/*
* 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;
kgdb_entry_notice(type, regs);
if (kgdb_dev == NODEV || kgdb_getc == NULL) {
/* not debugging */
return (0);
}
db_clear_single_step(regs);
if (db_trap_callback)
db_trap_callback(1);
/* 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. */
if (db_trap_callback)
db_trap_callback(0);
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
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;
}
char *ptr = (char *)buffer + sizeof(buffer) / 2;
db_read_bytes(addr, len, ptr);
mem2hex(buffer, ptr, 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, len, (char *)buffer);
kgdb_send("OK");
continue;
case KGDB_DETACH:
case KGDB_KILL:
kgdb_active = 0;
printf("kgdb detached\n");
db_clear_single_step(regs);
kgdb_send("OK");
goto out;
case KGDB_CONT:
if (buffer[1]) {
p = buffer + 1;
addr = hex2i(&p);
if (*p) {
kgdb_send("E0B");
continue;
}
PC_REGS(regs) = addr;
DPRINTF(("kgdb: continuing at %08lx\n", addr));
} else {
DPRINTF((
"kgdb: continuing at old address %08lx\n",
(vaddr_t)PC_REGS(regs)));
}
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;
}
PC_REGS(regs) = addr;
}
db_set_single_step(regs);
goto out;
}
}
out:
if (db_trap_callback)
db_trap_callback(0);
kgdb_recover = 0;
return (1);
}
/*
* This function does all command processing for interfacing to gdb.
*/
static int
handle_exception (struct pt_regs *regs)
{
int addr;
int length;
char *ptr;
kgdb_data kd;
int i;
if (!initialized) {
printf("kgdb: exception before kgdb is initialized! huh?\n");
return (0);
}
/* probably should check which exception occured as well */
if (longjmp_on_fault) {
longjmp_on_fault = 0;
kgdb_longjmp(error_jmp_buf, KGDBERR_MEMFAULT);
panic("kgdb longjump failed!\n");
}
if (kgdb_active) {
printf("kgdb: unexpected exception from within kgdb\n");
return (0);
}
kgdb_active = 1;
kgdb_interruptible(0);
printf("kgdb: handle_exception; trap [0x%x]\n", kgdb_trap(regs));
if (kgdb_setjmp(error_jmp_buf) != 0)
panic("kgdb: error or fault in entry init!\n");
kgdb_enter(regs, &kd);
if (first_entry) {
/*
* the first time we enter kgdb, we save the processor
* state so that we can return to the monitor if the
* remote end quits gdb (or at least, tells us to quit
* with the 'k' packet)
*/
entry_regs = *regs;
first_entry = 0;
}
ptr = remcomOutBuffer;
*ptr++ = 'T';
*ptr++ = hexchars[kd.sigval >> 4];
*ptr++ = hexchars[kd.sigval & 0xf];
for (i = 0; i < kd.nregs; i++) {
kgdb_reg *rp = &kd.regs[i];
*ptr++ = hexchars[rp->num >> 4];
*ptr++ = hexchars[rp->num & 0xf];
*ptr++ = ':';
ptr = (char *)mem2hex((char *)&rp->val, ptr, 4);
*ptr++ = ';';
}
*ptr = 0;
#ifdef KGDB_DEBUG
if (kdebug)
printf("kgdb: remcomOutBuffer: %s\n", remcomOutBuffer);
#endif
putpacket((unsigned char *)&remcomOutBuffer);
while (1) {
volatile int errnum;
remcomOutBuffer[0] = 0;
getpacket(remcomInBuffer);
ptr = &remcomInBuffer[1];
#ifdef KGDB_DEBUG
if (kdebug)
printf("kgdb: remcomInBuffer: %s\n", remcomInBuffer);
#endif
errnum = kgdb_setjmp(error_jmp_buf);
