LXR linux/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/errno.h>
  13
  14/*
  15 * These two _must_ execute atomically wrt each other.
  16 */
  17static inline void wake_one_more(struct semaphore * sem)
  18{
  19        atomic_inc(&sem->waking);
  20}
  21
  22#ifndef CONFIG_RMW_INSNS
  23extern spinlock_t semaphore_wake_lock;
  24#endif
  25
  26static 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 */
  63static 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        }
  98next:
  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 */
 109static 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
 143