sh: oprofile: Backtrace support. (40a8b421) · Commits · 戴 / test

arch/sh/oprofile/backtrace.c

0 → 100644

+118 −0

Original line number	Diff line number	Diff line
		/*
		* SH specific backtracing code for oprofile
		*
		* Copyright 2007 STMicroelectronics Ltd.
		*
		* Author: Dave Peverley <dpeverley@mpc-data.co.uk>
		*
		* Based on ARM oprofile backtrace code by Richard Purdie and in turn, i386
		* oprofile backtrace code by John Levon, David Smith
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 as
		* published by the Free Software Foundation.
		*
		*/
		#include <linux/oprofile.h>
		#include <linux/sched.h>
		#include <linux/kallsyms.h>
		#include <linux/mm.h>
		#include <asm/ptrace.h>
		#include <asm/uaccess.h>
		#include <asm/sections.h>

		/* Limit to stop backtracing too far. */
		static int backtrace_limit = 20;

		static unsigned long *
		user_backtrace(unsigned long stackaddr, struct pt_regs regs)
		{
		unsigned long buf_stack;

		/* Also check accessibility of address */
		if (!access_ok(VERIFY_READ, stackaddr, sizeof(unsigned long)))
		return NULL;

		if (__copy_from_user_inatomic(&buf_stack, stackaddr, sizeof(unsigned long)))
		return NULL;

		/* Quick paranoia check */
		if (buf_stack & 3)
		return NULL;

		oprofile_add_trace(buf_stack);

		stackaddr++;

		return stackaddr;
		}

		/*
		* \| \| /\ Higher addresses
		* \| \|
		* --------------- stack base (address of current_thread_info)
		* \| thread info \|
		* . .
		* \| stack \|
		* --------------- saved regs->regs[15] value if valid
		* . .
		* --------------- struct pt_regs stored on stack (struct pt_regs *)
		* \| \|
		* . .
		* \| \|
		* --------------- ???
		* \| \|
		* \| \| \/ Lower addresses
		*
		* Thus, &pt_regs <-> stack base restricts the valid(ish) fp values
		*/
		static int valid_kernel_stack(unsigned long stackaddr, struct pt_regs regs)
		{
		unsigned long stack = (unsigned long)regs;
		unsigned long stack_base = (stack & ~(THREAD_SIZE - 1)) + THREAD_SIZE;

		return ((unsigned long)stackaddr > stack) && ((unsigned long)stackaddr < stack_base);
		}

		static unsigned long *
		kernel_backtrace(unsigned long stackaddr, struct pt_regs regs)
		{
		unsigned long addr;

		/*
		* If not a valid kernel address, keep going till we find one
		* or the SP stops being a valid address.
		*/
		do {
		addr = *stackaddr++;

		if (__kernel_text_address(addr)) {
		oprofile_add_trace(addr);
		break;
		}
		} while (valid_kernel_stack(stackaddr, regs));

		return stackaddr;
		}

		void sh_backtrace(struct pt_regs * const regs, unsigned int depth)
		{
		unsigned long *stackaddr;

		/*
		* Paranoia - clip max depth as we could get lost in the weeds.
		*/
		if (depth > backtrace_limit)
		depth = backtrace_limit;

		stackaddr = (unsigned long *)regs->regs[15];
		if (!user_mode(regs)) {
		while (depth-- && valid_kernel_stack(stackaddr, regs))
		stackaddr = kernel_backtrace(stackaddr, regs);

		return;
		}

		while (depth-- && (stackaddr != NULL))
		stackaddr = user_backtrace(stackaddr, regs);
		}

arch/sh/oprofile/common.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,8 @@ static struct op_sh_model *model;

		static struct op_counter_config ctr[20];

		extern void sh_backtrace(struct pt_regs * const regs, unsigned int depth);

		static int op_sh_setup(void)
		{
		/* Pre-compute the values to stuff in the hardware registers. */
		@@ -85,6 +87,13 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
		struct op_sh_model *lmodel = NULL;
		int ret;

		/*
		* Always assign the backtrace op. If the counter initialization
		* fails, we fall back to the timer which will still make use of
		* this.
		*/
		ops->backtrace = sh_backtrace;

		switch (current_cpu_data.type) {
		/* SH-4 types */
		case CPU_SH7750:

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