[mirror_ubuntu-artful-kernel.git] / arch / x86 / kernel / dumpstack_64.c

/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
 */
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/kexec.h>
#include <linux/sysfs.h>
#include <linux/bug.h>
#include <linux/nmi.h>

#include <asm/stacktrace.h>


#define N_EXCEPTION_STACKS_END \
		(N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)

static char x86_stack_ids[][8] = {
		[ DEBUG_STACK-1			]	= "#DB",
		[ NMI_STACK-1			]	= "NMI",
		[ DOUBLEFAULT_STACK-1		]	= "#DF",
		[ STACKFAULT_STACK-1		]	= "#SS",
		[ MCE_STACK-1			]	= "#MC",
#if DEBUG_STKSZ > EXCEPTION_STKSZ
		[ N_EXCEPTION_STACKS ...
		  N_EXCEPTION_STACKS_END	]	= "#DB[?]"
#endif
};

static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
					 unsigned *usedp, char **idp)
{
	unsigned k;

	/*
	 * Iterate over all exception stacks, and figure out whether
	 * 'stack' is in one of them:
	 */
	for (k = 0; k < N_EXCEPTION_STACKS; k++) {
		unsigned long end = per_cpu(orig_ist, cpu).ist[k];
		/*
		 * Is 'stack' above this exception frame's end?
		 * If yes then skip to the next frame.
		 */
		if (stack >= end)
			continue;
		/*
		 * Is 'stack' above this exception frame's start address?
		 * If yes then we found the right frame.
		 */
		if (stack >= end - EXCEPTION_STKSZ) {
			/*
			 * Make sure we only iterate through an exception
			 * stack once. If it comes up for the second time
			 * then there's something wrong going on - just
			 * break out and return NULL:
			 */
			if (*usedp & (1U << k))
				break;
			*usedp |= 1U << k;
			*idp = x86_stack_ids[k];
			return (unsigned long *)end;
		}
		/*
		 * If this is a debug stack, and if it has a larger size than
		 * the usual exception stacks, then 'stack' might still
		 * be within the lower portion of the debug stack:
		 */
#if DEBUG_STKSZ > EXCEPTION_STKSZ
		if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
			unsigned j = N_EXCEPTION_STACKS - 1;

			/*
			 * Black magic. A large debug stack is composed of
			 * multiple exception stack entries, which we
			 * iterate through now. Dont look:
			 */
			do {
				++j;
				end -= EXCEPTION_STKSZ;
				x86_stack_ids[j][4] = '1' +
						(j - N_EXCEPTION_STACKS);
			} while (stack < end - EXCEPTION_STKSZ);
			if (*usedp & (1U << j))
				break;
			*usedp |= 1U << j;
			*idp = x86_stack_ids[j];
			return (unsigned long *)end;
		}
#endif
	}
	return NULL;
}

static inline int
in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
	     unsigned long *irq_stack_end)
{
	return (stack >= irq_stack && stack < irq_stack_end);
}

/*
 * x86-64 can have up to three kernel stacks:
 * process stack
 * interrupt stack
 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
 */

void dump_trace(struct task_struct *task, struct pt_regs *regs,
		unsigned long *stack, unsigned long bp,
		const struct stacktrace_ops *ops, void *data)
{
	const unsigned cpu = get_cpu();
	unsigned long *irq_stack_end =
		(unsigned long *)per_cpu(irq_stack_ptr, cpu);
	unsigned used = 0;
	struct thread_info *tinfo;
	int graph = 0;
	unsigned long dummy;

	if (!task)
		task = current;

	if (!stack) {
		if (regs)
			stack = (unsigned long *)regs->sp;
		else if (task != current)
			stack = (unsigned long *)task->thread.sp;
		else
			stack = &dummy;
	}

	if (!bp)
		bp = stack_frame(task, regs);
	/*
	 * Print function call entries in all stacks, starting at the
	 * current stack address. If the stacks consist of nested
	 * exceptions
	 */
	tinfo = task_thread_info(task);
	for (;;) {
		char *id;
		unsigned long *estack_end;
		estack_end = in_exception_stack(cpu, (unsigned long)stack,
						&used, &id);

