/*
* atomic64_t for 586+
*
* Copyright © 2010 Luca Barbieri
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/linkage.h>
#include <asm/alternative-asm.h>
#include <asm/dwarf2.h>
.macro SAVE reg
pushl_cfi %\reg
CFI_REL_OFFSET \reg, 0
.endm
.macro RESTORE reg
popl_cfi %\reg
CFI_RESTORE \reg
.endm
.macro read64 reg
movl %ebx, %eax
movl %ecx, %edx
/* we need LOCK_PREFIX since otherwise cmpxchg8b always does the write */
LOCK_PREFIX
cmpxchg8b (\reg)
.endm
ENTRY(atomic64_read_cx8)
CFI_STARTPROC
read64 %ecx
ret
CFI_ENDPROC
ENDPROC(atomic64_read_cx8)
ENTRY(atomic64_set_cx8)
CFI_STARTPROC
1:
/* we don't need LOCK_PREFIX since aligned 64-bit writes
* are atomic on 586 and newer */
cmpxchg8b (%esi)
jne 1b
ret
CFI_ENDPROC
ENDPROC(atomic64_set_cx8)
ENTRY(atomic64_xchg_cx8)
CFI_STARTPROC
1:
LOCK_PREFIX
cmpxchg8b (%esi)
jne 1b
ret
CFI_ENDPROC
ENDPROC(atomic64_xchg_cx8)
.macro addsub_return func ins insc
ENTRY(atomic64_\func\()_return_cx8)
CFI_STARTPROC
SAVE ebp
SAVE ebx
SAVE esi
SAVE edi
movl %eax, %esi
movl %edx, %edi
movl %ecx, %ebp
read64 %ecx
1:
movl %eax, %ebx
movl %edx, %ecx
\ins\()l %esi, %ebx
\insc\()l %edi, %ecx
LOCK_PREFIX
cmpxchg8b (%ebp)
jne 1b
10:
movl %ebx, %eax
movl %ecx, %edx
RESTORE edi
RESTORE esi
RESTORE ebx
RESTORE ebp
ret
CFI_ENDPROC
ENDPROC(atomic64_\func\()_return_cx8)
.endm
addsub_return add add adc
addsub_return sub sub sbb
.macro incdec_return func ins insc
ENTRY(atomic64_\func\()_return_cx8)
CFI_STARTPROC
SAVE ebx
read64 %esi
1:
movl %eax, %ebx
movl %edx, %ecx
\ins\()l $1, %ebx
\insc\()l $0, %ecx
LOCK_PREFIX
cmpxchg8b (%esi)
jne 1b
10:
movl %ebx, %eax
movl %ecx, %edx
RESTORE ebx
ret
CFI_ENDPROC
ENDPROC(atomic64_\func\()_return_cx8)
.endm
incdec_return inc add adc
incdec_return dec sub sbb
ENTRY(atomic64_dec_if_positive_cx8)
CFI_STARTPROC
SAVE ebx
read64 %esi
1:
movl %eax, %ebx
movl %edx, %ecx
subl $1, %ebx
sbb $0, %ecx
js 2f
LOCK_PREFIX
cmpxchg8b (%esi)
jne 1b
2:
movl %ebx, %eax
movl %ecx, %edx
RESTORE ebx
ret
CFI_ENDPROC
ENDPROC(atomic64_dec_if_positive_cx8)
ENTRY(atomic64_add_unless_cx8)
CFI_STARTPROC
SAVE ebp
SAVE ebx
/* these just push these two parameters on the stack */
SAVE edi
SAVE ecx
movl %eax, %ebp
movl %edx, %edi
read64 %esi
1:
cmpl %eax, 0(%esp)
je 4f
2:
movl %eax, %ebx
movl %edx, %ecx
addl %ebp, %ebx
adcl %edi, %ecx
LOCK_PREFIX
cmpxchg8b (%esi)
jne 1b
movl $1, %eax
3:
addl $8, %esp
CFI_ADJUST_CFA_OFFSET -8
RESTORE ebx
RESTORE ebp
ret
4:
cmpl %edx, 4(%esp)
jne 2b
xorl %eax, %eax
jmp 3b
CFI_ENDPROC
ENDPROC(atomic64_add_unless_cx8)
ENTRY(atomic64_inc_not_zero_cx8)
CFI_STARTPROC
SAVE ebx
read64 %esi
1:
movl %eax, %ecx
orl %edx, %ecx
jz 3f
movl %eax, %ebx
xorl %ecx, %ecx
addl $1, %ebx
adcl %edx, %ecx
LOCK_PREFIX
cmpxchg8b (%esi)
jne 1b
movl $1, %eax
3:
RESTORE ebx
ret
CFI_ENDPROC
ENDPROC(atomic64_inc_not_zero_cx8)
