int
kdb(int reason, int error, struct pt_regs *regs)
{
char cmdbuf[255];
char *cmd;
int diag;
unsigned long flags;
struct pt_regs func_regs;
kdb_new_cpu = -1;
/*
* Remove the breakpoints to prevent double-faults
* if kdb happens to use a function where a breakpoint
* has been enabled.
*/
kdb_bp_remove();
if (reason != KDB_REASON_DEBUG) {
kdb_printf("Entering kdb ");
#if defined(__SMP__)
kdb_printf("on processor %d ", smp_processor_id());
#endif
}
switch (reason) {
case KDB_REASON_DEBUG:
/*
* If re-entering kdb after a single step
* command, don't print the message.
*/
diag = kdb_db_trap(regs);
if (diag == 0) {
kdb_printf("Entering kdb ");
#if defined(__SMP__)
kdb_printf("on processor %d ", smp_processor_id());
#endif
} else if (diag == 2) {
/*
* in middle of ssb command. Just return.
*/
return 0;
}
break;
case KDB_REASON_FAULT:
break;
case KDB_REASON_INT:
kdb_printf("due to KDB_ENTER() call\n");
break;
case KDB_REASON_KEYBOARD:
kdb_printf("due to Keyboard Entry\n");
break;
case KDB_REASON_SWITCH:
kdb_printf("due to cpu switch\n");
break;
case KDB_REASON_ENTER:
kdb_printf("due to function call\n");
regs = &func_regs;
regs->xcs = 0;
#if defined(CONFIG_KDB_FRAMEPTR)
asm volatile("movl %%ebp,%0":"=m" (*(int *)®s->ebp));
#endif
asm volatile("movl %%esp,%0":"=m" (*(int *)®s->esp));
regs->eip = (long) &kdb; /* for traceback. */
break;
case KDB_REASON_PANIC:
kdb_printf("due to panic @ 0x%8.8x\n", regs->eip);
kdbdumpregs(regs, NULL, NULL);
break;
case KDB_REASON_BREAK:
kdb_printf("due to Breakpoint @ 0x%8.8x\n", regs->eip);
break;
default:
break;
}
#if defined(__SMP__)
/*
* If SMP, stop other processors
*/
if (smp_num_cpus > 1) {
/*
* Stop all other processors
*/
smp_kdb_stop(1);
}
#endif /* __SMP__ */
/*
* Disable interrupts during kdb command processing
*/
__save_flags(flags);
__cli();
while (1) {
/*
* Initialize pager context.
*/
kdb_nextline = 1;
/*
* Use kdb_setjmp/kdb_longjmp to break out of
* the pager early.
*/
if (kdb_setjmp(&kdbjmpbuf)) {
/*
* Command aborted (usually in pager)
*/
/*
* XXX - need to abort a SSB ?
*/
continue;
}
/*
* Fetch command from keyboard
*/
cmd = kbd_getstr(cmdbuf, sizeof(cmdbuf), kdbgetenv("PROMPT"));
diag = kdb_parse(cmd, regs);
if (diag == KDB_NOTFOUND) {
kdb_printf("Unknown kdb command: '%s'\n", cmd);
diag = 0;
}
if ((diag == KDB_GO)
|| (diag == KDB_CPUSWITCH))
break; /* Go or cpu switch command */
if (diag)
kdb_cmderror(diag);
}
/*
* Set up debug registers.
*/
kdb_bp_install();
#if defined(__SMP__)
if ((diag == KDB_CPUSWITCH)
&& (kdb_new_cpu != -1)) {
/*
* Leaving the other CPU's at the barrier, except the
* one we are switching to, we'll send ourselves a
* kdb IPI before allowing interrupts so it will get
* caught ASAP and get this CPU back waiting at the barrier.
*/
smp_kdb_stop(0); /* Stop ourself */
/*
* let the new cpu go.
*/
clear_bit(kdb_new_cpu, &smp_kdb_wait);
} else {
/*
* Let the other processors continue.
