1/*
2 * Copyright 2015 LabWare
3 * Copyright 2014 Google, Inc.
4 * Copyright (c) 2002-2005 The Regents of The University of Michigan
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are

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149
150static const char GDBStart = '$';
151static const char GDBEnd = '#';
152static const char GDBGoodP = '+';
153static const char GDBBadP = '-';
154
155static const int GDBPacketBufLen = 1024;
156
157#ifndef NDEBUG
158vector<BaseRemoteGDB *> debuggers;
159
160void
161debugger()
162{
163 static int current_debugger = -1;
164 if (current_debugger >= 0 && current_debugger < (int)debuggers.size()) {
165 BaseRemoteGDB *gdb = debuggers[current_debugger];
166 if (!gdb->isattached())
167 gdb->listener->accept();
168 if (gdb->isattached())
169 gdb->trap(SIGILL);
170 }
171}
172#endif
173
174///////////////////////////////////////////////////////////
175//
176//
177//
178
179GDBListener::InputEvent::InputEvent(GDBListener *l, int fd, int e)
180 : PollEvent(fd, e), listener(l)
181{}
182
183void
184GDBListener::InputEvent::process(int revent)
185{
186 listener->accept();
187}
188
189GDBListener::GDBListener(BaseRemoteGDB *g, int p)
190 : inputEvent(NULL), gdb(g), port(p)
191{
192 assert(!gdb->listener);
193 gdb->listener = this;
194}
195
196GDBListener::~GDBListener()
197{
198 delete inputEvent;
199}
200
201string
202GDBListener::name()
203{
204 return gdb->name() + ".listener";
205}
206
207void
208GDBListener::listen()
209{
210 if (ListenSocket::allDisabled()) {
211 warn_once("Sockets disabled, not accepting gdb connections");
212 return;
213 }
214
215 while (!listener.listen(port, true)) {
216 DPRINTF(GDBMisc, "Can't bind port %d\n", port);
217 port++;
218 }
219
220 inputEvent = new InputEvent(this, listener.getfd(), POLLIN);
221 pollQueue.schedule(inputEvent);
222
223#ifndef NDEBUG
224 gdb->number = debuggers.size();
225 debuggers.push_back(gdb);
226#endif
227
228#ifndef NDEBUG
229 ccprintf(cerr, "%d: %s: listening for remote gdb #%d on port %d\n",
230 curTick(), name(), gdb->number, port);
231#else
232 ccprintf(cerr, "%d: %s: listening for remote gdb on port %d\n",
233 curTick(), name(), port);
234#endif
235}
236
237void
238GDBListener::accept()
239{
240 if (!listener.islistening())
241 panic("GDBListener::accept(): cannot accept if we're not listening!");
242
243 int sfd = listener.accept(true);
244
245 if (sfd != -1) {
246 if (gdb->isattached())
247 close(sfd);
248 else
249 gdb->attach(sfd);
250 }
251}
252
253int
254GDBListener::getPort() const
255{
256 panic_if(!listener.islistening(),
257 "Remote GDB port is unknown until GDBListener::listen() has "
258 "been called.\n");
259
260 return port;
261}
262
263BaseRemoteGDB::InputEvent::InputEvent(BaseRemoteGDB *g, int fd, int e)
264 : PollEvent(fd, e), gdb(g)
265{}
266
267void
268BaseRemoteGDB::InputEvent::process(int revent)
269{
