1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Stack trace management functions
  4 *
  5 *  Copyright IBM Corp. 2006
 
  6 */
  7
 
 
  8#include <linux/stacktrace.h>
  9#include <linux/uaccess.h>
 10#include <linux/compat.h>
 11#include <asm/stacktrace.h>
 12#include <asm/unwind.h>
 13#include <asm/kprobes.h>
 14#include <asm/ptrace.h>
 15
 16void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
 17		     struct task_struct *task, struct pt_regs *regs)
 18{
 19	struct unwind_state state;
 20	unsigned long addr;
 21
 22	unwind_for_each_frame(&state, task, regs, 0) {
 23		addr = unwind_get_return_address(&state);
 24		if (!addr || !consume_entry(cookie, addr))
 25			break;
 26	}
 
 
 
 
 
 27}
 28
 29int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
 30			     void *cookie, struct task_struct *task)
 31{
 32	struct unwind_state state;
 33	unsigned long addr;
 34
 35	unwind_for_each_frame(&state, task, NULL, 0) {
 36		if (state.stack_info.type != STACK_TYPE_TASK)
 37			return -EINVAL;
 38
 39		if (state.regs)
 40			return -EINVAL;
 41
 42		addr = unwind_get_return_address(&state);
 43		if (!addr)
 44			return -EINVAL;
 45
 46#ifdef CONFIG_RETHOOK
 47		/*
 48		 * Mark stacktraces with krethook functions on them
 49		 * as unreliable.
 50		 */
 51		if (state.ip == (unsigned long)arch_rethook_trampoline)
 52			return -EINVAL;
 53#endif
 54
 55		if (!consume_entry(cookie, addr))
 56			return -EINVAL;
 57	}
 58
 59	/* Check for stack corruption */
 60	if (unwind_error(&state))
 61		return -EINVAL;
 62	return 0;
 63}
 64
 65void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
 66			  const struct pt_regs *regs)
 67{
 68	struct stack_frame_user __user *sf;
 69	unsigned long ip, sp;
 70	bool first = true;
 71
 72	if (is_compat_task())
 73		return;
 74	if (!consume_entry(cookie, instruction_pointer(regs)))
 75		return;
 76	sf = (void __user *)user_stack_pointer(regs);
 77	pagefault_disable();
 78	while (1) {
 79		if (__get_user(sp, &sf->back_chain))
 80			break;
 81		if (__get_user(ip, &sf->gprs[8]))
 82			break;
 83		if (ip & 0x1) {
 84			/*
 85			 * If the instruction address is invalid, and this
 86			 * is the first stack frame, assume r14 has not
 87			 * been written to the stack yet. Otherwise exit.
 88			 */
 89			if (first && !(regs->gprs[14] & 0x1))
 90				ip = regs->gprs[14];
 91			else
 92				break;
 93		}
 94		if (!consume_entry(cookie, ip))
 95			break;
 96		/* Sanity check: ABI requires SP to be aligned 8 bytes. */
 97		if (!sp || sp & 0x7)
 98			break;
 99		sf = (void __user *)sp;
100		first = false;
101	}
102	pagefault_enable();
103}

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Stack trace management functions
 4 *
 5 *  Copyright IBM Corp. 2006
 6 *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
 7 */
 8
 9#include <linux/sched.h>
10#include <linux/sched/debug.h>
11#include <linux/stacktrace.h>
12#include <linux/kallsyms.h>
13#include <linux/export.h>
14
15static int __save_address(void *data, unsigned long address, int nosched)
16{
17	struct stack_trace *trace = data;
18
19	if (nosched && in_sched_functions(address))
20		return 0;
21	if (trace->skip > 0) {
22		trace->skip--;
23		return 0;
 
 
 
 
 
24	}
25	if (trace->nr_entries < trace->max_entries) {
26		trace->entries[trace->nr_entries++] = address;
27		return 0;
28	}
29	return 1;
30}
31
32static int save_address(void *data, unsigned long address, int reliable)
 
33{
34	return __save_address(data, address, 0);
35}
36
37static int save_address_nosched(void *data, unsigned long address, int reliable)
38{
39	return __save_address(data, address, 1);
40}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
41
42void save_stack_trace(struct stack_trace *trace)
43{
44	unsigned long sp;
45
46	sp = current_stack_pointer();
47	dump_trace(save_address, trace, NULL, sp);
48	if (trace->nr_entries < trace->max_entries)
49		trace->entries[trace->nr_entries++] = ULONG_MAX;
50}
51EXPORT_SYMBOL_GPL(save_stack_trace);
52
53void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
54{
55	unsigned long sp;
56
57	sp = tsk->thread.ksp;
58	if (tsk == current)
59		sp = current_stack_pointer();
60	dump_trace(save_address_nosched, trace, tsk, sp);
61	if (trace->nr_entries < trace->max_entries)
62		trace->entries[trace->nr_entries++] = ULONG_MAX;
63}
64EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
65
66void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
67{
68	unsigned long sp;
69
70	sp = kernel_stack_pointer(regs);
71	dump_trace(save_address, trace, NULL, sp);
72	if (trace->nr_entries < trace->max_entries)
73		trace->entries[trace->nr_entries++] = ULONG_MAX;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
74}
75EXPORT_SYMBOL_GPL(save_stack_trace_regs);