1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4  * Copyright (C) 2013 Richard Weinberger <richard@nod.at>
5  * Copyright (C) 2014 Google Inc., Author: Daniel Walter <dwalter@google.com>
6  */
7 
8 #include <linux/kallsyms.h>
9 #include <linux/kernel.h>
10 #include <linux/sched.h>
11 #include <linux/stacktrace.h>
12 #include <linux/module.h>
13 #include <linux/uaccess.h>
14 #include <asm/stacktrace.h>
15 
dump_trace(struct task_struct * tsk,const struct stacktrace_ops * ops,void * data)16 void dump_trace(struct task_struct *tsk,
17 		const struct stacktrace_ops *ops,
18 		void *data)
19 {
20 	int reliable = 0;
21 	unsigned long *sp, bp, addr;
22 	struct pt_regs *segv_regs = tsk->thread.segv_regs;
23 	struct stack_frame *frame;
24 
25 	bp = get_frame_pointer(tsk, segv_regs);
26 	sp = get_stack_pointer(tsk, segv_regs);
27 
28 	frame = (struct stack_frame *)bp;
29 	while (((long) sp & (THREAD_SIZE-1)) != 0) {
30 		addr = READ_ONCE_NOCHECK(*sp);
31 		if (__kernel_text_address(addr)) {
32 			reliable = 0;
33 			if ((unsigned long) sp == bp + sizeof(long)) {
34 				frame = frame ? frame->next_frame : NULL;
35 				bp = (unsigned long)frame;
36 				reliable = 1;
37 			}
38 			ops->address(data, addr, reliable);
39 		}
40 		sp++;
41 	}
42 }
43 
save_addr(void * data,unsigned long address,int reliable)44 static void save_addr(void *data, unsigned long address, int reliable)
45 {
46 	struct stack_trace *trace = data;
47 
48 	if (!reliable)
49 		return;
50 	if (trace->nr_entries >= trace->max_entries)
51 		return;
52 
53 	trace->entries[trace->nr_entries++] = address;
54 }
55 
56 static const struct stacktrace_ops dump_ops = {
57 	.address = save_addr
58 };
59 
__save_stack_trace(struct task_struct * tsk,struct stack_trace * trace)60 static void __save_stack_trace(struct task_struct *tsk, struct stack_trace *trace)
61 {
62 	dump_trace(tsk, &dump_ops, trace);
63 }
64 
save_stack_trace(struct stack_trace * trace)65 void save_stack_trace(struct stack_trace *trace)
66 {
67 	__save_stack_trace(current, trace);
68 }
69 EXPORT_SYMBOL_GPL(save_stack_trace);
70 
save_stack_trace_tsk(struct task_struct * tsk,struct stack_trace * trace)71 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
72 {
73 	__save_stack_trace(tsk, trace);
74 }
75 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
76