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[0];
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  */
op_cpu_buffer_reset(int cpu)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
op_cpu_buffer_add_data(struct op_entry * entry,unsigned long val)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
op_cpu_buffer_get_size(struct op_entry * entry)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
op_cpu_buffer_get_data(struct op_entry * entry,unsigned long * val)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 */
122