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 <asm/stacktrace.h>
10#include <asm/unwind.h>
11#include <asm/kprobes.h>
12
13void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
14		     struct task_struct *task, struct pt_regs *regs)
 
 
 
15{
16	struct unwind_state state;
 
17	unsigned long addr;
18
19	unwind_for_each_frame(&state, task, regs, 0) {
20		addr = unwind_get_return_address(&state);
21		if (!addr || !consume_entry(cookie, addr))
22			break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
23	}
24}
25
26int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
27			     void *cookie, struct task_struct *task)
28{
29	struct unwind_state state;
30	unsigned long addr;
31
32	unwind_for_each_frame(&state, task, NULL, 0) {
33		if (state.stack_info.type != STACK_TYPE_TASK)
34			return -EINVAL;
35
36		if (state.regs)
37			return -EINVAL;
38
39		addr = unwind_get_return_address(&state);
40		if (!addr)
41			return -EINVAL;
42
43#ifdef CONFIG_KPROBES
44		/*
45		 * Mark stacktraces with kretprobed functions on them
46		 * as unreliable.
47		 */
48		if (state.ip == (unsigned long)__kretprobe_trampoline)
49			return -EINVAL;
50#endif
51
52		if (!consume_entry(cookie, addr))
53			return -EINVAL;
54	}
55
56	/* Check for stack corruption */
57	if (unwind_error(&state))
58		return -EINVAL;
59	return 0;
 
 
60}

 
 1/*
 2 * Stack trace management functions
 3 *
 4 *  Copyright IBM Corp. 2006
 5 *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
 6 */
 7
 8#include <linux/sched.h>
 9#include <linux/stacktrace.h>
10#include <linux/kallsyms.h>
11#include <linux/module.h>
 
12
13static unsigned long save_context_stack(struct stack_trace *trace,
14					unsigned long sp,
15					unsigned long low,
16					unsigned long high,
17					int savesched)
18{
19	struct stack_frame *sf;
20	struct pt_regs *regs;
21	unsigned long addr;
22
23	while(1) {
24		sp &= PSW_ADDR_INSN;
25		if (sp < low || sp > high)
26			return sp;
27		sf = (struct stack_frame *)sp;
28		while(1) {
29			addr = sf->gprs[8] & PSW_ADDR_INSN;
30			if (!trace->skip)
31				trace->entries[trace->nr_entries++] = addr;
32			else
33				trace->skip--;
34			if (trace->nr_entries >= trace->max_entries)
35				return sp;
36			low = sp;
37			sp = sf->back_chain & PSW_ADDR_INSN;
38			if (!sp)
39				break;
40			if (sp <= low || sp > high - sizeof(*sf))
41				return sp;
42			sf = (struct stack_frame *)sp;
43		}
44		/* Zero backchain detected, check for interrupt frame. */
45		sp = (unsigned long)(sf + 1);
46		if (sp <= low || sp > high - sizeof(*regs))
47			return sp;
48		regs = (struct pt_regs *)sp;
49		addr = regs->psw.addr & PSW_ADDR_INSN;
50		if (savesched || !in_sched_functions(addr)) {
51			if (!trace->skip)
52				trace->entries[trace->nr_entries++] = addr;
53			else
54				trace->skip--;
55		}
56		if (trace->nr_entries >= trace->max_entries)
57			return sp;
58		low = sp;
59		sp = regs->gprs[15];
60	}
61}
62
63void save_stack_trace(struct stack_trace *trace)
 
64{
65	register unsigned long sp asm ("15");
66	unsigned long orig_sp, new_sp;
67
68	orig_sp = sp & PSW_ADDR_INSN;
69	new_sp = save_context_stack(trace, orig_sp,
70				    S390_lowcore.panic_stack - PAGE_SIZE,
71				    S390_lowcore.panic_stack, 1);
72	if (new_sp != orig_sp)
73		return;
74	new_sp = save_context_stack(trace, new_sp,
75				    S390_lowcore.async_stack - ASYNC_SIZE,
76				    S390_lowcore.async_stack, 1);
77	if (new_sp != orig_sp)
78		return;
79	save_context_stack(trace, new_sp,
80			   S390_lowcore.thread_info,
81			   S390_lowcore.thread_info + THREAD_SIZE, 1);
82}
83EXPORT_SYMBOL_GPL(save_stack_trace);
 
 
 
84
85void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
86{
87	unsigned long sp, low, high;
88
89	sp = tsk->thread.ksp & PSW_ADDR_INSN;
90	low = (unsigned long) task_stack_page(tsk);
91	high = (unsigned long) task_pt_regs(tsk);
92	save_context_stack(trace, sp, low, high, 0);
93	if (trace->nr_entries < trace->max_entries)
94		trace->entries[trace->nr_entries++] = ULONG_MAX;
95}
96EXPORT_SYMBOL_GPL(save_stack_trace_tsk);