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/arch/alpha/include/asm/xchg.h

https://bitbucket.org/thekraven/iscream_thunderc-2.6.35
C++ Header | 258 lines | 203 code | 31 blank | 24 comment | 2 complexity | 01f37cab54ced57bdcc278dcbd8a2466 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1#ifndef __ALPHA_SYSTEM_H
  2#error Do not include xchg.h directly!
  3#else
  4/*
  5 * xchg/xchg_local and cmpxchg/cmpxchg_local share the same code
  6 * except that local version do not have the expensive memory barrier.
  7 * So this file is included twice from asm/system.h.
  8 */
  9
 10/*
 11 * Atomic exchange.
 12 * Since it can be used to implement critical sections
 13 * it must clobber "memory" (also for interrupts in UP).
 14 */
 15
 16static inline unsigned long
 17____xchg(_u8, volatile char *m, unsigned long val)
 18{
 19	unsigned long ret, tmp, addr64;
 20
 21	__asm__ __volatile__(
 22	"	andnot	%4,7,%3\n"
 23	"	insbl	%1,%4,%1\n"
 24	"1:	ldq_l	%2,0(%3)\n"
 25	"	extbl	%2,%4,%0\n"
 26	"	mskbl	%2,%4,%2\n"
 27	"	or	%1,%2,%2\n"
 28	"	stq_c	%2,0(%3)\n"
 29	"	beq	%2,2f\n"
 30		__ASM__MB
 31	".subsection 2\n"
 32	"2:	br	1b\n"
 33	".previous"
 34	: "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
 35	: "r" ((long)m), "1" (val) : "memory");
 36
 37	return ret;
 38}
 39
 40static inline unsigned long
 41____xchg(_u16, volatile short *m, unsigned long val)
 42{
 43	unsigned long ret, tmp, addr64;
 44
 45	__asm__ __volatile__(
 46	"	andnot	%4,7,%3\n"
 47	"	inswl	%1,%4,%1\n"
 48	"1:	ldq_l	%2,0(%3)\n"
 49	"	extwl	%2,%4,%0\n"
 50	"	mskwl	%2,%4,%2\n"
 51	"	or	%1,%2,%2\n"
 52	"	stq_c	%2,0(%3)\n"
 53	"	beq	%2,2f\n"
 54		__ASM__MB
 55	".subsection 2\n"
 56	"2:	br	1b\n"
 57	".previous"
 58	: "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
 59	: "r" ((long)m), "1" (val) : "memory");
 60
 61	return ret;
 62}
 63
 64static inline unsigned long
 65____xchg(_u32, volatile int *m, unsigned long val)
 66{
 67	unsigned long dummy;
 68
 69	__asm__ __volatile__(
 70	"1:	ldl_l %0,%4\n"
 71	"	bis $31,%3,%1\n"
 72	"	stl_c %1,%2\n"
 73	"	beq %1,2f\n"
 74		__ASM__MB
 75	".subsection 2\n"
 76	"2:	br 1b\n"
 77	".previous"
 78	: "=&r" (val), "=&r" (dummy), "=m" (*m)
 79	: "rI" (val), "m" (*m) : "memory");
 80
 81	return val;
 82}
 83
 84static inline unsigned long
 85____xchg(_u64, volatile long *m, unsigned long val)
 86{
 87	unsigned long dummy;
 88
 89	__asm__ __volatile__(
 90	"1:	ldq_l %0,%4\n"
 91	"	bis $31,%3,%1\n"
 92	"	stq_c %1,%2\n"
 93	"	beq %1,2f\n"
 94		__ASM__MB
 95	".subsection 2\n"
 96	"2:	br 1b\n"
 97	".previous"
 98	: "=&r" (val), "=&r" (dummy), "=m" (*m)
 99	: "rI" (val), "m" (*m) : "memory");
100
101	return val;
102}
103
104/* This function doesn't exist, so you'll get a linker error
105   if something tries to do an invalid xchg().  */
106extern void __xchg_called_with_bad_pointer(void);
107
108static __always_inline unsigned long
109____xchg(, volatile void *ptr, unsigned long x, int size)
110{
111	switch (size) {
112		case 1:
113			return ____xchg(_u8, ptr, x);
114		case 2:
115			return ____xchg(_u16, ptr, x);
116		case 4:
117			return ____xchg(_u32, ptr, x);
118		case 8:
119			return ____xchg(_u64, ptr, x);
120	}
121	__xchg_called_with_bad_pointer();
122	return x;
123}
124
125/*
126 * Atomic compare and exchange.  Compare OLD with MEM, if identical,
127 * store NEW in MEM.  Return the initial value in MEM.  Success is
128 * indicated by comparing RETURN with OLD.
