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e5779e8e12
Code on the kprobe blacklist doesn't want unexpected int3 exceptions. It probably doesn't want unexpected debug exceptions either. Be safe: disallow breakpoints in nokprobes code. On non-CONFIG_KPROBES kernels, there is no kprobe blacklist. In that case, disallow kernel breakpoints entirely. It will be particularly important to keep hw breakpoints out of the entry and NMI code once we move debug exceptions off the IST stack. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/e14b152af99640448d895e3c2a8c2d5ee19a1325.1438312874.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2473 lines
61 KiB
C
2473 lines
61 KiB
C
/*
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* Kernel Probes (KProbes)
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* kernel/kprobes.c
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) IBM Corporation, 2002, 2004
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*
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* 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
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* Probes initial implementation (includes suggestions from
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* Rusty Russell).
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* 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
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* hlists and exceptions notifier as suggested by Andi Kleen.
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* 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
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* interface to access function arguments.
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* 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
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* exceptions notifier to be first on the priority list.
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* 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
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* <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
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* <prasanna@in.ibm.com> added function-return probes.
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*/
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#include <linux/kprobes.h>
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#include <linux/hash.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/stddef.h>
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#include <linux/export.h>
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#include <linux/moduleloader.h>
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#include <linux/kallsyms.h>
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#include <linux/freezer.h>
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#include <linux/seq_file.h>
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#include <linux/debugfs.h>
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#include <linux/sysctl.h>
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#include <linux/kdebug.h>
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#include <linux/memory.h>
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#include <linux/ftrace.h>
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#include <linux/cpu.h>
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#include <linux/jump_label.h>
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#include <asm-generic/sections.h>
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#include <asm/cacheflush.h>
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#include <asm/errno.h>
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#include <asm/uaccess.h>
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#define KPROBE_HASH_BITS 6
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#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
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/*
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* Some oddball architectures like 64bit powerpc have function descriptors
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* so this must be overridable.
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*/
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#ifndef kprobe_lookup_name
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#define kprobe_lookup_name(name, addr) \
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addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
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#endif
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static int kprobes_initialized;
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static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
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static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
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/* NOTE: change this value only with kprobe_mutex held */
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static bool kprobes_all_disarmed;
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/* This protects kprobe_table and optimizing_list */
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static DEFINE_MUTEX(kprobe_mutex);
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static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
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static struct {
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raw_spinlock_t lock ____cacheline_aligned_in_smp;
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} kretprobe_table_locks[KPROBE_TABLE_SIZE];
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static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
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{
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return &(kretprobe_table_locks[hash].lock);
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}
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/* Blacklist -- list of struct kprobe_blacklist_entry */
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static LIST_HEAD(kprobe_blacklist);
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#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
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/*
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* kprobe->ainsn.insn points to the copy of the instruction to be
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* single-stepped. x86_64, POWER4 and above have no-exec support and
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* stepping on the instruction on a vmalloced/kmalloced/data page
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* is a recipe for disaster
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*/
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struct kprobe_insn_page {
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struct list_head list;
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kprobe_opcode_t *insns; /* Page of instruction slots */
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struct kprobe_insn_cache *cache;
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int nused;
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int ngarbage;
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char slot_used[];
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};
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#define KPROBE_INSN_PAGE_SIZE(slots) \
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(offsetof(struct kprobe_insn_page, slot_used) + \
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(sizeof(char) * (slots)))
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static int slots_per_page(struct kprobe_insn_cache *c)
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{
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return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
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}
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enum kprobe_slot_state {
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SLOT_CLEAN = 0,
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SLOT_DIRTY = 1,
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SLOT_USED = 2,
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};
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static void *alloc_insn_page(void)
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{
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return module_alloc(PAGE_SIZE);
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}
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static void free_insn_page(void *page)
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{
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module_memfree(page);
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}
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struct kprobe_insn_cache kprobe_insn_slots = {
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.mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
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.alloc = alloc_insn_page,
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.free = free_insn_page,
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.pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
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.insn_size = MAX_INSN_SIZE,
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.nr_garbage = 0,
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};
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static int collect_garbage_slots(struct kprobe_insn_cache *c);
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/**
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* __get_insn_slot() - Find a slot on an executable page for an instruction.
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* We allocate an executable page if there's no room on existing ones.
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*/
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kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
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{
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struct kprobe_insn_page *kip;
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kprobe_opcode_t *slot = NULL;
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mutex_lock(&c->mutex);
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retry:
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list_for_each_entry(kip, &c->pages, list) {
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if (kip->nused < slots_per_page(c)) {
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int i;
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for (i = 0; i < slots_per_page(c); i++) {
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if (kip->slot_used[i] == SLOT_CLEAN) {
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kip->slot_used[i] = SLOT_USED;
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kip->nused++;
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slot = kip->insns + (i * c->insn_size);
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goto out;
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}
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}
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/* kip->nused is broken. Fix it. */
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kip->nused = slots_per_page(c);
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WARN_ON(1);
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}
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}
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/* If there are any garbage slots, collect it and try again. */
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if (c->nr_garbage && collect_garbage_slots(c) == 0)
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goto retry;
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/* All out of space. Need to allocate a new page. */
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kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
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if (!kip)
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goto out;
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/*
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* Use module_alloc so this page is within +/- 2GB of where the
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* kernel image and loaded module images reside. This is required
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* so x86_64 can correctly handle the %rip-relative fixups.
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*/
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kip->insns = c->alloc();
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if (!kip->insns) {
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kfree(kip);
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goto out;
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}
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INIT_LIST_HEAD(&kip->list);
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memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
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kip->slot_used[0] = SLOT_USED;
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kip->nused = 1;
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kip->ngarbage = 0;
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kip->cache = c;
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list_add(&kip->list, &c->pages);
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slot = kip->insns;
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out:
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mutex_unlock(&c->mutex);
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return slot;
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}
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/* Return 1 if all garbages are collected, otherwise 0. */
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static int collect_one_slot(struct kprobe_insn_page *kip, int idx)
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{
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kip->slot_used[idx] = SLOT_CLEAN;
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kip->nused--;
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if (kip->nused == 0) {
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/*
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* Page is no longer in use. Free it unless
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* it's the last one. We keep the last one
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* so as not to have to set it up again the
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* next time somebody inserts a probe.
