--- /dev/null
+/*
+ * 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);
+}
+
+/* Blacklist -- list of struct kprobe_blacklist_entry */
+static LIST_HEAD(kprobe_blacklist);
+
+#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 */
+ struct kprobe_insn_cache *cache;
+ int nused;
+ int ngarbage;
+ char slot_used[];
+};
+
+#define KPROBE_INSN_PAGE_SIZE(slots) \
+ (offsetof(struct kprobe_insn_page, slot_used) + \
+ (sizeof(char) * (slots)))
+
+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 void *alloc_insn_page(void)
+{
+ return module_alloc(PAGE_SIZE);
+}
+
+static void free_insn_page(void *page)
+{
+ module_memfree(page);
+}
+
+struct kprobe_insn_cache kprobe_insn_slots = {
+ .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
+ .alloc = alloc_insn_page,
+ .free = free_insn_page,
+ .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
+ .insn_size = MAX_INSN_SIZE,
+ .nr_garbage = 0,
+};
+static int 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.
+ */
+kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
+{
+ struct kprobe_insn_page *kip;
+ kprobe_opcode_t *slot = NULL;
+
+ mutex_lock(&c->mutex);
+ 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++;
+ slot = kip->insns + (i * c->insn_size);
+ goto out;
+ }
+ }
+ /* 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)
+ goto out;
+
+ /*
+ * 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 = c->alloc();
+ if (!kip->insns) {
+ kfree(kip);
+ goto out;
+ }
+ 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;
+ kip->cache = c;
+ list_add(&kip->list, &c->pages);
+ slot = kip->insns;
+out:
+ mutex_unlock(&c->mutex);
+ return slot;
+}
+
+/* Return 1 if all garbages are collected, otherwise 0. */
+static int 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);
+ kip->cache->free(kip->insns);
+ kfree(kip);
+ }
+ return 1;
+ }
+ return 0;
+}
+
+static int 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;
+}
+
+void __free_insn_slot(struct kprobe_insn_cache *c,
+ kprobe_opcode_t *slot, int dirty)
+{
+ struct kprobe_insn_page *kip;
+
+ mutex_lock(&c->mutex);
+ 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);
+ goto out;
+ }
+ }
+ /* Could not free this slot. */
+ WARN_ON(1);
+out:
+ mutex_unlock(&c->mutex);
+}
+
+#ifdef CONFIG_OPTPROBES
+/* For optimized_kprobe buffer */
+struct kprobe_insn_cache kprobe_optinsn_slots = {
+ .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
+ .alloc = alloc_insn_page,
+ .free = free_insn_page,
+ .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
+ /* .insn_size is initialized later */
+ .nr_garbage = 0,
+};
+#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 *get_kprobe(void *addr)
+{
+ struct hlist_head *head;
+ struct kprobe *p;
+
+ head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
+ hlist_for_each_entry_rcu(p, head, hlist) {
+ if (p->addr == addr)
+ return p;
+ }
+
+ return NULL;
+}
+NOKPROBE_SYMBOL(get_kprobe);
+
+static int 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 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();
+ }
+}
+NOKPROBE_SYMBOL(opt_pre_handler);
+
+/* Free optimized instructions and optimized_kprobe */
+static 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 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 *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 LIST_HEAD(freeing_list);
+
+static void kprobe_optimizer(struct work_struct *work);
+static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
+#define OPTIMIZE_DELAY 5
+
+/*
+ * Optimize (replace a breakpoint with a jump) kprobes listed on
+ * optimizing_list.
+ */
+static 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 void do_unoptimize_kprobes(void)
+{
+ 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, &freeing_list);
+ /* Loop free_list for disarming */
+ list_for_each_entry_safe(op, tmp, &freeing_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 void do_free_cleaned_kprobes(void)
+{
+ struct optimized_kprobe *op, *tmp;
+
+ list_for_each_entry_safe(op, tmp, &freeing_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 void kick_kprobe_optimizer(void)
+{
+ schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
+}
+
+/* Kprobe jump optimizer */
+static void kprobe_optimizer(struct work_struct *work)
+{
+ mutex_lock(&kprobe_mutex);
+ /* Lock modules while optimizing kprobes */
+ mutex_lock(&module_mutex);
+
+ /*
+ * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
+ * kprobes before waiting for quiesence period.
