/* *  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 intin_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); voidshow_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;}