129 *
130 * The memory barrier should be placed in SMP only when we actually
131 * make the change. If we don't change anything (so if the returned
132 * prev is equal to old) then we aren't acquiring anything new and
133 * we don't need any memory barrier as far I can tell.
134 */
135
136static inline unsigned long
137____cmpxchg(_u8, volatile char *m, unsigned char old, unsigned char new)
138{
139	unsigned long prev, tmp, cmp, addr64;
140
141	__asm__ __volatile__(
142	"	andnot	%5,7,%4\n"
143	"	insbl	%1,%5,%1\n"
144	"1:	ldq_l	%2,0(%4)\n"
145	"	extbl	%2,%5,%0\n"
146	"	cmpeq	%0,%6,%3\n"
147	"	beq	%3,2f\n"
148	"	mskbl	%2,%5,%2\n"
149	"	or	%1,%2,%2\n"
150	"	stq_c	%2,0(%4)\n"
151	"	beq	%2,3f\n"
152		__ASM__MB
153	"2:\n"
154	".subsection 2\n"
155	"3:	br	1b\n"
156	".previous"
157	: "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
158	: "r" ((long)m), "Ir" (old), "1" (new) : "memory");
159
160	return prev;
161}
162
163static inline unsigned long
164____cmpxchg(_u16, volatile short *m, unsigned short old, unsigned short new)
165{
166	unsigned long prev, tmp, cmp, addr64;
167
168	__asm__ __volatile__(
169	"	andnot	%5,7,%4\n"
170	"	inswl	%1,%5,%1\n"
171	"1:	ldq_l	%2,0(%4)\n"
172	"	extwl	%2,%5,%0\n"
173	"	cmpeq	%0,%6,%3\n"
174	"	beq	%3,2f\n"
175	"	mskwl	%2,%5,%2\n"
176	"	or	%1,%2,%2\n"
177	"	stq_c	%2,0(%4)\n"
178	"	beq	%2,3f\n"
179		__ASM__MB
180	"2:\n"
181	".subsection 2\n"
182	"3:	br	1b\n"
183	".previous"
184	: "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
185	: "r" ((long)m), "Ir" (old), "1" (new) : "memory");
186
187	return prev;
188}
189
190static inline unsigned long
191____cmpxchg(_u32, volatile int *m, int old, int new)
192{
193	unsigned long prev, cmp;
194
195	__asm__ __volatile__(
196	"1:	ldl_l %0,%5\n"
197	"	cmpeq %0,%3,%1\n"
198	"	beq %1,2f\n"
199	"	mov %4,%1\n"
200	"	stl_c %1,%2\n"
201	"	beq %1,3f\n"
202		__ASM__MB
203	"2:\n"
204	".subsection 2\n"
205	"3:	br 1b\n"
206	".previous"
207	: "=&r"(prev), "=&r"(cmp), "=m"(*m)
208	: "r"((long) old), "r"(new), "m"(*m) : "memory");
209
210	return prev;
211}
212
213static inline unsigned long
214____cmpxchg(_u64, volatile long *m, unsigned long old, unsigned long new)
215{
216	unsigned long prev, cmp;
217
218	__asm__ __volatile__(
219	"1:	ldq_l %0,%5\n"
220	"	cmpeq %0,%3,%1\n"
221	"	beq %1,2f\n"
222	"	mov %4,%1\n"
223	"	stq_c %1,%2\n"
224	"	beq %1,3f\n"
225		__ASM__MB
226	"2:\n"
227	".subsection 2\n"
228	"3:	br 1b\n"
229	".previous"
230	: "=&r"(prev), "=&r"(cmp), "=m"(*m)
231	: "r"((long) old), "r"(new), "m"(*m) : "memory");
232
233	return prev;
234}
235
236/* This function doesn't exist, so you'll get a linker error
237   if something tries to do an invalid cmpxchg().  */
238extern void __cmpxchg_called_with_bad_pointer(void);
239
240static __always_inline unsigned long
241____cmpxchg(, volatile void *ptr, unsigned long old, unsigned long new,
242	      int size)
243{
244	switch (size) {
245		case 1:
246			return ____cmpxchg(_u8, ptr, old, new);
247		case 2:
248			return ____cmpxchg(_u16, ptr, old, new);
249		case 4:
250			return ____cmpxchg(_u32, ptr, old, new);
251		case 8:
252			return ____cmpxchg(_u64, ptr, old, new);
253	}
254	__cmpxchg_called_with_bad_pointer();
255	return old;
256}
257
258#endif