+ */
+ do_unoptimize_kprobes();
+
+ /*
+ * 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();
+
+ mutex_unlock(&module_mutex);
+ mutex_unlock(&kprobe_mutex);
+
+ /* Step 5: Kick optimizer again if needed */
+ if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
+ kick_kprobe_optimizer();
+}
+
+/* Wait for completing optimization and unoptimization */
+static void wait_for_kprobe_optimizer(void)
+{
+ mutex_lock(&kprobe_mutex);
+
+ while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) {
+ mutex_unlock(&kprobe_mutex);
+
+ /* this will also make optimizing_work execute immmediately */
+ flush_delayed_work(&optimizing_work);
+ /* @optimizing_work might not have been queued yet, relax */
+ cpu_relax();
+
+ mutex_lock(&kprobe_mutex);
+ }
+
+ mutex_unlock(&kprobe_mutex);
+}
+
+/* Optimize kprobe if p is ready to be optimized */
+static 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 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 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 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;
+
+ if (kprobe_unused(p)) {
+ /* Enqueue if it is unused */
+ list_add(&op->list, &freeing_list);
+ /*
+ * Remove unused probes from the hash list. After waiting
+ * for synchronization, this probe is reclaimed.
+ * (reclaiming is done by do_free_cleaned_kprobes().)
+ */
+ hlist_del_rcu(&op->kp.hlist);
+ }
+
+ /* Don't touch the code, because it is already freed. */
+ arch_remove_optimized_kprobe(op);
+}
+
+/* Try to prepare optimized instructions */
+static void prepare_optimized_kprobe(struct kprobe *p)
+{
+ struct optimized_kprobe *op;
+
+ op = container_of(p, struct optimized_kprobe, kp);
+ arch_prepare_optimized_kprobe(op, p);
+}
+
+/* Allocate new optimized_kprobe and try to prepare optimized instructions */
+static 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, p);
+
+ return &op->kp;
+}
+
+static void 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 void try_to_optimize_kprobe(struct kprobe *p)
+{
+ struct kprobe *ap;
+ struct optimized_kprobe *op;
+
+ /* Impossible to optimize ftrace-based kprobe */
+ if (kprobe_ftrace(p))
+ return;
+
+ /* For preparing optimization, jump_label_text_reserved() is called */
+ jump_label_lock();
+ mutex_lock(&text_mutex);
+
+ ap = alloc_aggr_kprobe(p);
+ if (!ap)
+ goto out;
+
+ 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);
+ goto out;
+ }
+
+ init_aggr_kprobe(ap, p);
+ optimize_kprobe(ap); /* This just kicks optimizer thread */
+
+out:
+ mutex_unlock(&text_mutex);
+ jump_label_unlock();
+}
+
+#ifdef CONFIG_SYSCTL
+static void optimize_all_kprobes(void)
+{
+ struct hlist_head *head;
+ struct kprobe *p;
+ unsigned int i;
+
+ mutex_lock(&kprobe_mutex);
+ /* If optimization is already allowed, just return */
+ if (kprobes_allow_optimization)
+ goto out;
+
+ kprobes_allow_optimization = true;
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry_rcu(p, head, hlist)
+ if (!kprobe_disabled(p))
+ optimize_kprobe(p);
+ }
+ printk(KERN_INFO "Kprobes globally optimized\n");
+out:
+ mutex_unlock(&kprobe_mutex);
+}
+
+static void unoptimize_all_kprobes(void)
+{
+ struct hlist_head *head;
+ struct kprobe *p;
+ unsigned int i;
+
+ mutex_lock(&kprobe_mutex);
+ /* If optimization is already prohibited, just return */
+ if (!kprobes_allow_optimization) {
+ mutex_unlock(&kprobe_mutex);
+ return;
+ }
+
+ kprobes_allow_optimization = false;
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry_rcu(p, head, hlist) {
+ if (!kprobe_disabled(p))
