[Patch 0/4][Djprobe] Djprobe update for linux-2.6.14-rc5-mm1

[Patch 0/4][Djprobe] Djprobe update for linux-2.6.14-rc5-mm1

[Masami Hiramatsu]

Hi,

I developed new four patches of djprobe for linux-2.6.14-rc5-mm1.
I took advices described below about previous patches in these
patches.

New features:
- separate djprobe code from */kprobe.{c,h}
- use hash table to find the djprobe instance in specified area.
- use wait_event() to wait for safety check worker.
- move some members of djprobe structure to arguments of
  register_djprobe() function.
- support lockless kprobe implementation.

TODO:
- support architecture transparent interface.
   (Djprobe interface emulated by kprobes)
- kprobe interoperability (coexistance in same address)
- support other architectures

patch 1:    Introduce a instruction slot management structure to
            handle different size slots.
patch 2:    Djprobe core patch.
patch 3:    Djprobe i386 patch.

Also, I developed a testing patch of bulk registration interface.

patch 4:    Testing patch of bulk interface for review.

If they are good enough, I will post first 3 patches (except the
bulk patch) to LKML.

Best Regards,

-- 
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: hiramatu@sdl.hitachi.co.jp

[Patch 1/4][Djprobe] Djprobe update for linux-2.6.14-rc5-mm1

[Masami Hiramatsu]

Hi,

This patch enables get_insn_slot() to handle slots
that have different size.
It needs for supporting djprobe on NX bit.

-- 
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: hiramatu@sdl.hitachi.co.jp

 include/linux/kprobes.h |    5 ++++
 kernel/kprobes.c        |   58 +++++++++++++++++++++++++++++++-----------------
 2 files changed, 43 insertions(+), 20 deletions(-)
diff -Narup linux-2.6.14-rc5-mm1/include/linux/kprobes.h linux-2.6.14-rc5-mm1.djp.1/include/linux/kprobes.h
--- linux-2.6.14-rc5-mm1/include/linux/kprobes.h	2005-10-25 11:29:02.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.1/include/linux/kprobes.h	2005-10-25 13:11:26.000000000 +0900
@@ -147,6 +147,11 @@ struct kretprobe_instance {
 	struct task_struct *task;
 };

+struct kprobe_insn_page_list {
+	struct hlist_head list;
+	int insn_size;		/* size of an instruction slot */
+};
+
 #ifdef CONFIG_KPROBES
 extern spinlock_t kretprobe_lock;
 extern int arch_prepare_kprobe(struct kprobe *p);
diff -Narup linux-2.6.14-rc5-mm1/kernel/kprobes.c linux-2.6.14-rc5-mm1.djp.1/kernel/kprobes.c
--- linux-2.6.14-rc5-mm1/kernel/kprobes.c	2005-10-25 11:29:02.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.1/kernel/kprobes.c	2005-10-25 13:13:58.000000000 +0900
@@ -58,44 +58,50 @@ static DEFINE_PER_CPU(struct kprobe *, k
  * stepping on the instruction on a vmalloced/kmalloced/data page
  * is a recipe for disaster
  */
-#define INSNS_PER_PAGE	(PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
+#define INSNS_PER_PAGE(size) (PAGE_SIZE/(size * sizeof(kprobe_opcode_t)))

 struct kprobe_insn_page {
 	struct hlist_node hlist;
 	kprobe_opcode_t *insns;		/* Page of instruction slots */
-	char slot_used[INSNS_PER_PAGE];
 	int nused;
+	char slot_used[1];
 };

-static struct hlist_head kprobe_insn_pages;
+static struct kprobe_insn_page_list kprobe_insn_pages = {
+	HLIST_HEAD_INIT, MAX_INSN_SIZE
+};

 /**
- * get_insn_slot() - Find a slot on an executable page for an instruction.
+ * __get_insn_slot() - Find a slot on an executable page for an instruction.
  * We allocate an executable page if there's no room on existing ones.
  */
-kprobe_opcode_t __kprobes *get_insn_slot(void)
+kprobe_opcode_t
+	__kprobes * __get_insn_slot(struct kprobe_insn_page_list *pages)
 {
 	struct kprobe_insn_page *kip;
 	struct hlist_node *pos;
+	int ninsns = INSNS_PER_PAGE(pages->insn_size);

-	hlist_for_each(pos, &kprobe_insn_pages) {
+	hlist_for_each(pos, &pages->list) {
 		kip = hlist_entry(pos, struct kprobe_insn_page, hlist);
-		if (kip->nused < INSNS_PER_PAGE) {
+		if (kip->nused < ninsns) {
 			int i;
-			for (i = 0; i < INSNS_PER_PAGE; i++) {
+			for (i = 0; i < ninsns; i++) {
 				if (!kip->slot_used[i]) {
 					kip->slot_used[i] = 1;
 					kip->nused++;
-					return kip->insns + (i * MAX_INSN_SIZE);
+					return kip->insns +
+					    (i * pages->insn_size);
 				}
 			}
 			/* Surprise!  No unused slots.  Fix kip->nused. */
-			kip->nused = INSNS_PER_PAGE;
+			kip->nused = ninsns;
 		}
 	}