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*/
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if (!list_is_singular(&kip->list)) {
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list_del(&kip->list);
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kip->cache->free(kip->insns);
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kfree(kip);
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}
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return 1;
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}
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return 0;
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}
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static int collect_garbage_slots(struct kprobe_insn_cache *c)
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{
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struct kprobe_insn_page *kip, *next;
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/* Ensure no-one is interrupted on the garbages */
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synchronize_sched();
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list_for_each_entry_safe(kip, next, &c->pages, list) {
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int i;
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if (kip->ngarbage == 0)
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continue;
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kip->ngarbage = 0; /* we will collect all garbages */
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for (i = 0; i < slots_per_page(c); i++) {
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if (kip->slot_used[i] == SLOT_DIRTY &&
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collect_one_slot(kip, i))
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break;
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}
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}
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c->nr_garbage = 0;
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return 0;
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}
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void __free_insn_slot(struct kprobe_insn_cache *c,
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kprobe_opcode_t *slot, int dirty)
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{
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struct kprobe_insn_page *kip;
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mutex_lock(&c->mutex);
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list_for_each_entry(kip, &c->pages, list) {
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long idx = ((long)slot - (long)kip->insns) /
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(c->insn_size * sizeof(kprobe_opcode_t));
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if (idx >= 0 && idx < slots_per_page(c)) {
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WARN_ON(kip->slot_used[idx] != SLOT_USED);
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if (dirty) {
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kip->slot_used[idx] = SLOT_DIRTY;
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kip->ngarbage++;
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if (++c->nr_garbage > slots_per_page(c))
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collect_garbage_slots(c);
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} else
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collect_one_slot(kip, idx);
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goto out;
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}
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}
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/* Could not free this slot. */
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WARN_ON(1);
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out:
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mutex_unlock(&c->mutex);
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}
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#ifdef CONFIG_OPTPROBES
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/* For optimized_kprobe buffer */
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struct kprobe_insn_cache kprobe_optinsn_slots = {
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.mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
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.alloc = alloc_insn_page,
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.free = free_insn_page,
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.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
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/* .insn_size is initialized later */
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.nr_garbage = 0,
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};
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#endif
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#endif
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/* We have preemption disabled.. so it is safe to use __ versions */
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static inline void set_kprobe_instance(struct kprobe *kp)
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{
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__this_cpu_write(kprobe_instance, kp);
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}
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static inline void reset_kprobe_instance(void)
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{
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__this_cpu_write(kprobe_instance, NULL);
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}
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/*
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* This routine is called either:
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* - under the kprobe_mutex - during kprobe_[un]register()
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* OR
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* - with preemption disabled - from arch/xxx/kernel/kprobes.c
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*/
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struct kprobe *get_kprobe(void *addr)
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{
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struct hlist_head *head;
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struct kprobe *p;
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head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
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hlist_for_each_entry_rcu(p, head, hlist) {
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if (p->addr == addr)
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return p;
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}
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return NULL;
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}
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NOKPROBE_SYMBOL(get_kprobe);
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static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
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/* Return true if the kprobe is an aggregator */
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static inline int kprobe_aggrprobe(struct kprobe *p)
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{
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return p->pre_handler == aggr_pre_handler;
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}
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/* Return true(!0) if the kprobe is unused */
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static inline int kprobe_unused(struct kprobe *p)
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{
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return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
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list_empty(&p->list);
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}
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/*
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* Keep all fields in the kprobe consistent
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*/
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static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
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{
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memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
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memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
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}
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#ifdef CONFIG_OPTPROBES
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/* NOTE: change this value only with kprobe_mutex held */
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static bool kprobes_allow_optimization;
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/*
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* Call all pre_handler on the list, but ignores its return value.
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* This must be called from arch-dep optimized caller.
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*/
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void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
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{
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struct kprobe *kp;
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list_for_each_entry_rcu(kp, &p->list, list) {
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if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
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set_kprobe_instance(kp);
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kp->pre_handler(kp, regs);
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}
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reset_kprobe_instance();
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}
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}
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NOKPROBE_SYMBOL(opt_pre_handler);
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/* Free optimized instructions and optimized_kprobe */
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static void free_aggr_kprobe(struct kprobe *p)
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{
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struct optimized_kprobe *op;
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op = container_of(p, struct optimized_kprobe, kp);
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arch_remove_optimized_kprobe(op);
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arch_remove_kprobe(p);
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kfree(op);
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}
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/* Return true(!0) if the kprobe is ready for optimization. */
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static inline int kprobe_optready(struct kprobe *p)
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{
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struct optimized_kprobe *op;
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if (kprobe_aggrprobe(p)) {
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op = container_of(p, struct optimized_kprobe, kp);
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return arch_prepared_optinsn(&op->optinsn);
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}
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return 0;
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}
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/* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
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static inline int kprobe_disarmed(struct kprobe *p)
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{
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struct optimized_kprobe *op;
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/* If kprobe is not aggr/opt probe, just return kprobe is disabled */
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if (!kprobe_aggrprobe(p))
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return kprobe_disabled(p);
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op = container_of(p, struct optimized_kprobe, kp);
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return kprobe_disabled(p) && list_empty(&op->list);
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}
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/* Return true(!0) if the probe is queued on (un)optimizing lists */
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static int kprobe_queued(struct kprobe *p)
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{
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struct optimized_kprobe *op;
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if (kprobe_aggrprobe(p)) {
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op = container_of(p, struct optimized_kprobe, kp);
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if (!list_empty(&op->list))
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return 1;
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}
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return 0;
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}
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/*
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* Return an optimized kprobe whose optimizing code replaces
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* instructions including addr (exclude breakpoint).