+ unoptimize_kprobe(p, false);
+ }
+ }
+ mutex_unlock(&kprobe_mutex);
+
+ /* Wait for unoptimizing completion */
+ wait_for_kprobe_optimizer();
+ printk(KERN_INFO "Kprobes globally unoptimized\n");
+}
+
+static DEFINE_MUTEX(kprobe_sysctl_mutex);
+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_sysctl_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_sysctl_mutex);
+
+ return ret;
+}
+#endif /* CONFIG_SYSCTL */
+
+/* Put a breakpoint for a probe. Must be called with text_mutex locked */
+static void __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 __disarm_kprobe(struct kprobe *p, bool reopt)
+{
+ struct kprobe *_p;
+
+ /* Try to unoptimize */
+ unoptimize_kprobe(p, kprobes_all_disarmed);
+
+ 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 void free_aggr_kprobe(struct kprobe *p)
+{
+ arch_remove_kprobe(p);
+ kfree(p);
+}
+
+static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
+{
+ return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
+}
+#endif /* CONFIG_OPTPROBES */
+
+#ifdef CONFIG_KPROBES_ON_FTRACE
+static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
+ .func = kprobe_ftrace_handler,
+ .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
+};
+static int kprobe_ftrace_enabled;
+
+/* Must ensure p->addr is really on ftrace */
+static int prepare_kprobe(struct kprobe *p)
+{
+ if (!kprobe_ftrace(p))
+ return arch_prepare_kprobe(p);
+
+ return arch_prepare_kprobe_ftrace(p);
+}
+
+/* Caller must lock kprobe_mutex */
+static void arm_kprobe_ftrace(struct kprobe *p)
+{
+ int ret;
+
+ ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
+ (unsigned long)p->addr, 0, 0);
+ WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret);
+ kprobe_ftrace_enabled++;
+ if (kprobe_ftrace_enabled == 1) {
+ ret = register_ftrace_function(&kprobe_ftrace_ops);
+ WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
+ }
+}
+
+/* Caller must lock kprobe_mutex */
+static void disarm_kprobe_ftrace(struct kprobe *p)
+{
+ int ret;
+
+ kprobe_ftrace_enabled--;
+ if (kprobe_ftrace_enabled == 0) {
+ ret = unregister_ftrace_function(&kprobe_ftrace_ops);
+ WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
+ }
+ ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
+ (unsigned long)p->addr, 1, 0);
+ WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
+}
+#else /* !CONFIG_KPROBES_ON_FTRACE */
+#define prepare_kprobe(p) arch_prepare_kprobe(p)
+#define arm_kprobe_ftrace(p) do {} while (0)
+#define disarm_kprobe_ftrace(p) do {} while (0)
+#endif
+
+/* Arm a kprobe with text_mutex */
+static void arm_kprobe(struct kprobe *kp)
+{
+ if (unlikely(kprobe_ftrace(kp))) {
+ arm_kprobe_ftrace(kp);
+ return;
+ }
+ /*
+ * 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 disarm_kprobe(struct kprobe *kp, bool reopt)
+{
+ if (unlikely(kprobe_ftrace(kp))) {
+ disarm_kprobe_ftrace(kp);
+ return;
+ }
+ /* Ditto */
+ mutex_lock(&text_mutex);
+ __disarm_kprobe(kp, reopt);
+ 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 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;
+}
+NOKPROBE_SYMBOL(aggr_pre_handler);
+
+static void 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();
+ }
+ }
+}
+NOKPROBE_SYMBOL(aggr_post_handler);
+
+static int 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;
+}
+NOKPROBE_SYMBOL(aggr_fault_handler);
+
+static int 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;
+}
+NOKPROBE_SYMBOL(aggr_break_handler);
+
+/* Walks the list and increments nmissed count for multiprobe case */
