kprobes: add (un)register_kretprobes for batch registration

Introduce unregister_/register_kretprobes() for kretprobe batch registration.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: David Miller <davem@davemloft.net>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 97 insertions, 20 deletions

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 2ba7df645a84..94c855a236ae 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -245,6 +245,8 @@ unsigned long arch_deref_entry_point(void *);
 
 int register_kretprobe(struct kretprobe *rp);
 void unregister_kretprobe(struct kretprobe *rp);
+int register_kretprobes(struct kretprobe **rps, int num);
+void unregister_kretprobes(struct kretprobe **rps, int num);
 
 void kprobe_flush_task(struct task_struct *tk);
 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
@@ -287,9 +289,16 @@ static inline int register_kretprobe(struct kretprobe *rp)
 {
         return -ENOSYS;
 }
+static inline int register_kretprobes(struct kretprobe **rps, int num)
+{
+        return -ENOSYS;
+}
 static inline void unregister_kretprobe(struct kretprobe *rp)
 {
 }
+static inline void unregister_kretprobes(struct kretprobe **rps, int num)
+{
+}
 static inline void kprobe_flush_task(struct task_struct *tk)
 {
 }
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 76275fc025a5..5e3144ad9b64 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -429,6 +429,21 @@ static inline void free_rp_inst(struct kretprobe *rp)
         }
 }
 
+static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
+{
+        unsigned long flags;
+        struct kretprobe_instance *ri;
+        struct hlist_node *pos, *next;
+        /* No race here */
+        spin_lock_irqsave(&kretprobe_lock, flags);
+        hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) {
+                ri->rp = NULL;
+                hlist_del(&ri->uflist);
+        }
+        spin_unlock_irqrestore(&kretprobe_lock, flags);
+        free_rp_inst(rp);
+}
+
 /*
  * Keep all fields in the kprobe consistent
  */
@@ -798,7 +813,8 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
         return 0;
 }
 
-int __kprobes register_kretprobe(struct kretprobe *rp)
+static int __kprobes __register_kretprobe(struct kretprobe *rp,
+                                          unsigned long called_from)
 {
         int ret = 0;
         struct kretprobe_instance *inst;
@@ -844,43 +860,93 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
 
         rp->nmissed = 0;
         /* Establish function entry probe point */
-        if ((ret = __register_kprobe(&rp->kp,
-                (unsigned long)__builtin_return_address(0))) != 0)
+        ret = __register_kprobe(&rp->kp, called_from);
+        if (ret != 0)
                 free_rp_inst(rp);
         return ret;
 }
 
+static int __register_kretprobes(struct kretprobe **rps, int num,
+        unsigned long called_from)
+{
+        int ret = 0, i;
+
+        if (num <= 0)
+                return -EINVAL;
+        for (i = 0; i < num; i++) {
+                ret = __register_kretprobe(rps[i], called_from);
+                if (ret < 0 && i > 0) {
+                        unregister_kretprobes(rps, i);
+                        break;
+                }
+        }
+        return ret;
+}
+
+int __kprobes register_kretprobe(struct kretprobe *rp)
+{
+        return __register_kretprobes(&rp, 1,
+                        (unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_kretprobe(struct kretprobe *rp)
+{
+        unregister_kretprobes(&rp, 1);
+}
+
+int __kprobes register_kretprobes(struct kretprobe **rps, int num)
+{
+        return __register_kretprobes(rps, num,
+                        (unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
+{
+        int i;
+
+        if (num <= 0)
+                return;
+        mutex_lock(&kprobe_mutex);
+        for (i = 0; i < num; i++)
+                if (__unregister_kprobe_top(&rps[i]->kp) < 0)
+                        rps[i]->kp.addr = NULL;
+        mutex_unlock(&kprobe_mutex);
+
+        synchronize_sched();
+        for (i = 0; i < num; i++) {
+                if (rps[i]->kp.addr) {
+                        __unregister_kprobe_bottom(&rps[i]->kp);
+                        cleanup_rp_inst(rps[i]);
+                }
+        }
+}
+
 #else /* CONFIG_KRETPROBES */
 int __kprobes register_kretprobe(struct kretprobe *rp)
 {
         return -ENOSYS;
 }
 
-static int __kprobes pre_handler_kretprobe(struct kprobe *p,
-                                           struct pt_regs *regs)
+int __kprobes register_kretprobes(struct kretprobe **rps, int num)
 {
-        return 0;
+        return -ENOSYS;
 }
-#endif /* CONFIG_KRETPROBES */
-
 void __kprobes unregister_kretprobe(struct kretprobe *rp)
 {
-        unsigned long flags;
-        struct kretprobe_instance *ri;
-        struct hlist_node *pos, *next;
+}
 
-        unregister_kprobe(&rp->kp);
+void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
+{
+}
 
-        /* No race here */
-        spin_lock_irqsave(&kretprobe_lock, flags);
-        hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) {
-                ri->rp = NULL;
-                hlist_del(&ri->uflist);
-        }
-        spin_unlock_irqrestore(&kretprobe_lock, flags);
-        free_rp_inst(rp);
+static int __kprobes pre_handler_kretprobe(struct kprobe *p,
+                                           struct pt_regs *regs)
+{
+        return 0;
 }
 
+#endif /* CONFIG_KRETPROBES */
+
 static int __init init_kprobes(void)
 {
         int i, err = 0;
@@ -1177,4 +1243,6 @@ EXPORT_SYMBOL_GPL(jprobe_return);
 #ifdef CONFIG_KPROBES
 EXPORT_SYMBOL_GPL(register_kretprobe);
 EXPORT_SYMBOL_GPL(unregister_kretprobe);
+EXPORT_SYMBOL_GPL(register_kretprobes);
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
 #endif