-	/* All out of space.  Need to allocate a new page. Use slot 0.*/
-	kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
+	/* All out of space.  Need to allocate a new page. Use slot 0. */
+	kip = kmalloc(sizeof(struct kprobe_insn_page) +
+		    sizeof(char) * (ninsns - 1), GFP_ATOMIC);
 	if (!kip) {
 		return NULL;
 	}
@@ -111,23 +117,25 @@ kprobe_opcode_t __kprobes *get_insn_slot
 		return NULL;
 	}
 	INIT_HLIST_NODE(&kip->hlist);
-	hlist_add_head(&kip->hlist, &kprobe_insn_pages);
-	memset(kip->slot_used, 0, INSNS_PER_PAGE);
+	hlist_add_head(&kip->hlist, &pages->list);
+	memset(kip->slot_used, 0, ninsns);
 	kip->slot_used[0] = 1;
 	kip->nused = 1;
 	return kip->insns;
 }

-void __kprobes free_insn_slot(kprobe_opcode_t *slot)
+void __kprobes __free_insn_slot(struct kprobe_insn_page_list *pages,
+				kprobe_opcode_t * slot)
 {
 	struct kprobe_insn_page *kip;
 	struct hlist_node *pos;
+	int ninsns = INSNS_PER_PAGE(pages->insn_size);

-	hlist_for_each(pos, &kprobe_insn_pages) {
+	hlist_for_each(pos, &pages->list) {
 		kip = hlist_entry(pos, struct kprobe_insn_page, hlist);
 		if (kip->insns <= slot &&
-		    slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
-			int i = (slot - kip->insns) / MAX_INSN_SIZE;
+		    slot < kip->insns + (ninsns * pages->insn_size)) {
+			int i = (slot - kip->insns) / pages->insn_size;
 			kip->slot_used[i] = 0;
 			kip->nused--;
 			if (kip->nused == 0) {
@@ -138,10 +146,10 @@ void __kprobes free_insn_slot(kprobe_opc
 				 * next time somebody inserts a probe.
 				 */
 				hlist_del(&kip->hlist);
-				if (hlist_empty(&kprobe_insn_pages)) {
+				if (hlist_empty(&pages->list)) {
 					INIT_HLIST_NODE(&kip->hlist);
 					hlist_add_head(&kip->hlist,
-						&kprobe_insn_pages);
+						       &pages->list);
 				} else {
 					module_free(NULL, kip->insns);
 					kfree(kip);
@@ -152,6 +160,16 @@ void __kprobes free_insn_slot(kprobe_opc
 	}
 }

+kprobe_opcode_t __kprobes *get_insn_slot(void)
+{
+	return __get_insn_slot(&kprobe_insn_pages);
+}
+
+void __kprobes free_insn_slot(kprobe_opcode_t * slot)
+{
+	__free_insn_slot(&kprobe_insn_pages, slot);
+}
+
 /* We have preemption disabled.. so it is safe to use __ versions */
 static inline void set_kprobe_instance(struct kprobe *kp)
 {

[Patch 2/4][Djprobe] Djprobe update for linux-2.6.14-rc5-mm1

[Masami Hiramatsu]

Hi,

This patch is an architecture common code of djprobe.
The djprobe codes are separated from kprobe.{c,h}

-- 
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: hiramatu@sdl.hitachi.co.jp

 include/linux/djprobe.h |   80 +++++++++++++++
 include/linux/kprobes.h |    4
 kernel/Makefile         |    1
 kernel/djprobe.c        |  253 ++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/kprobes.c        |    8 +
 5 files changed, 345 insertions(+), 1 deletion(-)
diff -Narup linux-2.6.14-rc5-mm1.djp.1/include/linux/djprobe.h linux-2.6.14-rc5-mm1.djp.2/include/linux/djprobe.h
--- linux-2.6.14-rc5-mm1.djp.1/include/linux/djprobe.h	1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.2/include/linux/djprobe.h	2005-10-26 15:52:22.000000000 +0900
@@ -0,0 +1,80 @@
+#ifndef _LINUX_DJPROBE_H
+#define _LINUX_DJPROBE_H
+/*
+ *  Kernel Direct Jump Probe (Djprobe)
+ *  include/linux/djprobe.h
+ *
+ * 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
+ * (at your option) 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) Hitachi, Ltd. 2005
+ *
+ * 2005-Aug	Created by Masami HIRAMATSU <hiramatu@sdl.hitachi.co.jp>
+ * 		Initial implementation of Direct jump probe (djprobe)
+ *              to reduce overhead.
+ */
+#include <linux/config.h>
+#include <linux/list.h>
+#include <linux/smp.h>
+#include <linux/kprobes.h>
+#include <asm/djprobe.h>
+
+struct djprobe;
+/* djprobe's instance (internal use)*/
+struct djprobe_instance {
+	struct list_head plist; /* list of djprobes for multiprobe support */
+	struct arch_djprobe_stub stub;
+	struct kprobe kp;
+	struct hlist_node hlist; /* list of djprobe_instances */
+};
+#define DJPI_EMPTY(djpi)  (list_empty(&djpi->plist))
+
+struct djprobe;
+typedef void (*djprobe_handler_t) (struct djprobe *, struct pt_regs *);
+/*
+ * Direct Jump probe interface structure
+ */
+struct djprobe {
+	/* list of djprobes */
+	struct list_head plist;
+
+	/* probing handler (pre-executed) */
+	djprobe_handler_t handler;
+	
+	/* pointer for instance */
+	struct djprobe_instance *inst;
+};
+
+#ifdef CONFIG_DJPROBE
+extern int arch_prepare_djprobe_instance(struct djprobe_instance *djpi,
+					 unsigned long size);
+extern int djprobe_pre_handler(struct kprobe *, struct pt_regs *);
+extern void djprobe_post_handler(struct kprobe *, struct pt_regs *,
+				 unsigned long);
+extern void arch_install_djprobe_instance(struct djprobe_instance *djpi);
+extern void arch_uninstall_djprobe_instance(struct djprobe_instance *djpi);
+struct djprobe_instance *__kprobes get_djprobe_instance(void *addr, int size);
+
+int register_djprobe(struct djprobe *p, void *addr, int size);
+void unregister_djprobe(struct djprobe *p);
+#else /* CONFIG_DJPROBE */
+static inline int register_djprobe(struct djprobe *p)
+{
+	return -ENOSYS;
+}
+static inline void unregister_djprobe(struct djprobe *p)
+{
+}
+#endif				/* CONFIG_DJPROBE */
+#endif				/* _LINUX_DJPROBE_H */
diff -Narup linux-2.6.14-rc5-mm1.djp.1/include/linux/kprobes.h linux-2.6.14-rc5-mm1.djp.2/include/linux/kprobes.h
--- linux-2.6.14-rc5-mm1.djp.1/include/linux/kprobes.h	2005-10-25 13:11:26.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.2/include/linux/kprobes.h	2005-10-25 13:32:59.000000000 +0900
@@ -163,10 +163,14 @@ extern int arch_init_kprobes(void);
 extern void show_registers(struct pt_regs *regs);
 extern kprobe_opcode_t *get_insn_slot(void);
 extern void free_insn_slot(kprobe_opcode_t *slot);
+extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_page_list *pages);
+extern void __free_insn_slot(struct kprobe_insn_page_list *pages,
+			     kprobe_opcode_t * slot);

