Commit | Line | Data |
---|---|---|
2acbb8c6 | 1 | /* |
ae564c63 NP |
2 | * Optimised mutex implementation of include/asm-generic/mutex-dec.h algorithm |
3 | */ | |
4 | #ifndef _ASM_POWERPC_MUTEX_H | |
5 | #define _ASM_POWERPC_MUTEX_H | |
6 | ||
7 | static inline int __mutex_cmpxchg_lock(atomic_t *v, int old, int new) | |
8 | { | |
9 | int t; | |
10 | ||
11 | __asm__ __volatile__ ( | |
12 | "1: lwarx %0,0,%1 # mutex trylock\n\ | |
13 | cmpw 0,%0,%2\n\ | |
14 | bne- 2f\n" | |
15 | PPC405_ERR77(0,%1) | |
16 | " stwcx. %3,0,%1\n\ | |
17 | bne- 1b" | |
f10e2e5b | 18 | PPC_ACQUIRE_BARRIER |
ae564c63 NP |
19 | "\n\ |
20 | 2:" | |
21 | : "=&r" (t) | |
22 | : "r" (&v->counter), "r" (old), "r" (new) | |
23 | : "cc", "memory"); | |
24 | ||
25 | return t; | |
26 | } | |
27 | ||
28 | static inline int __mutex_dec_return_lock(atomic_t *v) | |
29 | { | |
30 | int t; | |
31 | ||
32 | __asm__ __volatile__( | |
33 | "1: lwarx %0,0,%1 # mutex lock\n\ | |
34 | addic %0,%0,-1\n" | |
35 | PPC405_ERR77(0,%1) | |
36 | " stwcx. %0,0,%1\n\ | |
37 | bne- 1b" | |
f10e2e5b | 38 | PPC_ACQUIRE_BARRIER |
ae564c63 NP |
39 | : "=&r" (t) |
40 | : "r" (&v->counter) | |
41 | : "cc", "memory"); | |
42 | ||
43 | return t; | |
44 | } | |
45 | ||
46 | static inline int __mutex_inc_return_unlock(atomic_t *v) | |
47 | { | |
48 | int t; | |
49 | ||
50 | __asm__ __volatile__( | |
f10e2e5b | 51 | PPC_RELEASE_BARRIER |
ae564c63 NP |
52 | "1: lwarx %0,0,%1 # mutex unlock\n\ |
53 | addic %0,%0,1\n" | |
54 | PPC405_ERR77(0,%1) | |
55 | " stwcx. %0,0,%1 \n\ | |
56 | bne- 1b" | |
57 | : "=&r" (t) | |
58 | : "r" (&v->counter) | |
59 | : "cc", "memory"); | |
60 | ||
61 | return t; | |
62 | } | |
63 | ||
64 | /** | |
65 | * __mutex_fastpath_lock - try to take the lock by moving the count | |
66 | * from 1 to a 0 value | |
67 | * @count: pointer of type atomic_t | |
68 | * @fail_fn: function to call if the original value was not 1 | |
69 | * | |
70 | * Change the count from 1 to a value lower than 1, and call <fail_fn> if | |
71 | * it wasn't 1 originally. This function MUST leave the value lower than | |
72 | * 1 even when the "1" assertion wasn't true. | |
73 | */ | |
74 | static inline void | |
75 | __mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *)) | |
76 | { | |
77 | if (unlikely(__mutex_dec_return_lock(count) < 0)) | |
78 | fail_fn(count); | |
79 | } | |
80 | ||
81 | /** | |
82 | * __mutex_fastpath_lock_retval - try to take the lock by moving the count | |
83 | * from 1 to a 0 value | |
84 | * @count: pointer of type atomic_t | |
ae564c63 | 85 | * |
a41b56ef ML |
86 | * Change the count from 1 to a value lower than 1. This function returns 0 |
87 | * if the fastpath succeeds, or -1 otherwise. | |
ae564c63 NP |
88 | */ |
89 | static inline int | |
a41b56ef | 90 | __mutex_fastpath_lock_retval(atomic_t *count) |
ae564c63 NP |
91 | { |
92 | if (unlikely(__mutex_dec_return_lock(count) < 0)) | |
a41b56ef | 93 | return -1; |
ae564c63 NP |
94 | return 0; |
95 | } | |
96 | ||
97 | /** | |
98 | * __mutex_fastpath_unlock - try to promote the count from 0 to 1 | |
99 | * @count: pointer of type atomic_t | |
100 | * @fail_fn: function to call if the original value was not 0 | |
101 | * | |
102 | * Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>. | |
103 | * In the failure case, this function is allowed to either set the value to | |
104 | * 1, or to set it to a value lower than 1. | |
105 | */ | |
106 | static inline void | |
107 | __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *)) | |
108 | { | |
109 | if (unlikely(__mutex_inc_return_unlock(count) <= 0)) | |
110 | fail_fn(count); | |
111 | } | |
112 | ||
113 | #define __mutex_slowpath_needs_to_unlock() 1 | |
114 | ||
115 | /** | |
116 | * __mutex_fastpath_trylock - try to acquire the mutex, without waiting | |
117 | * | |
118 | * @count: pointer of type atomic_t | |
119 | * @fail_fn: fallback function | |
2acbb8c6 | 120 | * |
ae564c63 NP |
121 | * Change the count from 1 to 0, and return 1 (success), or if the count |
122 | * was not 1, then return 0 (failure). | |
2acbb8c6 | 123 | */ |
ae564c63 NP |
124 | static inline int |
125 | __mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *)) | |
126 | { | |
6428671b | 127 | if (likely(atomic_read(count) == 1 && __mutex_cmpxchg_lock(count, 1, 0) == 1)) |
ae564c63 NP |
128 | return 1; |
129 | return 0; | |
130 | } | |
2acbb8c6 | 131 | |
ae564c63 | 132 | #endif |