force __wsum)ret;
+	return csum_partial_copy_nocheck(src, (__force void *)dst, len);
 }
 
 /* ihl is always 5 or greater, almost always is 5, and iph is word aligned
diff --git a/arch/sparc/lib/checksum_32.S b/arch/sparc/lib/checksum_32.S
index 6a5469c97246..7488d130faf7 100644
--- a/arch/sparc/lib/checksum_32.S
+++ b/arch/sparc/lib/checksum_32.S
@@ -144,44 +144,21 @@ cpte:	bne	csum_partial_end_cruft			! yep, handle it
 cpout:	retl						! get outta here
 	 mov	%o2, %o0				! return computed csum
 
-	.globl __csum_partial_copy_start, __csum_partial_copy_end
-__csum_partial_copy_start:
-
 /* Work around cpp -rob */
 #define ALLOC #alloc
 #define EXECINSTR #execinstr
-#define EX(x,y,a,b)				\
-98:     x,y;                                    \
-        .section .fixup,ALLOC,EXECINSTR;	\
-        .align  4;                              \
-99:     ba 30f;                                 \
-         a, b, %o3;                             \
-        .section __ex_table,ALLOC;		\
-        .align  4;                              \
-        .word   98b, 99b;                       \
-        .text;                                  \
-        .align  4
-
-#define EX2(x,y)				\
+#define EX(x,y)					\
 98:     x,y;                                    \
         .section __ex_table,ALLOC;		\
         .align  4;                              \
-        .word   98b, 30f;                       \
+        .word   98b, cc_fault;                   \
         .text;                                  \
         .align  4
 
-#define EX3(x,y)				\
-98:     x,y;                                    \
+#define EXT(start,end)				\
         .section __ex_table,ALLOC;		\
         .align  4;                              \
-        .word   98b, 96f;                       \
-        .text;                                  \
-        .align  4
-
-#define EXT(start,end,handler)			\
-        .section __ex_table,ALLOC;		\
-        .align  4;                              \
-        .word   start, 0, end, handler;         \
+        .word   start, 0, end, cc_fault;         \
         .text;                                  \
         .align  4
 
@@ -252,21 +229,21 @@ __csum_partial_copy_start:
 cc_end_cruft:
 	be	1f
 	 andcc	%o3, 4, %g0
-	EX(ldd	[%o0 + 0x00], %g2, and %o3, 0xf)
+	EX(ldd	[%o0 + 0x00], %g2)
 	add	%o1, 8, %o1
 	addcc	%g2, %g7, %g7
 	add	%o0, 8, %o0
 	addxcc	%g3, %g7, %g7
-	EX2(st	%g2, [%o1 - 0x08])
+	EX(st	%g2, [%o1 - 0x08])
 	addx	%g0, %g7, %g7
 	andcc	%o3, 4, %g0
-	EX2(st	%g3, [%o1 - 0x04])
+	EX(st	%g3, [%o1 - 0x04])
 1:	be	1f
 	 andcc	%o3, 3, %o3
-	EX(ld	[%o0 + 0x00], %g2, add %o3, 4)
+	EX(ld	[%o0 + 0x00], %g2)
 	add	%o1, 4, %o1
 	addcc	%g2, %g7, %g7
-	EX2(st	%g2, [%o1 - 0x04])
+	EX(st	%g2, [%o1 - 0x04])
 	addx	%g0, %g7, %g7
 	andcc	%o3, 3, %g0
 	add	%o0, 4, %o0
@@ -276,14 +253,14 @@ cc_end_cruft:
 	 subcc	%o3, 2, %o3
 	b	4f
 	 or	%g0, %g0, %o4
-2:	EX(lduh	[%o0 + 0x00], %o4, add %o3, 2)
+2:	EX(lduh	[%o0 + 0x00], %o4)
 	add	%o0, 2, %o0
-	EX2(sth	%o4, [%o1 + 0x00])
+	EX(sth	%o4, [%o1 + 0x00])
 	be	6f
 	 add	%o1, 2, %o1
 	sll	%o4, 16, %o4
-4:	EX(ldub	[%o0 + 0x00], %o5, add %g0, 1)
-	EX2(stb	%o5, [%o1 + 0x00])
+4:	EX(ldub	[%o0 + 0x00], %o5)
+	EX(stb	%o5, [%o1 + 0x00])
 	sll	%o5, 8, %o5
 	or	%o5, %o4, %o4
 6:	addcc	%o4, %g7, %g7
@@ -306,9 +283,9 @@ cc_dword_align:
 	 andcc	%o0, 0x2, %g0
 	be	1f
 	 andcc	%o0, 0x4, %g0
-	EX(lduh	[%o0 + 0x00], %g4, add %g1, 0)
+	EX(lduh	[%o0 + 0x00], %g4)
 	sub	%g1, 2, %g1
-	EX2(sth	%g4, [%o1 + 0x00])
+	EX(sth	%g4, [%o1 + 0x00])
 	add	%o0, 2, %o0
 	sll	%g4, 16, %g4
 	addcc	%g4, %g7, %g7
@@ -322,9 +299,9 @@ cc_dword_align:
 	or	%g3, %g7, %g7
 1:	be	3f
 	 andcc	%g1, 0xffffff80, %g0
-	EX(ld	[%o0 + 0x00], %g4, add %g1, 0)
+	EX(ld	[%o0 + 0x00], %g4)
 	sub	%g1, 4, %g1
-	EX2(st	%g4, [%o1 + 0x00])
+	EX(st	%g4, [%o1 + 0x00])
 	add	%o0, 4, %o0
 	addcc	%g4, %g7, %g7
 	add	%o1, 4, %o1
@@ -354,7 +331,7 @@ __csum_partial_copy_sparc_generic:
 	CSUMCOPY_BIGCHUNK(%o0,%o1,%g7,0x20,%o4,%o5,%g2,%g3,%g4,%g5,%o2,%o3)
 	CSUMCOPY_BIGCHUNK(%o0,%o1,%g7,0x40,%o4,%o5,%g2,%g3,%g4,%g5,%o2,%o3)
 	CSUMCOPY_BIGCHUNK(%o0,%o1,%g7,0x60,%o4,%o5,%g2,%g3,%g4,%g5,%o2,%o3)
-10:	EXT(5b, 10b, 20f)		! note for exception handling
+10:	EXT(5b, 10b)			! note for exception handling
 	sub	%g1, 128, %g1		! detract from length
 	addx	%g0, %g7, %g7		! add in last carry bit
 	andcc	%g1, 0xffffff80, %g0	! more to csum?
@@ -379,7 +356,7 @@ cctbl:	CSUMCOPY_LASTCHUNK(%o0,%o1,%g7,0x68,%g2,%g3,%g4,%g5)
 	CSUMCOPY_LASTCHUNK(%o0,%o1,%g7,0x28,%g2,%g3,%g4,%g5)
 	CSUMCOPY_LASTCHUNK(%o0,%o1,%g7,0x18,%g2,%g3,%g4,%g5)
 	CSUMCOPY_LASTCHUNK(%o0,%o1,%g7,0x08,%g2,%g3,%g4,%g5)
-12:	EXT(cctbl, 12b, 22f)		! note for exception table handling
+12:	EXT(cctbl, 12b)			! note for exception table handling
 	addx	%g0, %g7, %g7
 	andcc	%o3, 0xf, %g0		! check for low bits set
 ccte:	bne	cc_end_cruft		! something left, handle it out of band
@@ -390,7 +367,7 @@ ccdbl:	CSUMCOPY_BIGCHUNK_ALIGNED(%o0,%o1,%g7,0x00,%o4,%o5,%g2,%g3,%g4,%g5,%o2,%o
 	CSUMCOPY_BIGCHUNK_ALIGNED(%o0,%o1,%g7,0x20,%o4,%o5,%g2,%g3,%g4,%g5,%o2,%o3)
 	CSUMCOPY_BIGCHUNK_ALIGNED(%o0,%o1,%g7,0x40,%o4,%o5,%g2,%g3,%g4,%g5,%o2,%o3)
 	CSUMCOPY_BIGCHUNK_ALIGNED(%o0,%o1,%g7,0x60,%o4,%o5,%g2,%g3,%g4,%g5,%o2,%o3)
-11:	EXT(ccdbl, 11b, 21f)		! note for exception table handling
+11:	EXT(ccdbl, 11b)			! note for exception table handling
 	sub	%g1, 128, %g1		! detract from length
 	addx	%g0, %g7, %g7		! add in last carry bit
 	andcc	%g1, 0xffffff80, %g0	! more to csum?
@@ -407,9 +384,9 @@ ccslow:	cmp	%g1, 0
 	be,a	1f
 	 srl	%g1, 1, %g4		
 	sub	%g1, 1, %g1	
-	EX(ldub	[%o0], %g5, add %g1, 1)
+	EX(ldub	[%o0], %g5)
 	add	%o0, 1, %o0	
-	EX2(stb	%g5, [%o1])
+	EX(stb	%g5, [%o1])
 	srl	%g1, 1, %g4
 	add	%o1, 1, %o1
 1:	cmp	%g4, 0		
@@ -418,34 +395,34 @@ ccslow:	cmp	%g1, 0
 	andcc	%o0, 2, %g0	
 	be,a	1f
 	 srl	%g4, 1, %g4
-	EX(lduh	[%o0], %o4, add %g1, 0)
+	EX(lduh	[%o0], %o4)
 	sub	%g1, 2, %g1	
 	srl	%o4, 8, %g2
 	sub	%g4, 1, %g4	
-	EX2(stb	%g2, [%o1])
+	EX(stb	%g2, [%o1])
 	add	%o4, %g5, %g5
-	EX2(stb	%o4, [%o1 + 1])
+	EX(stb	%o4, [%o1 + 1])
 	add	%o0, 2, %o0	
 	srl	%g4, 1, %g4
 	add	%o1, 2, %o1
 1:	cmp	%g4, 0		
 	be,a	2f
 	 andcc	%g1, 2, %g0
-	EX3(ld	[%o0], %o4)
+	EX(ld	[%o0], %o4)
 5:	srl	%o4, 24, %g2
 	srl	%o4, 16, %g3
-	EX2(stb	%g2, [%o1])
+	EX(stb	%g2, [%o1])
 	srl	%o4, 8, %g2
-	EX2(stb	%g3, [%o1 + 1])
+	EX(stb	%g3, [%o1 + 1])
 	add	%o0, 4, %o0
-	EX2(stb	%g2, [%o1 + 2])
+	EX(stb	%g2, [%o1 + 2])
 	addcc	%o4, %g5, %g5
-	EX2(stb	%o4, [%o1 + 3])
+	EX(stb	%o4, [%o1 + 3])
 	addx	%g5, %g0, %g5	! I am now to lazy to optimize this (question it
 	add	%o1, 4, %o1	! is worthy). Maybe some day - with the sll/srl
 	subcc	%g4, 1, %g4	! tricks
 	bne,a	5b
-	 EX3(ld	[%o0], %o4)
+	 EX(ld	[%o0], %o4)
 	sll	%g5, 16, %g2
 	srl	%g5, 16, %g5
 	srl	%g2, 16, %g2
@@ -453,19 +430,19 @@ ccslow:	cmp	%g1, 0
 	add	%g2, %g5, %g5 
 2:	be,a	3f		
 	 andcc	%g1, 1, %g0
-	EX(lduh	[%o0], %o4, and %g1, 3)
+	EX(lduh	[%o0], %o4)
 	andcc	%g1, 1, %g0
 	srl	%o4, 8, %g2
 	add	%o0, 2, %o0	
-	EX2(stb	%g2, [%o1])
+	EX(stb	%g2, [%o1])
 	add	%g5, %o4, %g5
-	EX2(stb	%o4, [%o1 + 1])
+	EX(stb	%o4, [%o1 + 1])
 	add	%o1, 2, %o1
 3:	be,a	1f		
 	 sll	%g5, 16, %o4
-	EX(ldub	[%o0], %g2, add %g0, 1)
+	EX(ldub	[%o0], %g2)
 	sll	%g2, 8, %o4	
-	EX2(stb	%g2, [%o1])
+	EX(stb	%g2, [%o1])
 	add	%g5, %o4, %g5
 	sll	%g5, 16, %o4
 1:	addcc	%o4, %g5, %g5
@@ -481,113 +458,10 @@ ccslow:	cmp	%g1, 0
 4:	addcc	%g7, %g5, %g7
 	retl	
 	 addx	%g0, %g7, %o0
-__csum_partial_copy_end:
 
