mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 16:16:41 +07:00
f986a499ef
register_kprobe() aborts if the address of the new request falls in a prohibited area (such as ftrace pouch, __kprobes annotated functions, non-kernel text addresses, jump label text). We however don't return the right error on this abort, resulting in a silent failure - incorrect adding/reporting of kprobes ('perf probe do_fork+18' or 'perf probe mcount' for instance). In V2 we are incorporating Masami Hiramatsu's feedback. This patch fixes it by returning -EINVAL upon failure. While we are here, rename the label used for exit to be more appropriate. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Prashanth K Nageshappa <prashanth@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Jason Baron <jbaron@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2268 lines
56 KiB
C
2268 lines
56 KiB
C
/*
|
|
* Kernel Probes (KProbes)
|
|
* kernel/kprobes.c
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*
|
|
* Copyright (C) IBM Corporation, 2002, 2004
|
|
*
|
|
* 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
|
|
* Probes initial implementation (includes suggestions from
|
|
* Rusty Russell).
|
|
* 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
|
|
* hlists and exceptions notifier as suggested by Andi Kleen.
|
|
* 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
|
|
* interface to access function arguments.
|
|
* 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
|
|
* exceptions notifier to be first on the priority list.
|
|
* 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
|
|
* <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
|
|
* <prasanna@in.ibm.com> added function-return probes.
|
|
*/
|
|
#include <linux/kprobes.h>
|
|
#include <linux/hash.h>
|
|
#include <linux/init.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/stddef.h>
|
|
#include <linux/export.h>
|
|
#include <linux/moduleloader.h>
|
|
#include <linux/kallsyms.h>
|
|
#include <linux/freezer.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/debugfs.h>
|
|
#include <linux/sysctl.h>
|
|
#include <linux/kdebug.h>
|
|
#include <linux/memory.h>
|
|
#include <linux/ftrace.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/jump_label.h>
|
|
|
|
#include <asm-generic/sections.h>
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/errno.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
#define KPROBE_HASH_BITS 6
|
|
#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
|
|
|
|
|
|
/*
|
|
* Some oddball architectures like 64bit powerpc have function descriptors
|
|
* so this must be overridable.
|
|
*/
|
|
#ifndef kprobe_lookup_name
|
|
#define kprobe_lookup_name(name, addr) \
|
|
addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
|
|
#endif
|
|
|
|
static int kprobes_initialized;
|
|
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
|
|
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
|
|
|
|
/* NOTE: change this value only with kprobe_mutex held */
|
|
static bool kprobes_all_disarmed;
|
|
|
|
/* This protects kprobe_table and optimizing_list */
|
|
static DEFINE_MUTEX(kprobe_mutex);
|
|
static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
|
|
static struct {
|
|
raw_spinlock_t lock ____cacheline_aligned_in_smp;
|
|
} kretprobe_table_locks[KPROBE_TABLE_SIZE];
|
|
|
|
static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
|
|
{
|
|
return &(kretprobe_table_locks[hash].lock);
|
|
}
|
|
|
|
/*
|
|
* Normally, functions that we'd want to prohibit kprobes in, are marked
|
|
* __kprobes. But, there are cases where such functions already belong to
|
|
* a different section (__sched for preempt_schedule)
|
|
*
|
|
* For such cases, we now have a blacklist
|
|
*/
|
|
static struct kprobe_blackpoint kprobe_blacklist[] = {
|
|
{"preempt_schedule",},
|
|
{"native_get_debugreg",},
|
|
{"irq_entries_start",},
|
|
{"common_interrupt",},
|
|
{"mcount",}, /* mcount can be called from everywhere */
|
|
{NULL} /* Terminator */
|
|
};
|
|
|
|
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
|
|
/*
|
|
* kprobe->ainsn.insn points to the copy of the instruction to be
|
|
* single-stepped. x86_64, POWER4 and above have no-exec support and
|
|
* stepping on the instruction on a vmalloced/kmalloced/data page
|
|
* is a recipe for disaster
|
|
*/
|
|
struct kprobe_insn_page {
|
|
struct list_head list;
|
|
kprobe_opcode_t *insns; /* Page of instruction slots */
|
|
int nused;
|
|
int ngarbage;
|
|
char slot_used[];
|
|
};
|
|
|
|
#define KPROBE_INSN_PAGE_SIZE(slots) \
|
|
(offsetof(struct kprobe_insn_page, slot_used) + \
|
|
(sizeof(char) * (slots)))
|
|
|
|
struct kprobe_insn_cache {
|
|
struct list_head pages; /* list of kprobe_insn_page */
|
|
size_t insn_size; /* size of instruction slot */
|
|
int nr_garbage;
|
|
};
|
|
|
|
static int slots_per_page(struct kprobe_insn_cache *c)
|
|
{
|
|
return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
|
|
}
|
|
|
|
enum kprobe_slot_state {
|
|
SLOT_CLEAN = 0,
|
|
SLOT_DIRTY = 1,
|
|
SLOT_USED = 2,
|
|
};
|
|
|
|
static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */
|
|
static struct kprobe_insn_cache kprobe_insn_slots = {
|
|
.pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
|
|
.insn_size = MAX_INSN_SIZE,
|
|
.nr_garbage = 0,
|
|
};
|
|
static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
|
|
|
|
/**
|
|
* __get_insn_slot() - Find a slot on an executable page for an instruction.
|
|
* We allocate an executable page if there's no room on existing ones.
|
|
*/
|
|
static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
|
|
{
|
|
struct kprobe_insn_page *kip;
|
|
|
|
retry:
|
|
list_for_each_entry(kip, &c->pages, list) {
|
|
if (kip->nused < slots_per_page(c)) {
|
|
int i;
|
|
for (i = 0; i < slots_per_page(c); i++) {
|
|
if (kip->slot_used[i] == SLOT_CLEAN) {
|
|
kip->slot_used[i] = SLOT_USED;
|
|
kip->nused++;
|
|
return kip->insns + (i * c->insn_size);
|
|
}
|
|
}
|
|
/* kip->nused is broken. Fix it. */
|
|
kip->nused = slots_per_page(c);
|
|
WARN_ON(1);
|
|
}
|
|
}
|
|
|
|
/* If there are any garbage slots, collect it and try again. */
|
|
if (c->nr_garbage && collect_garbage_slots(c) == 0)
|
|
goto retry;
|
|
|
|
/* All out of space. Need to allocate a new page. */
|
|
kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
|
|
if (!kip)
|
|
return NULL;
|
|
|
|
/*
|
|
* Use module_alloc so this page is within +/- 2GB of where the
|
|
* kernel image and loaded module images reside. This is required
|
|
* so x86_64 can correctly handle the %rip-relative fixups.
|
|
*/
|
|
kip->insns = module_alloc(PAGE_SIZE);
|
|
if (!kip->insns) {
|
|
kfree(kip);
|
|
return NULL;
|
|
}
|
|
INIT_LIST_HEAD(&kip->list);
|
|
memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
|
|
kip->slot_used[0] = SLOT_USED;
|
|
kip->nused = 1;
|
|
kip->ngarbage = 0;
|
|
list_add(&kip->list, &c->pages);
|
|
return kip->insns;
|
|
}
|
|
|
|
|
|
kprobe_opcode_t __kprobes *get_insn_slot(void)
|
|
{
|
|
kprobe_opcode_t *ret = NULL;
|
|
|
|
mutex_lock(&kprobe_insn_mutex);
|
|
ret = __get_insn_slot(&kprobe_insn_slots);
|
|
mutex_unlock(&kprobe_insn_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Return 1 if all garbages are collected, otherwise 0. */
|
|
static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
|
|
{
|
|
kip->slot_used[idx] = SLOT_CLEAN;
|
|
kip->nused--;
|
|
if (kip->nused == 0) {
|
|
/*
|
|
* Page is no longer in use. Free it unless
|
|
* it's the last one. We keep the last one
|
|
* so as not to have to set it up again the
|
|
* next time somebody inserts a probe.
