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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142#include "mem/port.hh"
143#include "mem/se_translating_port_proxy.hh"
144#include "sim/full_system.hh"
145#include "sim/system.hh"
146
147using namespace std;
148using namespace TheISA;
149
150#ifndef NDEBUG
151vector<BaseRemoteGDB *> debuggers;
152
153void
154debugger()
155{
156 static int current_debugger = -1;
157 if (current_debugger >= 0 && current_debugger < (int)debuggers.size()) {

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183 : inputEvent(NULL), gdb(g), port(p)
184{
185 assert(!gdb->listener);
186 gdb->listener = this;
187}
188
189GDBListener::~GDBListener()
190{
191 if (inputEvent)
192 delete inputEvent;
193}
194
195string
196GDBListener::name()
197{
198 return gdb->name() + ".listener";
199}
200

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314 attached = true;
315 DPRINTFN("remote gdb attached\n");
316}
317
318void
319BaseRemoteGDB::detach()
320{
321 attached = false;
322 close(fd);
323 fd = -1;
324
325 pollQueue.remove(inputEvent);
326 DPRINTFN("remote gdb detached\n");
327}
328
329const char *
330BaseRemoteGDB::gdb_command(char cmd)
331{
332 switch (cmd) {
333 case GDBSignal: return "KGDB_SIGNAL";
334 case GDBSetBaud: return "KGDB_SET_BAUD";
335 case GDBSetBreak: return "KGDB_SET_BREAK";
336 case GDBCont: return "KGDB_CONT";
337 case GDBAsyncCont: return "KGDB_ASYNC_CONT";
338 case GDBDebug: return "KGDB_DEBUG";
339 case GDBDetach: return "KGDB_DETACH";
340 case GDBRegR: return "KGDB_REG_R";
341 case GDBRegW: return "KGDB_REG_W";
342 case GDBSetThread: return "KGDB_SET_THREAD";
343 case GDBCycleStep: return "KGDB_CYCLE_STEP";
344 case GDBSigCycleStep: return "KGDB_SIG_CYCLE_STEP";
345 case GDBKill: return "KGDB_KILL";
346 case GDBMemW: return "KGDB_MEM_W";
347 case GDBMemR: return "KGDB_MEM_R";
348 case GDBSetReg: return "KGDB_SET_REG";
349 case GDBReadReg: return "KGDB_READ_REG";
350 case GDBQueryVar: return "KGDB_QUERY_VAR";
351 case GDBSetVar: return "KGDB_SET_VAR";
352 case GDBReset: return "KGDB_RESET";
353 case GDBStep: return "KGDB_STEP";
354 case GDBAsyncStep: return "KGDB_ASYNC_STEP";
355 case GDBThreadAlive: return "KGDB_THREAD_ALIVE";
356 case GDBTargetExit: return "KGDB_TARGET_EXIT";
357 case GDBBinaryDload: return "KGDB_BINARY_DLOAD";
358 case GDBClrHwBkpt: return "KGDB_CLR_HW_BKPT";
359 case GDBSetHwBkpt: return "KGDB_SET_HW_BKPT";
360 case GDBStart: return "KGDB_START";
361 case GDBEnd: return "KGDB_END";
362 case GDBGoodP: return "KGDB_GOODP";
363 case GDBBadP: return "KGDB_BADP";
364 default: return "KGDB_UNKNOWN";
365 }
366}
367
368/////////////////////////
369//
370//
371
372bool
373BaseRemoteGDB::getbyte(uint8_t &b)
374{
375 if (::read(fd, &b, sizeof(b)) == sizeof(b)) {
376 return true;
377 } else {
378 warn("Couldn't read data from debugger, detaching.");
379 detach();
380 return false;
381 }
382}
383
384bool
385BaseRemoteGDB::putbyte(uint8_t b)
386{
387 if (::write(fd, &b, sizeof(b)) == sizeof(b)) {
388 return true;
389 } else {
390 warn("Couldn't write data to the debugger, detaching.");
391 detach();
392 return false;
393 }
394}
395
396// Send a packet to gdb
397ssize_t
398BaseRemoteGDB::send(const char *bp)
399{
400 const char *p;
401 uint8_t csum, c;
402
403 DPRINTF(GDBSend, "send: %s\n", bp);
404
405 do {
406 p = bp;
407 //Start sending a packet
408 if (!putbyte(GDBStart))
409 return -1;
410 //Send the contents, and also keep a check sum.
