/*
* Copyright (C) 2010 Stefan Hajnoczi <stefanha@gmail.com>.
*
* 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 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ipxe/init.h>
#include <ipxe/uaccess.h>
#include <ipxe/io.h>
/** @file
*
* Function trace recorder for crash and hang debugging
*
*/
/** Constant for identifying valid trace buffers */
#define FNREC_MAGIC ( 'f' << 24 | 'n' << 16 | 'r' << 8 | 'e' )
/** Number of trace buffer entries */
#define FNREC_NUM_ENTRIES 4096
/** Trace buffer physical address
*
* Fixed at 17MB
*/
#define FNREC_PHYS_ADDRESS ( 17 * 1024 * 1024 )
/** A trace buffer entry */
struct fnrec_entry {
/** Called function address */
void *called_fn;
/** Call site */
void *call_site;
/** Entry count */
uint16_t entry_count;
/** Exit count */
uint16_t exit_count;
/** Checksum */
unsigned long checksum;
};
/** A trace buffer */
struct fnrec_buffer {
/** Constant for identifying valid trace buffers */
uint32_t magic;
/** Next trace buffer entry to fill */
unsigned int idx;
/** Trace buffer */
struct fnrec_entry data[FNREC_NUM_ENTRIES]
__attribute__ (( aligned ( 64 ) ));
};
/** The trace buffer */
static struct fnrec_buffer *fnrec_buffer;
/**
* Test whether the trace buffer is valid
*
* @ret is_valid Buffer is valid
*/
static int fnrec_is_valid ( void ) {
return ( fnrec_buffer && ( fnrec_buffer->magic == FNREC_MAGIC ) );
}
/**
* Invalidate the trace buffer
*
*/
static void fnrec_invalidate ( void ) {
fnrec_buffer->magic = 0;
}
/**
* Reset the trace buffer and clear entries
*/
static void fnrec_reset ( void ) {
memset ( fnrec_buffer, 0, sizeof ( *fnrec_buffer ) );
fnrec_buffer->magic = FNREC_MAGIC;
}
/**
* Append an entry to the trace buffer
*
* @v called_fn Called function
* @v call_site Call site
* @ret entry Trace buffer entry
*/
static struct fnrec_entry * fnrec_append ( void *called_fn, void *call_site ) {
struct fnrec_entry *entry;
/* Re-use existing entry, if possible */
entry = &fnrec_buffer->data[ fnrec_buffer->idx ];
if ( ( entry->called_fn == called_fn ) &&
( entry->call_site == call_site ) &&
( entry->entry_count >= entry->exit_count ) ) {
return entry;
}
/* Otherwise, create a new entry */
fnrec_buffer->idx = ( ( fnrec_buffer->idx + 1 ) % FNREC_NUM_ENTRIES );
entry = &fnrec_buffer->data[ fnrec_buffer->idx ];
entry->called_fn = called_fn;
entry->call_site = call_site;
entry->entry_count = 0;
entry->exit_count = 0;
entry->checksum = ( ( ( unsigned long ) called_fn ) ^
( ( unsigned long ) call_site ) );
return entry;
}
/**
* Print the contents of the trace buffer in chronological order
*/
static void fnrec_dump ( void ) {
struct fnrec_entry *entry;
unsigned int i;
unsigned int idx;
unsigned long checksum;
printf ( "fnrec buffer dump:\n" );
for ( i = 1 ; i <= FNREC_NUM_ENTRIES ; i++ ) {
idx = ( ( fnrec_buffer->idx + i ) % FNREC_NUM_ENTRIES );
entry = &fnrec_buffer->data[idx];
if ( ( entry->entry_count == 0 ) && ( entry->exit_count == 0 ) )
continue;
checksum = ( ( ( ( unsigned long ) entry->called_fn ) ^
( ( unsigned long ) entry->call_site ) ) +
entry->entry_count + entry->exit_count );
printf ( "%p %p %d %d", entry->called_fn, entry->call_site,
entry->entry_count, entry->exit_count );
if ( entry->checksum != checksum ) {
printf ( " (checksum wrong at phys %08lx)",
virt_to_phys ( entry ) );
}
printf ( "\n");
}
}
/**
* Function tracer initialisation function
*/
static void fnrec_init ( void ) {
fnrec_buffer = phys_to_virt ( FNREC_PHYS_ADDRESS );
if ( fnrec_is_valid() ) {
fnrec_invalidate();
fnrec_dump();
} else {
printf ( "fnrec buffer not found\n" );
}
fnrec_reset();
}
struct init_fn fnrec_init_fn __init_fn ( INIT_NORMAL ) = {
.initialise = fnrec_init,
};
/*
* These functions are called from every C function. The compiler inserts
* these calls when -finstrument-functions is used.
*/
void __cyg_profile_func_enter ( void *called_fn, void *call_site ) {
struct fnrec_entry *entry;
if ( fnrec_is_valid() ) {
entry = fnrec_append ( called_fn, call_site );
entry->entry_count++;
entry->checksum++;
mb();
}
}
void __cyg_profile_func_exit ( void *called_fn, void *call_site ) {
struct fnrec_entry *entry;
if ( fnrec_is_valid() ) {
entry = fnrec_append ( called_fn, call_site );
entry->exit_count++;
entry->checksum++;
mb();
}
}
