| /* |
| * Kernel Probes (KProbes) |
| * kernel/kprobes.c |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| * |
| * Copyright (C) IBM Corporation, 2002, 2004 |
| * |
| * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel |
| * Probes initial implementation (includes suggestions from |
| * Rusty Russell). |
| * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with |
| * hlists and exceptions notifier as suggested by Andi Kleen. |
| * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes |
| * interface to access function arguments. |
| * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes |
| * exceptions notifier to be first on the priority list. |
| * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston |
| * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi |
| * <prasanna@in.ibm.com> added function-return probes. |
| */ |
| #include <linux/kprobes.h> |
| #include <linux/hash.h> |
| #include <linux/init.h> |
| #include <linux/slab.h> |
| #include <linux/stddef.h> |
| #include <linux/export.h> |
| #include <linux/moduleloader.h> |
| #include <linux/kallsyms.h> |
| #include <linux/freezer.h> |
| #include <linux/seq_file.h> |
| #include <linux/debugfs.h> |
| #include <linux/sysctl.h> |
| #include <linux/kdebug.h> |
| #include <linux/memory.h> |
| #include <linux/ftrace.h> |
| #include <linux/cpu.h> |
| #include <linux/jump_label.h> |
| |
| #include <asm-generic/sections.h> |
| #include <asm/cacheflush.h> |
| #include <asm/errno.h> |
| #include <asm/uaccess.h> |
| |
| #define KPROBE_HASH_BITS 6 |
| #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) |
| |
| |
| /* |
| * Some oddball architectures like 64bit powerpc have function descriptors |
| * so this must be overridable. |
| */ |
| #ifndef kprobe_lookup_name |
| #define kprobe_lookup_name(name, addr) \ |
| addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) |
| #endif |
| |
| static int kprobes_initialized; |
| static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
| static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
| |
| /* NOTE: change this value only with kprobe_mutex held */ |
| static bool kprobes_all_disarmed; |
| |
| /* This protects kprobe_table and optimizing_list */ |
| static DEFINE_MUTEX(kprobe_mutex); |
| static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
| static struct { |
| raw_spinlock_t lock ____cacheline_aligned_in_smp; |
| } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
| |
| static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) |
| { |
| return &(kretprobe_table_locks[hash].lock); |
| } |
| |
| /* |
| * Normally, functions that we'd want to prohibit kprobes in, are marked |
| * __kprobes. But, there are cases where such functions already belong to |
| * a different section (__sched for preempt_schedule) |
| * |
| * For such cases, we now have a blacklist |
| */ |
| static struct kprobe_blackpoint kprobe_blacklist[] = { |
| {"preempt_schedule",}, |
| {"native_get_debugreg",}, |
| {"irq_entries_start",}, |
| {"common_interrupt",}, |
| {"mcount",}, /* mcount can be called from everywhere */ |
| {NULL} /* Terminator */ |
| }; |
| |
| #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
| /* |
| * kprobe->ainsn.insn points to the copy of the instruction to be |
| * single-stepped. x86_64, POWER4 and above have no-exec support and |
| * stepping on the instruction on a vmalloced/kmalloced/data page |
| * is a recipe for disaster |
| */ |
| struct kprobe_insn_page { |
| struct list_head list; |
| kprobe_opcode_t *insns; /* Page of instruction slots */ |
| int nused; |
| int ngarbage; |
| char slot_used[]; |
| }; |
| |
| #define KPROBE_INSN_PAGE_SIZE(slots) \ |
| (offsetof(struct kprobe_insn_page, slot_used) + \ |
| (sizeof(char) * (slots))) |
| |
| struct kprobe_insn_cache { |
| struct list_head pages; /* list of kprobe_insn_page */ |
| size_t insn_size; /* size of instruction slot */ |
| int nr_garbage; |
| }; |
| |
| static int slots_per_page(struct kprobe_insn_cache *c) |
| { |
| return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); |
| } |
| |
| enum kprobe_slot_state { |
| SLOT_CLEAN = 0, |
| SLOT_DIRTY = 1, |
| SLOT_USED = 2, |
| }; |
| |
| static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */ |
| static struct kprobe_insn_cache kprobe_insn_slots = { |
| .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
| .insn_size = MAX_INSN_SIZE, |
| .nr_garbage = 0, |
| }; |
| static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c); |
| |
| /** |
| * __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. |
| */ |
| static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) |
| { |
| struct kprobe_insn_page *kip; |
| |
| retry: |
| list_for_each_entry(kip, &c->pages, list) { |
| if (kip->nused < slots_per_page(c)) { |
| int i; |
| for (i = 0; i < slots_per_page(c); i++) { |
| if (kip->slot_used[i] == SLOT_CLEAN) { |
| kip->slot_used[i] = SLOT_USED; |
| kip->nused++; |
| return kip->insns + (i * c->insn_size); |
| } |
| } |
| /* kip->nused is broken. Fix it. */ |
| kip->nused = slots_per_page(c); |
| WARN_ON(1); |
| } |
| } |
| |
| /* If there are any garbage slots, collect it and try again. */ |
| if (c->nr_garbage && collect_garbage_slots(c) == 0) |
| goto retry; |
| |
| /* All out of space. Need to allocate a new page. */ |
| kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); |
| if (!kip) |
| return NULL; |
| |
| /* |
| * Use module_alloc so this page is within +/- 2GB of where the |
| * kernel image and loaded module images reside. This is required |
| * so x86_64 can correctly handle the %rip-relative fixups. |
| */ |
| kip->insns = module_alloc(PAGE_SIZE); |
| if (!kip->insns) { |
| kfree(kip); |
| return NULL; |
| } |
| INIT_LIST_HEAD(&kip->list); |
| memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
| kip->slot_used[0] = SLOT_USED; |
| kip->nused = 1; |
| kip->ngarbage = 0; |
| list_add(&kip->list, &c->pages); |
| return kip->insns; |
| } |
| |
| |
| kprobe_opcode_t __kprobes *get_insn_slot(void) |
| { |
| kprobe_opcode_t *ret = NULL; |
| |
| mutex_lock(&kprobe_insn_mutex); |
| ret = __get_insn_slot(&kprobe_insn_slots); |
| mutex_unlock(&kprobe_insn_mutex); |
| |
| return ret; |
| } |
| |
| /* Return 1 if all garbages are collected, otherwise 0. */ |
| static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) |
| { |
| kip->slot_used[idx] = SLOT_CLEAN; |
| kip->nused--; |
| if (kip->nused == 0) { |
| /* |
| * Page is no longer in use. Free it unless |
| * it's the last one. We keep the last one |
| * so as not to have to set it up again the |
| * next time somebody inserts a probe. |
| */ |
| if (!list_is_singular(&kip->list)) { |
| list_del(&kip->list); |
| module_free(NULL, kip->insns); |
| kfree(kip); |
| } |
| return 1; |
| } |
| return 0; |
| } |
| |
| static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c) |
| { |
| struct kprobe_insn_page *kip, *next; |
| |
| /* Ensure no-one is interrupted on the garbages */ |
| synchronize_sched(); |
| |
| list_for_each_entry_safe(kip, next, &c->pages, list) { |
| int i; |
| if (kip->ngarbage == 0) |
| continue; |
| kip->ngarbage = 0; /* we will collect all garbages */ |
| for (i = 0; i < slots_per_page(c); i++) { |
| if (kip->slot_used[i] == SLOT_DIRTY && |
| collect_one_slot(kip, i)) |
| break; |
| } |
| } |
| c->nr_garbage = 0; |
| return 0; |
| } |
| |
| static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, |
| kprobe_opcode_t *slot, int dirty) |
| { |
| struct kprobe_insn_page *kip; |
| |
| list_for_each_entry(kip, &c->pages, list) { |
| long idx = ((long)slot - (long)kip->insns) / |
