atomic64_cx8_32.S

  1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2/*
  3 * atomic64_t for 586+
  4 *
  5 * Copyright © 2010  Luca Barbieri
  6 */
  7
  8#include <linux/linkage.h>
  9#include <asm/alternative.h>
 10
 11.macro read64 reg
 12	movl %ebx, %eax
 13	movl %ecx, %edx
 14/* we need LOCK_PREFIX since otherwise cmpxchg8b always does the write */
 15	LOCK_PREFIX
 16	cmpxchg8b (\reg)
 17.endm
 18
 19.macro read64_nonatomic reg
 20	movl (\reg), %eax
 21	movl 4(\reg), %edx
 22.endm
 23
 24SYM_FUNC_START(atomic64_read_cx8)
 25	read64 %ecx
 26	RET
 27SYM_FUNC_END(atomic64_read_cx8)
 28
 29SYM_FUNC_START(atomic64_set_cx8)
 301:
 31/* we don't need LOCK_PREFIX since aligned 64-bit writes
 32 * are atomic on 586 and newer */
 33	cmpxchg8b (%esi)
 34	jne 1b
 35
 36	RET
 37SYM_FUNC_END(atomic64_set_cx8)
 38
 39SYM_FUNC_START(atomic64_xchg_cx8)
 401:
 41	LOCK_PREFIX
 42	cmpxchg8b (%esi)
 43	jne 1b
 44
 45	RET
 46SYM_FUNC_END(atomic64_xchg_cx8)
 47
 48.macro addsub_return func ins insc
 49SYM_FUNC_START(atomic64_\func\()_return_cx8)
 50	pushl %ebp
 51	pushl %ebx
 52	pushl %esi
 53	pushl %edi
 54
 55	movl %eax, %esi
 56	movl %edx, %edi
 57	movl %ecx, %ebp
 58
 59	read64_nonatomic %ecx
 601:
 61	movl %eax, %ebx
 62	movl %edx, %ecx
 63	\ins\()l %esi, %ebx
 64	\insc\()l %edi, %ecx
 65	LOCK_PREFIX
 66	cmpxchg8b (%ebp)
 67	jne 1b
 68
 6910:
 70	movl %ebx, %eax
 71	movl %ecx, %edx
 72	popl %edi
 73	popl %esi
 74	popl %ebx
 75	popl %ebp
 76	RET
 77SYM_FUNC_END(atomic64_\func\()_return_cx8)
 78.endm
 79
 80addsub_return add add adc
 81addsub_return sub sub sbb
 82
 83.macro incdec_return func ins insc
 84SYM_FUNC_START(atomic64_\func\()_return_cx8)
 85	pushl %ebx
 86
 87	read64_nonatomic %esi
 881:
 89	movl %eax, %ebx
 90	movl %edx, %ecx
 91	\ins\()l $1, %ebx
 92	\insc\()l $0, %ecx
 93	LOCK_PREFIX
 94	cmpxchg8b (%esi)
 95	jne 1b
 96
 9710:
 98	movl %ebx, %eax
 99	movl %ecx, %edx
100	popl %ebx
101	RET
102SYM_FUNC_END(atomic64_\func\()_return_cx8)
103.endm
104
105incdec_return inc add adc
106incdec_return dec sub sbb
107
108SYM_FUNC_START(atomic64_dec_if_positive_cx8)
109	pushl %ebx
110
111	read64 %esi
1121:
113	movl %eax, %ebx
114	movl %edx, %ecx
115	subl $1, %ebx
116	sbb $0, %ecx
117	js 2f
118	LOCK_PREFIX
119	cmpxchg8b (%esi)
120	jne 1b
121
1222:
123	movl %ebx, %eax
124	movl %ecx, %edx
125	popl %ebx
126	RET
127SYM_FUNC_END(atomic64_dec_if_positive_cx8)
128
129SYM_FUNC_START(atomic64_add_unless_cx8)
130	pushl %ebp
131	pushl %ebx
132/* these just push these two parameters on the stack */
133	pushl %edi
134	pushl %ecx
135
136	movl %eax, %ebp
137	movl %edx, %edi
138
139	read64 %esi
1401:
141	cmpl %eax, 0(%esp)
142	je 4f
1432:
144	movl %eax, %ebx
145	movl %edx, %ecx
146	addl %ebp, %ebx
147	adcl %edi, %ecx
148	LOCK_PREFIX
149	cmpxchg8b (%esi)
150	jne 1b
151
152	movl $1, %eax
1533:
154	addl $8, %esp
155	popl %ebx
156	popl %ebp
157	RET
1584:
159	cmpl %edx, 4(%esp)
160	jne 2b
161	xorl %eax, %eax
162	jmp 3b
163SYM_FUNC_END(atomic64_add_unless_cx8)
164
165SYM_FUNC_START(atomic64_inc_not_zero_cx8)
166	pushl %ebx
167
168	read64 %esi
1691:
170	movl %eax, %ecx
171	orl %edx, %ecx
172	jz 3f
173	movl %eax, %ebx
174	xorl %ecx, %ecx
175	addl $1, %ebx
176	adcl %edx, %ecx
177	LOCK_PREFIX
178	cmpxchg8b (%esi)
179	jne 1b
180
181	movl $1, %eax
1823:
183	popl %ebx
184	RET
185SYM_FUNC_END(atomic64_inc_not_zero_cx8)