// SPDX-License-Identifier: GPL-2.0-only
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/*
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* SH specific backtracing code for oprofile
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*
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* Copyright 2007 STMicroelectronics Ltd.
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*
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* Author: Dave Peverley <dpeverley@mpc-data.co.uk>
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*
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* Based on ARM oprofile backtrace code by Richard Purdie and in turn, i386
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* oprofile backtrace code by John Levon, David Smith
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*/
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#include <linux/oprofile.h>
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#include <linux/sched.h>
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#include <linux/kallsyms.h>
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#include <linux/mm.h>
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#include <asm/unwinder.h>
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#include <asm/ptrace.h>
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#include <linux/uaccess.h>
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#include <asm/sections.h>
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#include <asm/stacktrace.h>
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static void backtrace_address(void *data, unsigned long addr, int reliable)
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{
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unsigned int *depth = data;
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if ((*depth)--)
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oprofile_add_trace(addr);
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}
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static struct stacktrace_ops backtrace_ops = {
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.address = backtrace_address,
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};
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/* Limit to stop backtracing too far. */
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static int backtrace_limit = 20;
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static unsigned long *
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user_backtrace(unsigned long *stackaddr, struct pt_regs *regs)
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{
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unsigned long buf_stack;
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/* Also check accessibility of address */
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if (!access_ok(stackaddr, sizeof(unsigned long)))
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return NULL;
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if (__copy_from_user_inatomic(&buf_stack, stackaddr, sizeof(unsigned long)))
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return NULL;
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/* Quick paranoia check */
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if (buf_stack & 3)
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return NULL;
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oprofile_add_trace(buf_stack);
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stackaddr++;
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return stackaddr;
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}
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void sh_backtrace(struct pt_regs * const regs, unsigned int depth)
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{
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unsigned long *stackaddr;
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/*
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* Paranoia - clip max depth as we could get lost in the weeds.
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*/
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if (depth > backtrace_limit)
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depth = backtrace_limit;
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stackaddr = (unsigned long *)kernel_stack_pointer(regs);
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if (!user_mode(regs)) {
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if (depth)
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unwind_stack(NULL, regs, stackaddr,
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&backtrace_ops, &depth);
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return;
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}
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while (depth-- && (stackaddr != NULL))
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stackaddr = user_backtrace(stackaddr, regs);
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}
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