 /* Get the kprobe at this addr (if any) - called under a rcu_read_lock() */
 struct kprobe *get_kprobe(void *addr);
 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
+int in_kprobes_functions(unsigned long addr);

 /* kprobe_running() will just return the current_kprobe on this CPU */
 static inline struct kprobe *kprobe_running(void)
diff -Narup linux-2.6.14-rc5-mm1.djp.1/kernel/djprobe.c linux-2.6.14-rc5-mm1.djp.2/kernel/djprobe.c
--- linux-2.6.14-rc5-mm1.djp.1/kernel/djprobe.c	1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.2/kernel/djprobe.c	2005-10-27 11:59:10.000000000 +0900
@@ -0,0 +1,253 @@
+/*
+ *  Kernel Direct Jump Probe (Djprobe)
+ *  kernel/djprobes.c
+ *
+ * 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
+ * (at your option) 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) Hitachi, Ltd. 2005
+ *
+ * 2005-Aug	Created by Masami HIRAMATSU <hiramatu@sdl.hitachi.co.jp>
+ * 		Initial implementation of Direct jump probe (djprobe)
+ *              to reduce overhead.
+ */
+#include <linux/djprobe.h>
+#include <linux/hash.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleloader.h>
+#include <asm-generic/sections.h>
+#include <asm/cacheflush.h>
+#include <asm/errno.h>
+
+#include <linux/cpu.h>
+#include <linux/percpu.h>
+#include <asm/semaphore.h>
+
+/*
+ * The djprobe do not refer instances list when probe function called.
+ * This list is operated on registering and unregistering djprobe.
+ */
+#define DJPROBE_BLOCK_BITS 6
+#define DJPROBE_BLOCK_SIZE (1 << DJPROBE_BLOCK_BITS)
+#define DJPROBE_HASH_BITS 8
+#define DJPROBE_TABLE_SIZE (1 << DJPROBE_HASH_BITS)
+#define DJPROBE_TABLE_MASK (DJPROBE_TABLE_SIZE - 1)
+
+/* djprobe instance hash table */
+static struct hlist_head djprobe_inst_table[DJPROBE_TABLE_SIZE];
+
+#define hash_djprobe(key) \
+	(((unsigned long)(key) >> DJPROBE_BLOCK_BITS) & DJPROBE_TABLE_MASK)
+
+static DECLARE_MUTEX(djprobe_mutex);
+static DEFINE_PER_CPU(struct work_struct, djprobe_works);
+static DECLARE_WAIT_QUEUE_HEAD(djprobe_wqh);
+static atomic_t djprobe_count = ATOMIC_INIT(0);
+
+/* Instruction pages for djprobe's stub code */
+static struct kprobe_insn_page_list djprobe_insn_pages = {
+	HLIST_HEAD_INIT, 0
+};
+
+static inline void __free_djprobe_instance(struct djprobe_instance *djpi)
+{
+	hlist_del(&djpi->hlist);
+	if (djpi->kp.addr) {
+		unregister_kprobe(&(djpi->kp));
+	}
+	if (djpi->stub.insn)
+		__free_insn_slot(&djprobe_insn_pages, djpi->stub.insn);
+	kfree(djpi);
+}
+
+static inline
+    struct djprobe_instance *__create_djprobe_instance(struct djprobe *djp,
+						       void *addr, int size)
+{
+	struct djprobe_instance *djpi;
+	/* allocate a new instance */
+	djpi = kcalloc(1, sizeof(struct djprobe_instance), GFP_ATOMIC);
+	if (djpi == NULL) {
+		goto out;
+	}
+	/* allocate stub */
+	djpi->stub.insn = __get_insn_slot(&djprobe_insn_pages);
+	if (djpi->stub.insn == NULL) {
+		__free_djprobe_instance(djpi);
+		djpi = NULL;
+		goto out;
+	}
+
+	/* attach */
+	djp->inst = djpi;
+	INIT_LIST_HEAD(&djpi->plist);
+	list_add_rcu(&djp->plist, &djpi->plist);
+	djpi->kp.addr = addr;
+	djpi->kp.pre_handler = djprobe_pre_handler;
+	djpi->kp.post_handler = djprobe_post_handler;
+	arch_prepare_djprobe_instance(djpi, size);
+
+	INIT_HLIST_NODE(&djpi->hlist);
+	hlist_add_head(&djpi->hlist, &djprobe_inst_table[hash_djprobe(addr)]);
+      out:
+	return djpi;
+}
+
+static struct djprobe_instance *__kprobes __get_djprobe_instance(void *addr,
+								 int size)
+{
+	struct djprobe_instance *djpi;
+	struct hlist_node *node;
+	unsigned long idx, eidx;
+
+	idx = hash_djprobe(addr - ARCH_STUB_INSN_MAX);
+	eidx = ((hash_djprobe(addr + size) + 1) & DJPROBE_TABLE_MASK);
+	do {
+		hlist_for_each_entry(djpi, node, &djprobe_inst_table[idx],
+				     hlist) {