if (errnum == 0) switch (remcomInBuffer[0]) {
case '?': /* report most recent signal */
remcomOutBuffer[0] = 'S';
remcomOutBuffer[1] = hexchars[kd.sigval >> 4];
remcomOutBuffer[2] = hexchars[kd.sigval & 0xf];
remcomOutBuffer[3] = 0;
break;
#ifdef KGDB_DEBUG
case 'd':
/* toggle debug flag */
kdebug ^= 1;
break;
#endif
case 'g': /* return the value of the CPU registers. */
length = kgdb_getregs(regs, remcomRegBuffer, BUFMAX);
mem2hex(remcomRegBuffer, remcomOutBuffer, length);
break;
case 'G': /* set the value of the CPU registers */
length = strlen(ptr);
if ((length & 1) != 0) kgdb_error(KGDBERR_BADPARAMS);
hex2mem(ptr, remcomRegBuffer, length/2);
kgdb_putregs(regs, remcomRegBuffer, length/2);
strcpy(remcomOutBuffer,"OK");
break;
case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
/* Try to read %x,%x. */
if (hexToInt(&ptr, &addr)
&& *ptr++ == ','
&& hexToInt(&ptr, &length)) {
mem2hex((char *)addr, remcomOutBuffer, length);
} else {
kgdb_error(KGDBERR_BADPARAMS);
}
break;
case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */
/* Try to read '%x,%x:'. */
if (hexToInt(&ptr, &addr)
&& *ptr++ == ','
&& hexToInt(&ptr, &length)
&& *ptr++ == ':') {
hex2mem(ptr, (char *)addr, length);
strcpy(remcomOutBuffer, "OK");
} else {
kgdb_error(KGDBERR_BADPARAMS);
}
break;
case 'k': /* kill the program, actually return to monitor */
kd.extype = KGDBEXIT_KILL;
*regs = entry_regs;
first_entry = 1;
goto doexit;
case 'C': /* CSS continue with signal SS */
*ptr = '\0'; /* ignore the signal number for now */
/* fall through */
case 'c': /* cAA..AA Continue; address AA..AA optional */
/* try to read optional parameter, pc unchanged if no parm */
kd.extype = KGDBEXIT_CONTINUE;
if (hexToInt(&ptr, &addr)) {
kd.exaddr = addr;
kd.extype |= KGDBEXIT_WITHADDR;
}
goto doexit;
case 'S': /* SSS single step with signal SS */
*ptr = '\0'; /* ignore the signal number for now */
/* fall through */
case 's':
kd.extype = KGDBEXIT_SINGLE;
if (hexToInt(&ptr, &addr)) {
kd.exaddr = addr;
kd.extype |= KGDBEXIT_WITHADDR;
}
doexit:
/* Need to flush the instruction cache here, as we may have deposited a
* breakpoint, and the icache probably has no way of knowing that a data ref to
* some location may have changed something that is in the instruction cache.
*/
kgdb_flush_cache_all();
kgdb_exit(regs, &kd);
kgdb_active = 0;
kgdb_interruptible(1);
return (1);
case 'r': /* Reset (if user process..exit ???)*/
panic("kgdb reset.");
break;
case 'P': /* Pr=v set reg r to value v (r and v are hex) */
if (hexToInt(&ptr, &addr)
&& *ptr++ == '='
&& ((length = strlen(ptr)) & 1) == 0) {
hex2mem(ptr, remcomRegBuffer, length/2);
kgdb_putreg(regs, addr,
remcomRegBuffer, length/2);
strcpy(remcomOutBuffer,"OK");
} else {
kgdb_error(KGDBERR_BADPARAMS);
}
break;
} /* switch */
if (errnum != 0)
sprintf(remcomOutBuffer, "E%02d", errnum);
#ifdef KGDB_DEBUG
if (kdebug)
printf("kgdb: remcomOutBuffer: %s\n", remcomOutBuffer);
#endif
/* reply to the request */
putpacket((unsigned char *)&remcomOutBuffer);
} /* while(1) */
}
