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-rw-r--r--kernel/kprobes.c3041
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diff --git a/kernel/kprobes.c b/kernel/kprobes.c
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index 0000000000..b486504766
--- /dev/null
+++ b/kernel/kprobes.c
@@ -0,0 +1,3041 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Kernel Probes (KProbes)
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "kprobes: " fmt
+
+#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 <linux/static_call.h>
+#include <linux/perf_event.h>
+
+#include <asm/sections.h>
+#include <asm/cacheflush.h>
+#include <asm/errno.h>
+#include <linux/uaccess.h>
+
+#define KPROBE_HASH_BITS 6
+#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
+
+#if !defined(CONFIG_OPTPROBES) || !defined(CONFIG_SYSCTL)
+#define kprobe_sysctls_init() do { } while (0)
+#endif
+
+static int kprobes_initialized;
+/* kprobe_table can be accessed by
+ * - Normal hlist traversal and RCU add/del under 'kprobe_mutex' is held.
+ * Or
+ * - RCU hlist traversal under disabling preempt (breakpoint handlers)
+ */
+static struct hlist_head kprobe_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);
+
+kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
+ unsigned int __unused)
+{
+ return ((kprobe_opcode_t *)(kallsyms_lookup_name(name)));
+}
+
+/*
+ * Blacklist -- list of 'struct kprobe_blacklist_entry' to store info where
+ * kprobes can not probe.
+ */
+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,
+};
+
+void __weak *alloc_insn_page(void)
+{
+ /*
+ * Use module_alloc() so this page is within +/- 2GB of where the
+ * kernel image and loaded module images reside. This is required
+ * for most of the architectures.
+ * (e.g. x86-64 needs this to handle the %rip-relative fixups.)
+ */
+ 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,
+ .sym = KPROBE_INSN_PAGE_SYM,
+ .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;
+
+ /* Since the slot array is not protected by rcu, we need a mutex */
+ mutex_lock(&c->mutex);
+ retry:
+ rcu_read_lock();
+ list_for_each_entry_rcu(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);
+ rcu_read_unlock();
+ goto out;
+ }
+ }
+ /* kip->nused is broken. Fix it. */
+ kip->nused = slots_per_page(c);
+ WARN_ON(1);
+ }
+ }
+ rcu_read_unlock();
+
+ /* 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;
+
+ 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_rcu(&kip->list, &c->pages);
+ slot = kip->insns;
+
+ /* Record the perf ksymbol register event after adding the page */
+ perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, (unsigned long)kip->insns,
+ PAGE_SIZE, false, c->sym);
+out:
+ mutex_unlock(&c->mutex);
+ return slot;
+}
+
+/* Return true if all garbages are collected, otherwise false. */
+static bool 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)) {
+ /*
+ * Record perf ksymbol unregister event before removing
+ * the page.
+ */
+ perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
+ (unsigned long)kip->insns, PAGE_SIZE, true,
+ kip->cache->sym);
+ list_del_rcu(&kip->list);
+ synchronize_rcu();
+ kip->cache->free(kip->insns);
+ kfree(kip);
+ }
+ return true;
+ }
+ return false;
+}
+
+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_rcu();
+
+ 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;
+ long idx;
+
+ mutex_lock(&c->mutex);
+ rcu_read_lock();
+ list_for_each_entry_rcu(kip, &c->pages, list) {
+ idx = ((long)slot - (long)kip->insns) /
+ (c->insn_size * sizeof(kprobe_opcode_t));
+ if (idx >= 0 && idx < slots_per_page(c))
+ goto out;
+ }
+ /* Could not find this slot. */
+ WARN_ON(1);
+ kip = NULL;
+out:
+ rcu_read_unlock();
+ /* Mark and sweep: this may sleep */
+ if (kip) {
+ /* Check double free */
+ 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);
+ }
+ }
+ mutex_unlock(&c->mutex);
+}
+
+/*
+ * Check given address is on the page of kprobe instruction slots.
+ * This will be used for checking whether the address on a stack
+ * is on a text area or not.
+ */
+bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr)
+{
+ struct kprobe_insn_page *kip;
+ bool ret = false;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(kip, &c->pages, list) {
+ if (addr >= (unsigned long)kip->insns &&
+ addr < (unsigned long)kip->insns + PAGE_SIZE) {
+ ret = true;
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ return ret;
+}
+
+int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
+ unsigned long *value, char *type, char *sym)
+{
+ struct kprobe_insn_page *kip;
+ int ret = -ERANGE;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(kip, &c->pages, list) {
+ if ((*symnum)--)
+ continue;
+ strscpy(sym, c->sym, KSYM_NAME_LEN);
+ *type = 't';
+ *value = (unsigned long)kip->insns;
+ ret = 0;
+ break;
+ }
+ rcu_read_unlock();
+
+ return ret;
+}
+
+#ifdef CONFIG_OPTPROBES
+void __weak *alloc_optinsn_page(void)
+{
+ return alloc_insn_page();
+}
+
+void __weak free_optinsn_page(void *page)
+{
+ free_insn_page(page);
+}
+
+/* For optimized_kprobe buffer */
+struct kprobe_insn_cache kprobe_optinsn_slots = {
+ .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
+ .alloc = alloc_optinsn_page,
+ .free = free_optinsn_page,
+ .sym = KPROBE_OPTINSN_PAGE_SYM,
+ .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 architecture specific code.
+ */
+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,
+ lockdep_is_held(&kprobe_mutex)) {
+ 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 'p' is an aggregator */
+static inline bool kprobe_aggrprobe(struct kprobe *p)
+{
+ return p->pre_handler == aggr_pre_handler;
+}
+
+/* Return true if 'p' is unused */
+static inline bool 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: This is protected by 'kprobe_mutex'. */
+static bool kprobes_allow_optimization;
+
+/*
+ * Call all 'kprobe::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 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 if the kprobe is disarmed. Note: p must be on hash list */
+bool 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 if the probe is queued on (un)optimizing lists */
+static bool 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 true;
+ }
+ return false;
+}
+
+/*
+ * Return an optimized kprobe whose optimizing code replaces
+ * instructions including 'addr' (exclude breakpoint).
+ */
+static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *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 / sizeof(kprobe_opcode_t); i++)
+ p = get_kprobe(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)
+{
+ lockdep_assert_held(&text_mutex);
+ /*
+ * The optimization/unoptimization refers 'online_cpus' via
+ * stop_machine() and cpu-hotplug modifies the 'online_cpus'.
+ * And same time, 'text_mutex' will be held in cpu-hotplug and here.
+ * This combination can cause a deadlock (cpu-hotplug tries to lock
+ * 'text_mutex' but stop_machine() can not be done because
+ * the 'online_cpus' has been changed)
+ * To avoid this deadlock, caller must have locked cpu-hotplug
+ * for preventing cpu-hotplug outside of 'text_mutex' locking.
