diff options
| author | Jan Beulich <JBeulich@suse.com> | 2012-01-05 16:10:42 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2012-01-26 11:50:04 +0100 |
| commit | 5d7244e7c984cecead412bde6395ce18618a4a37 (patch) | |
| tree | d1b468fe47733ab3770f127d44d04ac2937965ee | |
| parent | 426932909093e4e7729777a0e2beed4b54911361 (diff) | |
x86-64: Fix memset() 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 memset()
(alloc_bootmem() being the primary non-reachable one, as it gets
called with suitably large sizes in FLATMEM configurations), we
have recently hit the problem a second time in our Xen kernels.
Rather than working around it a second time, 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>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/4F05D992020000780006AA09@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/lib/memset_64.S | 33 |
1 files changed, 15 insertions, 18 deletions
diff --git a/arch/x86/lib/memset_64.S b/arch/x86/lib/memset_64.S index 79bd454b78a..2dcb3808cbd 100644 --- a/arch/x86/lib/memset_64.S +++ b/arch/x86/lib/memset_64.S @@ -19,16 +19,15 @@ .section .altinstr_replacement, "ax", @progbits .Lmemset_c: movq %rdi,%r9 - movl %edx,%r8d - andl $7,%r8d - movl %edx,%ecx - shrl $3,%ecx + movq %rdx,%rcx + andl $7,%edx + shrq $3,%rcx /* expand byte value */ movzbl %sil,%esi movabs $0x0101010101010101,%rax - mulq %rsi /* with rax, clobbers rdx */ + imulq %rsi,%rax rep stosq - movl %r8d,%ecx + movl %edx,%ecx rep stosb movq %r9,%rax ret @@ -50,7 +49,7 @@ .Lmemset_c_e: movq %rdi,%r9 movb %sil,%al - movl %edx,%ecx + movq %rdx,%rcx rep stosb movq %r9,%rax ret @@ -61,12 +60,11 @@ ENTRY(memset) ENTRY(__memset) CFI_STARTPROC movq %rdi,%r10 - movq %rdx,%r11 /* expand byte value */ movzbl %sil,%ecx movabs $0x0101010101010101,%rax - mul %rcx /* with rax, clobbers rdx */ + imulq %rcx,%rax /* align dst */ movl %edi,%r9d @@ -75,13 +73,13 @@ ENTRY(__memset) CFI_REMEMBER_STATE .Lafter_bad_alignment: - movl %r11d,%ecx - shrl $6,%ecx + movq %rdx,%rcx + shrq $6,%rcx jz .Lhandle_tail .p2align 4 .Lloop_64: - decl %ecx + decq %rcx movq %rax,(%rdi) movq %rax,8(%rdi) movq %rax,16(%rdi) @@ -97,7 +95,7 @@ ENTRY(__memset) to predict jump tables. */ .p2align 4 .Lhandle_tail: - movl %r11d,%ecx + movl %edx,%ecx andl $63&(~7),%ecx jz .Lhandle_7 shrl $3,%ecx @@ -109,12 +107,11 @@ ENTRY(__memset) jnz .Lloop_8 .Lhandle_7: - movl %r11d,%ecx - andl $7,%ecx + andl $7,%edx jz .Lende .p2align 4 .Lloop_1: - decl %ecx + decl %edx movb %al,(%rdi) leaq 1(%rdi),%rdi jnz .Lloop_1 @@ -125,13 +122,13 @@ ENTRY(__memset) CFI_RESTORE_STATE .Lbad_alignment: - cmpq $7,%r11 + cmpq $7,%rdx jbe .Lhandle_7 movq %rax,(%rdi) /* unaligned store */ movq $8,%r8 subq %r9,%r8 addq %r8,%rdi - subq %r8,%r11 + subq %r8,%rdx jmp .Lafter_bad_alignment .Lfinal: CFI_ENDPROC |