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*/
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static struct kprobe *get_optimized_kprobe(unsigned long addr)
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{
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int i;
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struct kprobe *p = NULL;
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struct optimized_kprobe *op;
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/* Don't check i == 0, since that is a breakpoint case. */
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for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
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p = get_kprobe((void *)(addr - i));
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if (p && kprobe_optready(p)) {
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op = container_of(p, struct optimized_kprobe, kp);
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if (arch_within_optimized_kprobe(op, addr))
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return p;
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}
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return NULL;
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}
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/* Optimization staging list, protected by kprobe_mutex */
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static LIST_HEAD(optimizing_list);
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static LIST_HEAD(unoptimizing_list);
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static LIST_HEAD(freeing_list);
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static void kprobe_optimizer(struct work_struct *work);
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static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
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#define OPTIMIZE_DELAY 5
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|
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/*
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* Optimize (replace a breakpoint with a jump) kprobes listed on
|
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* optimizing_list.
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*/
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static void do_optimize_kprobes(void)
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{
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/* Optimization never be done when disarmed */
|
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if (kprobes_all_disarmed || !kprobes_allow_optimization ||
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list_empty(&optimizing_list))
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return;
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|
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/*
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* The optimization/unoptimization refers online_cpus via
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* stop_machine() and cpu-hotplug modifies online_cpus.
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* And same time, text_mutex will be held in cpu-hotplug and here.
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* This combination can cause a deadlock (cpu-hotplug try to lock
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* text_mutex but stop_machine can not be done because online_cpus
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* has been changed)
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* To avoid this deadlock, we need to call get_online_cpus()
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* for preventing cpu-hotplug outside of text_mutex locking.
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*/
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get_online_cpus();
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mutex_lock(&text_mutex);
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arch_optimize_kprobes(&optimizing_list);
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mutex_unlock(&text_mutex);
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put_online_cpus();
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}
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/*
|
|
* Unoptimize (replace a jump with a breakpoint and remove the breakpoint
|
|
* if need) kprobes listed on unoptimizing_list.
|
|
*/
|
|
static void do_unoptimize_kprobes(void)
|
|
{
|
|
struct optimized_kprobe *op, *tmp;
|
|
|
|
/* Unoptimization must be done anytime */
|
|
if (list_empty(&unoptimizing_list))
|
|
return;
|
|
|
|
/* Ditto to do_optimize_kprobes */
|
|
get_online_cpus();
|
|
mutex_lock(&text_mutex);
|
|
arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
|
|
/* Loop free_list for disarming */
|
|
list_for_each_entry_safe(op, tmp, &freeing_list, list) {
|
|
/* Disarm probes if marked disabled */
|
|
if (kprobe_disabled(&op->kp))
|
|
arch_disarm_kprobe(&op->kp);
|
|
if (kprobe_unused(&op->kp)) {
|
|
/*
|
|
* Remove unused probes from hash list. After waiting
|
|
* for synchronization, these probes are reclaimed.
|
|
* (reclaiming is done by do_free_cleaned_kprobes.)
|
|
*/
|
|
hlist_del_rcu(&op->kp.hlist);
|
|
} else
|
|
list_del_init(&op->list);
|
|
}
|
|
mutex_unlock(&text_mutex);
|
|
put_online_cpus();
|
|
}
|
|
|
|
/* Reclaim all kprobes on the free_list */
|
|
static void do_free_cleaned_kprobes(void)
|
|
{
|
|
struct optimized_kprobe *op, *tmp;
|
|
|
|
list_for_each_entry_safe(op, tmp, &freeing_list, list) {
|
|
BUG_ON(!kprobe_unused(&op->kp));
|
|
list_del_init(&op->list);
|
|
free_aggr_kprobe(&op->kp);
|
|
}
|
|
}
|
|
|
|
/* Start optimizer after OPTIMIZE_DELAY passed */
|
|
static void kick_kprobe_optimizer(void)
|
|
{
|
|
schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
|
|
}
|
|
|
|
/* Kprobe jump optimizer */
|
|
static void kprobe_optimizer(struct work_struct *work)
|
|
{
|
|
mutex_lock(&kprobe_mutex);
|
|
/* Lock modules while optimizing kprobes */
|
|
mutex_lock(&module_mutex);
|
|
|
|
/*
|
|
* Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
|
|
* kprobes before waiting for quiesence period.
|
|
*/
|
|
do_unoptimize_kprobes();
|
|
|
|
/*
|
|
* Step 2: Wait for quiesence period to ensure all running interrupts
|
|
* are done. Because optprobe may modify multiple instructions
|
|
* there is a chance that Nth instruction is interrupted. In that
|
|
* case, running interrupt can return to 2nd-Nth byte of jump
|
|
* instruction. This wait is for avoiding it.