+ */
+ lockdep_assert_cpus_held();
+
+ /* Optimization never be done when disarmed */
+ if (kprobes_all_disarmed || !kprobes_allow_optimization ||
+ list_empty(&optimizing_list))
+ return;
+
+ arch_optimize_kprobes(&optimizing_list);
+}
+
+/*
+ * 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;
+
+ lockdep_assert_held(&text_mutex);
+ /* See comment in do_optimize_kprobes() */
+ lockdep_assert_cpus_held();
+
+ if (!list_empty(&unoptimizing_list))
+ arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
+
+ /* Loop on 'freeing_list' for disarming and removing from kprobe hash list */
+ list_for_each_entry_safe(op, tmp, &freeing_list, list) {
+ /* Switching from detour code to origin */
+ op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+ /* Disarm probes if marked disabled and not gone */
+ if (kprobe_disabled(&op->kp) && !kprobe_gone(&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);
+ }
+}
+
+/* Reclaim all kprobes on the 'freeing_list' */
+static void do_free_cleaned_kprobes(void)
+{
+ struct optimized_kprobe *op, *tmp;
+
+ list_for_each_entry_safe(op, tmp, &freeing_list, list) {
+ list_del_init(&op->list);
+ if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) {
+ /*
+ * This must not happen, but if there is a kprobe
+ * still in use, keep it on kprobes hash list.
+ */
+ continue;
+ }
+ 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);
+ cpus_read_lock();
+ mutex_lock(&text_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 potentially
+ * preempted tasks to have normally scheduled. Because optprobe
+ * may modify multiple instructions, there is a chance that Nth
+ * instruction is preempted. In that case, such tasks can return
+ * to 2nd-Nth byte of jump instruction. This wait is for avoiding it.
+ * Note that on non-preemptive kernel, this is transparently converted
+ * to synchronoze_sched() to wait for all interrupts to have completed.
+ */
+ synchronize_rcu_tasks();
+
+ /* Step 3: Optimize kprobes after quiesence period */
+ do_optimize_kprobes();
+
+ /* Step 4: Free cleaned kprobes after quiesence period */
+ do_free_cleaned_kprobes();
+
+ mutex_unlock(&text_mutex);
+ cpus_read_unlock();
+
+ /* Step 5: Kick optimizer again if needed */
+ if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
+ kick_kprobe_optimizer();
+
+ mutex_unlock(&kprobe_mutex);
+}
+
+/* Wait for completing optimization and unoptimization */
+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);
+}
+
+bool optprobe_queued_unopt(struct optimized_kprobe *op)
+{
+ struct optimized_kprobe *_op;
+
+ list_for_each_entry(_op, &unoptimizing_list, list) {
+ if (op == _op)
+ return true;
+ }
+
+ return false;
+}
+
+/* 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;
+
+ /* kprobes with 'post_handler' can not be optimized */
+ if (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) {
+ if (optprobe_queued_unopt(op)) {
+ /* This is under unoptimizing. Just dequeue the probe */
+ list_del_init(&op->list);
+ }
+ return;
+ }
+ op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
+
+ /*
+ * On the 'unoptimizing_list' and 'optimizing_list',
+ * 'op' must have OPTIMIZED flag
+ */
+ if (WARN_ON_ONCE(!list_empty(&op->list)))
+ return;
+
+ list_add(&op->list, &optimizing_list);
+ kick_kprobe_optimizer();
+}
+
+/* Short cut to direct unoptimizing */
+static void force_unoptimize_kprobe(struct optimized_kprobe *op)
+{
+ lockdep_assert_cpus_held();
+ arch_unoptimize_kprobe(op);
+ op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+}
+
+/* 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))
+ return;
+
+ if (!list_empty(&op->list)) {
+ if (optprobe_queued_unopt(op)) {
+ /* Queued in unoptimizing queue */
+ if (force) {
+ /*
+ * Forcibly unoptimize the kprobe here, and queue it
+ * in the freeing list for release afterwards.
+ */
+ force_unoptimize_kprobe(op);
+ list_move(&op->list, &freeing_list);
+ }
+ } else {
+ /* Dequeue from the optimizing queue */
+ list_del_init(&op->list);
+ op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+ }
+ 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 int reuse_unused_kprobe(struct kprobe *ap)
+{
+ struct optimized_kprobe *op;
+
+ /*
+ * 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);
+ WARN_ON_ONCE(list_empty(&op->list));
+ /* Enable the probe again */
+ ap->flags &= ~KPROBE_FLAG_DISABLED;
+ /* Optimize it again. (remove from 'op->list') */
+ if (!kprobe_optready(ap))
+ return -EINVAL;
+
+ optimize_kprobe(ap);
+ return 0;
+}
+
+/* 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)) {
+ /*
+ * Unused kprobe is on unoptimizing or freeing list. We move it
+ * to freeing_list and let the kprobe_optimizer() remove it from
+ * the kprobe hash list and free it.
+ */
+ if (optprobe_queued_unopt(op))
+ list_move(&op->list, &freeing_list);
+ }
+
+ /* Don't touch the code, because it is already freed. */
+ arch_remove_optimized_kprobe(op);
+}
+
+static inline
+void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
+{
+ if (!kprobe_ftrace(p))
+ arch_prepare_optimized_kprobe(op, p);
+}
+
+/* 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);
+ __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;
+ __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. */
+ cpus_read_lock();
+ 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();
+ cpus_read_unlock();
+}
+
+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;
+
+ cpus_read_lock();
+ kprobes_allow_optimization = true;
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry(p, head, hlist)
+ if (!kprobe_disabled(p))
+ optimize_kprobe(p);
+ }
+ cpus_read_unlock();
+ pr_info("kprobe jump-optimization is enabled. All kprobes are optimized if possible.\n");
+out:
+ mutex_unlock(&kprobe_mutex);
+}
+
+#ifdef CONFIG_SYSCTL
+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;
+ }
+
+ cpus_read_lock();
+ kprobes_allow_optimization = false;
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry(p, head, hlist) {
+ if (!kprobe_disabled(p))
+ unoptimize_kprobe(p, false);
+ }
+ }
+ cpus_read_unlock();
+ mutex_unlock(&kprobe_mutex);
+
+ /* Wait for unoptimizing completion. */
+ wait_for_kprobe_optimizer();
+ pr_info("kprobe jump-optimization is disabled. All kprobes are based on software breakpoint.\n");
+}
+
+static DEFINE_MUTEX(kprobe_sysctl_mutex);
+static int sysctl_kprobes_optimization;
+static int proc_kprobes_optimization_handler(struct ctl_table *table,
+ int write, void *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;
+}
+
+static struct ctl_table kprobe_sysctls[] = {
+ {
+ .procname = "kprobes-optimization",
+ .data = &sysctl_kprobes_optimization,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_kprobes_optimization_handler,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
+ {}
+};
+
+static void __init kprobe_sysctls_init(void)
+{
+ register_sysctl_init("debug", kprobe_sysctls);
+}
+#endif /* CONFIG_SYSCTL */
+
+/* Put a breakpoint for a probe. */
+static void __arm_kprobe(struct kprobe *p)
+{
+ struct kprobe *_p;
+
+ lockdep_assert_held(&text_mutex);
+
+ /* Find the overlapping optimized kprobes. */
+ _p = get_optimized_kprobe(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. */
+static void __disarm_kprobe(struct kprobe *p, bool reopt)
+{
+ struct kprobe *_p;
+
+ lockdep_assert_held(&text_mutex);
+
+ /* Try to unoptimize */
+ unoptimize_kprobe(p, kprobes_all_disarmed);
+
+ if (!kprobe_queued(p)) {
+ arch_disarm_kprobe(p);
+ /* If another kprobe was blocked, re-optimize it. */
+ _p = get_optimized_kprobe(p->addr);
+ if (unlikely(_p) && reopt)
+ optimize_kprobe(_p);
+ }
+ /*
+ * TODO: Since unoptimization and real disarming will be done by
+ * the worker thread, we can not check whether another probe are
+ * unoptimized because of this probe here. It should be re-optimized
+ * by the worker thread.
