X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=kernel%2Fkprobes.c;h=3bb71e63a37e0bfa47217c99b2b5e6dbe0a8f2d5;hb=f8f46da3b4cbb03b43a102b1eb92b63419e10f90;hp=90c0e82b650c09d2a6c8ed2af37318a7c6afd414;hpb=8644d2a42bdba2d513f71c07eaf1b6f9b718b8eb;p=powerpc.git diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 90c0e82b65..3bb71e63a3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -32,11 +32,12 @@ * added function-return probes. */ #include -#include #include #include +#include #include #include +#include #include #include #include @@ -47,9 +48,9 @@ static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; -unsigned int kprobe_cpu = NR_CPUS; -static DEFINE_SPINLOCK(kprobe_lock); -static struct kprobe *curr_kprobe; +static DEFINE_SPINLOCK(kprobe_lock); /* Protects kprobe_table */ +DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */ +static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; /* * kprobe->ainsn.insn points to the copy of the instruction to be @@ -72,7 +73,7 @@ static struct hlist_head kprobe_insn_pages; * get_insn_slot() - Find a slot on an executable page for an instruction. * We allocate an executable page if there's no room on existing ones. */ -kprobe_opcode_t *get_insn_slot(void) +kprobe_opcode_t __kprobes *get_insn_slot(void) { struct kprobe_insn_page *kip; struct hlist_node *pos; @@ -117,7 +118,7 @@ kprobe_opcode_t *get_insn_slot(void) return kip->insns; } -void free_insn_slot(kprobe_opcode_t *slot) +void __kprobes free_insn_slot(kprobe_opcode_t *slot) { struct kprobe_insn_page *kip; struct hlist_node *pos; @@ -151,28 +152,31 @@ void free_insn_slot(kprobe_opcode_t *slot) } } -/* Locks kprobe: irqs must be disabled */ -void lock_kprobes(void) +/* We have preemption disabled.. so it is safe to use __ versions */ +static inline void set_kprobe_instance(struct kprobe *kp) { - spin_lock(&kprobe_lock); - kprobe_cpu = smp_processor_id(); + __get_cpu_var(kprobe_instance) = kp; } -void unlock_kprobes(void) +static inline void reset_kprobe_instance(void) { - kprobe_cpu = NR_CPUS; - spin_unlock(&kprobe_lock); + __get_cpu_var(kprobe_instance) = NULL; } -/* You have to be holding the kprobe_lock */ -struct kprobe *get_kprobe(void *addr) +/* + * This routine is called either: + * - under the kprobe_lock spinlock - during kprobe_[un]register() + * OR + * - with preemption disabled - from arch/xxx/kernel/kprobes.c + */ +struct kprobe __kprobes *get_kprobe(void *addr) { struct hlist_head *head; struct hlist_node *node; + struct kprobe *p; head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; - hlist_for_each(node, head) { - struct kprobe *p = hlist_entry(node, struct kprobe, hlist); + hlist_for_each_entry_rcu(p, node, head, hlist) { if (p->addr == addr) return p; } @@ -183,64 +187,80 @@ struct kprobe *get_kprobe(void *addr) * Aggregate handlers for multiple kprobes support - these handlers * take care of invoking the individual kprobe handlers on p->list */ -static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) +static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) { struct kprobe *kp; - list_for_each_entry(kp, &p->list, list) { + list_for_each_entry_rcu(kp, &p->list, list) { if (kp->pre_handler) { - curr_kprobe = kp; + set_kprobe_instance(kp); if (kp->pre_handler(kp, regs)) return 1; } - curr_kprobe = NULL; + reset_kprobe_instance(); } return 0; } -static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, - unsigned long flags) +static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, + unsigned long flags) { struct kprobe *kp; - list_for_each_entry(kp, &p->list, list) { + list_for_each_entry_rcu(kp, &p->list, list) { if (kp->post_handler) { - curr_kprobe = kp; + set_kprobe_instance(kp); kp->post_handler(kp, regs, flags); - curr_kprobe = NULL; + reset_kprobe_instance(); } } return; } -static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, - int trapnr) +static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, + int trapnr) { + struct kprobe *cur = __get_cpu_var(kprobe_instance); + /* * if we faulted "during" the execution of a user specified * probe handler, invoke just that probe's fault handler */ - if (curr_kprobe && curr_kprobe->fault_handler) { - if (curr_kprobe->fault_handler(curr_kprobe, regs, trapnr)) + if (cur && cur->fault_handler) { + if (cur->fault_handler(cur, regs, trapnr)) return 1; } return 0; } -static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs) +static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) { - struct kprobe *kp = curr_kprobe; - if (curr_kprobe && kp->break_handler) { - if (kp->break_handler(kp, regs)) { - curr_kprobe = NULL; - return 1; - } + struct kprobe *cur = __get_cpu_var(kprobe_instance); + int ret = 0; + + if (cur && cur->break_handler) { + if (cur->break_handler(cur, regs)) + ret = 1; } - curr_kprobe = NULL; - return 0; + reset_kprobe_instance(); + return ret; } -struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp) +/* Walks the list and increments nmissed count for multiprobe case */ +void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) +{ + struct kprobe *kp; + if (p->pre_handler != aggr_pre_handler) { + p->nmissed++; + } else { + list_for_each_entry_rcu(kp, &p->list, list) + kp->nmissed++; + } + return; +} + +/* Called with kretprobe_lock held */ +struct kretprobe_instance __kprobes *get_free_rp_inst(struct kretprobe *rp) { struct hlist_node *node; struct kretprobe_instance *ri; @@ -249,7 +269,9 @@ struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp) return NULL; } -static struct kretprobe_instance *get_used_rp_inst(struct kretprobe *rp) +/* Called with kretprobe_lock held */ +static struct kretprobe_instance __kprobes *get_used_rp_inst(struct kretprobe + *rp) { struct hlist_node *node; struct kretprobe_instance *ri; @@ -258,7 +280,8 @@ static struct kretprobe_instance *get_used_rp_inst(struct kretprobe *rp) return NULL; } -void add_rp_inst(struct kretprobe_instance *ri) +/* Called with kretprobe_lock held */ +void __kprobes add_rp_inst(struct kretprobe_instance *ri) { /* * Remove rp inst off the free list - @@ -276,7 +299,8 @@ void add_rp_inst(struct kretprobe_instance *ri) hlist_add_head(&ri->uflist, &ri->rp->used_instances); } -void recycle_rp_inst(struct kretprobe_instance *ri) +/* Called with kretprobe_lock held */ +void __kprobes recycle_rp_inst(struct kretprobe_instance *ri) { /* remove rp inst off the rprobe_inst_table */ hlist_del(&ri->hlist); @@ -291,7 +315,7 @@ void recycle_rp_inst(struct kretprobe_instance *ri) kfree(ri); } -struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk) +struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk) { return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)]; } @@ -302,32 +326,36 @@ struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk) * 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) +void __kprobes 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); + spin_lock_irqsave(&kretprobe_lock, flags); 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); + spin_unlock_irqrestore(&kretprobe_lock, flags); } /* * This kprobe pre_handler is registered with every kretprobe. When probe * hits it will set up the return probe. */ -static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) +static int __kprobes pre_handler_kretprobe(struct kprobe *p, + struct pt_regs *regs) { struct kretprobe *rp = container_of(p, struct kretprobe, kp); + unsigned long flags = 0; /*TODO: consider to only swap the RA after the last pre_handler fired */ + spin_lock_irqsave(&kretprobe_lock, flags); arch_prepare_kretprobe(rp, regs); + spin_unlock_irqrestore(&kretprobe_lock, flags); return 0; } @@ -353,18 +381,18 @@ static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) * Add the new probe to old_p->list. Fail if this is the * second jprobe at the address - two jprobes can't coexist */ -static int add_new_kprobe(struct kprobe *old_p, struct kprobe *p) +static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) { struct kprobe *kp; if (p->break_handler) { - list_for_each_entry(kp, &old_p->list, list) { + list_for_each_entry_rcu(kp, &old_p->list, list) { if (kp->break_handler) return -EEXIST; } - list_add_tail(&p->list, &old_p->list); + list_add_tail_rcu(&p->list, &old_p->list); } else - list_add(&p->list, &old_p->list); + list_add_rcu(&p->list, &old_p->list); return 0; } @@ -382,20 +410,18 @@ static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) ap->break_handler = aggr_break_handler; INIT_LIST_HEAD(&ap->list); - list_add(&p->list, &ap->list); + list_add_rcu(&p->list, &ap->list); - INIT_HLIST_NODE(&ap->hlist); - hlist_del(&p->hlist); - hlist_add_head(&ap->hlist, - &kprobe_table[hash_ptr(ap->addr, KPROBE_HASH_BITS)]); + hlist_replace_rcu(&p->hlist, &ap->hlist); } /* * This is the second or subsequent kprobe at the address - handle * the intricacies - * TODO: Move kcalloc outside the spinlock + * TODO: Move kcalloc outside the spin_lock */ -static int register_aggr_kprobe(struct kprobe *old_p, struct kprobe *p) +static int __kprobes register_aggr_kprobe(struct kprobe *old_p, + struct kprobe *p) { int ret = 0; struct kprobe *ap; @@ -418,7 +444,7 @@ static int register_aggr_kprobe(struct kprobe *old_p, struct kprobe *p) static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags) { arch_disarm_kprobe(p); - hlist_del(&p->hlist); + hlist_del_rcu(&p->hlist); spin_unlock_irqrestore(&kprobe_lock, flags); arch_remove_kprobe(p); } @@ -426,26 +452,42 @@ static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags) static inline void cleanup_aggr_kprobe(struct kprobe *old_p, struct kprobe *p, unsigned long flags) { - list_del(&p->list); - if (list_empty(&old_p->list)) { + list_del_rcu(&p->list); + if (list_empty(&old_p->list)) cleanup_kprobe(old_p, flags); - kfree(old_p); - } else + else spin_unlock_irqrestore(&kprobe_lock, flags); } -int register_kprobe(struct kprobe *p) +static int __kprobes in_kprobes_functions(unsigned long addr) +{ + if (addr >= (unsigned long)__kprobes_text_start + && addr < (unsigned long)__kprobes_text_end) + return -EINVAL; + return 0; +} + +int __kprobes register_kprobe(struct kprobe *p) { int ret = 0; unsigned long flags = 0; struct kprobe *old_p; + struct module *mod; + + if ((!kernel_text_address((unsigned long) p->addr)) || + in_kprobes_functions((unsigned long) p->addr)) + return -EINVAL; - if ((ret = arch_prepare_kprobe(p)) != 0) { + if ((mod = module_text_address((unsigned long) p->addr)) && + (unlikely(!try_module_get(mod)))) + return -EINVAL; + + if ((ret = arch_prepare_kprobe(p)) != 0) goto rm_kprobe; - } + + p->nmissed = 0; spin_lock_irqsave(&kprobe_lock, flags); old_p = get_kprobe(p->addr); - p->nmissed = 0; if (old_p) { ret = register_aggr_kprobe(old_p, p); goto out; @@ -453,7 +495,7 @@ int register_kprobe(struct kprobe *p) arch_copy_kprobe(p); INIT_HLIST_NODE(&p->hlist); - hlist_add_head(&p->hlist, + hlist_add_head_rcu(&p->hlist, &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); arch_arm_kprobe(p); @@ -463,21 +505,34 @@ out: rm_kprobe: if (ret == -EEXIST) arch_remove_kprobe(p); + if (ret && mod) + module_put(mod); return ret; } -void unregister_kprobe(struct kprobe *p) +void __kprobes unregister_kprobe(struct kprobe *p) { unsigned long flags; struct kprobe *old_p; + struct module *mod; spin_lock_irqsave(&kprobe_lock, flags); old_p = get_kprobe(p->addr); if (old_p) { + /* cleanup_*_kprobe() does the spin_unlock_irqrestore */ if (old_p->pre_handler == aggr_pre_handler) cleanup_aggr_kprobe(old_p, p, flags); else cleanup_kprobe(p, flags); + + synchronize_sched(); + + if ((mod = module_text_address((unsigned long)p->addr))) + module_put(mod); + + if (old_p->pre_handler == aggr_pre_handler && + list_empty(&old_p->list)) + kfree(old_p); } else spin_unlock_irqrestore(&kprobe_lock, flags); } @@ -487,7 +542,7 @@ static struct notifier_block kprobe_exceptions_nb = { .priority = 0x7fffffff /* we need to notified first */ }; -int register_jprobe(struct jprobe *jp) +int __kprobes register_jprobe(struct jprobe *jp) { /* Todo: Verify probepoint is a function entry point */ jp->kp.pre_handler = setjmp_pre_handler; @@ -496,14 +551,14 @@ int register_jprobe(struct jprobe *jp) return register_kprobe(&jp->kp); } -void unregister_jprobe(struct jprobe *jp) +void __kprobes unregister_jprobe(struct jprobe *jp) { unregister_kprobe(&jp->kp); } #ifdef ARCH_SUPPORTS_KRETPROBES -int register_kretprobe(struct kretprobe *rp) +int __kprobes register_kretprobe(struct kretprobe *rp) { int ret = 0; struct kretprobe_instance *inst; @@ -540,27 +595,27 @@ int register_kretprobe(struct kretprobe *rp) #else /* ARCH_SUPPORTS_KRETPROBES */ -int register_kretprobe(struct kretprobe *rp) +int __kprobes register_kretprobe(struct kretprobe *rp) { return -ENOSYS; } #endif /* ARCH_SUPPORTS_KRETPROBES */ -void unregister_kretprobe(struct kretprobe *rp) +void __kprobes unregister_kretprobe(struct kretprobe *rp) { unsigned long flags; struct kretprobe_instance *ri; unregister_kprobe(&rp->kp); /* No race here */ - spin_lock_irqsave(&kprobe_lock, flags); + spin_lock_irqsave(&kretprobe_lock, flags); free_rp_inst(rp); while ((ri = get_used_rp_inst(rp)) != NULL) { ri->rp = NULL; hlist_del(&ri->uflist); } - spin_unlock_irqrestore(&kprobe_lock, flags); + spin_unlock_irqrestore(&kretprobe_lock, flags); } static int __init init_kprobes(void) @@ -574,7 +629,7 @@ static int __init init_kprobes(void) INIT_HLIST_HEAD(&kretprobe_inst_table[i]); } - err = arch_init(); + err = arch_init_kprobes(); if (!err) err = register_die_notifier(&kprobe_exceptions_nb);