i386/linux/linux-2.3.21/include/asm-m68k/semaphore-helper.h

   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/config.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 static inline int waking_non_zero(struct semaphore *sem)
  23 {
  24         int ret;
  25 #ifndef CONFIG_RMW_INSNS
  26         unsigned long flags;
  27
  28         spin_lock_irqsave(&semaphore_wake_lock, flags);
  29         ret = 0;
  30         if (atomic_read(&sem->waking) > 0) {
  31                 atomic_dec(&sem->waking);
  32                 ret = 1;
  33         }
  34         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  35 #else
  36         int tmp1, tmp2;
  37
  38         __asm__ __volatile__
  39           ("1:  movel   %1,%2\n"
  40            "    jle     2f\n"
  41            "    subql   #1,%2\n"
  42            "    casl    %1,%2,%3\n"
  43            "    jne     1b\n"
  44            "    moveq   #1,%0\n"
  45            "2:"
  46            : "=d" (ret), "=d" (tmp1), "=d" (tmp2)
  47            : "m" (sem->waking), "0" (0), "1" (sem->waking));
  48 #endif
  49
  50         return ret;
  51 }
  52
  53 /*
  54  * waking_non_zero_interruptible:
  55  *      1       got the lock
  56  *      0       go to sleep
  57  *      -EINTR  interrupted
  58  */
  59 static inline int waking_non_zero_interruptible(struct semaphore *sem,
  60                                                 struct task_struct *tsk)
  61 {
  62         int ret;
  63 #ifndef CONFIG_RMW_INSNS
  64         unsigned long flags;
  65
  66         spin_lock_irqsave(&semaphore_wake_lock, flags);
  67         ret = 0;
  68         if (atomic_read(&sem->waking) > 0) {
  69                 atomic_dec(&sem->waking);
  70                 ret = 1;
  71         } else if (signal_pending(tsk)) {
  72                 atomic_inc(&sem->count);
  73                 ret = -EINTR;
  74         }
  75         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  76 #else
  77         int tmp1, tmp2;
  78
  79         __asm__ __volatile__
  80           ("1:  movel   %1,%2\n"
  81            "    jle     2f\n"
  82            "    subql   #1,%2\n"
  83            "    casl    %1,%2,%3\n"
  84            "    jne     1b\n"
  85            "    moveq   #1,%0\n"
  86            "    jra     %a4\n"
  87            "2:"
  88            : "=d" (ret), "=d" (tmp1), "=d" (tmp2)
  89            : "m" (sem->waking), "i" (&&next), "0" (0), "1" (sem->waking));
  90         if (signal_pending(tsk)) {
  91                 atomic_inc(&sem->count);
  92                 ret = -EINTR;
  93         }
  94 next:
  95 #endif
  96
  97         return ret;
  98 }
  99
 100 /*
 101  * waking_non_zero_trylock:
 102  *      1       failed to lock
 103  *      0       got the lock
 104  */
 105 static inline int waking_non_zero_trylock(struct semaphore *sem)
 106 {
 107         int ret;
 108 #ifndef CONFIG_RMW_INSNS
 109         unsigned long flags;
 110
 111         spin_lock_irqsave(&semaphore_wake_lock, flags);
 112         ret = 1;
 113         if (atomic_read(&sem->waking) > 0) {
 114                 atomic_dec(&sem->waking);
 115                 ret = 0;
 116         } else
 117                 atomic_inc(&sem->count);
 118         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
 119 #else
 120         int tmp1, tmp2;
 121
 122         __asm__ __volatile__
 123           ("1:  movel   %1,%2\n"
 124            "    jle     2f\n"
 125            "    subql   #1,%2\n"
 126            "    casl    %1,%2,%3\n"
 127            "    jne     1b\n"
 128            "    moveq   #0,%0\n"
 129            "2:"
 130            : "=d" (ret), "=d" (tmp1), "=d" (tmp2)
 131            : "m" (sem->waking), "0" (1), "1" (sem->waking));
 132         if (ret)
 133                 atomic_inc(&sem->count);
 134 #endif
 135         return ret;
 136 }
 137
 138 #endif