| (c->insn_size * sizeof(kprobe_opcode_t)); |
| if (idx >= 0 && idx < slots_per_page(c)) { |
| WARN_ON(kip->slot_used[idx] != SLOT_USED); |
| if (dirty) { |
| kip->slot_used[idx] = SLOT_DIRTY; |
| kip->ngarbage++; |
| if (++c->nr_garbage > slots_per_page(c)) |
| collect_garbage_slots(c); |
| } else |
| collect_one_slot(kip, idx); |
| return; |
| } |
| } |
| /* Could not free this slot. */ |
| WARN_ON(1); |
| } |
| |
| void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) |
| { |
| mutex_lock(&kprobe_insn_mutex); |
| __free_insn_slot(&kprobe_insn_slots, slot, dirty); |
| mutex_unlock(&kprobe_insn_mutex); |
| } |
| #ifdef CONFIG_OPTPROBES |
| /* For optimized_kprobe buffer */ |
| static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */ |
| static struct kprobe_insn_cache kprobe_optinsn_slots = { |
| .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
| /* .insn_size is initialized later */ |
| .nr_garbage = 0, |
| }; |
| /* Get a slot for optimized_kprobe buffer */ |
| kprobe_opcode_t __kprobes *get_optinsn_slot(void) |
| { |
| kprobe_opcode_t *ret = NULL; |
| |
| mutex_lock(&kprobe_optinsn_mutex); |
| ret = __get_insn_slot(&kprobe_optinsn_slots); |
| mutex_unlock(&kprobe_optinsn_mutex); |
| |
| return ret; |
| } |
| |
| void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty) |
| { |
| mutex_lock(&kprobe_optinsn_mutex); |
| __free_insn_slot(&kprobe_optinsn_slots, slot, dirty); |
| mutex_unlock(&kprobe_optinsn_mutex); |
| } |
| #endif |
| #endif |
| |
| /* We have preemption disabled.. so it is safe to use __ versions */ |
| static inline void set_kprobe_instance(struct kprobe *kp) |
| { |
| __this_cpu_write(kprobe_instance, kp); |
| } |
| |
| static inline void reset_kprobe_instance(void) |
| { |
| __this_cpu_write(kprobe_instance, NULL); |
| } |
| |
| /* |
| * This routine is called either: |
| * - under the kprobe_mutex - 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_entry_rcu(p, node, head, hlist) { |
| if (p->addr == addr) |
| return p; |
| } |
| |
| return NULL; |
| } |
| |
| static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
| |
| /* Return true if the kprobe is an aggregator */ |
| static inline int kprobe_aggrprobe(struct kprobe *p) |
| { |
| return p->pre_handler == aggr_pre_handler; |
| } |
| |
| /* Return true(!0) if the kprobe is unused */ |
| static inline int kprobe_unused(struct kprobe *p) |
| { |
| return kprobe_aggrprobe(p) && kprobe_disabled(p) && |
| list_empty(&p->list); |
| } |
| |
| /* |
| * Keep all fields in the kprobe consistent |
| */ |
| static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
| { |
| memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
| memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); |
| } |
| |
| #ifdef CONFIG_OPTPROBES |
| /* NOTE: change this value only with kprobe_mutex held */ |
| static bool kprobes_allow_optimization; |
| |
| /* |
| * Call all pre_handler on the list, but ignores its return value. |
| * This must be called from arch-dep optimized caller. |
| */ |
| void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct kprobe *kp; |
| |
| list_for_each_entry_rcu(kp, &p->list, list) { |
| if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
| set_kprobe_instance(kp); |
| kp->pre_handler(kp, regs); |
| } |
| reset_kprobe_instance(); |
| } |
| } |
| |
| /* Free optimized instructions and optimized_kprobe */ |
| static __kprobes void free_aggr_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| arch_remove_optimized_kprobe(op); |
| arch_remove_kprobe(p); |
| kfree(op); |
| } |
| |
| /* Return true(!0) if the kprobe is ready for optimization. */ |
| static inline int kprobe_optready(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| if (kprobe_aggrprobe(p)) { |
| op = container_of(p, struct optimized_kprobe, kp); |
| return arch_prepared_optinsn(&op->optinsn); |
| } |
| |
| return 0; |
| } |
| |
| /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */ |
| static inline int kprobe_disarmed(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ |
| if (!kprobe_aggrprobe(p)) |
| return kprobe_disabled(p); |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| |
| return kprobe_disabled(p) && list_empty(&op->list); |
| } |
| |
| /* Return true(!0) if the probe is queued on (un)optimizing lists */ |
| static int __kprobes kprobe_queued(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| if (kprobe_aggrprobe(p)) { |
| op = container_of(p, struct optimized_kprobe, kp); |
| if (!list_empty(&op->list)) |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * Return an optimized kprobe whose optimizing code replaces |
| * instructions including addr (exclude breakpoint). |
| */ |
| static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr) |
| { |
| int i; |
| struct kprobe *p = NULL; |
| struct optimized_kprobe *op; |
| |
| /* Don't check i == 0, since that is a breakpoint case. */ |
| for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) |
| p = get_kprobe((void *)(addr - i)); |
| |
| if (p && kprobe_optready(p)) { |
| op = container_of(p, struct optimized_kprobe, kp); |
| if (arch_within_optimized_kprobe(op, addr)) |
| return p; |
| } |
| |
| return NULL; |
| } |
| |
| /* Optimization staging list, protected by kprobe_mutex */ |
| static LIST_HEAD(optimizing_list); |
| static LIST_HEAD(unoptimizing_list); |
| |
| static void kprobe_optimizer(struct work_struct *work); |
| static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); |
| static DECLARE_COMPLETION(optimizer_comp); |
| #define OPTIMIZE_DELAY 5 |
| |
| /* |
| * Optimize (replace a breakpoint with a jump) kprobes listed on |
| * optimizing_list. |
| */ |
| static __kprobes void do_optimize_kprobes(void) |
| { |
| /* Optimization never be done when disarmed */ |
| if (kprobes_all_disarmed || !kprobes_allow_optimization || |
| list_empty(&optimizing_list)) |
| return; |
| |
| /* |
| * The optimization/unoptimization refers online_cpus via |
| * stop_machine() and cpu-hotplug modifies online_cpus. |
| * And same time, text_mutex will be held in cpu-hotplug and here. |
| * This combination can cause a deadlock (cpu-hotplug try to lock |
| * text_mutex but stop_machine can not be done because online_cpus |
| * has been changed) |
| * To avoid this deadlock, we need to call get_online_cpus() |
| * for preventing cpu-hotplug outside of text_mutex locking. |
| */ |
| get_online_cpus(); |
| mutex_lock(&text_mutex); |
| arch_optimize_kprobes(&optimizing_list); |
| mutex_unlock(&text_mutex); |
| put_online_cpus(); |
| } |
| |
| /* |
| * Unoptimize (replace a jump with a breakpoint and remove the breakpoint |
| * if need) kprobes listed on unoptimizing_list. |
| */ |
| static __kprobes void do_unoptimize_kprobes(struct list_head *free_list) |
| { |
| struct optimized_kprobe *op, *tmp; |
| |
| /* Unoptimization must be done anytime */ |
| if (list_empty(&unoptimizing_list)) |
| return; |
| |
| /* Ditto to do_optimize_kprobes */ |
| get_online_cpus(); |
| mutex_lock(&text_mutex); |
| arch_unoptimize_kprobes(&unoptimizing_list, free_list); |
| /* Loop free_list for disarming */ |
| list_for_each_entry_safe(op, tmp, free_list, list) { |
| /* Disarm probes if marked disabled */ |
| if (kprobe_disabled(&op->kp)) |
| arch_disarm_kprobe(&op->kp); |
| if (kprobe_unused(&op->kp)) { |
| /* |
| * Remove unused probes from hash list. After waiting |
| * for synchronization, these probes are reclaimed. |
| * (reclaiming is done by do_free_cleaned_kprobes.) |
| */ |
| hlist_del_rcu(&op->kp.hlist); |
| } else |
| list_del_init(&op->list); |
| } |
| mutex_unlock(&text_mutex); |
| put_online_cpus(); |
| } |
| |