+			if (((long)addr <
+			     (long)djpi->kp.addr + DJPI_ARCH_SIZE(djpi))
+			    && ((long)djpi->kp.addr < (long)addr + size)) {
+				return djpi;
+			}
+		}
+		idx = ((idx + 1) & DJPROBE_TABLE_MASK);
+	}while (idx != eidx);
+
+	return NULL;
+}
+
+struct djprobe_instance *__kprobes get_djprobe_instance(void *addr, int size)
+{
+	struct djprobe_instance *djpi;
+	down(&djprobe_mutex);
+	djpi = __get_djprobe_instance(addr, size);
+	up(&djprobe_mutex);
+	return djpi;
+}
+
+/* This work function invoked while djprobe_mutex is locked. */
+static void __kprobes __work_check_safety(void *data)
+{
+	if (atomic_dec_and_test(&djprobe_count)) {
+		wake_up_all(&djprobe_wqh);
+	}
+}
+
+static void __kprobes __check_safety(void)
+{
+	int cpu;
+	struct work_struct *wk;
+	lock_cpu_hotplug();
+	atomic_set(&djprobe_count, num_online_cpus() - 1);
+	for_each_online_cpu(cpu) {
+		if (cpu == smp_processor_id())
+			continue;
+		wk = &per_cpu(djprobe_works, cpu);
+		INIT_WORK(wk, __work_check_safety, NULL);
+		schedule_delayed_work_on(cpu, wk, 0);
+	}
+	wait_event(djprobe_wqh, (atomic_read(&djprobe_count) == 0));
+	unlock_cpu_hotplug();
+}
+
+int __kprobes register_djprobe(struct djprobe *djp, void *addr, int size)
+{
+	struct djprobe_instance *djpi;
+	struct kprobe *kp;
+	int ret = 0, i;
+
+	BUG_ON(in_interrupt());
+
+	if (size > ARCH_STUB_INSN_MAX || size < ARCH_STUB_INSN_MIN)
+		return -EINVAL;
+
+	if ((ret = in_kprobes_functions((unsigned long)addr)) != 0)
+		return ret;
+
+	down(&djprobe_mutex);
+	INIT_LIST_HEAD(&djp->plist);
+	/* check confliction with other djprobes */
+	djpi = __get_djprobe_instance(addr, size);
+	if (djpi) {
+		if (djpi->kp.addr == addr) {
+			djp->inst = djpi;	/* add to another instance */
+			list_add_rcu(&djp->plist, &djpi->plist);
+		} else {
+			ret = -EEXIST;	/* other djprobes were inserted */
+		}
+		goto out;
+	}
+	djpi = __create_djprobe_instance(djp, addr, size);
+	if (djpi == NULL) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* check confliction with kprobes */
+	for (i = 0; i < size; i++) {
+		kp = get_kprobe((void *)((long)addr + i));
+		if (kp != NULL) {
+			ret = -EEXIST;	/* a kprobes were inserted */
+			goto fail;
+		}
+	}
+	ret = register_kprobe(&djpi->kp);
+	if (ret < 0) {
+       fail:
+		djpi->kp.addr = NULL;
+		djp->inst = NULL;
+		list_del_rcu(&djp->plist);
+		__free_djprobe_instance(djpi);
+	} else {
+		__check_safety();
+		arch_install_djprobe_instance(djpi);
+	}
+       out:
+	up(&djprobe_mutex);
+	return ret;
+}
+
+void __kprobes unregister_djprobe(struct djprobe *djp)
+{
+	struct djprobe_instance *djpi;
+
+	BUG_ON(in_interrupt());
+
+	down(&djprobe_mutex);
+	djpi = djp->inst;
+	if (djp->plist.next == djp->plist.prev) {
+		arch_uninstall_djprobe_instance(djpi);	/* this requires irq enabled */
+		list_del_rcu(&djp->plist);
+		djp->inst = NULL;
+		__check_safety();
+		__free_djprobe_instance(djpi);
+	} else {
+		list_del_rcu(&djp->plist);
+		djp->inst = NULL;
+	}
+	up(&djprobe_mutex);
+}
+
+static int __init init_djprobe(void)
+{
+	djprobe_insn_pages.insn_size = ARCH_STUB_SIZE;
+	return 0;
+}
+
+__initcall(init_djprobe);
+
+EXPORT_SYMBOL_GPL(register_djprobe);
+EXPORT_SYMBOL_GPL(unregister_djprobe);
diff -Narup linux-2.6.14-rc5-mm1.djp.1/kernel/kprobes.c linux-2.6.14-rc5-mm1.djp.2/kernel/kprobes.c
--- linux-2.6.14-rc5-mm1.djp.1/kernel/kprobes.c	2005-10-25 13:13:58.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.2/kernel/kprobes.c	2005-10-26 15:53:05.000000000 +0900
@@ -37,6 +37,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/moduleloader.h>
+#include <linux/djprobe.h>
 #include <asm-generic/sections.h>
 #include <asm/cacheflush.h>
 #include <asm/errno.h>
@@ -467,7 +468,7 @@ static inline void cleanup_aggr_kprobe(s
 		spin_unlock_irqrestore(&kprobe_lock, flags);
 }

