x86: Save/restore PAT MSR
[qemu.git] / simpletrace.c
blob9926ab39bb25a53f66cde4223faa47d5013290ca
1 /*
2 * Simple trace backend
4 * Copyright IBM, Corp. 2010
6 * This work is licensed under the terms of the GNU GPL, version 2. See
7 * the COPYING file in the top-level directory.
9 */
11 #include <stdlib.h>
12 #include <stdint.h>
13 #include <stdio.h>
14 #include <time.h>
15 #include <signal.h>
16 #include <pthread.h>
17 #include "qerror.h"
18 #include "qemu-timer.h"
19 #include "trace.h"
21 /** Trace file header event ID */
22 #define HEADER_EVENT_ID (~(uint64_t)0) /* avoids conflicting with TraceEventIDs */
24 /** Trace file magic number */
25 #define HEADER_MAGIC 0xf2b177cb0aa429b4ULL
27 /** Trace file version number, bump if format changes */
28 #define HEADER_VERSION 0
30 /** Records were dropped event ID */
31 #define DROPPED_EVENT_ID (~(uint64_t)0 - 1)
33 /** Trace record is valid */
34 #define TRACE_RECORD_VALID ((uint64_t)1 << 63)
36 /** Trace buffer entry */
37 typedef struct {
38 uint64_t event;
39 uint64_t timestamp_ns;
40 uint64_t x1;
41 uint64_t x2;
42 uint64_t x3;
43 uint64_t x4;
44 uint64_t x5;
45 uint64_t x6;
46 } TraceRecord;
48 enum {
49 TRACE_BUF_LEN = 4096,
50 TRACE_BUF_FLUSH_THRESHOLD = TRACE_BUF_LEN / 4,
54 * Trace records are written out by a dedicated thread. The thread waits for
55 * records to become available, writes them out, and then waits again.
57 static pthread_mutex_t trace_lock = PTHREAD_MUTEX_INITIALIZER;
58 static pthread_cond_t trace_available_cond = PTHREAD_COND_INITIALIZER;
59 static pthread_cond_t trace_empty_cond = PTHREAD_COND_INITIALIZER;
60 static bool trace_available;
61 static bool trace_writeout_enabled;
63 static TraceRecord trace_buf[TRACE_BUF_LEN];
64 static unsigned int trace_idx;
65 static FILE *trace_fp;
66 static char *trace_file_name = NULL;
68 /**
69 * Read a trace record from the trace buffer
71 * @idx Trace buffer index
72 * @record Trace record to fill
74 * Returns false if the record is not valid.
76 static bool get_trace_record(unsigned int idx, TraceRecord *record)
78 if (!(trace_buf[idx].event & TRACE_RECORD_VALID)) {
79 return false;
82 __sync_synchronize(); /* read memory barrier before accessing record */
84 *record = trace_buf[idx];
85 record->event &= ~TRACE_RECORD_VALID;
86 return true;
89 /**
90 * Kick writeout thread
92 * @wait Whether to wait for writeout thread to complete
94 static void flush_trace_file(bool wait)
96 pthread_mutex_lock(&trace_lock);
97 trace_available = true;
98 pthread_cond_signal(&trace_available_cond);
100 if (wait) {
101 pthread_cond_wait(&trace_empty_cond, &trace_lock);
104 pthread_mutex_unlock(&trace_lock);
107 static void wait_for_trace_records_available(void)
109 pthread_mutex_lock(&trace_lock);
110 while (!(trace_available && trace_writeout_enabled)) {
111 pthread_cond_signal(&trace_empty_cond);
112 pthread_cond_wait(&trace_available_cond, &trace_lock);
114 trace_available = false;
115 pthread_mutex_unlock(&trace_lock);
118 static void *writeout_thread(void *opaque)
120 TraceRecord record;
121 unsigned int writeout_idx = 0;
122 unsigned int num_available, idx;
123 size_t unused;
125 for (;;) {
126 wait_for_trace_records_available();
128 num_available = trace_idx - writeout_idx;
129 if (num_available > TRACE_BUF_LEN) {
130 record = (TraceRecord){
131 .event = DROPPED_EVENT_ID,
132 .x1 = num_available,
134 unused = fwrite(&record, sizeof(record), 1, trace_fp);
135 writeout_idx += num_available;
138 idx = writeout_idx % TRACE_BUF_LEN;
139 while (get_trace_record(idx, &record)) {
140 trace_buf[idx].event = 0; /* clear valid bit */
141 unused = fwrite(&record, sizeof(record), 1, trace_fp);
142 idx = ++writeout_idx % TRACE_BUF_LEN;
145 fflush(trace_fp);
147 return NULL;
150 static void trace(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3,
151 uint64_t x4, uint64_t x5, uint64_t x6)
153 unsigned int idx;
154 uint64_t timestamp;
156 if (!trace_list[event].state) {
157 return;
160 timestamp = get_clock();
162 idx = __sync_fetch_and_add(&trace_idx, 1) % TRACE_BUF_LEN;
