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11#include "qemu/osdep.h"
12#ifndef _WIN32
13#include <pthread.h>
14#endif
15#include "qemu/timer.h"
16#include "trace/control.h"
17#include "trace/simple.h"
18#include "qemu/error-report.h"
19#include "qemu/qemu-print.h"
20
21
22#define HEADER_EVENT_ID (~(uint64_t)0)
23
24
25#define HEADER_MAGIC 0xf2b177cb0aa429b4ULL
26
27
28#define HEADER_VERSION 4
29
30
31#define DROPPED_EVENT_ID (~(uint64_t)0 - 1)
32
33
34#define TRACE_RECORD_VALID ((uint64_t)1 << 63)
35
36
37
38
39
40static GMutex trace_lock;
41static GCond trace_available_cond;
42static GCond trace_empty_cond;
43
44static bool trace_available;
45static bool trace_writeout_enabled;
46
47enum {
48 TRACE_BUF_LEN = 4096 * 64,
49 TRACE_BUF_FLUSH_THRESHOLD = TRACE_BUF_LEN / 4,
50};
51
52uint8_t trace_buf[TRACE_BUF_LEN];
53static volatile gint trace_idx;
54static unsigned int writeout_idx;
55static volatile gint dropped_events;
56static uint32_t trace_pid;
57static FILE *trace_fp;
58static char *trace_file_name;
59
60#define TRACE_RECORD_TYPE_MAPPING 0
61#define TRACE_RECORD_TYPE_EVENT 1
62
63
64typedef struct {
65 uint64_t event;
66 uint64_t timestamp_ns;
67 uint32_t length;
68 uint32_t pid;
69 uint64_t arguments[];
70} TraceRecord;
71
72typedef struct {
73 uint64_t header_event_id;
74 uint64_t header_magic;
75 uint64_t header_version;
76} TraceLogHeader;
77
78
79static void read_from_buffer(unsigned int idx, void *dataptr, size_t size);
80static unsigned int write_to_buffer(unsigned int idx, void *dataptr, size_t size);
81
82static void clear_buffer_range(unsigned int idx, size_t len)
83{
84 uint32_t num = 0;
85 while (num < len) {
86 if (idx >= TRACE_BUF_LEN) {
87 idx = idx % TRACE_BUF_LEN;
88 }
89 trace_buf[idx++] = 0;
90 num++;
91 }
92}
93
94
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98
99
100
101static bool get_trace_record(unsigned int idx, TraceRecord **recordptr)
102{
103 uint64_t event_flag = 0;
104 TraceRecord record;
105
106 read_from_buffer(idx, &record, sizeof(event_flag));
107
108 if (!(record.event & TRACE_RECORD_VALID)) {
109 return false;
110 }
111
112 smp_rmb();
113
114 read_from_buffer(idx, &record, sizeof(TraceRecord));
115 *recordptr = malloc(record.length);
116
117 read_from_buffer(idx, *recordptr, record.length);
118 smp_rmb();
119 (*recordptr)->event &= ~TRACE_RECORD_VALID;
120
121
122
123
124 clear_buffer_range(idx, record.length);
125 return true;
126}
127
128
129
130
131
132
133static void flush_trace_file(bool wait)
134{
135 g_mutex_lock(&trace_lock);
136 trace_available = true;
137 g_cond_signal(&trace_available_cond);
138
139 if (wait) {
140 g_cond_wait(&trace_empty_cond, &trace_lock);
141 }
142
143 g_mutex_unlock(&trace_lock);
144}
145
146static void wait_for_trace_records_available(void)
147{
148 g_mutex_lock(&trace_lock);
149 while (!(trace_available && trace_writeout_enabled)) {
150 g_cond_signal(&trace_empty_cond);
151 g_cond_wait(&trace_available_cond, &trace_lock);
152 }
153 trace_available = false;
154 g_mutex_unlock(&trace_lock);
155}
156
157static gpointer writeout_thread(gpointer opaque)
158{
159 TraceRecord *recordptr;
160 union {
161 TraceRecord rec;
162 uint8_t bytes[sizeof(TraceRecord) + sizeof(uint64_t)];
163 } dropped;
164 unsigned int idx = 0;
165 int dropped_count;
166 size_t unused __attribute__ ((unused));