		if (estack_end) {
			if (ops->stack(data, id) < 0)
				break;

			bp = ops->walk_stack(tinfo, stack, bp, ops,
					     data, estack_end, &graph);
			ops->stack(data, "<EOE>");
			/*
			 * We link to the next stack via the
			 * second-to-last pointer (index -2 to end) in the
			 * exception stack:
			 */
			stack = (unsigned long *) estack_end[-2];
			continue;
		}
		if (irq_stack_end) {
			unsigned long *irq_stack;
			irq_stack = irq_stack_end -
				(IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);

			if (in_irq_stack(stack, irq_stack, irq_stack_end)) {
				if (ops->stack(data, "IRQ") < 0)
					break;
				bp = ops->walk_stack(tinfo, stack, bp,
					ops, data, irq_stack_end, &graph);
				/*
				 * We link to the next stack (which would be
				 * the process stack normally) the last
				 * pointer (index -1 to end) in the IRQ stack:
				 */
				stack = (unsigned long *) (irq_stack_end[-1]);
				irq_stack_end = NULL;
				ops->stack(data, "EOI");
				continue;
			}
		}
		break;
	}

	/*
	 * This handles the process stack:
	 */
	bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
	put_cpu();
}
EXPORT_SYMBOL(dump_trace);

void
show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
		   unsigned long *sp, unsigned long bp, char *log_lvl)
{
	unsigned long *irq_stack_end;
	unsigned long *irq_stack;
	unsigned long *stack;
	int cpu;
	int i;

	preempt_disable();
	cpu = smp_processor_id();

	irq_stack_end	= (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
	irq_stack	= (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);

	/*
	 * Debugging aid: "show_stack(NULL, NULL);" prints the
	 * back trace for this cpu:
	 */
	if (sp == NULL) {
		if (task)
			sp = (unsigned long *)task->thread.sp;
		else
			sp = (unsigned long *)&sp;
	}

	stack = sp;
	for (i = 0; i < kstack_depth_to_print; i++) {
		if (stack >= irq_stack && stack <= irq_stack_end) {
			if (stack == irq_stack_end) {
				stack = (unsigned long *) (irq_stack_end[-1]);
				pr_cont(" <EOI> ");
			}
		} else {
		if (((long) stack & (THREAD_SIZE-1)) == 0)
			break;
		}
		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
			pr_cont("\n");
		pr_cont(" %016lx", *stack++);
		touch_nmi_watchdog();
	}
	preempt_enable();

	pr_cont("\n");
	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
}

void show_regs(struct pt_regs *regs)
{
	int i;
	unsigned long sp;

	sp = regs->sp;
	show_regs_print_info(KERN_DEFAULT);
	__show_regs(regs, 1);

	/*
	 * When in-kernel, we also print out the stack and code at the
	 * time of the fault..
	 */
	if (!user_mode(regs)) {
		unsigned int code_prologue = code_bytes * 43 / 64;
		unsigned int code_len = code_bytes;
		unsigned char c;
		u8 *ip;

		printk(KERN_DEFAULT "Stack:\n");
		show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
				   0, KERN_DEFAULT);

		printk(KERN_DEFAULT "Code: ");

		ip = (u8 *)regs->ip - code_prologue;
		if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
			/* try starting at IP */
			ip = (u8 *)regs->ip;
			code_len = code_len - code_prologue + 1;
		}
		for (i = 0; i < code_len; i++, ip++) {
			if (ip < (u8 *)PAGE_OFFSET ||
					probe_kernel_address(ip, c)) {
				pr_cont(" Bad RIP value.");
				break;
			}
			if (ip == (u8 *)regs->ip)
				pr_cont("<%02x> ", c);
			else
				pr_cont("%02x ", c);
		}
	}
	pr_cont("\n");
}

int is_valid_bugaddr(unsigned long ip)
{
	unsigned short ud2;

	if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
		return 0;

