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 #error "Cribbed from linux-2.6/include/asm-arm/atomic.h but untested"
   7
   8 #ifdef __KERNEL__
   9
  10 #if __LINUX_ARM_ARCH__ >= 6
  11
  12 static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new)
  13 {
  14         unsigned long oldval, res;
  15
  16         do {
  17                 __asm__ __volatile__("@ atomic_cmpxchg\n"
  18                 "ldrex  %1, [%2]\n"
  19                 "mov    %0, #0\n"
  20                 "teq    %1, %3\n"
  21                 "strexeq %0, %4, [%2]\n"
  22                     : "=&r" (res), "=&r" (oldval)
  23                     : "r" (&ptr->counter), "Ir" (old), "r" (new)
  24                     : "cc");
  25         } while (res);
  26
  27         return oldval;
  28 }
  29
  30 #else /* ARM_ARCH_6 */
  31
  32 #include <asm/system.h>
  33
  34 #ifdef CONFIG_SMP
  35 #error SMP not supported on pre-ARMv6 CPUs
  36 #endif
  37
  38 static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
  39 {
  40         int ret;
  41         unsigned long flags;
  42
  43         raw_local_irq_save(flags);
  44         ret = v->counter;
  45         if (likely(ret == old))
  46                 v->counter = new;
  47         raw_local_irq_restore(flags);
  48
  49         return ret;
  50 }
  51
  52 #endif /* __LINUX_ARM_ARCH__ */
  53
  54 #endif /* __KERNEL__ */
  55
  56 #endif /* asm/atomic.h */