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linux/arch/sparc/lib/memmove.S

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Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* memmove.S: Simple memmove implementation.
*
* Copyright (C) 1997, 2004 David S. Miller (davem@redhat.com)
* Copyright (C) 1996, 1997, 1998, 1999 Jakub Jelinek (jj@ultra.linux.cz)
*/
sparc: Convert some assembler over to linakge.h's ENTRY/ENDPROC Use those, instead of doing it all by hand. Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-12 11:33:22 +08:00
#include <linux/linkage.h>
sparc: move exports to definitions Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-17 10:39:30 +08:00
#include <asm/export.h>
sparc: Convert some assembler over to linakge.h's ENTRY/ENDPROC Use those, instead of doing it all by hand. Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-12 11:33:22 +08:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
.text
sparc: Convert some assembler over to linakge.h's ENTRY/ENDPROC Use those, instead of doing it all by hand. Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-12 11:33:22 +08:00
ENTRY(memmove) /* o0=dst o1=src o2=len */
sparc64: Fix several bugs in memmove(). Firstly, handle zero length calls properly. Believe it or not there are a few of these happening during early boot. Next, we can't just drop to a memcpy() call in the forward copy case where dst <= src. The reason is that the cache initializing stores used in the Niagara memcpy() implementations can end up clearing out cache lines before we've sourced their original contents completely. For example, considering NG4memcpy, the main unrolled loop begins like this: load src + 0x00 load src + 0x08 load src + 0x10 load src + 0x18 load src + 0x20 store dst + 0x00 Assume dst is 64 byte aligned and let's say that dst is src - 8 for this memcpy() call. That store at the end there is the one to the first line in the cache line, thus clearing the whole line, which thus clobbers "src + 0x28" before it even gets loaded. To avoid this, just fall through to a simple copy only mildly optimized for the case where src and dst are 8 byte aligned and the length is a multiple of 8 as well. We could get fancy and call GENmemcpy() but this is good enough for how this thing is actually used. Reported-by: David Ahern <david.ahern@oracle.com> Reported-by: Bob Picco <bpicco@meloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-24 00:22:10 +08:00
brz,pn %o2, 99f
mov %o0, %g1
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
cmp %o0, %o1
sparc64: Fix several bugs in memmove(). Firstly, handle zero length calls properly. Believe it or not there are a few of these happening during early boot. Next, we can't just drop to a memcpy() call in the forward copy case where dst <= src. The reason is that the cache initializing stores used in the Niagara memcpy() implementations can end up clearing out cache lines before we've sourced their original contents completely. For example, considering NG4memcpy, the main unrolled loop begins like this: load src + 0x00 load src + 0x08 load src + 0x10 load src + 0x18 load src + 0x20 store dst + 0x00 Assume dst is 64 byte aligned and let's say that dst is src - 8 for this memcpy() call. That store at the end there is the one to the first line in the cache line, thus clearing the whole line, which thus clobbers "src + 0x28" before it even gets loaded. To avoid this, just fall through to a simple copy only mildly optimized for the case where src and dst are 8 byte aligned and the length is a multiple of 8 as well. We could get fancy and call GENmemcpy() but this is good enough for how this thing is actually used. Reported-by: David Ahern <david.ahern@oracle.com> Reported-by: Bob Picco <bpicco@meloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-24 00:22:10 +08:00
bleu,pt %xcc, 2f
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
add %o1, %o2, %g7
cmp %g7, %o0
bleu,pt %xcc, memcpy
add %o0, %o2, %o5
sub %g7, 1, %o1
sub %o5, 1, %o0
1: ldub [%o1], %g7
subcc %o2, 1, %o2
sub %o1, 1, %o1
stb %g7, [%o0]
bne,pt %icc, 1b
sub %o0, 1, %o0
sparc64: Fix several bugs in memmove(). Firstly, handle zero length calls properly. Believe it or not there are a few of these happening during early boot. Next, we can't just drop to a memcpy() call in the forward copy case where dst <= src. The reason is that the cache initializing stores used in the Niagara memcpy() implementations can end up clearing out cache lines before we've sourced their original contents completely. For example, considering NG4memcpy, the main unrolled loop begins like this: load src + 0x00 load src + 0x08 load src + 0x10 load src + 0x18 load src + 0x20 store dst + 0x00 Assume dst is 64 byte aligned and let's say that dst is src - 8 for this memcpy() call. That store at the end there is the one to the first line in the cache line, thus clearing the whole line, which thus clobbers "src + 0x28" before it even gets loaded. To avoid this, just fall through to a simple copy only mildly optimized for the case where src and dst are 8 byte aligned and the length is a multiple of 8 as well. We could get fancy and call GENmemcpy() but this is good enough for how this thing is actually used. Reported-by: David Ahern <david.ahern@oracle.com> Reported-by: Bob Picco <bpicco@meloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-24 00:22:10 +08:00
99:
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
retl
mov %g1, %o0
sparc64: Fix several bugs in memmove(). Firstly, handle zero length calls properly. Believe it or not there are a few of these happening during early boot. Next, we can't just drop to a memcpy() call in the forward copy case where dst <= src. The reason is that the cache initializing stores used in the Niagara memcpy() implementations can end up clearing out cache lines before we've sourced their original contents completely. For example, considering NG4memcpy, the main unrolled loop begins like this: load src + 0x00 load src + 0x08 load src + 0x10 load src + 0x18 load src + 0x20 store dst + 0x00 Assume dst is 64 byte aligned and let's say that dst is src - 8 for this memcpy() call. That store at the end there is the one to the first line in the cache line, thus clearing the whole line, which thus clobbers "src + 0x28" before it even gets loaded. To avoid this, just fall through to a simple copy only mildly optimized for the case where src and dst are 8 byte aligned and the length is a multiple of 8 as well. We could get fancy and call GENmemcpy() but this is good enough for how this thing is actually used. Reported-by: David Ahern <david.ahern@oracle.com> Reported-by: Bob Picco <bpicco@meloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-24 00:22:10 +08:00
/* We can't just call memcpy for these memmove cases. On some
* chips the memcpy uses cache initializing stores and when dst
* and src are close enough, those can clobber the source data
* before we've loaded it in.
*/
2: or %o0, %o1, %g7
or %o2, %g7, %g7
andcc %g7, 0x7, %g0
bne,pn %xcc, 4f
nop
3: ldx [%o1], %g7
add %o1, 8, %o1
subcc %o2, 8, %o2
add %o0, 8, %o0
bne,pt %icc, 3b
stx %g7, [%o0 - 0x8]
ba,a,pt %xcc, 99b
4: ldub [%o1], %g7
add %o1, 1, %o1
subcc %o2, 1, %o2
add %o0, 1, %o0
bne,pt %icc, 4b
stb %g7, [%o0 - 0x1]
ba,a,pt %xcc, 99b
sparc: Convert some assembler over to linakge.h's ENTRY/ENDPROC Use those, instead of doing it all by hand. Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-12 11:33:22 +08:00
ENDPROC(memmove)
sparc: move exports to definitions Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-17 10:39:30 +08:00
EXPORT_SYMBOL(memmove)
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