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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 | #ifdef __KERNEL__ #ifndef _PPC_SEMAPHORE_HELPER_H #define _PPC_SEMAPHORE_HELPER_H /* * SMP- and interrupt-safe semaphores.. * * (C) Copyright 1996 Linus Torvalds * Adapted for PowerPC by Gary Thomas and Paul Mackerras */ #include <asm/atomic.h> /* * These two (wake_one_more and waking_non_zero) _must_ execute * atomically wrt each other. * * This is trivially done with load with reservation and * store conditional on the ppc. */ static inline void wake_one_more(struct semaphore * sem) { atomic_inc(&sem->waking); } static inline int waking_non_zero(struct semaphore *sem) { int ret, tmp; /* Atomic decrement sem->waking iff it is > 0 */ __asm__ __volatile__( "1: lwarx %1,0,%2\n" /* tmp = sem->waking */ " cmpwi 0,%1,0\n" /* test tmp */ " addic %1,%1,-1\n" /* --tmp */ " ble- 2f\n" /* exit if tmp was <= 0 */ " stwcx. %1,0,%2\n" /* update sem->waking */ " bne- 1b\n" /* try again if update failed*/ " li %0,1\n" /* ret = 1 */ "2:" : "=r" (ret), "=&r" (tmp) : "r" (&sem->waking), "0" (0) : "cr0", "memory"); return ret; } /* * waking_non_zero_interruptible: * 1 got the lock * 0 go to sleep * -EINTR interrupted */ static inline int waking_non_zero_interruptible(struct semaphore *sem, struct task_struct *tsk) { int ret, tmp; /* Atomic decrement sem->waking iff it is > 0 */ __asm__ __volatile__( "1: lwarx %1,0,%2\n" /* tmp = sem->waking */ " cmpwi 0,%1,0\n" /* test tmp */ " addic %1,%1,-1\n" /* --tmp */ " ble- 2f\n" /* exit if tmp was <= 0 */ " stwcx. %1,0,%2\n" /* update sem->waking */ " bne- 1b\n" /* try again if update failed*/ " li %0,1\n" /* ret = 1 */ "2:" : "=r" (ret), "=&r" (tmp) : "r" (&sem->waking), "0" (0) : "cr0", "memory"); if (ret == 0 && signal_pending(tsk)) { atomic_inc(&sem->count); ret = -EINTR; } return ret; } /* * waking_non_zero_trylock: * 1 failed to lock * 0 got the lock */ static inline int waking_non_zero_trylock(struct semaphore *sem) { int ret, tmp; /* Atomic decrement sem->waking iff it is > 0 */ __asm__ __volatile__( "1: lwarx %1,0,%2\n" /* tmp = sem->waking */ " cmpwi 0,%1,0\n" /* test tmp */ " addic %1,%1,-1\n" /* --tmp */ " ble- 2f\n" /* exit if tmp was <= 0 */ " stwcx. %1,0,%2\n" /* update sem->waking */ " bne- 1b\n" /* try again if update failed*/ " li %0,0\n" /* ret = 0 */ "2:" : "=r" (ret), "=&r" (tmp) : "r" (&sem->waking), "0" (1) : "cr0", "memory"); if (ret) atomic_inc(&sem->count); return ret; } #endif /* _PPC_SEMAPHORE_HELPER_H */ #endif /* __KERNEL__ */ |