+ */
+}
+
+#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)
+
+static int reuse_unused_kprobe(struct kprobe *ap)
+{
+ /*
+ * If the optimized kprobe is NOT supported, the aggr kprobe is
+ * released at the same time that the last aggregated kprobe is
+ * unregistered.
+ * Thus there should be no chance to reuse unused kprobe.
+ */
+ WARN_ON_ONCE(1);
+ return -EINVAL;
+}
+
+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,
+};
+
+static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
+ .func = kprobe_ftrace_handler,
+ .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
+};
+
+static int kprobe_ipmodify_enabled;
+static int kprobe_ftrace_enabled;
+
+static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+ int *cnt)
+{
+ int ret;
+
+ lockdep_assert_held(&kprobe_mutex);
+
+ ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
+ if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret))
+ return ret;
+
+ if (*cnt == 0) {
+ ret = register_ftrace_function(ops);
+ if (WARN(ret < 0, "Failed to register kprobe-ftrace (error %d)\n", ret))
+ goto err_ftrace;
+ }
+
+ (*cnt)++;
+ return ret;
+
+err_ftrace:
+ /*
+ * At this point, sinec ops is not registered, we should be sefe from
+ * registering empty filter.
+ */
+ ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
+ return ret;
+}
+
+static int arm_kprobe_ftrace(struct kprobe *p)
+{
+ bool ipmodify = (p->post_handler != NULL);
+
+ return __arm_kprobe_ftrace(p,
+ ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+ ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
+
+static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+ int *cnt)
+{
+ int ret;
+
+ lockdep_assert_held(&kprobe_mutex);
+
+ if (*cnt == 1) {
+ ret = unregister_ftrace_function(ops);
+ if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (error %d)\n", ret))
+ return ret;
+ }
+
+ (*cnt)--;
+
+ ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
+ WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (error %d)\n",
+ p->addr, ret);
+ return ret;
+}
+
+static int disarm_kprobe_ftrace(struct kprobe *p)
+{
+ bool ipmodify = (p->post_handler != NULL);
+
+ return __disarm_kprobe_ftrace(p,
+ ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+ ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
+#else /* !CONFIG_KPROBES_ON_FTRACE */
+static inline int arm_kprobe_ftrace(struct kprobe *p)
+{
+ return -ENODEV;
+}
+
+static inline int disarm_kprobe_ftrace(struct kprobe *p)
+{
+ return -ENODEV;
+}
+#endif
+
+static int prepare_kprobe(struct kprobe *p)
+{
+ /* Must ensure p->addr is really on ftrace */
+ if (kprobe_ftrace(p))
+ return arch_prepare_kprobe_ftrace(p);
+
+ return arch_prepare_kprobe(p);
+}
+
+static int arm_kprobe(struct kprobe *kp)
+{
+ if (unlikely(kprobe_ftrace(kp)))
+ return arm_kprobe_ftrace(kp);
+
+ cpus_read_lock();
+ mutex_lock(&text_mutex);
+ __arm_kprobe(kp);
+ mutex_unlock(&text_mutex);
+ cpus_read_unlock();
+
+ return 0;
+}
+
+static int disarm_kprobe(struct kprobe *kp, bool reopt)
+{
+ if (unlikely(kprobe_ftrace(kp)))
+ return disarm_kprobe_ftrace(kp);
+
+ cpus_read_lock();
+ mutex_lock(&text_mutex);
+ __disarm_kprobe(kp, reopt);
+ mutex_unlock(&text_mutex);
+ cpus_read_unlock();
+
+ return 0;
+}
+
+/*
+ * 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);
+
+/* Walks the list and increments 'nmissed' if 'p' has child probes. */
+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++;
+ }
+}
+NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
+
+static struct kprobe kprobe_busy = {
+ .addr = (void *) get_kprobe,
+};
+
+void kprobe_busy_begin(void)
+{
+ struct kprobe_ctlblk *kcb;
+
+ preempt_disable();
+ __this_cpu_write(current_kprobe, &kprobe_busy);
+ kcb = get_kprobe_ctlblk();
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+}
+
+void kprobe_busy_end(void)
+{
+ __this_cpu_write(current_kprobe, NULL);
+ preempt_enable();
+}
+
+/* Add the new probe to 'ap->list'. */
+static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
+{
+ if (p->post_handler)
+ unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
+
+ 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 aggregator kprobe. Replace the
+ * earlier kprobe in the hlist with the aggregator kprobe.
+ */
+static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
+{
+ /* Copy the insn slot of 'p' 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;
+ /* We don't care the kprobe which has gone. */
+ if (p->post_handler && !kprobe_gone(p))
+ ap->post_handler = aggr_post_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 registers the second or subsequent kprobe at the same address.