411 for (csum = 0; (c = *p); p++) {
412 if (!putbyte(c))
413 return -1;
414 csum += c;
415 }
416 if (//Send the ending character.
417 !putbyte(GDBEnd) ||
418 //Sent the checksum.
419 !putbyte(i2digit(csum >> 4)) ||
420 !putbyte(i2digit(csum))) {
421 return -1;
422 }
423 //Try transmitting over and over again until the other end doesn't
424 //send an error back.
425 if (!getbyte(c))
426 return -1;
427 } while ((c & 0x7f) == GDBBadP);
428 return 0;
429}
430
431// Receive a packet from gdb
432int
433BaseRemoteGDB::recv(char *bp, int maxlen)
434{
435 char *p;
436 uint8_t c;
437 int csum;
438 int len;
439
440 do {
441 p = bp;
442 csum = len = 0;
443 //Find the beginning of a packet
444 do {
445 if (!getbyte(c))
446 return -1;
447 } while (c != GDBStart);
448
449 //Read until you find the end of the data in the packet, and keep
450 //track of the check sum.
451 while (len < maxlen) {
452 if (!getbyte(c))
453 return -1;
454 if (c == GDBEnd)
455 break;
456 c &= 0x7f;
457 csum += c;
458 *p++ = c;
459 len++;
460 }
461
462 //Mask the check sum, and terminate the command string.
463 csum &= 0xff;
464 *p = '\0';
465
466 //If the command was too long, report an error.
467 if (len >= maxlen) {
468 if (!putbyte(GDBBadP))
469 return -1;
470 continue;
471 }
472
473 //Bring in the checksum. If the check sum matches, csum will be 0.
474 uint8_t csum1, csum2;
475 if (!getbyte(csum1) || !getbyte(csum2))
476 return -1;
477 csum -= digit2i(csum1) * 16;
478 csum -= digit2i(csum2);
479
480 //If the check sum was correct
481 if (csum == 0) {
482 //Report that the packet was received correctly
483 if (!putbyte(GDBGoodP))
484 return -1;
485 // Sequence present?
486 if (bp[2] == ':') {
487 if (!putbyte(bp[0]) || !putbyte(bp[1]))
488 return -1;
489 len -= 3;
490 memcpy(bp, bp+3, len);
491 }
492 break;
493 }
494 //Otherwise, report that there was a mistake.
495 if (!putbyte(GDBBadP))
496 return -1;
497 } while (1);
498
499 DPRINTF(GDBRecv, "recv: %s: %s\n", gdb_command(*bp), bp);
500
501 return (len);
502}
503
504// Read bytes from kernel address space for debugger.
505bool
506BaseRemoteGDB::read(Addr vaddr, size_t size, char *data)
507{
508 static Addr lastaddr = 0;
509 static size_t lastsize = 0;

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627BaseRemoteGDB::HardBreakpoint::process(ThreadContext *tc)
628{
629 DPRINTF(GDBMisc, "handling hardware breakpoint at %#x\n", pc());
630
631 if (tc == gdb->context)
632 gdb->trap(SIGTRAP);
633}
634
635bool
636BaseRemoteGDB::insertSoftBreak(Addr addr, size_t len)
637{
638 if (!checkBpLen(len))
639 panic("invalid length\n");
640
641 return insertHardBreak(addr, len);
642}
643
644bool
645BaseRemoteGDB::removeSoftBreak(Addr addr, size_t len)
646{
647 if (!checkBpLen(len))
648 panic("invalid length\n");
649
650 return removeHardBreak(addr, len);
651}
652
653bool
654BaseRemoteGDB::insertHardBreak(Addr addr, size_t len)
655{
656 if (!checkBpLen(len))
657 panic("invalid length\n");
658
659 DPRINTF(GDBMisc, "inserting hardware breakpoint at %#x\n", addr);
660
661 HardBreakpoint *&bkpt = hardBreakMap[addr];
662 if (bkpt == 0)
663 bkpt = new HardBreakpoint(this, addr);
664
665 bkpt->refcount++;
666
667 return true;
668}
669
670bool
