xref: /linux/arch/sh/include/asm/atomic-llsc.h (revision cbac924200b838cfb8d8b1415113d788089dc50b)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_SH_ATOMIC_LLSC_H
3 #define __ASM_SH_ATOMIC_LLSC_H
4 
5 /*
6  * SH-4A note:
7  *
8  * We basically get atomic_xxx_return() for free compared with
9  * atomic_xxx(). movli.l/movco.l require r0 due to the instruction
10  * encoding, so the retval is automatically set without having to
11  * do any special work.
12  */
13 /*
14  * To get proper branch prediction for the main line, we must branch
15  * forward to code at the end of this object's .text section, then
16  * branch back to restart the operation.
17  */
18 
19 #define ATOMIC_OP(op)							\
20 static inline void arch_atomic_##op(int i, atomic_t *v)			\
21 {									\
22 	unsigned long tmp;						\
23 									\
24 	__asm__ __volatile__ (						\
25 "1:	movli.l @%2, %0		! atomic_" #op "\n"			\
26 "	" #op "	%1, %0				\n"			\
27 "	movco.l	%0, @%2				\n"			\
28 "	bf	1b				\n"			\
29 	: "=&z" (tmp)							\
30 	: "r" (i), "r" (&v->counter)					\
31 	: "t");								\
32 }
33 
34 #define ATOMIC_OP_RETURN(op)						\
35 static inline int arch_atomic_##op##_return(int i, atomic_t *v)		\
36 {									\
37 	unsigned long temp;						\
38 									\
39 	__asm__ __volatile__ (						\
40 "1:	movli.l @%2, %0		! atomic_" #op "_return	\n"		\
41 "	" #op "	%1, %0					\n"		\
42 "	movco.l	%0, @%2					\n"		\
43 "	bf	1b					\n"		\
44 "	synco						\n"		\
45 	: "=&z" (temp)							\
46 	: "r" (i), "r" (&v->counter)					\
47 	: "t");								\
48 									\
49 	return temp;							\
50 }
51 
52 #define ATOMIC_FETCH_OP(op)						\
53 static inline int arch_atomic_fetch_##op(int i, atomic_t *v)		\
54 {									\
55 	unsigned long res, temp;					\
56 									\
57 	__asm__ __volatile__ (						\
58 "1:	movli.l @%3, %0		! atomic_fetch_" #op "	\n"		\
59 "	mov %0, %1					\n"		\
60 "	" #op "	%2, %0					\n"		\
61 "	movco.l	%0, @%3					\n"		\
62 "	bf	1b					\n"		\
63 "	synco						\n"		\
64 	: "=&z" (temp), "=&r" (res)					\
65 	: "r" (i), "r" (&v->counter)					\
66 	: "t");								\
67 									\
68 	return res;							\
69 }
70 
71 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
72 
73 ATOMIC_OPS(add)
74 ATOMIC_OPS(sub)
75 
76 #undef ATOMIC_OPS
77 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)
78 
79 ATOMIC_OPS(and)
80 ATOMIC_OPS(or)
81 ATOMIC_OPS(xor)
82 
83 #undef ATOMIC_OPS
84 #undef ATOMIC_FETCH_OP
85 #undef ATOMIC_OP_RETURN
86 #undef ATOMIC_OP
87 
88 #endif /* __ASM_SH_ATOMIC_LLSC_H */
89