1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * SH specific backtracing code for oprofile
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright 2007 STMicroelectronics Ltd.
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Author: Dave Peverley <dpeverley@mpc-data.co.uk>
8*4882a593Smuzhiyun *
9*4882a593Smuzhiyun * Based on ARM oprofile backtrace code by Richard Purdie and in turn, i386
10*4882a593Smuzhiyun * oprofile backtrace code by John Levon, David Smith
11*4882a593Smuzhiyun */
12*4882a593Smuzhiyun #include <linux/oprofile.h>
13*4882a593Smuzhiyun #include <linux/sched.h>
14*4882a593Smuzhiyun #include <linux/kallsyms.h>
15*4882a593Smuzhiyun #include <linux/mm.h>
16*4882a593Smuzhiyun #include <asm/unwinder.h>
17*4882a593Smuzhiyun #include <asm/ptrace.h>
18*4882a593Smuzhiyun #include <linux/uaccess.h>
19*4882a593Smuzhiyun #include <asm/sections.h>
20*4882a593Smuzhiyun #include <asm/stacktrace.h>
21*4882a593Smuzhiyun
backtrace_address(void * data,unsigned long addr,int reliable)22*4882a593Smuzhiyun static void backtrace_address(void *data, unsigned long addr, int reliable)
23*4882a593Smuzhiyun {
24*4882a593Smuzhiyun unsigned int *depth = data;
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun if ((*depth)--)
27*4882a593Smuzhiyun oprofile_add_trace(addr);
28*4882a593Smuzhiyun }
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun static struct stacktrace_ops backtrace_ops = {
31*4882a593Smuzhiyun .address = backtrace_address,
32*4882a593Smuzhiyun };
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun /* Limit to stop backtracing too far. */
35*4882a593Smuzhiyun static int backtrace_limit = 20;
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun static unsigned long *
user_backtrace(unsigned long * stackaddr,struct pt_regs * regs)38*4882a593Smuzhiyun user_backtrace(unsigned long *stackaddr, struct pt_regs *regs)
39*4882a593Smuzhiyun {
40*4882a593Smuzhiyun unsigned long buf_stack;
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun /* Also check accessibility of address */
43*4882a593Smuzhiyun if (!access_ok(stackaddr, sizeof(unsigned long)))
44*4882a593Smuzhiyun return NULL;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun if (__copy_from_user_inatomic(&buf_stack, stackaddr, sizeof(unsigned long)))
47*4882a593Smuzhiyun return NULL;
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun /* Quick paranoia check */
50*4882a593Smuzhiyun if (buf_stack & 3)
51*4882a593Smuzhiyun return NULL;
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun oprofile_add_trace(buf_stack);
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun stackaddr++;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun return stackaddr;
58*4882a593Smuzhiyun }
59*4882a593Smuzhiyun
sh_backtrace(struct pt_regs * const regs,unsigned int depth)60*4882a593Smuzhiyun void sh_backtrace(struct pt_regs * const regs, unsigned int depth)
61*4882a593Smuzhiyun {
62*4882a593Smuzhiyun unsigned long *stackaddr;
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun /*
65*4882a593Smuzhiyun * Paranoia - clip max depth as we could get lost in the weeds.
66*4882a593Smuzhiyun */
67*4882a593Smuzhiyun if (depth > backtrace_limit)
68*4882a593Smuzhiyun depth = backtrace_limit;
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun stackaddr = (unsigned long *)kernel_stack_pointer(regs);
71*4882a593Smuzhiyun if (!user_mode(regs)) {
72*4882a593Smuzhiyun if (depth)
73*4882a593Smuzhiyun unwind_stack(NULL, regs, stackaddr,
74*4882a593Smuzhiyun &backtrace_ops, &depth);
75*4882a593Smuzhiyun return;
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun while (depth-- && (stackaddr != NULL))
79*4882a593Smuzhiyun stackaddr = user_backtrace(stackaddr, regs);
80*4882a593Smuzhiyun }
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