|
|
*/
|
|
if (!list_is_singular(&kip->list)) {
|
|
list_del(&kip->list);
|
|
module_free(NULL, kip->insns);
|
|
kfree(kip);
|
|
}
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
|
|
{
|
|
struct kprobe_insn_page *kip, *next;
|
|
|
|
/* Ensure no-one is interrupted on the garbages */
|
|
synchronize_sched();
|
|
|
|
list_for_each_entry_safe(kip, next, &c->pages, list) {
|
|
int i;
|
|
if (kip->ngarbage == 0)
|
|
continue;
|
|
kip->ngarbage = 0; /* we will collect all garbages */
|
|
for (i = 0; i < slots_per_page(c); i++) {
|
|
if (kip->slot_used[i] == SLOT_DIRTY &&
|
|
collect_one_slot(kip, i))
|
|
break;
|
|
}
|
|
}
|
|
c->nr_garbage = 0;
|
|
return 0;
|
|
}
|
|
|
|
static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
|
|
kprobe_opcode_t *slot, int dirty)
|
|
{
|
|
struct kprobe_insn_page *kip;
|
|
|
|
list_for_each_entry(kip, &c->pages, list) {
|
|
long idx = ((long)slot - (long)kip->insns) /
|
|
(c->insn_size * sizeof(kprobe_opcode_t));
|
|
if (idx >= 0 && idx < slots_per_page(c)) {
|
|
WARN_ON(kip->slot_used[idx] != SLOT_USED);
|
|
if (dirty) {
|
|
kip->slot_used[idx] = SLOT_DIRTY;
|
|
kip->ngarbage++;
|
|
if (++c->nr_garbage > slots_per_page(c))
|
|
collect_garbage_slots(c);
|
|
} else
|
|
collect_one_slot(kip, idx);
|
|
return;
|
|
}
|
|
}
|
|
/* Could not free this slot. */
|
|
WARN_ON(1);
|
|
}
|
|
|
|
void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
|
|
{
|
|
mutex_lock(&kprobe_insn_mutex);
|
|
__free_insn_slot(&kprobe_insn_slots, slot, dirty);
|
|
mutex_unlock(&kprobe_insn_mutex);
|
|
}
|
|
#ifdef CONFIG_OPTPROBES
|
|
/* For optimized_kprobe buffer */
|
|
static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
|
|
static struct kprobe_insn_cache kprobe_optinsn_slots = {
|
|
.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
|
|
/* .insn_size is initialized later */
|
|
.nr_garbage = 0,
|
|
};
|
|
/* Get a slot for optimized_kprobe buffer */
|
|
kprobe_opcode_t __kprobes *get_optinsn_slot(void)
|
|
{
|
|
kprobe_opcode_t *ret = NULL;
|
|
|
|
mutex_lock(&kprobe_optinsn_mutex);
|
|
ret = __get_insn_slot(&kprobe_optinsn_slots);
|
|
mutex_unlock(&kprobe_optinsn_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
|
|
{
|
|
mutex_lock(&kprobe_optinsn_mutex);
|
|
__free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
|
|
mutex_unlock(&kprobe_optinsn_mutex);
|
|
}
|
|
#endif
|
|
#endif
|
|
|
|
/* We have preemption disabled.. so it is safe to use __ versions */
|
|
static inline void set_kprobe_instance(struct kprobe *kp)
|
|
{
|
|
__this_cpu_write(kprobe_instance, kp);
|
|
}
|
|
|
|
static inline void reset_kprobe_instance(void)
|
|
{
|
|
__this_cpu_write(kprobe_instance, NULL);
|
|
}
|
|
|
|
/*
|
|
* This routine is called either:
|
|
* - under the kprobe_mutex - during kprobe_[un]register()
|
|
* OR
|
|
* - with preemption disabled - from arch/xxx/kernel/kprobes.c
|
|
*/
|
|
struct kprobe __kprobes *get_kprobe(void *addr)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node;
|
|
struct kprobe *p;
|
|
|
|
head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
|
|
hlist_for_each_entry_rcu(p, node, head, hlist) {
|
|
if (p->addr == addr)
|
|
return p;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
|
|
|
|
/* Return true if the kprobe is an aggregator */
|
|
static inline int kprobe_aggrprobe(struct kprobe *p)
|
|
{
|
|
return p->pre_handler == aggr_pre_handler;
|
|
}
|
|
|
|
/* Return true(!0) if the kprobe is unused */
|
|
static inline int kprobe_unused(struct kprobe *p)
|
|
{
|
|
return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
|
|
list_empty(&p->list);
|
|
}
|
|
|
|
/*
|
|
* Keep all fields in the kprobe consistent
|
|
*/
|
|
static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
|
|
{
|
|
memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
|
|
memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
|
|
}
|
|
|
|
#ifdef CONFIG_OPTPROBES
|
|
/* NOTE: change this value only with kprobe_mutex held */
|
|
static bool kprobes_allow_optimization;
|
|
|
|
/*
|
|
* Call all pre_handler on the list, but ignores its return value.
|
|
* This must be called from arch-dep optimized caller.
|
|
*/
|
|
void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct kprobe *kp;
|
|
|
|
list_for_each_entry_rcu(kp, &p->list, list) {
|
|
if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
|
|
set_kprobe_instance(kp);
|
|
kp->pre_handler(kp, regs);
|
|
}
|
|
reset_kprobe_instance();
|
|
}
|
|
}
|
|
|
|
/* Free optimized instructions and optimized_kprobe */
|
|
static __kprobes void free_aggr_kprobe(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
arch_remove_optimized_kprobe(op);
|
|
arch_remove_kprobe(p);
|
|
kfree(op);
|
|
}
|
|
|
|
/* Return true(!0) if the kprobe is ready for optimization. */
|
|
static inline int kprobe_optready(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
if (kprobe_aggrprobe(p)) {
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
return arch_prepared_optinsn(&op->optinsn);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
|
|
static inline int kprobe_disarmed(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
/* If kprobe is not aggr/opt probe, just return kprobe is disabled */
|
|
if (!kprobe_aggrprobe(p))
|
|
return kprobe_disabled(p);
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
|
|
return kprobe_disabled(p) && list_empty(&op->list);
|
|
}
|
|
|
|
/* Return true(!0) if the probe is queued on (un)optimizing lists */
|
|
static int __kprobes kprobe_queued(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
if (kprobe_aggrprobe(p)) {
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
if (!list_empty(&op->list))
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Return an optimized kprobe whose optimizing code replaces
|
|
* instructions including addr (exclude breakpoint).
|
|
*/
|
|
static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
|
|
{
|
|
int i;
|
|
struct kprobe *p = NULL;
|
|
struct optimized_kprobe *op;
|
|
|
|
/* Don't check i == 0, since that is a breakpoint case. */
|
|
for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
|
|
p = get_kprobe((void *)(addr - i));
|
|
|
|
if (p && kprobe_optready(p)) {
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
if (arch_within_optimized_kprobe(op, addr))
|
|
return p;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* Optimization staging list, protected by kprobe_mutex */
|
|
static LIST_HEAD(optimizing_list);
|
|
static LIST_HEAD(unoptimizing_list);
|
|
|
|
static void kprobe_optimizer(struct work_struct *work);
|
|
static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
|
|
static DECLARE_COMPLETION(optimizer_comp);
|
|
#define OPTIMIZE_DELAY 5
|
|
|
|
/*
|
|
* Optimize (replace a breakpoint with a jump) kprobes listed on
|
|
* optimizing_list.
|
|
*/
|
|
static __kprobes void do_optimize_kprobes(void)
|
|
{
|
|
/* Optimization never be done when disarmed */
|
|
if (kprobes_all_disarmed || !kprobes_allow_optimization ||
|
|
list_empty(&optimizing_list))
|
|
return;
|
|
|
|
/*
|
|
* The optimization/unoptimization refers online_cpus via
|
|
* stop_machine() and cpu-hotplug modifies online_cpus.
|
|
* And same time, text_mutex will be held in cpu-hotplug and here.
|
|
* This combination can cause a deadlock (cpu-hotplug try to lock
|
|
* text_mutex but stop_machine can not be done because online_cpus
|
|
* has been changed)
|
|
* To avoid this deadlock, we need to call get_online_cpus()
|
|
* for preventing cpu-hotplug outside of text_mutex locking.
|
|
*/
|
|
get_online_cpus();
|
|
mutex_lock(&text_mutex);
|
|
arch_optimize_kprobes(&optimizing_list);
|
|
mutex_unlock(&text_mutex);
|
|
put_online_cpus();
|
|
}
|
|
|
|
/*
|
|
* Unoptimize (replace a jump with a breakpoint and remove the breakpoint
|
|
* if need) kprobes listed on unoptimizing_list.
|
|
*/
|
|
static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
|
|
{
|
|
struct optimized_kprobe *op, *tmp;
|
|
|
|
/* Unoptimization must be done anytime */
|
|
if (list_empty(&unoptimizing_list))
|
|
return;
|
|
|
|
/* Ditto to do_optimize_kprobes */
|
|
get_online_cpus();
|
|
mutex_lock(&text_mutex);
|
|
arch_unoptimize_kprobes(&unoptimizing_list, free_list);
|
|
/* Loop free_list for disarming */
|
|
list_for_each_entry_safe(op, tmp, free_list, list) {
|
|
/* Disarm probes if marked disabled */
|
|
if (kprobe_disabled(&op->kp))
|
|
arch_disarm_kprobe(&op->kp);
|
|
if (kprobe_unused(&op->kp)) {
|
|
/*
|
|
* Remove unused probes from hash list. After waiting
|
|
* for synchronization, these probes are reclaimed.
|
|
* (reclaiming is done by do_free_cleaned_kprobes.)
