---

yaml --- r: 30229 b: refs/heads/master c: e6f47f9 h: refs/heads/master i: 30227: 2be938f v: v3
git-mirror · Jun 26, 2006 · 8c52d5a · 8c52d5a
1 parent 2378a57
commit 8c52d5a
Show file tree

Hide file tree

Showing 7 changed files with 30 additions and 8 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3d5631e0631a11633c649bc995a6537ec21b67b4
+refs/heads/master: e6f47f978bcd5413fff610613b18e9e0eab9bc1b
diff --git a/trunk/include/asm-i386/kprobes.h b/trunk/include/asm-i386/kprobes.h
@@ -44,6 +44,7 @@ typedef u8 kprobe_opcode_t;
 
 #define JPROBE_ENTRY(pentry)	(kprobe_opcode_t *)pentry
 #define ARCH_SUPPORTS_KRETPROBES
+#define  ARCH_INACTIVE_KPROBE_COUNT 0
 
 void arch_remove_kprobe(struct kprobe *p);
 void kretprobe_trampoline(void);

diff --git a/trunk/include/asm-ia64/kprobes.h b/trunk/include/asm-ia64/kprobes.h
@@ -82,6 +82,7 @@ struct kprobe_ctlblk {
 #define JPROBE_ENTRY(pentry)	(kprobe_opcode_t *)pentry
 
 #define ARCH_SUPPORTS_KRETPROBES
+#define  ARCH_INACTIVE_KPROBE_COUNT 1
 
 #define SLOT0_OPCODE_SHIFT	(37)
 #define SLOT1_p1_OPCODE_SHIFT	(37 - (64-46))

diff --git a/trunk/include/asm-powerpc/kprobes.h b/trunk/include/asm-powerpc/kprobes.h
@@ -50,6 +50,8 @@ typedef unsigned int kprobe_opcode_t;
 			IS_TWI(instr) || IS_TDI(instr))
 
 #define ARCH_SUPPORTS_KRETPROBES
+#define  ARCH_INACTIVE_KPROBE_COUNT 1
+
 void kretprobe_trampoline(void);
 extern void arch_remove_kprobe(struct kprobe *p);
 

diff --git a/trunk/include/asm-sparc64/kprobes.h b/trunk/include/asm-sparc64/kprobes.h
@@ -12,6 +12,7 @@ typedef u32 kprobe_opcode_t;
 
 #define JPROBE_ENTRY(pentry)	(kprobe_opcode_t *)pentry
 #define arch_remove_kprobe(p)	do {} while (0)
+#define  ARCH_INACTIVE_KPROBE_COUNT 0
 
 /* Architecture specific copy of original instruction*/
 struct arch_specific_insn {

diff --git a/trunk/include/asm-x86_64/kprobes.h b/trunk/include/asm-x86_64/kprobes.h
@@ -43,6 +43,7 @@ typedef u8 kprobe_opcode_t;
 
 #define JPROBE_ENTRY(pentry)	(kprobe_opcode_t *)pentry
 #define ARCH_SUPPORTS_KRETPROBES
+#define  ARCH_INACTIVE_KPROBE_COUNT 1
 
 void kretprobe_trampoline(void);
 extern void arch_remove_kprobe(struct kprobe *p);

diff --git a/trunk/kernel/kprobes.c b/trunk/kernel/kprobes.c
@@ -47,11 +47,17 @@
 
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
+static atomic_t kprobe_count;
 
 DEFINE_MUTEX(kprobe_mutex);		/* Protects kprobe_table */
 DEFINE_SPINLOCK(kretprobe_lock);	/* Protects kretprobe_inst_table */
 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
 
+static struct notifier_block kprobe_page_fault_nb = {
+	.notifier_call = kprobe_exceptions_notify,
+	.priority = 0x7fffffff /* we need to notified first */
+};
+
 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
 /*
  * kprobe->ainsn.insn points to the copy of the instruction to be
@@ -465,6 +471,8 @@ static int __kprobes __register_kprobe(struct kprobe *p,
 	old_p = get_kprobe(p->addr);
 	if (old_p) {
 		ret = register_aggr_kprobe(old_p, p);
+		if (!ret)
+			atomic_inc(&kprobe_count);
 		goto out;
 	}
 
@@ -475,6 +483,10 @@ static int __kprobes __register_kprobe(struct kprobe *p,
 	hlist_add_head_rcu(&p->hlist,
 		       &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
 
+	if (atomic_add_return(1, &kprobe_count) == \
+				(ARCH_INACTIVE_KPROBE_COUNT + 1))
+		register_page_fault_notifier(&kprobe_page_fault_nb);
+
   	arch_arm_kprobe(p);
 
 out:
@@ -553,17 +565,23 @@ void __kprobes unregister_kprobe(struct kprobe *p)
 		}
 		mutex_unlock(&kprobe_mutex);
 	}
+
+	/* Call unregister_page_fault_notifier()
+	 * if no probes are active
+	 */
+	mutex_lock(&kprobe_mutex);
+	if (atomic_add_return(-1, &kprobe_count) == \
+				ARCH_INACTIVE_KPROBE_COUNT)
+		unregister_page_fault_notifier(&kprobe_page_fault_nb);
+	mutex_unlock(&kprobe_mutex);
+	return;
 }
 
 static struct notifier_block kprobe_exceptions_nb = {
 	.notifier_call = kprobe_exceptions_notify,
 	.priority = 0x7fffffff /* we need to be notified first */
 };
 
-static struct notifier_block kprobe_page_fault_nb = {
-	.notifier_call = kprobe_exceptions_notify,
-	.priority = 0x7fffffff /* we need to notified first */
-};
 
 int __kprobes register_jprobe(struct jprobe *jp)
 {
@@ -673,14 +691,12 @@ static int __init init_kprobes(void)
 		INIT_HLIST_HEAD(&kprobe_table[i]);
 		INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
 	}
+	atomic_set(&kprobe_count, 0);
 
 	err = arch_init_kprobes();
 	if (!err)
 		err = register_die_notifier(&kprobe_exceptions_nb);
 
-	if (!err)
-		err = register_page_fault_notifier(&kprobe_page_fault_nb);
-
 	return err;
 }