| /* Reclaim all kprobes on the free_list */ |
| static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list) |
| { |
| struct optimized_kprobe *op, *tmp; |
| |
| list_for_each_entry_safe(op, tmp, free_list, list) { |
| BUG_ON(!kprobe_unused(&op->kp)); |
| list_del_init(&op->list); |
| free_aggr_kprobe(&op->kp); |
| } |
| } |
| |
| /* Start optimizer after OPTIMIZE_DELAY passed */ |
| static __kprobes void kick_kprobe_optimizer(void) |
| { |
| if (!delayed_work_pending(&optimizing_work)) |
| schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
| } |
| |
| /* Kprobe jump optimizer */ |
| static __kprobes void kprobe_optimizer(struct work_struct *work) |
| { |
| LIST_HEAD(free_list); |
| |
| /* Lock modules while optimizing kprobes */ |
| mutex_lock(&module_mutex); |
| mutex_lock(&kprobe_mutex); |
| |
| /* |
| * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
| * kprobes before waiting for quiesence period. |
| */ |
| do_unoptimize_kprobes(&free_list); |
| |
| /* |
| * Step 2: Wait for quiesence period to ensure all running interrupts |
| * are done. Because optprobe may modify multiple instructions |
| * there is a chance that Nth instruction is interrupted. In that |
| * case, running interrupt can return to 2nd-Nth byte of jump |
| * instruction. This wait is for avoiding it. |
| */ |
| synchronize_sched(); |
| |
| /* Step 3: Optimize kprobes after quiesence period */ |
| do_optimize_kprobes(); |
| |
| /* Step 4: Free cleaned kprobes after quiesence period */ |
| do_free_cleaned_kprobes(&free_list); |
| |
| mutex_unlock(&kprobe_mutex); |
| mutex_unlock(&module_mutex); |
| |
| /* Step 5: Kick optimizer again if needed */ |
| if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
| kick_kprobe_optimizer(); |
| else |
| /* Wake up all waiters */ |
| complete_all(&optimizer_comp); |
| } |
| |
| /* Wait for completing optimization and unoptimization */ |
| static __kprobes void wait_for_kprobe_optimizer(void) |
| { |
| if (delayed_work_pending(&optimizing_work)) |
| wait_for_completion(&optimizer_comp); |
| } |
| |
| /* Optimize kprobe if p is ready to be optimized */ |
| static __kprobes void optimize_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| /* Check if the kprobe is disabled or not ready for optimization. */ |
| if (!kprobe_optready(p) || !kprobes_allow_optimization || |
| (kprobe_disabled(p) || kprobes_all_disarmed)) |
| return; |
| |
| /* Both of break_handler and post_handler are not supported. */ |
| if (p->break_handler || p->post_handler) |
| return; |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| |
| /* Check there is no other kprobes at the optimized instructions */ |
| if (arch_check_optimized_kprobe(op) < 0) |
| return; |
| |
| /* Check if it is already optimized. */ |
| if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) |
| return; |
| op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
| |
| if (!list_empty(&op->list)) |
| /* This is under unoptimizing. Just dequeue the probe */ |
| list_del_init(&op->list); |
| else { |
| list_add(&op->list, &optimizing_list); |
| kick_kprobe_optimizer(); |
| } |
| } |
| |
| /* Short cut to direct unoptimizing */ |
| static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op) |
| { |
| get_online_cpus(); |
| arch_unoptimize_kprobe(op); |
| put_online_cpus(); |
| if (kprobe_disabled(&op->kp)) |
| arch_disarm_kprobe(&op->kp); |
| } |
| |
| /* Unoptimize a kprobe if p is optimized */ |
| static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force) |
| { |
| struct optimized_kprobe *op; |
| |
| if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
| return; /* This is not an optprobe nor optimized */ |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| if (!kprobe_optimized(p)) { |
| /* Unoptimized or unoptimizing case */ |
| if (force && !list_empty(&op->list)) { |
| /* |
| * Only if this is unoptimizing kprobe and forced, |
| * forcibly unoptimize it. (No need to unoptimize |
| * unoptimized kprobe again :) |
| */ |
| list_del_init(&op->list); |
| force_unoptimize_kprobe(op); |
| } |
| return; |
| } |
| |
| op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
| if (!list_empty(&op->list)) { |
| /* Dequeue from the optimization queue */ |
| list_del_init(&op->list); |
| return; |
| } |
| /* Optimized kprobe case */ |
| if (force) |
| /* Forcibly update the code: this is a special case */ |
| force_unoptimize_kprobe(op); |
| else { |
| list_add(&op->list, &unoptimizing_list); |
| kick_kprobe_optimizer(); |
| } |
| } |
| |
| /* Cancel unoptimizing for reusing */ |
| static void reuse_unused_kprobe(struct kprobe *ap) |
| { |
| struct optimized_kprobe *op; |
| |
| BUG_ON(!kprobe_unused(ap)); |
| /* |
| * Unused kprobe MUST be on the way of delayed unoptimizing (means |
| * there is still a relative jump) and disabled. |
| */ |
| op = container_of(ap, struct optimized_kprobe, kp); |
| if (unlikely(list_empty(&op->list))) |
| printk(KERN_WARNING "Warning: found a stray unused " |
| "aggrprobe@%p\n", ap->addr); |
| /* Enable the probe again */ |
| ap->flags &= ~KPROBE_FLAG_DISABLED; |
| /* Optimize it again (remove from op->list) */ |
| BUG_ON(!kprobe_optready(ap)); |
| optimize_kprobe(ap); |
| } |
| |
| /* Remove optimized instructions */ |
| static void __kprobes kill_optimized_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| if (!list_empty(&op->list)) |
| /* Dequeue from the (un)optimization queue */ |
| list_del_init(&op->list); |
| |
| op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
| /* Don't touch the code, because it is already freed. */ |
| arch_remove_optimized_kprobe(op); |
| } |
| |
| /* Try to prepare optimized instructions */ |
| static __kprobes void prepare_optimized_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| op = container_of(p, struct optimized_kprobe, kp); |
| arch_prepare_optimized_kprobe(op); |
| } |
| |
| /* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
| static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
| { |
| struct optimized_kprobe *op; |
| |
| op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); |
| if (!op) |
| return NULL; |
| |
| INIT_LIST_HEAD(&op->list); |
| op->kp.addr = p->addr; |
| arch_prepare_optimized_kprobe(op); |
| |
| return &op->kp; |
| } |
| |
| static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
| |
| /* |
| * Prepare an optimized_kprobe and optimize it |
| * NOTE: p must be a normal registered kprobe |
| */ |
| static __kprobes void try_to_optimize_kprobe(struct kprobe *p) |
| { |
| struct kprobe *ap; |
| struct optimized_kprobe *op; |
| |
| ap = alloc_aggr_kprobe(p); |
| if (!ap) |
| return; |
| |
| op = container_of(ap, struct optimized_kprobe, kp); |
| if (!arch_prepared_optinsn(&op->optinsn)) { |
| /* If failed to setup optimizing, fallback to kprobe */ |
| arch_remove_optimized_kprobe(op); |
| kfree(op); |
| return; |
| } |
| |
| init_aggr_kprobe(ap, p); |
| optimize_kprobe(ap); |
| } |
| |
| #ifdef CONFIG_SYSCTL |
| /* This should be called with kprobe_mutex locked */ |
| static void __kprobes optimize_all_kprobes(void) |
| { |
| struct hlist_head *head; |
| struct hlist_node *node; |
| struct kprobe *p; |
| unsigned int i; |
| |
| /* If optimization is already allowed, just return */ |
| if (kprobes_allow_optimization) |
| return; |
| |
| kprobes_allow_optimization = true; |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| hlist_for_each_entry_rcu(p, node, head, hlist) |
| if (!kprobe_disabled(p)) |
| optimize_kprobe(p); |
| } |
| printk(KERN_INFO "Kprobes globally optimized\n"); |
| } |
| |
| /* This should be called with kprobe_mutex locked */ |