 /* We do these strange calculations for the csum_*_from_user case only, ie.
  * we only bother with faults on loads... */
 
-/* o2 = ((g2%20)&3)*8
- * o3 = g1 - (g2/20)*32 - o2 */
-20:
-	cmp	%g2, 20
-	blu,a	1f
-	 and	%g2, 3, %o2
-	sub	%g1, 32, %g1
-	b	20b
-	 sub	%g2, 20, %g2
-1:
-	sll	%o2, 3, %o2
-	b	31f
-	 sub	%g1, %o2, %o3
-
-/* o2 = (!(g2 & 15) ? 0 : (((g2 & 15) + 1) & ~1)*8)
- * o3 = g1 - (g2/16)*32 - o2 */
-21:
-	andcc	%g2, 15, %o3
-	srl	%g2, 4, %g2
-	be,a	1f
-	 clr	%o2
-	add	%o3, 1, %o3
-	and	%o3, 14, %o3
-	sll	%o3, 3, %o2
-1:
-	sll	%g2, 5, %g2
-	sub	%g1, %g2, %o3
-	b	31f
-	 sub	%o3, %o2, %o3
-
-/* o0 += (g2/10)*16 - 0x70
- * 01 += (g2/10)*16 - 0x70
- * o2 = (g2 % 10) ? 8 : 0
- * o3 += 0x70 - (g2/10)*16 - o2 */
-22:
-	cmp	%g2, 10
-	blu,a	1f
-	 sub	%o0, 0x70, %o0
-	add	%o0, 16, %o0
-	add	%o1, 16, %o1
-	sub	%o3, 16, %o3
-	b	22b
-	 sub	%g2, 10, %g2
-1:
-	sub	%o1, 0x70, %o1
-	add	%o3, 0x70, %o3
-	clr	%o2
-	tst	%g2
-	bne,a	1f
-	 mov	8, %o2
-1:
-	b	31f
-	 sub	%o3, %o2, %o3
-96:
-	and	%g1, 3, %g1
-	sll	%g4, 2, %g4
-	add	%g1, %g4, %o3
-30:
-/* %o1 is dst
- * %o3 is # bytes to zero out
- * %o4 is faulting address
- * %o5 is %pc where fault occurred */
-	clr	%o2
-31:
-/* %o0 is src
- * %o1 is dst
- * %o2 is # of bytes to copy from src to dst
- * %o3 is # bytes to zero out
- * %o4 is faulting address
- * %o5 is %pc where fault occurred */
-	save	%sp, -104, %sp
-        mov     %i5, %o0
-        mov     %i7, %o1
-        mov	%i4, %o2
-        call    lookup_fault
-	 mov	%g7, %i4
-	cmp	%o0, 2
-	bne	1f	
-	 add	%g0, -EFAULT, %i5
-	tst	%i2
-	be	2f
-	 mov	%i0, %o1
-	mov	%i1, %o0
-5:
-	call	memcpy
-	 mov	%i2, %o2
-	tst	%o0
-	bne,a	2f
-	 add	%i3, %i2, %i3
-	add	%i1, %i2, %i1
-2:
-	mov	%i1, %o0
-6:
-	call	__bzero
-	 mov	%i3, %o1
-1:
-	ld	[%sp + 168], %o2		! struct_ptr of parent
-	st	%i5, [%o2]
+cc_fault:
 	ret
-	 restore
-
-        .section __ex_table,#alloc
-        .align 4
-        .word 5b,2
-	.word 6b,2
+	 clr	%o0
diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c
index 8071bfd72349..40ce087dfecf 100644
--- a/arch/sparc/mm/fault_32.c
+++ b/arch/sparc/mm/fault_32.c
@@ -288,8 +288,6 @@ no_context:
 		if (fixup > 10) {
 			extern const unsigned int __memset_start[];
 			extern const unsigned int __memset_end[];
-			extern const unsigned int __csum_partial_copy_start[];
-			extern const unsigned int __csum_partial_copy_end[];
 
 #ifdef DEBUG_EXCEPTIONS
 			printk("Exception: PC<%08lx> faddr<%08lx>\n",
@@ -298,9 +296,7 @@ no_context:
 				regs->pc, fixup, g2);
 #endif
 			if ((regs->pc >= (unsigned long)__memset_start &&
-			     regs->pc < (unsigned long)__memset_end) ||
-			    (regs->pc >= (unsigned long)__csum_partial_copy_start &&
-			     regs->pc < (unsigned long)__csum_partial_copy_end)) {
+			     regs->pc < (unsigned long)__memset_end)) {
 				regs->u_regs[UREG_I4] = address;
 				regs->u_regs[UREG_I5] = regs->pc;
 			}

From c44ac3c832d49ffd91fb9ec8c172d927b29d8cf7 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 19 Jul 2020 13:59:00 -0400
Subject: [PATCH 13/19] mips: csum_and_copy_{to,from}_user() are never called
 under KERNEL_DS

they are only called for iovec-backed iov_iter and under KERNEL_DS an
attempt to create such a beast will yield a kvec-backed one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/mips/include/asm/checksum.h | 32 +++++++-------------------------
 1 file changed, 7 insertions(+), 25 deletions(-)

diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h
index 9dfce3522760..e3a378495681 100644
--- a/arch/mips/include/asm/checksum.h
+++ b/arch/mips/include/asm/checksum.h
@@ -41,22 +41,6 @@ __wsum __csum_partial_copy_from_user(const void *src, void *dst,
 				     int len, __wsum sum, int *err_ptr);
 __wsum __csum_partial_copy_to_user(const void *src, void *dst,
 				   int len, __wsum sum, int *err_ptr);
-/*
- * this is a new version of the above that records errors it finds in *errp,
- * but continues and zeros the rest of the buffer.
- */
-static inline
-__wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
-				   __wsum sum, int *err_ptr)
-{
-	might_fault();
-	if (uaccess_kernel())
-		return __csum_partial_copy_kernel((__force void *)src, dst,
-						  len, sum, err_ptr);
-	else
-		return __csum_partial_copy_from_user((__force void *)src, dst,
-						     len, sum, err_ptr);
-}
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
@@ -65,9 +49,12 @@ __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
 	__wsum sum = ~0U;
 	int err = 0;
 
+	might_fault();
+
 	if (!access_ok(src, len))
 		return 0;
-	sum = csum_partial_copy_from_user(src, dst, len, sum, &err);
+	sum = __csum_partial_copy_from_user((__force void *)src, dst,
+						     len, sum, &err);
 	return err ? 0 : sum;
 }
 
@@ -84,14 +71,9 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
 	might_fault();
 	if (!access_ok(dst, len))
 		return 0;
-	if (uaccess_kernel())
-		sum = __csum_partial_copy_kernel(src,
-						  (__force void *)dst,
-						  len, sum, &err);
-	else
-		sum = __csum_partial_copy_to_user(src,
-						   (__force void *)dst,
-						   len, sum, &err);
+	sum = __csum_partial_copy_to_user(src,
+					   (__force void *)dst,
+					   len, sum, &err);
 	return err ? 0 : sum;
 }
 

From f863c65c46b479c0bc1b4aa999de1759b1e4036f Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 19 Jul 2020 14:01:58 -0400
Subject: [PATCH 14/19] mips: __csum_partial_copy_kernel() has no users left

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/mips/include/asm/checksum.h | 3 ---
 arch/mips/lib/csum_partial.S     | 3 ---
 2 files changed, 6 deletions(-)

diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h
index e3a378495681..1c41733f6868 100644
--- a/arch/mips/include/asm/checksum.h
+++ b/arch/mips/include/asm/checksum.h
@@ -34,9 +34,6 @@
  */
 __wsum csum_partial(const void *buff, int len, __wsum sum);
 
-__wsum __csum_partial_copy_kernel(const void *src, void *dst,
-				  int len, __wsum sum, int *err_ptr);
-
 __wsum __csum_partial_copy_from_user(const void *src, void *dst,
 				     int len, __wsum sum, int *err_ptr);
 __wsum __csum_partial_copy_to_user(const void *src, void *dst,
diff --git a/arch/mips/lib/csum_partial.S b/arch/mips/lib/csum_partial.S
index 8d70855b0914..983e909c2052 100644
--- a/arch/mips/lib/csum_partial.S
+++ b/arch/mips/lib/csum_partial.S
@@ -827,8 +827,6 @@ EXPORT_SYMBOL(csum_partial)
 	.set	pop
 	.endm
 
