| /* | 
 |  *  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/bug.h> | 
 | #include <linux/nmi.h> | 
 | #include <linux/sysfs.h> | 
 |  | 
 | #include <asm/stacktrace.h> | 
 |  | 
 | #include "dumpstack.h" | 
 |  | 
 |  | 
 | 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 + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]" | 
 | #endif | 
 | 	}; | 
 |  | 
 | int x86_is_stack_id(int id, char *name) | 
 | { | 
 | 	return x86_stack_ids[id - 1] == name; | 
 | } | 
 |  | 
 | 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; | 
 | } | 
 |  | 
 | /* | 
 |  * 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; | 
 |  | 
 | 	if (!task) | 
 | 		task = current; | 
 |  | 
 | 	if (!stack) { | 
 | 		unsigned long dummy; | 
 | 		stack = &dummy; | 
 | 		if (task && task != current) | 
 | 			stack = (unsigned long *)task->thread.sp; | 
 | 	} | 
 |  | 
 | #ifdef CONFIG_FRAME_POINTER | 
 | 	if (!bp) { | 
 | 		if (task == current) { | 
 | 			/* Grab bp right from our regs */ | 
 | 			get_bp(bp); | 
 | 		} else { | 
 | 			/* bp is the last reg pushed by switch_to */ | 
 | 			bp = *(unsigned long *) task->thread.sp; | 
 | 		} | 
 | 	} | 
 | #endif | 
 |  | 
 | 	/* | 
 | 	 * 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 = print_context_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 (stack >= irq_stack && stack < irq_stack_end) { | 
 | 				if (ops->stack(data, "IRQ") < 0) | 
 | 					break; | 
 | 				bp = print_context_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 = print_context_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 *stack; | 
 | 	int i; | 
 | 	const int cpu = smp_processor_id(); | 
 | 	unsigned long *irq_stack_end = | 
 | 		(unsigned long *)(per_cpu(irq_stack_ptr, cpu)); | 
 | 	unsigned long *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]); | 
 | 				printk(" <EOI> "); | 
 | 			} | 
 | 		} else { | 
 | 		if (((long) stack & (THREAD_SIZE-1)) == 0) | 
 | 			break; | 
 | 		} | 
 | 		if (i && ((i % STACKSLOTS_PER_LINE) == 0)) | 
 | 			printk("\n%s", log_lvl); | 
 | 		printk(" %016lx", *stack++); | 
 | 		touch_nmi_watchdog(); | 
 | 	} | 
 | 	printk("\n"); | 
 | 	show_trace_log_lvl(task, regs, sp, bp, log_lvl); | 
 | } | 
 |  | 
 | void show_registers(struct pt_regs *regs) | 
 | { | 
 | 	int i; | 
 | 	unsigned long sp; | 
 | 	const int cpu = smp_processor_id(); | 
 | 	struct task_struct *cur = current; | 
 |  | 
 | 	sp = regs->sp; | 
 | 	printk("CPU %d ", cpu); | 
 | 	__show_regs(regs, 1); | 
 | 	printk("Process %s (pid: %d, threadinfo %p, task %p)\n", | 
 | 		cur->comm, cur->pid, task_thread_info(cur), cur); | 
 |  | 
 | 	/* | 
 | 	 * 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_EMERG "Stack:\n"); | 
 | 		show_stack_log_lvl(NULL, regs, (unsigned long *)sp, | 
 | 				regs->bp, KERN_EMERG); | 
 |  | 
 | 		printk(KERN_EMERG "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)) { | 
 | 				printk(" Bad RIP value."); | 
 | 				break; | 
 | 			} | 
 | 			if (ip == (u8 *)regs->ip) | 
 | 				printk("<%02x> ", c); | 
 | 			else | 
 | 				printk("%02x ", c); | 
 | 		} | 
 | 	} | 
 | 	printk("\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; | 
 | } | 
 |  |