|
|
*/
|
|
hlist_del_rcu(&op->kp.hlist);
|
|
} else
|
|
list_del_init(&op->list);
|
|
}
|
|
mutex_unlock(&text_mutex);
|
|
put_online_cpus();
|
|
}
|
|
|
|
/* Reclaim all kprobes on the free_list */
|
|
static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list)
|
|
{
|
|
struct optimized_kprobe *op, *tmp;
|
|
|
|
list_for_each_entry_safe(op, tmp, free_list, list) {
|
|
BUG_ON(!kprobe_unused(&op->kp));
|
|
list_del_init(&op->list);
|
|
free_aggr_kprobe(&op->kp);
|
|
}
|
|
}
|
|
|
|
/* Start optimizer after OPTIMIZE_DELAY passed */
|
|
static __kprobes void kick_kprobe_optimizer(void)
|
|
{
|
|
if (!delayed_work_pending(&optimizing_work))
|
|
schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
|
|
}
|
|
|
|
/* Kprobe jump optimizer */
|
|
static __kprobes void kprobe_optimizer(struct work_struct *work)
|
|
{
|
|
LIST_HEAD(free_list);
|
|
|
|
/* Lock modules while optimizing kprobes */
|
|
mutex_lock(&module_mutex);
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
/*
|
|
* Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
|
|
* kprobes before waiting for quiesence period.
|
|
*/
|
|
do_unoptimize_kprobes(&free_list);
|
|
|
|
/*
|
|
* Step 2: Wait for quiesence period to ensure all running interrupts
|
|
* are done. Because optprobe may modify multiple instructions
|
|
* there is a chance that Nth instruction is interrupted. In that
|
|
* case, running interrupt can return to 2nd-Nth byte of jump
|
|
* instruction. This wait is for avoiding it.
|
|
*/
|
|
synchronize_sched();
|
|
|
|
/* Step 3: Optimize kprobes after quiesence period */
|
|
do_optimize_kprobes();
|
|
|
|
/* Step 4: Free cleaned kprobes after quiesence period */
|
|
do_free_cleaned_kprobes(&free_list);
|
|
|
|
mutex_unlock(&kprobe_mutex);
|
|
mutex_unlock(&module_mutex);
|
|
|
|
/* Step 5: Kick optimizer again if needed */
|
|
if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
|
|
kick_kprobe_optimizer();
|
|
else
|
|
/* Wake up all waiters */
|
|
complete_all(&optimizer_comp);
|
|
}
|
|
|
|
/* Wait for completing optimization and unoptimization */
|
|
static __kprobes void wait_for_kprobe_optimizer(void)
|
|
{
|
|
if (delayed_work_pending(&optimizing_work))
|
|
wait_for_completion(&optimizer_comp);
|
|
}
|
|
|
|
/* Optimize kprobe if p is ready to be optimized */
|
|
static __kprobes void optimize_kprobe(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
/* Check if the kprobe is disabled or not ready for optimization. */
|
|
if (!kprobe_optready(p) || !kprobes_allow_optimization ||
|
|
(kprobe_disabled(p) || kprobes_all_disarmed))
|
|
return;
|
|
|
|
/* Both of break_handler and post_handler are not supported. */
|
|
if (p->break_handler || p->post_handler)
|
|
return;
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
|
|
/* Check there is no other kprobes at the optimized instructions */
|
|
if (arch_check_optimized_kprobe(op) < 0)
|
|
return;
|
|
|
|
/* Check if it is already optimized. */
|
|
if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
|
|
return;
|
|
op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
|
|
|
|
if (!list_empty(&op->list))
|
|
/* This is under unoptimizing. Just dequeue the probe */
|
|
list_del_init(&op->list);
|
|
else {
|
|
list_add(&op->list, &optimizing_list);
|
|
kick_kprobe_optimizer();
|
|
}
|
|
}
|
|
|
|
/* Short cut to direct unoptimizing */
|
|
static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op)
|
|
{
|
|
get_online_cpus();
|
|
arch_unoptimize_kprobe(op);
|
|
put_online_cpus();
|
|
if (kprobe_disabled(&op->kp))
|
|
arch_disarm_kprobe(&op->kp);
|
|
}
|
|
|
|
/* Unoptimize a kprobe if p is optimized */
|
|
static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
|
|
return; /* This is not an optprobe nor optimized */
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
if (!kprobe_optimized(p)) {
|
|
/* Unoptimized or unoptimizing case */
|
|
if (force && !list_empty(&op->list)) {
|
|
/*
|
|
* Only if this is unoptimizing kprobe and forced,
|
|
* forcibly unoptimize it. (No need to unoptimize
|
|
* unoptimized kprobe again :)
|
|
*/
|
|
list_del_init(&op->list);
|
|
force_unoptimize_kprobe(op);
|
|
}
|
|
return;
|
|
}
|
|
|
|
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
|
|
if (!list_empty(&op->list)) {
|
|
/* Dequeue from the optimization queue */
|
|
list_del_init(&op->list);
|
|
return;
|
|
}
|
|
/* Optimized kprobe case */
|
|
if (force)
|
|
/* Forcibly update the code: this is a special case */
|
|
force_unoptimize_kprobe(op);
|
|
else {
|
|
list_add(&op->list, &unoptimizing_list);
|
|
kick_kprobe_optimizer();
|
|
}
|
|
}
|
|
|
|
/* Cancel unoptimizing for reusing */
|
|
static void reuse_unused_kprobe(struct kprobe *ap)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
BUG_ON(!kprobe_unused(ap));
|
|
/*
|
|
* Unused kprobe MUST be on the way of delayed unoptimizing (means
|
|
* there is still a relative jump) and disabled.
|
|
*/
|
|
op = container_of(ap, struct optimized_kprobe, kp);
|
|
if (unlikely(list_empty(&op->list)))
|
|
printk(KERN_WARNING "Warning: found a stray unused "
|
|
"aggrprobe@%p\n", ap->addr);
|
|
/* Enable the probe again */
|
|
ap->flags &= ~KPROBE_FLAG_DISABLED;
|
|
/* Optimize it again (remove from op->list) */
|
|
BUG_ON(!kprobe_optready(ap));
|
|
optimize_kprobe(ap);
|
|
}
|
|
|
|
/* Remove optimized instructions */
|
|
static void __kprobes kill_optimized_kprobe(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
if (!list_empty(&op->list))
|
|
/* Dequeue from the (un)optimization queue */
|
|
list_del_init(&op->list);
|
|
|
|
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
|
|
/* Don't touch the code, because it is already freed. */
|
|
arch_remove_optimized_kprobe(op);
|
|
}
|
|
|
|
/* Try to prepare optimized instructions */
|
|
static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
arch_prepare_optimized_kprobe(op);
|
|
}
|
|
|
|
/* Allocate new optimized_kprobe and try to prepare optimized instructions */
|
|
static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
|
|
if (!op)
|
|
return NULL;
|
|
|
|
INIT_LIST_HEAD(&op->list);
|
|
op->kp.addr = p->addr;
|
|
arch_prepare_optimized_kprobe(op);
|
|
|
|
return &op->kp;
|
|
}
|
|
|
|
static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
|
|
|
|
/*
|
|
* Prepare an optimized_kprobe and optimize it
|
|
* NOTE: p must be a normal registered kprobe
|
|
*/
|
|
static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *ap;
|
|
struct optimized_kprobe *op;
|
|
|
|
ap = alloc_aggr_kprobe(p);
|
|
if (!ap)
|
|
return;
|
|
|
|
op = container_of(ap, struct optimized_kprobe, kp);
|
|
if (!arch_prepared_optinsn(&op->optinsn)) {
|
|
/* If failed to setup optimizing, fallback to kprobe */
|
|
arch_remove_optimized_kprobe(op);
|
|
kfree(op);
|
|
return;
|
|
}
|
|
|
|
init_aggr_kprobe(ap, p);
|
|
optimize_kprobe(ap);
|
|
}
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
/* This should be called with kprobe_mutex locked */
|
|
static void __kprobes optimize_all_kprobes(void)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
|
|
/* If optimization is already allowed, just return */
|
|
if (kprobes_allow_optimization)
|
|
return;
|
|
|
|
kprobes_allow_optimization = true;
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, node, head, hlist)
|
|
if (!kprobe_disabled(p))
|
|
optimize_kprobe(p);
|
|
}
|
|
printk(KERN_INFO "Kprobes globally optimized\n");
|
|
}
|
|
|
|
/* This should be called with kprobe_mutex locked */