-static int __kprobes in_kprobes_functions(unsigned long addr)
+int __kprobes in_kprobes_functions(unsigned long addr)
 {
 	if (addr >= (unsigned long)__kprobes_text_start
 		&& addr < (unsigned long)__kprobes_text_end)
@@ -483,6 +484,11 @@ int __kprobes register_kprobe(struct kpr

 	if ((ret = in_kprobes_functions((unsigned long) p->addr)) != 0)
 		return ret;
+#ifdef CONFIG_DJPROBE
+	if (p->pre_handler != djprobe_pre_handler &&
+	    get_djprobe_instance(p->addr, 1) != NULL)
+		return -EEXIST;
+#endif /* CONFIG_DJPROBE */
 	if ((ret = arch_prepare_kprobe(p)) != 0)
 		goto rm_kprobe;

diff -Narup linux-2.6.14-rc5-mm1.djp.1/kernel/Makefile linux-2.6.14-rc5-mm1.djp.2/kernel/Makefile
--- linux-2.6.14-rc5-mm1.djp.1/kernel/Makefile	2005-10-25 11:29:02.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.2/kernel/Makefile	2005-10-25 13:22:27.000000000 +0900
@@ -27,6 +27,7 @@ obj-$(CONFIG_STOP_MACHINE) += stop_machi
 obj-$(CONFIG_AUDIT) += audit.o
 obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
 obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_DJPROBE) += djprobe.o
 obj-$(CONFIG_SYSFS) += ksysfs.o
 obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/

[Patch 3/4][Djprobe] Djprobe update for linux-2.6.14-rc5-mm1

[Masami Hiramatsu]

Hi,

This patch is an i386 architecture dependent code
of djprobe.
The djprobe codes are separated from kprobe.{c,h}

-- 
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: hiramatu@sdl.hitachi.co.jp

 arch/i386/Kconfig               |    8 +
 arch/i386/kernel/Makefile       |    1
 arch/i386/kernel/djprobe.c      |  170 ++++++++++++++++++++++++++++++++++++++++
 arch/i386/kernel/stub_djprobe.S |   77 ++++++++++++++++++
 include/asm-i386/djprobe.h      |   56 +++++++++++++
 5 files changed, 312 insertions(+)
diff -Narup linux-2.6.14-rc5-mm1.djp.2/arch/i386/Kconfig linux-2.6.14-rc5-mm1.djp.3/arch/i386/Kconfig
--- linux-2.6.14-rc5-mm1.djp.2/arch/i386/Kconfig	2005-10-25 11:28:49.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/arch/i386/Kconfig	2005-10-27 11:26:55.000000000 +0900
@@ -1317,6 +1317,14 @@ config KPROBES
 	  a probepoint and specifies the callback.  Kprobes is useful
 	  for kernel debugging, non-intrusive instrumentation and testing.
 	  If in doubt, say "N".
+
+config DJPROBE
+        bool "Direct Jump probe"
+	depends on KPROBES && !PREEMPT
+	help
+	 Djprobe allows you to dynamically hook at any kernel function
+	 entry points and collect the debugging or performance analysis
+	 information non-disruptively.
 endmenu

