/*
* This function does all command processing for interfacing to
* a remote gdb. Note that the error codes are ignored by gdb
* at present, but might eventually become meaningful. (XXX)
* It might makes sense to use POSIX errno values, because
* that is what the gdb/remote.c functions want to return.
*/
int
kgdb_trap(int type, db_regs_t *regs)
{
label_t jmpbuf;
vaddr_t addr;
size_t len;
u_char *p;
if (kgdb_dev < 0 || kgdb_getc == NULL) {
/* not debugging */
return (0);
}
/* Detect and recover from unexpected traps. */
if (kgdb_recover != 0) {
printf("kgdb: caught trap 0x%x at %p\n",
type, (void *)PC_REGS(regs));
kgdb_send("E0E"); /* 14==EFAULT */
longjmp(kgdb_recover);
}
/*
* The first entry to this function is normally through
* a breakpoint trap in kgdb_connect(), in which case we
* must advance past the breakpoint because gdb will not.
*
* Machines vary as to where they leave the PC after a
* breakpoint trap. Those that leave the PC set to the
* address of the trap instruction (i.e. pc532) will not
* define FIXUP_PC_AFTER_BREAK(), and therefore will just
* advance the PC. On machines that leave the PC set to
* the instruction after the trap, FIXUP_PC_AFTER_BREAK
* will be defined to back-up the PC, so that after the
* "first-time" part of the if statement below has run,
* the PC will be the same as it was on entry.
*
* On the first entry here, we expect that gdb is not yet
* listening to us, so just enter the interaction loop.
* After the debugger is "active" (connected) it will be
* waiting for a "signaled" message from us.
*/
if (kgdb_active == 0) {
if (!IS_BREAKPOINT_TRAP(type, 0)) {
/* No debugger active -- let trap handle this. */
return (0);
}
/* Make the PC point at the breakpoint... */
#ifdef FIXUP_PC_AFTER_BREAK
FIXUP_PC_AFTER_BREAK(regs);
#endif
/* ... and then advance past it. */
#ifdef PC_ADVANCE
PC_ADVANCE(regs);
#else
SET_PC_REGS(regs, PC_REGS(regs) + BKPT_SIZE);
#endif
kgdb_active = 1;
} else {
/* Tell remote host that an exception has occurred. */
snprintf(buffer, sizeof buffer, "S%02x", kgdb_signal(type));
kgdb_send(buffer);
}
/* Stick frame regs into our reg cache. */
kgdb_getregs(regs, gdb_regs);
/*
* Interact with gdb until it lets us go.
* If we cause a trap, resume here.
*/
(void)setjmp((kgdb_recover = &jmpbuf));
for (;;) {
kgdb_recv(buffer, sizeof(buffer));
switch (buffer[0]) {
default:
/* Unknown command. */
kgdb_send("");
continue;
case KGDB_SIGNAL:
/*
* if this command came from a running gdb,
* answer it -- the other guy has no way of
* knowing if we're in or out of this loop
* when he issues a "remote-signal".
*/
snprintf(buffer, sizeof buffer, "S%02x",
kgdb_signal(type));
kgdb_send(buffer);
continue;
case KGDB_REG_R:
mem2hex(buffer, gdb_regs, sizeof(gdb_regs));
kgdb_send(buffer);
continue;
case KGDB_REG_W:
p = hex2mem(gdb_regs, buffer + 1, sizeof(gdb_regs));
if (p == NULL || *p != '\0')
kgdb_send("E01");
else {
kgdb_setregs(regs, gdb_regs);
kgdb_send("OK");
}
continue;
case KGDB_MEM_R:
p = buffer + 1;
addr = hex2i(&p);
if (*p++ != ',') {
kgdb_send("E02");
continue;
}
len = hex2i(&p);
if (*p != '\0') {
kgdb_send("E03");
continue;
}
if (len > sizeof(buffer) / 2) {
kgdb_send("E04");
continue;
}
if (kgdb_acc(addr, len) == 0) {
kgdb_send("E05");
continue;
}
db_read_bytes(addr, (size_t)len,