*/
smp_kdb_wait = 0;
}
#endif
kdb_flags &= ~(KDB_FLAG_SUPRESS|KDB_FLAG_FAULT);
__restore_flags(flags);
return 0;
}
int kdb_stub(struct kgdb_state *ks)
{
int error = 0;
kdb_bp_t *bp;
unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
kdb_reason_t reason = KDB_REASON_OOPS;
kdb_dbtrap_t db_result = KDB_DB_NOBPT;
int i;
if (KDB_STATE(REENTRY)) {
reason = KDB_REASON_SWITCH;
KDB_STATE_CLEAR(REENTRY);
addr = instruction_pointer(ks->linux_regs);
}
ks->pass_exception = 0;
if (atomic_read(&kgdb_setting_breakpoint))
reason = KDB_REASON_KEYBOARD;
for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
reason = KDB_REASON_BREAK;
db_result = KDB_DB_BPT;
if (addr != instruction_pointer(ks->linux_regs))
kgdb_arch_set_pc(ks->linux_regs, addr);
break;
}
}
if (reason == KDB_REASON_BREAK || reason == KDB_REASON_SWITCH) {
for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
if (bp->bp_free)
continue;
if (bp->bp_addr == addr) {
bp->bp_delay = 1;
bp->bp_delayed = 1;
/*
* SSBPT is set when the kernel debugger must single step a
* task in order to re-establish an instruction breakpoint
* which uses the instruction replacement mechanism. It is
* cleared by any action that removes the need to single-step
* the breakpoint.
*/
reason = KDB_REASON_BREAK;
db_result = KDB_DB_BPT;
KDB_STATE_SET(SSBPT);
break;
}
}
}
if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
ks->signo == SIGTRAP) {
reason = KDB_REASON_SSTEP;
db_result = KDB_DB_BPT;
}
/* Set initial kdb state variables */
KDB_STATE_CLEAR(KGDB_TRANS);
kdb_initial_cpu = ks->cpu;
kdb_current_task = kgdb_info[ks->cpu].task;
kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
/* Remove any breakpoints as needed by kdb and clear single step */
kdb_bp_remove();
KDB_STATE_CLEAR(DOING_SS);
KDB_STATE_CLEAR(DOING_SSB);
KDB_STATE_SET(PAGER);
/* zero out any offline cpu data */
for_each_present_cpu(i) {
if (!cpu_online(i)) {
kgdb_info[i].debuggerinfo = NULL;
kgdb_info[i].task = NULL;
}
}
if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) {
ks->pass_exception = 1;
KDB_FLAG_SET(CATASTROPHIC);
}
kdb_initial_cpu = ks->cpu;
if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
KDB_STATE_CLEAR(SSBPT);
KDB_STATE_CLEAR(DOING_SS);
} else {
/* Start kdb main loop */
error = kdb_main_loop(KDB_REASON_ENTER, reason,
ks->err_code, db_result, ks->linux_regs);
}
/*
* Upon exit from the kdb main loop setup break points and restart
* the system based on the requested continue state
*/
kdb_initial_cpu = -1;
kdb_current_task = NULL;
kdb_current_regs = NULL;
KDB_STATE_CLEAR(PAGER);
kdbnearsym_cleanup();
if (error == KDB_CMD_KGDB) {
if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {
/*
* This inteface glue which allows kdb to transition in into
* the gdb stub. In order to do this the '?' or '' gdb serial
* packet response is processed here. And then control is
* passed to the gdbstub.
*/
if (KDB_STATE(DOING_KGDB))
gdbstub_state(ks, "?");
else
gdbstub_state(ks, "");
KDB_STATE_CLEAR(DOING_KGDB);
KDB_STATE_CLEAR(DOING_KGDB2);
}
return DBG_PASS_EVENT;
}
kdb_bp_install(ks->linux_regs);
dbg_activate_sw_breakpoints();
/* Set the exit state to a single step or a continue */
if (KDB_STATE(DOING_SS))
gdbstub_state(ks, "s");
else
gdbstub_state(ks, "c");
KDB_FLAG_CLEAR(CATASTROPHIC);
/* Invoke arch specific exception handling prior to system resume */
kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
if (ks->pass_exception)
kgdb_info[ks->cpu].ret_state = 1;
if (error == KDB_CMD_CPU) {
KDB_STATE_SET(REENTRY);
/*
* Force clear the single step bit because kdb emulates this
* differently vs the gdbstub
*/
kgdb_single_step = 0;
dbg_deactivate_sw_breakpoints();
return DBG_SWITCH_CPU_EVENT;
}
return kgdb_info[ks->cpu].ret_state;
}