270 if (gdb->trapEvent.scheduled()) {
271 warn("GDB trap event has already been scheduled! "
272 "Ignoring this input event.");
273 return;
274 }
275
276 if (revent & POLLIN) {
277 gdb->trapEvent.type(SIGILL);
278 gdb->scheduleInstCommitEvent(&gdb->trapEvent, 0);
279 } else if (revent & POLLNVAL) {
280 gdb->descheduleInstCommitEvent(&gdb->trapEvent);
281 gdb->detach();
282 }
283}
284
285void
286BaseRemoteGDB::TrapEvent::process()
287{
288 gdb->trap(_type);
289}
290
291void
292BaseRemoteGDB::processSingleStepEvent()
293{
294 if (!singleStepEvent.scheduled())
295 scheduleInstCommitEvent(&singleStepEvent, 1);
296 trap(SIGTRAP);
297}
298
299BaseRemoteGDB::BaseRemoteGDB(System *_system, ThreadContext *c) :
300 inputEvent(NULL), trapEvent(this), listener(NULL), number(-1),
301 fd(-1), active(false), attached(false), system(_system),
302 context(c),
303 singleStepEvent([this]{ processSingleStepEvent(); }, name())
304{
305}
306
307BaseRemoteGDB::~BaseRemoteGDB()
308{
309 if (inputEvent)
310 delete inputEvent;
311}
312
313string
314BaseRemoteGDB::name()
315{
316 return system->name() + ".remote_gdb";
317}
318
319bool
320BaseRemoteGDB::isattached()
321{ return attached; }
322
323void
324BaseRemoteGDB::attach(int f)
325{
326 fd = f;
327
328 inputEvent = new InputEvent(this, fd, POLLIN);
329 pollQueue.schedule(inputEvent);
330
331 attached = true;
332 DPRINTFN("remote gdb attached\n");
333}
334
335void
336BaseRemoteGDB::detach()
337{
338 attached = false;
339 active = false;
340 clearSingleStep();
341 close(fd);
342 fd = -1;
343
344 pollQueue.remove(inputEvent);
345 DPRINTFN("remote gdb detached\n");
346}
347
348/////////////////////////
349//
350//
351
352uint8_t
353BaseRemoteGDB::getbyte()
354{
355 uint8_t b;
356 if (::read(fd, &b, sizeof(b)) == sizeof(b))
357 return b;
358
359 throw BadClient("Couldn't read data from debugger.");
360}
361
362void
363BaseRemoteGDB::putbyte(uint8_t b)
364{
365 if (::write(fd, &b, sizeof(b)) == sizeof(b))
366 return;
367
368 throw BadClient("Couldn't write data to the debugger.");
369}
370
371// Send a packet to gdb
372void
373BaseRemoteGDB::send(const char *bp)
374{
375 const char *p;
376 uint8_t csum, c;
377
378 DPRINTF(GDBSend, "send: %s\n", bp);
379
380 do {
381 p = bp;
382 // Start sending a packet
383 putbyte(GDBStart);
384 // Send the contents, and also keep a check sum.
385 for (csum = 0; (c = *p); p++) {
386 putbyte(c);
387 csum += c;
388 }
389 // Send the ending character.
390 putbyte(GDBEnd);
391 // Send the checksum.
392 putbyte(i2digit(csum >> 4));
393 putbyte(i2digit(csum));
394 // Try transmitting over and over again until the other end doesn't
395 // send an error back.
396 c = getbyte();
397 } while ((c & 0x7f) == GDBBadP);
398}
399
400// Receive a packet from gdb
401int
402BaseRemoteGDB::recv(char *bp, int maxlen)
403{
404 char *p;
405 uint8_t c;
406 int csum;
407 int len;

