[deliverable/linux.git] / arch / hexagon / kernel / stacktrace.c

/*
 * Stacktrace support for Hexagon
 *
 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/thread_info.h>
#include <linux/module.h>

register unsigned long current_frame_pointer asm("r30");

struct stackframe {
	unsigned long fp;
	unsigned long rets;
};

/*
 * Save stack-backtrace addresses into a stack_trace buffer.
 */
void save_stack_trace(struct stack_trace *trace)
{
	unsigned long low, high;
	unsigned long fp;
	struct stackframe *frame;
	int skip = trace->skip;

	low = (unsigned long)task_stack_page(current);
	high = low + THREAD_SIZE;
	fp = current_frame_pointer;

	while (fp >= low && fp <= (high - sizeof(*frame))) {
		frame = (struct stackframe *)fp;

		if (skip) {
			skip--;
		} else {
			trace->entries[trace->nr_entries++] = frame->rets;
			if (trace->nr_entries >= trace->max_entries)
				break;
		}

		/*
		 * The next frame must be at a higher address than the
		 * current frame.
		 */
		low = fp + sizeof(*frame);
		fp = frame->fp;
	}
}
EXPORT_SYMBOL_GPL(save_stack_trace);
Commit	Line	Data
74d04d6f RK	1	/*
	2	* Stacktrace support for Hexagon
	3	*
e1858b2a	4	* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
74d04d6f RK	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 and
	8	* only version 2 as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	18	* 02110-1301, USA.
	19	*/
	20
	21	#include <linux/sched.h>
	22	#include <linux/stacktrace.h>
	23	#include <linux/thread_info.h>
	24	#include <linux/module.h>
	25
	26	register unsigned long current_frame_pointer asm("r30");
	27
	28	struct stackframe {
	29	unsigned long fp;
	30	unsigned long rets;
	31	};
	32
	33	/*
	34	* Save stack-backtrace addresses into a stack_trace buffer.
	35	*/
	36	void save_stack_trace(struct stack_trace *trace)
	37	{
	38	unsigned long low, high;
	39	unsigned long fp;
	40	struct stackframe *frame;
	41	int skip = trace->skip;
	42
	43	low = (unsigned long)task_stack_page(current);
	44	high = low + THREAD_SIZE;
	45	fp = current_frame_pointer;
	46
	47	while (fp >= low && fp <= (high - sizeof(*frame))) {
	48	frame = (struct stackframe *)fp;
	49
	50	if (skip) {
	51	skip--;
	52	} else {
	53	trace->entries[trace->nr_entries++] = frame->rets;
	54	if (trace->nr_entries >= trace->max_entries)
	55	break;
	56	}
	57
	58	/*
	59	* The next frame must be at a higher address than the
	60	* current frame.
	61	*/
	62	low = fp + sizeof(*frame);
	63	fp = frame->fp;
	64	}
	65	}
	66	EXPORT_SYMBOL_GPL(save_stack_trace);