diff options
| author | Jan Beulich <JBeulich@suse.com> | 2012-01-26 15:50:55 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2012-01-26 21:19:18 +0100 |
| commit | 2ab560911a427fdc73bfd3a7d2944d8ee0ca6db8 (patch) | |
| tree | 1e7d65a8a0589347da02629feaa315adff6aea8e | |
| parent | 5d7244e7c984cecead412bde6395ce18618a4a37 (diff) | |
x86-64: Fix memcpy() to support sizes of 4Gb and above
While currently there doesn't appear to be any reachable in-tree
case where such large memory blocks may be passed to memcpy(),
we already had hit the problem in our Xen kernels. Just like
done recently for mmeset(), rather than working around it,
prevent others from falling into the same trap by fixing this
long standing limitation.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/4F21846F020000780006F3FA@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/lib/memcpy_64.S | 25 |
1 files changed, 10 insertions, 15 deletions
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S index efbf2a0ecde..1235b04a9a6 100644 --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -27,9 +27,8 @@ .section .altinstr_replacement, "ax", @progbits .Lmemcpy_c: movq %rdi, %rax - - movl %edx, %ecx - shrl $3, %ecx + movq %rdx, %rcx + shrq $3, %rcx andl $7, %edx rep movsq movl %edx, %ecx @@ -48,8 +47,7 @@ .section .altinstr_replacement, "ax", @progbits .Lmemcpy_c_e: movq %rdi, %rax - - movl %edx, %ecx + movq %rdx, %rcx rep movsb ret .Lmemcpy_e_e: @@ -60,10 +58,7 @@ ENTRY(memcpy) CFI_STARTPROC movq %rdi, %rax - /* - * Use 32bit CMP here to avoid long NOP padding. - */ - cmp $0x20, %edx + cmpq $0x20, %rdx jb .Lhandle_tail /* @@ -72,7 +67,7 @@ ENTRY(memcpy) */ cmp %dil, %sil jl .Lcopy_backward - subl $0x20, %edx + subq $0x20, %rdx .Lcopy_forward_loop: subq $0x20, %rdx @@ -91,7 +86,7 @@ ENTRY(memcpy) movq %r11, 3*8(%rdi) leaq 4*8(%rdi), %rdi jae .Lcopy_forward_loop - addq $0x20, %rdx + addl $0x20, %edx jmp .Lhandle_tail .Lcopy_backward: @@ -123,11 +118,11 @@ ENTRY(memcpy) /* * Calculate copy position to head. */ - addq $0x20, %rdx + addl $0x20, %edx subq %rdx, %rsi subq %rdx, %rdi .Lhandle_tail: - cmpq $16, %rdx + cmpl $16, %edx jb .Lless_16bytes /* @@ -144,7 +139,7 @@ ENTRY(memcpy) retq .p2align 4 .Lless_16bytes: - cmpq $8, %rdx + cmpl $8, %edx jb .Lless_8bytes /* * Move data from 8 bytes to 15 bytes. @@ -156,7 +151,7 @@ ENTRY(memcpy) retq .p2align 4 .Lless_8bytes: - cmpq $4, %rdx + cmpl $4, %edx jb .Lless_3bytes /* |