-LEAF(__csum_partial_copy_kernel)
-EXPORT_SYMBOL(__csum_partial_copy_kernel)
 #ifndef CONFIG_EVA
 FEXPORT(__csum_partial_copy_to_user)
 EXPORT_SYMBOL(__csum_partial_copy_to_user)
@@ -836,7 +834,6 @@ FEXPORT(__csum_partial_copy_from_user)
 EXPORT_SYMBOL(__csum_partial_copy_from_user)
 #endif
 __BUILD_CSUM_PARTIAL_COPY_USER LEGACY_MODE USEROP USEROP 1
-END(__csum_partial_copy_kernel)
 
 #ifdef CONFIG_EVA
 LEAF(__csum_partial_copy_to_user)

From 1cd95ab85df730b140156baac92fd2640290a5e5 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 19 Jul 2020 17:37:15 -0400
Subject: [PATCH 15/19] mips: propagate the calling convention change down into
 __csum_partial_copy_..._user()

and turn the exception handlers into simply returning 0, which
simplifies the hell out of things in csum_partial.S

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/mips/include/asm/checksum.h |  26 +---
 arch/mips/lib/csum_partial.S     | 260 ++++++++++---------------------
 2 files changed, 90 insertions(+), 196 deletions(-)

diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h
index 1c41733f6868..5f80c28f5253 100644
--- a/arch/mips/include/asm/checksum.h
+++ b/arch/mips/include/asm/checksum.h
@@ -34,25 +34,17 @@
  */
 __wsum csum_partial(const void *buff, int len, __wsum sum);
 
-__wsum __csum_partial_copy_from_user(const void *src, void *dst,
-				     int len, __wsum sum, int *err_ptr);
-__wsum __csum_partial_copy_to_user(const void *src, void *dst,
-				   int len, __wsum sum, int *err_ptr);
+__wsum __csum_partial_copy_from_user(const void __user *src, void *dst, int len);
+__wsum __csum_partial_copy_to_user(const void *src, void __user *dst, int len);
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	__wsum sum = ~0U;
-	int err = 0;
-
 	might_fault();
-
 	if (!access_ok(src, len))
 		return 0;
-	sum = __csum_partial_copy_from_user((__force void *)src, dst,
-						     len, sum, &err);
-	return err ? 0 : sum;
+	return __csum_partial_copy_from_user(src, dst, len);
 }
 
 /*
@@ -62,16 +54,10 @@ __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
 static inline
 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
 {
-	int err = 0;
-	__wsum sum = ~0U;
-
 	might_fault();
 	if (!access_ok(dst, len))
 		return 0;
-	sum = __csum_partial_copy_to_user(src,
-					   (__force void *)dst,
-					   len, sum, &err);
-	return err ? 0 : sum;
+	return __csum_partial_copy_to_user(src, dst, len);
 }
 
 /*
@@ -79,10 +65,10 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
  * we have just one address space, so this is identical to the above)
  */
 #define _HAVE_ARCH_CSUM_AND_COPY
-__wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+__wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len);
 static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return __csum_partial_copy_nocheck(src, dst, len, 0);
+	return __csum_partial_copy_nocheck(src, dst, len);
 }
 
 /*
diff --git a/arch/mips/lib/csum_partial.S b/arch/mips/lib/csum_partial.S
index 983e909c2052..a46db0807195 100644
--- a/arch/mips/lib/csum_partial.S
+++ b/arch/mips/lib/csum_partial.S
@@ -308,8 +308,8 @@ EXPORT_SYMBOL(csum_partial)
 /*
  * checksum and copy routines based on memcpy.S
  *
- *	csum_partial_copy_nocheck(src, dst, len, sum)
- *	__csum_partial_copy_kernel(src, dst, len, sum, errp)
+ *	csum_partial_copy_nocheck(src, dst, len)
+ *	__csum_partial_copy_kernel(src, dst, len)
  *
  * See "Spec" in memcpy.S for details.	Unlike __copy_user, all
  * function in this file use the standard calling convention.
@@ -318,26 +318,11 @@ EXPORT_SYMBOL(csum_partial)
 #define src a0
 #define dst a1
 #define len a2
-#define psum a3
 #define sum v0
 #define odd t8
-#define errptr t9
 
 /*
- * The exception handler for loads requires that:
- *  1- AT contain the address of the byte just past the end of the source
- *     of the copy,
- *  2- src_entry <= src < AT, and
- *  3- (dst - src) == (dst_entry - src_entry),
- * The _entry suffix denotes values when __copy_user was called.
- *
- * (1) is set up up by __csum_partial_copy_from_user and maintained by
- *	not writing AT in __csum_partial_copy
- * (2) is met by incrementing src by the number of bytes copied
- * (3) is met by not doing loads between a pair of increments of dst and src
- *
- * The exception handlers for stores stores -EFAULT to errptr and return.
- * These handlers do not need to overwrite any data.
+ * All exception handlers simply return 0.
  */
 
 /* Instruction type */
@@ -358,11 +343,11 @@ EXPORT_SYMBOL(csum_partial)
  * addr    : Address
  * handler : Exception handler
  */
-#define EXC(insn, type, reg, addr, handler)	\
+#define EXC(insn, type, reg, addr)		\
 	.if \mode == LEGACY_MODE;		\
 9:		insn reg, addr;			\
 		.section __ex_table,"a";	\
-		PTR	9b, handler;		\
+		PTR	9b, .L_exc;		\
 		.previous;			\
 	/* This is enabled in EVA mode */	\
 	.else;					\
@@ -371,7 +356,7 @@ EXPORT_SYMBOL(csum_partial)
 		    ((\to == USEROP) && (type == ST_INSN));	\
 9:			__BUILD_EVA_INSN(insn##e, reg, addr);	\
 			.section __ex_table,"a";		\
-			PTR	9b, handler;			\
+			PTR	9b, .L_exc;			\
 			.previous;				\
 		.else;						\
 			/* EVA without exception */		\
@@ -384,14 +369,14 @@ EXPORT_SYMBOL(csum_partial)
 #ifdef USE_DOUBLE
 
 #define LOADK	ld /* No exception */
-#define LOAD(reg, addr, handler)	EXC(ld, LD_INSN, reg, addr, handler)
-#define LOADBU(reg, addr, handler)	EXC(lbu, LD_INSN, reg, addr, handler)
-#define LOADL(reg, addr, handler)	EXC(ldl, LD_INSN, reg, addr, handler)
-#define LOADR(reg, addr, handler)	EXC(ldr, LD_INSN, reg, addr, handler)
-#define STOREB(reg, addr, handler)	EXC(sb, ST_INSN, reg, addr, handler)
-#define STOREL(reg, addr, handler)	EXC(sdl, ST_INSN, reg, addr, handler)
-#define STORER(reg, addr, handler)	EXC(sdr, ST_INSN, reg, addr, handler)
-#define STORE(reg, addr, handler)	EXC(sd, ST_INSN, reg, addr, handler)
+#define LOAD(reg, addr)		EXC(ld, LD_INSN, reg, addr)
+#define LOADBU(reg, addr)	EXC(lbu, LD_INSN, reg, addr)
+#define LOADL(reg, addr)	EXC(ldl, LD_INSN, reg, addr)
+#define LOADR(reg, addr)	EXC(ldr, LD_INSN, reg, addr)
+#define STOREB(reg, addr)	EXC(sb, ST_INSN, reg, addr)
+#define STOREL(reg, addr)	EXC(sdl, ST_INSN, reg, addr)
+#define STORER(reg, addr)	EXC(sdr, ST_INSN, reg, addr)
+#define STORE(reg, addr)	EXC(sd, ST_INSN, reg, addr)
 #define ADD    daddu
 #define SUB    dsubu
 #define SRL    dsrl
@@ -404,14 +389,14 @@ EXPORT_SYMBOL(csum_partial)
 #else
 
 #define LOADK	lw /* No exception */
-#define LOAD(reg, addr, handler)	EXC(lw, LD_INSN, reg, addr, handler)
-#define LOADBU(reg, addr, handler)	EXC(lbu, LD_INSN, reg, addr, handler)
-#define LOADL(reg, addr, handler)	EXC(lwl, LD_INSN, reg, addr, handler)
-#define LOADR(reg, addr, handler)	EXC(lwr, LD_INSN, reg, addr, handler)
-#define STOREB(reg, addr, handler)	EXC(sb, ST_INSN, reg, addr, handler)
-#define STOREL(reg, addr, handler)	EXC(swl, ST_INSN, reg, addr, handler)
-#define STORER(reg, addr, handler)	EXC(swr, ST_INSN, reg, addr, handler)
-#define STORE(reg, addr, handler)	EXC(sw, ST_INSN, reg, addr, handler)
+#define LOAD(reg, addr)		EXC(lw, LD_INSN, reg, addr)
+#define LOADBU(reg, addr)	EXC(lbu, LD_INSN, reg, addr)
+#define LOADL(reg, addr)	EXC(lwl, LD_INSN, reg, addr)
+#define LOADR(reg, addr)	EXC(lwr, LD_INSN, reg, addr)
+#define STOREB(reg, addr)	EXC(sb, ST_INSN, reg, addr)
+#define STOREL(reg, addr)	EXC(swl, ST_INSN, reg, addr)
+#define STORER(reg, addr)	EXC(swr, ST_INSN, reg, addr)
+#define STORE(reg, addr)	EXC(sw, ST_INSN, reg, addr)
 #define ADD    addu
 #define SUB    subu
 #define SRL    srl
@@ -450,22 +435,9 @@ EXPORT_SYMBOL(csum_partial)
 	.set	at=v1
 #endif
 
-	.macro __BUILD_CSUM_PARTIAL_COPY_USER mode, from, to, __nocheck
+	.macro __BUILD_CSUM_PARTIAL_COPY_USER mode, from, to
 
