linux/arch/x86/lib/cmpxchg8b_emu.S
Peter Zijlstra f94909ceb1 x86: Prepare asm files for straight-line-speculation
Replace all ret/retq instructions with RET in preparation of making
RET a macro. Since AS is case insensitive it's a big no-op without
RET defined.

  find arch/x86/ -name \*.S | while read file
  do
	sed -i 's/\<ret[q]*\>/RET/' $file
  done

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211204134907.905503893@infradead.org
2021-12-08 12:25:37 +01:00

47 lines
751 B
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
#include <linux/linkage.h>
#include <asm/export.h>
.text
/*
* Inputs:
* %esi : memory location to compare
* %eax : low 32 bits of old value
* %edx : high 32 bits of old value
* %ebx : low 32 bits of new value
* %ecx : high 32 bits of new value
*/
SYM_FUNC_START(cmpxchg8b_emu)
#
# Emulate 'cmpxchg8b (%esi)' on UP except we don't
# set the whole ZF thing (caller will just compare
# eax:edx with the expected value)
#
pushfl
cli
cmpl (%esi), %eax
jne .Lnot_same
cmpl 4(%esi), %edx
jne .Lhalf_same
movl %ebx, (%esi)
movl %ecx, 4(%esi)
popfl
RET
.Lnot_same:
movl (%esi), %eax
.Lhalf_same:
movl 4(%esi), %edx
popfl
RET
SYM_FUNC_END(cmpxchg8b_emu)
EXPORT_SYMBOL(cmpxchg8b_emu)