mirror of
https://github.com/torvalds/linux.git
synced 2026-04-18 14:53:58 -04:00
2981557cb0
The expectation is that all EXPORT'ed symbols are free to have their address taken and called indirectly. The majority of the assembly defined functions currently violate this expectation. Make then all use SYM_TYPED_FUNC_START() in order to emit the proper kCFI preamble. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20250207122546.302679189@infradead.org
119 lines
2.4 KiB
ArmAsm
119 lines
2.4 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/* Copyright 2002 Andi Kleen, SuSE Labs */
|
|
|
|
#include <linux/export.h>
|
|
#include <linux/linkage.h>
|
|
#include <linux/cfi_types.h>
|
|
#include <asm/cpufeatures.h>
|
|
#include <asm/alternative.h>
|
|
|
|
.section .noinstr.text, "ax"
|
|
|
|
/*
|
|
* ISO C memset - set a memory block to a byte value. This function uses fast
|
|
* string to get better performance than the original function. The code is
|
|
* simpler and shorter than the original function as well.
|
|
*
|
|
* rdi destination
|
|
* rsi value (char)
|
|
* rdx count (bytes)
|
|
*
|
|
* rax original destination
|
|
*
|
|
* The FSRS alternative should be done inline (avoiding the call and
|
|
* the disgusting return handling), but that would require some help
|
|
* from the compiler for better calling conventions.
|
|
*
|
|
* The 'rep stosb' itself is small enough to replace the call, but all
|
|
* the register moves blow up the code. And two of them are "needed"
|
|
* only for the return value that is the same as the source input,
|
|
* which the compiler could/should do much better anyway.
|
|
*/
|
|
SYM_TYPED_FUNC_START(__memset)
|
|
ALTERNATIVE "jmp memset_orig", "", X86_FEATURE_FSRS
|
|
|
|
movq %rdi,%r9
|
|
movb %sil,%al
|
|
movq %rdx,%rcx
|
|
rep stosb
|
|
movq %r9,%rax
|
|
RET
|
|
SYM_FUNC_END(__memset)
|
|
EXPORT_SYMBOL(__memset)
|
|
|
|
SYM_FUNC_ALIAS_MEMFUNC(memset, __memset)
|
|
EXPORT_SYMBOL(memset)
|
|
|
|
SYM_FUNC_START_LOCAL(memset_orig)
|
|
movq %rdi,%r10
|
|
|
|
/* expand byte value */
|
|
movzbl %sil,%ecx
|
|
movabs $0x0101010101010101,%rax
|
|
imulq %rcx,%rax
|
|
|
|
/* align dst */
|
|
movl %edi,%r9d
|
|
andl $7,%r9d
|
|
jnz .Lbad_alignment
|
|
.Lafter_bad_alignment:
|
|
|
|
movq %rdx,%rcx
|
|
shrq $6,%rcx
|
|
jz .Lhandle_tail
|
|
|
|
.p2align 4
|
|
.Lloop_64:
|
|
decq %rcx
|
|
movq %rax,(%rdi)
|
|
movq %rax,8(%rdi)
|
|
movq %rax,16(%rdi)
|
|
movq %rax,24(%rdi)
|
|
movq %rax,32(%rdi)
|
|
movq %rax,40(%rdi)
|
|
movq %rax,48(%rdi)
|
|
movq %rax,56(%rdi)
|
|
leaq 64(%rdi),%rdi
|
|
jnz .Lloop_64
|
|
|
|
/* Handle tail in loops. The loops should be faster than hard
|
|
to predict jump tables. */
|
|
.p2align 4
|
|
.Lhandle_tail:
|
|
movl %edx,%ecx
|
|
andl $63&(~7),%ecx
|
|
jz .Lhandle_7
|
|
shrl $3,%ecx
|
|
.p2align 4
|
|
.Lloop_8:
|
|
decl %ecx
|
|
movq %rax,(%rdi)
|
|
leaq 8(%rdi),%rdi
|
|
jnz .Lloop_8
|
|
|
|
.Lhandle_7:
|
|
andl $7,%edx
|
|
jz .Lende
|
|
.p2align 4
|
|
.Lloop_1:
|
|
decl %edx
|
|
movb %al,(%rdi)
|
|
leaq 1(%rdi),%rdi
|
|
jnz .Lloop_1
|
|
|
|
.Lende:
|
|
movq %r10,%rax
|
|
RET
|
|
|
|
.Lbad_alignment:
|
|
cmpq $7,%rdx
|
|
jbe .Lhandle_7
|
|
movq %rax,(%rdi) /* unaligned store */
|
|
movq $8,%r8
|
|
subq %r9,%r8
|
|
addq %r8,%rdi
|
|
subq %r8,%rdx
|
|
jmp .Lafter_bad_alignment
|
|
.Lfinal:
|
|
SYM_FUNC_END(memset_orig)
|