1 files changed, 134 insertions, 0 deletions
diff --git a/src/core/fnrec.c b/src/core/fnrec.c
new file mode 100644
index 000000000..c768c91d4
--- /dev/null
+++ b/src/core/fnrec.c
@@ -0,0 +1,134 @@
+/*
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <gpxe/init.h>
+#include <gpxe/uaccess.h>
+
+/** @file
+ *
+ * Function trace recorder for crash and hang debugging
+ *
+ */
+
+enum {
+	/** Constant for identifying valid trace buffers */
+	fnrec_magic = 'f' << 24 | 'n' << 16 | 'r' << 8 | 'e',
+
+	/** Trace buffer length */
+	fnrec_buffer_length = 4096 / sizeof ( unsigned long ),
+};
+
+/** A trace buffer */
+struct fnrec_buffer {
+	/** Constant for identifying valid trace buffers */
+	uint32_t magic;
+
+	/** Next trace buffer entry to fill */
+	uint32_t idx;
+
+	/** Function address trace buffer */
+	unsigned long data[fnrec_buffer_length];
+};
+
+/** 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;
+}
+
+/**
+ * Reset the trace buffer and clear entries
+ */
+static void fnrec_reset ( void ) {
+	memset ( fnrec_buffer, 0, sizeof ( *fnrec_buffer ) );
+	fnrec_buffer->magic = fnrec_magic;
+}
+
+/**
+ * Write a value to the end of the buffer if it is not a repetition
+ *
+ * @v l			Value to append
+ */
+static void fnrec_append_unique ( unsigned long l ) {
+	static unsigned long lastval;
+	uint32_t idx = fnrec_buffer->idx;
+
+	/* Avoid recording the same value repeatedly */
+	if ( l == lastval )
+		return;
+
+	fnrec_buffer->data[idx] = l;
+	fnrec_buffer->idx = ( idx + 1 ) % fnrec_buffer_length;
+	lastval = l;
+}
+
+/**
+ * Print the contents of the trace buffer in chronological order
+ */
+static void fnrec_dump ( void ) {
+	size_t i;
+
+	if ( !fnrec_is_valid() ) {
+		printf ( "fnrec buffer not found\n" );
+		return;
+	}
+
+	printf ( "fnrec buffer dump:\n" );
+	for ( i = 0; i < fnrec_buffer_length; i++ ) {
+		unsigned long l = fnrec_buffer->data[
+			( fnrec_buffer->idx + i ) % fnrec_buffer_length];
+		printf ( "%08lx%c", l, i % 8 == 7 ? '\n' : ' ' );
+	}
+}
+
+/**
+ * Function tracer initialisation function
+ */
+static void fnrec_init ( void ) {
+	/* Hardcoded to 17 MB */
+	fnrec_buffer = phys_to_virt ( 17 * 1024 * 1024 );
+	fnrec_dump();
+	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 __unused ) {
+	if ( fnrec_is_valid() )
+		fnrec_append_unique ( ( unsigned long ) called_fn );
+}
+
+void __cyg_profile_func_exit ( void *called_fn __unused, void *call_site __unused ) {
+}