Commit-ID: 2ab560911a427fdc73bfd3a7d2944d8ee0ca6db8 Gitweb: http://git.kernel.org/tip/2ab560911a427fdc73bfd3a7d2944d8ee0ca6db8 Author: Jan Beulich <JBeulich@xxxxxxxx> AuthorDate: Thu, 26 Jan 2012 15:50:55 +0000 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Thu, 26 Jan 2012 21:19:18 +0100 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@xxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/4F21846F020000780006F3FA@xxxxxxxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- 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 efbf2a0..1235b04 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 /* -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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