	return ud2 == 0x0b0f;
}
Commit	Line	Data
6fcbede3 AH	1	/*
	2	* Copyright (C) 1991, 1992 Linus Torvalds
	3	* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
	4	*/
	5	#include <linux/kallsyms.h>
	6	#include <linux/kprobes.h>
	7	#include <linux/uaccess.h>
6fcbede3 AH	8	#include <linux/hardirq.h>
	9	#include <linux/kdebug.h>
	10	#include <linux/module.h>
	11	#include <linux/ptrace.h>
	12	#include <linux/kexec.h>
b8030906	13	#include <linux/sysfs.h>
6fcbede3 AH	14	#include <linux/bug.h>
	15	#include <linux/nmi.h>
	16
	17	#include <asm/stacktrace.h>
	18
6fcbede3	19
b8030906 IM	20	#define N_EXCEPTION_STACKS_END \
b8030906 IM	21	(N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
0406ca6d FW	22
0406ca6d FW	23	static char x86_stack_ids[][8] = {
b8030906 IM	24	[ DEBUG_STACK-1 ] = "#DB",
	25	[ NMI_STACK-1 ] = "NMI",
	26	[ DOUBLEFAULT_STACK-1 ] = "#DF",
	27	[ STACKFAULT_STACK-1 ] = "#SS",
	28	[ MCE_STACK-1 ] = "#MC",
6fcbede3	29	#if DEBUG_STKSZ > EXCEPTION_STKSZ
b8030906 IM	30	[ N_EXCEPTION_STACKS ...
b8030906 IM	31	N_EXCEPTION_STACKS_END ] = "#DB[?]"
6fcbede3	32	#endif
b8030906	33	};
0406ca6d	34
0406ca6d	35	static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
b8030906	36	unsigned usedp, char *idp)
0406ca6d	37	{
6fcbede3 AH	38	unsigned k;
	39
	40	/*
	41	* Iterate over all exception stacks, and figure out whether
	42	* 'stack' is in one of them:
	43	*/
	44	for (k = 0; k < N_EXCEPTION_STACKS; k++) {
	45	unsigned long end = per_cpu(orig_ist, cpu).ist[k];
	46	/*
	47	* Is 'stack' above this exception frame's end?
	48	* If yes then skip to the next frame.
	49	*/
	50	if (stack >= end)
	51	continue;
	52	/*
	53	* Is 'stack' above this exception frame's start address?
	54	* If yes then we found the right frame.
	55	*/
	56	if (stack >= end - EXCEPTION_STKSZ) {
	57	/*
	58	* Make sure we only iterate through an exception
	59	* stack once. If it comes up for the second time
	60	* then there's something wrong going on - just
	61	* break out and return NULL:
	62	*/
	63	if (*usedp & (1U << k))
	64	break;
	65	*usedp \|= 1U << k;
0406ca6d	66	*idp = x86_stack_ids[k];
6fcbede3 AH	67	return (unsigned long *)end;
	68	}
	69	/*
	70	* If this is a debug stack, and if it has a larger size than
	71	* the usual exception stacks, then 'stack' might still
	72	* be within the lower portion of the debug stack:
	73	*/
	74	#if DEBUG_STKSZ > EXCEPTION_STKSZ
	75	if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
	76	unsigned j = N_EXCEPTION_STACKS - 1;
	77
	78	/*
	79	* Black magic. A large debug stack is composed of
	80	* multiple exception stack entries, which we
	81	* iterate through now. Dont look:
	82	*/
	83	do {
	84	++j;
	85	end -= EXCEPTION_STKSZ;
0406ca6d FW	86	x86_stack_ids[j][4] = '1' +
0406ca6d FW	87	(j - N_EXCEPTION_STACKS);
6fcbede3 AH	88	} while (stack < end - EXCEPTION_STKSZ);
	89	if (*usedp & (1U << j))
	90	break;
	91	*usedp \|= 1U << j;
0406ca6d	92	*idp = x86_stack_ids[j];
6fcbede3 AH	93	return (unsigned long *)end;
	94	}
	95	#endif
	96	}
	97	return NULL;
	98	}
	99
af2d8289 FW	100	static inline int