| static void __kprobes unoptimize_all_kprobes(void) |
| { |
| struct hlist_head *head; |
| struct hlist_node *node; |
| struct kprobe *p; |
| unsigned int i; |
| |
| /* If optimization is already prohibited, just return */ |
| if (!kprobes_allow_optimization) |
| return; |
| |
| kprobes_allow_optimization = false; |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| hlist_for_each_entry_rcu(p, node, head, hlist) { |
| if (!kprobe_disabled(p)) |
| unoptimize_kprobe(p, false); |
| } |
| } |
| /* Wait for unoptimizing completion */ |
| wait_for_kprobe_optimizer(); |
| printk(KERN_INFO "Kprobes globally unoptimized\n"); |
| } |
| |
| int sysctl_kprobes_optimization; |
| int proc_kprobes_optimization_handler(struct ctl_table *table, int write, |
| void __user *buffer, size_t *length, |
| loff_t *ppos) |
| { |
| int ret; |
| |
| mutex_lock(&kprobe_mutex); |
| sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
| ret = proc_dointvec_minmax(table, write, buffer, length, ppos); |
| |
| if (sysctl_kprobes_optimization) |
| optimize_all_kprobes(); |
| else |
| unoptimize_all_kprobes(); |
| mutex_unlock(&kprobe_mutex); |
| |
| return ret; |
| } |
| #endif /* CONFIG_SYSCTL */ |
| |
| /* Put a breakpoint for a probe. Must be called with text_mutex locked */ |
| static void __kprobes __arm_kprobe(struct kprobe *p) |
| { |
| struct kprobe *_p; |
| |
| /* Check collision with other optimized kprobes */ |
| _p = get_optimized_kprobe((unsigned long)p->addr); |
| if (unlikely(_p)) |
| /* Fallback to unoptimized kprobe */ |
| unoptimize_kprobe(_p, true); |
| |
| arch_arm_kprobe(p); |
| optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ |
| } |
| |
| /* Remove the breakpoint of a probe. Must be called with text_mutex locked */ |
| static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt) |
| { |
| struct kprobe *_p; |
| |
| unoptimize_kprobe(p, false); /* Try to unoptimize */ |
| |
| if (!kprobe_queued(p)) { |
| arch_disarm_kprobe(p); |
| /* If another kprobe was blocked, optimize it. */ |
| _p = get_optimized_kprobe((unsigned long)p->addr); |
| if (unlikely(_p) && reopt) |
| optimize_kprobe(_p); |
| } |
| /* TODO: reoptimize others after unoptimized this probe */ |
| } |
| |
| #else /* !CONFIG_OPTPROBES */ |
| |
| #define optimize_kprobe(p) do {} while (0) |
| #define unoptimize_kprobe(p, f) do {} while (0) |
| #define kill_optimized_kprobe(p) do {} while (0) |
| #define prepare_optimized_kprobe(p) do {} while (0) |
| #define try_to_optimize_kprobe(p) do {} while (0) |
| #define __arm_kprobe(p) arch_arm_kprobe(p) |
| #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
| #define kprobe_disarmed(p) kprobe_disabled(p) |
| #define wait_for_kprobe_optimizer() do {} while (0) |
| |
| /* There should be no unused kprobes can be reused without optimization */ |
| static void reuse_unused_kprobe(struct kprobe *ap) |
| { |
| printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); |
| BUG_ON(kprobe_unused(ap)); |
| } |
| |
| static __kprobes void free_aggr_kprobe(struct kprobe *p) |
| { |
| arch_remove_kprobe(p); |
| kfree(p); |
| } |
| |
| static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
| { |
| return kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
| } |
| #endif /* CONFIG_OPTPROBES */ |
| |
| /* Arm a kprobe with text_mutex */ |
| static void __kprobes arm_kprobe(struct kprobe *kp) |
| { |
| /* |
| * Here, since __arm_kprobe() doesn't use stop_machine(), |
| * this doesn't cause deadlock on text_mutex. So, we don't |
| * need get_online_cpus(). |
| */ |
| mutex_lock(&text_mutex); |
| __arm_kprobe(kp); |
| mutex_unlock(&text_mutex); |
| } |
| |
| /* Disarm a kprobe with text_mutex */ |
| static void __kprobes disarm_kprobe(struct kprobe *kp) |
| { |
| /* Ditto */ |
| mutex_lock(&text_mutex); |
| __disarm_kprobe(kp, true); |
| mutex_unlock(&text_mutex); |
| } |
| |
| /* |
| * Aggregate handlers for multiple kprobes support - these handlers |
| * take care of invoking the individual kprobe handlers on p->list |
| */ |
| static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct kprobe *kp; |
| |
| list_for_each_entry_rcu(kp, &p->list, list) { |
| if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
| set_kprobe_instance(kp); |
| if (kp->pre_handler(kp, regs)) |
| return 1; |
| } |
| reset_kprobe_instance(); |
| } |
| return 0; |
| } |
| |
| static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
| unsigned long flags) |
| { |
| struct kprobe *kp; |
| |
| list_for_each_entry_rcu(kp, &p->list, list) { |
| if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
| set_kprobe_instance(kp); |
| kp->post_handler(kp, regs, flags); |
| reset_kprobe_instance(); |
| } |
| } |
| } |
| |
| static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
| int trapnr) |
| { |
| struct kprobe *cur = __this_cpu_read(kprobe_instance); |
| |
| /* |
| * if we faulted "during" the execution of a user specified |
| * probe handler, invoke just that probe's fault handler |
| */ |
| if (cur && cur->fault_handler) { |
| if (cur->fault_handler(cur, regs, trapnr)) |
| return 1; |
| } |
| return 0; |
| } |
| |
| static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct kprobe *cur = __this_cpu_read(kprobe_instance); |
| int ret = 0; |
| |
| if (cur && cur->break_handler) { |
| if (cur->break_handler(cur, regs)) |
| ret = 1; |
| } |
| reset_kprobe_instance(); |
| return ret; |
| } |
| |
| /* Walks the list and increments nmissed count for multiprobe case */ |
| void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) |
| { |
| struct kprobe *kp; |
| if (!kprobe_aggrprobe(p)) { |
| p->nmissed++; |
| } else { |
| list_for_each_entry_rcu(kp, &p->list, list) |
| kp->nmissed++; |
| } |
| return; |
| } |
| |
| void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
| struct hlist_head *head) |
| { |
| struct kretprobe *rp = ri->rp; |
| |
| /* remove rp inst off the rprobe_inst_table */ |
| hlist_del(&ri->hlist); |
| INIT_HLIST_NODE(&ri->hlist); |
| if (likely(rp)) { |
| raw_spin_lock(&rp->lock); |
| hlist_add_head(&ri->hlist, &rp->free_instances); |
| raw_spin_unlock(&rp->lock); |
| } else |
| /* Unregistering */ |
| hlist_add_head(&ri->hlist, head); |
| } |
| |
| void __kprobes kretprobe_hash_lock(struct task_struct *tsk, |
| struct hlist_head **head, unsigned long *flags) |
| __acquires(hlist_lock) |
| { |
| unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
| raw_spinlock_t *hlist_lock; |
| |
| *head = &kretprobe_inst_table[hash]; |
| hlist_lock = kretprobe_table_lock_ptr(hash); |
| raw_spin_lock_irqsave(hlist_lock, *flags); |
| } |
| |
| static void __kprobes kretprobe_table_lock(unsigned long hash, |
| unsigned long *flags) |
| __acquires(hlist_lock) |
| { |
| raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
| raw_spin_lock_irqsave(hlist_lock, *flags); |
| } |
| |
| void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, |
| unsigned long *flags) |
| __releases(hlist_lock) |
| { |
| unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
| raw_spinlock_t *hlist_lock; |
| |
| hlist_lock = kretprobe_table_lock_ptr(hash); |
| raw_spin_unlock_irqrestore(hlist_lock, *flags); |
| } |
| |
| static void __kprobes kretprobe_table_unlock(unsigned long hash, |
| unsigned long *flags) |
| __releases(hlist_lock) |
| { |
| raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
| raw_spin_unlock_irqrestore(hlist_lock, *flags); |
| } |
| |
| /* |
| * This function is called from finish_task_switch when task tk becomes dead, |
| * 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 __kprobes kprobe_flush_task(struct task_struct *tk) |
| { |
| struct kretprobe_instance *ri; |
