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4d6ffa27b8
Commit393f203f5f("x86_64: kasan: add interceptors for memset/memmove/memcpy functions") added .weak directives to arch/x86/lib/mem*_64.S instead of changing the existing ENTRY macros to WEAK. This can lead to the assembly snippet .weak memcpy ... .globl memcpy which will produce a STB_WEAK memcpy with GNU as but STB_GLOBAL memcpy with LLVM's integrated assembler before LLVM 12. LLVM 12 (since https://reviews.llvm.org/D90108) will error on such an overridden symbol binding. Commitef1e03152c("x86/asm: Make some functions local") changed ENTRY in arch/x86/lib/memcpy_64.S to SYM_FUNC_START_LOCAL, which was ineffective due to the preceding .weak directive. Use the appropriate SYM_FUNC_START_WEAK instead. Fixes:393f203f5f("x86_64: kasan: add interceptors for memset/memmove/memcpy functions") Fixes:ef1e03152c("x86/asm: Make some functions local") Reported-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Fangrui Song <maskray@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20201103012358.168682-1-maskray@google.com
140 lines
2.8 KiB
ArmAsm
140 lines
2.8 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright 2002 Andi Kleen, SuSE Labs */
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#include <linux/linkage.h>
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#include <asm/cpufeatures.h>
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#include <asm/alternative-asm.h>
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#include <asm/export.h>
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/*
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* ISO C memset - set a memory block to a byte value. This function uses fast
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* string to get better performance than the original function. The code is
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* simpler and shorter than the original function as well.
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*
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* rdi destination
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* rsi value (char)
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* rdx count (bytes)
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*
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* rax original destination
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*/
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SYM_FUNC_START_WEAK(memset)
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SYM_FUNC_START(__memset)
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/*
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* Some CPUs support enhanced REP MOVSB/STOSB feature. It is recommended
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* to use it when possible. If not available, use fast string instructions.
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*
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* Otherwise, use original memset function.
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*/
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ALTERNATIVE_2 "jmp memset_orig", "", X86_FEATURE_REP_GOOD, \
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"jmp memset_erms", X86_FEATURE_ERMS
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movq %rdi,%r9
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movq %rdx,%rcx
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andl $7,%edx
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shrq $3,%rcx
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/* expand byte value */
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movzbl %sil,%esi
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movabs $0x0101010101010101,%rax
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imulq %rsi,%rax
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rep stosq
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movl %edx,%ecx
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rep stosb
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movq %r9,%rax
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ret
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SYM_FUNC_END(__memset)
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SYM_FUNC_END_ALIAS(memset)
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EXPORT_SYMBOL(memset)
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EXPORT_SYMBOL(__memset)
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/*
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* ISO C memset - set a memory block to a byte value. This function uses
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* enhanced rep stosb to override the fast string function.
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* The code is simpler and shorter than the fast string function as well.
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*
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* rdi destination
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* rsi value (char)
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* rdx count (bytes)
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*
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* rax original destination
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*/
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SYM_FUNC_START_LOCAL(memset_erms)
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movq %rdi,%r9
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movb %sil,%al
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movq %rdx,%rcx
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rep stosb
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movq %r9,%rax
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ret
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SYM_FUNC_END(memset_erms)
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SYM_FUNC_START_LOCAL(memset_orig)
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movq %rdi,%r10
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/* expand byte value */
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movzbl %sil,%ecx
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movabs $0x0101010101010101,%rax
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imulq %rcx,%rax
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/* align dst */
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movl %edi,%r9d
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andl $7,%r9d
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jnz .Lbad_alignment
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.Lafter_bad_alignment:
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movq %rdx,%rcx
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shrq $6,%rcx
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jz .Lhandle_tail
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.p2align 4
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.Lloop_64:
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decq %rcx
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movq %rax,(%rdi)
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movq %rax,8(%rdi)
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movq %rax,16(%rdi)
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movq %rax,24(%rdi)
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movq %rax,32(%rdi)
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movq %rax,40(%rdi)
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movq %rax,48(%rdi)
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movq %rax,56(%rdi)
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leaq 64(%rdi),%rdi
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jnz .Lloop_64
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/* Handle tail in loops. The loops should be faster than hard
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to predict jump tables. */
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.p2align 4
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.Lhandle_tail:
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movl %edx,%ecx
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andl $63&(~7),%ecx
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jz .Lhandle_7
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shrl $3,%ecx
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.p2align 4
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.Lloop_8:
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decl %ecx
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movq %rax,(%rdi)
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leaq 8(%rdi),%rdi
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jnz .Lloop_8
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.Lhandle_7:
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andl $7,%edx
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jz .Lende
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.p2align 4
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.Lloop_1:
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decl %edx
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movb %al,(%rdi)
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leaq 1(%rdi),%rdi
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jnz .Lloop_1
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.Lende:
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movq %r10,%rax
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ret
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.Lbad_alignment:
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cmpq $7,%rdx
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jbe .Lhandle_7
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movq %rax,(%rdi) /* unaligned store */
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movq $8,%r8
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subq %r9,%r8
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addq %r8,%rdi
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subq %r8,%rdx
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jmp .Lafter_bad_alignment
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.Lfinal:
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SYM_FUNC_END(memset_orig)
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