[deliverable/linux.git] / kernel / debug / kdb / kdb_debugger.c

/*
 * Created by: Jason Wessel <jason.wessel@windriver.com>
 *
 * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/kgdb.h>
#include <linux/kdb.h>
#include <linux/kdebug.h>
#include "kdb_private.h"
#include "../debug_core.h"

/*
 * KDB interface to KGDB internals
 */
get_char_func kdb_poll_funcs[] = {
	dbg_io_get_char,
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
};
EXPORT_SYMBOL_GPL(kdb_poll_funcs);

int kdb_poll_idx = 1;
EXPORT_SYMBOL_GPL(kdb_poll_idx);

static struct kgdb_state *kdb_ks;

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;

	kdb_ks = ks;
	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 = atomic_read(&kgdb_active);
	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);
	}
	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_CLEAR(DOING_KGDB);
		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;
}

void kdb_gdb_state_pass(char *buf)
{
	gdbstub_state(kdb_ks, buf);
}
Commit	Line	Data
5d5314d6 JW	1	/*
	2	* Created by: Jason Wessel <jason.wessel@windriver.com>
	3	*
	4	* Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
	5	*
	6	* This file is licensed under the terms of the GNU General Public
	7	* License version 2. This program is licensed "as is" without any
	8	* warranty of any kind, whether express or implied.
	9	*/
	10
	11	#include <linux/kgdb.h>
	12	#include <linux/kdb.h>
	13	#include <linux/kdebug.h>
	14	#include "kdb_private.h"
	15	#include "../debug_core.h"
	16
	17	/*
	18	* KDB interface to KGDB internals
	19	*/
	20	get_char_func kdb_poll_funcs[] = {
	21	dbg_io_get_char,
	22	NULL,
f5316b4a JW	23	NULL,
	24	NULL,
	25	NULL,
	26	NULL,
5d5314d6	27	};
f5316b4a JW	28	EXPORT_SYMBOL_GPL(kdb_poll_funcs);
	29
	30	int kdb_poll_idx = 1;
	31	EXPORT_SYMBOL_GPL(kdb_poll_idx);
5d5314d6	32
f679c498 JW	33	static struct kgdb_state *kdb_ks;
f679c498 JW	34
5d5314d6 JW	35	int kdb_stub(struct kgdb_state *ks)
	36	{
	37	int error = 0;
	38	kdb_bp_t *bp;
	39	unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
	40	kdb_reason_t reason = KDB_REASON_OOPS;
	41	kdb_dbtrap_t db_result = KDB_DB_NOBPT;
	42	int i;
	43
f679c498	44	kdb_ks = ks;
5d5314d6 JW	45	if (KDB_STATE(REENTRY)) {
	46	reason = KDB_REASON_SWITCH;
	47	KDB_STATE_CLEAR(REENTRY);
	48	addr = instruction_pointer(ks->linux_regs);
	49	}
	50	ks->pass_exception = 0;
	51	if (atomic_read(&kgdb_setting_breakpoint))
	52	reason = KDB_REASON_KEYBOARD;
	53
	54	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
	55	if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
	56	reason = KDB_REASON_BREAK;
	57	db_result = KDB_DB_BPT;
	58	if (addr != instruction_pointer(ks->linux_regs))
	59	kgdb_arch_set_pc(ks->linux_regs, addr);
	60	break;
	61	}
	62	}
	63	if (reason == KDB_REASON_BREAK \|\| reason == KDB_REASON_SWITCH) {
	64	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
	65	if (bp->bp_free)
	66	continue;
	67	if (bp->bp_addr == addr) {
	68	bp->bp_delay = 1;
	69	bp->bp_delayed = 1;
	70	/*