+void 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;
+}
+NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
+
+void 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);
+}
+NOKPROBE_SYMBOL(recycle_rp_inst);
+
+void 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);
+}
+NOKPROBE_SYMBOL(kretprobe_hash_lock);
+
+static void 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);
+}
+NOKPROBE_SYMBOL(kretprobe_table_lock);
+
+void 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);
+}
+NOKPROBE_SYMBOL(kretprobe_hash_unlock);
+
+static void 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);
+}
+NOKPROBE_SYMBOL(kretprobe_table_unlock);
+
+/*
+ * 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 kprobe_flush_task(struct task_struct *tk)
+{
+ struct kretprobe_instance *ri;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *tmp;
+ unsigned long hash, flags = 0;
+
+ if (unlikely(!kprobes_initialized))
+ /* Early boot. kretprobe_table_locks not yet initialized. */
+ return;
+
+ INIT_HLIST_HEAD(&empty_rp);
+ hash = hash_ptr(tk, KPROBE_HASH_BITS);
+ head = &kretprobe_inst_table[hash];
+ kretprobe_table_lock(hash, &flags);
+ hlist_for_each_entry_safe(ri, tmp, head, hlist) {
+ if (ri->task == tk)
+ recycle_rp_inst(ri, &empty_rp);
+ }
+ kretprobe_table_unlock(hash, &flags);
+ hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+}
+NOKPROBE_SYMBOL(kprobe_flush_task);
+
+static inline void free_rp_inst(struct kretprobe *rp)
+{
+ struct kretprobe_instance *ri;
+ struct hlist_node *next;
+
+ hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+}
+
+static void cleanup_rp_inst(struct kretprobe *rp)
+{
+ unsigned long flags, hash;
+ struct kretprobe_instance *ri;
+ struct hlist_node *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, next, head, hlist) {
+ if (ri->rp == rp)
+ ri->rp = NULL;
+ }
+ kretprobe_table_unlock(hash, &flags);
+ }
+ free_rp_inst(rp);
+}
+NOKPROBE_SYMBOL(cleanup_rp_inst);
+
+/*
+* Add the new probe to ap->list. Fail if this is the
+* second jprobe at the address - two jprobes can't coexist
+*/
+static int 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;
+
+ return 0;
+}
+
+/*
+ * Fill in the required fields of the "manager kprobe". Replace the
+ * earlier kprobe in the hlist with the manager kprobe
+ */
+static void 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 register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
+{
+ int ret = 0;
+ struct kprobe *ap = orig_p;
+
+ /* For preparing optimization, jump_label_text_reserved() is called */
+ jump_label_lock();
+ /*
+ * Get online CPUs to avoid text_mutex deadlock.with stop machine,
+ * which is invoked by unoptimize_kprobe() in add_new_kprobe()
+ */
+ get_online_cpus();
+ mutex_lock(&text_mutex);
+
+ 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) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ 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.
+ */
+ goto out;
+
+ /* 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);
+ ret = add_new_kprobe(ap, p);
+
+out:
+ mutex_unlock(&text_mutex);
+ put_online_cpus();
+ jump_label_unlock();
+
+ if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
+ ap->flags &= ~KPROBE_FLAG_DISABLED;
+ if (!kprobes_all_disarmed)
+ /* Arm the breakpoint again. */
+ arm_kprobe(ap);
+ }
+ return ret;
+}
+
+bool __weak arch_within_kprobe_blacklist(unsigned long addr)
+{
+ /* The __kprobes marked functions and entry code must not be probed */
+ return addr >= (unsigned long)__kprobes_text_start &&
