lib/debuglog/debuglog.cpp

79 // The debug log maintains a circular buffer of debug log records,
81 // to 224 bytes of textual log message.  Records are aligned on
96 // Tail indicates the oldest message in the debug log to read
97 // from, Head indicates the next space in the debug log to write
109     dlog_t* log = &DLOG;
115     if (log->panic) {
140     spin_lock_irqsave(&log->lock, state);
144     while ((log->head - log->tail) > (DLOG_SIZE - wiresize)) {
145         uint32_t header = *reinterpret_cast<uint32_t*>(log->data + (log->tail & DLOG_MASK));
146         log->tail += DLOG_HDR_GET_FIFOLEN(header);
149     size_t offset = (log->head & DLOG_MASK);
155         memcpy(log->data + offset, &hdr, sizeof(hdr));
156         memcpy(log->data + offset + sizeof(hdr), ptr, len);
159         memcpy(log->data + offset, &hdr, fifospace);
160         memcpy(log->data, reinterpret_cast<uint8_t*>(&hdr) + fifospace, sizeof(hdr) - fifospace);
161         memcpy(log->data + (sizeof(hdr) - fifospace), ptr, len);
164         memcpy(log->data + offset, &hdr, sizeof(hdr));
167         memcpy(log->data + offset, ptr, fifospace);
168         memcpy(log->data, ptr + fifospace, len - fifospace);
170     log->head += wiresize;
172     // Need to check this before re-releasing the log lock, since we may
184     spin_unlock_irqrestore(&log->lock, state);
186     [log, holding_thread_lock]() TA_NO_THREAD_SAFETY_ANALYSIS {
190             event_signal_thread_locked(&log->event);
192             event_signal(&log->event, false);
210     dlog_t* log = rdr->log;
214     spin_lock_irqsave(&log->lock, state);
218     // If the read-tail is not within the range of log-tail..log-head
220     // to the current log-tail.
222     if ((log->head - log->tail) < (log->head - rtail)) {
223         rtail = log->tail;
226     if (rtail != log->head) {
228         uint32_t header = *reinterpret_cast<uint32_t*>(log->data + offset);
234             memcpy(ptr, log->data + offset, actual);
236             memcpy(ptr, log->data + offset, fifospace);
237             memcpy(ptr + fifospace, log->data, actual - fifospace);
248     spin_unlock_irqrestore(&log->lock, state);
254     dlog_t* log = &DLOG;
256     rdr->log = log;
260     mutex_acquire(&log->readers_lock);
261     list_add_tail(&log->readers, &rdr->node);
266     spin_lock_irqsave(&log->lock, state);
267     rdr->tail = log->tail;
268     do_notify = (log->tail != log->head);
269     spin_unlock_irqrestore(&log->lock, state);
277     mutex_release(&log->readers_lock);
281     dlog_t* log = rdr->log;
283     mutex_acquire(&log->readers_lock);
285     mutex_release(&log->readers_lock);
290 // have one so they can process new log messages.
292     dlog_t* log = &DLOG;
298         event_wait(&log->event);
300         // notify readers that new log items were posted
301         mutex_acquire(&log->readers_lock);
303         list_for_every_entry (&log->readers, rdr, dlog_reader_t, node) {
308         mutex_release(&log->readers_lock);
342     // assembly buffer with room for log text plus header text
384     // if we're panicing, stop processing log writes
390     // replay debug log?
414     // responsible for passing log records to the dumper.