	101	in_irq_stack(unsigned long stack, unsigned long irq_stack,
	102	unsigned long *irq_stack_end)
	103	{
	104	return (stack >= irq_stack && stack < irq_stack_end);
	105	}
	106
6fcbede3 AH	107	/*
	108	* x86-64 can have up to three kernel stacks:
	109	* process stack
	110	* interrupt stack
	111	* severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
	112	*/
	113
e8e999cf NK	114	void dump_trace(struct task_struct task, struct pt_regs regs,
e8e999cf NK	115	unsigned long *stack, unsigned long bp,
6fcbede3 AH	116	const struct stacktrace_ops ops, void data)
	117	{
	118	const unsigned cpu = get_cpu();
26f80bd6 BG	119	unsigned long *irq_stack_end =
26f80bd6 BG	120	(unsigned long *)per_cpu(irq_stack_ptr, cpu);
6fcbede3 AH	121	unsigned used = 0;
6fcbede3 AH	122	struct thread_info *tinfo;
7ee991fb	123	int graph = 0;
2e5aa682	124	unsigned long dummy;
6fcbede3 AH	125
	126	if (!task)
	127	task = current;
	128
	129	if (!stack) {
47ce11a2 FW	130	if (regs)
47ce11a2 FW	131	stack = (unsigned long *)regs->sp;
d0caf292	132	else if (task != current)
6fcbede3	133	stack = (unsigned long *)task->thread.sp;
47ce11a2 FW	134	else
47ce11a2 FW	135	stack = &dummy;
6fcbede3 AH	136	}
6fcbede3 AH	137
e8e999cf NK	138	if (!bp)
e8e999cf NK	139	bp = stack_frame(task, regs);
6fcbede3 AH	140	/*
	141	* Print function call entries in all stacks, starting at the
	142	* current stack address. If the stacks consist of nested
	143	* exceptions
	144	*/
	145	tinfo = task_thread_info(task);
	146	for (;;) {
	147	char *id;
	148	unsigned long *estack_end;
	149	estack_end = in_exception_stack(cpu, (unsigned long)stack,
	150	&used, &id);
	151
	152	if (estack_end) {
	153	if (ops->stack(data, id) < 0)
	154	break;
	155
61c1917f FW	156	bp = ops->walk_stack(tinfo, stack, bp, ops,
61c1917f FW	157	data, estack_end, &graph);
6fcbede3 AH	158	ops->stack(data, "<EOE>");
	159	/*
	160	* We link to the next stack via the
	161	* second-to-last pointer (index -2 to end) in the
	162	* exception stack:
	163	*/
	164	stack = (unsigned long *) estack_end[-2];
	165	continue;
	166	}
26f80bd6 BG	167	if (irq_stack_end) {
	168	unsigned long *irq_stack;
	169	irq_stack = irq_stack_end -
	170	(IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
6fcbede3	171
af2d8289	172	if (in_irq_stack(stack, irq_stack, irq_stack_end)) {
6fcbede3 AH	173	if (ops->stack(data, "IRQ") < 0)
6fcbede3 AH	174	break;
61e67fb9	175	bp = ops->walk_stack(tinfo, stack, bp,
26f80bd6	176	ops, data, irq_stack_end, &graph);
6fcbede3 AH	177	/*
	178	* We link to the next stack (which would be
	179	* the process stack normally) the last
	180	* pointer (index -1 to end) in the IRQ stack:
	181	*/
26f80bd6 BG	182	stack = (unsigned long *) (irq_stack_end[-1]);
26f80bd6 BG	183	irq_stack_end = NULL;
6fcbede3 AH	184	ops->stack(data, "EOI");
	185	continue;
	186	}
	187	}
	188	break;
	189	}
	190
	191	/*
	192	* This handles the process stack:
	193	*/
61e67fb9	194	bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
6fcbede3 AH	195	put_cpu();
	196	}
	197	EXPORT_SYMBOL(dump_trace);
	198
878719e8	199	void
6fcbede3	200	show_stack_log_lvl(struct task_struct task, struct pt_regs regs,
