mirror of https://gitee.com/openkylin/linux.git
54 lines
1.1 KiB
ArmAsm
54 lines
1.1 KiB
ArmAsm
/*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; version 2
|
|
* of the License.
|
|
*
|
|
*/
|
|
#include <linux/linkage.h>
|
|
#include <asm/percpu.h>
|
|
|
|
.text
|
|
|
|
/*
|
|
* Inputs:
|
|
* %rsi : memory location to compare
|
|
* %rax : low 64 bits of old value
|
|
* %rdx : high 64 bits of old value
|
|
* %rbx : low 64 bits of new value
|
|
* %rcx : high 64 bits of new value
|
|
* %al : Operation successful
|
|
*/
|
|
ENTRY(this_cpu_cmpxchg16b_emu)
|
|
|
|
#
|
|
# Emulate 'cmpxchg16b %gs:(%rsi)' except we return the result in %al not
|
|
# via the ZF. Caller will access %al to get result.
|
|
#
|
|
# Note that this is only useful for a cpuops operation. Meaning that we
|
|
# do *not* have a fully atomic operation but just an operation that is
|
|
# *atomic* on a single cpu (as provided by the this_cpu_xx class of
|
|
# macros).
|
|
#
|
|
pushfq
|
|
cli
|
|
|
|
cmpq PER_CPU_VAR((%rsi)), %rax
|
|
jne .Lnot_same
|
|
cmpq PER_CPU_VAR(8(%rsi)), %rdx
|
|
jne .Lnot_same
|
|
|
|
movq %rbx, PER_CPU_VAR((%rsi))
|
|
movq %rcx, PER_CPU_VAR(8(%rsi))
|
|
|
|
popfq
|
|
mov $1, %al
|
|
ret
|
|
|
|
.Lnot_same:
|
|
popfq
|
|
xor %al,%al
|
|
ret
|
|
|
|
ENDPROC(this_cpu_cmpxchg16b_emu)
|