 source "arch/i386/Kconfig.debug"
diff -Narup linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/djprobe.c linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/djprobe.c
--- linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/djprobe.c	1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/djprobe.c	2005-10-26 16:14:54.000000000 +0900
@@ -0,0 +1,170 @@
+/*
+ *  Kernel Direct Jump Probe (Djprobes)
+ *  arch/i386/kernel/djprobe.c
+ *
+ * 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
+ * (at your option) 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) Hitachi, Ltd. 2005
+ *
+ * 2005-Oct	Created by Masami HIRAMATSU <hiramatu@sdl.hitachi.co.jp>
+ * 		Initial implementation of Direct jump probe (djprobe)
+ *              to reduce overhead.
+ */
+
+#include <linux/config.h>
+#include <linux/djprobe.h>
+#include <linux/ptrace.h>
+#include <linux/spinlock.h>
+#include <linux/preempt.h>
+#include <asm/cacheflush.h>
+#include <asm/kdebug.h>
+#include <asm/desc.h>
+#include <asm/processor.h>
+
+
+/*
+ * When kernel full preemption is enabled, we can't ensure that no threads
+ * are executing the modified code. It may be stored in the stack of the
+ * threads. In this case, the djprobe interfaces are emulated by using
+ * kprobe.
+ * When kernel full preemption is disabled, threads are scheduled
+ * from only limited addresses. So it is easy to check whether the
+ * preemption can occur in the modified code.
+ */
+
+/*
+ * On pentium series, Unsynchronized cross-modifying code
+ * operations can cause unexpected instruction execution results.
+ * So after code modified, we should synchronize it on each processor.
+ */
+static void __local_serialize_cpu(void * info)
+{
+	serialize_cpu();
+}
+
+static inline void smp_serialize_cpus(void)
+{
+	on_each_cpu(__local_serialize_cpu, NULL, 1,1);
+}
+
+/* jmp code manipulators */
+struct __arch_jmp_op {
+	char op;
+	long raddr;
+} __attribute__((packed));
+/* insert jmp code */
+static inline void __set_jmp_op(void *from, void *to, int sync)
+{
+	struct __arch_jmp_op *jop;
+	jop = (struct __arch_jmp_op *)from;
+	jop->raddr=(long)(to) - ((long)(from) + 5);
+	mb();
+	if (sync) smp_serialize_cpus();
+	jop->op = RELATIVEJUMP_INSTRUCTION;
+}
+/* switch back to the kprobe */
+static inline void __set_breakpoint_op(void *dest, void *orig)
+{
+	struct __arch_jmp_op *jop = (struct __arch_jmp_op *)dest,
+		*jop2 = (struct __arch_jmp_op *)orig;
+
+	jop->op = BREAKPOINT_INSTRUCTION;
+	jop->raddr = jop2->raddr;
+	mb();
+	smp_serialize_cpus();
+}
+
+/* djprobe call back function: called from stub code */
+static void asmlinkage djprobe_callback(struct djprobe_instance * djpi,
+					struct pt_regs *regs)
+{
+	struct djprobe *djp;
+	list_for_each_entry_rcu(djp, &djpi->plist, plist) {
+		if (djp->handler)
+			djp->handler(djp, regs);
+	}
+}
+
+/*
+ * Copy post processing instructions
+ * Target instructions MUST be relocatable.
+ */
+int __kprobes arch_prepare_djprobe_instance(struct djprobe_instance *djpi,
+				  unsigned long size)
+{
+	kprobe_opcode_t *stub;
+	stub = djpi->stub.insn;
+	djpi->stub.size = size;
+
+	/* copy arch-dep-instance from template */
+	memcpy((void*)stub, (void*)&arch_tmpl_stub_entry, ARCH_STUB_SIZE);
+
+	/* set probe information */
+	*((long*)(stub + ARCH_STUB_VAL_IDX)) = (long)djpi;
+	/* set probe function */
+	*((long*)(stub + ARCH_STUB_CALL_IDX)) = (long)djprobe_callback;
+
+	/* copy instructions into the middle of djporbe instance */
+	memcpy((void*)(stub + ARCH_STUB_INST_IDX),
+	       (void*)djpi->kp.addr, size);
+
+	/* set returning jmp instruction at the tail of djporbe instance*/
+	__set_jmp_op(stub + ARCH_STUB_INST_IDX + size,
+		     (void*)((long)djpi->kp.addr + size), 0);
+
+	return 0;
+}
+
+/* Insert "jmp" instruction into the probing point. */
+void __kprobes arch_install_djprobe_instance(struct djprobe_instance *djpi)
+{
+	__set_jmp_op((void*)djpi->kp.addr, (void*)djpi->stub.insn, 1);
+}
+
+/* Write back original instructions & kprobe */
+void __kprobes arch_uninstall_djprobe_instance(struct djprobe_instance *djpi)
+{
+	kprobe_opcode_t *stub;
+	stub = &djpi->stub.insn[ARCH_STUB_INST_IDX];
+	__set_breakpoint_op((void*)djpi->kp.addr, (void*)stub);
+}
+
+static DEFINE_SPINLOCK(djprobe_handler_lock);
+
+/* djprobe handler : switch to a bypass code */
+int __kprobes djprobe_pre_handler(struct kprobe * kp, struct pt_regs * regs)
+{
