Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Locks for smp ppc | |
3 | * | |
4 | * Written by Cort Dougan (cort@cs.nmt.edu) | |
5 | */ | |
6 | ||
1da177e4 LT |
7 | #include <linux/sched.h> |
8 | #include <linux/spinlock.h> | |
9 | #include <linux/module.h> | |
10 | #include <asm/ppc_asm.h> | |
11 | #include <asm/smp.h> | |
12 | ||
13 | #ifdef CONFIG_DEBUG_SPINLOCK | |
14 | ||
15 | #undef INIT_STUCK | |
16 | #define INIT_STUCK 200000000 /*0xffffffff*/ | |
17 | ||
18 | /* | |
19 | * Try to acquire a spinlock. | |
20 | * Only does the stwcx. if the load returned 0 - the Programming | |
21 | * Environments Manual suggests not doing unnecessary stcwx.'s | |
22 | * since they may inhibit forward progress by other CPUs in getting | |
23 | * a lock. | |
24 | */ | |
25 | static inline unsigned long __spin_trylock(volatile unsigned long *lock) | |
26 | { | |
27 | unsigned long ret; | |
28 | ||
29 | __asm__ __volatile__ ("\n\ | |
30 | 1: lwarx %0,0,%1\n\ | |
31 | cmpwi 0,%0,0\n\ | |
32 | bne 2f\n" | |
33 | PPC405_ERR77(0,%1) | |
34 | " stwcx. %2,0,%1\n\ | |
35 | bne- 1b\n\ | |
36 | isync\n\ | |
37 | 2:" | |
38 | : "=&r"(ret) | |
39 | : "r"(lock), "r"(1) | |
40 | : "cr0", "memory"); | |
41 | ||
42 | return ret; | |
43 | } | |
44 | ||
45 | void _raw_spin_lock(spinlock_t *lock) | |
46 | { | |
47 | int cpu = smp_processor_id(); | |
48 | unsigned int stuck = INIT_STUCK; | |
49 | while (__spin_trylock(&lock->lock)) { | |
50 | while ((unsigned volatile long)lock->lock != 0) { | |
51 | if (!--stuck) { | |
52 | printk("_spin_lock(%p) CPU#%d NIP %p" | |
53 | " holder: cpu %ld pc %08lX\n", | |
54 | lock, cpu, __builtin_return_address(0), | |
55 | lock->owner_cpu,lock->owner_pc); | |
56 | stuck = INIT_STUCK; | |
57 | /* steal the lock */ | |
58 | /*xchg_u32((void *)&lock->lock,0);*/ | |
59 | } | |
60 | } | |
61 | } | |
62 | lock->owner_pc = (unsigned long)__builtin_return_address(0); | |
63 | lock->owner_cpu = cpu; | |
64 | } | |
65 | EXPORT_SYMBOL(_raw_spin_lock); | |
66 | ||
67 | int _raw_spin_trylock(spinlock_t *lock) | |
68 | { | |
69 | if (__spin_trylock(&lock->lock)) | |
70 | return 0; | |
71 | lock->owner_cpu = smp_processor_id(); | |
72 | lock->owner_pc = (unsigned long)__builtin_return_address(0); | |
73 | return 1; | |
74 | } | |
75 | EXPORT_SYMBOL(_raw_spin_trylock); | |
76 | ||
77 | void _raw_spin_unlock(spinlock_t *lp) | |
78 | { | |
79 | if ( !lp->lock ) | |
80 | printk("_spin_unlock(%p): no lock cpu %d curr PC %p %s/%d\n", | |
81 | lp, smp_processor_id(), __builtin_return_address(0), | |
82 | current->comm, current->pid); | |
83 | if ( lp->owner_cpu != smp_processor_id() ) | |
84 | printk("_spin_unlock(%p): cpu %d trying clear of cpu %d pc %lx val %lx\n", | |
85 | lp, smp_processor_id(), (int)lp->owner_cpu, | |
86 | lp->owner_pc,lp->lock); | |
87 | lp->owner_pc = lp->owner_cpu = 0; | |