|
|
static void __kprobes unoptimize_all_kprobes(void)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
|
|
/* If optimization is already prohibited, just return */
|
|
if (!kprobes_allow_optimization)
|
|
return;
|
|
|
|
kprobes_allow_optimization = false;
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, node, head, hlist) {
|
|
if (!kprobe_disabled(p))
|
|
unoptimize_kprobe(p, false);
|
|
}
|
|
}
|
|
/* Wait for unoptimizing completion */
|
|
wait_for_kprobe_optimizer();
|
|
printk(KERN_INFO "Kprobes globally unoptimized\n");
|
|
}
|
|
|
|
int sysctl_kprobes_optimization;
|
|
int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
|
|
void __user *buffer, size_t *length,
|
|
loff_t *ppos)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
|
|
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
|
|
|
|
if (sysctl_kprobes_optimization)
|
|
optimize_all_kprobes();
|
|
else
|
|
unoptimize_all_kprobes();
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_SYSCTL */
|
|
|
|
/* Put a breakpoint for a probe. Must be called with text_mutex locked */
|
|
static void __kprobes __arm_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *_p;
|
|
|
|
/* Check collision with other optimized kprobes */
|
|
_p = get_optimized_kprobe((unsigned long)p->addr);
|
|
if (unlikely(_p))
|
|
/* Fallback to unoptimized kprobe */
|
|
unoptimize_kprobe(_p, true);
|
|
|
|
arch_arm_kprobe(p);
|
|
optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
|
|
}
|
|
|
|
/* Remove the breakpoint of a probe. Must be called with text_mutex locked */
|
|
static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt)
|
|
{
|
|
struct kprobe *_p;
|
|
|
|
unoptimize_kprobe(p, false); /* Try to unoptimize */
|
|
|
|
if (!kprobe_queued(p)) {
|
|
arch_disarm_kprobe(p);
|
|
/* If another kprobe was blocked, optimize it. */
|
|
_p = get_optimized_kprobe((unsigned long)p->addr);
|
|
if (unlikely(_p) && reopt)
|
|
optimize_kprobe(_p);
|
|
}
|
|
/* TODO: reoptimize others after unoptimized this probe */
|
|
}
|
|
|
|
#else /* !CONFIG_OPTPROBES */
|
|
|
|
#define optimize_kprobe(p) do {} while (0)
|
|
#define unoptimize_kprobe(p, f) do {} while (0)
|
|
#define kill_optimized_kprobe(p) do {} while (0)
|
|
#define prepare_optimized_kprobe(p) do {} while (0)
|
|
#define try_to_optimize_kprobe(p) do {} while (0)
|
|
#define __arm_kprobe(p) arch_arm_kprobe(p)
|
|
#define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
|
|
#define kprobe_disarmed(p) kprobe_disabled(p)
|
|
#define wait_for_kprobe_optimizer() do {} while (0)
|
|
|
|
/* There should be no unused kprobes can be reused without optimization */
|
|
static void reuse_unused_kprobe(struct kprobe *ap)
|
|
{
|
|
printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
|
|
BUG_ON(kprobe_unused(ap));
|
|
}
|
|
|
|
static __kprobes void free_aggr_kprobe(struct kprobe *p)
|
|
{
|
|
arch_remove_kprobe(p);
|
|
kfree(p);
|
|
}
|
|
|
|
static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
|
|
{
|
|
return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
|
|
}
|
|
#endif /* CONFIG_OPTPROBES */
|
|
|
|
/* Arm a kprobe with text_mutex */
|
|
static void __kprobes arm_kprobe(struct kprobe *kp)
|
|
{
|
|
/*
|
|
* Here, since __arm_kprobe() doesn't use stop_machine(),
|
|
* this doesn't cause deadlock on text_mutex. So, we don't
|
|
* need get_online_cpus().
|
|
*/
|
|
mutex_lock(&text_mutex);
|
|
__arm_kprobe(kp);
|
|
mutex_unlock(&text_mutex);
|
|
}
|
|
|
|
/* Disarm a kprobe with text_mutex */
|
|
static void __kprobes disarm_kprobe(struct kprobe *kp)
|
|
{
|
|
/* Ditto */
|
|
mutex_lock(&text_mutex);
|
|
__disarm_kprobe(kp, true);
|
|
mutex_unlock(&text_mutex);
|
|
}
|
|
|
|
/*
|
|
* Aggregate handlers for multiple kprobes support - these handlers
|
|
* take care of invoking the individual kprobe handlers on p->list
|
|
*/
|
|
static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct kprobe *kp;
|
|
|
|
list_for_each_entry_rcu(kp, &p->list, list) {
|
|
if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
|
|
set_kprobe_instance(kp);
|
|
if (kp->pre_handler(kp, regs))
|
|
return 1;
|
|
}
|
|
reset_kprobe_instance();
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
|
|
unsigned long flags)
|
|
{
|
|
struct kprobe *kp;
|
|
|
|
list_for_each_entry_rcu(kp, &p->list, list) {
|
|
if (kp->post_handler && likely(!kprobe_disabled(kp))) {
|
|
set_kprobe_instance(kp);
|
|
kp->post_handler(kp, regs, flags);
|
|
reset_kprobe_instance();
|
|
}
|
|
}
|
|
}
|
|
|
|
static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
|
|
int trapnr)
|
|
{
|
|
struct kprobe *cur = __this_cpu_read(kprobe_instance);
|
|
|
|
/*
|
|
* if we faulted "during" the execution of a user specified
|
|
* probe handler, invoke just that probe's fault handler
|
|
*/
|
|
if (cur && cur->fault_handler) {
|
|
if (cur->fault_handler(cur, regs, trapnr))
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct kprobe *cur = __this_cpu_read(kprobe_instance);
|
|
int ret = 0;
|
|
|
|
if (cur && cur->break_handler) {
|
|
if (cur->break_handler(cur, regs))
|
|
ret = 1;
|
|
}
|
|
reset_kprobe_instance();
|
|
return ret;
|
|
}
|
|
|
|
/* Walks the list and increments nmissed count for multiprobe case */
|
|
void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
|
|
{
|
|
struct kprobe *kp;
|
|
if (!kprobe_aggrprobe(p)) {
|
|
p->nmissed++;
|
|
} else {
|
|
list_for_each_entry_rcu(kp, &p->list, list)
|
|
kp->nmissed++;
|
|
}
|
|
return;
|
|
}
|
|
|
|
void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
|
|
struct hlist_head *head)
|
|
{
|
|
struct kretprobe *rp = ri->rp;
|
|
|
|
/* remove rp inst off the rprobe_inst_table */
|
|
hlist_del(&ri->hlist);
|
|
INIT_HLIST_NODE(&ri->hlist);
|
|
if (likely(rp)) {
|
|
raw_spin_lock(&rp->lock);
|
|
hlist_add_head(&ri->hlist, &rp->free_instances);
|
|
raw_spin_unlock(&rp->lock);
|
|
} else
|
|
/* Unregistering */
|
|
hlist_add_head(&ri->hlist, head);
|
|
}
|
|
|
|
void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
|
|
struct hlist_head **head, unsigned long *flags)
|
|
__acquires(hlist_lock)
|
|
{
|
|
unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
|
|
raw_spinlock_t *hlist_lock;
|
|
|
|
*head = &kretprobe_inst_table[hash];
|
|
hlist_lock = kretprobe_table_lock_ptr(hash);
|
|
raw_spin_lock_irqsave(hlist_lock, *flags);
|
|
}
|
|
|
|
static void __kprobes kretprobe_table_lock(unsigned long hash,
|
|
unsigned long *flags)
|
|
__acquires(hlist_lock)
|
|
{
|
|
raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
|
|
raw_spin_lock_irqsave(hlist_lock, *flags);
|
|
}
|
|
|
|
void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
|
|
unsigned long *flags)
|
|
__releases(hlist_lock)
|
|
{
|
|
unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
|
|
raw_spinlock_t *hlist_lock;
|
|
|
|
hlist_lock = kretprobe_table_lock_ptr(hash);
|
|
raw_spin_unlock_irqrestore(hlist_lock, *flags);
|
|
}
|
|
|
|
static void __kprobes kretprobe_table_unlock(unsigned long hash,
|
|
unsigned long *flags)
|
|
__releases(hlist_lock)
|
|
{
|
|
raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
|
|
raw_spin_unlock_irqrestore(hlist_lock, *flags);
|
|
}
|
|
|
|
/*
|
|
* This function is called from finish_task_switch when task tk becomes dead,
|
|
* so that we can recycle any function-return probe instances associated
|
|
* with this task. These left over instances represent probed functions
|
|
* that have been called but will never return.
