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26f7227b SH |
1 | /* |
2 | * Simple trace backend | |
3 | * | |
4 | * Copyright IBM, Corp. 2010 | |
5 | * | |
6 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
7 | * the COPYING file in the top-level directory. | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <stdlib.h> | |
12 | #include <stdint.h> | |
13 | #include <stdio.h> | |
14 | #include <time.h> | |
15 | #include "trace.h" | |
16 | ||
17 | /** Trace file header event ID */ | |
18 | #define HEADER_EVENT_ID (~(uint64_t)0) /* avoids conflicting with TraceEventIDs */ | |
19 | ||
20 | /** Trace file magic number */ | |
21 | #define HEADER_MAGIC 0xf2b177cb0aa429b4ULL | |
22 | ||
23 | /** Trace file version number, bump if format changes */ | |
24 | #define HEADER_VERSION 0 | |
25 | ||
26 | /** Trace buffer entry */ | |
27 | typedef struct { | |
28 | uint64_t event; | |
29 | uint64_t timestamp_ns; | |
30 | uint64_t x1; | |
31 | uint64_t x2; | |
32 | uint64_t x3; | |
33 | uint64_t x4; | |
34 | uint64_t x5; | |
35 | uint64_t x6; | |
36 | } TraceRecord; | |
37 | ||
38 | enum { | |
39 | TRACE_BUF_LEN = 64 * 1024 / sizeof(TraceRecord), | |
40 | }; | |
41 | ||
42 | static TraceRecord trace_buf[TRACE_BUF_LEN]; | |
43 | static unsigned int trace_idx; | |
44 | static FILE *trace_fp; | |
45 | ||
46 | static bool write_header(FILE *fp) | |
47 | { | |
48 | static const TraceRecord header = { | |
49 | .event = HEADER_EVENT_ID, | |
50 | .timestamp_ns = HEADER_MAGIC, | |
51 | .x1 = HEADER_VERSION, | |
52 | }; | |
53 | ||
54 | return fwrite(&header, sizeof header, 1, fp) == 1; | |
55 | } | |
56 | ||
57 | static void flush_trace_buffer(void) | |
58 | { | |
59 | if (!trace_fp) { | |
60 | trace_fp = fopen("trace.log", "w"); | |
61 | if (trace_fp) { | |
62 | write_header(trace_fp); | |
63 | } | |
64 | } | |
65 | if (trace_fp) { | |
66 | size_t unused; /* for when fwrite(3) is declared warn_unused_result */ | |
67 | unused = fwrite(trace_buf, trace_idx * sizeof(trace_buf[0]), 1, trace_fp); | |
68 | } | |
69 | ||
70 | /* Discard written trace records */ | |
71 | trace_idx = 0; | |
72 | } | |
73 | ||
74 | void st_set_trace_file_enabled(bool enable) | |
75 | { | |
76 | if (enable == trace_file_enabled) { | |
77 | return; /* no change */ | |
78 | } | |
79 | ||
80 | /* Flush/discard trace buffer */ | |
81 | st_flush_trace_buffer(); | |
82 | ||
83 | /* To disable, close trace file */ | |
84 | if (!enable) { | |
85 | fclose(trace_fp); | |
86 | trace_fp = NULL; | |
87 | } | |
88 | ||
89 | trace_file_enabled = enable; | |
90 | } | |
91 | ||
92 | static void trace(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, | |
93 | uint64_t x4, uint64_t x5, uint64_t x6) | |
94 | { | |
95 | TraceRecord *rec = &trace_buf[trace_idx]; | |
96 | struct timespec ts; | |
97 | ||
98 | /* TODO Windows? It would be good to use qemu-timer here but that isn't | |
99 | * linked into qemu-tools. Also we should avoid recursion in the tracing | |
100 | * code, therefore it is useful to be self-contained. | |
101 | */ | |
102 | clock_gettime(CLOCK_MONOTONIC, &ts); | |
103 | ||
104 | rec->event = event; | |
105 | rec->timestamp_ns = ts.tv_sec * 1000000000LL + ts.tv_nsec; | |
106 | rec->x1 = x1; | |
107 | rec->x2 = x2; | |
108 | rec->x3 = x3; | |
109 | rec->x4 = x4; | |
110 | rec->x5 = x5; | |
111 | rec->x6 = x6; | |
112 | ||
113 | if (++trace_idx == TRACE_BUF_LEN) { | |
114 | flush_trace_buffer(); | |
115 | } | |
116 | } | |
117 | ||
118 | void trace0(TraceEventID event) | |
119 | { | |
120 | trace(event, 0, 0, 0, 0, 0, 0); | |
121 | } | |
122 | ||
123 | void trace1(TraceEventID event, uint64_t x1) | |
124 | { | |
125 | trace(event, x1, 0, 0, 0, 0, 0); | |
126 | } | |
127 | ||
128 | void trace2(TraceEventID event, uint64_t x1, uint64_t x2) | |
129 | { | |
130 | trace(event, x1, x2, 0, 0, 0, 0); | |
131 | } | |
132 | ||
133 | void trace3(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3) | |
134 | { | |
135 | trace(event, x1, x2, x3, 0, 0, 0); | |
136 | } | |
137 | ||
138 | void trace4(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4) | |
139 | { | |
140 | trace(event, x1, x2, x3, x4, 0, 0); | |
141 | } | |
142 | ||
143 | void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5) | |
144 | { | |
145 | trace(event, x1, x2, x3, x4, x5, 0); | |
146 | } | |
147 | ||
148 | void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5, uint64_t x6) | |
149 | { | |
150 | trace(event, x1, x2, x3, x4, x5, x6); | |
151 | } | |
152 | ||
153 | /** | |
154 | * Flush the trace buffer on exit | |
155 | */ | |
156 | static void __attribute__((constructor)) st_init(void) | |
157 | { | |
158 | atexit(st_flush_trace_buffer); | |
159 | } |