| struct hlist_head *head, empty_rp; |
| struct hlist_node *node, *tmp; |
| unsigned long hash, flags = 0; |
| |
| if (unlikely(!kprobes_initialized)) |
| /* Early boot. kretprobe_table_locks not yet initialized. */ |
| return; |
| |
| hash = hash_ptr(tk, KPROBE_HASH_BITS); |
| head = &kretprobe_inst_table[hash]; |
| kretprobe_table_lock(hash, &flags); |
| hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
| if (ri->task == tk) |
| recycle_rp_inst(ri, &empty_rp); |
| } |
| kretprobe_table_unlock(hash, &flags); |
| INIT_HLIST_HEAD(&empty_rp); |
| hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
| hlist_del(&ri->hlist); |
| kfree(ri); |
| } |
| } |
| |
| static inline void free_rp_inst(struct kretprobe *rp) |
| { |
| struct kretprobe_instance *ri; |
| struct hlist_node *pos, *next; |
| |
| hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
| hlist_del(&ri->hlist); |
| kfree(ri); |
| } |
| } |
| |
| static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
| { |
| unsigned long flags, hash; |
| struct kretprobe_instance *ri; |
| struct hlist_node *pos, *next; |
| struct hlist_head *head; |
| |
| /* No race here */ |
| for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
| kretprobe_table_lock(hash, &flags); |
| head = &kretprobe_inst_table[hash]; |
| hlist_for_each_entry_safe(ri, pos, next, head, hlist) { |
| if (ri->rp == rp) |
| ri->rp = NULL; |
| } |
| kretprobe_table_unlock(hash, &flags); |
| } |
| free_rp_inst(rp); |
| } |
| |
| /* |
| * Add the new probe to ap->list. Fail if this is the |
| * second jprobe at the address - two jprobes can't coexist |
| */ |
| static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
| { |
| BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
| |
| if (p->break_handler || p->post_handler) |
| unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
| |
| if (p->break_handler) { |
| if (ap->break_handler) |
| return -EEXIST; |
| list_add_tail_rcu(&p->list, &ap->list); |
| ap->break_handler = aggr_break_handler; |
| } else |
| list_add_rcu(&p->list, &ap->list); |
| if (p->post_handler && !ap->post_handler) |
| ap->post_handler = aggr_post_handler; |
| |
| if (kprobe_disabled(ap) && !kprobe_disabled(p)) { |
| ap->flags &= ~KPROBE_FLAG_DISABLED; |
| if (!kprobes_all_disarmed) |
| /* Arm the breakpoint again. */ |
| __arm_kprobe(ap); |
| } |
| return 0; |
| } |
| |
| /* |
| * Fill in the required fields of the "manager kprobe". Replace the |
| * earlier kprobe in the hlist with the manager kprobe |
| */ |
| static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
| { |
| /* Copy p's insn slot to ap */ |
| copy_kprobe(p, ap); |
| flush_insn_slot(ap); |
| ap->addr = p->addr; |
| ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
| ap->pre_handler = aggr_pre_handler; |
| ap->fault_handler = aggr_fault_handler; |
| /* We don't care the kprobe which has gone. */ |
| if (p->post_handler && !kprobe_gone(p)) |
| ap->post_handler = aggr_post_handler; |
| if (p->break_handler && !kprobe_gone(p)) |
| ap->break_handler = aggr_break_handler; |
| |
| INIT_LIST_HEAD(&ap->list); |
| INIT_HLIST_NODE(&ap->hlist); |
| |
| list_add_rcu(&p->list, &ap->list); |
| hlist_replace_rcu(&p->hlist, &ap->hlist); |
| } |
| |
| /* |
| * This is the second or subsequent kprobe at the address - handle |
| * the intricacies |
| */ |
| static int __kprobes register_aggr_kprobe(struct kprobe *orig_p, |
| struct kprobe *p) |
| { |
| int ret = 0; |
| struct kprobe *ap = orig_p; |
| |
| if (!kprobe_aggrprobe(orig_p)) { |
| /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ |
| ap = alloc_aggr_kprobe(orig_p); |
| if (!ap) |
| return -ENOMEM; |
| init_aggr_kprobe(ap, orig_p); |
| } else if (kprobe_unused(ap)) |
| /* This probe is going to die. Rescue it */ |
| reuse_unused_kprobe(ap); |
| |
| if (kprobe_gone(ap)) { |
| /* |
| * Attempting to insert new probe at the same location that |
| * had a probe in the module vaddr area which already |
| * freed. So, the instruction slot has already been |
| * released. We need a new slot for the new probe. |
| */ |
| ret = arch_prepare_kprobe(ap); |
| if (ret) |
| /* |
| * Even if fail to allocate new slot, don't need to |
| * free aggr_probe. It will be used next time, or |
| * freed by unregister_kprobe. |
| */ |
| return ret; |
| |
| /* Prepare optimized instructions if possible. */ |
| prepare_optimized_kprobe(ap); |
| |
| /* |
| * Clear gone flag to prevent allocating new slot again, and |
| * set disabled flag because it is not armed yet. |
| */ |
| ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
| | KPROBE_FLAG_DISABLED; |
| } |
| |
| /* Copy ap's insn slot to p */ |
| copy_kprobe(ap, p); |
| return add_new_kprobe(ap, p); |
| } |
| |
| static int __kprobes in_kprobes_functions(unsigned long addr) |
| { |
| struct kprobe_blackpoint *kb; |
| |
| if (addr >= (unsigned long)__kprobes_text_start && |
| addr < (unsigned long)__kprobes_text_end) |
| return -EINVAL; |
| /* |
| * If there exists a kprobe_blacklist, verify and |
| * fail any probe registration in the prohibited area |
| */ |
| for (kb = kprobe_blacklist; kb->name != NULL; kb++) { |
| if (kb->start_addr) { |
| if (addr >= kb->start_addr && |
| addr < (kb->start_addr + kb->range)) |
| return -EINVAL; |
| } |
| } |
| return 0; |
| } |
| |
| /* |
| * If we have a symbol_name argument, look it up and add the offset field |
| * to it. This way, we can specify a relative address to a symbol. |
| * This returns encoded errors if it fails to look up symbol or invalid |
| * combination of parameters. |
| */ |
| static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) |
| { |
| kprobe_opcode_t *addr = p->addr; |
| |
| if ((p->symbol_name && p->addr) || |
| (!p->symbol_name && !p->addr)) |
| goto invalid; |
| |
| if (p->symbol_name) { |
| kprobe_lookup_name(p->symbol_name, addr); |
| if (!addr) |
| return ERR_PTR(-ENOENT); |
| } |
| |
| addr = (kprobe_opcode_t *)(((char *)addr) + p->offset); |
| if (addr) |
| return addr; |
| |
| invalid: |
| return ERR_PTR(-EINVAL); |
| } |
| |
| /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
| static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) |
| { |
| struct kprobe *ap, *list_p; |
| |
| ap = get_kprobe(p->addr); |
| if (unlikely(!ap)) |
| return NULL; |
| |
| if (p != ap) { |
| list_for_each_entry_rcu(list_p, &ap->list, list) |
| if (list_p == p) |
| /* kprobe p is a valid probe */ |
| goto valid; |
| return NULL; |
| } |
| valid: |
| return ap; |
| } |
| |
| /* Return error if the kprobe is being re-registered */ |
| static inline int check_kprobe_rereg(struct kprobe *p) |
| { |
| int ret = 0; |
| |
| mutex_lock(&kprobe_mutex); |
| if (__get_valid_kprobe(p)) |
| ret = -EINVAL; |
| mutex_unlock(&kprobe_mutex); |
| |
| return ret; |
| } |
| |
| int __kprobes register_kprobe(struct kprobe *p) |
| { |
| int ret = 0; |
| struct kprobe *old_p; |
| struct module *probed_mod; |
| kprobe_opcode_t *addr; |
| |
| addr = kprobe_addr(p); |
| if (IS_ERR(addr)) |
| return PTR_ERR(addr); |
| p->addr = addr; |
| |
| ret = check_kprobe_rereg(p); |
| if (ret) |
| return ret; |
| |
| jump_label_lock(); |
| preempt_disable(); |
| if (!kernel_text_address((unsigned long) p->addr) || |
| in_kprobes_functions((unsigned long) p->addr) || |
| ftrace_text_reserved(p->addr, p->addr) || |
| jump_label_text_reserved(p->addr, p->addr)) |
| goto fail_with_jump_label; |
| |
| /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ |
| p->flags &= KPROBE_FLAG_DISABLED; |
| |
| /* |
| * Check if are we probing a module. |
| */ |
| probed_mod = __module_text_address((unsigned long) p->addr); |
