trunk/obsolete/ltt-usertrace/ltt/kernelutils-arm.h

   1 /*****************************************************************************
   2  * kernelutils-arm.h
   3  *
   4  * This file holds the code needed by LTT usertrace that comes from the
   5  * kernel headers.  Since including kernel headers is not recommended in
   6  * userspace programs/libraries, we rewrote implementations HIGHLY INSPIRED
   7  * (i.e. copied/pasted) from the original kernel headers (2.6.18).
   8  *
   9  * Do not use these functions within signal handlers, as the architecture offers
  10  * no atomic operations. (Mathieu Desnoyers) It is safe to do multithreaded
  11  * tracing though, as the buffers are per thread.
  12  *
  13  * Deepak Saxena, October 2006
  14  */
  15
  16 #ifndef _KERNELUTILS_ARM_H
  17 #define _KERNELUTILS_ARM_H
  18
  19 #include <time.h>
  20
  21 #ifdef __cplusplus
  22 extern "C" {
  23 #endif
  24
  25 typedef struct { volatile int counter; } atomic_t;
  26
  27 #define atomic_read(v)  ((v)->counter)
  28
  29 static inline int atomic_add_return(int i, atomic_t *v)
  30 {
  31         unsigned long flags;
  32         int val;
  33
  34         val = v->counter;
  35         v->counter = val += i;
  36
  37         return val;
  38 }
  39
  40 #define atomic_add(i, v)        (void) atomic_add_return(i, v)
  41 #define atomic_inc(v)           (void) atomic_add_return(1, v)
  42
  43 static inline unsigned long cmpxchg(volatile void *ptr,
  44                                     unsigned long old,
  45                                     unsigned long new)
  46 {
  47         unsigned long flags, prev;
  48         volatile unsigned long *p = ptr;
  49
  50         if ((prev = *p) == old)
  51                 *p = new;
  52         return(prev);
  53 }
  54
  55 static inline unsigned long long get_cycles(void)
  56 {
  57         struct timespec tp;
  58         clock_gettime(CLOCK_MONOTONIC, &tp);
  59         return tp.tv_sec * 1000000000 + tp.tv_nsec;
  60 }
  61
  62
  63 #ifdef __cplusplus
  64 } /* end of extern "C" */
  65 #endif
  66
  67 #endif