671BaseRemoteGDB::removeHardBreak(Addr addr, size_t len)
672{
673 if (!checkBpLen(len))
674 panic("invalid length\n");
675
676 DPRINTF(GDBMisc, "removing hardware breakpoint at %#x\n", addr);
677
678 break_iter_t i = hardBreakMap.find(addr);
679 if (i == hardBreakMap.end())
680 return false;
681
682 HardBreakpoint *hbp = (*i).second;
683 if (--hbp->refcount == 0) {
684 delete hbp;
685 hardBreakMap.erase(i);
686 }
687
688 return true;
689}
690
691void
692BaseRemoteGDB::setTempBreakpoint(Addr bkpt)
693{
694 DPRINTF(GDBMisc, "setTempBreakpoint: addr=%#x\n", bkpt);
695 insertHardBreak(bkpt, sizeof(TheISA::MachInst));
696}
697
698void
699BaseRemoteGDB::clearTempBreakpoint(Addr &bkpt)
700{
701 DPRINTF(GDBMisc, "setTempBreakpoint: addr=%#x\n", bkpt);
702 removeHardBreak(bkpt, sizeof(TheISA::MachInst));
703 bkpt = 0;
704}
705
706const char *
707BaseRemoteGDB::break_type(char c)
708{
709 switch(c) {
710 case '0': return "software breakpoint";
711 case '1': return "hardware breakpoint";
712 case '2': return "write watchpoint";
713 case '3': return "read watchpoint";
714 case '4': return "access watchpoint";
715 default: return "unknown breakpoint/watchpoint";
716 }
717}
718
719// This function does all command processing for interfacing to a
720// remote gdb. Note that the error codes are ignored by gdb at
721// present, but might eventually become meaningful. (XXX) It might
722// makes sense to use POSIX errno values, because that is what the
723// gdb/remote.c functions want to return.
724bool
725BaseRemoteGDB::trap(int type)
726{
727 uint64_t val;
728 size_t datalen, len;
729 char data[GDBPacketBufLen + 1];
730 size_t bufferSize;
731 const char *p;
732 char command, subcmd;
733 string var;
734 bool ret;
735
736 if (!attached)
737 return false;
738
739 unique_ptr<BaseRemoteGDB::BaseGdbRegCache> regCache(gdbRegs());
740
741 bufferSize = regCache->size() * 2 + 256;
742 unique_ptr<char[]> buffer_mem(new char[bufferSize]);
743 char *buffer = buffer_mem.get();
744
745 DPRINTF(GDBMisc, "trap: PC=%s\n", context->pcState());
746
747 clearSingleStep();
748
749 /*
750 * The first entry to this function is normally through
751 * a breakpoint trap in kgdb_connect(), in which case we
752 * must advance past the breakpoint because gdb will not.
753 *
754 * On the first entry here, we expect that gdb is not yet
755 * listening to us, so just enter the interaction loop.
756 * After the debugger is "active" (connected) it will be
757 * waiting for a "signaled" message from us.
758 */
759 if (!active) {
760 active = true;
761 } else {
762 // Tell remote host that an exception has occurred.
763 snprintf(buffer, bufferSize, "S%02x", type);
764 if (send(buffer) < 0)
765 return true;
766 }
767
768 // Stick frame regs into our reg cache.
769 regCache->getRegs(context);
770
771 for (;;) {
772 int recved = recv(data, sizeof(data));
773 if (recved < 0)
774 return true;
775 datalen = recved;
776 data[sizeof(data) - 1] = 0; // Sentinel
777 command = data[0];
778 subcmd = 0;
779 p = data + 1;
780 switch (command) {
781
782 case GDBSignal:
783 // if this command came from a running gdb, answer it --
784 // the other guy has no way of knowing if we're in or out
785 // of this loop when he issues a "remote-signal".
