From 292f312aacb79ac129cad6d38e3ca95bfcc8ec95 Mon Sep 17 00:00:00 2001
From: compudj <compudj@04897980-b3bd-0310-b5e0-8ef037075253>
Date: Wed, 20 Sep 2006 23:07:12 +0000
Subject: [PATCH] add marker-loader

git-svn-id: http://ltt.polymtl.ca/svn@2126 04897980-b3bd-0310-b5e0-8ef037075253
---
 marker-loader/Makefile        | 21 ++++++++
 marker-loader/marker-loader.c | 92 +++++++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)
 create mode 100644 marker-loader/Makefile
 create mode 100644 marker-loader/marker-loader.c

diff --git a/marker-loader/Makefile b/marker-loader/Makefile
new file mode 100644
index 00000000..6523d116
--- /dev/null
+++ b/marker-loader/Makefile
@@ -0,0 +1,21 @@
+ifneq ($(KERNELRELEASE),)
+	obj-m += marker-loader.o
+else
+	KERNELDIR ?= /lib/modules/$(shell uname -r)/build
+	PWD := $(shell pwd)
+	KERNELRELEASE = $(shell cat $(KERNELDIR)/$(KBUILD_OUTPUT)/include/linux/version.h | sed -n 's/.*UTS_RELEASE.*\"\(.*\)\".*/\1/p')
+ifneq ($(INSTALL_MOD_PATH),)
+	DEPMOD_OPT := -b $(INSTALL_MOD_PATH)
+endif
+
+default:
+	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
+
+modules_install:
+	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install
+	if [ -f $(KERNELDIR)/$(KBUILD_OUTPUT)/System.map ] ; then /sbin/depmod -ae -F $(KERNELDIR)/$(KBUILD_OUTPUT)/System.map $(DEPMOD_OPT) $(KERNELRELEASE) ; fi
+
+
+clean:
+	$(MAKE) -C $(KERNELDIR) M=$(PWD) clean
+endif
diff --git a/marker-loader/marker-loader.c b/marker-loader/marker-loader.c
new file mode 100644
index 00000000..5686c210
--- /dev/null
+++ b/marker-loader/marker-loader.c
@@ -0,0 +1,92 @@
+/* marker-loader.c
+ *
+ * Marker Loader
+ *
+ * Loads a function at a marker call site.
+ *
+ * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <linux/marker.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+
+/* function to install */
+void do_mark1(const char *format, int value)
+{
+	printk("value is %d\n", value);
+}
+
+
+#define PROBE_NAME subsys_mark1
+
+#define CALL __mark_subsys_mark1_call
+#define JUMP_OVER __mark_subsys_mark1_jump_over
+#define JUMP_CALL __mark_subsys_mark1_jump_call
+#define JUMP_INLINE __mark_subsys_mark1_jump_inline
+
+static void *saved_over;
+
+static void **target_mark_call;
+static void **target_mark_jump_over;
+static void **target_mark_jump_call;
+static void **target_mark_jump_inline;
+
+void show_symbol_pointers(void)
+{
+	printk("Marker loader : Loading symbols...\n");
+	printk("  %s %p %p\n", __stringify(CALL), target_mark_call,
+		target_mark_call?*target_mark_call:0x0);
+	printk("  %s %p %p\n", __stringify(JUMP_OVER), target_mark_jump_over,
+		target_mark_jump_over?*target_mark_jump_over:0x0);
+	printk("  %s %p %p\n", __stringify(JUMP_CALL), target_mark_jump_call,
+		target_mark_jump_call?*target_mark_jump_call:0x0);
+	printk("  %s %p %p\n", __stringify(JUMP_INLINE), target_mark_jump_inline,
+		target_mark_jump_inline?*target_mark_jump_inline:0x0);
+}
+
+int mark_install_hook(void)
+{
+	target_mark_call = (void**)kallsyms_lookup_name(__stringify(CALL));
+	target_mark_jump_over = (void**)kallsyms_lookup_name(__stringify(JUMP_OVER));
+	target_mark_jump_call = (void**)kallsyms_lookup_name(__stringify(JUMP_CALL));
+	target_mark_jump_inline = (void**)kallsyms_lookup_name(__stringify(JUMP_INLINE));
+
+	show_symbol_pointers();
+	
+	if(!(target_mark_call && target_mark_jump_over && target_mark_jump_call && 
+		target_mark_jump_inline)) {
+		printk("Target symbols missing in kallsyms.\n");
+		return -EPERM;
+	}
+	
+	printk("Installing hook\n");
+	*target_mark_call = (void*)do_mark1;
+	saved_over = *target_mark_jump_over;
+	*target_mark_jump_over = *target_mark_jump_call;
+
+	return 0;
+}
+
+int init_module(void)
+{
+	return mark_install_hook();
+}
+
+void cleanup_module(void)
+{
+	printk("Removing hook\n");
+	*target_mark_jump_over = saved_over;
+	*target_mark_call = __mark_empty_function;
+
+	/* Wait for instrumentation functions to return before quitting */
+	synchronize_sched();
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Marker Loader");
+
-- 
2.34.1