+ addr < (unsigned long)__kprobes_text_end;
+}
+
+static bool within_kprobe_blacklist(unsigned long addr)
+{
+ struct kprobe_blacklist_entry *ent;
+
+ if (arch_within_kprobe_blacklist(addr))
+ return true;
+ /*
+ * If there exists a kprobe_blacklist, verify and
+ * fail any probe registration in the prohibited area
+ */
+ list_for_each_entry(ent, &kprobe_blacklist, list) {
+ if (addr >= ent->start_addr && addr < ent->end_addr)
+ return true;
+ }
+
+ return false;
+}
+
+/*
+ * 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 *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 *__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 __weak arch_check_ftrace_location(struct kprobe *p)
+{
+ unsigned long ftrace_addr;
+
+ ftrace_addr = ftrace_location((unsigned long)p->addr);
+ if (ftrace_addr) {
+#ifdef CONFIG_KPROBES_ON_FTRACE
+ /* Given address is not on the instruction boundary */
+ if ((unsigned long)p->addr != ftrace_addr)
+ return -EILSEQ;
+ p->flags |= KPROBE_FLAG_FTRACE;
+#else /* !CONFIG_KPROBES_ON_FTRACE */
+ return -EINVAL;
+#endif
+ }
+ return 0;
+}
+
+static int check_kprobe_address_safe(struct kprobe *p,
+ struct module **probed_mod)
+{
+ int ret;
+
+ ret = arch_check_ftrace_location(p);
+ if (ret)
+ return ret;
+ jump_label_lock();
+ preempt_disable();
+
+ /* Ensure it is not in reserved area nor out of text */
+ if (!kernel_text_address((unsigned long) p->addr) ||
+ within_kprobe_blacklist((unsigned long) p->addr) ||
+ jump_label_text_reserved(p->addr, p->addr)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Check if are we probing a module */
+ *probed_mod = __module_text_address((unsigned long) p->addr);
+ if (*probed_mod) {
+ /*
+ * We must hold a refcount of the probed module while updating
+ * its code to prohibit unexpected unloading.
+ */
+ if (unlikely(!try_module_get(*probed_mod))) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ /*
+ * 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);
+ *probed_mod = NULL;
+ ret = -ENOENT;
+ }
+ }
+out:
+ preempt_enable();
+ jump_label_unlock();
+
+ return ret;
+}
+
+int register_kprobe(struct kprobe *p)
+{
+ int ret;
+ struct kprobe *old_p;
+ struct module *probed_mod;
+ kprobe_opcode_t *addr;
+
+ /* Adjust probe address from symbol */
+ addr = kprobe_addr(p);
+ if (IS_ERR(addr))
+ return PTR_ERR(addr);
+ p->addr = addr;
+
+ ret = check_kprobe_rereg(p);
+ if (ret)
+ return ret;
+
+ /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
+ p->flags &= KPROBE_FLAG_DISABLED;
+ p->nmissed = 0;
+ INIT_LIST_HEAD(&p->list);
+
+ ret = check_kprobe_address_safe(p, &probed_mod);
+ if (ret)
+ return ret;
+
+ mutex_lock(&kprobe_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;
+ }
+
+ mutex_lock(&text_mutex); /* Avoiding text modification */
+ ret = prepare_kprobe(p);
+ mutex_unlock(&text_mutex);
+ 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(&kprobe_mutex);
+
+ if (probed_mod)
+ module_put(probed_mod);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(register_kprobe);
+
+/* Check if all probes on the aggrprobe are disabled */
+static int 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 *__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)) {
+ /*
+ * If kprobes_all_disarmed is set, orig_p
+ * should have already been disarmed, so
+ * skip unneed disarming process.
+ */
+ if (!kprobes_all_disarmed)
+ disarm_kprobe(orig_p, true);
+ orig_p->flags |= KPROBE_FLAG_DISABLED;
+ }
+ }
+
+ return orig_p;
+}
+
+/*
+ * Unregister a kprobe without a scheduler synchronization.