167 uint64_t type = TRACE_RECORD_TYPE_EVENT;
168
169 for (;;) {
170 wait_for_trace_records_available();
171
172 if (g_atomic_int_get(&dropped_events)) {
173 dropped.rec.event = DROPPED_EVENT_ID;
174 dropped.rec.timestamp_ns = get_clock();
175 dropped.rec.length = sizeof(TraceRecord) + sizeof(uint64_t);
176 dropped.rec.pid = trace_pid;
177 do {
178 dropped_count = g_atomic_int_get(&dropped_events);
179 } while (!g_atomic_int_compare_and_exchange(&dropped_events,
180 dropped_count, 0));
181 dropped.rec.arguments[0] = dropped_count;
182 unused = fwrite(&type, sizeof(type), 1, trace_fp);
183 unused = fwrite(&dropped.rec, dropped.rec.length, 1, trace_fp);
184 }
185
186 while (get_trace_record(idx, &recordptr)) {
187 unused = fwrite(&type, sizeof(type), 1, trace_fp);
188 unused = fwrite(recordptr, recordptr->length, 1, trace_fp);
189 writeout_idx += recordptr->length;
190 free(recordptr);
191 idx = writeout_idx % TRACE_BUF_LEN;
192 }
193
194 fflush(trace_fp);
195 }
196 return NULL;
197}
198
199void trace_record_write_u64(TraceBufferRecord *rec, uint64_t val)
200{
201 rec->rec_off = write_to_buffer(rec->rec_off, &val, sizeof(uint64_t));
202}
203
204void trace_record_write_str(TraceBufferRecord *rec, const char *s, uint32_t slen)
205{
206
207 rec->rec_off = write_to_buffer(rec->rec_off, &slen, sizeof(slen));
208
209 rec->rec_off = write_to_buffer(rec->rec_off, (void*)s, slen);
210}
211
212int trace_record_start(TraceBufferRecord *rec, uint32_t event, size_t datasize)
213{
214 unsigned int idx, rec_off, old_idx, new_idx;
215 uint32_t rec_len = sizeof(TraceRecord) + datasize;
216 uint64_t event_u64 = event;
217 uint64_t timestamp_ns = get_clock();
218
219 do {
220 old_idx = g_atomic_int_get(&trace_idx);
221 smp_rmb();
222 new_idx = old_idx + rec_len;
223
224 if (new_idx - writeout_idx > TRACE_BUF_LEN) {
225
226 g_atomic_int_inc(&dropped_events);
227 return -ENOSPC;
228 }
229 } while (!g_atomic_int_compare_and_exchange(&trace_idx, old_idx, new_idx));
230
231 idx = old_idx % TRACE_BUF_LEN;
232
233 rec_off = idx;
234 rec_off = write_to_buffer(rec_off, &event_u64, sizeof(event_u64));
235 rec_off = write_to_buffer(rec_off, ×tamp_ns, sizeof(timestamp_ns));
236 rec_off = write_to_buffer(rec_off, &rec_len, sizeof(rec_len));
237 rec_off = write_to_buffer(rec_off, &trace_pid, sizeof(trace_pid));
238
239 rec->tbuf_idx = idx;
240 rec->rec_off = (idx + sizeof(TraceRecord)) % TRACE_BUF_LEN;
241 return 0;
242}
243
244static void read_from_buffer(unsigned int idx, void *dataptr, size_t size)
245{
246 uint8_t *data_ptr = dataptr;
247 uint32_t x = 0;
248 while (x < size) {
249 if (idx >= TRACE_BUF_LEN) {
250 idx = idx % TRACE_BUF_LEN;
251 }
252 data_ptr[x++] = trace_buf[idx++];
253 }
254}
255
256static unsigned int write_to_buffer(unsigned int idx, void *dataptr, size_t size)
257{
258 uint8_t *data_ptr = dataptr;
259 uint32_t x = 0;
260 while (x < size) {
261 if (idx >= TRACE_BUF_LEN) {
262 idx = idx % TRACE_BUF_LEN;
263 }
264 trace_buf[idx++] = data_ptr[x++];
265 }
266 return idx;
267}
268
269void trace_record_finish(TraceBufferRecord *rec)
270{
271 TraceRecord record;
272 read_from_buffer(rec->tbuf_idx, &record, sizeof(TraceRecord));
273 smp_wmb();
274 record.event |= TRACE_RECORD_VALID;
275 write_to_buffer(rec->tbuf_idx, &record, sizeof(TraceRecord));
276
