[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 <linux/export.h>
#include <linux/hardirq.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_common_init_state(struct kgdb_state *ks)
{
	kdb_initial_cpu = atomic_read(&kgdb_active);
	kdb_current_task = kgdb_info[ks->cpu].task;
	kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
	return 0;
}

int kdb_common_deinit_state(void)
{
	kdb_initial_cpu = -1;
	kdb_current_task = NULL;
	kdb_current_regs = NULL;
	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;

	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;

	if (ks->err_code == KDB_REASON_SYSTEM_NMI && ks->signo == SIGTRAP)
		reason = KDB_REASON_SYSTEM_NMI;

	else if (in_nmi())
		reason = KDB_REASON_NMI;

	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_common_init_state(ks);
	/* Remove any breakpoints as needed by kdb and clear single step */
	kdb_bp_remove();
	KDB_STATE_CLEAR(DOING_SS);
	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);
	}
	/* set CATASTROPHIC if the system contains unresponsive processors */
	for_each_online_cpu(i)
		if (!kgdb_info[i].enter_kgdb)
			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_common_deinit_state();
	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>
6e5fdeed	14	#include <linux/export.h>
b10d22d6	15	#include <linux/hardirq.h>
5d5314d6 JW	16	#include "kdb_private.h"
	17	#include "../debug_core.h"
	18
	19	/*
	20	* KDB interface to KGDB internals
	21	*/
	22	get_char_func kdb_poll_funcs[] = {
	23	dbg_io_get_char,
	24	NULL,
f5316b4a JW	25	NULL,
	26	NULL,
	27	NULL,
	28	NULL,
5d5314d6	29	};
f5316b4a JW	30	EXPORT_SYMBOL_GPL(kdb_poll_funcs);
	31
	32	int kdb_poll_idx = 1;
	33	EXPORT_SYMBOL_GPL(kdb_poll_idx);
5d5314d6	34
f679c498 JW	35	static struct kgdb_state *kdb_ks;
f679c498 JW	36
00370b8f MK	37	int kdb_common_init_state(struct kgdb_state *ks)
	38	{
	39	kdb_initial_cpu = atomic_read(&kgdb_active);
	40	kdb_current_task = kgdb_info[ks->cpu].task;
	41	kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
	42	return 0;
	43	}
	44
	45	int kdb_common_deinit_state(void)
	46	{
	47	kdb_initial_cpu = -1;
	48	kdb_current_task = NULL;
	49	kdb_current_regs = NULL;
	50	return 0;
	51	}
	52
5d5314d6 JW	53	int kdb_stub(struct kgdb_state *ks)
	54	{
	55	int error = 0;
	56	kdb_bp_t *bp;
	57	unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
	58	kdb_reason_t reason = KDB_REASON_OOPS;
	59	kdb_dbtrap_t db_result = KDB_DB_NOBPT;
	60	int i;
	61
f679c498	62	kdb_ks = ks;
5d5314d6 JW	63	if (KDB_STATE(REENTRY)) {
	64	reason = KDB_REASON_SWITCH;
	65	KDB_STATE_CLEAR(REENTRY);
	66	addr = instruction_pointer(ks->linux_regs);
	67	}
	68	ks->pass_exception = 0;
	69	if (atomic_read(&kgdb_setting_breakpoint))
	70	reason = KDB_REASON_KEYBOARD;
	71
8daaa5f8 MT	72	if (ks->err_code == KDB_REASON_SYSTEM_NMI && ks->signo == SIGTRAP)
	73	reason = KDB_REASON_SYSTEM_NMI;
	74
	75	else if (in_nmi())
b10d22d6 AV	76	reason = KDB_REASON_NMI;
b10d22d6 AV	77
5d5314d6 JW	78	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
	79	if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
	80	reason = KDB_REASON_BREAK;
	81	db_result = KDB_DB_BPT;
	82	if (addr != instruction_pointer(ks->linux_regs))
	83	kgdb_arch_set_pc(ks->linux_regs, addr);
	84	break;
	85	}
	86	}