|
|
*/
|
|
synchronize_sched();
|
|
|
|
/* Step 3: Optimize kprobes after quiesence period */
|
|
do_optimize_kprobes();
|
|
|
|
/* Step 4: Free cleaned kprobes after quiesence period */
|
|
do_free_cleaned_kprobes();
|
|
|
|
mutex_unlock(&module_mutex);
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
/* Step 5: Kick optimizer again if needed */
|
|
if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
|
|
kick_kprobe_optimizer();
|
|
}
|
|
|
|
/* Wait for completing optimization and unoptimization */
|
|
static void wait_for_kprobe_optimizer(void)
|
|
{
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) {
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
/* this will also make optimizing_work execute immmediately */
|
|
flush_delayed_work(&optimizing_work);
|
|
/* @optimizing_work might not have been queued yet, relax */
|
|
cpu_relax();
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
}
|
|
|
|
mutex_unlock(&kprobe_mutex);
|
|
}
|
|
|
|
/* Optimize kprobe if p is ready to be optimized */
|
|
static void optimize_kprobe(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
/* Check if the kprobe is disabled or not ready for optimization. */
|
|
if (!kprobe_optready(p) || !kprobes_allow_optimization ||
|
|
(kprobe_disabled(p) || kprobes_all_disarmed))
|
|
return;
|
|
|
|
/* Both of break_handler and post_handler are not supported. */
|
|
if (p->break_handler || p->post_handler)
|
|
return;
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
|
|
/* Check there is no other kprobes at the optimized instructions */
|
|
if (arch_check_optimized_kprobe(op) < 0)
|
|
return;
|
|
|
|
/* Check if it is already optimized. */
|
|
if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
|
|
return;
|
|
op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
|
|
|
|
if (!list_empty(&op->list))
|
|
/* This is under unoptimizing. Just dequeue the probe */
|
|
list_del_init(&op->list);
|
|
else {
|
|
list_add(&op->list, &optimizing_list);
|
|
kick_kprobe_optimizer();
|
|
}
|
|
}
|
|
|
|
/* Short cut to direct unoptimizing */
|
|
static void force_unoptimize_kprobe(struct optimized_kprobe *op)
|
|
{
|
|
get_online_cpus();
|
|
arch_unoptimize_kprobe(op);
|
|
put_online_cpus();
|
|
if (kprobe_disabled(&op->kp))
|
|
arch_disarm_kprobe(&op->kp);
|
|
}
|
|
|
|
/* Unoptimize a kprobe if p is optimized */
|
|
static void unoptimize_kprobe(struct kprobe *p, bool force)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
|
|
return; /* This is not an optprobe nor optimized */
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
if (!kprobe_optimized(p)) {
|
|
/* Unoptimized or unoptimizing case */
|
|
if (force && !list_empty(&op->list)) {
|
|
/*
|
|
* Only if this is unoptimizing kprobe and forced,
|
|
* forcibly unoptimize it. (No need to unoptimize
|
|
* unoptimized kprobe again :)
|
|
*/
|
|
list_del_init(&op->list);
|
|
force_unoptimize_kprobe(op);
|
|
}
|
|
return;
|
|
}
|
|
|
|
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
|
|
if (!list_empty(&op->list)) {
|
|
/* Dequeue from the optimization queue */
|
|
list_del_init(&op->list);
|
|
return;
|
|
}
|
|
/* Optimized kprobe case */
|
|
if (force)
|
|
/* Forcibly update the code: this is a special case */
|
|
force_unoptimize_kprobe(op);
|
|
else {
|
|
list_add(&op->list, &unoptimizing_list);
|
|
kick_kprobe_optimizer();
|
|
}
|
|
}
|
|
|
|
/* Cancel unoptimizing for reusing */
|
|
static void reuse_unused_kprobe(struct kprobe *ap)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
BUG_ON(!kprobe_unused(ap));
|
|
/*
|
|
* Unused kprobe MUST be on the way of delayed unoptimizing (means
|
|
* there is still a relative jump) and disabled.
|
|
*/
|
|
op = container_of(ap, struct optimized_kprobe, kp);
|
|
if (unlikely(list_empty(&op->list)))
|
|
printk(KERN_WARNING "Warning: found a stray unused "
|
|
"aggrprobe@%p\n", ap->addr);
|
|
/* Enable the probe again */
|
|
ap->flags &= ~KPROBE_FLAG_DISABLED;
|
|
/* Optimize it again (remove from op->list) */
|
|
BUG_ON(!kprobe_optready(ap));
|
|
optimize_kprobe(ap);
|
|
}
|
|
|
|
/* Remove optimized instructions */
|
|
static void kill_optimized_kprobe(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
if (!list_empty(&op->list))
|
|
/* Dequeue from the (un)optimization queue */
|
|
list_del_init(&op->list);
|
|
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
|
|
|
|
if (kprobe_unused(p)) {
|
|
/* Enqueue if it is unused */
|
|
list_add(&op->list, &freeing_list);
|
|
/*
|
|
* Remove unused probes from the hash list. After waiting
|
|
* for synchronization, this probe is reclaimed.
|
|
* (reclaiming is done by do_free_cleaned_kprobes().)
|
|
*/
|
|
hlist_del_rcu(&op->kp.hlist);
|
|
}
|
|
|
|
/* Don't touch the code, because it is already freed. */
|
|
arch_remove_optimized_kprobe(op);
|
|
}
|
|
|
|
/* Try to prepare optimized instructions */
|
|
static void prepare_optimized_kprobe(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
op = container_of(p, struct optimized_kprobe, kp);
|
|
arch_prepare_optimized_kprobe(op, p);
|
|
}
|
|
|
|
/* Allocate new optimized_kprobe and try to prepare optimized instructions */
|
|
static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
|
|
{
|
|
struct optimized_kprobe *op;
|
|
|
|
op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
|
|
if (!op)
|
|
return NULL;
|
|
|
|
INIT_LIST_HEAD(&op->list);
|
|
op->kp.addr = p->addr;
|
|
arch_prepare_optimized_kprobe(op, p);
|
|
|
|
return &op->kp;
|
|
}
|
|
|
|
static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
|
|
|
|
/*
|
|
* Prepare an optimized_kprobe and optimize it
|
|
* NOTE: p must be a normal registered kprobe
|
|
*/
|
|
static void try_to_optimize_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *ap;
|
|
struct optimized_kprobe *op;
|
|
|
|
/* Impossible to optimize ftrace-based kprobe */
|
|
if (kprobe_ftrace(p))
|
|
return;
|
|
|
|
/* For preparing optimization, jump_label_text_reserved() is called */
|
|
jump_label_lock();
|
|
mutex_lock(&text_mutex);
|
|
|
|
ap = alloc_aggr_kprobe(p);
|
|
if (!ap)
|
|
goto out;
|
|
|
|
op = container_of(ap, struct optimized_kprobe, kp);
|
|
if (!arch_prepared_optinsn(&op->optinsn)) {
|
|