-	PTR_ADDU	AT, src, len	/* See (1) above. */
-	/* initialize __nocheck if this the first time we execute this
-	 * macro
-	 */
-#ifdef CONFIG_64BIT
-	move	errptr, a4
-#else
-	lw	errptr, 16(sp)
-#endif
-	.if \__nocheck == 1
-	FEXPORT(__csum_partial_copy_nocheck)
-	EXPORT_SYMBOL(__csum_partial_copy_nocheck)
-	.endif
-	move	sum, zero
+	li	sum, -1
 	move	odd, zero
 	/*
 	 * Note: dst & src may be unaligned, len may be 0
@@ -497,31 +469,31 @@ EXPORT_SYMBOL(csum_partial)
 	SUB	len, 8*NBYTES		# subtract here for bgez loop
 	.align	4
 1:
-	LOAD(t0, UNIT(0)(src), .Ll_exc\@)
-	LOAD(t1, UNIT(1)(src), .Ll_exc_copy\@)
-	LOAD(t2, UNIT(2)(src), .Ll_exc_copy\@)
-	LOAD(t3, UNIT(3)(src), .Ll_exc_copy\@)
-	LOAD(t4, UNIT(4)(src), .Ll_exc_copy\@)
-	LOAD(t5, UNIT(5)(src), .Ll_exc_copy\@)
-	LOAD(t6, UNIT(6)(src), .Ll_exc_copy\@)
-	LOAD(t7, UNIT(7)(src), .Ll_exc_copy\@)
+	LOAD(t0, UNIT(0)(src))
+	LOAD(t1, UNIT(1)(src))
+	LOAD(t2, UNIT(2)(src))
+	LOAD(t3, UNIT(3)(src))
+	LOAD(t4, UNIT(4)(src))
+	LOAD(t5, UNIT(5)(src))
+	LOAD(t6, UNIT(6)(src))
+	LOAD(t7, UNIT(7)(src))
 	SUB	len, len, 8*NBYTES
 	ADD	src, src, 8*NBYTES
-	STORE(t0, UNIT(0)(dst),	.Ls_exc\@)
+	STORE(t0, UNIT(0)(dst))
 	ADDC(t0, t1)
-	STORE(t1, UNIT(1)(dst),	.Ls_exc\@)
+	STORE(t1, UNIT(1)(dst))
 	ADDC(sum, t0)
-	STORE(t2, UNIT(2)(dst),	.Ls_exc\@)
+	STORE(t2, UNIT(2)(dst))
 	ADDC(t2, t3)
-	STORE(t3, UNIT(3)(dst),	.Ls_exc\@)
+	STORE(t3, UNIT(3)(dst))
 	ADDC(sum, t2)
-	STORE(t4, UNIT(4)(dst),	.Ls_exc\@)
+	STORE(t4, UNIT(4)(dst))
 	ADDC(t4, t5)
-	STORE(t5, UNIT(5)(dst),	.Ls_exc\@)
+	STORE(t5, UNIT(5)(dst))
 	ADDC(sum, t4)
-	STORE(t6, UNIT(6)(dst),	.Ls_exc\@)
+	STORE(t6, UNIT(6)(dst))
 	ADDC(t6, t7)
-	STORE(t7, UNIT(7)(dst),	.Ls_exc\@)
+	STORE(t7, UNIT(7)(dst))
 	ADDC(sum, t6)
 	.set	reorder				/* DADDI_WAR */
 	ADD	dst, dst, 8*NBYTES
@@ -541,19 +513,19 @@ EXPORT_SYMBOL(csum_partial)
 	/*
 	 * len >= 4*NBYTES
 	 */
-	LOAD(t0, UNIT(0)(src), .Ll_exc\@)
-	LOAD(t1, UNIT(1)(src), .Ll_exc_copy\@)
-	LOAD(t2, UNIT(2)(src), .Ll_exc_copy\@)
-	LOAD(t3, UNIT(3)(src), .Ll_exc_copy\@)
+	LOAD(t0, UNIT(0)(src))
+	LOAD(t1, UNIT(1)(src))
+	LOAD(t2, UNIT(2)(src))
+	LOAD(t3, UNIT(3)(src))
 	SUB	len, len, 4*NBYTES
 	ADD	src, src, 4*NBYTES
-	STORE(t0, UNIT(0)(dst),	.Ls_exc\@)
+	STORE(t0, UNIT(0)(dst))
 	ADDC(t0, t1)
-	STORE(t1, UNIT(1)(dst),	.Ls_exc\@)
+	STORE(t1, UNIT(1)(dst))
 	ADDC(sum, t0)
-	STORE(t2, UNIT(2)(dst),	.Ls_exc\@)
+	STORE(t2, UNIT(2)(dst))
 	ADDC(t2, t3)
-	STORE(t3, UNIT(3)(dst),	.Ls_exc\@)
+	STORE(t3, UNIT(3)(dst))
 	ADDC(sum, t2)
 	.set	reorder				/* DADDI_WAR */
 	ADD	dst, dst, 4*NBYTES
@@ -566,10 +538,10 @@ EXPORT_SYMBOL(csum_partial)
 	beq	rem, len, .Lcopy_bytes\@
 	 nop
 1:
-	LOAD(t0, 0(src), .Ll_exc\@)
+	LOAD(t0, 0(src))
 	ADD	src, src, NBYTES
 	SUB	len, len, NBYTES
-	STORE(t0, 0(dst), .Ls_exc\@)
+	STORE(t0, 0(dst))
 	ADDC(sum, t0)
 	.set	reorder				/* DADDI_WAR */
 	ADD	dst, dst, NBYTES
@@ -592,10 +564,10 @@ EXPORT_SYMBOL(csum_partial)
 	 ADD	t1, dst, len	# t1 is just past last byte of dst
 	li	bits, 8*NBYTES
 	SLL	rem, len, 3	# rem = number of bits to keep
-	LOAD(t0, 0(src), .Ll_exc\@)
+	LOAD(t0, 0(src))
 	SUB	bits, bits, rem # bits = number of bits to discard
 	SHIFT_DISCARD t0, t0, bits
-	STREST(t0, -1(t1), .Ls_exc\@)
+	STREST(t0, -1(t1))
 	SHIFT_DISCARD_REVERT t0, t0, bits
 	.set reorder
 	ADDC(sum, t0)
@@ -612,12 +584,12 @@ EXPORT_SYMBOL(csum_partial)
 	 * Set match = (src and dst have same alignment)
 	 */
 #define match rem
-	LDFIRST(t3, FIRST(0)(src), .Ll_exc\@)
+	LDFIRST(t3, FIRST(0)(src))
 	ADD	t2, zero, NBYTES
-	LDREST(t3, REST(0)(src), .Ll_exc_copy\@)
+	LDREST(t3, REST(0)(src))
 	SUB	t2, t2, t1	# t2 = number of bytes copied
 	xor	match, t0, t1
-	STFIRST(t3, FIRST(0)(dst), .Ls_exc\@)
+	STFIRST(t3, FIRST(0)(dst))
 	SLL	t4, t1, 3		# t4 = number of bits to discard
 	SHIFT_DISCARD t3, t3, t4
 	/* no SHIFT_DISCARD_REVERT to handle odd buffer properly */
@@ -639,26 +611,26 @@ EXPORT_SYMBOL(csum_partial)
  * It's OK to load FIRST(N+1) before REST(N) because the two addresses
  * are to the same unit (unless src is aligned, but it's not).
  */
-	LDFIRST(t0, FIRST(0)(src), .Ll_exc\@)
-	LDFIRST(t1, FIRST(1)(src), .Ll_exc_copy\@)
+	LDFIRST(t0, FIRST(0)(src))
+	LDFIRST(t1, FIRST(1)(src))
 	SUB	len, len, 4*NBYTES
-	LDREST(t0, REST(0)(src), .Ll_exc_copy\@)
-	LDREST(t1, REST(1)(src), .Ll_exc_copy\@)
-	LDFIRST(t2, FIRST(2)(src), .Ll_exc_copy\@)
-	LDFIRST(t3, FIRST(3)(src), .Ll_exc_copy\@)
-	LDREST(t2, REST(2)(src), .Ll_exc_copy\@)
-	LDREST(t3, REST(3)(src), .Ll_exc_copy\@)
+	LDREST(t0, REST(0)(src))
+	LDREST(t1, REST(1)(src))
+	LDFIRST(t2, FIRST(2)(src))
+	LDFIRST(t3, FIRST(3)(src))
+	LDREST(t2, REST(2)(src))
+	LDREST(t3, REST(3)(src))
 	ADD	src, src, 4*NBYTES
 #ifdef CONFIG_CPU_SB1
 	nop				# improves slotting
 #endif
-	STORE(t0, UNIT(0)(dst),	.Ls_exc\@)
+	STORE(t0, UNIT(0)(dst))
 	ADDC(t0, t1)
-	STORE(t1, UNIT(1)(dst),	.Ls_exc\@)
+	STORE(t1, UNIT(1)(dst))
 	ADDC(sum, t0)
-	STORE(t2, UNIT(2)(dst),	.Ls_exc\@)
+	STORE(t2, UNIT(2)(dst))
 	ADDC(t2, t3)
-	STORE(t3, UNIT(3)(dst),	.Ls_exc\@)
+	STORE(t3, UNIT(3)(dst))
 	ADDC(sum, t2)
 	.set	reorder				/* DADDI_WAR */
 	ADD	dst, dst, 4*NBYTES
@@ -671,11 +643,11 @@ EXPORT_SYMBOL(csum_partial)
 	beq	rem, len, .Lcopy_bytes\@
 	 nop
 1:
-	LDFIRST(t0, FIRST(0)(src), .Ll_exc\@)
-	LDREST(t0, REST(0)(src), .Ll_exc_copy\@)
+	LDFIRST(t0, FIRST(0)(src))
+	LDREST(t0, REST(0)(src))
 	ADD	src, src, NBYTES
 	SUB	len, len, NBYTES
-	STORE(t0, 0(dst), .Ls_exc\@)
+	STORE(t0, 0(dst))
 	ADDC(sum, t0)
 	.set	reorder				/* DADDI_WAR */
 	ADD	dst, dst, NBYTES
@@ -696,11 +668,10 @@ EXPORT_SYMBOL(csum_partial)
 #endif
 	move	t2, zero	# partial word
 	li	t3, SHIFT_START # shift
-/* use .Ll_exc_copy here to return correct sum on fault */
 #define COPY_BYTE(N)			\
-	LOADBU(t0, N(src), .Ll_exc_copy\@);	\
+	LOADBU(t0, N(src));		\
 	SUB	len, len, 1;		\
-	STOREB(t0, N(dst), .Ls_exc\@);	\
+	STOREB(t0, N(dst));		\
 	SLLV	t0, t0, t3;		\
 	addu	t3, SHIFT_INC;		\
 	beqz	len, .Lcopy_bytes_done\@; \
@@ -714,9 +685,9 @@ EXPORT_SYMBOL(csum_partial)
 	COPY_BYTE(4)
 	COPY_BYTE(5)
 #endif
-	LOADBU(t0, NBYTES-2(src), .Ll_exc_copy\@)
+	LOADBU(t0, NBYTES-2(src))
 	SUB	len, len, 1
-	STOREB(t0, NBYTES-2(dst), .Ls_exc\@)
+	STOREB(t0, NBYTES-2(dst))
 	SLLV	t0, t0, t3
 	or	t2, t0
 .Lcopy_bytes_done\@:
@@ -753,94 +724,31 @@ EXPORT_SYMBOL(csum_partial)
 #endif
 	.set	pop
 	.set reorder
-	ADDC32(sum, psum)
 	jr	ra
 	.set noreorder
-
-.Ll_exc_copy\@:
-	/*
-	 * Copy bytes from src until faulting load address (or until a
-	 * lb faults)
-	 *
-	 * When reached by a faulting LDFIRST/LDREST, THREAD_BUADDR($28)
-	 * may be more than a byte beyond the last address.
-	 * Hence, the lb below may get an exception.
-	 *
-	 * Assumes src < THREAD_BUADDR($28)
-	 */
-	LOADK	t0, TI_TASK($28)
-	 li	t2, SHIFT_START
-	LOADK	t0, THREAD_BUADDR(t0)
-1:
-	LOADBU(t1, 0(src), .Ll_exc\@)
-	ADD	src, src, 1
-	sb	t1, 0(dst)	# can't fault -- we're copy_from_user
-	SLLV	t1, t1, t2
-	addu	t2, SHIFT_INC
-	ADDC(sum, t1)
-	.set	reorder				/* DADDI_WAR */
-	ADD	dst, dst, 1
-	bne	src, t0, 1b
-	.set	noreorder
-.Ll_exc\@:
-	LOADK	t0, TI_TASK($28)
-	 nop
-	LOADK	t0, THREAD_BUADDR(t0)	# t0 is just past last good address
-	 nop
-	SUB	len, AT, t0		# len number of uncopied bytes
-	/*
-	 * Here's where we rely on src and dst being incremented in tandem,
-	 *   See (3) above.
-	 * dst += (fault addr - src) to put dst at first byte to clear
-	 */
-	ADD	dst, t0			# compute start address in a1
-	SUB	dst, src
-	/*
-	 * Clear len bytes starting at dst.  Can't call __bzero because it
-	 * might modify len.  An inefficient loop for these rare times...
-	 */
-	.set	reorder				/* DADDI_WAR */
-	SUB	src, len, 1
-	beqz	len, .Ldone\@
-	.set	noreorder
-1:	sb	zero, 0(dst)
-	ADD	dst, dst, 1
-	.set	push
-	.set	noat
-#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
-	bnez	src, 1b
-	 SUB	src, src, 1
-#else
-	li	v1, 1
-	bnez	src, 1b
-	 SUB	src, src, v1
-#endif
-	li	v1, -EFAULT
-	b	.Ldone\@
-	 sw	v1, (errptr)
-
-.Ls_exc\@:
-	li	v0, -1 /* invalid checksum */
-	li	v1, -EFAULT
-	jr	ra
-	 sw	v1, (errptr)
-	.set	pop
 	.endm
 
