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kernel/linux-imx6_3.14.28/arch/powerpc/oprofile/backtrace.c 2.88 KB
6b13f685e   김민수   BSP 최초 추가
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  /**
   * Copyright (C) 2005 Brian Rogan <bcr6@cornell.edu>, IBM
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
  **/
  
  #include <linux/oprofile.h>
  #include <linux/sched.h>
  #include <asm/processor.h>
  #include <asm/uaccess.h>
  #include <asm/compat.h>
  
  #define STACK_SP(STACK)		*(STACK)
  
  #define STACK_LR64(STACK)	*((unsigned long *)(STACK) + 2)
  #define STACK_LR32(STACK)	*((unsigned int *)(STACK) + 1)
  
  #ifdef CONFIG_PPC64
  #define STACK_LR(STACK)		STACK_LR64(STACK)
  #else
  #define STACK_LR(STACK)		STACK_LR32(STACK)
  #endif
  
  static unsigned int user_getsp32(unsigned int sp, int is_first)
  {
  	unsigned int stack_frame[2];
  	void __user *p = compat_ptr(sp);
  
  	if (!access_ok(VERIFY_READ, p, sizeof(stack_frame)))
  		return 0;
  
  	/*
  	 * The most likely reason for this is that we returned -EFAULT,
  	 * which means that we've done all that we can do from
  	 * interrupt context.
  	 */
  	if (__copy_from_user_inatomic(stack_frame, p, sizeof(stack_frame)))
  		return 0;
  
  	if (!is_first)
  		oprofile_add_trace(STACK_LR32(stack_frame));
  
  	/*
  	 * We do not enforce increasing stack addresses here because
  	 * we may transition to a different stack, eg a signal handler.
  	 */
  	return STACK_SP(stack_frame);
  }
  
  #ifdef CONFIG_PPC64
  static unsigned long user_getsp64(unsigned long sp, int is_first)
  {
  	unsigned long stack_frame[3];
  
  	if (!access_ok(VERIFY_READ, (void __user *)sp, sizeof(stack_frame)))
  		return 0;
  
  	if (__copy_from_user_inatomic(stack_frame, (void __user *)sp,
  					sizeof(stack_frame)))
  		return 0;
  
  	if (!is_first)
  		oprofile_add_trace(STACK_LR64(stack_frame));
  
  	return STACK_SP(stack_frame);
  }
  #endif
  
  static unsigned long kernel_getsp(unsigned long sp, int is_first)
  {
  	unsigned long *stack_frame = (unsigned long *)sp;
  
  	if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
  		return 0;
  
  	if (!is_first)
  		oprofile_add_trace(STACK_LR(stack_frame));
  
  	/*
  	 * We do not enforce increasing stack addresses here because
  	 * we might be transitioning from an interrupt stack to a kernel
  	 * stack. validate_sp() is designed to understand this, so just
  	 * use it.
  	 */
  	return STACK_SP(stack_frame);
  }
  
  void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
  {
  	unsigned long sp = regs->gpr[1];
  	int first_frame = 1;
  
  	/* We ditch the top stackframe so need to loop through an extra time */
  	depth += 1;
  
  	if (!user_mode(regs)) {
  		while (depth--) {
  			sp = kernel_getsp(sp, first_frame);
  			if (!sp)
  				break;
  			first_frame = 0;
  		}
  	} else {
  #ifdef CONFIG_PPC64
  		if (!is_32bit_task()) {
  			while (depth--) {
  				sp = user_getsp64(sp, first_frame);
  				if (!sp)
  					break;
  				first_frame = 0;
  			}
  
  			return;
  		}
  #endif
  
  		while (depth--) {
  			sp = user_getsp32(sp, first_frame);
  			if (!sp)
  				break;
  			first_frame = 0;
  		}
  	}
  }