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",
27 [ ESTACK_VC
] = "#VC",
28 [ ESTACK_VC2
] = "#VC2",
31 const char *stack_type_name(enum stack_type type
)
33 BUILD_BUG_ON(N_EXCEPTION_STACKS
!= 6);
35 if (type
== STACK_TYPE_IRQ
)
38 if (type
== STACK_TYPE_ENTRY
) {
40 * On 64-bit, we have a generic entry stack that we
41 * use for all the kernel entry points, including
44 return "ENTRY_TRAMPOLINE";
47 if (type
>= STACK_TYPE_EXCEPTION
&& type
<= STACK_TYPE_EXCEPTION_LAST
)
48 return exception_stack_names
[type
- STACK_TYPE_EXCEPTION
];
54 * struct estack_pages - Page descriptor for exception stacks
55 * @offs: Offset from the start of the exception stack area
56 * @size: Size of the exception stack
57 * @type: Type to store in the stack_info struct
65 #define EPAGERANGE(st) \
66 [PFN_DOWN(CEA_ESTACK_OFFS(st)) ... \
67 PFN_DOWN(CEA_ESTACK_OFFS(st) + CEA_ESTACK_SIZE(st) - 1)] = { \
68 .offs = CEA_ESTACK_OFFS(st), \
69 .size = CEA_ESTACK_SIZE(st), \
70 .type = STACK_TYPE_EXCEPTION + ESTACK_ ##st, }
73 * Array of exception stack page descriptors. If the stack is larger than
74 * PAGE_SIZE, all pages covering a particular stack will have the same
75 * info. The guard pages including the not mapped DB2 stack are zeroed
79 struct estack_pages estack_pages
[CEA_ESTACK_PAGES
] ____cacheline_aligned
= {
88 static __always_inline
bool in_exception_stack(unsigned long *stack
, struct stack_info
*info
)
90 unsigned long begin
, end
, stk
= (unsigned long)stack
;
91 const struct estack_pages
*ep
;
95 BUILD_BUG_ON(N_EXCEPTION_STACKS
!= 6);
97 begin
= (unsigned long)__this_cpu_read(cea_exception_stacks
);
99 * Handle the case where stack trace is collected _before_
100 * cea_exception_stacks had been initialized.
105 end
= begin
+ sizeof(struct cea_exception_stacks
);
106 /* Bail if @stack is outside the exception stack area. */
107 if (stk
< begin
|| stk
>= end
)
110 /* Calc page offset from start of exception stacks */
111 k
= (stk
- begin
) >> PAGE_SHIFT
;
112 /* Lookup the page descriptor */
113 ep
= &estack_pages
[k
];
118 begin
+= (unsigned long)ep
->offs
;
119 end
= begin
+ (unsigned long)ep
->size
;
120 regs
= (struct pt_regs
*)end
- 1;
122 info
->type
= ep
->type
;
123 info
->begin
= (unsigned long *)begin
;
124 info
->end
= (unsigned long *)end
;
125 info
->next_sp
= (unsigned long *)regs
->sp
;
129 static __always_inline
bool in_irq_stack(unsigned long *stack
, struct stack_info
*info
)
131 unsigned long *end
= (unsigned long *)this_cpu_read(hardirq_stack_ptr
);
132 unsigned long *begin
;
135 * @end points directly to the top most stack entry to avoid a -8
136 * adjustment in the stack switch hotpath. Adjust it back before
137 * calculating @begin.
140 begin
= end
- (IRQ_STACK_SIZE
/ sizeof(long));
143 * Due to the switching logic RSP can never be == @end because the
144 * final operation is 'popq %rsp' which means after that RSP points
145 * to the original stack and not to @end.
147 if (stack
< begin
|| stack
>= end
)
150 info
->type
= STACK_TYPE_IRQ
;
155 * The next stack pointer is stored at the top of the irq stack
156 * before switching to the irq stack. Actual stack entries are all
159 info
->next_sp
= (unsigned long *)*(end
- 1);
164 bool noinstr
get_stack_info_noinstr(unsigned long *stack
, struct task_struct
*task
,
165 struct stack_info
*info
)
167 if (in_task_stack(stack
, task
, info
))
173 if (in_exception_stack(stack
, info
))
176 if (in_irq_stack(stack
, info
))
179 if (in_entry_stack(stack
, info
))
185 int get_stack_info(unsigned long *stack
, struct task_struct
*task
,
186 struct stack_info
*info
, unsigned long *visit_mask
)
188 task
= task
? : current
;
193 if (!get_stack_info_noinstr(stack
, task
, info
))
197 * Make sure we don't iterate through any given stack more than once.
198 * If it comes up a second time then there's something wrong going on:
199 * just break out and report an unknown stack type.
202 if (*visit_mask
& (1UL << info
->type
)) {
204 printk_deferred_once(KERN_WARNING
"WARNING: stack recursion on stack type %d\n", info
->type
);
207 *visit_mask
|= 1UL << info
->type
;
213 info
->type
= STACK_TYPE_UNKNOWN
;