+	struct djprobe_instance *djpi =
+		container_of(kp,struct djprobe_instance, kp);
+	kprobe_opcode_t *stub = djpi->stub.insn;
+
+	spin_lock(&djprobe_handler_lock);
+	if (DJPI_EMPTY(djpi)) {
+		kp->ainsn.insn[0] = kp->opcode;
+		return 0;
+	} else {
+		regs->eip = (unsigned long)stub;
+		regs->eflags |= TF_MASK;
+		regs->eflags &= ~IF_MASK;
+		kp->ainsn.insn[0] = RETURN_INSTRUCTION;
+		return 1; /* already prepared */
+	}
+}
+
+void __kprobes djprobe_post_handler(struct kprobe * kp, struct pt_regs * regs,
+				    unsigned long flags)
+{
+	spin_unlock(&djprobe_handler_lock);
+}
diff -Narup linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/Makefile linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/Makefile
--- linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/Makefile	2005-10-25 11:28:49.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/Makefile	2005-10-25 14:39:12.000000000 +0900
@@ -29,6 +29,7 @@ obj-$(CONFIG_KEXEC)		+= machine_kexec.o
 obj-$(CONFIG_X86_NUMAQ)		+= numaq.o
 obj-$(CONFIG_X86_SUMMIT_NUMA)	+= summit.o
 obj-$(CONFIG_KPROBES)		+= kprobes.o
+obj-$(CONFIG_DJPROBE)		+= stub_djprobe.o djprobe.o
 obj-$(CONFIG_MODULES)		+= module.o
 obj-y				+= sysenter.o vsyscall.o
 obj-$(CONFIG_ACPI_SRAT) 	+= srat.o
diff -Narup linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/stub_djprobe.S linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/stub_djprobe.S
--- linux-2.6.14-rc5-mm1.djp.2/arch/i386/kernel/stub_djprobe.S	1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/arch/i386/kernel/stub_djprobe.S	2005-10-25 14:39:12.000000000 +0900
@@ -0,0 +1,77 @@
+/*
+ *  linux/arch/i386/stub_djprobe.S
+ *
+ *  Copyright (C) HITACHI,LTD. 2005
+ *  Created by Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
+ */
+
+#include <linux/config.h>
+
+# jmp into this function from other functions.
+.global arch_tmpl_stub_entry
+arch_tmpl_stub_entry:
+	nop
+	subl $8, %esp	#skip segment registers.
+	pushf
+	subl $20, %esp	#skip segment registers.
+	pushl %eax
+	pushl %ebp
+	pushl %edi
+	pushl %esi
+	pushl %edx
+	pushl %ecx
+	pushl %ebx
+
+	movl %esp, %eax
+	pushl %eax
+	addl $60, %eax
+	movl %eax, 56(%esp)
+.global arch_tmpl_stub_val
+arch_tmpl_stub_val:
+	movl $0xffffffff, %eax
+	pushl %eax
+.global arch_tmpl_stub_call
+arch_tmpl_stub_call:
+	movl $0xffffffff, %eax
+	call *%eax
+	addl $8, %esp
+
+	popl %ebx
+	popl %ecx
+	popl %edx
+	popl %esi
+	popl %edi
+	popl %ebp
+	popl %eax
+	addl $20, %esp
+	popf
+	addl $8, %esp
+.global arch_tmpl_stub_inst
+arch_tmpl_stub_inst:
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+.global arch_tmpl_stub_end
+arch_tmpl_stub_end:
diff -Narup linux-2.6.14-rc5-mm1.djp.2/include/asm-i386/djprobe.h linux-2.6.14-rc5-mm1.djp.3/include/asm-i386/djprobe.h
--- linux-2.6.14-rc5-mm1.djp.2/include/asm-i386/djprobe.h	1970-01-01 09:00:00.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.3/include/asm-i386/djprobe.h	2005-10-25 14:39:12.000000000 +0900
@@ -0,0 +1,56 @@
+#ifndef _ASM_DJPROBE_H
+#define _ASM_DJPROBE_H
+/*
+ *  Kernel Direct Jump Probe (Djprobe)
+ *  include/asm-i386/djprobe.h
+ *
+ * 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
+ * (at your option) 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) Hitachi, Ltd. 2005
+ *
+ * 2005-Aug	Created by Masami HIRAMATSU <hiramatu@sdl.hitachi.co.jp>
+ * 		Initial implementation of Direct jump probe (djprobe)
+ *              to reduce overhead.
+ */
+
+#define RELATIVEJUMP_INSTRUCTION 0xe9
+#define RETURN_INSTRUCTION 0xc3
+
+#ifndef CONFIG_PREEMPT
+#define ARCH_SUPPORTS_DJPROBES
+#endif				/* CONFIG_PREEMPT */
+
+/* stub template code */
+extern kprobe_opcode_t arch_tmpl_stub_entry;
+extern kprobe_opcode_t arch_tmpl_stub_val;
+extern kprobe_opcode_t arch_tmpl_stub_call;
+extern kprobe_opcode_t arch_tmpl_stub_inst;
+extern kprobe_opcode_t arch_tmpl_stub_end;
+
+#define ARCH_STUB_VAL_IDX ((long)&arch_tmpl_stub_val - (long)&arch_tmpl_stub_entry + 1)
+#define ARCH_STUB_CALL_IDX ((long)&arch_tmpl_stub_call - (long)&arch_tmpl_stub_entry + 1)
+#define ARCH_STUB_INST_IDX ((long)&arch_tmpl_stub_inst - (long)&arch_tmpl_stub_entry)
+#define ARCH_STUB_SIZE ((long)&arch_tmpl_stub_end - (long)&arch_tmpl_stub_entry)
+
+#define ARCH_STUB_INSN_MAX 20
+#define ARCH_STUB_INSN_MIN 5
+
+struct arch_djprobe_stub {
+	kprobe_opcode_t *insn;
+	int size;
+};
+#define DJPI_ARCH_SIZE(djpi) (djpi->stub.size)
+
+#endif				/* _ASM_DJPROBE_H */

