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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | /* * linux/include/asm-arm/semaphore.h */ #ifndef __ASM_PROC_SEMAPHORE_H #define __ASM_PROC_SEMAPHORE_H /* * This is ugly, but we want the default case to fall through. * "__down" is the actual routine that waits... */ extern inline void down(struct semaphore * sem) { unsigned int cpsr, temp; __asm__ __volatile__ (" @ atomic down operation mrs %0, cpsr orr %1, %0, #128 @ disable IRQs msr cpsr, %1 ldr %1, [%2] bic %0, %0, #0x80000000 @ clear N subs %1, %1, #1 str %1, [%2] orrmi %0, %0, #0x80000000 @ set N msr cpsr, %0 movmi r0, %2 blmi " SYMBOL_NAME_STR(__down_failed) : "=&r" (cpsr), "=&r" (temp) : "r" (sem) : "r0", "lr", "cc"); } /* * This is ugly, but we want the default case to fall through. * "__down_interruptible" is the actual routine that waits... */ extern inline int down_interruptible (struct semaphore * sem) { unsigned int cpsr, temp; __asm__ __volatile__ (" @ atomic down interruptible operation mrs %0, cpsr orr %1, %0, #128 @ disable IRQs msr cpsr, %1 ldr %1, [%2] bic %0, %0, #0x80000000 @ clear N subs %1, %1, #1 str %1, [%2] orrmi %0, %0, #0x80000000 @ set N msr cpsr, %0 movmi r0, %2 movpl r0, #0 blmi " SYMBOL_NAME_STR(__down_interruptible_failed) " mov %1, r0" : "=&r" (cpsr), "=&r" (temp) : "r" (sem) : "r0", "lr", "cc"); return temp; } extern inline int down_trylock(struct semaphore *sem) { unsigned int cpsr, temp; __asm__ __volatile__ (" @ atomic down try lock operation mrs %0, cpsr orr %1, %0, #128 @ disable IRQs msr cpsr, %1 ldr %1, [%2] bic %0, %0, #0x80000000 @ clear N subs %1, %1, #1 str %1, [%2] orrmi %0, %0, #0x80000000 @ set N msr cpsr, %0 movmi r0, %2 movpl r0, #0 blmi " SYMBOL_NAME_STR(__down_trylock_failed) " mov %1, r0" : "=&r" (cpsr), "=&r" (temp) : "r" (sem) : "r0", "lr", "cc"); return temp; } /* * Note! This is subtle. We jump to wake people up only if * the semaphore was negative (== somebody was waiting on it). * The default case (no contention) will result in NO * jumps for both down() and up(). */ extern inline void up(struct semaphore * sem) { unsigned int cpsr, temp; __asm__ __volatile__ (" @ atomic up operation mrs %0, cpsr orr %1, %0, #128 @ disable IRQs msr cpsr, %1 ldr %1, [%2] bic %0, %0, #0x80000000 @ clear N adds %1, %1, #1 str %1, [%2] orrle %0, %0, #0x80000000 @ set N msr cpsr, %0 movmi r0, %2 blmi " SYMBOL_NAME_STR(__up_wakeup) : "=&r" (cpsr), "=&r" (temp) : "r" (sem) : "r0", "lr", "cc"); } #endif |