786 snprintf(buffer, bufferSize,
787 "S%02x", type);
788 if (send(buffer) < 0)
789 return true;
790 continue;
791
792 case GDBRegR:
793 if (2 * regCache->size() > bufferSize)
794 panic("buffer too small");
795
796 mem2hex(buffer, regCache->data(), regCache->size());
797 if (send(buffer) < 0)
798 return true;
799 continue;
800
801 case GDBRegW:
802 p = hex2mem(regCache->data(), p, regCache->size());
803 if (p == NULL || *p != '\0') {
804 if (send("E01") < 0)
805 return true;
806 } else {
807 regCache->setRegs(context);
808 if (send("OK") < 0)
809 return true;
810 }
811 continue;
812
813 case GDBMemR:
814 val = hex2i(&p);
815 if (*p++ != ',') {
816 if (send("E02") < 0)
817 return true;
818 continue;
819 }
820 len = hex2i(&p);
821 if (*p != '\0') {
822 if (send("E03") < 0)
823 return true;
824 continue;
825 }
826 if (len > bufferSize) {
827 if (send("E04") < 0)
828 return true;
829 continue;
830 }
831 if (!acc(val, len)) {
832 if (send("E05") < 0)
833 return true;
834 continue;
835 }
836
837 if (read(val, (size_t)len, buffer)) {
838 // variable length array would be nice, but C++ doesn't
839 // officially support those...
840 char *temp = new char[2*len+1];
841 mem2hex(temp, buffer, len);
842 if (send(temp) < 0) {
843 delete [] temp;
844 return true;
845 }
846 delete [] temp;
847 } else {
848 if (send("E05") < 0)
849 return true;
850 }
851 continue;
852
853 case GDBMemW:
854 val = hex2i(&p);
855 if (*p++ != ',') {
856 if (send("E06") < 0)
857 return true;
858 continue;
859 }
860 len = hex2i(&p);
861 if (*p++ != ':') {
862 if (send("E07") < 0)
863 return true;
864 continue;
865 }
866 if (len > datalen - (p - data)) {
867 if (send("E08") < 0)
868 return true;
869 continue;
870 }
871 p = hex2mem(buffer, p, bufferSize);
872 if (p == NULL) {
873 if (send("E09") < 0)
874 return true;
875 continue;
876 }
877 if (!acc(val, len)) {
878 if (send("E0A") < 0)
879 return true;
880 continue;
881 }
882 if (write(val, (size_t)len, buffer)) {
883 if (send("OK") < 0)
884 return true;
885 } else {
886 if (send("E0B") < 0)
887 return true;
888 }
889 continue;
890
891 case GDBSetThread:
892 subcmd = *p++;
893 val = hex2i(&p);
894 if (val == 0) {
895 if (send("OK") < 0)
896 return true;
897 } else {
898 if (send("E01") < 0)
899 return true;
900 }
901 continue;
902
903 case GDBDetach:
904 case GDBKill:
905 active = false;
906 clearSingleStep();
907 detach();
908 return true;
909
910 case GDBAsyncCont:
911 subcmd = hex2i(&p);
912 if (*p++ == ';') {
913 val = hex2i(&p);
914 context->pcState(val);
915 }
916 clearSingleStep();
917 return true;
918
919 case GDBCont:
920 if (p - data < (ptrdiff_t)datalen) {
921 val = hex2i(&p);
922 context->pcState(val);
923 }
924 clearSingleStep();
925 return true;
926
927 case GDBAsyncStep:
928 subcmd = hex2i(&p);
929 if (*p++ == ';') {
930 val = hex2i(&p);
931 context->pcState(val);
932 }
933 setSingleStep();
934 return true;
935
936 case GDBStep:
937 if (p - data < (ptrdiff_t)datalen) {
938 val = hex2i(&p);
939 context->pcState(val);
940 }
941 setSingleStep();
942 return true;
943
944 case GDBClrHwBkpt:
945 subcmd = *p++;
946 if (*p++ != ',' && send("E0D") < 0)
947 return true;
948 val = hex2i(&p);
949 if (*p++ != ',' && send("E0D") < 0)
950 return true;
951 len = hex2i(&p);
952
953 DPRINTF(GDBMisc, "clear %s, addr=%#x, len=%d\n",
954 break_type(subcmd), val, len);