| if (probed_mod) { |
| /* Return -ENOENT if fail. */ |
| ret = -ENOENT; |
| /* |
| * We must hold a refcount of the probed module while updating |
| * its code to prohibit unexpected unloading. |
| */ |
| if (unlikely(!try_module_get(probed_mod))) |
| goto fail_with_jump_label; |
| |
| /* |
| * If the module freed .init.text, we couldn't insert |
| * kprobes in there. |
| */ |
| if (within_module_init((unsigned long)p->addr, probed_mod) && |
| probed_mod->state != MODULE_STATE_COMING) { |
| module_put(probed_mod); |
| goto fail_with_jump_label; |
| } |
| /* ret will be updated by following code */ |
| } |
| preempt_enable(); |
| jump_label_unlock(); |
| |
| p->nmissed = 0; |
| INIT_LIST_HEAD(&p->list); |
| mutex_lock(&kprobe_mutex); |
| |
| jump_label_lock(); /* needed to call jump_label_text_reserved() */ |
| |
| get_online_cpus(); /* For avoiding text_mutex deadlock. */ |
| mutex_lock(&text_mutex); |
| |
| old_p = get_kprobe(p->addr); |
| if (old_p) { |
| /* Since this may unoptimize old_p, locking text_mutex. */ |
| ret = register_aggr_kprobe(old_p, p); |
| goto out; |
| } |
| |
| ret = arch_prepare_kprobe(p); |
| if (ret) |
| goto out; |
| |
| INIT_HLIST_NODE(&p->hlist); |
| hlist_add_head_rcu(&p->hlist, |
| &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
| |
| if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
| __arm_kprobe(p); |
| |
| /* Try to optimize kprobe */ |
| try_to_optimize_kprobe(p); |
| |
| out: |
| mutex_unlock(&text_mutex); |
| put_online_cpus(); |
| jump_label_unlock(); |
| mutex_unlock(&kprobe_mutex); |
| |
| if (probed_mod) |
| module_put(probed_mod); |
| |
| return ret; |
| |
| fail_with_jump_label: |
| preempt_enable(); |
| jump_label_unlock(); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(register_kprobe); |
| |
| /* Check if all probes on the aggrprobe are disabled */ |
| static int __kprobes aggr_kprobe_disabled(struct kprobe *ap) |
| { |
| struct kprobe *kp; |
| |
| list_for_each_entry_rcu(kp, &ap->list, list) |
| if (!kprobe_disabled(kp)) |
| /* |
| * There is an active probe on the list. |
| * We can't disable this ap. |
| */ |
| return 0; |
| |
| return 1; |
| } |
| |
| /* Disable one kprobe: Make sure called under kprobe_mutex is locked */ |
| static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p) |
| { |
| struct kprobe *orig_p; |
| |
| /* Get an original kprobe for return */ |
| orig_p = __get_valid_kprobe(p); |
| if (unlikely(orig_p == NULL)) |
| return NULL; |
| |
| if (!kprobe_disabled(p)) { |
| /* Disable probe if it is a child probe */ |
| if (p != orig_p) |
| p->flags |= KPROBE_FLAG_DISABLED; |
| |
| /* Try to disarm and disable this/parent probe */ |
| if (p == orig_p || aggr_kprobe_disabled(orig_p)) { |
| disarm_kprobe(orig_p); |
| orig_p->flags |= KPROBE_FLAG_DISABLED; |
| } |
| } |
| |
| return orig_p; |
| } |
| |
| /* |
| * Unregister a kprobe without a scheduler synchronization. |
| */ |
| static int __kprobes __unregister_kprobe_top(struct kprobe *p) |
| { |
| struct kprobe *ap, *list_p; |
| |
| /* Disable kprobe. This will disarm it if needed. */ |
| ap = __disable_kprobe(p); |
| if (ap == NULL) |
| return -EINVAL; |
| |
| if (ap == p) |
| /* |
| * This probe is an independent(and non-optimized) kprobe |
| * (not an aggrprobe). Remove from the hash list. |
| */ |
| goto disarmed; |
| |
| /* Following process expects this probe is an aggrprobe */ |
| WARN_ON(!kprobe_aggrprobe(ap)); |
| |
| if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
| /* |
| * !disarmed could be happen if the probe is under delayed |
| * unoptimizing. |
| */ |
| goto disarmed; |
| else { |
| /* If disabling probe has special handlers, update aggrprobe */ |
| if (p->break_handler && !kprobe_gone(p)) |
| ap->break_handler = NULL; |
| if (p->post_handler && !kprobe_gone(p)) { |
| list_for_each_entry_rcu(list_p, &ap->list, list) { |
| if ((list_p != p) && (list_p->post_handler)) |
| goto noclean; |
| } |
| ap->post_handler = NULL; |
| } |
| noclean: |
| /* |
| * Remove from the aggrprobe: this path will do nothing in |
| * __unregister_kprobe_bottom(). |
| */ |
| list_del_rcu(&p->list); |
| if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
| /* |
| * Try to optimize this probe again, because post |
| * handler may have been changed. |
| */ |
| optimize_kprobe(ap); |
| } |
| return 0; |
| |
| disarmed: |
| BUG_ON(!kprobe_disarmed(ap)); |
| hlist_del_rcu(&ap->hlist); |
| return 0; |
| } |
| |
| static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
| { |
| struct kprobe *ap; |
| |
| if (list_empty(&p->list)) |
| /* This is an independent kprobe */ |
| arch_remove_kprobe(p); |
| else if (list_is_singular(&p->list)) { |
| /* This is the last child of an aggrprobe */ |
| ap = list_entry(p->list.next, struct kprobe, list); |
| list_del(&p->list); |
| free_aggr_kprobe(ap); |
| } |
| /* Otherwise, do nothing. */ |
| } |
| |
| int __kprobes register_kprobes(struct kprobe **kps, int num) |
| { |
| int i, ret = 0; |
| |
| if (num <= 0) |
| return -EINVAL; |
| for (i = 0; i < num; i++) { |
| ret = register_kprobe(kps[i]); |
| if (ret < 0) { |
| if (i > 0) |
| unregister_kprobes(kps, i); |
| break; |
| } |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(register_kprobes); |
| |
| void __kprobes unregister_kprobe(struct kprobe *p) |
| { |
| unregister_kprobes(&p, 1); |
| } |
| EXPORT_SYMBOL_GPL(unregister_kprobe); |
| |
| void __kprobes unregister_kprobes(struct kprobe **kps, int num) |
| { |
| int i; |
| |
| if (num <= 0) |
| return; |
| mutex_lock(&kprobe_mutex); |
| for (i = 0; i < num; i++) |
| if (__unregister_kprobe_top(kps[i]) < 0) |
| kps[i]->addr = NULL; |
| mutex_unlock(&kprobe_mutex); |
| |
| synchronize_sched(); |
| for (i = 0; i < num; i++) |
| if (kps[i]->addr) |
| __unregister_kprobe_bottom(kps[i]); |
| } |
| EXPORT_SYMBOL_GPL(unregister_kprobes); |
| |
| static struct notifier_block kprobe_exceptions_nb = { |
| .notifier_call = kprobe_exceptions_notify, |
| .priority = 0x7fffffff /* we need to be notified first */ |
| }; |
| |
| unsigned long __weak arch_deref_entry_point(void *entry) |
| { |
| return (unsigned long)entry; |
| } |
| |
| int __kprobes register_jprobes(struct jprobe **jps, int num) |
| { |
| struct jprobe *jp; |
| int ret = 0, i; |
| |
| if (num <= 0) |
| return -EINVAL; |
| for (i = 0; i < num; i++) { |
| unsigned long addr, offset; |
| jp = jps[i]; |
| addr = arch_deref_entry_point(jp->entry); |
| |
| /* Verify probepoint is a function entry point */ |
| if (kallsyms_lookup_size_offset(addr, NULL, &offset) && |
| offset == 0) { |
| jp->kp.pre_handler = setjmp_pre_handler; |
| jp->kp.break_handler = longjmp_break_handler; |
| ret = register_kprobe(&jp->kp); |
| } else |
| ret = -EINVAL; |
| |
| if (ret < 0) { |
| if (i > 0) |
| unregister_jprobes(jps, i); |
| break; |
| } |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(register_jprobes); |
| |
| int __kprobes register_jprobe(struct jprobe *jp) |
| { |
| return register_jprobes(&jp, 1); |
| } |
| EXPORT_SYMBOL_GPL(register_jprobe); |
| |
| void __kprobes unregister_jprobe(struct jprobe *jp) |
| { |
| unregister_jprobes(&jp, 1); |
| } |
| EXPORT_SYMBOL_GPL(unregister_jprobe); |
| |
| void __kprobes unregister_jprobes(struct jprobe **jps, int num) |
| { |
| int i; |
| |
| if (num <= 0) |
| return; |
| mutex_lock(&kprobe_mutex); |
| for (i = 0; i < num; i++) |
| if (__unregister_kprobe_top(&jps[i]->kp) < 0) |
| jps[i]->kp.addr = NULL; |
| mutex_unlock(&kprobe_mutex); |
| |
| synchronize_sched(); |
| for (i = 0; i < num; i++) { |
| if (jps[i]->kp.addr) |
| __unregister_kprobe_bottom(&jps[i]->kp); |
| } |
| } |