	71	* SSBPT is set when the kernel debugger must single step a
	72	* task in order to re-establish an instruction breakpoint
	73	* which uses the instruction replacement mechanism. It is
	74	* cleared by any action that removes the need to single-step
	75	* the breakpoint.
	76	*/
	77	reason = KDB_REASON_BREAK;
	78	db_result = KDB_DB_BPT;
	79	KDB_STATE_SET(SSBPT);
	80	break;
	81	}
	82	}
	83	}
	84
	85	if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
	86	ks->signo == SIGTRAP) {
	87	reason = KDB_REASON_SSTEP;
	88	db_result = KDB_DB_BPT;
	89	}
	90	/* Set initial kdb state variables */
	91	KDB_STATE_CLEAR(KGDB_TRANS);
495363d3	92	kdb_initial_cpu = atomic_read(&kgdb_active);
5d5314d6 JW	93	kdb_current_task = kgdb_info[ks->cpu].task;
	94	kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
	95	/* Remove any breakpoints as needed by kdb and clear single step */
	96	kdb_bp_remove();
	97	KDB_STATE_CLEAR(DOING_SS);
	98	KDB_STATE_CLEAR(DOING_SSB);
f5316b4a	99	KDB_STATE_SET(PAGER);
5d5314d6 JW	100	/* zero out any offline cpu data */
	101	for_each_present_cpu(i) {
	102	if (!cpu_online(i)) {
	103	kgdb_info[i].debuggerinfo = NULL;
	104	kgdb_info[i].task = NULL;
	105	}
	106	}
	107	if (ks->err_code == DIE_OOPS \|\| reason == KDB_REASON_OOPS) {
	108	ks->pass_exception = 1;
	109	KDB_FLAG_SET(CATASTROPHIC);
	110	}
5d5314d6 JW	111	if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
	112	KDB_STATE_CLEAR(SSBPT);
	113	KDB_STATE_CLEAR(DOING_SS);
	114	} else {
	115	/* Start kdb main loop */
	116	error = kdb_main_loop(KDB_REASON_ENTER, reason,
	117	ks->err_code, db_result, ks->linux_regs);
	118	}
	119	/*
	120	* Upon exit from the kdb main loop setup break points and restart
	121	* the system based on the requested continue state
	122	*/
	123	kdb_initial_cpu = -1;
	124	kdb_current_task = NULL;
	125	kdb_current_regs = NULL;
f5316b4a	126	KDB_STATE_CLEAR(PAGER);
5d5314d6 JW	127	kdbnearsym_cleanup();
5d5314d6 JW	128	if (error == KDB_CMD_KGDB) {
d613d828	129	if (KDB_STATE(DOING_KGDB))
5d5314d6	130	KDB_STATE_CLEAR(DOING_KGDB);
5d5314d6 JW	131	return DBG_PASS_EVENT;
	132	}
	133	kdb_bp_install(ks->linux_regs);
	134	dbg_activate_sw_breakpoints();
	135	/* Set the exit state to a single step or a continue */
	136	if (KDB_STATE(DOING_SS))
	137	gdbstub_state(ks, "s");
	138	else
	139	gdbstub_state(ks, "c");
	140
	141	KDB_FLAG_CLEAR(CATASTROPHIC);
	142
	143	/* Invoke arch specific exception handling prior to system resume */
	144	kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
	145	if (ks->pass_exception)
	146	kgdb_info[ks->cpu].ret_state = 1;
	147	if (error == KDB_CMD_CPU) {
	148	KDB_STATE_SET(REENTRY);
	149	/*
	150	* Force clear the single step bit because kdb emulates this
	151	* differently vs the gdbstub
	152	*/
	153	kgdb_single_step = 0;
	154	dbg_deactivate_sw_breakpoints();
	155	return DBG_SWITCH_CPU_EVENT;
	156	}
	157	return kgdb_info[ks->cpu].ret_state;
	158	}
	159
f679c498 JW	160	void kdb_gdb_state_pass(char *buf)
	161	{
	162	gdbstub_state(kdb_ks, buf);
	163	}