/* If failed to setup optimizing, fallback to kprobe */
|
|
arch_remove_optimized_kprobe(op);
|
|
kfree(op);
|
|
goto out;
|
|
}
|
|
|
|
init_aggr_kprobe(ap, p);
|
|
optimize_kprobe(ap); /* This just kicks optimizer thread */
|
|
|
|
out:
|
|
mutex_unlock(&text_mutex);
|
|
jump_label_unlock();
|
|
}
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
static void optimize_all_kprobes(void)
|
|
{
|
|
struct hlist_head *head;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
/* If optimization is already allowed, just return */
|
|
if (kprobes_allow_optimization)
|
|
goto out;
|
|
|
|
kprobes_allow_optimization = true;
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, head, hlist)
|
|
if (!kprobe_disabled(p))
|
|
optimize_kprobe(p);
|
|
}
|
|
printk(KERN_INFO "Kprobes globally optimized\n");
|
|
out:
|
|
mutex_unlock(&kprobe_mutex);
|
|
}
|
|
|
|
static void unoptimize_all_kprobes(void)
|
|
{
|
|
struct hlist_head *head;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
/* If optimization is already prohibited, just return */
|
|
if (!kprobes_allow_optimization) {
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
|
|
kprobes_allow_optimization = false;
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, head, hlist) {
|
|
if (!kprobe_disabled(p))
|
|
unoptimize_kprobe(p, false);
|
|
}
|
|
}
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
/* Wait for unoptimizing completion */
|
|
wait_for_kprobe_optimizer();
|
|
printk(KERN_INFO "Kprobes globally unoptimized\n");
|
|
}
|
|
|
|
static DEFINE_MUTEX(kprobe_sysctl_mutex);
|
|
int sysctl_kprobes_optimization;
|
|
int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
|
|
void __user *buffer, size_t *length,
|
|
loff_t *ppos)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&kprobe_sysctl_mutex);
|
|
sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
|
|
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
|
|
|
|
if (sysctl_kprobes_optimization)
|
|
optimize_all_kprobes();
|
|
else
|
|
unoptimize_all_kprobes();
|
|
mutex_unlock(&kprobe_sysctl_mutex);
|
|
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_SYSCTL */
|
|
|
|
/* Put a breakpoint for a probe. Must be called with text_mutex locked */
|
|
static void __arm_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *_p;
|
|
|
|
/* Check collision with other optimized kprobes */
|
|
_p = get_optimized_kprobe((unsigned long)p->addr);
|
|
if (unlikely(_p))
|
|
/* Fallback to unoptimized kprobe */
|
|
unoptimize_kprobe(_p, true);
|
|
|
|
arch_arm_kprobe(p);
|
|
optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
|
|
}
|
|
|
|
/* Remove the breakpoint of a probe. Must be called with text_mutex locked */
|
|
static void __disarm_kprobe(struct kprobe *p, bool reopt)
|
|
{
|
|
struct kprobe *_p;
|
|
|
|
/* Try to unoptimize */
|
|
unoptimize_kprobe(p, kprobes_all_disarmed);
|
|
|
|
if (!kprobe_queued(p)) {
|
|
arch_disarm_kprobe(p);
|
|
/* If another kprobe was blocked, optimize it. */
|
|
_p = get_optimized_kprobe((unsigned long)p->addr);
|
|
if (unlikely(_p) && reopt)
|
|
optimize_kprobe(_p);
|
|
}
|
|
/* TODO: reoptimize others after unoptimized this probe */
|
|
}
|
|
|
|
#else /* !CONFIG_OPTPROBES */
|
|
|
|
#define optimize_kprobe(p) do {} while (0)
|
|
#define unoptimize_kprobe(p, f) do {} while (0)
|
|
#define kill_optimized_kprobe(p) do {} while (0)
|
|
#define prepare_optimized_kprobe(p) do {} while (0)
|
|
#define try_to_optimize_kprobe(p) do {} while (0)
|
|
#define __arm_kprobe(p) arch_arm_kprobe(p)
|
|
#define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
|
|
#define kprobe_disarmed(p) kprobe_disabled(p)
|
|
#define wait_for_kprobe_optimizer() do {} while (0)
|
|
|
|
/* There should be no unused kprobes can be reused without optimization */
|
|
static void reuse_unused_kprobe(struct kprobe *ap)
|
|
{
|
|
printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
|
|
BUG_ON(kprobe_unused(ap));
|
|
}
|
|
|
|
static void free_aggr_kprobe(struct kprobe *p)
|
|
{
|
|
arch_remove_kprobe(p);
|
|
kfree(p);
|
|
}
|
|
|
|
static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
|
|
{
|
|
return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
|
|
}
|
|
#endif /* CONFIG_OPTPROBES */
|
|
|
|
#ifdef CONFIG_KPROBES_ON_FTRACE
|
|
static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
|
|
.func = kprobe_ftrace_handler,
|
|
.flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
|
|
};
|
|
static int kprobe_ftrace_enabled;
|
|
|
|
/* Must ensure p->addr is really on ftrace */
|
|
static int prepare_kprobe(struct kprobe *p)
|
|
{
|
|
if (!kprobe_ftrace(p))
|
|
return arch_prepare_kprobe(p);
|
|
|
|
return arch_prepare_kprobe_ftrace(p);
|
|
}
|
|
|
|
/* Caller must lock kprobe_mutex */
|
|
static void arm_kprobe_ftrace(struct kprobe *p)
|
|
{
|
|
int ret;
|
|
|
|
ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
|
|
(unsigned long)p->addr, 0, 0);
|
|
WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret);
|
|
kprobe_ftrace_enabled++;
|
|
if (kprobe_ftrace_enabled == 1) {
|
|
ret = register_ftrace_function(&kprobe_ftrace_ops);
|
|
WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
|
|
}
|
|
}
|
|
|
|
/* Caller must lock kprobe_mutex */
|
|
static void disarm_kprobe_ftrace(struct kprobe *p)
|
|
{
|
|
int ret;
|
|
|
|
kprobe_ftrace_enabled--;
|
|
if (kprobe_ftrace_enabled == 0) {
|
|
ret = unregister_ftrace_function(&kprobe_ftrace_ops);
|
|
WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
|
|
}
|
|
ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
|
|
(unsigned long)p->addr, 1, 0);
|
|
WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
|
|
}
|
|
#else /* !CONFIG_KPROBES_ON_FTRACE */
|
|
#define prepare_kprobe(p) arch_prepare_kprobe(p)
|
|
#define arm_kprobe_ftrace(p) do {} while (0)
|
|
#define disarm_kprobe_ftrace(p) do {} while (0)
|
|
#endif
|
|
|
|
/* Arm a kprobe with text_mutex */
|
|
static void arm_kprobe(struct kprobe *kp)
|
|
{
|
|
if (unlikely(kprobe_ftrace(kp))) {
|
|
arm_kprobe_ftrace(kp);
|
|
return;
|
|
}
|
|
/*
|
|
* Here, since __arm_kprobe() doesn't use stop_machine(),
|
|
* this doesn't cause deadlock on text_mutex. So, we don't
|
|
* need get_online_cpus().