+ */
+static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
+{
+ int ret = 0;
+ struct kprobe *ap = orig_p;
+
+ cpus_read_lock();
+
+ /* For preparing optimization, jump_label_text_reserved() is called */
+ jump_label_lock();
+ mutex_lock(&text_mutex);
+
+ if (!kprobe_aggrprobe(orig_p)) {
+ /* If 'orig_p' is not an 'aggr_kprobe', create new one. */
+ 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 */
+ ret = reuse_unused_kprobe(ap);
+ if (ret)
+ goto out;
+ }
+
+ 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 the 'ap'. 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 the insn slot of 'p' to 'ap'. */
+ copy_kprobe(ap, p);
+ ret = add_new_kprobe(ap, p);
+
+out:
+ mutex_unlock(&text_mutex);
+ jump_label_unlock();
+ cpus_read_unlock();
+
+ if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
+ ap->flags &= ~KPROBE_FLAG_DISABLED;
+ if (!kprobes_all_disarmed) {
+ /* Arm the breakpoint again. */
+ ret = arm_kprobe(ap);
+ if (ret) {
+ ap->flags |= KPROBE_FLAG_DISABLED;
+ list_del_rcu(&p->list);
+ synchronize_rcu();
+ }
+ }
+ }
+ return ret;
+}
+
+bool __weak arch_within_kprobe_blacklist(unsigned long addr)
+{
+ /* The '__kprobes' 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 'kprobe_blacklist' is defined, check the address and
+ * reject 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;
+}
+
+bool within_kprobe_blacklist(unsigned long addr)
+{
+ char symname[KSYM_NAME_LEN], *p;
+
+ if (__within_kprobe_blacklist(addr))
+ return true;
+
+ /* Check if the address is on a suffixed-symbol */
+ if (!lookup_symbol_name(addr, symname)) {
+ p = strchr(symname, '.');
+ if (!p)
+ return false;
+ *p = '\0';
+ addr = (unsigned long)kprobe_lookup_name(symname, 0);
+ if (addr)
+ return __within_kprobe_blacklist(addr);
+ }
+ return false;
+}
+
+/*
+ * arch_adjust_kprobe_addr - adjust the address
+ * @addr: symbol base address
+ * @offset: offset within the symbol
+ * @on_func_entry: was this @addr+@offset on the function entry
+ *
+ * Typically returns @addr + @offset, except for special cases where the
+ * function might be prefixed by a CFI landing pad, in that case any offset
+ * inside the landing pad is mapped to the first 'real' instruction of the
+ * symbol.
+ *
+ * Specifically, for things like IBT/BTI, skip the resp. ENDBR/BTI.C
+ * instruction at +0.
+ */
+kprobe_opcode_t *__weak arch_adjust_kprobe_addr(unsigned long addr,
+ unsigned long offset,
+ bool *on_func_entry)
+{
+ *on_func_entry = !offset;
+ return (kprobe_opcode_t *)(addr + offset);
+}
+
+/*
+ * If 'symbol_name' is specified, look it up and add the 'offset'
+ * 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(kprobe_opcode_t *addr, const char *symbol_name,
+ unsigned long offset, bool *on_func_entry)
+{
+ if ((symbol_name && addr) || (!symbol_name && !addr))
+ goto invalid;
+
+ if (symbol_name) {
+ /*
+ * Input: @sym + @offset
+ * Output: @addr + @offset
+ *
+ * NOTE: kprobe_lookup_name() does *NOT* fold the offset
+ * argument into it's output!
+ */
+ addr = kprobe_lookup_name(symbol_name, offset);
+ if (!addr)
+ return ERR_PTR(-ENOENT);
+ }
+
+ /*
+ * So here we have @addr + @offset, displace it into a new
+ * @addr' + @offset' where @addr' is the symbol start address.
+ */
+ addr = (void *)addr + offset;
+ if (!kallsyms_lookup_size_offset((unsigned long)addr, NULL, &offset))
+ return ERR_PTR(-ENOENT);
+ addr = (void *)addr - offset;
+
+ /*
+ * Then ask the architecture to re-combine them, taking care of
+ * magical function entry details while telling us if this was indeed
+ * at the start of the function.
+ */
+ addr = arch_adjust_kprobe_addr((unsigned long)addr, offset, on_func_entry);
+ if (addr)
+ return addr;
+
+invalid:
+ return ERR_PTR(-EINVAL);
+}
+
+static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
+{
+ bool on_func_entry;
+ return _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry);
+}
+
+/*
+ * Check the 'p' is valid and return the aggregator kprobe
+ * at the same address.
+ */
+static struct kprobe *__get_valid_kprobe(struct kprobe *p)
+{
+ struct kprobe *ap, *list_p;
+
+ lockdep_assert_held(&kprobe_mutex);
+
+ ap = get_kprobe(p->addr);
+ if (unlikely(!ap))
+ return NULL;
+
+ if (p != ap) {
+ list_for_each_entry(list_p, &ap->list, list)
+ if (list_p == p)
+ /* kprobe p is a valid probe */
+ goto valid;
+ return NULL;
+ }
+valid:
+ return ap;
+}
+
+/*
+ * Warn and return error if the kprobe is being re-registered since
+ * there must be a software bug.
+ */
+static inline int warn_kprobe_rereg(struct kprobe *p)
+{
+ int ret = 0;
+
+ mutex_lock(&kprobe_mutex);
+ if (WARN_ON_ONCE(__get_valid_kprobe(p)))
+ ret = -EINVAL;
+ mutex_unlock(&kprobe_mutex);
+
+ return ret;
+}
+
+static int check_ftrace_location(struct kprobe *p)
+{
+ unsigned long addr = (unsigned long)p->addr;
+
+ if (ftrace_location(addr) == addr) {
+#ifdef CONFIG_KPROBES_ON_FTRACE
+ p->flags |= KPROBE_FLAG_FTRACE;
+#else /* !CONFIG_KPROBES_ON_FTRACE */
+ return -EINVAL;
+#endif
+ }
+ return 0;
+}
+
+static bool is_cfi_preamble_symbol(unsigned long addr)
+{
+ char symbuf[KSYM_NAME_LEN];
+
+ if (lookup_symbol_name(addr, symbuf))
+ return false;
+
+ return str_has_prefix("__cfi_", symbuf) ||
+ str_has_prefix("__pfx_", symbuf);
+}
+
+static int check_kprobe_address_safe(struct kprobe *p,
+ struct module **probed_mod)
+{
+ int ret;
+
+ ret = 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 (!(core_kernel_text((unsigned long) p->addr) ||
+ is_module_text_address((unsigned long) p->addr)) ||
+ in_gate_area_no_mm((unsigned long) p->addr) ||
+ within_kprobe_blacklist((unsigned long) p->addr) ||
+ jump_label_text_reserved(p->addr, p->addr) ||
+ static_call_text_reserved(p->addr, p->addr) ||
+ find_bug((unsigned long)p->addr) ||
+ is_cfi_preamble_symbol((unsigned long)p->addr)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Check if 'p' is 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;
+ bool on_func_entry;
+
+ /* Adjust probe address from symbol */
+ addr = _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry);
+ if (IS_ERR(addr))
+ return PTR_ERR(addr);
+ p->addr = addr;
+
+ ret = warn_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);
+
+ if (on_func_entry)
+ p->flags |= KPROBE_FLAG_ON_FUNC_ENTRY;
+
+ 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;
+ }
+
+ cpus_read_lock();
+ /* Prevent text modification */
+ mutex_lock(&text_mutex);
+ ret = prepare_kprobe(p);
+ mutex_unlock(&text_mutex);
+ cpus_read_unlock();
+ 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)) {
+ ret = arm_kprobe(p);
+ if (ret) {
+ hlist_del_rcu(&p->hlist);
+ synchronize_rcu();
+ goto out;
+ }
+ }
+
+ /* 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 'ap' are disabled. */
+static bool aggr_kprobe_disabled(struct kprobe *ap)
+{
+ struct kprobe *kp;
+
+ lockdep_assert_held(&kprobe_mutex);
+
+ list_for_each_entry(kp, &ap->list, list)
+ if (!kprobe_disabled(kp))
+ /*
+ * Since there is an active probe on the list,
+ * we can't disable this 'ap'.
