atomic64-arcv2.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2
  3/*
  4 * ARCv2 supports 64-bit exclusive load (LLOCKD) / store (SCONDD)
  5 *  - The address HAS to be 64-bit aligned
  6 */
  7
  8#ifndef _ASM_ARC_ATOMIC64_ARCV2_H
  9#define _ASM_ARC_ATOMIC64_ARCV2_H
 10
 11typedef struct {
 12	s64 __aligned(8) counter;
 13} atomic64_t;
 14
 15#define ATOMIC64_INIT(a) { (a) }
 16
 17static inline s64 arch_atomic64_read(const atomic64_t *v)
 18{
 19	s64 val;
 20
 21	__asm__ __volatile__(
 22	"	ldd   %0, [%1]	\n"
 23	: "=r"(val)
 24	: "r"(&v->counter));
 25
 26	return val;
 27}
 28
 29static inline void arch_atomic64_set(atomic64_t *v, s64 a)
 30{
 31	/*
 32	 * This could have been a simple assignment in "C" but would need
 33	 * explicit volatile. Otherwise gcc optimizers could elide the store
 34	 * which borked atomic64 self-test
 35	 * In the inline asm version, memory clobber needed for exact same
 36	 * reason, to tell gcc about the store.
 37	 *
 38	 * This however is not needed for sibling atomic64_add() etc since both
 39	 * load/store are explicitly done in inline asm. As long as API is used
 40	 * for each access, gcc has no way to optimize away any load/store
 41	 */
 42	__asm__ __volatile__(
 43	"	std   %0, [%1]	\n"
 44	:
 45	: "r"(a), "r"(&v->counter)
 46	: "memory");
 47}
 48
 49#define ATOMIC64_OP(op, op1, op2)					\
 50static inline void arch_atomic64_##op(s64 a, atomic64_t *v)		\
 51{									\
 52	s64 val;							\
 53									\
 54	__asm__ __volatile__(						\
 55	"1:				\n"				\
 56	"	llockd  %0, [%1]	\n"				\
 57	"	" #op1 " %L0, %L0, %L2	\n"				\
 58	"	" #op2 " %H0, %H0, %H2	\n"				\
 59	"	scondd   %0, [%1]	\n"				\
 60	"	bnz     1b		\n"				\
 61	: "=&r"(val)							\
 62	: "r"(&v->counter), "ir"(a)					\
 63	: "cc", "memory");						\
 64}									\
 65
 66#define ATOMIC64_OP_RETURN(op, op1, op2)		        	\
 67static inline s64 arch_atomic64_##op##_return_relaxed(s64 a, atomic64_t *v)	\
 68{									\
 69	s64 val;							\
 70									\
 71	__asm__ __volatile__(						\
 72	"1:				\n"				\
 73	"	llockd   %0, [%1]	\n"				\
 74	"	" #op1 " %L0, %L0, %L2	\n"				\
 75	"	" #op2 " %H0, %H0, %H2	\n"				\
 76	"	scondd   %0, [%1]	\n"				\
 77	"	bnz     1b		\n"				\
 78	: [val] "=&r"(val)						\
 79	: "r"(&v->counter), "ir"(a)					\
 80	: "cc", "memory");						\
 81									\
 82	return val;							\
 83}
 84
 85#define arch_atomic64_add_return_relaxed	arch_atomic64_add_return_relaxed
 86#define arch_atomic64_sub_return_relaxed	arch_atomic64_sub_return_relaxed
 87
 88#define ATOMIC64_FETCH_OP(op, op1, op2)		        		\
 89static inline s64 arch_atomic64_fetch_##op##_relaxed(s64 a, atomic64_t *v)	\
 90{									\
 91	s64 val, orig;							\
 92									\
 93	__asm__ __volatile__(						\
 94	"1:				\n"				\
 95	"	llockd   %0, [%2]	\n"				\
 96	"	" #op1 " %L1, %L0, %L3	\n"				\
 97	"	" #op2 " %H1, %H0, %H3	\n"				\
 98	"	scondd   %1, [%2]	\n"				\
 99	"	bnz     1b		\n"				\
100	: "=&r"(orig), "=&r"(val)					\
101	: "r"(&v->counter), "ir"(a)					\
102	: "cc", "memory");						\
103									\
104	return orig;							\
105}
106
107#define arch_atomic64_fetch_add_relaxed		arch_atomic64_fetch_add_relaxed