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455 putbyte(GDBBadP);
456 } while (1);
457
458 DPRINTF(GDBRecv, "recv: %s\n", bp);
459
460 return len;
461}
462
463// Read bytes from kernel address space for debugger.
464bool
465BaseRemoteGDB::read(Addr vaddr, size_t size, char *data)
466{
467 static Addr lastaddr = 0;
468 static size_t lastsize = 0;
469
470 if (vaddr < 10) {
471 DPRINTF(GDBRead, "read: reading memory location zero!\n");
472 vaddr = lastaddr + lastsize;
473 }
474
475 DPRINTF(GDBRead, "read: addr=%#x, size=%d", vaddr, size);
476
477 if (FullSystem) {
478 FSTranslatingPortProxy &proxy = context->getVirtProxy();
479 proxy.readBlob(vaddr, (uint8_t*)data, size);
480 } else {
481 SETranslatingPortProxy &proxy = context->getMemProxy();
482 proxy.readBlob(vaddr, (uint8_t*)data, size);
483 }
484
485#if TRACING_ON
486 if (DTRACE(GDBRead)) {
487 if (DTRACE(GDBExtra)) {
488 char buf[1024];
489 mem2hex(buf, data, size);

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513 if (DTRACE(GDBExtra)) {
514 char buf[1024];
515 mem2hex(buf, data, size);
516 DPRINTFNR(": %s\n", buf);
517 } else
518 DPRINTFNR("\n");
519 }
520 if (FullSystem) {
521 FSTranslatingPortProxy &proxy = context->getVirtProxy();
522 proxy.writeBlob(vaddr, (uint8_t*)data, size);
523 } else {
524 SETranslatingPortProxy &proxy = context->getMemProxy();
525 proxy.writeBlob(vaddr, (uint8_t*)data, size);
526 }
527
528 return true;
529}
530
531void
532BaseRemoteGDB::clearSingleStep()
533{
534 descheduleInstCommitEvent(&singleStepEvent);
535}
536
537void
538BaseRemoteGDB::setSingleStep()
539{
540 if (!singleStepEvent.scheduled())
541 scheduleInstCommitEvent(&singleStepEvent, 1);
542}
543
544PCEventQueue *BaseRemoteGDB::getPcEventQueue()
545{
546 return &system->pcEventQueue;
547}
548
549EventQueue *
550BaseRemoteGDB::getComInstEventQueue()
551{
552 BaseCPU *cpu = context->getCpuPtr();
553 return cpu->comInstEventQueue[context->threadId()];
554}
555
556void
557BaseRemoteGDB::scheduleInstCommitEvent(Event *ev, int delta)
558{
559 EventQueue *eq = getComInstEventQueue();
560 // Here "ticks" aren't simulator ticks which measure time, they're
561 // instructions committed by the CPU.
562 eq->schedule(ev, eq->getCurTick() + delta);
563}
564
565void
566BaseRemoteGDB::descheduleInstCommitEvent(Event *ev)
567{
568 if (ev->scheduled())
569 getComInstEventQueue()->deschedule(ev);
570}
571
572bool
573BaseRemoteGDB::checkBpLen(size_t len)
574{
575 return len == sizeof(MachInst);
576}
577
578BaseRemoteGDB::HardBreakpoint::HardBreakpoint(BaseRemoteGDB *_gdb, Addr pc)
579 : PCEvent(_gdb->getPcEventQueue(), "HardBreakpoint Event", pc),
580 gdb(_gdb), refcount(0)
581{
582 DPRINTF(GDBMisc, "creating hardware breakpoint at %#x\n", evpc);
583}
584
585void
586BaseRemoteGDB::HardBreakpoint::process(ThreadContext *tc)
587{
588 DPRINTF(GDBMisc, "handling hardware breakpoint at %#x\n", pc());
589
590 if (tc == gdb->context)
591 gdb->trap(SIGTRAP);
592}
593
594void
595BaseRemoteGDB::insertSoftBreak(Addr addr, size_t len)
596{
597 if (!checkBpLen(len))
598 throw BadClient("Invalid breakpoint length\n");
599
600 return insertHardBreak(addr, len);
601}
602

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614{
615 if (!checkBpLen(len))
616 throw BadClient("Invalid breakpoint length\n");
617
618 DPRINTF(GDBMisc, "Inserting hardware breakpoint at %#x\n", addr);
619
620 HardBreakpoint *&bkpt = hardBreakMap[addr];
621 if (bkpt == 0)
622 bkpt = new HardBreakpoint(this, addr);
623
624 bkpt->refcount++;
625}
626
627void
628BaseRemoteGDB::removeHardBreak(Addr addr, size_t len)
629{
630 if (!checkBpLen(len))
631 throw BadClient("Invalid breakpoint length\n");
632
633 DPRINTF(GDBMisc, "Removing hardware breakpoint at %#x\n", addr);
634
635 break_iter_t i = hardBreakMap.find(addr);
636 if (i == hardBreakMap.end())
637 throw CmdError("E0C");
638
639 HardBreakpoint *hbp = (*i).second;
640 if (--hbp->refcount == 0) {
641 delete hbp;
642 hardBreakMap.erase(i);
643 }
644}
645
646void
647BaseRemoteGDB::setTempBreakpoint(Addr bkpt)
648{
649 DPRINTF(GDBMisc, "setTempBreakpoint: addr=%#x\n", bkpt);
650 insertHardBreak(bkpt, sizeof(TheISA::MachInst));
651}
652
653void
654BaseRemoteGDB::clearTempBreakpoint(Addr &bkpt)
655{
656 DPRINTF(GDBMisc, "setTempBreakpoint: addr=%#x\n", bkpt);
657 removeHardBreak(bkpt, sizeof(TheISA::MachInst));
658 bkpt = 0;
659}
660
661enum GdbBreakpointType {
662 GdbSoftBp = '0',
663 GdbHardBp = '1',
664 GdbWriteWp = '2',
665 GdbReadWp = '3',
666 GdbAccWp = '4',
667};
668
669const char *
670BaseRemoteGDB::break_type(char c)
671{
672 switch(c) {
673 case GdbSoftBp: return "software breakpoint";
674 case GdbHardBp: return "hardware breakpoint";
675 case GdbWriteWp: return "write watchpoint";
676 case GdbReadWp: return "read watchpoint";
677 case GdbAccWp: return "access watchpoint";
678 default: return "unknown breakpoint/watchpoint";
679 }
680}
681
682std::map BaseRemoteGDB::command_map = {
683 // last signal
684 { '?', { "KGDB_SIGNAL", &BaseRemoteGDB::cmd_signal } },
685 // set baud (deprecated)
686 { 'b', { "KGDB_SET_BAUD", &BaseRemoteGDB::cmd_unsupported } },
687 // set breakpoint (deprecated)
688 { 'B', { "KGDB_SET_BREAK", &BaseRemoteGDB::cmd_unsupported } },
689 // resume
690 { 'c', { "KGDB_CONT", &BaseRemoteGDB::cmd_cont } },