| EXPORT_SYMBOL_GPL(unregister_jprobes); |
| |
| #ifdef CONFIG_KRETPROBES |
| /* |
| * This kprobe pre_handler is registered with every kretprobe. When probe |
| * hits it will set up the return probe. |
| */ |
| static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
| struct pt_regs *regs) |
| { |
| struct kretprobe *rp = container_of(p, struct kretprobe, kp); |
| unsigned long hash, flags = 0; |
| struct kretprobe_instance *ri; |
| |
| /*TODO: consider to only swap the RA after the last pre_handler fired */ |
| hash = hash_ptr(current, KPROBE_HASH_BITS); |
| raw_spin_lock_irqsave(&rp->lock, flags); |
| if (!hlist_empty(&rp->free_instances)) { |
| ri = hlist_entry(rp->free_instances.first, |
| struct kretprobe_instance, hlist); |
| hlist_del(&ri->hlist); |
| raw_spin_unlock_irqrestore(&rp->lock, flags); |
| |
| ri->rp = rp; |
| ri->task = current; |
| |
| if (rp->entry_handler && rp->entry_handler(ri, regs)) |
| return 0; |
| |
| arch_prepare_kretprobe(ri, regs); |
| |
| /* XXX(hch): why is there no hlist_move_head? */ |
| INIT_HLIST_NODE(&ri->hlist); |
| kretprobe_table_lock(hash, &flags); |
| hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); |
| kretprobe_table_unlock(hash, &flags); |
| } else { |
| rp->nmissed++; |
| raw_spin_unlock_irqrestore(&rp->lock, flags); |
| } |
| return 0; |
| } |
| |
| int __kprobes register_kretprobe(struct kretprobe *rp) |
| { |
| int ret = 0; |
| struct kretprobe_instance *inst; |
| int i; |
| void *addr; |
| |
| if (kretprobe_blacklist_size) { |
| addr = kprobe_addr(&rp->kp); |
| if (IS_ERR(addr)) |
| return PTR_ERR(addr); |
| |
| 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; |
| rp->kp.fault_handler = NULL; |
| rp->kp.break_handler = NULL; |
| |
| /* Pre-allocate memory for max kretprobe instances */ |
| if (rp->maxactive <= 0) { |
| #ifdef CONFIG_PREEMPT |
| rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
| #else |
| rp->maxactive = num_possible_cpus(); |
| #endif |
| } |
| raw_spin_lock_init(&rp->lock); |
| INIT_HLIST_HEAD(&rp->free_instances); |
| for (i = 0; i < rp->maxactive; i++) { |
| inst = kmalloc(sizeof(struct kretprobe_instance) + |
| rp->data_size, GFP_KERNEL); |
| if (inst == NULL) { |
| free_rp_inst(rp); |
| return -ENOMEM; |
| } |
| INIT_HLIST_NODE(&inst->hlist); |
| hlist_add_head(&inst->hlist, &rp->free_instances); |
| } |
| |
| rp->nmissed = 0; |
| /* Establish function entry probe point */ |
| ret = register_kprobe(&rp->kp); |
| if (ret != 0) |
| free_rp_inst(rp); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(register_kretprobe); |
| |
| int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
| { |
| int ret = 0, i; |
| |
| if (num <= 0) |
| return -EINVAL; |
| for (i = 0; i < num; i++) { |
| ret = register_kretprobe(rps[i]); |
| if (ret < 0) { |
| if (i > 0) |
| unregister_kretprobes(rps, i); |
| break; |
| } |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(register_kretprobes); |
| |
| void __kprobes unregister_kretprobe(struct kretprobe *rp) |
| { |
| unregister_kretprobes(&rp, 1); |
| } |
| EXPORT_SYMBOL_GPL(unregister_kretprobe); |
| |
| 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]); |
| } |
| } |
| } |
| EXPORT_SYMBOL_GPL(unregister_kretprobes); |
| |
| #else /* CONFIG_KRETPROBES */ |
| int __kprobes register_kretprobe(struct kretprobe *rp) |
| { |
| return -ENOSYS; |
| } |
| EXPORT_SYMBOL_GPL(register_kretprobe); |
| |
| int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
| { |
| return -ENOSYS; |
| } |
| EXPORT_SYMBOL_GPL(register_kretprobes); |
| |
| void __kprobes unregister_kretprobe(struct kretprobe *rp) |
| { |
| } |
| EXPORT_SYMBOL_GPL(unregister_kretprobe); |
| |
| void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
| { |
| } |
| EXPORT_SYMBOL_GPL(unregister_kretprobes); |
| |
| static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
| struct pt_regs *regs) |
| { |
| return 0; |
| } |
| |
| #endif /* CONFIG_KRETPROBES */ |
| |
| /* Set the kprobe gone and remove its instruction buffer. */ |
| static void __kprobes kill_kprobe(struct kprobe *p) |
| { |
| struct kprobe *kp; |
| |
| p->flags |= KPROBE_FLAG_GONE; |
| if (kprobe_aggrprobe(p)) { |
| /* |
| * If this is an aggr_kprobe, we have to list all the |
| * chained probes and mark them GONE. |
| */ |
| list_for_each_entry_rcu(kp, &p->list, list) |
| kp->flags |= KPROBE_FLAG_GONE; |
| p->post_handler = NULL; |
| p->break_handler = NULL; |
| kill_optimized_kprobe(p); |
| } |
| /* |
| * Here, we can remove insn_slot safely, because no thread calls |
| * the original probed function (which will be freed soon) any more. |
| */ |
| arch_remove_kprobe(p); |
| } |
| |
| /* Disable one kprobe */ |
| int __kprobes disable_kprobe(struct kprobe *kp) |
| { |
| int ret = 0; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| /* Disable this kprobe */ |
| if (__disable_kprobe(kp) == NULL) |
| ret = -EINVAL; |
| |
| mutex_unlock(&kprobe_mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(disable_kprobe); |
| |
| /* Enable one kprobe */ |
| int __kprobes enable_kprobe(struct kprobe *kp) |
| { |
| int ret = 0; |
| struct kprobe *p; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| /* Check whether specified probe is valid. */ |
| p = __get_valid_kprobe(kp); |
| if (unlikely(p == NULL)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (kprobe_gone(kp)) { |
| /* This kprobe has gone, we couldn't enable it. */ |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (p != kp) |
| kp->flags &= ~KPROBE_FLAG_DISABLED; |
| |
| if (!kprobes_all_disarmed && kprobe_disabled(p)) { |
| p->flags &= ~KPROBE_FLAG_DISABLED; |
| arm_kprobe(p); |
| } |
| out: |
| mutex_unlock(&kprobe_mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(enable_kprobe); |
| |
| void __kprobes dump_kprobe(struct kprobe *kp) |
| { |
| printk(KERN_WARNING "Dumping kprobe:\n"); |
| printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", |
| kp->symbol_name, kp->addr, kp->offset); |
| } |
| |
| /* Module notifier call back, checking kprobes on the module */ |
| static int __kprobes kprobes_module_callback(struct notifier_block *nb, |
| unsigned long val, void *data) |
| { |
| struct module *mod = data; |
| struct hlist_head *head; |
| struct hlist_node *node; |
| struct kprobe *p; |
| unsigned int i; |
| int checkcore = (val == MODULE_STATE_GOING); |
| |
| if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
| return NOTIFY_DONE; |
| |
| /* |
| * When MODULE_STATE_GOING was notified, both of module .text and |
| * .init.text sections would be freed. When MODULE_STATE_LIVE was |
| * notified, only .init.text section would be freed. We need to |
| * disable kprobes which have been inserted in the sections. |
| */ |
| mutex_lock(&kprobe_mutex); |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| hlist_for_each_entry_rcu(p, node, head, hlist) |
| if (within_module_init((unsigned long)p->addr, mod) || |
| (checkcore && |
| within_module_core((unsigned long)p->addr, mod))) { |
| /* |
| * The vaddr this probe is installed will soon |
| * be vfreed buy not synced to disk. Hence, |
| * disarming the breakpoint isn't needed. |
| */ |
| kill_kprobe(p); |
| } |
| } |
| mutex_unlock(&kprobe_mutex); |
| return NOTIFY_DONE; |
| } |
| |
| static struct notifier_block kprobe_module_nb = { |
| .notifier_call = kprobes_module_callback, |
| .priority = 0 |
| }; |
| |
| static int __init init_kprobes(void) |
| { |
| int i, err = 0; |
| unsigned long offset = 0, size = 0; |
| char *modname, namebuf[128]; |
| const char *symbol_name; |
| void *addr; |
| struct kprobe_blackpoint *kb; |
| |
| /* FIXME allocate the probe table, currently defined statically */ |