+ */
+static int __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 __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 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 unregister_kprobe(struct kprobe *p)
+{
+ unregister_kprobes(&p, 1);
+}
+EXPORT_SYMBOL_GPL(unregister_kprobe);
+
+void 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 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 register_jprobe(struct jprobe *jp)
+{
+ return register_jprobes(&jp, 1);
+}
+EXPORT_SYMBOL_GPL(register_jprobe);
+
+void unregister_jprobe(struct jprobe *jp)
+{
+ unregister_jprobes(&jp, 1);
+}
+EXPORT_SYMBOL_GPL(unregister_jprobe);
+
+void 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 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;
+
+ /*
+ * To avoid deadlocks, prohibit return probing in NMI contexts,
+ * just skip the probe and increase the (inexact) 'nmissed'
+ * statistical counter, so that the user is informed that
+ * something happened:
+ */
+ if (unlikely(in_nmi())) {
+ rp->nmissed++;
+ return 0;
+ }
+
+ /* 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)) {
+ raw_spin_lock_irqsave(&rp->lock, flags);
+ hlist_add_head(&ri->hlist, &rp->free_instances);
+ raw_spin_unlock_irqrestore(&rp->lock, flags);
+ 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;
+}
+NOKPROBE_SYMBOL(pre_handler_kretprobe);
+
+int 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 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 unregister_kretprobe(struct kretprobe *rp)
+{
+ unregister_kretprobes(&rp, 1);
+}
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
+
+void 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 register_kretprobe(struct kretprobe *rp)
+{
+ return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(register_kretprobe);
+
+int register_kretprobes(struct kretprobe **rps, int num)
+{
+ return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(register_kretprobes);
+
+void unregister_kretprobe(struct kretprobe *rp)
+{
+}
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
+
+void unregister_kretprobes(struct kretprobe **rps, int num)
+{
+}
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
+
+static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
+{
+ return 0;
+}
+NOKPROBE_SYMBOL(pre_handler_kretprobe);
+
+#endif /* CONFIG_KRETPROBES */
+
+/* Set the kprobe gone and remove its instruction buffer. */
+static void 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 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 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 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);
+}
+NOKPROBE_SYMBOL(dump_kprobe);
+
+/*
+ * 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.
+ */
+static int __init populate_kprobe_blacklist(unsigned long *start,
+ unsigned long *end)
+{
+ unsigned long *iter;
+ struct kprobe_blacklist_entry *ent;
+ unsigned long entry, offset = 0, size = 0;
+
+ for (iter = start; iter < end; iter++) {
+ entry = arch_deref_entry_point((void *)*iter);
+
+ if (!kernel_text_address(entry) ||
+ !kallsyms_lookup_size_offset(entry, &size, &offset)) {
+ pr_err("Failed to find blacklist at %p\n",
+ (void *)entry);
+ continue;
+ }
+
+ ent = kmalloc(sizeof(*ent), GFP_KERNEL);
+ if (!ent)
+ return -ENOMEM;
+ ent->start_addr = entry;
+ ent->end_addr = entry + size;
+ INIT_LIST_HEAD(&ent->list);
+ list_add_tail(&ent->list, &kprobe_blacklist);
+ }
+ return 0;
+}
+
+/* Module notifier call back, checking kprobes on the module */
+static int kprobes_module_callback(struct notifier_block *nb,
+ unsigned long val, void *data)
+{
+ struct module *mod = data;
+ struct hlist_head *head;
+ 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, 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
+};
+
+/* Markers of _kprobe_blacklist section */
+extern unsigned long __start_kprobe_blacklist[];
+extern unsigned long __stop_kprobe_blacklist[];
+
+static int __init init_kprobes(void)
+{
+ int i, err = 0;
+
+ /* 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));
+ }
+
+ err = populate_kprobe_blacklist(__start_kprobe_blacklist,
+ __stop_kprobe_blacklist);
+ if (err) {
+ pr_err("kprobes: failed to populate blacklist: %d\n", err);
+ pr_err("Please take care of using kprobes.\n");
+ }
+