+ */
+ return false;
+
+ return true;
+}
+
+static struct kprobe *__disable_kprobe(struct kprobe *p)
+{
+ struct kprobe *orig_p;
+ int ret;
+
+ lockdep_assert_held(&kprobe_mutex);
+
+ /* Get an original kprobe for return */
+ orig_p = __get_valid_kprobe(p);
+ if (unlikely(orig_p == NULL))
+ return ERR_PTR(-EINVAL);
+
+ 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)) {
+ /*
+ * Don't be lazy here. Even if 'kprobes_all_disarmed'
+ * is false, 'orig_p' might not have been armed yet.
+ * Note arm_all_kprobes() __tries__ to arm all kprobes
+ * on the best effort basis.
+ */
+ if (!kprobes_all_disarmed && !kprobe_disabled(orig_p)) {
+ ret = disarm_kprobe(orig_p, true);
+ if (ret) {
+ p->flags &= ~KPROBE_FLAG_DISABLED;
+ return ERR_PTR(ret);
+ }
+ }
+ 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 (IS_ERR(ap))
+ return PTR_ERR(ap);
+
+ 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->post_handler && !kprobe_gone(p)) {
+ list_for_each_entry(list_p, &ap->list, list) {
+ if ((list_p != p) && (list_p->post_handler))
+ goto noclean;
+ }
+ /*
+ * For the kprobe-on-ftrace case, we keep the
+ * post_handler setting to identify this aggrprobe
+ * armed with kprobe_ipmodify_ops.
+ */
+ if (!kprobe_ftrace(ap))
+ 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:
+ 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_rcu();
+ for (i = 0; i < num; i++)
+ if (kps[i]->addr)
+ __unregister_kprobe_bottom(kps[i]);
+}
+EXPORT_SYMBOL_GPL(unregister_kprobes);
+
+int __weak kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ return NOTIFY_DONE;
+}
+NOKPROBE_SYMBOL(kprobe_exceptions_notify);
+
+static struct notifier_block kprobe_exceptions_nb = {
+ .notifier_call = kprobe_exceptions_notify,
+ .priority = 0x7fffffff /* we need to be notified first */
+};
+
+#ifdef CONFIG_KRETPROBES
+
+#if !defined(CONFIG_KRETPROBE_ON_RETHOOK)
+static void free_rp_inst_rcu(struct rcu_head *head)
+{
+ struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu);
+
+ if (refcount_dec_and_test(&ri->rph->ref))
+ kfree(ri->rph);
+ kfree(ri);
+}
+NOKPROBE_SYMBOL(free_rp_inst_rcu);
+
+static void recycle_rp_inst(struct kretprobe_instance *ri)
+{
+ struct kretprobe *rp = get_kretprobe(ri);
+
+ if (likely(rp))
+ freelist_add(&ri->freelist, &rp->freelist);
+ else
+ call_rcu(&ri->rcu, free_rp_inst_rcu);
+}
+NOKPROBE_SYMBOL(recycle_rp_inst);
+
+/*
+ * This function is called from delayed_put_task_struct() when a task is
+ * dead and cleaned up to recycle any kretprobe 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 llist_node *node;
+
+ /* Early boot, not yet initialized. */
+ if (unlikely(!kprobes_initialized))
+ return;
+
+ kprobe_busy_begin();
+
+ node = __llist_del_all(&tk->kretprobe_instances);
+ while (node) {
+ ri = container_of(node, struct kretprobe_instance, llist);
+ node = node->next;
+
+ recycle_rp_inst(ri);
+ }
+
+ kprobe_busy_end();
+}
+NOKPROBE_SYMBOL(kprobe_flush_task);
+
+static inline void free_rp_inst(struct kretprobe *rp)
+{
+ struct kretprobe_instance *ri;
+ struct freelist_node *node;
+ int count = 0;
+
+ node = rp->freelist.head;
+ while (node) {
+ ri = container_of(node, struct kretprobe_instance, freelist);
+ node = node->next;
+
+ kfree(ri);
+ count++;
+ }
+
+ if (refcount_sub_and_test(count, &rp->rph->ref)) {
+ kfree(rp->rph);
+ rp->rph = NULL;
+ }
+}
+
+/* This assumes the 'tsk' is the current task or the is not running. */
+static kprobe_opcode_t *__kretprobe_find_ret_addr(struct task_struct *tsk,
+ struct llist_node **cur)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct llist_node *node = *cur;
+
+ if (!node)
+ node = tsk->kretprobe_instances.first;
+ else
+ node = node->next;
+
+ while (node) {
+ ri = container_of(node, struct kretprobe_instance, llist);
+ if (ri->ret_addr != kretprobe_trampoline_addr()) {
+ *cur = node;
+ return ri->ret_addr;
+ }
+ node = node->next;
+ }
+ return NULL;
+}
+NOKPROBE_SYMBOL(__kretprobe_find_ret_addr);
+
+/**
+ * kretprobe_find_ret_addr -- Find correct return address modified by kretprobe
+ * @tsk: Target task
+ * @fp: A frame pointer
+ * @cur: a storage of the loop cursor llist_node pointer for next call
+ *
+ * Find the correct return address modified by a kretprobe on @tsk in unsigned
+ * long type. If it finds the return address, this returns that address value,
+ * or this returns 0.
+ * The @tsk must be 'current' or a task which is not running. @fp is a hint
+ * to get the currect return address - which is compared with the
+ * kretprobe_instance::fp field. The @cur is a loop cursor for searching the
+ * kretprobe return addresses on the @tsk. The '*@cur' should be NULL at the
+ * first call, but '@cur' itself must NOT NULL.
+ */
+unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
+ struct llist_node **cur)
+{
+ struct kretprobe_instance *ri = NULL;
+ kprobe_opcode_t *ret;
+
+ if (WARN_ON_ONCE(!cur))
+ return 0;
+
+ do {
+ ret = __kretprobe_find_ret_addr(tsk, cur);
+ if (!ret)
+ break;
+ ri = container_of(*cur, struct kretprobe_instance, llist);
+ } while (ri->fp != fp);
+
+ return (unsigned long)ret;
+}
+NOKPROBE_SYMBOL(kretprobe_find_ret_addr);
+
+void __weak arch_kretprobe_fixup_return(struct pt_regs *regs,
+ kprobe_opcode_t *correct_ret_addr)
+{
+ /*
+ * Do nothing by default. Please fill this to update the fake return
+ * address on the stack with the correct one on each arch if possible.
+ */
+}
+
+unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
+ void *frame_pointer)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct llist_node *first, *node = NULL;
+ kprobe_opcode_t *correct_ret_addr;
+ struct kretprobe *rp;
+
+ /* Find correct address and all nodes for this frame. */
+ correct_ret_addr = __kretprobe_find_ret_addr(current, &node);
+ if (!correct_ret_addr) {
+ pr_err("kretprobe: Return address not found, not execute handler. Maybe there is a bug in the kernel.\n");
+ BUG_ON(1);
+ }
+
+ /*
+ * Set the return address as the instruction pointer, because if the
+ * user handler calls stack_trace_save_regs() with this 'regs',
+ * the stack trace will start from the instruction pointer.