|
|
*/
|
|
void __kprobes kprobe_flush_task(struct task_struct *tk)
|
|
{
|
|
struct kretprobe_instance *ri;
|
|
struct hlist_head *head, empty_rp;
|
|
struct hlist_node *node, *tmp;
|
|
unsigned long hash, flags = 0;
|
|
|
|
if (unlikely(!kprobes_initialized))
|
|
/* Early boot. kretprobe_table_locks not yet initialized. */
|
|
return;
|
|
|
|
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, node, tmp, head, hlist) {
|
|
if (ri->task == tk)
|
|
recycle_rp_inst(ri, &empty_rp);
|
|
}
|
|
kretprobe_table_unlock(hash, &flags);
|
|
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
|
|
hlist_del(&ri->hlist);
|
|
kfree(ri);
|
|
}
|
|
}
|
|
|
|
static inline void free_rp_inst(struct kretprobe *rp)
|
|
{
|
|
struct kretprobe_instance *ri;
|
|
struct hlist_node *pos, *next;
|
|
|
|
hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
|
|
hlist_del(&ri->hlist);
|
|
kfree(ri);
|
|
}
|
|
}
|
|
|
|
static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
|
|
{
|
|
unsigned long flags, hash;
|
|
struct kretprobe_instance *ri;
|
|
struct hlist_node *pos, *next;
|
|
struct hlist_head *head;
|
|
|
|
/* No race here */
|
|
for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
|
|
kretprobe_table_lock(hash, &flags);
|
|
head = &kretprobe_inst_table[hash];
|
|
hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
|
|
if (ri->rp == rp)
|
|
ri->rp = NULL;
|
|
}
|
|
kretprobe_table_unlock(hash, &flags);
|
|
}
|
|
free_rp_inst(rp);
|
|
}
|
|
|
|
/*
|
|
* Add the new probe to ap->list. Fail if this is the
|
|
* second jprobe at the address - two jprobes can't coexist
|
|
*/
|
|
static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
|
|
{
|
|
BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
|
|
|
|
if (p->break_handler || p->post_handler)
|
|
unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
|
|
|
|
if (p->break_handler) {
|
|
if (ap->break_handler)
|
|
return -EEXIST;
|
|
list_add_tail_rcu(&p->list, &ap->list);
|
|
ap->break_handler = aggr_break_handler;
|
|
} else
|
|
list_add_rcu(&p->list, &ap->list);
|
|
if (p->post_handler && !ap->post_handler)
|
|
ap->post_handler = aggr_post_handler;
|
|
|
|
if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
|
|
ap->flags &= ~KPROBE_FLAG_DISABLED;
|
|
if (!kprobes_all_disarmed)
|
|
/* Arm the breakpoint again. */
|
|
__arm_kprobe(ap);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Fill in the required fields of the "manager kprobe". Replace the
|
|
* earlier kprobe in the hlist with the manager kprobe
|
|
*/
|
|
static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
|
|
{
|
|
/* Copy p's insn slot to ap */
|
|
copy_kprobe(p, ap);
|
|
flush_insn_slot(ap);
|
|
ap->addr = p->addr;
|
|
ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
|
|
ap->pre_handler = aggr_pre_handler;
|
|
ap->fault_handler = aggr_fault_handler;
|
|
/* We don't care the kprobe which has gone. */
|
|
if (p->post_handler && !kprobe_gone(p))
|
|
ap->post_handler = aggr_post_handler;
|
|
if (p->break_handler && !kprobe_gone(p))
|
|
ap->break_handler = aggr_break_handler;
|
|
|
|
INIT_LIST_HEAD(&ap->list);
|
|
INIT_HLIST_NODE(&ap->hlist);
|
|
|
|
list_add_rcu(&p->list, &ap->list);
|
|
hlist_replace_rcu(&p->hlist, &ap->hlist);
|
|
}
|
|
|
|
/*
|
|
* This is the second or subsequent kprobe at the address - handle
|
|
* the intricacies
|
|
*/
|
|
static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
|
|
struct kprobe *p)
|
|
{
|
|
int ret = 0;
|
|
struct kprobe *ap = orig_p;
|
|
|
|
if (!kprobe_aggrprobe(orig_p)) {
|
|
/* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
|
|
ap = alloc_aggr_kprobe(orig_p);
|
|
if (!ap)
|
|
return -ENOMEM;
|
|
init_aggr_kprobe(ap, orig_p);
|
|
} else if (kprobe_unused(ap))
|
|
/* This probe is going to die. Rescue it */
|
|
reuse_unused_kprobe(ap);
|
|
|
|
if (kprobe_gone(ap)) {
|
|
/*
|
|
* Attempting to insert new probe at the same location that
|
|
* had a probe in the module vaddr area which already
|
|
* freed. So, the instruction slot has already been
|
|
* released. We need a new slot for the new probe.
|
|
*/
|
|
ret = arch_prepare_kprobe(ap);
|
|
if (ret)
|
|
/*
|
|
* Even if fail to allocate new slot, don't need to
|
|
* free aggr_probe. It will be used next time, or
|
|
* freed by unregister_kprobe.
|
|
*/
|
|
return ret;
|
|
|
|
/* Prepare optimized instructions if possible. */
|
|
prepare_optimized_kprobe(ap);
|
|
|
|
/*
|
|
* Clear gone flag to prevent allocating new slot again, and
|
|
* set disabled flag because it is not armed yet.
|
|
*/
|
|
ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
|
|
| KPROBE_FLAG_DISABLED;
|
|
}
|
|
|
|
/* Copy ap's insn slot to p */
|
|
copy_kprobe(ap, p);
|
|
return add_new_kprobe(ap, p);
|
|
}
|
|
|
|
static int __kprobes in_kprobes_functions(unsigned long addr)
|
|
{
|
|
struct kprobe_blackpoint *kb;
|
|
|
|
if (addr >= (unsigned long)__kprobes_text_start &&
|
|
addr < (unsigned long)__kprobes_text_end)
|
|
return -EINVAL;
|
|
/*
|
|
* If there exists a kprobe_blacklist, verify and
|
|
* fail any probe registration in the prohibited area
|
|
*/
|
|
for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
|
|
if (kb->start_addr) {
|
|
if (addr >= kb->start_addr &&
|
|
addr < (kb->start_addr + kb->range))
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* If we have a symbol_name argument, look it up and add the offset field
|
|
* to it. This way, we can specify a relative address to a symbol.
|
|
* This returns encoded errors if it fails to look up symbol or invalid
|
|
* combination of parameters.
|
|
*/
|
|
static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
|
|
{
|
|
kprobe_opcode_t *addr = p->addr;
|
|
|
|
if ((p->symbol_name && p->addr) ||
|
|
(!p->symbol_name && !p->addr))
|
|
goto invalid;
|
|
|
|
if (p->symbol_name) {
|
|
kprobe_lookup_name(p->symbol_name, addr);
|
|
if (!addr)
|
|
return ERR_PTR(-ENOENT);
|
|
}
|
|
|
|
addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
|
|
if (addr)
|
|
return addr;
|
|
|
|
invalid:
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
/* Check passed kprobe is valid and return kprobe in kprobe_table. */
|
|
static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *ap, *list_p;
|
|
|
|
ap = get_kprobe(p->addr);
|
|
if (unlikely(!ap))
|
|
return NULL;
|
|
|
|
if (p != ap) {
|
|
list_for_each_entry_rcu(list_p, &ap->list, list)
|
|
if (list_p == p)
|
|
/* kprobe p is a valid probe */
|
|
goto valid;
|
|
return NULL;
|
|
}
|
|
valid:
|
|
return ap;
|
|
}
|
|
|
|
/* Return error if the kprobe is being re-registered */
|
|
static inline int check_kprobe_rereg(struct kprobe *p)
|
|
{
|
|
int ret = 0;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
if (__get_valid_kprobe(p))
|
|
ret = -EINVAL;
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int __kprobes register_kprobe(struct kprobe *p)
|
|
{
|
|
int ret = 0;
|
|
struct kprobe *old_p;
|
|
struct module *probed_mod;
|
|
kprobe_opcode_t *addr;
|
|
|
|
addr = kprobe_addr(p);
|
|
if (IS_ERR(addr))
|
|
return PTR_ERR(addr);
|
|
p->addr = addr;
|
|
|
|
ret = check_kprobe_rereg(p);
|
|
if (ret)
|
|
return ret;
|
|
|
|
jump_label_lock();
|
|
preempt_disable();
|
|
if (!kernel_text_address((unsigned long) p->addr) ||
|
|
in_kprobes_functions((unsigned long) p->addr) ||
|
|
ftrace_text_reserved(p->addr, p->addr) ||
|
|
jump_label_text_reserved(p->addr, p->addr)) {
|
|
ret = -EINVAL;
|
|
goto cannot_probe;
|
|
}
|
|
|
|
/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
|
|
p->flags &= KPROBE_FLAG_DISABLED;
|
|
|
|
/*
|
|
* Check if are we probing a module.
|
|
*/
|
|
probed_mod = __module_text_address((unsigned long) p->addr);
|
|
if (probed_mod) {
|
|
/* Return -ENOENT if fail. */
|
|
ret = -ENOENT;
|
|
/*
|
|
* We must hold a refcount of the probed module while updating
|
|
* its code to prohibit unexpected unloading.
|
|
*/
|
|
if (unlikely(!try_module_get(probed_mod)))
|
|
goto cannot_probe;
|
|
|
|
/*
|
|
* If the module freed .init.text, we couldn't insert
|
|
* kprobes in there.
