--- /dev/null
+/*
+ * 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.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#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();
+ }
+}
Code Review / kvmfornfv.git / blobdiff