|
|
*/
|
|
mutex_lock(&text_mutex);
|
|
__arm_kprobe(kp);
|
|
mutex_unlock(&text_mutex);
|
|
}
|
|
|
|
/* Disarm a kprobe with text_mutex */
|
|
static void disarm_kprobe(struct kprobe *kp, bool reopt)
|
|
{
|
|
if (unlikely(kprobe_ftrace(kp))) {
|
|
disarm_kprobe_ftrace(kp);
|
|
return;
|
|
}
|
|
/* Ditto */
|
|
mutex_lock(&text_mutex);
|
|
__disarm_kprobe(kp, reopt);
|
|
mutex_unlock(&text_mutex);
|
|
}
|
|
|
|
/*
|
|
* Aggregate handlers for multiple kprobes support - these handlers
|
|
* take care of invoking the individual kprobe handlers on p->list
|
|
*/
|
|
static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct kprobe *kp;
|
|
|
|
list_for_each_entry_rcu(kp, &p->list, list) {
|
|
if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
|
|
set_kprobe_instance(kp);
|
|
if (kp->pre_handler(kp, regs))
|
|
return 1;
|
|
}
|
|
reset_kprobe_instance();
|
|
}
|
|
return 0;
|
|
}
|
|
NOKPROBE_SYMBOL(aggr_pre_handler);
|
|
|
|
static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
|
|
unsigned long flags)
|
|
{
|
|
struct kprobe *kp;
|
|
|
|
list_for_each_entry_rcu(kp, &p->list, list) {
|
|
if (kp->post_handler && likely(!kprobe_disabled(kp))) {
|
|
set_kprobe_instance(kp);
|
|
kp->post_handler(kp, regs, flags);
|
|
reset_kprobe_instance();
|
|
}
|
|
}
|
|
}
|
|
NOKPROBE_SYMBOL(aggr_post_handler);
|
|
|
|
static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
|
|
int trapnr)
|
|
{
|
|
struct kprobe *cur = __this_cpu_read(kprobe_instance);
|
|
|
|
/*
|
|
* if we faulted "during" the execution of a user specified
|
|
* probe handler, invoke just that probe's fault handler
|
|
*/
|
|
if (cur && cur->fault_handler) {
|
|
if (cur->fault_handler(cur, regs, trapnr))
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
NOKPROBE_SYMBOL(aggr_fault_handler);
|
|
|
|
static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct kprobe *cur = __this_cpu_read(kprobe_instance);
|
|
int ret = 0;
|
|
|
|
if (cur && cur->break_handler) {
|
|
if (cur->break_handler(cur, regs))
|
|
ret = 1;
|
|
}
|
|
reset_kprobe_instance();
|
|
return ret;
|
|
}
|
|
NOKPROBE_SYMBOL(aggr_break_handler);
|
|
|
|
/* Walks the list and increments nmissed count for multiprobe case */
|
|
void kprobes_inc_nmissed_count(struct kprobe *p)
|
|
{
|
|
struct kprobe *kp;
|
|
if (!kprobe_aggrprobe(p)) {
|
|
p->nmissed++;
|
|
} else {
|
|
list_for_each_entry_rcu(kp, &p->list, list)
|
|
kp->nmissed++;
|
|
}
|
|
return;
|
|
}
|
|
NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
|
|
|
|
void recycle_rp_inst(struct kretprobe_instance *ri,
|
|
struct hlist_head *head)
|
|
{
|
|
struct kretprobe *rp = ri->rp;
|
|
|
|
/* remove rp inst off the rprobe_inst_table */
|
|
hlist_del(&ri->hlist);
|
|
INIT_HLIST_NODE(&ri->hlist);
|
|
if (likely(rp)) {
|
|
raw_spin_lock(&rp->lock);
|
|
hlist_add_head(&ri->hlist, &rp->free_instances);
|
|
raw_spin_unlock(&rp->lock);
|
|
} else
|
|
/* Unregistering */
|
|
hlist_add_head(&ri->hlist, head);
|
|
}
|
|
NOKPROBE_SYMBOL(recycle_rp_inst);
|
|
|
|
void kretprobe_hash_lock(struct task_struct *tsk,
|
|
struct hlist_head **head, unsigned long *flags)
|
|
__acquires(hlist_lock)
|
|
{
|
|
unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
|
|
raw_spinlock_t *hlist_lock;
|
|
|
|
*head = &kretprobe_inst_table[hash];
|
|
hlist_lock = kretprobe_table_lock_ptr(hash);
|
|
raw_spin_lock_irqsave(hlist_lock, *flags);
|
|
}
|
|
NOKPROBE_SYMBOL(kretprobe_hash_lock);
|
|
|
|
static void kretprobe_table_lock(unsigned long hash,
|
|
unsigned long *flags)
|
|
__acquires(hlist_lock)
|
|
{
|
|
raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
|
|
raw_spin_lock_irqsave(hlist_lock, *flags);
|
|
}
|
|
NOKPROBE_SYMBOL(kretprobe_table_lock);
|
|
|
|
void kretprobe_hash_unlock(struct task_struct *tsk,
|
|
unsigned long *flags)
|
|
__releases(hlist_lock)
|
|
{
|
|
unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
|
|
raw_spinlock_t *hlist_lock;
|
|
|
|
hlist_lock = kretprobe_table_lock_ptr(hash);
|
|
raw_spin_unlock_irqrestore(hlist_lock, *flags);
|
|
}
|
|
NOKPROBE_SYMBOL(kretprobe_hash_unlock);
|
|
|
|
static void kretprobe_table_unlock(unsigned long hash,
|
|
unsigned long *flags)
|
|
__releases(hlist_lock)
|
|
{
|
|
raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
|
|
raw_spin_unlock_irqrestore(hlist_lock, *flags);
|
|
}
|
|
NOKPROBE_SYMBOL(kretprobe_table_unlock);
|
|
|
|
/*
|
|
* This function is called from finish_task_switch when task tk becomes dead,
|
|
* so that we can recycle any function-return probe instances associated
|
|
* with this task. These left over instances represent probed functions
|
|
* that have been called but will never return.