|
|
*/
|
|
if (within_module_init((unsigned long)p->addr, probed_mod) &&
|
|
probed_mod->state != MODULE_STATE_COMING) {
|
|
module_put(probed_mod);
|
|
goto cannot_probe;
|
|
}
|
|
/* ret will be updated by following code */
|
|
}
|
|
preempt_enable();
|
|
jump_label_unlock();
|
|
|
|
p->nmissed = 0;
|
|
INIT_LIST_HEAD(&p->list);
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
jump_label_lock(); /* needed to call jump_label_text_reserved() */
|
|
|
|
get_online_cpus(); /* For avoiding text_mutex deadlock. */
|
|
mutex_lock(&text_mutex);
|
|
|
|
old_p = get_kprobe(p->addr);
|
|
if (old_p) {
|
|
/* Since this may unoptimize old_p, locking text_mutex. */
|
|
ret = register_aggr_kprobe(old_p, p);
|
|
goto out;
|
|
}
|
|
|
|
ret = arch_prepare_kprobe(p);
|
|
if (ret)
|
|
goto out;
|
|
|
|
INIT_HLIST_NODE(&p->hlist);
|
|
hlist_add_head_rcu(&p->hlist,
|
|
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
|
|
|
|
if (!kprobes_all_disarmed && !kprobe_disabled(p))
|
|
__arm_kprobe(p);
|
|
|
|
/* Try to optimize kprobe */
|
|
try_to_optimize_kprobe(p);
|
|
|
|
out:
|
|
mutex_unlock(&text_mutex);
|
|
put_online_cpus();
|
|
jump_label_unlock();
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
if (probed_mod)
|
|
module_put(probed_mod);
|
|
|
|
return ret;
|
|
|
|
cannot_probe:
|
|
preempt_enable();
|
|
jump_label_unlock();
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kprobe);
|
|
|
|
/* Check if all probes on the aggrprobe are disabled */
|
|
static int __kprobes aggr_kprobe_disabled(struct kprobe *ap)
|
|
{
|
|
struct kprobe *kp;
|
|
|
|
list_for_each_entry_rcu(kp, &ap->list, list)
|
|
if (!kprobe_disabled(kp))
|
|
/*
|
|
* There is an active probe on the list.
|
|
* We can't disable this ap.
|
|
*/
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* Disable one kprobe: Make sure called under kprobe_mutex is locked */
|
|
static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *orig_p;
|
|
|
|
/* Get an original kprobe for return */
|
|
orig_p = __get_valid_kprobe(p);
|
|
if (unlikely(orig_p == NULL))
|
|
return NULL;
|
|
|
|
if (!kprobe_disabled(p)) {
|
|
/* Disable probe if it is a child probe */
|
|
if (p != orig_p)
|
|
p->flags |= KPROBE_FLAG_DISABLED;
|
|
|
|
/* Try to disarm and disable this/parent probe */
|
|
if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
|
|
disarm_kprobe(orig_p);
|
|
orig_p->flags |= KPROBE_FLAG_DISABLED;
|
|
}
|
|
}
|
|
|
|
return orig_p;
|
|
}
|
|
|
|
/*
|
|
* Unregister a kprobe without a scheduler synchronization.
|
|
*/
|
|
static int __kprobes __unregister_kprobe_top(struct kprobe *p)
|
|
{
|
|
struct kprobe *ap, *list_p;
|
|
|
|
/* Disable kprobe. This will disarm it if needed. */
|
|
ap = __disable_kprobe(p);
|
|
if (ap == NULL)
|
|
return -EINVAL;
|
|
|
|
if (ap == p)
|
|
/*
|
|
* This probe is an independent(and non-optimized) kprobe
|
|
* (not an aggrprobe). Remove from the hash list.
|
|
*/
|
|
goto disarmed;
|
|
|
|
/* Following process expects this probe is an aggrprobe */
|
|
WARN_ON(!kprobe_aggrprobe(ap));
|
|
|
|
if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
|
|
/*
|
|
* !disarmed could be happen if the probe is under delayed
|
|
* unoptimizing.
|
|
*/
|
|
goto disarmed;
|
|
else {
|
|
/* If disabling probe has special handlers, update aggrprobe */
|
|
if (p->break_handler && !kprobe_gone(p))
|
|
ap->break_handler = NULL;
|
|
if (p->post_handler && !kprobe_gone(p)) {
|
|
list_for_each_entry_rcu(list_p, &ap->list, list) {
|
|
if ((list_p != p) && (list_p->post_handler))
|
|
goto noclean;
|
|
}
|
|
ap->post_handler = NULL;
|
|
}
|
|
noclean:
|
|
/*
|
|
* Remove from the aggrprobe: this path will do nothing in
|
|
* __unregister_kprobe_bottom().
|
|
*/
|
|
list_del_rcu(&p->list);
|
|
if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
|
|
/*
|
|
* Try to optimize this probe again, because post
|
|
* handler may have been changed.
|
|
*/
|
|
optimize_kprobe(ap);
|
|
}
|
|
return 0;
|
|
|
|
disarmed:
|
|
BUG_ON(!kprobe_disarmed(ap));
|
|
hlist_del_rcu(&ap->hlist);
|
|
return 0;
|
|
}
|
|
|
|
static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
|
|
{
|
|
struct kprobe *ap;
|
|
|
|
if (list_empty(&p->list))
|
|
/* This is an independent kprobe */
|
|
arch_remove_kprobe(p);
|
|
else if (list_is_singular(&p->list)) {
|
|
/* This is the last child of an aggrprobe */
|
|
ap = list_entry(p->list.next, struct kprobe, list);
|
|
list_del(&p->list);
|
|
free_aggr_kprobe(ap);
|
|
}
|
|
/* Otherwise, do nothing. */
|
|
}
|
|
|
|
int __kprobes register_kprobes(struct kprobe **kps, int num)
|
|
{
|
|
int i, ret = 0;
|
|
|
|
if (num <= 0)
|
|
return -EINVAL;
|
|
for (i = 0; i < num; i++) {
|
|
ret = register_kprobe(kps[i]);
|
|
if (ret < 0) {
|
|
if (i > 0)
|
|
unregister_kprobes(kps, i);
|
|
break;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kprobes);
|
|
|
|
void __kprobes unregister_kprobe(struct kprobe *p)
|
|
{
|
|
unregister_kprobes(&p, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kprobe);
|
|
|
|
void __kprobes unregister_kprobes(struct kprobe **kps, int num)
|
|
{
|
|
int i;
|
|
|
|
if (num <= 0)
|
|
return;
|
|
mutex_lock(&kprobe_mutex);
|
|
for (i = 0; i < num; i++)
|
|
if (__unregister_kprobe_top(kps[i]) < 0)
|
|
kps[i]->addr = NULL;
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
synchronize_sched();
|
|
for (i = 0; i < num; i++)
|
|
if (kps[i]->addr)
|
|
__unregister_kprobe_bottom(kps[i]);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kprobes);
|
|
|
|
static struct notifier_block kprobe_exceptions_nb = {
|
|
.notifier_call = kprobe_exceptions_notify,
|
|
.priority = 0x7fffffff /* we need to be notified first */
|
|
};
|
|
|
|
unsigned long __weak arch_deref_entry_point(void *entry)
|
|
{
|
|
return (unsigned long)entry;
|
|
}
|
|
|
|
int __kprobes register_jprobes(struct jprobe **jps, int num)
|
|
{
|
|
struct jprobe *jp;
|
|
int ret = 0, i;
|
|
|
|
if (num <= 0)
|
|
return -EINVAL;
|
|
for (i = 0; i < num; i++) {
|
|
unsigned long addr, offset;
|
|
jp = jps[i];
|
|
addr = arch_deref_entry_point(jp->entry);
|
|
|
|
/* Verify probepoint is a function entry point */
|
|
if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
|
|
offset == 0) {
|
|
jp->kp.pre_handler = setjmp_pre_handler;
|
|
jp->kp.break_handler = longjmp_break_handler;
|
|
ret = register_kprobe(&jp->kp);
|
|
} else
|
|
ret = -EINVAL;
|
|
|
|
if (ret < 0) {
|
|
if (i > 0)
|
|
unregister_jprobes(jps, i);
|
|
break;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_jprobes);
|
|
|
|
int __kprobes register_jprobe(struct jprobe *jp)
|
|
{
|
|
return register_jprobes(&jp, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_jprobe);
|
|
|
|
void __kprobes unregister_jprobe(struct jprobe *jp)
|
|
{
|
|
unregister_jprobes(&jp, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_jprobe);
|
|
|
|
void __kprobes unregister_jprobes(struct jprobe **jps, int num)
|
|
{
|
|
int i;
|
|
|
|
if (num <= 0)
|
|
return;
|
|
mutex_lock(&kprobe_mutex);
|
|
for (i = 0; i < num; i++)
|
|
if (__unregister_kprobe_top(&jps[i]->kp) < 0)
|
|
jps[i]->kp.addr = NULL;
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
synchronize_sched();
|
|
for (i = 0; i < num; i++) {
|
|
if (jps[i]->kp.addr)
|
|
__unregister_kprobe_bottom(&jps[i]->kp);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_jprobes);
|
|
|
|
#ifdef CONFIG_KRETPROBES
|
|
/*
|
|
* This kprobe pre_handler is registered with every kretprobe. When probe
|
|
* hits it will set up the return probe.