	87	if (reason == KDB_REASON_BREAK \|\| reason == KDB_REASON_SWITCH) {
	88	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
	89	if (bp->bp_free)
	90	continue;
	91	if (bp->bp_addr == addr) {
	92	bp->bp_delay = 1;
	93	bp->bp_delayed = 1;
	94	/*
	95	* SSBPT is set when the kernel debugger must single step a
	96	* task in order to re-establish an instruction breakpoint
	97	* which uses the instruction replacement mechanism. It is
	98	* cleared by any action that removes the need to single-step
	99	* the breakpoint.
	100	*/
	101	reason = KDB_REASON_BREAK;
	102	db_result = KDB_DB_BPT;
	103	KDB_STATE_SET(SSBPT);
	104	break;
	105	}
	106	}
	107	}
	108
	109	if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
	110	ks->signo == SIGTRAP) {
	111	reason = KDB_REASON_SSTEP;
	112	db_result = KDB_DB_BPT;
	113	}
	114	/* Set initial kdb state variables */
	115	KDB_STATE_CLEAR(KGDB_TRANS);
00370b8f	116	kdb_common_init_state(ks);
5d5314d6 JW	117	/* Remove any breakpoints as needed by kdb and clear single step */
	118	kdb_bp_remove();
	119	KDB_STATE_CLEAR(DOING_SS);
f5316b4a	120	KDB_STATE_SET(PAGER);
5d5314d6 JW	121	/* zero out any offline cpu data */
	122	for_each_present_cpu(i) {
	123	if (!cpu_online(i)) {
	124	kgdb_info[i].debuggerinfo = NULL;
	125	kgdb_info[i].task = NULL;
	126	}
	127	}
	128	if (ks->err_code == DIE_OOPS \|\| reason == KDB_REASON_OOPS) {
	129	ks->pass_exception = 1;
	130	KDB_FLAG_SET(CATASTROPHIC);
	131	}
a1465d2f DT	132	/* set CATASTROPHIC if the system contains unresponsive processors */
	133	for_each_online_cpu(i)
	134	if (!kgdb_info[i].enter_kgdb)
	135	KDB_FLAG_SET(CATASTROPHIC);
5d5314d6 JW	136	if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
	137	KDB_STATE_CLEAR(SSBPT);
	138	KDB_STATE_CLEAR(DOING_SS);
	139	} else {
	140	/* Start kdb main loop */
	141	error = kdb_main_loop(KDB_REASON_ENTER, reason,
	142	ks->err_code, db_result, ks->linux_regs);
	143	}
	144	/*
	145	* Upon exit from the kdb main loop setup break points and restart
	146	* the system based on the requested continue state
	147	*/
00370b8f	148	kdb_common_deinit_state();
f5316b4a	149	KDB_STATE_CLEAR(PAGER);
5d5314d6 JW	150	kdbnearsym_cleanup();
5d5314d6 JW	151	if (error == KDB_CMD_KGDB) {
d613d828	152	if (KDB_STATE(DOING_KGDB))
5d5314d6	153	KDB_STATE_CLEAR(DOING_KGDB);
5d5314d6 JW	154	return DBG_PASS_EVENT;
	155	}
	156	kdb_bp_install(ks->linux_regs);
	157	dbg_activate_sw_breakpoints();
	158	/* Set the exit state to a single step or a continue */
	159	if (KDB_STATE(DOING_SS))
	160	gdbstub_state(ks, "s");
	161	else
	162	gdbstub_state(ks, "c");
	163
	164	KDB_FLAG_CLEAR(CATASTROPHIC);
	165
	166	/* Invoke arch specific exception handling prior to system resume */
	167	kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
	168	if (ks->pass_exception)
	169	kgdb_info[ks->cpu].ret_state = 1;
	170	if (error == KDB_CMD_CPU) {
	171	KDB_STATE_SET(REENTRY);
	172	/*
	173	* Force clear the single step bit because kdb emulates this
	174	* differently vs the gdbstub
	175	*/
	176	kgdb_single_step = 0;
	177	dbg_deactivate_sw_breakpoints();
	178	return DBG_SWITCH_CPU_EVENT;
	179	}
	180	return kgdb_info[ks->cpu].ret_state;
	181	}
	182
f679c498 JW	183	void kdb_gdb_state_pass(char *buf)
	184	{
	185	gdbstub_state(kdb_ks, buf);
	186	}