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