|
|
*/
|
|
static int __kprobes pre_handler_kretprobe(struct kprobe *p,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct kretprobe *rp = container_of(p, struct kretprobe, kp);
|
|
unsigned long hash, flags = 0;
|
|
struct kretprobe_instance *ri;
|
|
|
|
/*TODO: consider to only swap the RA after the last pre_handler fired */
|
|
hash = hash_ptr(current, KPROBE_HASH_BITS);
|
|
raw_spin_lock_irqsave(&rp->lock, flags);
|
|
if (!hlist_empty(&rp->free_instances)) {
|
|
ri = hlist_entry(rp->free_instances.first,
|
|
struct kretprobe_instance, hlist);
|
|
hlist_del(&ri->hlist);
|
|
raw_spin_unlock_irqrestore(&rp->lock, flags);
|
|
|
|
ri->rp = rp;
|
|
ri->task = current;
|
|
|
|
if (rp->entry_handler && rp->entry_handler(ri, regs)) {
|
|
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;
|
|
}
|
|
|
|
int __kprobes register_kretprobe(struct kretprobe *rp)
|
|
{
|
|
int ret = 0;
|
|
struct kretprobe_instance *inst;
|
|
int i;
|
|
void *addr;
|
|
|
|
if (kretprobe_blacklist_size) {
|
|
addr = kprobe_addr(&rp->kp);
|
|
if (IS_ERR(addr))
|
|
return PTR_ERR(addr);
|
|
|
|
for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
|
|
if (kretprobe_blacklist[i].addr == addr)
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
rp->kp.pre_handler = pre_handler_kretprobe;
|
|
rp->kp.post_handler = NULL;
|
|
rp->kp.fault_handler = NULL;
|
|
rp->kp.break_handler = NULL;
|
|
|
|
/* Pre-allocate memory for max kretprobe instances */
|
|
if (rp->maxactive <= 0) {
|
|
#ifdef CONFIG_PREEMPT
|
|
rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
|
|
#else
|
|
rp->maxactive = num_possible_cpus();
|
|
#endif
|
|
}
|
|
raw_spin_lock_init(&rp->lock);
|
|
INIT_HLIST_HEAD(&rp->free_instances);
|
|
for (i = 0; i < rp->maxactive; i++) {
|
|
inst = kmalloc(sizeof(struct kretprobe_instance) +
|
|
rp->data_size, GFP_KERNEL);
|
|
if (inst == NULL) {
|
|
free_rp_inst(rp);
|
|
return -ENOMEM;
|
|
}
|
|
INIT_HLIST_NODE(&inst->hlist);
|
|
hlist_add_head(&inst->hlist, &rp->free_instances);
|
|
}
|
|
|
|
rp->nmissed = 0;
|
|
/* Establish function entry probe point */
|
|
ret = register_kprobe(&rp->kp);
|
|
if (ret != 0)
|
|
free_rp_inst(rp);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kretprobe);
|
|
|
|
int __kprobes register_kretprobes(struct kretprobe **rps, int num)
|
|
{
|
|
int ret = 0, i;
|
|
|
|
if (num <= 0)
|
|
return -EINVAL;
|
|
for (i = 0; i < num; i++) {
|
|
ret = register_kretprobe(rps[i]);
|
|
if (ret < 0) {
|
|
if (i > 0)
|
|
unregister_kretprobes(rps, i);
|
|
break;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kretprobes);
|
|
|
|
void __kprobes unregister_kretprobe(struct kretprobe *rp)
|
|
{
|
|
unregister_kretprobes(&rp, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobe);
|
|
|
|
void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
|
|
{
|
|
int i;
|
|
|
|
if (num <= 0)
|
|
return;
|
|
mutex_lock(&kprobe_mutex);
|
|
for (i = 0; i < num; i++)
|
|
if (__unregister_kprobe_top(&rps[i]->kp) < 0)
|
|
rps[i]->kp.addr = NULL;
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
synchronize_sched();
|
|
for (i = 0; i < num; i++) {
|
|
if (rps[i]->kp.addr) {
|
|
__unregister_kprobe_bottom(&rps[i]->kp);
|
|
cleanup_rp_inst(rps[i]);
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobes);
|
|
|
|
#else /* CONFIG_KRETPROBES */
|
|
int __kprobes register_kretprobe(struct kretprobe *rp)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kretprobe);
|
|
|
|
int __kprobes register_kretprobes(struct kretprobe **rps, int num)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kretprobes);
|
|
|
|
void __kprobes unregister_kretprobe(struct kretprobe *rp)
|
|
{
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobe);
|
|
|
|
void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
|
|
{
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobes);
|
|
|
|
static int __kprobes pre_handler_kretprobe(struct kprobe *p,
|
|
struct pt_regs *regs)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_KRETPROBES */
|
|
|
|
/* Set the kprobe gone and remove its instruction buffer. */
|
|
static void __kprobes kill_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *kp;
|
|
|
|
p->flags |= KPROBE_FLAG_GONE;
|
|
if (kprobe_aggrprobe(p)) {
|
|
/*
|
|
* If this is an aggr_kprobe, we have to list all the
|
|
* chained probes and mark them GONE.
|
|
*/
|
|
list_for_each_entry_rcu(kp, &p->list, list)
|
|
kp->flags |= KPROBE_FLAG_GONE;
|
|
p->post_handler = NULL;
|
|
p->break_handler = NULL;
|
|
kill_optimized_kprobe(p);
|
|
}
|
|
/*
|
|
* Here, we can remove insn_slot safely, because no thread calls
|
|
* the original probed function (which will be freed soon) any more.
|
|
*/
|
|
arch_remove_kprobe(p);
|
|
}
|
|
|
|
/* Disable one kprobe */
|
|
int __kprobes disable_kprobe(struct kprobe *kp)
|
|
{
|
|
int ret = 0;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
/* Disable this kprobe */
|
|
if (__disable_kprobe(kp) == NULL)
|
|
ret = -EINVAL;
|
|
|
|
mutex_unlock(&kprobe_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(disable_kprobe);
|
|
|
|
/* Enable one kprobe */
|
|
int __kprobes enable_kprobe(struct kprobe *kp)
|
|
{
|
|
int ret = 0;
|
|
struct kprobe *p;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
/* Check whether specified probe is valid. */
|
|
p = __get_valid_kprobe(kp);
|
|
if (unlikely(p == NULL)) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (kprobe_gone(kp)) {
|
|
/* This kprobe has gone, we couldn't enable it. */
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (p != kp)
|
|
kp->flags &= ~KPROBE_FLAG_DISABLED;
|
|
|
|
if (!kprobes_all_disarmed && kprobe_disabled(p)) {
|
|
p->flags &= ~KPROBE_FLAG_DISABLED;
|
|
arm_kprobe(p);
|
|
}
|
|
out:
|
|
mutex_unlock(&kprobe_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(enable_kprobe);
|
|
|
|
void __kprobes dump_kprobe(struct kprobe *kp)
|
|
{
|
|
printk(KERN_WARNING "Dumping kprobe:\n");
|
|
printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
|
|
kp->symbol_name, kp->addr, kp->offset);
|
|
}
|
|
|
|
/* Module notifier call back, checking kprobes on the module */
|
|
static int __kprobes kprobes_module_callback(struct notifier_block *nb,
|
|
unsigned long val, void *data)
|
|
{
|
|
struct module *mod = data;
|
|
struct hlist_head *head;
|
|
struct hlist_node *node;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
int checkcore = (val == MODULE_STATE_GOING);
|
|
|
|
if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
|
|
return NOTIFY_DONE;
|
|
|
|
/*
|
|
* When MODULE_STATE_GOING was notified, both of module .text and
|
|
* .init.text sections would be freed. When MODULE_STATE_LIVE was
|
|
* notified, only .init.text section would be freed. We need to
|
|
* disable kprobes which have been inserted in the sections.
|
|
*/
|
|
mutex_lock(&kprobe_mutex);
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, node, head, hlist)
|
|
if (within_module_init((unsigned long)p->addr, mod) ||
|
|
(checkcore &&
|
|
within_module_core((unsigned long)p->addr, mod))) {
|
|
/*
|
|
* The vaddr this probe is installed will soon
|
|
* be vfreed buy not synced to disk. Hence,
|
|
* disarming the breakpoint isn't needed.
|
|
*/
|
|
kill_kprobe(p);
|
|
}
|
|
}
|
|
mutex_unlock(&kprobe_mutex);
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block kprobe_module_nb = {
|
|
.notifier_call = kprobes_module_callback,
|
|
.priority = 0
|
|
};
|
|
|
|
static int __init init_kprobes(void)
|
|
{
|
|
int i, err = 0;
|
|
unsigned long offset = 0, size = 0;
|
|
char *modname, namebuf[128];
|
|
const char *symbol_name;
|
|
void *addr;
|
|
struct kprobe_blackpoint *kb;
|
|
|
|
/* FIXME allocate the probe table, currently defined statically */
|
|
/* initialize all list heads */
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
INIT_HLIST_HEAD(&kprobe_table[i]);
|
|
INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
|
|
raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
|
|
}
|
|
|
|
/*
|
|
* Lookup and populate the kprobe_blacklist.