+ */
+ instruction_pointer_set(regs, (unsigned long)correct_ret_addr);
+
+ /* Run the user handler of the nodes. */
+ first = current->kretprobe_instances.first;
+ while (first) {
+ ri = container_of(first, struct kretprobe_instance, llist);
+
+ if (WARN_ON_ONCE(ri->fp != frame_pointer))
+ break;
+
+ rp = get_kretprobe(ri);
+ if (rp && rp->handler) {
+ struct kprobe *prev = kprobe_running();
+
+ __this_cpu_write(current_kprobe, &rp->kp);
+ ri->ret_addr = correct_ret_addr;
+ rp->handler(ri, regs);
+ __this_cpu_write(current_kprobe, prev);
+ }
+ if (first == node)
+ break;
+
+ first = first->next;
+ }
+
+ arch_kretprobe_fixup_return(regs, correct_ret_addr);
+
+ /* Unlink all nodes for this frame. */
+ first = current->kretprobe_instances.first;
+ current->kretprobe_instances.first = node->next;
+ node->next = NULL;
+
+ /* Recycle free instances. */
+ while (first) {
+ ri = container_of(first, struct kretprobe_instance, llist);
+ first = first->next;
+
+ recycle_rp_inst(ri);
+ }
+
+ return (unsigned long)correct_ret_addr;
+}
+NOKPROBE_SYMBOL(__kretprobe_trampoline_handler)
+
+/*
+ * 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);
+ struct kretprobe_instance *ri;
+ struct freelist_node *fn;
+
+ fn = freelist_try_get(&rp->freelist);
+ if (!fn) {
+ rp->nmissed++;
+ return 0;
+ }
+
+ ri = container_of(fn, struct kretprobe_instance, freelist);
+
+ if (rp->entry_handler && rp->entry_handler(ri, regs)) {
+ freelist_add(&ri->freelist, &rp->freelist);
+ return 0;
+ }
+
+ arch_prepare_kretprobe(ri, regs);
+
+ __llist_add(&ri->llist, &current->kretprobe_instances);
+
+ return 0;
+}
+NOKPROBE_SYMBOL(pre_handler_kretprobe);
+#else /* CONFIG_KRETPROBE_ON_RETHOOK */
+/*
+ * 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);
+ struct kretprobe_instance *ri;
+ struct rethook_node *rhn;
+
+ rhn = rethook_try_get(rp->rh);
+ if (!rhn) {
+ rp->nmissed++;
+ return 0;
+ }
+
+ ri = container_of(rhn, struct kretprobe_instance, node);
+
+ if (rp->entry_handler && rp->entry_handler(ri, regs))
+ rethook_recycle(rhn);
+ else
+ rethook_hook(rhn, regs, kprobe_ftrace(p));
+
+ return 0;
+}
+NOKPROBE_SYMBOL(pre_handler_kretprobe);
+
+static void kretprobe_rethook_handler(struct rethook_node *rh, void *data,
+ unsigned long ret_addr,
+ struct pt_regs *regs)
+{
+ struct kretprobe *rp = (struct kretprobe *)data;
+ struct kretprobe_instance *ri;
+ struct kprobe_ctlblk *kcb;
+
+ /* The data must NOT be null. This means rethook data structure is broken. */
+ if (WARN_ON_ONCE(!data) || !rp->handler)
+ return;
+
+ __this_cpu_write(current_kprobe, &rp->kp);
+ kcb = get_kprobe_ctlblk();
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+ ri = container_of(rh, struct kretprobe_instance, node);
+ rp->handler(ri, regs);
+
+ __this_cpu_write(current_kprobe, NULL);
+}
+NOKPROBE_SYMBOL(kretprobe_rethook_handler);
+
+#endif /* !CONFIG_KRETPROBE_ON_RETHOOK */
+
+/**
+ * kprobe_on_func_entry() -- check whether given address is function entry
+ * @addr: Target address
+ * @sym: Target symbol name
+ * @offset: The offset from the symbol or the address
+ *
+ * This checks whether the given @addr+@offset or @sym+@offset is on the
+ * function entry address or not.
+ * This returns 0 if it is the function entry, or -EINVAL if it is not.
+ * And also it returns -ENOENT if it fails the symbol or address lookup.
+ * Caller must pass @addr or @sym (either one must be NULL), or this
+ * returns -EINVAL.
+ */
+int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
+{
+ bool on_func_entry;
+ kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset, &on_func_entry);
+
+ if (IS_ERR(kp_addr))
+ return PTR_ERR(kp_addr);
+
+ if (!on_func_entry)
+ return -EINVAL;
+
+ return 0;
+}
+
+int register_kretprobe(struct kretprobe *rp)
+{
+ int ret;
+ struct kretprobe_instance *inst;
+ int i;
+ void *addr;
+
+ ret = kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset);
+ if (ret)
+ return ret;
+
+ /* If only 'rp->kp.addr' is specified, check reregistering kprobes */
+ if (rp->kp.addr && warn_kprobe_rereg(&rp->kp))
+ return -EINVAL;
+
+ 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;
+ }
+ }
+
+ if (rp->data_size > KRETPROBE_MAX_DATA_SIZE)
+ return -E2BIG;
+
+ rp->kp.pre_handler = pre_handler_kretprobe;
+ rp->kp.post_handler = NULL;
+
+ /* Pre-allocate memory for max kretprobe instances */
+ if (rp->maxactive <= 0)
+ rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
+
+#ifdef CONFIG_KRETPROBE_ON_RETHOOK
+ rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler);
+ if (!rp->rh)
+ return -ENOMEM;
+
+ for (i = 0; i < rp->maxactive; i++) {
+ inst = kzalloc(struct_size(inst, data, rp->data_size), GFP_KERNEL);
+ if (inst == NULL) {
+ rethook_free(rp->rh);
+ rp->rh = NULL;
+ return -ENOMEM;
+ }
+ rethook_add_node(rp->rh, &inst->node);
+ }
+ rp->nmissed = 0;
+ /* Establish function entry probe point */
+ ret = register_kprobe(&rp->kp);
+ if (ret != 0) {
+ rethook_free(rp->rh);
+ rp->rh = NULL;
+ }
+#else /* !CONFIG_KRETPROBE_ON_RETHOOK */
+ rp->freelist.head = NULL;
+ rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL);
+ if (!rp->rph)
+ return -ENOMEM;
+
+ rcu_assign_pointer(rp->rph->rp, rp);
+ for (i = 0; i < rp->maxactive; i++) {
+ inst = kzalloc(struct_size(inst, data, rp->data_size), GFP_KERNEL);
+ if (inst == NULL) {
+ refcount_set(&rp->rph->ref, i);
+ free_rp_inst(rp);
+ return -ENOMEM;
+ }
+ inst->rph = rp->rph;
+ freelist_add(&inst->freelist, &rp->freelist);
+ }
+ refcount_set(&rp->rph->ref, i);
+
+ rp->nmissed = 0;
+ /* Establish function entry probe point */
+ ret = register_kprobe(&rp->kp);
+ if (ret != 0)
+ free_rp_inst(rp);
+#endif
+ 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;
+#ifdef CONFIG_KRETPROBE_ON_RETHOOK
+ rethook_free(rps[i]->rh);
+#else
+ rcu_assign_pointer(rps[i]->rph->rp, NULL);
+#endif
+ }
+ mutex_unlock(&kprobe_mutex);
+
+ synchronize_rcu();
+ for (i = 0; i < num; i++) {
+ if (rps[i]->kp.addr) {
+ __unregister_kprobe_bottom(&rps[i]->kp);
+#ifndef CONFIG_KRETPROBE_ON_RETHOOK
+ free_rp_inst(rps[i]);
+#endif
+ }
+ }
+}
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
+
+#else /* CONFIG_KRETPROBES */
+int register_kretprobe(struct kretprobe *rp)
+{
+ return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(register_kretprobe);
+
+int register_kretprobes(struct kretprobe **rps, int num)
+{
+ return -EOPNOTSUPP;
+}
+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;
+
+ lockdep_assert_held(&kprobe_mutex);
+
+ /*
+ * The module is going away. We should disarm the kprobe which
+ * is using ftrace, because ftrace framework is still available at
+ * 'MODULE_STATE_GOING' notification.