88 | wmb(); | |
89 | lp->lock = 0; | |
90 | } | |
91 | EXPORT_SYMBOL(_raw_spin_unlock); | |
92 | ||
93 | /* | |
94 | * For rwlocks, zero is unlocked, -1 is write-locked, | |
95 | * positive is read-locked. | |
96 | */ | |
97 | static __inline__ int __read_trylock(rwlock_t *rw) | |
98 | { | |
99 | signed int tmp; | |
100 | ||
101 | __asm__ __volatile__( | |
102 | "2: lwarx %0,0,%1 # __read_trylock\n\ | |
103 | addic. %0,%0,1\n\ | |
104 | ble- 1f\n" | |
105 | PPC405_ERR77(0,%1) | |
106 | " stwcx. %0,0,%1\n\ | |
107 | bne- 2b\n\ | |
108 | isync\n\ | |
109 | 1:" | |
110 | : "=&r"(tmp) | |
111 | : "r"(&rw->lock) | |
112 | : "cr0", "memory"); | |
113 | ||
114 | return tmp; | |
115 | } | |
116 | ||
117 | int _raw_read_trylock(rwlock_t *rw) | |
118 | { | |
119 | return __read_trylock(rw) > 0; | |
120 | } | |
121 | EXPORT_SYMBOL(_raw_read_trylock); | |
122 | ||
123 | void _raw_read_lock(rwlock_t *rw) | |
124 | { | |
125 | unsigned int stuck; | |
126 | ||
127 | while (__read_trylock(rw) <= 0) { | |
128 | stuck = INIT_STUCK; | |
129 | while (!read_can_lock(rw)) { | |
130 | if (--stuck == 0) { | |
131 | printk("_read_lock(%p) CPU#%d lock %d\n", | |
39c715b7 | 132 | rw, raw_smp_processor_id(), rw->lock); |
1da177e4 LT |
133 | stuck = INIT_STUCK; |
134 | } | |
135 | } | |
136 | } | |
137 | } | |
138 | EXPORT_SYMBOL(_raw_read_lock); | |
139 | ||
140 | void _raw_read_unlock(rwlock_t *rw) | |
141 | { | |
142 | if ( rw->lock == 0 ) | |
143 | printk("_read_unlock(): %s/%d (nip %08lX) lock %d\n", | |
144 | current->comm,current->pid,current->thread.regs->nip, | |
145 | rw->lock); | |
146 | wmb(); | |
147 | atomic_dec((atomic_t *) &(rw)->lock); | |
148 | } | |
149 | EXPORT_SYMBOL(_raw_read_unlock); | |
150 | ||
151 | void _raw_write_lock(rwlock_t *rw) | |
152 | { | |
153 | unsigned int stuck; | |
154 | ||
155 | while (cmpxchg(&rw->lock, 0, -1) != 0) { | |
156 | stuck = INIT_STUCK; | |
157 | while (!write_can_lock(rw)) { | |
158 | if (--stuck == 0) { | |
159 | printk("write_lock(%p) CPU#%d lock %d)\n", | |
39c715b7 | 160 | rw, raw_smp_processor_id(), rw->lock); |
1da177e4 LT |
161 | stuck = INIT_STUCK; |
162 | } | |
163 | } | |
164 | } | |
165 | wmb(); | |
166 | } | |
167 | EXPORT_SYMBOL(_raw_write_lock); | |
168 | ||
169 | int _raw_write_trylock(rwlock_t *rw) | |
170 | { | |
171 | if (cmpxchg(&rw->lock, 0, -1) != 0) | |
172 | return 0; | |
173 | wmb(); | |
174 | return 1; | |
175 | } | |
176 | EXPORT_SYMBOL(_raw_write_trylock); | |
177 | ||
178 | void _raw_write_unlock(rwlock_t *rw) | |
179 | { | |
180 | if (rw->lock >= 0) | |
181 | printk("_write_lock(): %s/%d (nip %08lX) lock %d\n", | |
182 | current->comm,current->pid,current->thread.regs->nip, | |
183 | rw->lock); | |
184 | wmb(); | |
185 | rw->lock = 0; | |
186 | } | |
187 | EXPORT_SYMBOL(_raw_write_unlock); | |
188 | ||
189 | #endif |