|
|
*
|
|
* Unlike the kretprobe blacklist, we'll need to determine
|
|
* the range of addresses that belong to the said functions,
|
|
* since a kprobe need not necessarily be at the beginning
|
|
* of a function.
|
|
*/
|
|
for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
|
|
kprobe_lookup_name(kb->name, addr);
|
|
if (!addr)
|
|
continue;
|
|
|
|
kb->start_addr = (unsigned long)addr;
|
|
symbol_name = kallsyms_lookup(kb->start_addr,
|
|
&size, &offset, &modname, namebuf);
|
|
if (!symbol_name)
|
|
kb->range = 0;
|
|
else
|
|
kb->range = size;
|
|
}
|
|
|
|
if (kretprobe_blacklist_size) {
|
|
/* lookup the function address from its name */
|
|
for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
|
|
kprobe_lookup_name(kretprobe_blacklist[i].name,
|
|
kretprobe_blacklist[i].addr);
|
|
if (!kretprobe_blacklist[i].addr)
|
|
printk("kretprobe: lookup failed: %s\n",
|
|
kretprobe_blacklist[i].name);
|
|
}
|
|
}
|
|
|
|
#if defined(CONFIG_OPTPROBES)
|
|
#if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
|
|
/* Init kprobe_optinsn_slots */
|
|
kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
|
|
#endif
|
|
/* By default, kprobes can be optimized */
|
|
kprobes_allow_optimization = true;
|
|
#endif
|
|
|
|
/* By default, kprobes are armed */
|
|
kprobes_all_disarmed = false;
|
|
|
|
err = arch_init_kprobes();
|
|
if (!err)
|
|
err = register_die_notifier(&kprobe_exceptions_nb);
|
|
if (!err)
|
|
err = register_module_notifier(&kprobe_module_nb);
|
|
|
|
kprobes_initialized = (err == 0);
|
|
|
|
if (!err)
|
|
init_test_probes();
|
|
return err;
|
|
}
|
|
|
|
#ifdef CONFIG_DEBUG_FS
|
|
static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
|
|
const char *sym, int offset, char *modname, struct kprobe *pp)
|
|
{
|
|
char *kprobe_type;
|
|
|
|
if (p->pre_handler == pre_handler_kretprobe)
|
|
kprobe_type = "r";
|
|
else if (p->pre_handler == setjmp_pre_handler)
|
|
kprobe_type = "j";
|
|
else
|
|
kprobe_type = "k";
|
|
|
|
if (sym)
|
|
seq_printf(pi, "%p %s %s+0x%x %s ",
|
|
p->addr, kprobe_type, sym, offset,
|
|
(modname ? modname : " "));
|
|
else
|
|
seq_printf(pi, "%p %s %p ",
|
|
p->addr, kprobe_type, p->addr);
|
|
|
|
if (!pp)
|
|
pp = p;
|
|
seq_printf(pi, "%s%s%s\n",
|
|
(kprobe_gone(p) ? "[GONE]" : ""),
|
|
((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
|
|
(kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
|
|
}
|
|
|
|
static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
|
|
{
|
|
return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
|
|
}
|
|
|
|
static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
|
|
{
|
|
(*pos)++;
|
|
if (*pos >= KPROBE_TABLE_SIZE)
|
|
return NULL;
|
|
return pos;
|
|
}
|
|
|
|
static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
|
|
{
|
|
/* Nothing to do */
|
|
}
|
|
|
|
static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node;
|
|
struct kprobe *p, *kp;
|
|
const char *sym = NULL;
|
|
unsigned int i = *(loff_t *) v;
|
|
unsigned long offset = 0;
|
|
char *modname, namebuf[128];
|
|
|
|
head = &kprobe_table[i];
|
|
preempt_disable();
|
|
hlist_for_each_entry_rcu(p, node, head, hlist) {
|
|
sym = kallsyms_lookup((unsigned long)p->addr, NULL,
|
|
&offset, &modname, namebuf);
|
|
if (kprobe_aggrprobe(p)) {
|
|
list_for_each_entry_rcu(kp, &p->list, list)
|
|
report_probe(pi, kp, sym, offset, modname, p);
|
|
} else
|
|
report_probe(pi, p, sym, offset, modname, NULL);
|
|
}
|
|
preempt_enable();
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations kprobes_seq_ops = {
|
|
.start = kprobe_seq_start,
|
|
.next = kprobe_seq_next,
|
|
.stop = kprobe_seq_stop,
|
|
.show = show_kprobe_addr
|
|
};
|
|
|
|
static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
|
|
{
|
|
return seq_open(filp, &kprobes_seq_ops);
|
|
}
|
|
|
|
static const struct file_operations debugfs_kprobes_operations = {
|
|
.open = kprobes_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release,
|
|
};
|
|
|
|
static void __kprobes arm_all_kprobes(void)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
/* If kprobes are armed, just return */
|
|
if (!kprobes_all_disarmed)
|
|
goto already_enabled;
|
|
|
|
/* Arming kprobes doesn't optimize kprobe itself */
|
|
mutex_lock(&text_mutex);
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, node, head, hlist)
|
|
if (!kprobe_disabled(p))
|
|
__arm_kprobe(p);
|
|
}
|
|
mutex_unlock(&text_mutex);
|
|
|
|
kprobes_all_disarmed = false;
|
|
printk(KERN_INFO "Kprobes globally enabled\n");
|
|
|
|
already_enabled:
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
|
|
static void __kprobes disarm_all_kprobes(void)
|
|
{
|
|
struct hlist_head *head;
|
|
struct hlist_node *node;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
/* If kprobes are already disarmed, just return */
|
|
if (kprobes_all_disarmed) {
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
|
|
kprobes_all_disarmed = true;
|
|
printk(KERN_INFO "Kprobes globally disabled\n");
|
|
|
|
mutex_lock(&text_mutex);
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, node, head, hlist) {
|
|
if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
|
|
__disarm_kprobe(p, false);
|
|
}
|
|
}
|
|
mutex_unlock(&text_mutex);
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
/* Wait for disarming all kprobes by optimizer */
|
|
wait_for_kprobe_optimizer();
|
|
}
|
|
|
|
/*
|
|
* XXX: The debugfs bool file interface doesn't allow for callbacks
|
|
* when the bool state is switched. We can reuse that facility when
|
|
* available
|
|
*/
|
|
static ssize_t read_enabled_file_bool(struct file *file,
|
|
char __user *user_buf, size_t count, loff_t *ppos)
|
|
{
|
|
char buf[3];
|
|
|
|
if (!kprobes_all_disarmed)
|
|
buf[0] = '1';
|
|
else
|
|
buf[0] = '0';
|
|
buf[1] = '\n';
|
|
buf[2] = 0x00;
|
|
return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
|
|
}
|
|
|
|
static ssize_t write_enabled_file_bool(struct file *file,
|
|
const char __user *user_buf, size_t count, loff_t *ppos)
|
|
{
|
|
char buf[32];
|
|
size_t buf_size;
|
|
|
|
buf_size = min(count, (sizeof(buf)-1));
|
|
if (copy_from_user(buf, user_buf, buf_size))
|
|
return -EFAULT;
|
|
|
|
switch (buf[0]) {
|
|
case 'y':
|
|
case 'Y':
|
|
case '1':
|
|
arm_all_kprobes();
|
|
break;
|
|
case 'n':
|
|
case 'N':
|
|
case '0':
|
|
disarm_all_kprobes();
|
|
break;
|
|
}
|
|
|
|
return count;
|
|
}
|
|
|
|
static const struct file_operations fops_kp = {
|
|
.read = read_enabled_file_bool,
|
|
.write = write_enabled_file_bool,
|
|
.llseek = default_llseek,
|
|
};
|
|
|
|
static int __kprobes debugfs_kprobe_init(void)
|
|
{
|
|
struct dentry *dir, *file;
|
|
unsigned int value = 1;
|
|
|
|
dir = debugfs_create_dir("kprobes", NULL);
|
|
if (!dir)
|
|
return -ENOMEM;
|
|
|
|
file = debugfs_create_file("list", 0444, dir, NULL,
|
|
&debugfs_kprobes_operations);
|
|
if (!file) {
|
|
debugfs_remove(dir);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
file = debugfs_create_file("enabled", 0600, dir,
|
|
&value, &fops_kp);
|
|
if (!file) {
|
|
debugfs_remove(dir);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
late_initcall(debugfs_kprobe_init);
|
|
#endif /* CONFIG_DEBUG_FS */
|
|
|
|
module_init(init_kprobes);
|
|
|
|
/* defined in arch/.../kernel/kprobes.c */
|
|
EXPORT_SYMBOL_GPL(jprobe_return);
|