drivers/oprofile/cpu_buffer.h

   1 /**
   2  * @file cpu_buffer.h
   3  *
   4  * @remark Copyright 2002-2009 OProfile authors
   5  * @remark Read the file COPYING
   6  *
   7  * @author John Levon <levon@movementarian.org>
   8  * @author Robert Richter <robert.richter@amd.com>
   9  */
  10
  11 #ifndef OPROFILE_CPU_BUFFER_H
  12 #define OPROFILE_CPU_BUFFER_H
  13
  14 #include <linux/types.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/cache.h>
  18 #include <linux/sched.h>
  19 #include <linux/ring_buffer.h>
  20
  21 struct task_struct;
  22
  23 int alloc_cpu_buffers(void);
  24 void free_cpu_buffers(void);
  25
  26 void start_cpu_work(void);
  27 void end_cpu_work(void);
  28
  29 /* CPU buffer is composed of such entries (which are
  30  * also used for context switch notes)
  31  */
  32 struct op_sample {
  33         unsigned long eip;
  34         unsigned long event;
  35         unsigned long data[0];
  36 };
  37
  38 struct op_entry;
  39
  40 struct oprofile_cpu_buffer {
  41         unsigned long buffer_size;
  42         struct task_struct *last_task;
  43         int last_is_kernel;
  44         int tracing;
  45         unsigned long sample_received;
  46         unsigned long sample_lost_overflow;
  47         unsigned long backtrace_aborted;
  48         unsigned long sample_invalid_eip;
  49         int cpu;
  50         struct delayed_work work;
  51 };
  52
  53 DECLARE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer);
  54
  55 /*
  56  * Resets the cpu buffer to a sane state.
  57  *
  58  * reset these to invalid values; the next sample collected will
  59  * populate the buffer with proper values to initialize the buffer
  60  */
  61 static inline void op_cpu_buffer_reset(int cpu)
  62 {
  63         struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu);
  64
  65         cpu_buf->last_is_kernel = -1;
  66         cpu_buf->last_task = NULL;
  67 }
  68
  69 /*
  70  * op_cpu_buffer_add_data() and op_cpu_buffer_write_commit() may be
  71  * called only if op_cpu_buffer_write_reserve() did not return NULL or
  72  * entry->event != NULL, otherwise entry->size or entry->event will be
  73  * used uninitialized.
  74  */
  75
  76 struct op_sample
  77 *op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size);
  78 int op_cpu_buffer_write_commit(struct op_entry *entry);
  79 struct op_sample *op_cpu_buffer_read_entry(struct op_entry *entry, int cpu);
  80 unsigned long op_cpu_buffer_entries(int cpu);
  81
  82 /* returns the remaining free size of data in the entry */
  83 static inline
  84 int op_cpu_buffer_add_data(struct op_entry *entry, unsigned long val)
  85 {
  86         if (!entry->size)
  87                 return 0;
  88         *entry->data = val;
  89         entry->size--;
  90         entry->data++;
  91         return entry->size;
  92 }
  93
  94 /* returns the size of data in the entry */
  95 static inline
  96 int op_cpu_buffer_get_size(struct op_entry *entry)
  97 {
  98         return entry->size;
  99 }
 100
 101 /* returns 0 if empty or the size of data including the current value */
 102 static inline
 103 int op_cpu_buffer_get_data(struct op_entry *entry, unsigned long *val)
 104 {
 105         int size = entry->size;
 106         if (!size)
 107                 return 0;
 108         *val = *entry->data;
 109         entry->size--;
 110         entry->data++;
 111         return size;
 112 }
 113
 114 /* extra data flags */
 115 #define KERNEL_CTX_SWITCH       (1UL << 0)
 116 #define IS_KERNEL               (1UL << 1)
 117 #define TRACE_BEGIN             (1UL << 2)
 118 #define USER_CTX_SWITCH         (1UL << 3)
 119
 120 #endif /* OPROFILE_CPU_BUFFER_H */