/*
* Receive a packet.
*/
static int
kgdb_recv(u_char *bp, int maxlen)
{
u_char *p;
int c, csum, tmpcsum;
int len;
DPRINTF(("kgdb_recv: "));
do {
p = bp;
csum = len = 0;
while ((c = GETC()) != KGDB_START)
DPRINTF(("%c",c));
DPRINTF(("%c Start ",c));
while ((c = GETC()) != KGDB_END && len < maxlen) {
DPRINTF(("%c",c));
c &= 0x7f;
csum += c;
*p++ = c;
len++;
}
csum &= 0xff;
*p = '\0';
DPRINTF(("%c End ", c));
if (len >= maxlen) {
DPRINTF(("Long- "));
PUTC(KGDB_BADP);
continue;
}
tmpcsum = csum;
c = GETC();
DPRINTF(("%c",c));
csum -= digit2i(c) * 16;
c = GETC();
DPRINTF(("%c",c));
csum -= digit2i(c);
if (csum == 0) {
DPRINTF(("Good+ "));
PUTC(KGDB_GOODP);
/* Sequence present? */
if (bp[2] == ':') {
DPRINTF(("Seq %c%c ", bp[0], bp[1]));
PUTC(bp[0]);
PUTC(bp[1]);
len -= 3;
kgdb_copy(bp + 3, bp, len);
}
break;
}
DPRINTF((" Bad(wanted %x, off by %d)- ", tmpcsum, csum));
__USE(tmpcsum);
PUTC(KGDB_BADP);
} while (1);
DPRINTF(("kgdb_recv: %s\n", bp));
return (len);
}
/*
* Receive a packet.
*/
static int
kgdb_recv(u_char *bp, int maxlen)
{
u_char *p;
int c, csum;
int len;
do {
p = bp;
csum = len = 0;
while ((c = GETC()) != KGDB_START)
;
while ((c = GETC()) != KGDB_END && len < maxlen) {
c &= 0x7f;
csum += c;
*p++ = c;
len++;
}
csum &= 0xff;
*p = '\0';
if (len >= maxlen) {
PUTC(KGDB_BADP);
continue;
}
csum -= digit2i(GETC()) * 16;
csum -= digit2i(GETC());
if (csum == 0) {
PUTC(KGDB_GOODP);
/* Sequence present? */
if (bp[2] == ':') {
PUTC(bp[0]);
PUTC(bp[1]);
len -= 3;
kgdb_copy(bp + 3, bp, len);
}
break;
}
PUTC(KGDB_BADP);
} while (1);
#ifdef DEBUG_KGDB
printf("kgdb_recv: %s\n", bp);
#endif
return (len);
}
/*
* This function does all command procesing for interfacing to
* a remote gdb.
*/
int
kgdb_trap(int type, struct frame *frame)
{
u_long len;
u_char *addr;
u_char *cp;
u_char out, in;
int outlen;
int inlen;
u_long gdb_regs[NUM_REGS];
if ((int)kgdb_dev < 0) {
/* not debugging */
return (0);
}
if (kgdb_active == 0) {
if (type != T_TRAP15) {
/* No debugger active -- let trap handle this. */
return (0);
}
kgdb_getc = 0;
for (inlen = 0; constab[inlen].cn_probe; inlen++)
if (major(constab[inlen].cn_dev) == major(kgdb_dev)) {
kgdb_getc = constab[inlen].cn_getc;
kgdb_putc = constab[inlen].cn_putc;
break;
}
if (kgdb_getc == 0 || kgdb_putc == 0)
return (0);
/*
* If the packet that woke us up isn't an exec packet,
* ignore it since there is no active debugger. Also,
* we check that it's not an ack to be sure that the
* remote side doesn't send back a response after the
* local gdb has exited. Otherwise, the local host
* could trap into gdb if it's running a gdb kernel too.
*/
in = GETC;
/*
* If we came in asynchronously through the serial line,
* the framing character is eaten by the receive interrupt,
* but if we come in through a synchronous trap (i.e., via
* kgdb_connect()), we will see the extra character.
*/
if (in == FRAME_START)
in = GETC;
/*
* Check that this is a debugger exec message. If so,
* slurp up the entire message then ack it, and fall
* through to the recv loop.
