Kprobes: indicate kretprobe support in Kconfig

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / kprobes.c

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 4b8a4493c541873a946e9d62161459fa4f94c35c..e6a61dcbc578e59f115674690e0d3200bba1c32e 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -64,7 +64,6 @@
 
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
-static atomic_t kprobe_count;
 
 /* NOTE: change this value only with kprobe_mutex held */
 static bool kprobe_enabled;
@@ -73,11 +72,6 @@ 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
@@ -556,8 +550,6 @@ 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;
        }
 
@@ -569,13 +561,9 @@ static int __kprobes __register_kprobe(struct kprobe *p,
        hlist_add_head_rcu(&p->hlist,
                       &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
 
-       if (kprobe_enabled) {
-               if (atomic_add_return(1, &kprobe_count) == \
-                               (ARCH_INACTIVE_KPROBE_COUNT + 1))
-                       register_page_fault_notifier(&kprobe_page_fault_nb);
-
+       if (kprobe_enabled)
                arch_arm_kprobe(p);
-       }
+
 out:
        mutex_unlock(&kprobe_mutex);
 
@@ -658,16 +646,6 @@ valid_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 = {
@@ -700,8 +678,7 @@ void __kprobes unregister_jprobe(struct jprobe *jp)
        unregister_kprobe(&jp->kp);
 }
 
-#ifdef ARCH_SUPPORTS_KRETPROBES
-
+#ifdef CONFIG_KRETPROBES
 /*
  * This kprobe pre_handler is registered with every kretprobe. When probe
  * hits it will set up the return probe.
@@ -721,6 +698,12 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
                                 struct kretprobe_instance, uflist);
                ri->rp = rp;
                ri->task = current;
+
+               if (rp->entry_handler && rp->entry_handler(ri, regs)) {
+                       spin_unlock_irqrestore(&kretprobe_lock, flags);
+                       return 0;
+               }
+
                arch_prepare_kretprobe(ri, regs);
 
                /* XXX(hch): why is there no hlist_move_head? */
@@ -738,6 +721,18 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
        int ret = 0;
        struct kretprobe_instance *inst;
        int i;
+       void *addr = rp->kp.addr;
+
+       if (kretprobe_blacklist_size) {
+               if (addr == NULL)
+                       kprobe_lookup_name(rp->kp.symbol_name, addr);
+               addr += rp->kp.offset;
+
+               for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
+                       if (kretprobe_blacklist[i].addr == addr)
+                               return -EINVAL;
+               }
+       }
 
        rp->kp.pre_handler = pre_handler_kretprobe;
        rp->kp.post_handler = NULL;
@@ -755,7 +750,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
        INIT_HLIST_HEAD(&rp->used_instances);
        INIT_HLIST_HEAD(&rp->free_instances);
        for (i = 0; i < rp->maxactive; i++) {
-               inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL);
+               inst = kmalloc(sizeof(struct kretprobe_instance) +
+                              rp->data_size, GFP_KERNEL);
                if (inst == NULL) {
                        free_rp_inst(rp);
                        return -ENOMEM;
@@ -772,8 +768,7 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
        return ret;
 }
 
-#else /* ARCH_SUPPORTS_KRETPROBES */
-
+#else /* CONFIG_KRETPROBES */
 int __kprobes register_kretprobe(struct kretprobe *rp)
 {
        return -ENOSYS;
@@ -784,8 +779,7 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
 {
        return 0;
 }
-
-#endif /* ARCH_SUPPORTS_KRETPROBES */
+#endif /* CONFIG_KRETPROBES */
 
 void __kprobes unregister_kretprobe(struct kretprobe *rp)
 {
@@ -815,7 +809,17 @@ static int __init init_kprobes(void)
                INIT_HLIST_HEAD(&kprobe_table[i]);
                INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
        }
-       atomic_set(&kprobe_count, 0);
+
+       if (kretprobe_blacklist_size) {
+               /* lookup the function address from its name */
+               for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
+                       kprobe_lookup_name(kretprobe_blacklist[i].name,
+                                          kretprobe_blacklist[i].addr);
+                       if (!kretprobe_blacklist[i].addr)
+                               printk("kretprobe: lookup failed: %s\n",
+                                      kretprobe_blacklist[i].name);
+               }
+       }
 
        /* By default, kprobes are enabled */
        kprobe_enabled = true;
@@ -824,6 +828,8 @@ static int __init init_kprobes(void)
        if (!err)
                err = register_die_notifier(&kprobe_exceptions_nb);
 
+       if (!err)
+               init_test_probes();
        return err;
 }
 
@@ -921,13 +927,6 @@ static void __kprobes enable_all_kprobes(void)
        if (kprobe_enabled)
                goto already_enabled;
 
-       /*
-        * Re-register the page fault notifier only if there are any
-        * active probes at the time of enabling kprobes globally
-        */
-       if (atomic_read(&kprobe_count) > ARCH_INACTIVE_KPROBE_COUNT)
-               register_page_fault_notifier(&kprobe_page_fault_nb);
-
        for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
                head = &kprobe_table[i];
                hlist_for_each_entry_rcu(p, node, head, hlist)
@@ -968,10 +967,7 @@ static void __kprobes disable_all_kprobes(void)
        mutex_unlock(&kprobe_mutex);
        /* Allow all currently running kprobes to complete */
        synchronize_sched();
-
-       mutex_lock(&kprobe_mutex);
-       /* Unconditionally unregister the page_fault notifier */
-       unregister_page_fault_notifier(&kprobe_page_fault_nb);
+       return;
 
 already_disabled:
        mutex_unlock(&kprobe_mutex);