+	.set noreorder
+.L_exc:
+	jr	ra
+	 li	v0, 0
+
+FEXPORT(__csum_partial_copy_nocheck)
+EXPORT_SYMBOL(__csum_partial_copy_nocheck)
 #ifndef CONFIG_EVA
 FEXPORT(__csum_partial_copy_to_user)
 EXPORT_SYMBOL(__csum_partial_copy_to_user)
 FEXPORT(__csum_partial_copy_from_user)
 EXPORT_SYMBOL(__csum_partial_copy_from_user)
 #endif
-__BUILD_CSUM_PARTIAL_COPY_USER LEGACY_MODE USEROP USEROP 1
+__BUILD_CSUM_PARTIAL_COPY_USER LEGACY_MODE USEROP USEROP
 
 #ifdef CONFIG_EVA
 LEAF(__csum_partial_copy_to_user)
-__BUILD_CSUM_PARTIAL_COPY_USER EVA_MODE KERNELOP USEROP 0
+__BUILD_CSUM_PARTIAL_COPY_USER EVA_MODE KERNELOP USEROP
 END(__csum_partial_copy_to_user)
 
 LEAF(__csum_partial_copy_from_user)
-__BUILD_CSUM_PARTIAL_COPY_USER EVA_MODE USEROP KERNELOP 0
+__BUILD_CSUM_PARTIAL_COPY_USER EVA_MODE USEROP KERNELOP
 END(__csum_partial_copy_from_user)
 #endif

From 2a5d2bd159f33ef34484ee14705dcf8634061f2c Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 19 Jul 2020 18:03:51 -0400
Subject: [PATCH 16/19] xtensa: propagate the calling conventions change down
 into csum_partial_copy_generic()

turn the exception handlers into returning 0.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/xtensa/include/asm/checksum.h | 20 ++-------
 arch/xtensa/lib/checksum.S         | 67 +++++++-----------------------
 2 files changed, 19 insertions(+), 68 deletions(-)

diff --git a/arch/xtensa/include/asm/checksum.h b/arch/xtensa/include/asm/checksum.h
index fe78fba7bd64..44ec1d0b2a35 100644
--- a/arch/xtensa/include/asm/checksum.h
+++ b/arch/xtensa/include/asm/checksum.h
@@ -37,9 +37,7 @@ asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
  * better 64-bit) boundary
  */
 
-asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
-					    int len, __wsum sum,
-					    int *src_err_ptr, int *dst_err_ptr);
+asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
 
 #define _HAVE_ARCH_CSUM_AND_COPY
 /*
@@ -49,7 +47,7 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
 static inline
 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
+	return csum_partial_copy_generic(src, dst, len);
 }
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
@@ -57,14 +55,9 @@ static inline
 __wsum csum_and_copy_from_user(const void __user *src, void *dst,
 				   int len)
 {
-	int err = 0;
-
 	if (!access_ok(src, len))
 		return 0;
-
-	sum = csum_partial_copy_generic((__force const void *)src, dst,
-					len, ~0U, &err, NULL);
-	return err ? 0 : sum;
+	return csum_partial_copy_generic((__force const void *)src, dst, len);
 }
 
 /*
@@ -247,13 +240,8 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 static __inline__ __wsum csum_and_copy_to_user(const void *src,
 					       void __user *dst, int len)
 {
-	int err = 0;
-	__wsum sum = ~0U;
-
 	if (!access_ok(dst, len))
 		return 0;
-
-	sum = csum_partial_copy_generic(src,dst,len,sum,NULL,&err);
-	return err ? 0 : sum;
+	return csum_partial_copy_generic(src, (__force void *)dst, len);
 }
 #endif
diff --git a/arch/xtensa/lib/checksum.S b/arch/xtensa/lib/checksum.S
index 4cb9ca58d9ad..cf1bed1a5bd6 100644
--- a/arch/xtensa/lib/checksum.S
+++ b/arch/xtensa/lib/checksum.S
@@ -175,19 +175,14 @@ ENDPROC(csum_partial)
  */
 
 /*
-unsigned int csum_partial_copy_generic (const char *src, char *dst, int len,
-					int sum, int *src_err_ptr, int *dst_err_ptr)
+unsigned int csum_partial_copy_generic (const char *src, char *dst, int len)
 	a2  = src
 	a3  = dst
 	a4  = len
 	a5  = sum
-	a6  = src_err_ptr
-	a7  = dst_err_ptr
 	a8  = temp
 	a9  = temp
 	a10 = temp
-	a11 = original len for exception handling
-	a12 = original dst for exception handling
 
     This function is optimized for 4-byte aligned addresses.  Other
     alignments work, but not nearly as efficiently.
@@ -196,8 +191,7 @@ unsigned int csum_partial_copy_generic (const char *src, char *dst, int len,
 ENTRY(csum_partial_copy_generic)
 
 	abi_entry_default
-	mov	a12, a3
-	mov	a11, a4
+	movi	a5, -1
 	or	a10, a2, a3
 
 	/* We optimize the following alignment tests for the 4-byte
@@ -228,26 +222,26 @@ ENTRY(csum_partial_copy_generic)
 #endif
 EX(10f)	l32i	a9, a2, 0
 EX(10f)	l32i	a8, a2, 4
-EX(11f)	s32i	a9, a3, 0
-EX(11f)	s32i	a8, a3, 4
+EX(10f)	s32i	a9, a3, 0
+EX(10f)	s32i	a8, a3, 4
 	ONES_ADD(a5, a9)
 	ONES_ADD(a5, a8)
 EX(10f)	l32i	a9, a2, 8
 EX(10f)	l32i	a8, a2, 12
-EX(11f)	s32i	a9, a3, 8
-EX(11f)	s32i	a8, a3, 12
+EX(10f)	s32i	a9, a3, 8
+EX(10f)	s32i	a8, a3, 12
 	ONES_ADD(a5, a9)
 	ONES_ADD(a5, a8)
 EX(10f)	l32i	a9, a2, 16
 EX(10f)	l32i	a8, a2, 20
-EX(11f)	s32i	a9, a3, 16
-EX(11f)	s32i	a8, a3, 20
+EX(10f)	s32i	a9, a3, 16
+EX(10f)	s32i	a8, a3, 20
 	ONES_ADD(a5, a9)
 	ONES_ADD(a5, a8)
 EX(10f)	l32i	a9, a2, 24
 EX(10f)	l32i	a8, a2, 28
-EX(11f)	s32i	a9, a3, 24
-EX(11f)	s32i	a8, a3, 28
+EX(10f)	s32i	a9, a3, 24
+EX(10f)	s32i	a8, a3, 28
 	ONES_ADD(a5, a9)
 	ONES_ADD(a5, a8)
 	addi	a2, a2, 32
@@ -267,7 +261,7 @@ EX(11f)	s32i	a8, a3, 28
 .Loop6:
 #endif
 EX(10f)	l32i	a9, a2, 0
-EX(11f)	s32i	a9, a3, 0
+EX(10f)	s32i	a9, a3, 0
 	ONES_ADD(a5, a9)
 	addi	a2, a2, 4
 	addi	a3, a3, 4
@@ -298,7 +292,7 @@ EX(11f)	s32i	a9, a3, 0
 .Loop7:
 #endif
 EX(10f)	l16ui	a9, a2, 0
-EX(11f)	s16i	a9, a3, 0
+EX(10f)	s16i	a9, a3, 0
 	ONES_ADD(a5, a9)
 	addi	a2, a2, 2
 	addi	a3, a3, 2
@@ -309,7 +303,7 @@ EX(11f)	s16i	a9, a3, 0
 	/* This section processes a possible trailing odd byte. */
 	_bbci.l	a4, 0, 8f	/* 1-byte chunk */
 EX(10f)	l8ui	a9, a2, 0
-EX(11f)	s8i	a9, a3, 0
+EX(10f)	s8i	a9, a3, 0
 #ifdef __XTENSA_EB__
 	slli	a9, a9, 8	/* shift byte to bits 8..15 */
 #endif
@@ -334,8 +328,8 @@ EX(11f)	s8i	a9, a3, 0
 #endif
 EX(10f)	l8ui	a9, a2, 0
 EX(10f)	l8ui	a8, a2, 1
-EX(11f)	s8i	a9, a3, 0
-EX(11f)	s8i	a8, a3, 1
+EX(10f)	s8i	a9, a3, 0
+EX(10f)	s8i	a8, a3, 1
 #ifdef __XTENSA_EB__
 	slli	a9, a9, 8	/* combine into a single 16-bit value */
 #else				/* for checksum computation */
@@ -356,38 +350,7 @@ ENDPROC(csum_partial_copy_generic)
 
