diff options
| -rw-r--r-- | include/asm-i386/kprobes.h | 1 | ||||
| -rw-r--r-- | include/asm-ia64/kprobes.h | 1 | ||||
| -rw-r--r-- | include/asm-powerpc/kprobes.h | 2 | ||||
| -rw-r--r-- | include/asm-sparc64/kprobes.h | 1 | ||||
| -rw-r--r-- | include/asm-x86_64/kprobes.h | 1 | ||||
| -rw-r--r-- | kernel/kprobes.c | 30 |
6 files changed, 29 insertions, 7 deletions
diff --git a/include/asm-i386/kprobes.h b/include/asm-i386/kprobes.h index 57d157c5cf8..0730a20f6db 100644 --- a/include/asm-i386/kprobes.h +++ b/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/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h index 8c0fc227f0f..2418a787c40 100644 --- a/include/asm-ia64/kprobes.h +++ b/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/include/asm-powerpc/kprobes.h b/include/asm-powerpc/kprobes.h index f466bc804f4..2d0af52c823 100644 --- a/include/asm-powerpc/kprobes.h +++ b/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/include/asm-sparc64/kprobes.h b/include/asm-sparc64/kprobes.h index e9bb26f770e..15065af566c 100644 --- a/include/asm-sparc64/kprobes.h +++ b/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/include/asm-x86_64/kprobes.h b/include/asm-x86_64/kprobes.h index 98a1e95ddb9..d36febd9bb1 100644 --- a/include/asm-x86_64/kprobes.h +++ b/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/kernel/kprobes.c b/kernel/kprobes.c index 507f26e7ae7..64aab081153 100644 --- a/kernel/kprobes.c +++ b/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: @@ -553,6 +565,16 @@ 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 = { @@ -560,10 +582,6 @@ static struct notifier_block kprobe_exceptions_nb = { .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; } |