1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
6 #include <linux/sched/debug.h>
7 #include <linux/kallsyms.h>
8 #include <linux/kprobes.h>
9 #include <linux/uaccess.h>
10 #include <linux/hardirq.h>
11 #include <linux/kdebug.h>
12 #include <linux/export.h>
13 #include <linux/ptrace.h>
14 #include <linux/kexec.h>
15 #include <linux/sysfs.h>
16 #include <linux/bug.h>
17 #include <linux/nmi.h>
19 #include <asm/cpu_entry_area.h>
20 #include <asm/stacktrace.h>
22 static const char * const exception_stack_names[] = {
23 [ ESTACK_DF ] = "#DF",
24 [ ESTACK_NMI ] = "NMI",
25 [ ESTACK_DB ] = "#DB",
26 [ ESTACK_MCE ] = "#MC",
29 const char *stack_type_name(enum stack_type type)
31 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
33 if (type == STACK_TYPE_IRQ)
36 if (type == STACK_TYPE_ENTRY) {
38 * On 64-bit, we have a generic entry stack that we
39 * use for all the kernel entry points, including
42 return "ENTRY_TRAMPOLINE";
45 if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
46 return exception_stack_names[type - STACK_TYPE_EXCEPTION];
52 * struct estack_pages - Page descriptor for exception stacks
53 * @offs: Offset from the start of the exception stack area
54 * @size: Size of the exception stack
55 * @type: Type to store in the stack_info struct
63 #define EPAGERANGE(st) \
64 [PFN_DOWN(CEA_ESTACK_OFFS(st)) ... \
65 PFN_DOWN(CEA_ESTACK_OFFS(st) + CEA_ESTACK_SIZE(st) - 1)] = { \
66 .offs = CEA_ESTACK_OFFS(st), \
67 .size = CEA_ESTACK_SIZE(st), \
68 .type = STACK_TYPE_EXCEPTION + ESTACK_ ##st, }
71 * Array of exception stack page descriptors. If the stack is larger than
72 * PAGE_SIZE, all pages covering a particular stack will have the same
73 * info. The guard pages including the not mapped DB2 stack are zeroed
77 struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = {
84 static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
86 unsigned long begin, end, stk = (unsigned long)stack;
87 const struct estack_pages *ep;
91 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
93 begin = (unsigned long)__this_cpu_read(cea_exception_stacks);
95 * Handle the case where stack trace is collected _before_
96 * cea_exception_stacks had been initialized.
101 end = begin + sizeof(struct cea_exception_stacks);
102 /* Bail if @stack is outside the exception stack area. */
103 if (stk < begin || stk >= end)
106 /* Calc page offset from start of exception stacks */
107 k = (stk - begin) >> PAGE_SHIFT;
108 /* Lookup the page descriptor */
109 ep = &estack_pages[k];
114 begin += (unsigned long)ep->offs;
115 end = begin + (unsigned long)ep->size;
116 regs = (struct pt_regs *)end - 1;
118 info->type = ep->type;
119 info->begin = (unsigned long *)begin;
120 info->end = (unsigned long *)end;
121 info->next_sp = (unsigned long *)regs->sp;
125 static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
127 unsigned long *end = (unsigned long *)this_cpu_read(hardirq_stack_ptr);
128 unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
131 * This is a software stack, so 'end' can be a valid stack pointer.
132 * It just means the stack is empty.
134 if (stack < begin || stack >= end)
137 info->type = STACK_TYPE_IRQ;
142 * The next stack pointer is the first thing pushed by the entry code
143 * after switching to the irq stack.
145 info->next_sp = (unsigned long *)*(end - 1);
150 int get_stack_info(unsigned long *stack, struct task_struct *task,
151 struct stack_info *info, unsigned long *visit_mask)
156 task = task ? : current;
158 if (in_task_stack(stack, task, info))
159 goto recursion_check;
164 if (in_exception_stack(stack, info))
165 goto recursion_check;
167 if (in_irq_stack(stack, info))
168 goto recursion_check;
170 if (in_entry_stack(stack, info))
171 goto recursion_check;
177 * Make sure we don't iterate through any given stack more than once.
178 * If it comes up a second time then there's something wrong going on:
179 * just break out and report an unknown stack type.
182 if (*visit_mask & (1UL << info->type)) {
184 printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
187 *visit_mask |= 1UL << info->type;
193 info->type = STACK_TYPE_UNKNOWN;