*/
if (KGDB_CMD(in) != KGDB_EXEC || (in & KGDB_ACK) != 0)
return (0);
while (GETC != FRAME_END)
;
/*
* Do the printf *before* we ack the message. This way
* we won't drop any inbound characters while we're
* doing the polling printf.
*/
printf("kgdb started from device %x\n", kgdb_dev);
kgdb_send(in | KGDB_ACK, (u_char *)0, 0);
kgdb_active = 1;
}
/*
* Stick frame regs into our reg cache then tell remote host
* that an exception has occurred.
*/
regs_to_gdb(frame, gdb_regs);
if (type != T_TRAP15) {
/*
* Only send an asynchronous SIGNAL message when we hit
* a breakpoint. Otherwise, we will drop the incoming
* packet while we output this one (and on entry the other
* side isn't interested in the SIGNAL type -- if it is,
* it will have used a signal packet.)
*/
outbuffer[0] = computeSignal(type);
kgdb_send(KGDB_SIGNAL, outbuffer, 1);
}
while (1) {
in = kgdb_recv(inbuffer, &inlen);
if (in == 0 || (in & KGDB_ACK))
/* Ignore inbound acks and error conditions. */
continue;
out = in | KGDB_ACK;
switch (KGDB_CMD(in)) {
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". (Note
* that without the length check, we could
* loop here forever if the ourput line is
* looped back or the remote host is echoing.)
*/
if (inlen == 0) {
outbuffer[0] = computeSignal(type);
kgdb_send(KGDB_SIGNAL, outbuffer, 1);
}
continue;
case KGDB_REG_R:
case KGDB_REG_R | KGDB_DELTA:
cp = outbuffer;
outlen = 0;
for (len = inbuffer[0]; len < NUM_REGS; ++len) {
if (reg_cache[len] != gdb_regs[len] ||
(in & KGDB_DELTA) == 0) {
if (outlen + 5 > SL_MAXDATA) {
out |= KGDB_MORE;
break;
}
cp[outlen] = len;
kgdb_copy((u_char *)&gdb_regs[len],
&cp[outlen + 1], 4);
reg_cache[len] = gdb_regs[len];
outlen += 5;
}
}
break;
case KGDB_REG_W:
case KGDB_REG_W | KGDB_DELTA:
cp = inbuffer;
for (len = 0; len < inlen; len += 5) {
int j = cp[len];
kgdb_copy(&cp[len + 1],
(u_char *)&gdb_regs[j], 4);
reg_cache[j] = gdb_regs[j];
}
gdb_to_regs(frame, gdb_regs);
outlen = 0;
break;
case KGDB_MEM_R:
len = inbuffer[0];
kgdb_copy(&inbuffer[1], (u_char *)&addr, 4);
if (len > SL_MAXDATA) {
outlen = 1;
outbuffer[0] = E2BIG;
} else if (!kgdb_acc(addr, len, B_READ)) {
outlen = 1;
outbuffer[0] = EFAULT;
} else {
outlen = len + 1;
outbuffer[0] = 0;
kgdb_copy(addr, &outbuffer[1], len);
}
break;
case KGDB_MEM_W:
len = inlen - 4;
kgdb_copy(inbuffer, (u_char *)&addr, 4);
outlen = 1;
if (!kgdb_acc(addr, len, B_READ))
outbuffer[0] = EFAULT;
else {
outbuffer[0] = 0;
if (!kgdb_acc(addr, len, B_WRITE))
chgkprot(addr, len, B_WRITE);
kgdb_copy(&inbuffer[4], addr, len);
ICIA();
}
break;
case KGDB_KILL:
kgdb_active = 0;
printf("kgdb detached\n");
/* fall through */
case KGDB_CONT:
kgdb_send(out, 0, 0);
frame->f_sr &=~ PSL_T;
return (1);
case KGDB_STEP:
kgdb_send(out, 0, 0);
frame->f_sr |= PSL_T;
return (1);
case KGDB_EXEC:
default:
/* Unknown command. Ack with a null message. */
outlen = 0;
break;
}
/* Send the reply */
kgdb_send(out, outbuffer, outlen);
}
}
static inline void
gdb_to_regs(struct frame *fp, u_long *regs)
{
kgdb_copy((u_char *)regs, (u_char *)fp->f_regs, 16*4);
kgdb_copy((u_char *)®s[GDB_SR], (u_char *)&fp->f_stackadj, 2*4);
}