108#define arch_atomic64_fetch_sub_relaxed		arch_atomic64_fetch_sub_relaxed
109
110#define arch_atomic64_fetch_and_relaxed		arch_atomic64_fetch_and_relaxed
111#define arch_atomic64_fetch_andnot_relaxed	arch_atomic64_fetch_andnot_relaxed
112#define arch_atomic64_fetch_or_relaxed		arch_atomic64_fetch_or_relaxed
113#define arch_atomic64_fetch_xor_relaxed		arch_atomic64_fetch_xor_relaxed
114
115#define ATOMIC64_OPS(op, op1, op2)					\
116	ATOMIC64_OP(op, op1, op2)					\
117	ATOMIC64_OP_RETURN(op, op1, op2)				\
118	ATOMIC64_FETCH_OP(op, op1, op2)
119
120ATOMIC64_OPS(add, add.f, adc)
121ATOMIC64_OPS(sub, sub.f, sbc)
122
123#undef ATOMIC64_OPS
124#define ATOMIC64_OPS(op, op1, op2)					\
125	ATOMIC64_OP(op, op1, op2)					\
126	ATOMIC64_FETCH_OP(op, op1, op2)
127
128ATOMIC64_OPS(and, and, and)
129ATOMIC64_OPS(andnot, bic, bic)
130ATOMIC64_OPS(or, or, or)
131ATOMIC64_OPS(xor, xor, xor)
132
133#define arch_atomic64_andnot		arch_atomic64_andnot
134
135#undef ATOMIC64_OPS
136#undef ATOMIC64_FETCH_OP
137#undef ATOMIC64_OP_RETURN
138#undef ATOMIC64_OP
139
140static inline u64 __arch_cmpxchg64_relaxed(volatile void *ptr, u64 old, u64 new)
141{
142	u64 prev;
143
144	__asm__ __volatile__(
145	"1:	llockd  %0, [%1]	\n"
146	"	brne    %L0, %L2, 2f	\n"
147	"	brne    %H0, %H2, 2f	\n"
148	"	scondd  %3, [%1]	\n"
149	"	bnz     1b		\n"
150	"2:				\n"
151	: "=&r"(prev)
152	: "r"(ptr), "ir"(old), "r"(new)
153	: "memory", "cc");
154
155	return prev;
156}
157#define arch_cmpxchg64_relaxed __arch_cmpxchg64_relaxed
158
159static inline s64 arch_atomic64_xchg(atomic64_t *ptr, s64 new)
160{
161	s64 prev;
162
163	smp_mb();
164
165	__asm__ __volatile__(
166	"1:	llockd  %0, [%1]	\n"
167	"	scondd  %2, [%1]	\n"
168	"	bnz     1b		\n"
169	"2:				\n"
170	: "=&r"(prev)
171	: "r"(ptr), "r"(new)
172	: "cc");	/* memory clobber comes from smp_mb() */
173
174	smp_mb();
175
176	return prev;
177}
178#define arch_atomic64_xchg arch_atomic64_xchg
179
180static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
181{
182	s64 val;
183
184	smp_mb();
185
186	__asm__ __volatile__(
187	"1:	llockd  %0, [%1]	\n"
188	"	sub.f   %L0, %L0, 1	# w0 - 1, set C on borrow\n"
189	"	sub.c   %H0, %H0, 1	# if C set, w1 - 1\n"
190	"	brlt    %H0, 0, 2f	\n"
191	"	scondd  %0, [%1]	\n"
192	"	bnz     1b		\n"
193	"2:				\n"
194	: "=&r"(val)
195	: "r"(&v->counter)
196	: "cc");	/* memory clobber comes from smp_mb() */
197
198	smp_mb();
199
200	return val;
201}
202#define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive
203
204static inline s64 arch_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
205{
206	s64 old, temp;
207
208	smp_mb();
209
210	__asm__ __volatile__(
211	"1:	llockd  %0, [%2]	\n"
212	"	brne	%L0, %L4, 2f	# continue to add since v != u \n"
213	"	breq.d	%H0, %H4, 3f	# return since v == u \n"
214	"2:				\n"
215	"	add.f   %L1, %L0, %L3	\n"
216	"	adc     %H1, %H0, %H3	\n"
217	"	scondd  %1, [%2]	\n"
218	"	bnz     1b		\n"
219	"3:				\n"
220	: "=&r"(old), "=&r" (temp)
221	: "r"(&v->counter), "r"(a), "r"(u)
222	: "cc");	/* memory clobber comes from smp_mb() */
223
224	smp_mb();
225
226	return old;
227}
228#define arch_atomic64_fetch_add_unless arch_atomic64_fetch_add_unless
229
230#endif