277 if (((unsigned int)g_atomic_int_get(&trace_idx) - writeout_idx)
278 > TRACE_BUF_FLUSH_THRESHOLD) {
279 flush_trace_file(false);
280 }
281}
282
283static int st_write_event_mapping(TraceEventIter *iter)
284{
285 uint64_t type = TRACE_RECORD_TYPE_MAPPING;
286 TraceEvent *ev;
287
288 while ((ev = trace_event_iter_next(iter)) != NULL) {
289 uint64_t id = trace_event_get_id(ev);
290 const char *name = trace_event_get_name(ev);
291 uint32_t len = strlen(name);
292 if (fwrite(&type, sizeof(type), 1, trace_fp) != 1 ||
293 fwrite(&id, sizeof(id), 1, trace_fp) != 1 ||
294 fwrite(&len, sizeof(len), 1, trace_fp) != 1 ||
295 fwrite(name, len, 1, trace_fp) != 1) {
296 return -1;
297 }
298 }
299
300 return 0;
301}
302
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306
307
308bool st_set_trace_file_enabled(bool enable)
309{
310 TraceEventIter iter;
311 bool was_enabled = trace_fp;
312
313 if (enable == !!trace_fp) {
314 return was_enabled;
315 }
316
317
318 flush_trace_file(true);
319 trace_writeout_enabled = false;
320 flush_trace_file(true);
321
322 if (enable) {
323 static const TraceLogHeader header = {
324 .header_event_id = HEADER_EVENT_ID,
325 .header_magic = HEADER_MAGIC,
326
327 .header_version = HEADER_VERSION,
328 };
329
330 trace_fp = fopen(trace_file_name, "wb");
331 if (!trace_fp) {
332 return was_enabled;
333 }
334
335 trace_event_iter_init_all(&iter);
336 if (fwrite(&header, sizeof header, 1, trace_fp) != 1 ||
337 st_write_event_mapping(&iter) < 0) {
338 fclose(trace_fp);
339 trace_fp = NULL;
340 return was_enabled;
341 }
342
343
344 trace_writeout_enabled = true;
345 flush_trace_file(false);
346 } else {
347 fclose(trace_fp);
348 trace_fp = NULL;
349 }
350 return was_enabled;
351}
352
353
354
355
356
357
358
359void st_set_trace_file(const char *file)
360{
361 bool saved_enable = st_set_trace_file_enabled(false);
362
363 g_free(trace_file_name);
364
365 if (!file) {
366
367 trace_file_name = g_strdup_printf(CONFIG_TRACE_FILE "-" FMT_pid, (pid_t)getpid());
368 } else {
369 trace_file_name = g_strdup_printf("%s", file);
370 }
371
372 st_set_trace_file_enabled(saved_enable);
373}
374
375void st_print_trace_file_status(void)
376{
377 qemu_printf("Trace file \"%s\" %s.\n",
378 trace_file_name, trace_fp ? "on" : "off");
379}
380
381void st_flush_trace_buffer(void)
382{
383 flush_trace_file(true);
384}
385
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389
390
391static GThread *trace_thread_create(GThreadFunc fn)
392{
393 GThread *thread;
394#ifndef _WIN32
395 sigset_t set, oldset;
396
397 sigfillset(&set);
398 pthread_sigmask(SIG_SETMASK, &set, &oldset);
399#endif
400
401 thread = g_thread_new("trace-thread", fn, NULL);
402
403#ifndef _WIN32
404 pthread_sigmask(SIG_SETMASK, &oldset, NULL);
405#endif
406
407 return thread;
408}
409
410bool st_init(void)
411{
412 GThread *thread;
413
414 trace_pid = getpid();
415
416 thread = trace_thread_create(writeout_thread);
417 if (!thread) {
418 warn_report("unable to initialize simple trace backend");
419 return false;
420 }
421
422 atexit(st_flush_trace_buffer);
423 return true;
424}
425
426void st_init_group(size_t group)
427{
428 TraceEventIter iter;
429
430 if (!trace_writeout_enabled) {
431 return;
432 }
433
434 trace_event_iter_init_group(&iter, group);
435 st_write_event_mapping(&iter);
436}
437