[Patch 4/4][Djprobe][testing] Djprobe update for linux-2.6.14-rc5-mm1

[Masami Hiramatsu]

Hi,

This patch provides bulk registration/unregistration interfaces
to djprobe.

-- 
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: hiramatu@sdl.hitachi.co.jp

 include/linux/djprobe.h |   20 ++++++++++++
 kernel/djprobe.c        |   80 +++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 86 insertions(+), 14 deletions(-)
diff -Narup linux-2.6.14-rc5-mm1.djp.3/include/linux/djprobe.h linux-2.6.14-rc5-mm1.djp.4/include/linux/djprobe.h
--- linux-2.6.14-rc5-mm1.djp.3/include/linux/djprobe.h	2005-10-26 15:52:22.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.4/include/linux/djprobe.h	2005-10-27 11:16:31.000000000 +0900
@@ -56,6 +56,12 @@ struct djprobe {
 	struct djprobe_instance *inst;
 };

+struct djprobe_param {
+	struct djprobe *djp;
+	void *addr;
+	int size;
+};
+
 #ifdef CONFIG_DJPROBE
 extern int arch_prepare_djprobe_instance(struct djprobe_instance *djpi,
 					 unsigned long size);
@@ -67,14 +73,28 @@ extern void arch_uninstall_djprobe_insta
 struct djprobe_instance *__kprobes get_djprobe_instance(void *addr, int size);

 int register_djprobe(struct djprobe *p, void *addr, int size);
+void register_bulk_djprobes(int nr_probes, struct djprobe_param params[]);
 void unregister_djprobe(struct djprobe *p);
+void unregister_bulk_djprobes(int nr_probes, struct djprobe_param params[]);
 #else /* CONFIG_DJPROBE */
 static inline int register_djprobe(struct djprobe *p)
 {
 	return -ENOSYS;
 }
+static inline void register_bulk_djprobes(int nr_probes,
+					  struct djprobe_param params[])
+{
+	int i;
+	for (i=0;i<nr_probes;i++)
+		params[i].djp->inst = NULL;
+}
+
 static inline void unregister_djprobe(struct djprobe *p)
 {
 }
+static inline void unregister_bulk_djprobes(int nr_probes,
+					    struct djprobe_param params[])
+{
+}
 #endif				/* CONFIG_DJPROBE */
 #endif				/* _LINUX_DJPROBE_H */
diff -Narup linux-2.6.14-rc5-mm1.djp.3/kernel/djprobe.c linux-2.6.14-rc5-mm1.djp.4/kernel/djprobe.c
--- linux-2.6.14-rc5-mm1.djp.3/kernel/djprobe.c	2005-10-27 11:59:10.000000000 +0900
+++ linux-2.6.14-rc5-mm1.djp.4/kernel/djprobe.c	2005-10-27 12:01:54.000000000 +0900
@@ -163,7 +163,8 @@ static void __kprobes __check_safety(voi
 	unlock_cpu_hotplug();
 }

-int __kprobes register_djprobe(struct djprobe *djp, void *addr, int size)
+static int __kprobes __register_djprobe(struct djprobe *djp, void *addr,
+					int size)
 {
 	struct djprobe_instance *djpi;
 	struct kprobe *kp;
@@ -177,7 +178,6 @@ int __kprobes register_djprobe(struct dj
 	if ((ret = in_kprobes_functions((unsigned long)addr)) != 0)
 		return ret;

-	down(&djprobe_mutex);
 	INIT_LIST_HEAD(&djp->plist);
 	/* check confliction with other djprobes */
 	djpi = __get_djprobe_instance(addr, size);
@@ -211,32 +211,82 @@ int __kprobes register_djprobe(struct dj
 		djp->inst = NULL;
 		list_del_rcu(&djp->plist);
 		__free_djprobe_instance(djpi);
-	} else {
-		__check_safety();
-		arch_install_djprobe_instance(djpi);
 	}
        out:
+	return ret;
+}
+
+int __kprobes register_djprobe(struct djprobe *djp, void *addr, int size)
+{
+	int ret;
+	down(&djprobe_mutex);
+	ret = __register_djprobe(djp, addr, size);
+	if (ret == 0) {
+		__check_safety();
+		arch_install_djprobe_instance(djp->inst);
+	}
 	up(&djprobe_mutex);
 	return ret;
 }

-void __kprobes unregister_djprobe(struct djprobe *djp)
+void __kprobes register_bulk_djprobes(int nr_probes,
+				      struct djprobe_param params[])
 {
-	struct djprobe_instance *djpi;
+	int i;
+	down(&djprobe_mutex);
+	for (i = 0; i < nr_probes; i++) {
+		params[i].djp->inst = NULL;
+		__register_djprobe(params[i].djp, params[i].addr,
+				   params[i].size);
+ 	}
+	__check_safety();
+	for (i = 0; i < nr_probes; i++) {
+		if (params[i].djp->inst)
+			arch_install_djprobe_instance(params[i].djp->inst);
+	}
+	up(&djprobe_mutex);
+}

+static void __kprobes __unregister_djprobe(struct djprobe *djp)
+{
 	BUG_ON(in_interrupt());

+	if (djp->plist.next == djp->plist.prev) {
+		/* this requires irq enabled */
+		arch_uninstall_djprobe_instance(djp->inst);
+	}
+	list_del_rcu(&djp->plist);
+	djp->inst = NULL;
+}
+
+void __kprobes unregister_djprobe(struct djprobe *djp)
+{
+	struct djprobe_instance *djpi;
 	down(&djprobe_mutex);
 	djpi = djp->inst;
-	if (djp->plist.next == djp->plist.prev) {
-		arch_uninstall_djprobe_instance(djpi);	/* this requires irq enabled */
-		list_del_rcu(&djp->plist);
-		djp->inst = NULL;
+	__unregister_djprobe(djp);
+	if (DJPI_EMPTY(djpi)) {
 		__check_safety();
 		__free_djprobe_instance(djpi);
-	} else {
-		list_del_rcu(&djp->plist);
-		djp->inst = NULL;
+	}
+	up(&djprobe_mutex);
+}
+
+void __kprobes unregister_bulk_djprobes(int nr_probes,
+					struct djprobe_param params[])
+{
+	struct djprobe_instance *djpi;
+	int i;
+	down(&djprobe_mutex);
+	for (i = 0; i < nr_probes; i++) {
+		__unregister_djprobe(params[i].djp);
+	}
+	__check_safety();
+	for (i = 0; i < nr_probes; i++) {
+		djpi = __get_djprobe_instance(params[i].addr, 1);
+		if (djpi && DJPI_EMPTY(djpi)) {
+			__free_djprobe_instance(djpi);
+		}
 	}
 	up(&djprobe_mutex);
 }
@@ -250,4 +300,6 @@ static int __init init_djprobe(void)
 __initcall(init_djprobe);

 EXPORT_SYMBOL_GPL(register_djprobe);
+EXPORT_SYMBOL_GPL(register_bulk_djprobes);
 EXPORT_SYMBOL_GPL(unregister_djprobe);
+EXPORT_SYMBOL_GPL(unregister_bulk_djprobes);