pintos-os.org Git - openvswitch/blob - datapath/linux-2.4/compat-2.4/include-arm/asm/atomic.h

   1 #ifndef __ASM_ARM_ATOMIC_H_WRAPPER
   2 #define __ASM_ARM_ATOMIC_H_WRAPPER 1
   3
   4 #include_next <asm/atomic.h>
   5
   6 #ifdef __KERNEL__
   7
   8 #if __LINUX_ARM_ARCH__ >= 6
   9
  10 static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new)
  11 {
  12         unsigned long oldval, res;
  13
  14         do {
  15                 __asm__ __volatile__("@ atomic_cmpxchg\n"
  16                 "ldrex  %1, [%2]\n"
  17                 "mov    %0, #0\n"
  18                 "teq    %1, %3\n"
  19                 "strexeq %0, %4, [%2]\n"
  20                     : "=&r" (res), "=&r" (oldval)
  21                     : "r" (&ptr->counter), "Ir" (old), "r" (new)
  22                     : "cc");
  23         } while (res);
  24
  25         return oldval;
  26 }
  27
  28 #else /* ARM_ARCH_6 */
  29
  30 #include <asm/system.h>
  31
  32 #ifdef CONFIG_SMP
  33 #error SMP not supported on pre-ARMv6 CPUs
  34 #endif
  35
  36 static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
  37 {
  38         int ret;
  39         unsigned long flags;
  40
  41         local_irq_save(flags);
  42         ret = v->counter;
  43         if (likely(ret == old))
  44                 v->counter = new;
  45         local_irq_restore(flags);
  46
  47         return ret;
  48 }
  49
  50 #endif /* __LINUX_ARM_ARCH__ */
  51
  52 #endif /* __KERNEL__ */
  53
  54 #endif /* asm/atomic.h */