2 files changed, 22 insertions, 75 deletions

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index d304d4579856..b7a194c4362a 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -104,33 +104,12 @@ struct jprobe {
 };
 
 #ifdef ARCH_SUPPORTS_KRETPROBES
-extern int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs);
-extern void trampoline_post_handler(struct kprobe *p, struct pt_regs *regs,
-                                                        unsigned long flags);
-extern struct task_struct *arch_get_kprobe_task(void *ptr);
 extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs);
-extern void arch_kprobe_flush_task(struct task_struct *tk);
 #else /* ARCH_SUPPORTS_KRETPROBES */
-static inline void kretprobe_trampoline(void)
-{
-}
-static inline int trampoline_probe_handler(struct kprobe *p,
-                                                struct pt_regs *regs)
-{
-        return 0;
-}
-static inline void trampoline_post_handler(struct kprobe *p,
-                                struct pt_regs *regs, unsigned long flags)
-{
-}
 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
                                         struct pt_regs *regs)
 {
 }
-static inline void arch_kprobe_flush_task(struct task_struct *tk)
-{
-}
-#define arch_get_kprobe_task(ptr) ((struct task_struct *)NULL)
 #endif /* ARCH_SUPPORTS_KRETPROBES */
 /*
  * Function-return probe -
@@ -155,8 +134,8 @@ struct kretprobe_instance {
         struct hlist_node uflist; /* either on free list or used list */
         struct hlist_node hlist;
         struct kretprobe *rp;
-        void *ret_addr;
-        void *stack_addr;
+        kprobe_opcode_t *ret_addr;
+        struct task_struct *task;
 };
 
 #ifdef CONFIG_KPROBES
@@ -176,6 +155,7 @@ extern void arch_copy_kprobe(struct kprobe *p);
 extern void arch_arm_kprobe(struct kprobe *p);
 extern void arch_disarm_kprobe(struct kprobe *p);
 extern void arch_remove_kprobe(struct kprobe *p);
+extern int arch_init(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);
@@ -196,8 +176,6 @@ int register_kretprobe(struct kretprobe *rp);
 void unregister_kretprobe(struct kretprobe *rp);
 
 struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp);
-struct kretprobe_instance *get_rp_inst(void *sara);
-struct kretprobe_instance *get_rp_inst_tsk(struct task_struct *tk);
 void add_rp_inst(struct kretprobe_instance *ri);
 void kprobe_flush_task(struct task_struct *tk);
 void recycle_rp_inst(struct kretprobe_instance *ri);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 65242529a75f..90c0e82b650c 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -240,12 +240,6 @@ static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
         return 0;
 }
 
-struct kprobe trampoline_p = {
-                .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
-                .pre_handler = trampoline_probe_handler,
-                .post_handler = trampoline_post_handler
-};
-
 struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp)
 {
         struct hlist_node *node;
@@ -264,35 +258,18 @@ static struct kretprobe_instance *get_used_rp_inst(struct kretprobe *rp)
         return NULL;
 }
 
-struct kretprobe_instance *get_rp_inst(void *sara)
-{
-        struct hlist_head *head;
-        struct hlist_node *node;
-        struct task_struct *tsk;
-        struct kretprobe_instance *ri;
-
-        tsk = arch_get_kprobe_task(sara);
-        head = &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)];
-        hlist_for_each_entry(ri, node, head, hlist) {
-                if (ri->stack_addr == sara)
-                        return ri;
-        }
-        return NULL;
-}
-
 void add_rp_inst(struct kretprobe_instance *ri)
 {
-        struct task_struct *tsk;
         /*
          * Remove rp inst off the free list -
          * Add it back when probed function returns
          */
         hlist_del(&ri->uflist);
-        tsk = arch_get_kprobe_task(ri->stack_addr);
+
         /* Add rp inst onto table */
         INIT_HLIST_NODE(&ri->hlist);
         hlist_add_head(&ri->hlist,
-                        &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)]);
+                        &kretprobe_inst_table[hash_ptr(ri->task, KPROBE_HASH_BITS)]);
 
         /* Also add this rp inst to the used list. */
         INIT_HLIST_NODE(&ri->uflist);
@@ -319,34 +296,25 @@ struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk)
         return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)];
 }
 
-struct kretprobe_instance *get_rp_inst_tsk(struct task_struct *tk)
-{
-        struct task_struct *tsk;
-        struct hlist_head *head;
-        struct hlist_node *node;
-        struct kretprobe_instance *ri;
-
-        head = &kretprobe_inst_table[hash_ptr(tk, KPROBE_HASH_BITS)];
-
-        hlist_for_each_entry(ri, node, head, hlist) {
-                tsk = arch_get_kprobe_task(ri->stack_addr);
-                if (tsk == tk)
-                        return ri;
-        }
-        return NULL;
-}
-
 /*
- * This function is called from do_exit or do_execv when task tk's stack is
- * about to be recycled. Recycle any function-return probe instances
- * associated with this task. These represent probed functions that have
- * been called but may never return.
+ * This function is called from exit_thread or flush_thread when task tk's
+ * stack is being recycled so that we can recycle any function-return probe
+ * instances associated with this task. These left over instances represent
+ * probed functions that have been called but will never return.
  */
 void kprobe_flush_task(struct task_struct *tk)
 {
+        struct kretprobe_instance *ri;
+        struct hlist_head *head;
+        struct hlist_node *node, *tmp;
         unsigned long flags = 0;
+
         spin_lock_irqsave(&kprobe_lock, flags);
-        arch_kprobe_flush_task(tk);
+        head = kretprobe_inst_table_head(current);
+        hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+                if (ri->task == tk)
+                        recycle_rp_inst(ri);
+        }
         spin_unlock_irqrestore(&kprobe_lock, flags);
 }
 
@@ -606,9 +574,10 @@ static int __init init_kprobes(void)
                 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
         }
 
-        err = register_die_notifier(&kprobe_exceptions_nb);
-        /* Register the trampoline probe for return probe */
-        register_kprobe(&trampoline_p);
+        err = arch_init();
+        if (!err)
+                err = register_die_notifier(&kprobe_exceptions_nb);
+
         return err;
 }