(char *)buffer + sizeof(buffer) / 2);
mem2hex(buffer, buffer + sizeof(buffer) / 2, len);
kgdb_send(buffer);
continue;
case KGDB_MEM_W:
p = buffer + 1;
addr = hex2i(&p);
if (*p++ != ',') {
kgdb_send("E06");
continue;
}
len = hex2i(&p);
if (*p++ != ':') {
kgdb_send("E07");
continue;
}
if (len > (sizeof(buffer) - (p - buffer))) {
kgdb_send("E08");
continue;
}
p = hex2mem(buffer, p, sizeof(buffer));
if (p == NULL) {
kgdb_send("E09");
continue;
}
if (kgdb_acc(addr, len) == 0) {
kgdb_send("E0A");
continue;
}
db_write_bytes(addr, (size_t)len, (char *)buffer);
kgdb_send("OK");
continue;
case KGDB_DETACH:
kgdb_active = 0;
printf("kgdb detached\n");
db_clear_single_step(regs);
kgdb_send("OK");
goto out;
case KGDB_KILL:
kgdb_active = 0;
printf("kgdb detached\n");
db_clear_single_step(regs);
goto out;
case KGDB_CONT:
if (buffer[1]) {
p = buffer + 1;
addr = hex2i(&p);
if (*p) {
kgdb_send("E0B");
continue;
}
SET_PC_REGS(regs, addr);
}
db_clear_single_step(regs);
goto out;
case KGDB_STEP:
if (buffer[1]) {
p = buffer + 1;
addr = hex2i(&p);
if (*p) {
kgdb_send("E0B");
continue;
}
SET_PC_REGS(regs, addr);
}
db_set_single_step(regs);
goto out;
}
}
out:
kgdb_recover = 0;
return (1);
}
boolean_t
db_stop_at_pc(db_regs_t *regs, boolean_t *is_breakpoint)
{
db_addr_t pc, old_pc;
db_breakpoint_t bkpt;
db_clear_breakpoints();
db_clear_watchpoints();
old_pc = pc = PC_REGS(regs);
#ifdef FIXUP_PC_AFTER_BREAK
if (*is_breakpoint) {
/*
* Breakpoint trap. Fix up the PC if the
* machine requires it.
*/
FIXUP_PC_AFTER_BREAK(regs);
pc = PC_REGS(regs);
}
#endif
/*
* Now check for a breakpoint at this address.
*/
bkpt = db_find_breakpoint_here(pc);
if (bkpt) {
if (--bkpt->count == 0) {
db_clear_single_step(regs);
bkpt->count = bkpt->init_count;
*is_breakpoint = TRUE;
return (TRUE); /* stop here */
}
} else if (*is_breakpoint
#ifdef SOFTWARE_SSTEP
&& !((db_taken_bkpt && db_taken_bkpt->address == pc) ||
(db_not_taken_bkpt && db_not_taken_bkpt->address == pc))
#endif
) {
#ifdef PC_ADVANCE
PC_ADVANCE(regs);
#else
# ifdef SET_PC_REGS
SET_PC_REGS(regs, old_pc);
# else
PC_REGS(regs) = old_pc;
# endif
#endif
}
db_clear_single_step(regs);
*is_breakpoint = FALSE;
if (db_run_mode == STEP_INVISIBLE) {
db_run_mode = STEP_CONTINUE;
return (FALSE); /* continue */
}
if (db_run_mode == STEP_COUNT) {
return (FALSE); /* continue */
}
if (db_run_mode == STEP_ONCE) {
if (--db_loop_count > 0) {
if (db_sstep_print) {
db_printf("\t\t");
db_print_loc_and_inst(pc);
db_printf("\n");
}
return (FALSE); /* continue */
}
}
if (db_run_mode == STEP_RETURN) {
db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
/* continue until matching return */
if (!inst_trap_return(ins) &&
(!inst_return(ins) || --db_call_depth != 0)) {
if (db_sstep_print) {
if (inst_call(ins) || inst_return(ins)) {
int i;
db_printf("[after %6d] ", db_inst_count);
for (i = db_call_depth; --i > 0; )
db_printf(" ");
db_print_loc_and_inst(pc);
db_printf("\n");
}
}
if (inst_call(ins))
db_call_depth++;
return (FALSE); /* continue */
}
}
if (db_run_mode == STEP_CALLT) {
db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
/* continue until call or return */
if (!inst_call(ins) && !inst_return(ins) &&
!inst_trap_return(ins)) {
return (FALSE); /* continue */
}
}
db_run_mode = STEP_NONE;
return (TRUE);
}