 # Exception handler:
 .section .fixup, "ax"
-/*
-	a6  = src_err_ptr
-	a7  = dst_err_ptr
-	a11 = original len for exception handling
-	a12 = original dst for exception handling
-*/
-
 10:
-	_movi	a2, -EFAULT
-	s32i	a2, a6, 0	/* src_err_ptr */
-
-	# clear the complete destination - computing the rest
-	# is too much work
-	movi	a2, 0
-#if XCHAL_HAVE_LOOPS
-	loopgtz	a11, 2f
-#else
-	beqz	a11, 2f
-	add	a11, a11, a12	/* a11 = ending address */
-.Leloop:
-#endif
-	s8i	a2, a12, 0
-	addi	a12, a12, 1
-#if !XCHAL_HAVE_LOOPS
-	blt	a12, a11, .Leloop
-#endif
-2:
-	abi_ret_default
-
-11:
-	movi	a2, -EFAULT
-	s32i	a2, a7, 0	/* dst_err_ptr */
 	movi	a2, 0
 	abi_ret_default
 

From fdf8bee96f9aeaac4559725c2dfae6e1bd7b7043 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 19 Jul 2020 18:31:07 -0400
Subject: [PATCH 17/19] sparc64: propagate the calling convention changes down
 to __csum_partial_copy_...()

... and rename them into csum_and_copy_...() - the wrappers become pointless.
[braino fixed]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/sparc/include/asm/checksum.h    |  1 +
 arch/sparc/include/asm/checksum_32.h |  2 --
 arch/sparc/include/asm/checksum_64.h | 41 ++--------------------------
 arch/sparc/lib/csum_copy.S           |  5 ++--
 arch/sparc/lib/csum_copy_from_user.S |  4 +--
 arch/sparc/lib/csum_copy_to_user.S   |  4 +--
 6 files changed, 11 insertions(+), 46 deletions(-)

diff --git a/arch/sparc/include/asm/checksum.h b/arch/sparc/include/asm/checksum.h
index deb4fe5aeafd..f2ac13323b6d 100644
--- a/arch/sparc/include/asm/checksum.h
+++ b/arch/sparc/include/asm/checksum.h
@@ -3,6 +3,7 @@
 #define ___ASM_SPARC_CHECKSUM_H
 #define _HAVE_ARCH_CSUM_AND_COPY
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+#define HAVE_CSUM_COPY_USER
 #if defined(__sparc__) && defined(__arch64__)
 #include <asm/checksum_64.h>
 #else
diff --git a/arch/sparc/include/asm/checksum_32.h b/arch/sparc/include/asm/checksum_32.h
index d55e480172a6..ce11e0ad80c7 100644
--- a/arch/sparc/include/asm/checksum_32.h
+++ b/arch/sparc/include/asm/checksum_32.h
@@ -67,8 +67,6 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len)
 	return csum_partial_copy_nocheck((__force void *)src, dst, len);
 }
 
-#define HAVE_CSUM_COPY_USER
-
 static inline __wsum
 csum_and_copy_to_user(const void *src, void __user *dst, int len)
 {
diff --git a/arch/sparc/include/asm/checksum_64.h b/arch/sparc/include/asm/checksum_64.h
index 4d0bbff43e62..d6b59461e064 100644
--- a/arch/sparc/include/asm/checksum_64.h
+++ b/arch/sparc/include/asm/checksum_64.h
@@ -38,44 +38,9 @@ __wsum csum_partial(const void * buff, int len, __wsum sum);
  * here even more important to align src and dst on a 32-bit (or even
  * better 64-bit) boundary
  */
-__wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
-
-static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
-{
-	return __csum_partial_copy_nocheck(src, dst, len, 0);
-}
-
-long __csum_partial_copy_from_user(const void __user *src,
-				   void *dst, int len,
-				   __wsum sum);
-
-static inline __wsum
-csum_and_copy_from_user(const void __user *src,
-			    void *dst, int len)
-{
-	long ret = __csum_partial_copy_from_user(src, dst, len, ~0U);
-	if (ret < 0)
-		return 0;
-	return (__force __wsum) ret;
-}
-
-/*
- *	Copy and checksum to user
- */
-#define HAVE_CSUM_COPY_USER
-long __csum_partial_copy_to_user(const void *src,
-				 void __user *dst, int len,
-				 __wsum sum);
-
-static inline __wsum
-csum_and_copy_to_user(const void *src,
-		      void __user *dst, int len)
-{
-	long ret = __csum_partial_copy_to_user(src, dst, len, ~0U);
-	if (ret < 0)
-		return 0;
-	return (__force __wsum) ret;
-}
+__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);
+__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len);
+__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len);
 
 /* ihl is always 5 or greater, almost always is 5, and iph is word aligned
  * the majority of the time.
diff --git a/arch/sparc/lib/csum_copy.S b/arch/sparc/lib/csum_copy.S
index 72c900d21b12..0c0268e77155 100644
--- a/arch/sparc/lib/csum_copy.S
+++ b/arch/sparc/lib/csum_copy.S
@@ -33,7 +33,7 @@
 #endif
 
 #ifndef FUNC_NAME
-#define FUNC_NAME	__csum_partial_copy_nocheck
+#define FUNC_NAME	csum_partial_copy_nocheck
 #endif
 
 	.register	%g2, #scratch
@@ -68,9 +68,10 @@
 	.globl		FUNC_NAME
 	.type		FUNC_NAME,#function
 	EXPORT_SYMBOL(FUNC_NAME)
-FUNC_NAME:		/* %o0=src, %o1=dst, %o2=len, %o3=sum */
+FUNC_NAME:		/* %o0=src, %o1=dst, %o2=len */
 	LOAD(prefetch, %o0 + 0x000, #n_reads)
 	xor		%o0, %o1, %g1
+	mov		1, %o3
 	clr		%o4
 	andcc		%g1, 0x3, %g0
 	bne,pn		%icc, 95f
diff --git a/arch/sparc/lib/csum_copy_from_user.S b/arch/sparc/lib/csum_copy_from_user.S
index d20b9594f0c7..b0ba8d4dd439 100644
--- a/arch/sparc/lib/csum_copy_from_user.S
+++ b/arch/sparc/lib/csum_copy_from_user.S
@@ -9,14 +9,14 @@
 	.section .fixup, "ax";	\
 	.align 4;		\
 99:	retl;			\
-	 mov	-1, %o0;	\
+	 mov	0, %o0;		\
 	.section __ex_table,"a";\
 	.align 4;		\
 	.word 98b, 99b;		\
 	.text;			\
 	.align 4;
 
-#define FUNC_NAME		__csum_partial_copy_from_user
+#define FUNC_NAME		csum_and_copy_from_user
 #define LOAD(type,addr,dest)	type##a [addr] %asi, dest
 
 #include "csum_copy.S"
diff --git a/arch/sparc/lib/csum_copy_to_user.S b/arch/sparc/lib/csum_copy_to_user.S
index d71c0c81e8ab..91ba36dbf7d2 100644
--- a/arch/sparc/lib/csum_copy_to_user.S
+++ b/arch/sparc/lib/csum_copy_to_user.S
@@ -9,14 +9,14 @@
 	.section .fixup,"ax";	\
 	.align 4;		\
 99:	retl;			\
-	 mov	-1, %o0;	\
+	 mov	0, %o0;		\
 	.section __ex_table,"a";\
 	.align 4;		\
 	.word 98b, 99b;		\
 	.text;			\
 	.align 4;
 
-#define FUNC_NAME		__csum_partial_copy_to_user
+#define FUNC_NAME		csum_and_copy_to_user
 #define STORE(type,src,addr)	type##a src, [addr] %asi
 
 #include "csum_copy.S"

From daf52375c19feb4397cfd883302a7c907de2d6ad Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 19 Jul 2020 21:56:07 -0400
Subject: [PATCH 18/19] amd64: switch csum_partial_copy_generic() to new
 calling conventions

... and fold handling of misaligned case into it.

Implementation note: we stash the "will we need to rol8 the sum in the end"
flag into the MSB of %rcx (the lower 32 bits are used for length); the rest
is pretty straightforward.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/x86/include/asm/checksum_64.h |   5 +-
 arch/x86/lib/csum-copy_64.S        | 140 +++++++++++++++++------------
 arch/x86/lib/csum-wrappers_64.c    |  72 ++-------------
 3 files changed, 94 insertions(+), 123 deletions(-)

diff --git a/arch/x86/include/asm/checksum_64.h b/arch/x86/include/asm/checksum_64.h
index 9af3aed54c6b..407beebadaf4 100644
--- a/arch/x86/include/asm/checksum_64.h
+++ b/arch/x86/include/asm/checksum_64.h
@@ -130,10 +130,7 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
 /* Do not call this directly. Use the wrappers below */
-extern __visible __wsum csum_partial_copy_generic(const void *src, const void *dst,
-					int len, __wsum sum,
-					int *src_err_ptr, int *dst_err_ptr);
-
+extern __visible __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
 
 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len);
 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len);
diff --git a/arch/x86/lib/csum-copy_64.S b/arch/x86/lib/csum-copy_64.S
index 3394a8ff7fd0..1fbd8ee9642d 100644
--- a/arch/x86/lib/csum-copy_64.S
+++ b/arch/x86/lib/csum-copy_64.S
@@ -18,9 +18,6 @@
  * rdi  source
  * rsi  destination
  * edx  len (32bit)
- * ecx  sum (32bit)
- * r8   src_err_ptr (int)
- * r9   dst_err_ptr (int)
  *
  * Output
  * eax  64bit sum. undefined in case of exception.
@@ -31,44 +28,32 @@
 
 	.macro source
 10:
-	_ASM_EXTABLE_UA(10b, .Lbad_source)
+	_ASM_EXTABLE_UA(10b, .Lfault)
 	.endm
 
 	.macro dest
 20:
-	_ASM_EXTABLE_UA(20b, .Lbad_dest)
+	_ASM_EXTABLE_UA(20b, .Lfault)
 	.endm
 
