linux/arch/x86/lib/cmpxchg8b_emu.S
Peter Zijlstra 6d12c8d308 percpu: Wire up cmpxchg128
In order to replace cmpxchg_double() with the newly minted
cmpxchg128() family of functions, wire it up in this_cpu_cmpxchg().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230531132323.654945124@infradead.org
2023-06-05 09:36:37 +02:00

86 lines
1.2 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
#include <linux/linkage.h>
#include <asm/export.h>
#include <asm/percpu.h>
#include <asm/processor-flags.h>
.text
#ifndef CONFIG_X86_CMPXCHG64
/*
* Emulate 'cmpxchg8b (%esi)' on UP
*
* 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)
pushfl
cli
cmpl 0(%esi), %eax
jne .Lnot_same
cmpl 4(%esi), %edx
jne .Lnot_same
movl %ebx, 0(%esi)
movl %ecx, 4(%esi)
orl $X86_EFLAGS_ZF, (%esp)
popfl
RET
.Lnot_same:
movl 0(%esi), %eax
movl 4(%esi), %edx
andl $(~X86_EFLAGS_ZF), (%esp)
popfl
RET
SYM_FUNC_END(cmpxchg8b_emu)
EXPORT_SYMBOL(cmpxchg8b_emu)
#endif
#ifndef CONFIG_UML
SYM_FUNC_START(this_cpu_cmpxchg8b_emu)
pushfl
cli
cmpl PER_CPU_VAR(0(%esi)), %eax
jne .Lnot_same2
cmpl PER_CPU_VAR(4(%esi)), %edx
jne .Lnot_same2
movl %ebx, PER_CPU_VAR(0(%esi))
movl %ecx, PER_CPU_VAR(4(%esi))
orl $X86_EFLAGS_ZF, (%esp)
popfl
RET
.Lnot_same2:
movl PER_CPU_VAR(0(%esi)), %eax
movl PER_CPU_VAR(4(%esi)), %edx
andl $(~X86_EFLAGS_ZF), (%esp)
popfl
RET
SYM_FUNC_END(this_cpu_cmpxchg8b_emu)
#endif