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[PATCH 1/4] Linux Kernel Markers : Architecture agnostic code.

From: Mathieu Desnoyers <mathieu dot desnoyers at polymtl dot ca>
To: linux-kernel at vger dot kernel dot org, Andrew Morton <akpm at osdl dot org>, Ingo Molnar <mingo at redhat dot com>, Greg Kroah-Hartman <gregkh at suse dot de>, Christoph Hellwig <hch at infradead dot org>
Cc: ltt-dev at shafik dot org, systemtap at sources dot redhat dot com, Douglas Niehaus <niehaus at eecs dot ku dot edu>, "Martin J. Bligh" <mbligh at mbligh dot org>, Thomas Gleixner <tglx at linutronix dot de>
Date: Wed, 20 Dec 2006 18:57:57 -0500
Subject: [PATCH 1/4] Linux Kernel Markers : Architecture agnostic code.
Linux Kernel Markers, architecture independant code.

This patch also includes non-optimized default behavior from asm-generic in each
architecture where the optimised support is not implemented.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -118,6 +118,14 @@ #define RODATA								\
         __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
 		*(__ksymtab_strings)					\
 	}								\
+	/* Kernel markers : pointers */					\
+	.markers : AT(ADDR(.markers) - LOAD_OFFSET) {			\
+		VMLINUX_SYMBOL(__start___markers) = .;			\
+		*(.markers)						\
+		VMLINUX_SYMBOL(__stop___markers) = .;			\
+	}								\
+	__end_rodata = .;						\
+	. = ALIGN(4096);						\
 									\
 	/* Built-in module parameters. */				\
 	__param : AT(ADDR(__param) - LOAD_OFFSET) {			\
--- /dev/null
+++ b/kernel/Kconfig.marker
@@ -0,0 +1,17 @@
+# Code markers configuration
+
+config MARKERS
+	bool "Activate markers"
+	select MODULES
+	default n
+	help
+	  Place an empty function call at each marker site. Can be
+	  dynamically changed for a probe function.
+
+config MARKERS_DISABLE_OPTIMIZATION
+	bool "Disable architecture specific marker optimization"
+	depends EMBEDDED
+	default n
+	help
+	  Disable code replacement jump optimisations. Especially useful if your
+	  code is in a read-only rom/flash.
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -356,6 +356,9 @@ #endif
 	/* The command line arguments (may be mangled).  People like
 	   keeping pointers to this stuff */
 	char *args;
+
+	const struct __mark_marker *markers;
+	unsigned int num_markers;
 };
 
 /* FIXME: It'd be nice to isolate modules during init, too, so they
@@ -469,6 +472,7 @@ extern void print_modules(void);
 struct device_driver;
 void module_add_driver(struct module *, struct device_driver *);
 void module_remove_driver(struct device_driver *);
+extern void list_modules(void);
 
 #else /* !CONFIG_MODULES... */
 #define EXPORT_SYMBOL(sym)
--- /dev/null
+++ b/include/linux/marker.h
@@ -0,0 +1,65 @@
+#ifndef _LINUX_MARKER_H
+#define _LINUX_MARKER_H
+
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing.
+ *
+ * Example :
+ *
+ * MARK(subsystem_event, "%d %s", someint, somestring);
+ * Where :
+ * - Subsystem is the name of your subsystem.
+ * - event is the name of the event to mark.
+ * - "%d %s" is the formatted string for printk.
+ * - someint is an integer.
+ * - somestring is a char *.
+ *
+ * - Dynamically overridable function call based on marker mechanism
+ *   from Frank Ch. Eigler <fche@redhat.com>.
+ * - Thanks to Jeremy Fitzhardinge <jeremy@goop.org> for his constructive
+ *   criticism about gcc optimization related issues.
+ *
+ * The marker mechanism supports multiple instances of the same marker.
+ * Markers can be put in inline functions, inlined static functions and
+ * unrolled loops.
+ *
+ * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#ifndef __ASSEMBLY__
+
+typedef void marker_probe_func(const char *fmt, ...);
+
+#ifndef CONFIG_MARKERS_DISABLE_OPTIMIZATION
+#include <asm/marker.h>
+#else
+#include <asm-generic/marker.h>
+#endif
+
+#define MARK_NOARGS " "
+#define MARK_MAX_FORMAT_LEN	1024
+
+#ifndef CONFIG_MARKERS
+#define MARK(name, format, args...) \
+		__mark_check_format(format, ## args)
+#endif
+
+static inline __attribute__ ((format (printf, 1, 2)))
+void __mark_check_format(const char *fmt, ...)
+{ }
+
+extern marker_probe_func __mark_empty_function;
+
+extern int marker_set_probe(const char *name, const char *format,
+				marker_probe_func *probe);
+
+extern int marker_remove_probe(marker_probe_func *probe);
+extern int marker_list_probe(marker_probe_func *probe);
+
+#endif
+#endif
--- /dev/null
+++ b/include/asm-arm/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-cris/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-frv/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-generic/marker.h
@@ -0,0 +1,49 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Generic header.
+ * 
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ *
+ * Note : the empty asm volatile with read constraint is used here instead of a
+ * "used" attribute to fix a gcc 4.1.x bug.
+ */
+
+struct __mark_marker_c {
+	const char *name;
+	marker_probe_func **call;
+	const char *format;
+} __attribute__((packed));
+
+struct __mark_marker {
+	const struct __mark_marker_c *cmark;
+	volatile char *enable;
+} __attribute__((packed));
+
+#ifdef CONFIG_MARKERS
+
+#define MARK(name, format, args...) \
+	do { \
+		static marker_probe_func *__mark_call_##name = \
+					__mark_empty_function; \
+		volatile static char __marker_enable_##name = 0; \
+		static const struct __mark_marker_c __mark_c_##name \
+			__attribute__((section(".markers.c"))) = \
+			{ #name, &__mark_call_##name, format } ; \
+		static const struct __mark_marker __mark_##name \
+			__attribute__((section(".markers"))) = \
+			{ &__mark_c_##name, &__marker_enable_##name } ; \
+		asm volatile ( "" : : "i" (&__mark_##name)); \
+		__mark_check_format(format, ## args); \
+		if (unlikely(__marker_enable_##name)) { \
+			preempt_disable(); \
+			(*__mark_call_##name)(format, ## args); \
+			preempt_enable_no_resched(); \
+		} \
+	} while (0)
+
+
+#define MARK_ENABLE_IMMEDIATE_OFFSET 0
+
+#endif
--- /dev/null
+++ b/include/asm-h8300/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-ia64/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-m32r/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-m68k/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-m68knommu/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-mips/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-parisc/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-ppc/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-s390/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-sh64/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-sh/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-sparc64/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-sparc/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-um/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-v850/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-x86_64/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
--- /dev/null
+++ b/include/asm-xtensa/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ * 
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>

OpenPGP public key:              http://krystal.dyndns.org:8080/key/compudj.gpg
Key fingerprint:     8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
References:
- [PATCH 0/4] Linux Kernel Markers
  - From: Mathieu Desnoyers
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