From: KONRAD Frederic <fred.kon...@greensocs.com> This allows gdb to reverse step QEMU: reverse-stepi and reverse-cont commands are allowed.
When step_backward is called, QEMU restores a snapshot before the actual instruction and stops (with a debug exit) when the previous instruction is reached. Signed-off-by: KONRAD Frederic <fred.kon...@greensocs.com> --- gdbstub.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/gdbstub.c b/gdbstub.c index 8afe0b7..99769af 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -33,6 +33,7 @@ #include "sysemu/char.h" #include "sysemu/sysemu.h" #include "exec/gdbstub.h" +#include "reverse-execution.h" #endif #define MAX_PACKET_LENGTH 4096 @@ -1113,6 +1114,17 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf) if (cc->gdb_core_xml_file != NULL) { pstrcat(buf, sizeof(buf), ";qXfer:features:read+"); } + + #ifndef CONFIG_USER_ONLY + /* + * When reverse execution is enabled those additional features must + * be set so GDB allows reverse-stepi and reverse-continue command. + */ + if (cexe_is_enabled()) { + pstrcat(buf, sizeof(buf), ";ReverseStep+;ReverseContinue+"); + } + #endif /* !CONFIG_USER_ONLY */ + put_packet(s, buf); break; } @@ -1161,7 +1173,23 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf) } /* Unrecognised 'q' command. */ goto unknown_command; - + #ifndef CONFIG_USER_ONLY + case 'b': + /* Reverse execution. */ + switch (*p) { + case 's': + cexe_step_backward(s->c_cpu, 1); + break; + case 'c': + cexe_continue_backward(s->c_cpu); + break; + default: + buf[0] = '\0'; + put_packet(s, buf); + break; + } + break; + #endif /* !CONFIG_USER_ONLY */ default: unknown_command: /* put empty packet */ @@ -1221,6 +1249,7 @@ static void gdb_vm_state_change(void *opaque, int running, RunState state) ret = GDB_SIGNAL_TRAP; break; case RUN_STATE_PAUSED: + cexe_stop_reverse_continue(); ret = GDB_SIGNAL_INT; break; case RUN_STATE_SHUTDOWN: -- 1.8.1.4