/**************************************************************************
*                                                                         *
* Copyright (c) International Business Machines Corp., 2005               *
*                                                                         *
* 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.                                     *
*                                                                         *
* This program is distributed in the hope that it will be useful, but     *
* WITHOUT ANY WARRANTY;  without even the implied warranty of             *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           *
* GNU General Public License for more details.                            *
*                                                                         *
* You should have received a copy of the GNU General Public License       *
* along with this program; if not, write to the Free Software             *
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *
*                                                                         *
* Author:  Guanglei Li (guanglei@cn.ibm.com)                              *
**************************************************************************/

/******************************************************
* Print the backtrace when:                           *
*  1. cpu is idle                                     *
*  2. when an io request is dispatched to scsi layer  *
*  ...                                                *
*                                                     *
*   To reduce overhead of symbol lookup,We only print *
* the address sequence of backtrace, for example:     *
*   c016844f c030fe6b                                 *
*                                                     *
*   Some post-processing is needed to get the symbol  *
* info associated with these addresses.               *
*                                                     *
*   We could use _stp_symbol_print to get such infor. *
*   For example:                                      *
*     _stp_symbol_print(0xc016844f);                  *
*                                                     *
*   The output should look like:                      *
*     0xc016844f : sys_read+0x2/0x62 []               *      
******************************************************/
probe addevent.backtrace
	= addevent.backtrace.cpuidle,
	addevent.backtrace.scsiioentry
{
}

/*
 Only applicable to SMP systems
 Refer to addevent.tskdispatch.cpuidle in tskdispatch.stp
*/
probe addevent.backtrace.cpuidle
	= kernel.inline("idle_balance")
{
	if(filter_by_pid() == 1 ) {
		log_tracedata_common(HOOKID_BT_CPUIDLE)
		log_backtrace_cpuidle()
	}
}

/* This failed to work on PPC64, refer to the comments
 in scsi.stp  */
probe addevent.backtrace.scsiioentry
	= module("scsi_mod").function("scsi_prep_fn")
{
	if(filter_by_pid() == 1 ) {
		log_tracedata_common(HOOKID_BT_IOREQ_TO_SCSI)
		log_backtrace_scsiioentry()
	}
}

function log_backtrace_cpuidle()
%{
	/* print the backtrace without symbols information */
	_stp_stack_sprint(_stp_stdout,CONTEXT->regs,0);
	_stp_printf("|"); 
%}

function log_backtrace_scsiioentry()
%{
	/* print the backtrace without symbols information */
	_stp_stack_sprint(_stp_stdout,CONTEXT->regs,0);
	_stp_printf("|"); 
%}