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731 // write memory
732 { 'X', { "KGDB_BINARY_DLOAD", &BaseRemoteGDB::cmd_unsupported } },
733 // remove breakpoint or watchpoint
734 { 'z', { "KGDB_CLR_HW_BKPT", &BaseRemoteGDB::cmd_clr_hw_bkpt } },
735 // insert breakpoint or watchpoint
736 { 'Z', { "KGDB_SET_HW_BKPT", &BaseRemoteGDB::cmd_set_hw_bkpt } },
737};
738
739
740bool
741BaseRemoteGDB::cmd_unsupported(GdbCommand::Context &ctx)
742{
743 DPRINTF(GDBMisc, "Unsupported command: %s\n", ctx.cmd->name);
744 DDUMP(GDBMisc, ctx.data, ctx.len);
745 throw Unsupported();
746}

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754}
755
756bool
757BaseRemoteGDB::cmd_cont(GdbCommand::Context &ctx)
758{
759 const char *p = ctx.data;
760 if (ctx.len) {
761 Addr newPc = hex2i(&p);
762 context->pcState(newPc);
763 }
764 clearSingleStep();
765 return false;
766}
767
768bool
769BaseRemoteGDB::cmd_async_cont(GdbCommand::Context &ctx)
770{
771 const char *p = ctx.data;
772 hex2i(&p);
773 if (*p++ == ';') {
774 Addr newPc = hex2i(&p);
775 context->pcState(newPc);
776 }
777 clearSingleStep();
778 return false;
779}
780
781bool
782BaseRemoteGDB::cmd_detach(GdbCommand::Context &ctx)
783{

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798bool
799BaseRemoteGDB::cmd_reg_w(GdbCommand::Context &ctx)
800{
801 const char *p = ctx.data;
802 p = hex2mem(regCachePtr->data(), p, regCachePtr->size());
803 if (p == NULL || *p != '\0')
804 throw CmdError("E01");
805
806 regCachePtr->setRegs(context);
807 send("OK");
808
809 return true;
810}
811
812bool
813BaseRemoteGDB::cmd_set_thread(GdbCommand::Context &ctx)
814{

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878
879bool
880BaseRemoteGDB::cmd_async_step(GdbCommand::Context &ctx)
881{
882 const char *p = ctx.data;
883 hex2i(&p); // Ignore the subcommand byte.
884 if (*p++ == ';') {
885 Addr newPc = hex2i(&p);
886 context->pcState(newPc);
887 }
888 setSingleStep();
889 return false;
890}
891
892bool
893BaseRemoteGDB::cmd_step(GdbCommand::Context &ctx)
894{
895 if (ctx.len) {
896 const char *p = ctx.data;
897 Addr newPc = hex2i(&p);
898 context->pcState(newPc);
899 }
900 setSingleStep();
901 return false;
902}
903
904bool
905BaseRemoteGDB::cmd_clr_hw_bkpt(GdbCommand::Context &ctx)
906{