-	/*
-	 * No _ASM_EXTABLE_UA; this is used for intentional prefetch on a
-	 * potentially unmapped kernel address.
-	 */
-	.macro ignore L=.Lignore
-30:
-	_ASM_EXTABLE(30b, \L)
-	.endm
-
-
 SYM_FUNC_START(csum_partial_copy_generic)
-	cmpl	$3*64, %edx
-	jle	.Lignore
-
-.Lignore:
-	subq  $7*8, %rsp
-	movq  %rbx, 2*8(%rsp)
-	movq  %r12, 3*8(%rsp)
-	movq  %r14, 4*8(%rsp)
-	movq  %r13, 5*8(%rsp)
-	movq  %r15, 6*8(%rsp)
-
-	movq  %r8, (%rsp)
-	movq  %r9, 1*8(%rsp)
-
-	movl  %ecx, %eax
-	movl  %edx, %ecx
+	subq  $5*8, %rsp
+	movq  %rbx, 0*8(%rsp)
+	movq  %r12, 1*8(%rsp)
+	movq  %r14, 2*8(%rsp)
+	movq  %r13, 3*8(%rsp)
+	movq  %r15, 4*8(%rsp)
 
+	movl  $-1, %eax
 	xorl  %r9d, %r9d
-	movq  %rcx, %r12
+	movl  %edx, %ecx
+	cmpl  $8, %ecx
+	jb    .Lshort
+
+	testb  $7, %sil
+	jne   .Lunaligned
+.Laligned:
+	movl  %ecx, %r12d
 
 	shrq  $6, %r12
 	jz	.Lhandle_tail       /* < 64 */
@@ -99,7 +84,12 @@ SYM_FUNC_START(csum_partial_copy_generic)
 	source
 	movq  56(%rdi), %r13
 
-	ignore 2f
+30:
+	/*
+	 * No _ASM_EXTABLE_UA; this is used for intentional prefetch on a
+	 * potentially unmapped kernel address.
+	 */
+	_ASM_EXTABLE(30b, 2f)
 	prefetcht0 5*64(%rdi)
 2:
 	adcq  %rbx, %rax
@@ -131,8 +121,6 @@ SYM_FUNC_START(csum_partial_copy_generic)
 	dest
 	movq %r13, 56(%rsi)
 
-3:
-
 	leaq 64(%rdi), %rdi
 	leaq 64(%rsi), %rsi
 
@@ -142,8 +130,8 @@ SYM_FUNC_START(csum_partial_copy_generic)
 
 	/* do last up to 56 bytes */
 .Lhandle_tail:
-	/* ecx:	count */
-	movl %ecx, %r10d
+	/* ecx:	count, rcx.63: the end result needs to be rol8 */
+	movq %rcx, %r10
 	andl $63, %ecx
 	shrl $3, %ecx
 	jz	.Lfold
@@ -172,6 +160,7 @@ SYM_FUNC_START(csum_partial_copy_generic)
 .Lhandle_7:
 	movl %r10d, %ecx
 	andl $7, %ecx
+.L1:				/* .Lshort rejoins the common path here */
 	shrl $1, %ecx
 	jz   .Lhandle_1
 	movl $2, %edx
@@ -203,26 +192,65 @@ SYM_FUNC_START(csum_partial_copy_generic)
 	adcl %r9d, %eax		/* carry */
 
 .Lende:
-	movq 2*8(%rsp), %rbx
-	movq 3*8(%rsp), %r12
-	movq 4*8(%rsp), %r14
-	movq 5*8(%rsp), %r13
-	movq 6*8(%rsp), %r15
-	addq $7*8, %rsp
+	testq %r10, %r10
+	js  .Lwas_odd
+.Lout:
+	movq 0*8(%rsp), %rbx
+	movq 1*8(%rsp), %r12
+	movq 2*8(%rsp), %r14
+	movq 3*8(%rsp), %r13
+	movq 4*8(%rsp), %r15
+	addq $5*8, %rsp
 	ret
+.Lshort:
+	movl %ecx, %r10d
+	jmp  .L1
+.Lunaligned:
+	xorl %ebx, %ebx
+	testb $1, %sil
+	jne  .Lodd
+1:	testb $2, %sil
+	je   2f
+	source
+	movw (%rdi), %bx
+	dest
+	movw %bx, (%rsi)
+	leaq 2(%rdi), %rdi
+	subq $2, %rcx
+	leaq 2(%rsi), %rsi
+	addq %rbx, %rax
+2:	testb $4, %sil
+	je .Laligned
+	source
+	movl (%rdi), %ebx
+	dest
+	movl %ebx, (%rsi)
+	leaq 4(%rdi), %rdi
+	subq $4, %rcx
+	leaq 4(%rsi), %rsi
+	addq %rbx, %rax
+	jmp .Laligned
 
-	/* Exception handlers. Very simple, zeroing is done in the wrappers */
-.Lbad_source:
-	movq (%rsp), %rax
-	testq %rax, %rax
-	jz   .Lende
-	movl $-EFAULT, (%rax)
-	jmp  .Lende
+.Lodd:
+	source
+	movb (%rdi), %bl
+	dest
+	movb %bl, (%rsi)
+	leaq 1(%rdi), %rdi
+	leaq 1(%rsi), %rsi
+	/* decrement, set MSB */
+	leaq -1(%rcx, %rcx), %rcx
+	rorq $1, %rcx
+	shll $8, %ebx
+	addq %rbx, %rax
+	jmp 1b
 
-.Lbad_dest:
-	movq 8(%rsp), %rax
-	testq %rax, %rax
-	jz   .Lende
-	movl $-EFAULT, (%rax)
-	jmp .Lende
+.Lwas_odd:
+	roll $8, %eax
+	jmp .Lout
+
+	/* Exception: just return 0 */
+.Lfault:
+	xorl %eax, %eax
+	jmp  .Lout
 SYM_FUNC_END(csum_partial_copy_generic)
diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c
index ae2fb87e2274..189344924a2b 100644
--- a/arch/x86/lib/csum-wrappers_64.c
+++ b/arch/x86/lib/csum-wrappers_64.c
@@ -21,49 +21,16 @@
  * src and dst are best aligned to 64bits.
  */
 __wsum
-csum_and_copy_from_user(const void __user *src, void *dst,
-			    int len)
+csum_and_copy_from_user(const void __user *src, void *dst, int len)
 {
-	int err = 0;
-	__wsum isum = ~0U;
+	__wsum sum;
 
 	might_sleep();
-
 	if (!user_access_begin(src, len))
 		return 0;
-
-	/*
-	 * Why 6, not 7? To handle odd addresses aligned we
-	 * would need to do considerable complications to fix the
-	 * checksum which is defined as an 16bit accumulator. The
-	 * fix alignment code is primarily for performance
-	 * compatibility with 32bit and that will handle odd
-	 * addresses slowly too.
-	 */
-	if (unlikely((unsigned long)src & 6)) {
-		while (((unsigned long)src & 6) && len >= 2) {
-			__u16 val16;
-
-			unsafe_get_user(val16, (const __u16 __user *)src, out);
-
-			*(__u16 *)dst = val16;
-			isum = (__force __wsum)add32_with_carry(
-					(__force unsigned)isum, val16);
-			src += 2;
-			dst += 2;
-			len -= 2;
-		}
-	}
-	isum = csum_partial_copy_generic((__force const void *)src,
-				dst, len, isum, &err, NULL);
+	sum = csum_partial_copy_generic((__force const void *)src, dst, len);
 	user_access_end();
-	if (unlikely(err))
-		isum = 0;
-	return isum;
-
-out:
-	user_access_end();
-	return 0;
+	return sum;
 }
 EXPORT_SYMBOL(csum_and_copy_from_user);
 
@@ -79,37 +46,16 @@ EXPORT_SYMBOL(csum_and_copy_from_user);
  * src and dst are best aligned to 64bits.
  */
 __wsum
-csum_and_copy_to_user(const void *src, void __user *dst,
-			  int len)
+csum_and_copy_to_user(const void *src, void __user *dst, int len)
 {
-	__wsum ret, isum = ~0U;
-	int err = 0;
+	__wsum sum;
 
 	might_sleep();
-
 	if (!user_access_begin(dst, len))
 		return 0;
-
-	if (unlikely((unsigned long)dst & 6)) {
-		while (((unsigned long)dst & 6) && len >= 2) {
-			__u16 val16 = *(__u16 *)src;
-
-			isum = (__force __wsum)add32_with_carry(
-					(__force unsigned)isum, val16);
-			unsafe_put_user(val16, (__u16 __user *)dst, out);
-			src += 2;
-			dst += 2;
-			len -= 2;
-		}
-	}
-
-	ret = csum_partial_copy_generic(src, (void __force *)dst,
-					len, isum, NULL, &err);
+	sum = csum_partial_copy_generic(src, (void __force *)dst, len);
 	user_access_end();
-	return err ? 0 : ret;
-out:
-	user_access_end();
-	return 0;
+	return sum;
 }
 EXPORT_SYMBOL(csum_and_copy_to_user);
 
@@ -125,7 +71,7 @@ EXPORT_SYMBOL(csum_and_copy_to_user);
 __wsum
 csum_partial_copy_nocheck(const void *src, void *dst, int len)
 {
-	return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
+	return csum_partial_copy_generic(src, dst, len);
 }
 EXPORT_SYMBOL(csum_partial_copy_nocheck);
 

From 70d65cd555c5e43c613700f604a47f7ebcf7b6f1 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 20 Jul 2020 10:09:24 -0400
Subject: [PATCH 19/19] ppc: propagate the calling conventions change down to
 csum_partial_copy_generic()

... and get rid of the pointless fallback in the wrappers.  On error it used
to zero the unwritten area and calculate the csum of the entire thing.  Not
wanting to do it in assembler part had been very reasonable; doing that in
the first place, OTOH...  In case of an error the caller discards the data
we'd copied, along with whatever checksum it might've had.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/powerpc/include/asm/checksum.h  |  6 +--
 arch/powerpc/lib/checksum_32.S       | 74 ++++++++++------------------
 arch/powerpc/lib/checksum_64.S       | 37 +++++---------
 arch/powerpc/lib/checksum_wrappers.c | 32 +++---------
 4 files changed, 46 insertions(+), 103 deletions(-)

diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index dba685d984c0..82f099ba2411 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -18,9 +18,7 @@
  * Like csum_partial, this must be called with even lengths,
  * except for the last fragment.
  */
-extern __wsum csum_partial_copy_generic(const void *src, void *dst,
-					      int len, __wsum sum,
-					      int *src_err, int *dst_err);
+extern __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
 
 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
@@ -31,7 +29,7 @@ extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
 