163 trace_buf[idx] = (TraceRecord){
164 .event = event,
165 .timestamp_ns = timestamp,
166 .x1 = x1,
167 .x2 = x2,
168 .x3 = x3,
169 .x4 = x4,
170 .x5 = x5,
171 .x6 = x6,
173 __sync_synchronize(); /* write barrier before marking as valid */
174 trace_buf[idx].event |= TRACE_RECORD_VALID;
176 if ((idx + 1) % TRACE_BUF_FLUSH_THRESHOLD == 0) {
177 flush_trace_file(false);
181 void trace0(TraceEventID event)
183 trace(event, 0, 0, 0, 0, 0, 0);
186 void trace1(TraceEventID event, uint64_t x1)
188 trace(event, x1, 0, 0, 0, 0, 0);
191 void trace2(TraceEventID event, uint64_t x1, uint64_t x2)
193 trace(event, x1, x2, 0, 0, 0, 0);
196 void trace3(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3)
198 trace(event, x1, x2, x3, 0, 0, 0);
201 void trace4(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4)
203 trace(event, x1, x2, x3, x4, 0, 0);
206 void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5)
208 trace(event, x1, x2, x3, x4, x5, 0);
211 void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5, uint64_t x6)
213 trace(event, x1, x2, x3, x4, x5, x6);
216 void st_set_trace_file_enabled(bool enable)
218 if (enable == !!trace_fp) {
219 return; /* no change */
222 /* Halt trace writeout */
223 flush_trace_file(true);
224 trace_writeout_enabled = false;
225 flush_trace_file(true);
227 if (enable) {
228 static const TraceRecord header = {
229 .event = HEADER_EVENT_ID,
230 .timestamp_ns = HEADER_MAGIC,
231 .x1 = HEADER_VERSION,
234 trace_fp = fopen(trace_file_name, "w");
235 if (!trace_fp) {
236 return;
239 if (fwrite(&header, sizeof header, 1, trace_fp) != 1) {
240 fclose(trace_fp);
241 trace_fp = NULL;
242 return;
245 /* Resume trace writeout */
246 trace_writeout_enabled = true;
247 flush_trace_file(false);
248 } else {
249 fclose(trace_fp);
250 trace_fp = NULL;
255 * Set the name of a trace file
257 * @file The trace file name or NULL for the default name-<pid> set at
258 * config time
260 bool st_set_trace_file(const char *file)
262 st_set_trace_file_enabled(false);
264 free(trace_file_name);
266 if (!file) {
267 if (asprintf(&trace_file_name, CONFIG_TRACE_FILE, getpid()) < 0) {
268 trace_file_name = NULL;
269 return false;
271 } else {
272 if (asprintf(&trace_file_name, "%s", file) < 0) {
273 trace_file_name = NULL;
274 return false;
278 st_set_trace_file_enabled(true);
279 return true;
282 void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...))
284 stream_printf(stream, "Trace file \"%s\" %s.\n",
285 trace_file_name, trace_fp ? "on" : "off");
288 void st_print_trace(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...))
290 unsigned int i;
292 for (i = 0; i < TRACE_BUF_LEN; i++) {
293 TraceRecord record;
295 if (!get_trace_record(i, &record)) {
296 continue;
298 stream_printf(stream, "Event %" PRIu64 " : %" PRIx64 " %" PRIx64
299 " %" PRIx64 " %" PRIx64 " %" PRIx64 " %" PRIx64 "\n",
300 record.event, record.x1, record.x2,
301 record.x3, record.x4, record.x5,
302 record.x6);
306 void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...))
308 unsigned int i;
310 for (i = 0; i < NR_TRACE_EVENTS; i++) {
311 stream_printf(stream, "%s [Event ID %u] : state %u\n",
312 trace_list[i].tp_name, i, trace_list[i].state);
316 bool st_change_trace_event_state(const char *name, bool enabled)
318 unsigned int i;
320 for (i = 0; i < NR_TRACE_EVENTS; i++) {
321 if (!strcmp(trace_list[i].tp_name, name)) {
322 trace_list[i].state = enabled;
323 return true;
326 return false;
329 void st_flush_trace_buffer(void)
331 flush_trace_file(true);
334 void st_init(const char *file)
336 pthread_t thread;
337 pthread_attr_t attr;
338 sigset_t set, oldset;
339 int ret;
341 pthread_attr_init(&attr);
342 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
344 sigfillset(&set);
345 pthread_sigmask(SIG_SETMASK, &set, &oldset);
346 ret = pthread_create(&thread, &attr, writeout_thread, NULL);
347 pthread_sigmask(SIG_SETMASK, &oldset, NULL);
349 if (ret != 0) {
350 error_report("warning: unable to create trace file thread\n");
351 return;
354 atexit(st_flush_trace_buffer);
355 st_set_trace_file(file);