void
kgdb_error(int errnum)
{
longjmp_on_fault = 0;
kgdb_longjmp(error_jmp_buf, errnum);
panic("kgdb_error: longjmp failed!\n");
}
void
kgdb_panic(
const char *message)
{
KGDB_DEBUG(("kgdb_panic: %s\n", message));
/*
* Remember the message and bomb out
*/
kgdb_panic_msg = message;
kgdb_longjmp(kgdb_recover, 1);
/* NOTREACHED */
}
void
bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
{
extern void die(const char*, struct pt_regs*, long);
const struct exception_table_entry *entry;
#ifdef CONFIG_KGDB
if (atomic_read(&debugger_active) && kgdb_may_fault) {
/* Restore our previous state. */
kgdb_longjmp(kgdb_fault_jmp_regs);
return;
}
#endif
/* Are we prepared to handle this kernel fault? */
if ((entry = search_exception_tables(regs->pc)) != NULL) {
#if DEBUG_PAGE_FAULT
printk(KERN_DEBUG "%s: Exception at pc=%#010lx (%lx)\n",
current->comm, regs->pc, entry->fixup);
#endif
current->thread.bad_uaddr = address;
regs->pc = entry->fixup;
return;
}
/* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
printk(KERN_ALERT "Unable to handle kernel paging request at virtual "
"address %08lx\n pc = %08lx, ra = %08lx\n",
address, regs->pc, regs->areg[0]);
die("Oops", regs, sig);
do_exit(sig);
}
/*
* 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) */
}