 #define _HAVE_ARCH_CSUM_AND_COPY
 #define csum_partial_copy_nocheck(src, dst, len)   \
-        csum_partial_copy_generic((src), (dst), (len), 0, NULL, NULL)
+        csum_partial_copy_generic((src), (dst), (len))
 
 
 /*
diff --git a/arch/powerpc/lib/checksum_32.S b/arch/powerpc/lib/checksum_32.S
index ecd150dc3ed9..ec5cd2dede35 100644
--- a/arch/powerpc/lib/checksum_32.S
+++ b/arch/powerpc/lib/checksum_32.S
@@ -78,12 +78,10 @@ EXPORT_SYMBOL(__csum_partial)
 
 /*
  * Computes the checksum of a memory block at src, length len,
- * and adds in "sum" (32-bit), while copying the block to dst.
- * If an access exception occurs on src or dst, it stores -EFAULT
- * to *src_err or *dst_err respectively, and (for an error on
- * src) zeroes the rest of dst.
+ * and adds in 0xffffffff, while copying the block to dst.
+ * If an access exception occurs it returns zero.
  *
- * csum_partial_copy_generic(src, dst, len, sum, src_err, dst_err)
+ * csum_partial_copy_generic(src, dst, len)
  */
 #define CSUM_COPY_16_BYTES_WITHEX(n)	\
 8 ## n ## 0:			\
@@ -108,14 +106,14 @@ EXPORT_SYMBOL(__csum_partial)
 	adde	r12,r12,r10
 
 #define CSUM_COPY_16_BYTES_EXCODE(n)		\
-	EX_TABLE(8 ## n ## 0b, src_error);	\
-	EX_TABLE(8 ## n ## 1b, src_error);	\
-	EX_TABLE(8 ## n ## 2b, src_error);	\
-	EX_TABLE(8 ## n ## 3b, src_error);	\
-	EX_TABLE(8 ## n ## 4b, dst_error);	\
-	EX_TABLE(8 ## n ## 5b, dst_error);	\
-	EX_TABLE(8 ## n ## 6b, dst_error);	\
-	EX_TABLE(8 ## n ## 7b, dst_error);
+	EX_TABLE(8 ## n ## 0b, fault);	\
+	EX_TABLE(8 ## n ## 1b, fault);	\
+	EX_TABLE(8 ## n ## 2b, fault);	\
+	EX_TABLE(8 ## n ## 3b, fault);	\
+	EX_TABLE(8 ## n ## 4b, fault);	\
+	EX_TABLE(8 ## n ## 5b, fault);	\
+	EX_TABLE(8 ## n ## 6b, fault);	\
+	EX_TABLE(8 ## n ## 7b, fault);
 
 	.text
 	.stabs	"arch/powerpc/lib/",N_SO,0,0,0f
@@ -127,11 +125,8 @@ LG_CACHELINE_BYTES = L1_CACHE_SHIFT
 CACHELINE_MASK = (L1_CACHE_BYTES-1)
 
 _GLOBAL(csum_partial_copy_generic)
-	stwu	r1,-16(r1)
-	stw	r7,12(r1)
-	stw	r8,8(r1)
-
-	addic	r12,r6,0
+	li	r12,-1
+	addic	r0,r0,0			/* clear carry */
 	addi	r6,r4,-4
 	neg	r0,r4
 	addi	r4,r3,-4
@@ -246,34 +241,19 @@ _GLOBAL(csum_partial_copy_generic)
 	rlwinm	r3,r3,8,0,31	/* odd destination address: rotate one byte */
 	blr
 
-/* read fault */
-src_error:
-	lwz	r7,12(r1)
-	addi	r1,r1,16
-	cmpwi	cr0,r7,0
-	beqlr
-	li	r0,-EFAULT
-	stw	r0,0(r7)
-	blr
-/* write fault */
-dst_error:
-	lwz	r8,8(r1)
-	addi	r1,r1,16
-	cmpwi	cr0,r8,0
-	beqlr
-	li	r0,-EFAULT
-	stw	r0,0(r8)
+fault:
+	li	r3,0
 	blr
 
-	EX_TABLE(70b, src_error);
-	EX_TABLE(71b, dst_error);
-	EX_TABLE(72b, src_error);
-	EX_TABLE(73b, dst_error);
-	EX_TABLE(54b, dst_error);
+	EX_TABLE(70b, fault);
+	EX_TABLE(71b, fault);
+	EX_TABLE(72b, fault);
+	EX_TABLE(73b, fault);
+	EX_TABLE(54b, fault);
 
 /*
  * this stuff handles faults in the cacheline loop and branches to either
- * src_error (if in read part) or dst_error (if in write part)
+ * fault (if in read part) or fault (if in write part)
  */
 	CSUM_COPY_16_BYTES_EXCODE(0)
 #if L1_CACHE_BYTES >= 32
@@ -290,12 +270,12 @@ dst_error:
 #endif
 #endif
 
-	EX_TABLE(30b, src_error);
-	EX_TABLE(31b, dst_error);
-	EX_TABLE(40b, src_error);
-	EX_TABLE(41b, dst_error);
-	EX_TABLE(50b, src_error);
-	EX_TABLE(51b, dst_error);
+	EX_TABLE(30b, fault);
+	EX_TABLE(31b, fault);
+	EX_TABLE(40b, fault);
+	EX_TABLE(41b, fault);
+	EX_TABLE(50b, fault);
+	EX_TABLE(51b, fault);
 
 EXPORT_SYMBOL(csum_partial_copy_generic)
 
diff --git a/arch/powerpc/lib/checksum_64.S b/arch/powerpc/lib/checksum_64.S
index 514978f908d4..98ff51bd2f7d 100644
--- a/arch/powerpc/lib/checksum_64.S
+++ b/arch/powerpc/lib/checksum_64.S
@@ -182,34 +182,33 @@ EXPORT_SYMBOL(__csum_partial)
 
 	.macro srcnr
 100:
-	EX_TABLE(100b,.Lsrc_error_nr)
+	EX_TABLE(100b,.Lerror_nr)
 	.endm
 
 	.macro source
 150:
-	EX_TABLE(150b,.Lsrc_error)
+	EX_TABLE(150b,.Lerror)
 	.endm
 
 	.macro dstnr
 200:
-	EX_TABLE(200b,.Ldest_error_nr)
+	EX_TABLE(200b,.Lerror_nr)
 	.endm
 
 	.macro dest
 250:
-	EX_TABLE(250b,.Ldest_error)
+	EX_TABLE(250b,.Lerror)
 	.endm
 
 /*
  * Computes the checksum of a memory block at src, length len,
- * and adds in "sum" (32-bit), while copying the block to dst.
- * If an access exception occurs on src or dst, it stores -EFAULT
- * to *src_err or *dst_err respectively. The caller must take any action
- * required in this case (zeroing memory, recalculating partial checksum etc).
+ * and adds in 0xffffffff (32-bit), while copying the block to dst.
+ * If an access exception occurs, it returns 0.
  *
- * csum_partial_copy_generic(r3=src, r4=dst, r5=len, r6=sum, r7=src_err, r8=dst_err)
+ * csum_partial_copy_generic(r3=src, r4=dst, r5=len)
  */
 _GLOBAL(csum_partial_copy_generic)
+	li	r6,-1
 	addic	r0,r6,0			/* clear carry */
 
 	srdi.	r6,r5,3			/* less than 8 bytes? */
@@ -401,29 +400,15 @@ dstnr;	stb	r6,0(r4)
 	srdi	r3,r3,32
 	blr
 
-.Lsrc_error:
+.Lerror:
 	ld	r14,STK_REG(R14)(r1)
 	ld	r15,STK_REG(R15)(r1)
 	ld	r16,STK_REG(R16)(r1)
 	addi	r1,r1,STACKFRAMESIZE
-.Lsrc_error_nr:
-	cmpdi	0,r7,0
-	beqlr
-	li	r6,-EFAULT
-	stw	r6,0(r7)
+.Lerror_nr:
+	li	r3,0
 	blr
 
-.Ldest_error:
-	ld	r14,STK_REG(R14)(r1)
-	ld	r15,STK_REG(R15)(r1)
-	ld	r16,STK_REG(R16)(r1)
-	addi	r1,r1,STACKFRAMESIZE
-.Ldest_error_nr:
-	cmpdi	0,r8,0
-	beqlr
-	li	r6,-EFAULT
-	stw	r6,0(r8)
-	blr
 EXPORT_SYMBOL(csum_partial_copy_generic)
 
 /*
diff --git a/arch/powerpc/lib/checksum_wrappers.c b/arch/powerpc/lib/checksum_wrappers.c
index b1faa82dd8af..b895166afc82 100644
--- a/arch/powerpc/lib/checksum_wrappers.c
+++ b/arch/powerpc/lib/checksum_wrappers.c
@@ -14,8 +14,7 @@
 __wsum csum_and_copy_from_user(const void __user *src, void *dst,
 			       int len)
 {
-	unsigned int csum;
-	int err = 0;
+	__wsum csum;
 
 	might_sleep();
 
@@ -24,27 +23,16 @@ __wsum csum_and_copy_from_user(const void __user *src, void *dst,
 
 	allow_read_from_user(src, len);
 
-	csum = csum_partial_copy_generic((void __force *)src, dst,
-					 len, ~0U, &err, NULL);
-
-	if (unlikely(err)) {
-		int missing = __copy_from_user(dst, src, len);
-
-		if (missing)
-			csum = 0;
-		else
-			csum = csum_partial(dst, len, ~0U);
-	}
+	csum = csum_partial_copy_generic((void __force *)src, dst, len);
 
 	prevent_read_from_user(src, len);
-	return (__force __wsum)csum;
+	return csum;
 }
 EXPORT_SYMBOL(csum_and_copy_from_user);
 
 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
 {
-	unsigned int csum;
-	int err = 0;
+	__wsum csum;
 
 	might_sleep();
 	if (unlikely(!access_ok(dst, len)))
@@ -52,17 +40,9 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
 
 	allow_write_to_user(dst, len);
 
-	csum = csum_partial_copy_generic(src, (void __force *)dst,
-					 len, ~0U, NULL, &err);
-
-	if (unlikely(err)) {
-		csum = csum_partial(src, len, ~0U);
-
-		if (copy_to_user(dst, src, len))
-			csum = 0;
-	}
+	csum = csum_partial_copy_generic(src, (void __force *)dst, len);
 
 	prevent_write_to_user(dst, len);
-	return (__force __wsum)csum;
+	return csum;
 }
 EXPORT_SYMBOL(csum_and_copy_to_user);