|
|
*/
|
|
void kprobe_flush_task(struct task_struct *tk)
|
|
{
|
|
struct kretprobe_instance *ri;
|
|
struct hlist_head *head, empty_rp;
|
|
struct hlist_node *tmp;
|
|
unsigned long hash, flags = 0;
|
|
|
|
if (unlikely(!kprobes_initialized))
|
|
/* Early boot. kretprobe_table_locks not yet initialized. */
|
|
return;
|
|
|
|
INIT_HLIST_HEAD(&empty_rp);
|
|
hash = hash_ptr(tk, KPROBE_HASH_BITS);
|
|
head = &kretprobe_inst_table[hash];
|
|
kretprobe_table_lock(hash, &flags);
|
|
hlist_for_each_entry_safe(ri, tmp, head, hlist) {
|
|
if (ri->task == tk)
|
|
recycle_rp_inst(ri, &empty_rp);
|
|
}
|
|
kretprobe_table_unlock(hash, &flags);
|
|
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
|
|
hlist_del(&ri->hlist);
|
|
kfree(ri);
|
|
}
|
|
}
|
|
NOKPROBE_SYMBOL(kprobe_flush_task);
|
|
|
|
static inline void free_rp_inst(struct kretprobe *rp)
|
|
{
|
|
struct kretprobe_instance *ri;
|
|
struct hlist_node *next;
|
|
|
|
hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) {
|
|
hlist_del(&ri->hlist);
|
|
kfree(ri);
|
|
}
|
|
}
|
|
|
|
static void cleanup_rp_inst(struct kretprobe *rp)
|
|
{
|
|
unsigned long flags, hash;
|
|
struct kretprobe_instance *ri;
|
|
struct hlist_node *next;
|
|
struct hlist_head *head;
|
|
|
|
/* No race here */
|
|
for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
|
|
kretprobe_table_lock(hash, &flags);
|
|
head = &kretprobe_inst_table[hash];
|
|
hlist_for_each_entry_safe(ri, next, head, hlist) {
|
|
if (ri->rp == rp)
|
|
ri->rp = NULL;
|
|
}
|
|
kretprobe_table_unlock(hash, &flags);
|
|
}
|
|
free_rp_inst(rp);
|
|
}
|
|
NOKPROBE_SYMBOL(cleanup_rp_inst);
|
|
|
|
/*
|
|
* Add the new probe to ap->list. Fail if this is the
|
|
* second jprobe at the address - two jprobes can't coexist
|
|
*/
|
|
static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
|
|
{
|
|
BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
|
|
|
|
if (p->break_handler || p->post_handler)
|
|
unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
|
|
|
|
if (p->break_handler) {
|
|
if (ap->break_handler)
|
|
return -EEXIST;
|
|
list_add_tail_rcu(&p->list, &ap->list);
|
|
ap->break_handler = aggr_break_handler;
|
|
} else
|
|
list_add_rcu(&p->list, &ap->list);
|
|
if (p->post_handler && !ap->post_handler)
|
|
ap->post_handler = aggr_post_handler;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Fill in the required fields of the "manager kprobe". Replace the
|
|
* earlier kprobe in the hlist with the manager kprobe
|
|
*/
|
|
static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
|
|
{
|
|
/* Copy p's insn slot to ap */
|
|
copy_kprobe(p, ap);
|
|
flush_insn_slot(ap);
|
|
ap->addr = p->addr;
|
|
ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
|
|
ap->pre_handler = aggr_pre_handler;
|
|
ap->fault_handler = aggr_fault_handler;
|
|
/* We don't care the kprobe which has gone. */
|
|
if (p->post_handler && !kprobe_gone(p))
|
|
ap->post_handler = aggr_post_handler;
|
|
if (p->break_handler && !kprobe_gone(p))
|
|
ap->break_handler = aggr_break_handler;
|
|
|
|
INIT_LIST_HEAD(&ap->list);
|
|
INIT_HLIST_NODE(&ap->hlist);
|
|
|
|
list_add_rcu(&p->list, &ap->list);
|
|
hlist_replace_rcu(&p->hlist, &ap->hlist);
|
|
}
|
|
|
|
/*
|
|
* This is the second or subsequent kprobe at the address - handle
|
|
* the intricacies
|
|
*/
|
|
static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
|
|
{
|
|
int ret = 0;
|
|
struct kprobe *ap = orig_p;
|
|
|
|
/* For preparing optimization, jump_label_text_reserved() is called */
|
|
jump_label_lock();
|
|
/*
|
|
* Get online CPUs to avoid text_mutex deadlock.with stop machine,
|
|
* which is invoked by unoptimize_kprobe() in add_new_kprobe()
|
|
*/
|
|
get_online_cpus();
|
|
mutex_lock(&text_mutex);
|
|
|
|
if (!kprobe_aggrprobe(orig_p)) {
|
|
/* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
|
|
ap = alloc_aggr_kprobe(orig_p);
|
|
if (!ap) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
init_aggr_kprobe(ap, orig_p);
|
|
} else if (kprobe_unused(ap))
|
|
/* This probe is going to die. Rescue it */
|
|
reuse_unused_kprobe(ap);
|
|
|
|
if (kprobe_gone(ap)) {
|
|
/*
|
|
* Attempting to insert new probe at the same location that
|
|
* had a probe in the module vaddr area which already
|
|
* freed. So, the instruction slot has already been
|
|
* released. We need a new slot for the new probe.
|
|
*/
|
|
ret = arch_prepare_kprobe(ap);
|
|
if (ret)
|
|
/*
|
|
* Even if fail to allocate new slot, don't need to
|
|
* free aggr_probe. It will be used next time, or
|
|
* freed by unregister_kprobe.
