![Andrey Ryabinin](/assets/img/avatar_default.png)
Recently instrumentation of builtin functions calls was removed from GCC 5.0. To check the memory accessed by such functions, userspace asan always uses interceptors for them. So now we should do this as well. This patch declares memset/memmove/memcpy as weak symbols. In mm/kasan/kasan.c we have our own implementation of those functions which checks memory before accessing it. Default memset/memmove/memcpy now now always have aliases with '__' prefix. For files that built without kasan instrumentation (e.g. mm/slub.c) original mem* replaced (via #define) with prefixed variants, cause we don't want to check memory accesses there. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
157 lines
3.1 KiB
ArmAsm
157 lines
3.1 KiB
ArmAsm
/* Copyright 2002 Andi Kleen, SuSE Labs */
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#include <linux/linkage.h>
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#include <asm/dwarf2.h>
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#include <asm/cpufeature.h>
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#include <asm/alternative-asm.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 orignal 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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.section .altinstr_replacement, "ax", @progbits
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.Lmemset_c:
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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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.Lmemset_e:
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.previous
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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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.section .altinstr_replacement, "ax", @progbits
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.Lmemset_c_e:
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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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.Lmemset_e_e:
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.previous
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.weak memset
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ENTRY(memset)
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ENTRY(__memset)
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CFI_STARTPROC
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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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CFI_REMEMBER_STATE
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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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CFI_RESTORE_STATE
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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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CFI_ENDPROC
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ENDPROC(memset)
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ENDPROC(__memset)
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/* Some CPUs support enhanced REP MOVSB/STOSB feature.
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* It is recommended to use this when possible.
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*
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* If enhanced REP MOVSB/STOSB feature is not available, use fast string
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* instructions.
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*
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* Otherwise, use original memset function.
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*
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* In .altinstructions section, ERMS feature is placed after REG_GOOD
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* feature to implement the right patch order.
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*/
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.section .altinstructions,"a"
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altinstruction_entry __memset,.Lmemset_c,X86_FEATURE_REP_GOOD,\
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.Lfinal-__memset,.Lmemset_e-.Lmemset_c
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altinstruction_entry __memset,.Lmemset_c_e,X86_FEATURE_ERMS, \
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.Lfinal-__memset,.Lmemset_e_e-.Lmemset_c_e
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.previous
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