linux/arch/hexagon/lib/checksum.c
Al Viro 6e41c585e3 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>
2020-08-20 15:45:14 -04:00

179 lines
4.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Checksum functions for Hexagon
*
* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
*/
/* This was derived from arch/alpha/lib/checksum.c */
#include <linux/module.h>
#include <linux/string.h>
#include <asm/byteorder.h>
#include <net/checksum.h>
#include <linux/uaccess.h>
#include <asm/intrinsics.h>
/* Vector value operations */
#define SIGN(x, y) ((0x8000ULL*x)<<y)
#define CARRY(x, y) ((0x0002ULL*x)<<y)
#define SELECT(x, y) ((0x0001ULL*x)<<y)
#define VR_NEGATE(a, b, c, d) (SIGN(a, 48) + SIGN(b, 32) + SIGN(c, 16) \
+ SIGN(d, 0))
#define VR_CARRY(a, b, c, d) (CARRY(a, 48) + CARRY(b, 32) + CARRY(c, 16) \
+ CARRY(d, 0))
#define VR_SELECT(a, b, c, d) (SELECT(a, 48) + SELECT(b, 32) + SELECT(c, 16) \
+ SELECT(d, 0))
/* optimized HEXAGON V3 intrinsic version */
static inline unsigned short from64to16(u64 x)
{
u64 sum;
sum = HEXAGON_P_vrmpyh_PP(x^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
sum += VR_CARRY(0, 0, 1, 0);
sum = HEXAGON_P_vrmpyh_PP(sum, VR_SELECT(0, 0, 1, 1));
return 0xFFFF & sum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented.
*/
__sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
__u32 len, __u8 proto, __wsum sum)
{
return (__force __sum16)~from64to16(
(__force u64)saddr + (__force u64)daddr +
(__force u64)sum + ((len + proto) << 8));
}
__wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
__u32 len, __u8 proto, __wsum sum)
{
u64 result;
result = (__force u64)saddr + (__force u64)daddr +
(__force u64)sum + ((len + proto) << 8);
/* Fold down to 32-bits so we don't lose in the typedef-less
network stack. */
/* 64 to 33 */
result = (result & 0xffffffffUL) + (result >> 32);
/* 33 to 32 */
result = (result & 0xffffffffUL) + (result >> 32);
return (__force __wsum)result;
}
EXPORT_SYMBOL(csum_tcpudp_nofold);
/*
* Do a 64-bit checksum on an arbitrary memory area..
*
* This isn't a great routine, but it's not _horrible_ either. The
* inner loop could be unrolled a bit further, and there are better
* ways to do the carry, but this is reasonable.
*/
/* optimized HEXAGON intrinsic version, with over read fixed */
unsigned int do_csum(const void *voidptr, int len)
{
u64 sum0, sum1, x0, x1, *ptr8_o, *ptr8_e, *ptr8;
int i, start, mid, end, mask;
const char *ptr = voidptr;
unsigned short *ptr2;
unsigned int *ptr4;
if (len <= 0)
return 0;
start = 0xF & (16-(((int) ptr) & 0xF)) ;
mask = 0x7fffffffUL >> HEXAGON_R_cl0_R(len);
start = start & mask ;
mid = len - start;
end = mid & 0xF;
mid = mid>>4;
sum0 = mid << 18;
sum1 = 0;
if (start & 1)
sum0 += (u64) (ptr[0] << 8);
ptr2 = (unsigned short *) &ptr[start & 1];
if (start & 2)
sum1 += (u64) ptr2[0];
ptr4 = (unsigned int *) &ptr[start & 3];
if (start & 4) {
sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
VR_SELECT(0, 0, 1, 1));
sum0 += VR_SELECT(0, 0, 1, 0);
}
ptr8 = (u64 *) &ptr[start & 7];
if (start & 8) {
sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
VR_SELECT(1, 1, 1, 1));
sum1 += VR_CARRY(0, 0, 1, 0);
}
ptr8_o = (u64 *) (ptr + start);
ptr8_e = (u64 *) (ptr + start + 8);
if (mid) {
x0 = *ptr8_e; ptr8_e += 2;
x1 = *ptr8_o; ptr8_o += 2;
if (mid > 1)
for (i = 0; i < mid-1; i++) {
sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
x0^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
x1^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
x0 = *ptr8_e; ptr8_e += 2;
x1 = *ptr8_o; ptr8_o += 2;
}
sum0 = HEXAGON_P_vrmpyhacc_PP(sum0, x0^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
sum1 = HEXAGON_P_vrmpyhacc_PP(sum1, x1^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
}
ptr4 = (unsigned int *) &ptr[start + (mid * 16) + (end & 8)];
if (end & 4) {
sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
VR_SELECT(0, 0, 1, 1));
sum1 += VR_SELECT(0, 0, 1, 0);
}
ptr2 = (unsigned short *) &ptr[start + (mid * 16) + (end & 12)];
if (end & 2)
sum0 += (u64) ptr2[0];
if (end & 1)
sum1 += (u64) ptr[start + (mid * 16) + (end & 14)];
ptr8 = (u64 *) &ptr[start + (mid * 16)];
if (end & 8) {
sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
VR_SELECT(1, 1, 1, 1));
sum0 += VR_CARRY(0, 0, 1, 0);
}
sum0 = HEXAGON_P_vrmpyh_PP((sum0+sum1)^VR_NEGATE(0, 0, 0, 1),
VR_SELECT(0, 0, 1, 1));
sum0 += VR_NEGATE(0, 0, 0, 1);
sum0 = HEXAGON_P_vrmpyh_PP(sum0, VR_SELECT(0, 0, 1, 1));
if (start & 1)
sum0 = (sum0 << 8) | (0xFF & (sum0 >> 8));
return 0xFFFF & sum0;
}