+ */
+ if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed)
+ disarm_kprobe_ftrace(p);
+
+ 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(kp, &p->list, list)
+ kp->flags |= KPROBE_FLAG_GONE;
+ p->post_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;
+ struct kprobe *p;
+
+ mutex_lock(&kprobe_mutex);
+
+ /* Disable this kprobe */
+ p = __disable_kprobe(kp);
+ if (IS_ERR(p))
+ ret = PTR_ERR(p);
+
+ 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;
+ ret = arm_kprobe(p);
+ if (ret) {
+ p->flags |= KPROBE_FLAG_DISABLED;
+ if (p != kp)
+ kp->flags |= KPROBE_FLAG_DISABLED;
+ }
+ }
+out:
+ mutex_unlock(&kprobe_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(enable_kprobe);
+
+/* Caller must NOT call this in usual path. This is only for critical case */
+void dump_kprobe(struct kprobe *kp)
+{
+ pr_err("Dump kprobe:\n.symbol_name = %s, .offset = %x, .addr = %pS\n",
+ kp->symbol_name, kp->offset, kp->addr);
+}
+NOKPROBE_SYMBOL(dump_kprobe);
+
+int kprobe_add_ksym_blacklist(unsigned long entry)
+{
+ struct kprobe_blacklist_entry *ent;
+ unsigned long offset = 0, size = 0;
+
+ if (!kernel_text_address(entry) ||
+ !kallsyms_lookup_size_offset(entry, &size, &offset))
+ return -EINVAL;
+
+ 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 (int)size;
+}
+
+/* Add all symbols in given area into kprobe blacklist */
+int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
+{
+ unsigned long entry;
+ int ret = 0;
+
+ for (entry = start; entry < end; entry += ret) {
+ ret = kprobe_add_ksym_blacklist(entry);
+ if (ret < 0)
+ return ret;
+ if (ret == 0) /* In case of alias symbol */
+ ret = 1;
+ }
+ return 0;
+}
+
+/* Remove all symbols in given area from kprobe blacklist */
+static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
+{
+ struct kprobe_blacklist_entry *ent, *n;
+
+ list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
+ if (ent->start_addr < start || ent->start_addr >= end)
+ continue;
+ list_del(&ent->list);
+ kfree(ent);
+ }
+}
+
+static void kprobe_remove_ksym_blacklist(unsigned long entry)
+{
+ kprobe_remove_area_blacklist(entry, entry + 1);
+}
+
+int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
+ char *type, char *sym)
+{
+ return -ERANGE;
+}
+
+int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
+ char *sym)
+{
+#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
+ if (!kprobe_cache_get_kallsym(&kprobe_insn_slots, &symnum, value, type, sym))
+ return 0;
+#ifdef CONFIG_OPTPROBES
+ if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots, &symnum, value, type, sym))
+ return 0;
+#endif
+#endif
+ if (!arch_kprobe_get_kallsym(&symnum, value, type, sym))
+ return 0;
+ return -ERANGE;
+}
+
+int __init __weak arch_populate_kprobe_blacklist(void)
+{
+ return 0;
+}
+
+/*
+ * 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 entry;
+ unsigned long *iter;
+ int ret;
+
+ for (iter = start; iter < end; iter++) {
+ entry = (unsigned long)dereference_symbol_descriptor((void *)*iter);
+ ret = kprobe_add_ksym_blacklist(entry);
+ if (ret == -EINVAL)
+ continue;
+ if (ret < 0)
+ return ret;
+ }
+
+ /* Symbols in '__kprobes_text' are blacklisted */
+ ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start,
+ (unsigned long)__kprobes_text_end);
+ if (ret)
+ return ret;
+
+ /* Symbols in 'noinstr' section are blacklisted */
+ ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start,
+ (unsigned long)__noinstr_text_end);
+
+ return ret ? : arch_populate_kprobe_blacklist();
+}
+
+static void add_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+ int i;
+
+ if (mod->kprobe_blacklist) {
+ for (i = 0; i < mod->num_kprobe_blacklist; i++)
+ kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]);
+ }
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_add_area_blacklist(start, end);
+ }
+
+ start = (unsigned long)mod->noinstr_text_start;
+ if (start) {
+ end = start + mod->noinstr_text_size;
+ kprobe_add_area_blacklist(start, end);
+ }
+}
+
+static void remove_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+ int i;
+
+ if (mod->kprobe_blacklist) {
+ for (i = 0; i < mod->num_kprobe_blacklist; i++)
+ kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]);
+ }
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_remove_area_blacklist(start, end);
+ }
+
+ start = (unsigned long)mod->noinstr_text_start;
+ if (start) {
+ end = start + mod->noinstr_text_size;
+ kprobe_remove_area_blacklist(start, end);
+ }
+}
+
+/* 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_COMING) {
+ mutex_lock(&kprobe_mutex);
+ add_module_kprobe_blacklist(mod);
+ mutex_unlock(&kprobe_mutex);
+ }
+ 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(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.
+ *
+ * Note, this will also move any optimized probes
+ * that are pending to be removed from their
+ * corresponding lists to the 'freeing_list' and
+ * will not be touched by the delayed
+ * kprobe_optimizer() work handler.
