[deliverable/linux.git] / arch / x86 / lib / cmpxchg16b_emu.S

/*
 *	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/dwarf2.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)
CFI_STARTPROC

#
# 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_cfi
	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))

	CFI_REMEMBER_STATE
	popfq_cfi
	mov $1, %al
	ret

	CFI_RESTORE_STATE
.Lnot_same:
	popfq_cfi
	xor %al,%al
	ret

CFI_ENDPROC

ENDPROC(this_cpu_cmpxchg16b_emu)
Commit	Line	Data
b9ec40af CL	1	/*
	2	* This program is free software; you can redistribute it and/or
	3	* modify it under the terms of the GNU General Public License
	4	* as published by the Free Software Foundation; version 2
	5	* of the License.
	6	*
	7	*/
	8	#include <linux/linkage.h>
b9ec40af	9	#include <asm/dwarf2.h>
3f635721	10	#include <asm/percpu.h>
d7c3f8ce	11
b9ec40af CL	12	.text
	13
	14	/*
	15	* Inputs:
	16	* %rsi : memory location to compare
	17	* %rax : low 64 bits of old value
	18	* %rdx : high 64 bits of old value
	19	* %rbx : low 64 bits of new value
	20	* %rcx : high 64 bits of new value
	21	* %al : Operation successful
	22	*/
	23	ENTRY(this_cpu_cmpxchg16b_emu)
	24	CFI_STARTPROC
	25
	26	#
	27	# Emulate 'cmpxchg16b %gs:(%rsi)' except we return the result in %al not
	28	# via the ZF. Caller will access %al to get result.
	29	#
	30	# Note that this is only useful for a cpuops operation. Meaning that we
	31	# do not have a fully atomic operation but just an operation that is
	32	# atomic on a single cpu (as provided by the this_cpu_xx class of
	33	# macros).
	34	#
3f635721	35	pushfq_cfi
b9ec40af CL	36	cli
b9ec40af CL	37
3f635721 JB	38	cmpq PER_CPU_VAR((%rsi)), %rax
	39	jne .Lnot_same
	40	cmpq PER_CPU_VAR(8(%rsi)), %rdx
	41	jne .Lnot_same
b9ec40af	42
3f635721 JB	43	movq %rbx, PER_CPU_VAR((%rsi))
3f635721 JB	44	movq %rcx, PER_CPU_VAR(8(%rsi))
b9ec40af	45
3f635721 JB	46	CFI_REMEMBER_STATE
3f635721 JB	47	popfq_cfi
b9ec40af CL	48	mov $1, %al
	49	ret
	50
3f635721 JB	51	CFI_RESTORE_STATE
	52	.Lnot_same:
	53	popfq_cfi
b9ec40af CL	54	xor %al,%al
	55	ret
	56
	57	CFI_ENDPROC
	58
	59	ENDPROC(this_cpu_cmpxchg16b_emu)