| /* initialize all list heads */ |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| INIT_HLIST_HEAD(&kprobe_table[i]); |
| INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
| raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); |
| } |
| |
| /* |
| * Lookup and populate the kprobe_blacklist. |
| * |
| * Unlike the kretprobe blacklist, we'll need to determine |
| * the range of addresses that belong to the said functions, |
| * since a kprobe need not necessarily be at the beginning |
| * of a function. |
| */ |
| for (kb = kprobe_blacklist; kb->name != NULL; kb++) { |
| kprobe_lookup_name(kb->name, addr); |
| if (!addr) |
| continue; |
| |
| kb->start_addr = (unsigned long)addr; |
| symbol_name = kallsyms_lookup(kb->start_addr, |
| &size, &offset, &modname, namebuf); |
| if (!symbol_name) |
| kb->range = 0; |
| else |
| kb->range = size; |
| } |
| |
| 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); |
| } |
| } |
| |
| #if defined(CONFIG_OPTPROBES) |
| #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) |
| /* Init kprobe_optinsn_slots */ |
| kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; |
| #endif |
| /* By default, kprobes can be optimized */ |
| kprobes_allow_optimization = true; |
| #endif |
| |
| /* By default, kprobes are armed */ |
| kprobes_all_disarmed = false; |
| |
| err = arch_init_kprobes(); |
| if (!err) |
| err = register_die_notifier(&kprobe_exceptions_nb); |
| if (!err) |
| err = register_module_notifier(&kprobe_module_nb); |
| |
| kprobes_initialized = (err == 0); |
| |
| if (!err) |
| init_test_probes(); |
| return err; |
| } |
| |
| #ifdef CONFIG_DEBUG_FS |
| static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, |
| const char *sym, int offset, char *modname, struct kprobe *pp) |
| { |
| char *kprobe_type; |
| |
| if (p->pre_handler == pre_handler_kretprobe) |
| kprobe_type = "r"; |
| else if (p->pre_handler == setjmp_pre_handler) |
| kprobe_type = "j"; |
| else |
| kprobe_type = "k"; |
| |
| if (sym) |
| seq_printf(pi, "%p %s %s+0x%x %s ", |
| p->addr, kprobe_type, sym, offset, |
| (modname ? modname : " ")); |
| else |
| seq_printf(pi, "%p %s %p ", |
| p->addr, kprobe_type, p->addr); |
| |
| if (!pp) |
| pp = p; |
| seq_printf(pi, "%s%s%s\n", |
| (kprobe_gone(p) ? "[GONE]" : ""), |
| ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), |
| (kprobe_optimized(pp) ? "[OPTIMIZED]" : "")); |
| } |
| |
| static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
| { |
| return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; |
| } |
| |
| static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
| { |
| (*pos)++; |
| if (*pos >= KPROBE_TABLE_SIZE) |
| return NULL; |
| return pos; |
| } |
| |
| static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) |
| { |
| /* Nothing to do */ |
| } |
| |
| static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) |
| { |
| struct hlist_head *head; |
| struct hlist_node *node; |
| struct kprobe *p, *kp; |
| const char *sym = NULL; |
| unsigned int i = *(loff_t *) v; |
| unsigned long offset = 0; |
| char *modname, namebuf[128]; |
| |
| head = &kprobe_table[i]; |
| preempt_disable(); |
| hlist_for_each_entry_rcu(p, node, head, hlist) { |
| sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
| &offset, &modname, namebuf); |
| if (kprobe_aggrprobe(p)) { |
| list_for_each_entry_rcu(kp, &p->list, list) |
| report_probe(pi, kp, sym, offset, modname, p); |
| } else |
| report_probe(pi, p, sym, offset, modname, NULL); |
| } |
| preempt_enable(); |
| return 0; |
| } |
| |
| static const struct seq_operations kprobes_seq_ops = { |
| .start = kprobe_seq_start, |
| .next = kprobe_seq_next, |
| .stop = kprobe_seq_stop, |
| .show = show_kprobe_addr |
| }; |
| |
| static int __kprobes kprobes_open(struct inode *inode, struct file *filp) |
| { |
| return seq_open(filp, &kprobes_seq_ops); |
| } |
| |
| static const struct file_operations debugfs_kprobes_operations = { |
| .open = kprobes_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release, |
| }; |
| |
| static void __kprobes arm_all_kprobes(void) |
| { |
| struct hlist_head *head; |
| struct hlist_node *node; |
| struct kprobe *p; |
| unsigned int i; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| /* If kprobes are armed, just return */ |
| if (!kprobes_all_disarmed) |
| goto already_enabled; |
| |
| /* Arming kprobes doesn't optimize kprobe itself */ |
| mutex_lock(&text_mutex); |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| hlist_for_each_entry_rcu(p, node, head, hlist) |
| if (!kprobe_disabled(p)) |
| __arm_kprobe(p); |
| } |
| mutex_unlock(&text_mutex); |
| |
| kprobes_all_disarmed = false; |
| printk(KERN_INFO "Kprobes globally enabled\n"); |
| |
| already_enabled: |
| mutex_unlock(&kprobe_mutex); |
| return; |
| } |
| |
| static void __kprobes disarm_all_kprobes(void) |
| { |
| struct hlist_head *head; |
| struct hlist_node *node; |
| struct kprobe *p; |
| unsigned int i; |
| |
| mutex_lock(&kprobe_mutex); |
| |
| /* If kprobes are already disarmed, just return */ |
| if (kprobes_all_disarmed) { |
| mutex_unlock(&kprobe_mutex); |
| return; |
| } |
| |
| kprobes_all_disarmed = true; |
| printk(KERN_INFO "Kprobes globally disabled\n"); |
| |
| mutex_lock(&text_mutex); |
| for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
| head = &kprobe_table[i]; |
| hlist_for_each_entry_rcu(p, node, head, hlist) { |
| if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
| __disarm_kprobe(p, false); |
| } |
| } |
| mutex_unlock(&text_mutex); |
| mutex_unlock(&kprobe_mutex); |
| |
| /* Wait for disarming all kprobes by optimizer */ |
| wait_for_kprobe_optimizer(); |
| } |
| |
| /* |
| * XXX: The debugfs bool file interface doesn't allow for callbacks |
| * when the bool state is switched. We can reuse that facility when |
| * available |
| */ |
| static ssize_t read_enabled_file_bool(struct file *file, |
| char __user *user_buf, size_t count, loff_t *ppos) |
| { |
| char buf[3]; |
| |
| if (!kprobes_all_disarmed) |
| buf[0] = '1'; |
| else |
| buf[0] = '0'; |
| buf[1] = '\n'; |
| buf[2] = 0x00; |
| return simple_read_from_buffer(user_buf, count, ppos, buf, 2); |
| } |
| |
| static ssize_t write_enabled_file_bool(struct file *file, |
| const char __user *user_buf, size_t count, loff_t *ppos) |
| { |
| char buf[32]; |
| size_t buf_size; |
| |
| buf_size = min(count, (sizeof(buf)-1)); |
| if (copy_from_user(buf, user_buf, buf_size)) |
| return -EFAULT; |
| |
| switch (buf[0]) { |
| case 'y': |
| case 'Y': |
| case '1': |
| arm_all_kprobes(); |
| break; |
| case 'n': |
| case 'N': |
| case '0': |
| disarm_all_kprobes(); |
| break; |
| } |
| |
| return count; |
| } |
| |
| static const struct file_operations fops_kp = { |
| .read = read_enabled_file_bool, |
| .write = write_enabled_file_bool, |
| .llseek = default_llseek, |
| }; |
| |
| static int __kprobes debugfs_kprobe_init(void) |
| { |
| struct dentry *dir, *file; |
| unsigned int value = 1; |
| |
| dir = debugfs_create_dir("kprobes", NULL); |
| if (!dir) |
| return -ENOMEM; |
| |
| file = debugfs_create_file("list", 0444, dir, NULL, |
| &debugfs_kprobes_operations); |
| if (!file) { |
| debugfs_remove(dir); |
| return -ENOMEM; |
| } |
| |
| file = debugfs_create_file("enabled", 0600, dir, |
| &value, &fops_kp); |
| if (!file) { |
| debugfs_remove(dir); |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| late_initcall(debugfs_kprobe_init); |
| #endif /* CONFIG_DEBUG_FS */ |
| |
| module_init(init_kprobes); |
| |
| /* defined in arch/.../kernel/kprobes.c */ |
| EXPORT_SYMBOL_GPL(jprobe_return); |