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 void flush_cpu_work(void);
  29
  30 /* CPU buffer is composed of such entries (which are
  31  * also used for context switch notes)
  32  */
  33 struct op_sample {
  34         unsigned long eip;
  35         unsigned long event;
  36         unsigned long data[];
  37 };
  38
  39 struct op_entry;
  40
  41 struct oprofile_cpu_buffer {
  42         unsigned long buffer_size;
  43         struct task_struct *last_task;
  44         int last_is_kernel;
  45         int tracing;
  46         unsigned long sample_received;
  47         unsigned long sample_lost_overflow;
  48         unsigned long backtrace_aborted;
  49         unsigned long sample_invalid_eip;
  50         int cpu;
  51         struct delayed_work work;
  52 };
  53
  54 DECLARE_PER_CPU(struct oprofile_cpu_buffer, op_cpu_buffer);
  55
  56 /*
  57  * Resets the cpu buffer to a sane state.
  58  *
  59  * reset these to invalid values; the next sample collected will
  60  * populate the buffer with proper values to initialize the buffer
  61  */
  62 static inline void op_cpu_buffer_reset(int cpu)
  63 {
  64         struct oprofile_cpu_buffer *cpu_buf = &per_cpu(op_cpu_buffer, cpu);
  65
  66         cpu_buf->last_is_kernel = -1;
  67         cpu_buf->last_task = NULL;
  68 }
  69
  70 /*
  71  * op_cpu_buffer_add_data() and op_cpu_buffer_write_commit() may be
  72  * called only if op_cpu_buffer_write_reserve() did not return NULL or
  73  * entry->event != NULL, otherwise entry->size or entry->event will be
  74  * used uninitialized.
  75  */
  76
  77 struct op_sample
  78 *op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size);
  79 int op_cpu_buffer_write_commit(struct op_entry *entry);
  80 struct op_sample *op_cpu_buffer_read_entry(struct op_entry *entry, int cpu);
  81 unsigned long op_cpu_buffer_entries(int cpu);
  82
  83 /* returns the remaining free size of data in the entry */
  84 static inline
  85 int op_cpu_buffer_add_data(struct op_entry *entry, unsigned long val)
  86 {
  87         if (!entry->size)
  88                 return 0;
  89         *entry->data = val;
  90         entry->size--;
  91         entry->data++;
  92         return entry->size;
  93 }
  94
  95 /* returns the size of data in the entry */
  96 static inline
  97 int op_cpu_buffer_get_size(struct op_entry *entry)
  98 {
  99         return entry->size;
 100 }
 101
 102 /* returns 0 if empty or the size of data including the current value */
 103 static inline
 104 int op_cpu_buffer_get_data(struct op_entry *entry, unsigned long *val)
 105 {
 106         int size = entry->size;
 107         if (!size)
 108                 return 0;
 109         *val = *entry->data;
 110         entry->size--;
 111         entry->data++;
 112         return size;
 113 }
 114
 115 /* extra data flags */
 116 #define KERNEL_CTX_SWITCH       (1UL << 0)
 117 #define IS_KERNEL               (1UL << 1)
 118 #define TRACE_BEGIN             (1UL << 2)
 119 #define USER_CTX_SWITCH         (1UL << 3)
 120
 121 #endif /* OPROFILE_CPU_BUFFER_H */