e8e999cf	201	unsigned long sp, unsigned long bp, char log_lvl)
6fcbede3	202	{
67f2de0b IM	203	unsigned long *irq_stack_end;
67f2de0b IM	204	unsigned long *irq_stack;
6fcbede3	205	unsigned long *stack;
67f2de0b	206	int cpu;
6fcbede3	207	int i;
67f2de0b IM	208
	209	preempt_disable();
	210	cpu = smp_processor_id();
	211
	212	irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
	213	irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
6fcbede3 AH	214
6fcbede3 AH	215	/*
67f2de0b IM	216	* Debugging aid: "show_stack(NULL, NULL);" prints the
67f2de0b IM	217	* back trace for this cpu:
6fcbede3	218	*/
6fcbede3 AH	219	if (sp == NULL) {
	220	if (task)
	221	sp = (unsigned long *)task->thread.sp;
	222	else
	223	sp = (unsigned long *)&sp;
	224	}
	225
	226	stack = sp;
	227	for (i = 0; i < kstack_depth_to_print; i++) {
26f80bd6 BG	228	if (stack >= irq_stack && stack <= irq_stack_end) {
	229	if (stack == irq_stack_end) {
	230	stack = (unsigned long *) (irq_stack_end[-1]);
c767a54b	231	pr_cont(" <EOI> ");
6fcbede3 AH	232	}
	233	} else {
	234	if (((long) stack & (THREAD_SIZE-1)) == 0)
	235	break;
	236	}
8a541665	237	if (i && ((i % STACKSLOTS_PER_LINE) == 0))
c767a54b JP	238	pr_cont("\n");
c767a54b JP	239	pr_cont(" %016lx", *stack++);
6fcbede3 AH	240	touch_nmi_watchdog();
6fcbede3 AH	241	}
67f2de0b IM	242	preempt_enable();
67f2de0b IM	243
c767a54b	244	pr_cont("\n");
e8e999cf	245	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
6fcbede3 AH	246	}
6fcbede3 AH	247
57da8b96	248	void show_regs(struct pt_regs *regs)
6fcbede3 AH	249	{
	250	int i;
	251	unsigned long sp;
6fcbede3 AH	252
6fcbede3 AH	253	sp = regs->sp;
a43cb95d	254	show_regs_print_info(KERN_DEFAULT);
6fcbede3	255	__show_regs(regs, 1);
6fcbede3 AH	256
	257	/*
	258	* When in-kernel, we also print out the stack and code at the
	259	* time of the fault..
	260	*/
	261	if (!user_mode(regs)) {
	262	unsigned int code_prologue = code_bytes * 43 / 64;
	263	unsigned int code_len = code_bytes;
	264	unsigned char c;
	265	u8 *ip;
	266
b0f4c4b3	267	printk(KERN_DEFAULT "Stack:\n");
6fcbede3	268	show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
b0f4c4b3	269	0, KERN_DEFAULT);
6fcbede3	270
b0f4c4b3	271	printk(KERN_DEFAULT "Code: ");
6fcbede3 AH	272
	273	ip = (u8 *)regs->ip - code_prologue;
	274	if (ip < (u8 *)PAGE_OFFSET \|\| probe_kernel_address(ip, c)) {
8a541665	275	/* try starting at IP */
6fcbede3 AH	276	ip = (u8 *)regs->ip;
	277	code_len = code_len - code_prologue + 1;
	278	}
	279	for (i = 0; i < code_len; i++, ip++) {
	280	if (ip < (u8 *)PAGE_OFFSET \|\|
	281	probe_kernel_address(ip, c)) {
c767a54b	282	pr_cont(" Bad RIP value.");
6fcbede3 AH	283	break;
	284	}
	285	if (ip == (u8 *)regs->ip)
c767a54b	286	pr_cont("<%02x> ", c);
6fcbede3	287	else
c767a54b	288	pr_cont("%02x ", c);
6fcbede3 AH	289	}
6fcbede3 AH	290	}
c767a54b	291	pr_cont("\n");
6fcbede3 AH	292	}
	293
	294	int is_valid_bugaddr(unsigned long ip)
	295	{
	296	unsigned short ud2;
	297
	298	if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
	299	return 0;
	300
	301	return ud2 == 0x0b0f;
	302	}