+ */
+ kill_kprobe(p);
+ }
+ }
+ if (val == MODULE_STATE_GOING)
+ remove_module_kprobe_blacklist(mod);
+ mutex_unlock(&kprobe_mutex);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block kprobe_module_nb = {
+ .notifier_call = kprobes_module_callback,
+ .priority = 0
+};
+
+void kprobe_free_init_mem(void)
+{
+ void *start = (void *)(&__init_begin);
+ void *end = (void *)(&__init_end);
+ struct hlist_head *head;
+ struct kprobe *p;
+ int i;
+
+ mutex_lock(&kprobe_mutex);
+
+ /* Kill all kprobes on initmem because the target code has been freed. */
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry(p, head, hlist) {
+ if (start <= (void *)p->addr && (void *)p->addr < end)
+ kill_kprobe(p);
+ }
+ }
+
+ mutex_unlock(&kprobe_mutex);
+}
+
+static int __init init_kprobes(void)
+{
+ int i, err;
+
+ /* 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]);
+
+ err = populate_kprobe_blacklist(__start_kprobe_blacklist,
+ __stop_kprobe_blacklist);
+ if (err)
+ pr_err("Failed to populate blacklist (error %d), kprobes not restricted, be careful using them!\n", err);
+
+ if (kretprobe_blacklist_size) {
+ /* lookup the function address from its name */
+ for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
+ kretprobe_blacklist[i].addr =
+ kprobe_lookup_name(kretprobe_blacklist[i].name, 0);
+ if (!kretprobe_blacklist[i].addr)
+ pr_err("Failed to lookup symbol '%s' for kretprobe blacklist. Maybe the target function is removed or renamed.\n",
+ kretprobe_blacklist[i].name);
+ }
+ }
+
+ /* By default, kprobes are armed */
+ kprobes_all_disarmed = false;
+
+#if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT)
+ /* Init 'kprobe_optinsn_slots' for allocation */
+ kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
+#endif
+
+ 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);
+ kprobe_sysctls_init();
+ return err;
+}
+early_initcall(init_kprobes);
+
+#if defined(CONFIG_OPTPROBES)
+static int __init init_optprobes(void)
+{
+ /*
+ * Enable kprobe optimization - this kicks the optimizer which
+ * depends on synchronize_rcu_tasks() and ksoftirqd, that is
+ * not spawned in early initcall. So delay the optimization.
+ */
+ optimize_all_kprobes();
+
+ return 0;
+}
+subsys_initcall(init_optprobes);
+#endif
+
+#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;
+ void *addr = p->addr;
+
+ if (p->pre_handler == pre_handler_kretprobe)
+ kprobe_type = "r";
+ else
+ kprobe_type = "k";
+
+ if (!kallsyms_show_value(pi->file->f_cred))
+ addr = NULL;
+
+ if (sym)
+ seq_printf(pi, "%px %s %s+0x%x %s ",
+ addr, kprobe_type, sym, offset,
+ (modname ? modname : " "));
+ else /* try to use %pS */
+ seq_printf(pi, "%px %s %pS ",
+ 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_sops = {
+ .start = kprobe_seq_start,
+ .next = kprobe_seq_next,
+ .stop = kprobe_seq_stop,
+ .show = show_kprobe_addr
+};
+
+DEFINE_SEQ_ATTRIBUTE(kprobes);
+
+/* kprobes/blacklist -- shows which functions can not be probed */
+static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
+{
+ mutex_lock(&kprobe_mutex);
+ 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);
+
+ /*
+ * If '/proc/kallsyms' is not showing kernel address, we won't
+ * show them here either.
+ */
+ if (!kallsyms_show_value(m->file->f_cred))
+ seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL,
+ (void *)ent->start_addr);
+ else
+ seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr,
+ (void *)ent->end_addr, (void *)ent->start_addr);
+ return 0;
+}
+
+static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v)
+{
+ mutex_unlock(&kprobe_mutex);
+}
+
+static const struct seq_operations kprobe_blacklist_sops = {
+ .start = kprobe_blacklist_seq_start,
+ .next = kprobe_blacklist_seq_next,
+ .stop = kprobe_blacklist_seq_stop,
+ .show = kprobe_blacklist_seq_show,
+};
+DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist);
+
+static int arm_all_kprobes(void)
+{
+ struct hlist_head *head;
+ struct kprobe *p;
+ unsigned int i, total = 0, errors = 0;
+ int err, ret = 0;
+
+ 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];
+ /* Arm all kprobes on a best-effort basis */
+ hlist_for_each_entry(p, head, hlist) {
+ if (!kprobe_disabled(p)) {
+ err = arm_kprobe(p);
+ if (err) {
+ errors++;
+ ret = err;
+ }
+ total++;
+ }
+ }
+ }
+
+ if (errors)
+ pr_warn("Kprobes globally enabled, but failed to enable %d out of %d probes. Please check which kprobes are kept disabled via debugfs.\n",
+ errors, total);
+ else
+ pr_info("Kprobes globally enabled\n");
+
+already_enabled:
+ mutex_unlock(&kprobe_mutex);
+ return ret;
+}
+
+static int disarm_all_kprobes(void)
+{
+ struct hlist_head *head;
+ struct kprobe *p;
+ unsigned int i, total = 0, errors = 0;
+ int err, ret = 0;
+
+ mutex_lock(&kprobe_mutex);
+
+ /* If kprobes are already disarmed, just return */
+ if (kprobes_all_disarmed) {
+ mutex_unlock(&kprobe_mutex);
+ return 0;
+ }
+
+ kprobes_all_disarmed = true;
+
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ /* Disarm all kprobes on a best-effort basis */
+ hlist_for_each_entry(p, head, hlist) {
+ if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
+ err = disarm_kprobe(p, false);
+ if (err) {
+ errors++;
+ ret = err;
+ }
+ total++;
+ }
+ }
+ }
+
+ if (errors)
+ pr_warn("Kprobes globally disabled, but failed to disable %d out of %d probes. Please check which kprobes are kept enabled via debugfs.\n",
+ errors, total);
+ else
+ pr_info("Kprobes globally disabled\n");
+
+ mutex_unlock(&kprobe_mutex);
+
+ /* Wait for disarming all kprobes by optimizer */
+ wait_for_kprobe_optimizer();
+
+ return ret;
+}
+
+/*
+ * 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)
+{
+ bool enable;
+ int ret;
+
+ ret = kstrtobool_from_user(user_buf, count, &enable);
+ if (ret)
+ return ret;
+
+ ret = enable ? arm_all_kprobes() : disarm_all_kprobes();
+ if (ret)
+ return ret;
+
+ 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;
+
+ dir = debugfs_create_dir("kprobes", NULL);
+
+ debugfs_create_file("list", 0400, dir, NULL, &kprobes_fops);
+
+ debugfs_create_file("enabled", 0600, dir, NULL, &fops_kp);
+
+ debugfs_create_file("blacklist", 0400, dir, NULL,
+ &kprobe_blacklist_fops);
+
+ return 0;
+}
+
+late_initcall(debugfs_kprobe_init);
+#endif /* CONFIG_DEBUG_FS */