[mirror_ubuntu-zesty-kernel.git] / arch / s390 / kernel / stacktrace.c

/*
 * Stack trace management functions
 *
 *  Copyright IBM Corp. 2006
 *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
 */

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

static unsigned long save_context_stack(struct stack_trace *trace,
					unsigned long sp,
					unsigned long low,
					unsigned long high,
					int savesched)
{
	struct stack_frame *sf;
	struct pt_regs *regs;
	unsigned long addr;

	while(1) {
		if (sp < low || sp > high)
			return sp;
		sf = (struct stack_frame *)sp;
		while(1) {
			addr = sf->gprs[8];
			if (!trace->skip)
				trace->entries[trace->nr_entries++] = addr;
			else
				trace->skip--;
			if (trace->nr_entries >= trace->max_entries)
				return sp;
			low = sp;
			sp = sf->back_chain;
			if (!sp)
				break;
			if (sp <= low || sp > high - sizeof(*sf))
				return sp;
			sf = (struct stack_frame *)sp;
		}
		/* Zero backchain detected, check for interrupt frame. */
		sp = (unsigned long)(sf + 1);
		if (sp <= low || sp > high - sizeof(*regs))
			return sp;
		regs = (struct pt_regs *)sp;
		addr = regs->psw.addr;
		if (savesched || !in_sched_functions(addr)) {
			if (!trace->skip)
				trace->entries[trace->nr_entries++] = addr;
			else
				trace->skip--;
		}
		if (trace->nr_entries >= trace->max_entries)
			return sp;
		low = sp;
		sp = regs->gprs[15];
	}
}

static void __save_stack_trace(struct stack_trace *trace, unsigned long sp)
{
	unsigned long new_sp, frame_size;

	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
	new_sp = save_context_stack(trace, sp,
			S390_lowcore.panic_stack + frame_size - PAGE_SIZE,
			S390_lowcore.panic_stack + frame_size, 1);
	new_sp = save_context_stack(trace, new_sp,
			S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
			S390_lowcore.async_stack + frame_size, 1);
	save_context_stack(trace, new_sp,
			   S390_lowcore.thread_info,
			   S390_lowcore.thread_info + THREAD_SIZE, 1);
}

void save_stack_trace(struct stack_trace *trace)
{
	register unsigned long r15 asm ("15");
	unsigned long sp;

	sp = r15;
	__save_stack_trace(trace, sp);
	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace);

void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
	unsigned long sp, low, high;

	sp = tsk->thread.ksp;
	if (tsk == current) {
		/* Get current stack pointer. */
		asm volatile("la %0,0(15)" : "=a" (sp));
	}
	low = (unsigned long) task_stack_page(tsk);
	high = (unsigned long) task_pt_regs(tsk);
	save_context_stack(trace, sp, low, high, 0);
	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);

void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
	unsigned long sp;

