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   1 #ifndef _M68K_SEMAPHORE_HELPER_H
   2 #define _M68K_SEMAPHORE_HELPER_H
   3
   4 /*
   5  * SMP- and interrupt-safe semaphores helper functions.
   6  *
   7  * (C) Copyright 1996 Linus Torvalds
   8  *
   9  * m68k version by Andreas Schwab
  10  */
  11
  12 #include <linux/errno.h>
  13
  14 /*
  15  * These two _must_ execute atomically wrt each other.
  16  */
  17 static inline void wake_one_more(struct semaphore * sem)
  18 {
  19         atomic_inc(&sem->waking);
  20 }
  21
  22 #ifndef CONFIG_RMW_INSNS
  23 extern spinlock_t semaphore_wake_lock;
  24 #endif
  25
  26 static inline int waking_non_zero(struct semaphore *sem)
  27 {
  28         int ret;
  29 #ifndef CONFIG_RMW_INSNS
  30         unsigned long flags;
  31
  32         spin_lock_irqsave(&semaphore_wake_lock, flags);
  33         ret = 0;
  34         if (atomic_read(&sem->waking) > 0) {
  35                 atomic_dec(&sem->waking);
  36                 ret = 1;
  37         }
  38         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  39 #else
  40         int tmp1, tmp2;
  41
  42         __asm__ __volatile__
  43           ("1:  movel   %1,%2\n"
  44            "    jle     2f\n"
  45            "    subql   #1,%2\n"
  46            "    casl    %1,%2,%3\n"
  47            "    jne     1b\n"
  48            "    moveq   #1,%0\n"
  49            "2:"
  50            : "=d" (ret), "=d" (tmp1), "=d" (tmp2)
  51            : "m" (sem->waking), "0" (0), "1" (sem->waking));
  52 #endif
  53
  54         return ret;
  55 }
  56
  57 /*
  58  * waking_non_zero_interruptible:
  59  *      1       got the lock
  60  *      0       go to sleep
  61  *      -EINTR  interrupted
  62  */
  63 static inline int waking_non_zero_interruptible(struct semaphore *sem,
  64                                                 struct task_struct *tsk)
  65 {
  66         int ret;
  67 #ifndef CONFIG_RMW_INSNS
  68         unsigned long flags;
  69
  70         spin_lock_irqsave(&semaphore_wake_lock, flags);
  71         ret = 0;
  72         if (atomic_read(&sem->waking) > 0) {
  73                 atomic_dec(&sem->waking);
  74                 ret = 1;
  75         } else if (signal_pending(tsk)) {
  76                 atomic_inc(&sem->count);
  77                 ret = -EINTR;
  78         }
  79         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  80 #else
  81         int tmp1, tmp2;
  82
  83         __asm__ __volatile__
  84           ("1:  movel   %1,%2\n"
  85            "    jle     2f\n"
  86            "    subql   #1,%2\n"
  87            "    casl    %1,%2,%3\n"
  88            "    jne     1b\n"
  89            "    moveq   #1,%0\n"
  90            "    jra     %a4\n"
  91            "2:"
  92            : "=d" (ret), "=d" (tmp1), "=d" (tmp2)
  93            : "m" (sem->waking), "i" (&&next), "0" (0), "1" (sem->waking));
  94         if (signal_pending(tsk)) {
  95                 atomic_inc(&sem->count);
  96                 ret = -EINTR;
  97         }
  98 next:
  99 #endif
 100
 101         return ret;
 102 }
 103
 104 /*
 105  * waking_non_zero_trylock:
 106  *      1       failed to lock
 107  *      0       got the lock
 108  */
 109 static inline int waking_non_zero_trylock(struct semaphore *sem)
 110 {
 111         int ret;
 112 #ifndef CONFIG_RMW_INSNS
 113         unsigned long flags;
 114
 115         spin_lock_irqsave(&semaphore_wake_lock, flags);
 116         ret = 1;
 117         if (atomic_read(&sem->waking) > 0) {
 118                 atomic_dec(&sem->waking);
 119                 ret = 0;
 120         } else
 121                 atomic_inc(&sem->count);
 122         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
 123 #else
 124         int tmp1, tmp2;
 125
 126         __asm__ __volatile__
 127           ("1:  movel   %1,%2\n"
 128            "    jle     2f\n"
 129            "    subql   #1,%2\n"
 130            "    casl    %1,%2,%3\n"
 131            "    jne     1b\n"
 132            "    moveq   #0,%0\n"
 133            "2:"
 134            : "=d" (ret), "=d" (tmp1), "=d" (tmp2)
 135            : "m" (sem->waking), "0" (1), "1" (sem->waking));
 136         if (ret)
 137                 atomic_inc(&sem->count);
 138 #endif
 139         return ret;
 140 }
 141
 142 #endif