[mirror_ubuntu-zesty-kernel.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 "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>
6e5fdeed	14	#include <linux/export.h>
5d5314d6 JW	15	#include "kdb_private.h"
	16	#include "../debug_core.h"
	17
	18	/*
	19	* KDB interface to KGDB internals
	20	*/
	21	get_char_func kdb_poll_funcs[] = {
	22	dbg_io_get_char,
	23	NULL,
f5316b4a JW	24	NULL,
	25	NULL,
	26	NULL,
	27	NULL,
5d5314d6	28	};
f5316b4a JW	29	EXPORT_SYMBOL_GPL(kdb_poll_funcs);
	30
	31	int kdb_poll_idx = 1;
	32	EXPORT_SYMBOL_GPL(kdb_poll_idx);
5d5314d6	33
f679c498 JW	34	static struct kgdb_state *kdb_ks;
f679c498 JW	35
5d5314d6 JW	36	int kdb_stub(struct kgdb_state *ks)
	37	{
	38	int error = 0;
	39	kdb_bp_t *bp;
	40	unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
	41	kdb_reason_t reason = KDB_REASON_OOPS;
	42	kdb_dbtrap_t db_result = KDB_DB_NOBPT;
	43	int i;
	44
f679c498	45	kdb_ks = ks;
5d5314d6 JW	46	if (KDB_STATE(REENTRY)) {
	47	reason = KDB_REASON_SWITCH;
	48	KDB_STATE_CLEAR(REENTRY);
	49	addr = instruction_pointer(ks->linux_regs);
	50	}
	51	ks->pass_exception = 0;
	52	if (atomic_read(&kgdb_setting_breakpoint))
	53	reason = KDB_REASON_KEYBOARD;
	54
	55	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
	56	if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
	57	reason = KDB_REASON_BREAK;
	58	db_result = KDB_DB_BPT;
	59	if (addr != instruction_pointer(ks->linux_regs))
	60	kgdb_arch_set_pc(ks->linux_regs, addr);
	61	break;
	62	}
	63	}
	64	if (reason == KDB_REASON_BREAK \|\| reason == KDB_REASON_SWITCH) {
	65	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
	66	if (bp->bp_free)
	67	continue;
	68	if (bp->bp_addr == addr) {
	69	bp->bp_delay = 1;
	70	bp->bp_delayed = 1;
	71	/*
	72	* SSBPT is set when the kernel debugger must single step a
	73	* task in order to re-establish an instruction breakpoint
	74	* which uses the instruction replacement mechanism. It is
	75	* cleared by any action that removes the need to single-step
	76	* the breakpoint.
	77	*/
	78	reason = KDB_REASON_BREAK;
	79	db_result = KDB_DB_BPT;
	80	KDB_STATE_SET(SSBPT);
	81	break;
	82	}
	83	}
	84	}
	85
	86	if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
	87	ks->signo == SIGTRAP) {
	88	reason = KDB_REASON_SSTEP;
	89	db_result = KDB_DB_BPT;
	90	}
	91	/* Set initial kdb state variables */
	92	KDB_STATE_CLEAR(KGDB_TRANS);
495363d3	93	kdb_initial_cpu = atomic_read(&kgdb_active);
5d5314d6 JW	94	kdb_current_task = kgdb_info[ks->cpu].task;
	95	kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
	96	/* Remove any breakpoints as needed by kdb and clear single step */
	97	kdb_bp_remove();
	98	KDB_STATE_CLEAR(DOING_SS);
	99	KDB_STATE_CLEAR(DOING_SSB);
f5316b4a	100	KDB_STATE_SET(PAGER);
5d5314d6 JW	101	/* zero out any offline cpu data */
	102	for_each_present_cpu(i) {
	103	if (!cpu_online(i)) {
	104	kgdb_info[i].debuggerinfo = NULL;
	105	kgdb_info[i].task = NULL;
	106	}
	107	}
	108	if (ks->err_code == DIE_OOPS \|\| reason == KDB_REASON_OOPS) {
	109	ks->pass_exception = 1;
	110	KDB_FLAG_SET(CATASTROPHIC);
	111	}
5d5314d6 JW	112	if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
	113	KDB_STATE_CLEAR(SSBPT);
	114	KDB_STATE_CLEAR(DOING_SS);
	115	} else {
	116	/* Start kdb main loop */
	117	error = kdb_main_loop(KDB_REASON_ENTER, reason,
	118	ks->err_code, db_result, ks->linux_regs);
	119	}
	120	/*
	121	* Upon exit from the kdb main loop setup break points and restart
	122	* the system based on the requested continue state
	123	*/
	124	kdb_initial_cpu = -1;
	125	kdb_current_task = NULL;
	126	kdb_current_regs = NULL;
f5316b4a	127	KDB_STATE_CLEAR(PAGER);
5d5314d6 JW	128	kdbnearsym_cleanup();
5d5314d6 JW	129	if (error == KDB_CMD_KGDB) {
d613d828	130	if (KDB_STATE(DOING_KGDB))
5d5314d6	131	KDB_STATE_CLEAR(DOING_KGDB);
5d5314d6 JW	132	return DBG_PASS_EVENT;
	133	}
	134	kdb_bp_install(ks->linux_regs);
	135	dbg_activate_sw_breakpoints();
	136	/* Set the exit state to a single step or a continue */
	137	if (KDB_STATE(DOING_SS))
	138	gdbstub_state(ks, "s");
	139	else
	140	gdbstub_state(ks, "c");
	141
	142	KDB_FLAG_CLEAR(CATASTROPHIC);
	143
	144	/* Invoke arch specific exception handling prior to system resume */
	145	kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
	146	if (ks->pass_exception)
	147	kgdb_info[ks->cpu].ret_state = 1;
	148	if (error == KDB_CMD_CPU) {
	149	KDB_STATE_SET(REENTRY);
	150	/*
	151	* Force clear the single step bit because kdb emulates this
	152	* differently vs the gdbstub
	153	*/
	154	kgdb_single_step = 0;
	155	dbg_deactivate_sw_breakpoints();
	156	return DBG_SWITCH_CPU_EVENT;
	157	}
	158	return kgdb_info[ks->cpu].ret_state;
	159	}
	160
f679c498 JW	161	void kdb_gdb_state_pass(char *buf)
	162	{
	163	gdbstub_state(kdb_ks, buf);
	164	}