	sp = kernel_stack_pointer(regs);
	__save_stack_trace(trace, sp);
	if (trace->nr_entries < trace->max_entries)
		trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_regs);
Commit	Line	Data
5bdc9b44	1	/*
5bdc9b44 HC	2	* Stack trace management functions
5bdc9b44 HC	3	*
a53c8fab	4	* Copyright IBM Corp. 2006
5bdc9b44 HC	5	* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
	6	*/
	7
	8	#include <linux/sched.h>
	9	#include <linux/stacktrace.h>
	10	#include <linux/kallsyms.h>
8de2ce86	11	#include <linux/module.h>
5bdc9b44	12
4d284cac	13	static unsigned long save_context_stack(struct stack_trace *trace,
4d284cac HC	14	unsigned long sp,
4d284cac HC	15	unsigned long low,
a3afe70b HC	16	unsigned long high,
a3afe70b HC	17	int savesched)
5bdc9b44 HC	18	{
	19	struct stack_frame *sf;
	20	struct pt_regs *regs;
	21	unsigned long addr;
	22
	23	while(1) {
5bdc9b44 HC	24	if (sp < low \|\| sp > high)
	25	return sp;
	26	sf = (struct stack_frame *)sp;
	27	while(1) {
9cb1ccec	28	addr = sf->gprs[8];
e90a2857	29	if (!trace->skip)
5bdc9b44 HC	30	trace->entries[trace->nr_entries++] = addr;
5bdc9b44 HC	31	else
e90a2857	32	trace->skip--;
5bdc9b44 HC	33	if (trace->nr_entries >= trace->max_entries)
	34	return sp;
	35	low = sp;
9cb1ccec	36	sp = sf->back_chain;
5bdc9b44 HC	37	if (!sp)
	38	break;
	39	if (sp <= low \|\| sp > high - sizeof(*sf))
	40	return sp;
	41	sf = (struct stack_frame *)sp;
	42	}
	43	/* Zero backchain detected, check for interrupt frame. */
	44	sp = (unsigned long)(sf + 1);
	45	if (sp <= low \|\| sp > high - sizeof(*regs))
	46	return sp;
	47	regs = (struct pt_regs *)sp;
9cb1ccec	48	addr = regs->psw.addr;
a3afe70b HC	49	if (savesched \|\| !in_sched_functions(addr)) {
	50	if (!trace->skip)
	51	trace->entries[trace->nr_entries++] = addr;
	52	else
	53	trace->skip--;
	54	}
5bdc9b44 HC	55	if (trace->nr_entries >= trace->max_entries)
	56	return sp;
	57	low = sp;
	58	sp = regs->gprs[15];
	59	}
	60	}
	61
66adce8f	62	static void __save_stack_trace(struct stack_trace *trace, unsigned long sp)
5bdc9b44	63	{
66adce8f	64	unsigned long new_sp, frame_size;
5bdc9b44	65
9900c48c	66	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
66adce8f	67	new_sp = save_context_stack(trace, sp,
9900c48c HC	68	S390_lowcore.panic_stack + frame_size - PAGE_SIZE,
9900c48c HC	69	S390_lowcore.panic_stack + frame_size, 1);
e90a2857	70	new_sp = save_context_stack(trace, new_sp,
9900c48c HC	71	S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
9900c48c HC	72	S390_lowcore.async_stack + frame_size, 1);
e90a2857	73	save_context_stack(trace, new_sp,
ab1b6f03	74	S390_lowcore.thread_info,
a3afe70b	75	S390_lowcore.thread_info + THREAD_SIZE, 1);
66adce8f HC	76	}
	77
	78	void save_stack_trace(struct stack_trace *trace)
	79	{
	80	register unsigned long r15 asm ("15");
	81	unsigned long sp;
	82
	83	sp = r15;
	84	__save_stack_trace(trace, sp);
f6331aac HC	85	if (trace->nr_entries < trace->max_entries)
f6331aac HC	86	trace->entries[trace->nr_entries++] = ULONG_MAX;
a3afe70b	87	}
7b4c9505	88	EXPORT_SYMBOL_GPL(save_stack_trace);
a3afe70b HC	89
	90	void save_stack_trace_tsk(struct task_struct tsk, struct stack_trace trace)
	91	{
	92	unsigned long sp, low, high;
	93
9cb1ccec	94	sp = tsk->thread.ksp;
665ca918 HC	95	if (tsk == current) {
	96	/* Get current stack pointer. */
	97	asm volatile("la %0,0(15)" : "=a" (sp));
	98	}
a3afe70b HC	99	low = (unsigned long) task_stack_page(tsk);
	100	high = (unsigned long) task_pt_regs(tsk);
	101	save_context_stack(trace, sp, low, high, 0);
	102	if (trace->nr_entries < trace->max_entries)
	103	trace->entries[trace->nr_entries++] = ULONG_MAX;
5bdc9b44	104	}
7b4c9505	105	EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
e0115875 PA	106
	107	void save_stack_trace_regs(struct pt_regs regs, struct stack_trace trace)
	108	{
	109	unsigned long sp;
	110
	111	sp = kernel_stack_pointer(regs);
	112	__save_stack_trace(trace, sp);
	113	if (trace->nr_entries < trace->max_entries)
	114	trace->entries[trace->nr_entries++] = ULONG_MAX;
	115	}
	116	EXPORT_SYMBOL_GPL(save_stack_trace_regs);