+ 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 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%s\n",
+ (kprobe_gone(p) ? "[GONE]" : ""),
+ ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
+ (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
+ (kprobe_ftrace(pp) ? "[FTRACE]" : ""));
+}
+
+static void *kprobe_seq_start(struct seq_file *f, loff_t *pos)
+{
+ return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
+}
+
+static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
+{
+ (*pos)++;
+ if (*pos >= KPROBE_TABLE_SIZE)
+ return NULL;
+ return pos;
+}
+
+static void kprobe_seq_stop(struct seq_file *f, void *v)
+{
+ /* Nothing to do */
+}
+
+static int show_kprobe_addr(struct seq_file *pi, void *v)
+{
+ struct hlist_head *head;
+ struct kprobe *p, *kp;
+ const char *sym = NULL;
+ unsigned int i = *(loff_t *) v;
+ unsigned long offset = 0;
+ char *modname, namebuf[KSYM_NAME_LEN];
+
+ head = &kprobe_table[i];
+ preempt_disable();
+ hlist_for_each_entry_rcu(p, 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_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,
+};
+
+/* kprobes/blacklist -- shows which functions can not be probed */
+static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
+{
+ return seq_list_start(&kprobe_blacklist, *pos);
+}
+
+static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ return seq_list_next(v, &kprobe_blacklist, pos);
+}
+
+static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
+{
+ struct kprobe_blacklist_entry *ent =
+ list_entry(v, struct kprobe_blacklist_entry, list);
+
+ seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr,
+ (void *)ent->end_addr, (void *)ent->start_addr);
+ return 0;
+}
+
+static const struct seq_operations kprobe_blacklist_seq_ops = {
+ .start = kprobe_blacklist_seq_start,
+ .next = kprobe_blacklist_seq_next,
+ .stop = kprobe_seq_stop, /* Reuse void function */
+ .show = kprobe_blacklist_seq_show,
+};
+
+static int kprobe_blacklist_open(struct inode *inode, struct file *filp)
+{
+ return seq_open(filp, &kprobe_blacklist_seq_ops);
+}
+
+static const struct file_operations debugfs_kprobe_blacklist_ops = {
+ .open = kprobe_blacklist_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static void arm_all_kprobes(void)
+{
+ struct hlist_head *head;
+ struct kprobe *p;
+ unsigned int i;
+
+ mutex_lock(&kprobe_mutex);
+
+ /* If kprobes are armed, just return */
+ if (!kprobes_all_disarmed)
+ goto already_enabled;
+
+ /*
+ * optimize_kprobe() called by arm_kprobe() checks
+ * kprobes_all_disarmed, so set kprobes_all_disarmed before
+ * arm_kprobe.
+ */
+ kprobes_all_disarmed = false;
+ /* Arming kprobes doesn't optimize kprobe itself */
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry_rcu(p, head, hlist)
+ if (!kprobe_disabled(p))
+ arm_kprobe(p);
+ }
+
+ printk(KERN_INFO "Kprobes globally enabled\n");
+
+already_enabled:
+ mutex_unlock(&kprobe_mutex);
+ return;
+}
+
+static void disarm_all_kprobes(void)
+{
+ struct hlist_head *head;
+ 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");
+
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry_rcu(p, head, hlist) {
+ if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
+ disarm_kprobe(p, false);
+ }
+ }
+ 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;
+
+ buf[buf_size] = '\0';
+ switch (buf[0]) {
+ case 'y':
+ case 'Y':
+ case '1':
+ arm_all_kprobes();
+ break;
+ case 'n':
+ case 'N':
+ case '0':
+ disarm_all_kprobes();
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+static const struct file_operations fops_kp = {
+ .read = read_enabled_file_bool,
+ .write = write_enabled_file_bool,
+ .llseek = default_llseek,
+};
+
+static int __init 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)
+ goto error;
+
+ file = debugfs_create_file("enabled", 0600, dir,
+ &value, &fops_kp);
+ if (!file)
+ goto error;
+
+ file = debugfs_create_file("blacklist", 0444, dir, NULL,
+ &debugfs_kprobe_blacklist_ops);
+ if (!file)
+ goto error;
+
+ return 0;
+
+error:
+ debugfs_remove(dir);
+ return -ENOMEM;
+}
+
+late_initcall(debugfs_kprobe_init);
+#endif /* CONFIG_DEBUG_FS */
+
+module_init(init_kprobes);
+
+/* defined in arch/.../kernel/kprobes.c */
+EXPORT_SYMBOL_GPL(jprobe_return);
Code Review / kvmfornfv.git / blobdiff