955
956 ret = false;
957
958 switch (subcmd) {
959 case '0': // software breakpoint
960 ret = removeSoftBreak(val, len);
961 break;
962
963 case '1': // hardware breakpoint
964 ret = removeHardBreak(val, len);
965 break;
966
967 case '2': // write watchpoint
968 case '3': // read watchpoint
969 case '4': // access watchpoint
970 default: // unknown
971 if (send("") < 0)
972 return true;
973 break;
974 }
975
976 if (send(ret ? "OK" : "E0C") < 0)
977 return true;
978 continue;
979
980 case GDBSetHwBkpt:
981 subcmd = *p++;
982 if (*p++ != ',' && send("E0D") < 0)
983 return true;
984 val = hex2i(&p);
985 if (*p++ != ',' && send("E0D") < 0)
986 return true;
987 len = hex2i(&p);
988
989 DPRINTF(GDBMisc, "set %s, addr=%#x, len=%d\n",
990 break_type(subcmd), val, len);
991
992 ret = false;
993
994 switch (subcmd) {
995 case '0': // software breakpoint
996 ret = insertSoftBreak(val, len);
997 break;
998
999 case '1': // hardware breakpoint
1000 ret = insertHardBreak(val, len);
1001 break;
1002
1003 case '2': // write watchpoint
1004 case '3': // read watchpoint
1005 case '4': // access watchpoint
1006 default: // unknown
1007 if (send("") < 0)
1008 return true;
1009 break;
1010 }
1011
1012 if (send(ret ? "OK" : "E0C") < 0)
1013 return true;
1014 continue;
1015
1016 case GDBQueryVar:
1017 var = string(p, datalen - 1);
1018 if (var == "C") {
1019 if (send("QC0") < 0)
1020 return true;
1021 } else {
1022 if (send("") < 0)
1023 return true;
1024 }
1025 continue;
1026
1027 case GDBSetBaud:
1028 case GDBSetBreak:
1029 case GDBDebug:
1030 case GDBCycleStep:
1031 case GDBSigCycleStep:
1032 case GDBReadReg:
1033 case GDBSetVar:
1034 case GDBReset:
1035 case GDBThreadAlive:
1036 case GDBTargetExit:
1037 case GDBBinaryDload:
1038 // Unsupported command
1039 DPRINTF(GDBMisc, "Unsupported command: %s\n",
1040 gdb_command(command));
1041 DDUMP(GDBMisc, (uint8_t *)data, datalen);
1042 if (send("") < 0)
1043 return true;
1044 continue;
1045
1046 default:
1047 // Unknown command.
1048 DPRINTF(GDBMisc, "Unknown command: %c(%#x)\n",
1049 command, command);
1050 if (send("") < 0)
1051 return true;
1052 continue;
1053
1054
1055 }
1056 }
1057
1058 return true;
1059}
1060
1061// Convert a hex digit into an integer.
1062// This returns -1 if the argument passed is no valid hex digit.
1063int
1064BaseRemoteGDB::digit2i(char c)
1065{
1066 if (c >= '0' && c <= '9')
1067 return (c - '0');
1068 else if (c >= 'a' && c <= 'f')
1069 return (c - 'a' + 10);
1070 else if (c >= 'A' && c <= 'F')
1071
1072 return (c - 'A' + 10);
1073 else
1074 return (-1);
1075}
1076
1077// Convert the low 4 bits of an integer into an hex digit.
1078char
1079BaseRemoteGDB::i2digit(int n)

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1109 msb = digit2i(*src++);
1110 if (msb < 0)
1111 return (src - 1);
1112 lsb = digit2i(*src++);
1113 if (lsb < 0)
1114 return (NULL);
1115 *dst++ = (msb << 4) | lsb;
1116 }
1117 return (src);
1118}
1119
1120// Convert an hex string into an integer.
1121// This returns a pointer to the character following the last valid
1122// hex digit.
1123Addr
1124BaseRemoteGDB::hex2i(const char **srcp)
1125{
1126 const char *src = *srcp;
1127 Addr r = 0;
1128 int nibble;
1129
1130 while ((nibble = digit2i(*src)) >= 0) {
1131 r *= 16;
1132 r += nibble;
1133 src++;
1134 }
1135 *srcp = src;
1136 return (r);
1137}
1138