// SPDX-License-Identifier: GPL-2.0/* *  Copyright (C) 1991, 1992  Linus Torvalds *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs */#include <linux/sched/debug.h>#include <linux/kallsyms.h>#include <linux/kprobes.h>#include <linux/uaccess.h>#include <linux/hardirq.h>#include <linux/kdebug.h>#include <linux/export.h>#include <linux/ptrace.h>#include <linux/kexec.h>#include <linux/sysfs.h>#include <linux/bug.h>#include <linux/nmi.h> #include <asm/cpu_entry_area.h>#include <asm/stacktrace.h> static const char * const exception_stack_names[] = {		[ ESTACK_DF	]	= "#DF",		[ ESTACK_NMI	]	= "NMI",		[ ESTACK_DB	]	= "#DB",		[ ESTACK_MCE	]	= "#MC",}; const char *stack_type_name(enum stack_type type){	BUILD_BUG_ON(N_EXCEPTION_STACKS != 4); 	if (type == STACK_TYPE_IRQ)		return "IRQ"; 	if (type == STACK_TYPE_ENTRY) {		/*		 * On 64-bit, we have a generic entry stack that we		 * use for all the kernel entry points, including		 * SYSENTER.		 */		return "ENTRY_TRAMPOLINE";	} 	if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)		return exception_stack_names[type - STACK_TYPE_EXCEPTION]; 	return NULL;} /** * struct estack_pages - Page descriptor for exception stacks * @offs:	Offset from the start of the exception stack area * @size:	Size of the exception stack * @type:	Type to store in the stack_info struct */struct estack_pages {	u32	offs;	u16	size;	u16	type;}; #define EPAGERANGE(st)							\	[PFN_DOWN(CEA_ESTACK_OFFS(st)) ...				\	 PFN_DOWN(CEA_ESTACK_OFFS(st) + CEA_ESTACK_SIZE(st) - 1)] = {	\		.offs	= CEA_ESTACK_OFFS(st),				\		.size	= CEA_ESTACK_SIZE(st),				\		.type	= STACK_TYPE_EXCEPTION + ESTACK_ ##st, } /* * Array of exception stack page descriptors. If the stack is larger than * PAGE_SIZE, all pages covering a particular stack will have the same * info. The guard pages including the not mapped DB2 stack are zeroed * out. */static conststruct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = {	EPAGERANGE(DF),	EPAGERANGE(NMI),	EPAGERANGE(DB),	EPAGERANGE(MCE),}; static bool in_exception_stack(unsigned long *stack, struct stack_info *info){	unsigned long begin, end, stk = (unsigned long)stack;	const struct estack_pages *ep;	struct pt_regs *regs;	unsigned int k; 	BUILD_BUG_ON(N_EXCEPTION_STACKS != 4); 	begin = (unsigned long)__this_cpu_read(cea_exception_stacks);	/*	 * Handle the case where stack trace is collected _before_	 * cea_exception_stacks had been initialized.	 */	if (!begin)		return false; 	end = begin + sizeof(struct cea_exception_stacks);	/* Bail if @stack is outside the exception stack area. */	if (stk < begin || stk >= end)		return false; 	/* Calc page offset from start of exception stacks */	k = (stk - begin) >> PAGE_SHIFT;	/* Lookup the page descriptor */	ep = &estack_pages[k];	/* Guard page? */	if (!ep->size)		return false; 	begin += (unsigned long)ep->offs;	end = begin + (unsigned long)ep->size;	regs = (struct pt_regs *)end - 1; 	info->type	= ep->type;	info->begin	= (unsigned long *)begin;	info->end	= (unsigned long *)end;	info->next_sp	= (unsigned long *)regs->sp;	return true;} static bool in_irq_stack(unsigned long *stack, struct stack_info *info){	unsigned long *end   = (unsigned long *)this_cpu_read(hardirq_stack_ptr);	unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long)); 	/*	 * This is a software stack, so 'end' can be a valid stack pointer.	 * It just means the stack is empty.	 */	if (stack < begin || stack >= end)		return false; 	info->type	= STACK_TYPE_IRQ;	info->begin	= begin;	info->end	= end; 	/*	 * The next stack pointer is the first thing pushed by the entry code	 * after switching to the irq stack.	 */	info->next_sp = (unsigned long *)*(end - 1); 	return true;} int get_stack_info(unsigned long *stack, struct task_struct *task,		   struct stack_info *info, unsigned long *visit_mask){	if (!stack)		goto unknown; 	task = task ? : current; 	if (in_task_stack(stack, task, info))		goto recursion_check; 	if (task != current)		goto unknown; 	if (in_exception_stack(stack, info))		goto recursion_check; 	if (in_irq_stack(stack, info))		goto recursion_check; 	if (in_entry_stack(stack, info))		goto recursion_check; 	goto unknown; recursion_check:	/*	 * Make sure we don't iterate through any given stack more than once.	 * If it comes up a second time then there's something wrong going on:	 * just break out and report an unknown stack type.	 */	if (visit_mask) {		if (*visit_mask & (1UL << info->type)) {			if (task == current)				printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);			goto unknown;		}		*visit_mask |= 1UL << info->type;	} 	return 0; unknown:	info->type = STACK_TYPE_UNKNOWN;	return -EINVAL;}