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961 case GdbAccWp:
962 default: // unknown
963 throw Unsupported();
964 }
965 send("OK");
966
967 return true;
968}
969
970
971// This function does all command processing for interfacing to a
972// remote gdb. Note that the error codes are ignored by gdb at
973// present, but might eventually become meaningful. (XXX) It might
974// makes sense to use POSIX errno values, because that is what the
975// gdb/remote.c functions want to return.
976bool
977BaseRemoteGDB::trap(int type)
978{
979
980 if (!attached)
981 return false;
982
983 DPRINTF(GDBMisc, "trap: PC=%s\n", context->pcState());
984
985 clearSingleStep();
986
987 /*
988 * The first entry to this function is normally through
989 * a breakpoint trap in kgdb_connect(), in which case we
990 * must advance past the breakpoint because gdb will not.
991 *
992 * On the first entry here, we expect that gdb is not yet
993 * listening to us, so just enter the interaction loop.
994 * After the debugger is "active" (connected) it will be
995 * waiting for a "signaled" message from us.
996 */
997 if (!active) {
998 active = true;
999 } else {
1000 // Tell remote host that an exception has occurred.
1001 send(csprintf("S%02x", type).c_str());
1002 }
1003
1004 // Stick frame regs into our reg cache.
1005 regCachePtr = gdbRegs();
1006 regCachePtr->getRegs(context);
1007
1008 char data[GDBPacketBufLen + 1];
1009 GdbCommand::Context cmdCtx;
1010 cmdCtx.type = type;
1011 cmdCtx.data = &data[1];
1012
1013 for (;;) {
1014 try {
1015 size_t datalen = recv(data, sizeof(data));
1016 if (datalen < 1)
1017 throw BadClient();
1018
1019 data[datalen] = 0; // Sentinel
1020 cmdCtx.cmd_byte = data[0];
1021 cmdCtx.len = datalen - 1;
1022
1023 auto cmdIt = command_map.find(cmdCtx.cmd_byte);
1024 if (cmdIt == command_map.end()) {
1025 DPRINTF(GDBMisc, "Unknown command: %c(%#x)\n",
1026 cmdCtx.cmd_byte, cmdCtx.cmd_byte);
1027 throw Unsupported();
1028 }
1029 cmdCtx.cmd = &(cmdIt->second);
1030
1031 if (!(this->*(cmdCtx.cmd->func))(cmdCtx))
1032 break;
1033
1034 } catch (BadClient &e) {
1035 if (e.warning)
1036 warn(e.warning);
1037 detach();
1038 break;
1039 } catch (Unsupported &e) {
1040 send("");
1041 } catch (CmdError &e) {
1042 send(e.error.c_str());
1043 } catch (...) {
1044 panic("Unrecognzied GDB exception.");
1045 }
1046 }
1047
1048 return true;
1049}
1050
1051// Convert a hex digit into an integer.
1052// This returns -1 if the argument passed is no valid hex digit.
1053int
1054BaseRemoteGDB::digit2i(char c)
1055{
1056 if (c >= '0' && c <= '9')
1057 return (c - '0');
1058 else if (c >= 'a' && c <= 'f')
1059 return (c - 'a' + 10);
1060 else if (c >= 'A' && c <= 'F')
1061 return (c - 'A' + 10);
1062 else
1063 return (-1);
1064}
1065
1066// Convert the low 4 bits of an integer into an hex digit.
1067char
1068BaseRemoteGDB::i2digit(int n)
1069{
1070 return ("0123456789abcdef"[n & 0x0f]);
1071}
1072
1073// Convert a byte array into an hex string.
1074void
1075BaseRemoteGDB::mem2hex(char *vdst, const char *vsrc, int len)
1076{
1077 char *dst = vdst;
1078 const char *src = vsrc;
1079
1080 while (len--) {
1081 *dst++ = i2digit(*src >> 4);
1082 *dst++ = i2digit(*src++);
1083 }
1084 *dst = '\0';
1085}
1086
1087// Convert an hex string into a byte array.
1088// This returns a pointer to the character following the last valid
1089// hex digit. If the string ends in the middle of a byte, NULL is
1090// returned.
1091const char *
1092BaseRemoteGDB::hex2mem(char *vdst, const char *src, int maxlen)
1093{
1094 char *dst = vdst;
1095 int msb, lsb;
1096
1097 while (*src && maxlen--) {
1098 msb = digit2i(*src++);
1099 if (msb < 0)
1100 return (src - 1);
1101 lsb = digit2i(*src++);
1102 if (lsb < 0)
1103 return (NULL);
1104 *dst++ = (msb << 4) | lsb;
1105 }
1106 return src;
1107}
1108
1109// Convert an hex string into an integer.
1110// This returns a pointer to the character following the last valid
1111// hex digit.
1112Addr
1113BaseRemoteGDB::hex2i(const char **srcp)
1114{
1115 const char *src = *srcp;
1116 Addr r = 0;
1117 int nibble;
1118
1119 while ((nibble = digit2i(*src)) >= 0) {
1120 r *= 16;
1121 r += nibble;
1122 src++;
1123 }
1124 *srcp = src;
1125 return r;
1126}