|
|
*/
|
|
goto out;
|
|
|
|
/* Prepare optimized instructions if possible. */
|
|
prepare_optimized_kprobe(ap);
|
|
|
|
/*
|
|
* Clear gone flag to prevent allocating new slot again, and
|
|
* set disabled flag because it is not armed yet.
|
|
*/
|
|
ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
|
|
| KPROBE_FLAG_DISABLED;
|
|
}
|
|
|
|
/* Copy ap's insn slot to p */
|
|
copy_kprobe(ap, p);
|
|
ret = add_new_kprobe(ap, p);
|
|
|
|
out:
|
|
mutex_unlock(&text_mutex);
|
|
put_online_cpus();
|
|
jump_label_unlock();
|
|
|
|
if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
|
|
ap->flags &= ~KPROBE_FLAG_DISABLED;
|
|
if (!kprobes_all_disarmed)
|
|
/* Arm the breakpoint again. */
|
|
arm_kprobe(ap);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
bool __weak arch_within_kprobe_blacklist(unsigned long addr)
|
|
{
|
|
/* The __kprobes marked functions and entry code must not be probed */
|
|
return addr >= (unsigned long)__kprobes_text_start &&
|
|
addr < (unsigned long)__kprobes_text_end;
|
|
}
|
|
|
|
bool within_kprobe_blacklist(unsigned long addr)
|
|
{
|
|
struct kprobe_blacklist_entry *ent;
|
|
|
|
if (arch_within_kprobe_blacklist(addr))
|
|
return true;
|
|
/*
|
|
* If there exists a kprobe_blacklist, verify and
|
|
* fail any probe registration in the prohibited area
|
|
*/
|
|
list_for_each_entry(ent, &kprobe_blacklist, list) {
|
|
if (addr >= ent->start_addr && addr < ent->end_addr)
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* If we have a symbol_name argument, look it up and add the offset field
|
|
* to it. This way, we can specify a relative address to a symbol.
|
|
* This returns encoded errors if it fails to look up symbol or invalid
|
|
* combination of parameters.
|
|
*/
|
|
static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
|
|
{
|
|
kprobe_opcode_t *addr = p->addr;
|
|
|
|
if ((p->symbol_name && p->addr) ||
|
|
(!p->symbol_name && !p->addr))
|
|
goto invalid;
|
|
|
|
if (p->symbol_name) {
|
|
kprobe_lookup_name(p->symbol_name, addr);
|
|
if (!addr)
|
|
return ERR_PTR(-ENOENT);
|
|
}
|
|
|
|
addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
|
|
if (addr)
|
|
return addr;
|
|
|
|
invalid:
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
/* Check passed kprobe is valid and return kprobe in kprobe_table. */
|
|
static struct kprobe *__get_valid_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *ap, *list_p;
|
|
|
|
ap = get_kprobe(p->addr);
|
|
if (unlikely(!ap))
|
|
return NULL;
|
|
|
|
if (p != ap) {
|
|
list_for_each_entry_rcu(list_p, &ap->list, list)
|
|
if (list_p == p)
|
|
/* kprobe p is a valid probe */
|
|
goto valid;
|
|
return NULL;
|
|
}
|
|
valid:
|
|
return ap;
|
|
}
|
|
|
|
/* Return error if the kprobe is being re-registered */
|
|
static inline int check_kprobe_rereg(struct kprobe *p)
|
|
{
|
|
int ret = 0;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
if (__get_valid_kprobe(p))
|
|
ret = -EINVAL;
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int __weak arch_check_ftrace_location(struct kprobe *p)
|
|
{
|
|
unsigned long ftrace_addr;
|
|
|
|
ftrace_addr = ftrace_location((unsigned long)p->addr);
|
|
if (ftrace_addr) {
|
|
#ifdef CONFIG_KPROBES_ON_FTRACE
|
|
/* Given address is not on the instruction boundary */
|
|
if ((unsigned long)p->addr != ftrace_addr)
|
|
return -EILSEQ;
|
|
p->flags |= KPROBE_FLAG_FTRACE;
|
|
#else /* !CONFIG_KPROBES_ON_FTRACE */
|
|
return -EINVAL;
|
|
#endif
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int check_kprobe_address_safe(struct kprobe *p,
|
|
struct module **probed_mod)
|
|
{
|
|
int ret;
|
|
|
|
ret = arch_check_ftrace_location(p);
|
|
if (ret)
|
|
return ret;
|
|
jump_label_lock();
|
|
preempt_disable();
|
|
|
|
/* Ensure it is not in reserved area nor out of text */
|
|
if (!kernel_text_address((unsigned long) p->addr) ||
|
|
within_kprobe_blacklist((unsigned long) p->addr) ||
|
|
jump_label_text_reserved(p->addr, p->addr)) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* Check if are we probing a module */
|
|
*probed_mod = __module_text_address((unsigned long) p->addr);
|
|
if (*probed_mod) {
|
|
/*
|
|
* We must hold a refcount of the probed module while updating
|
|
* its code to prohibit unexpected unloading.
|
|
*/
|
|
if (unlikely(!try_module_get(*probed_mod))) {
|
|
ret = -ENOENT;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* If the module freed .init.text, we couldn't insert
|
|
* kprobes in there.
|
|
*/
|
|
if (within_module_init((unsigned long)p->addr, *probed_mod) &&
|
|
(*probed_mod)->state != MODULE_STATE_COMING) {
|
|
module_put(*probed_mod);
|
|
*probed_mod = NULL;
|
|
ret = -ENOENT;
|
|
}
|
|
}
|
|
out:
|
|
preempt_enable();
|
|
jump_label_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
int register_kprobe(struct kprobe *p)
|
|
{
|
|
int ret;
|
|
struct kprobe *old_p;
|
|
struct module *probed_mod;
|
|
kprobe_opcode_t *addr;
|
|
|
|
/* Adjust probe address from symbol */
|
|
addr = kprobe_addr(p);
|
|
if (IS_ERR(addr))
|
|
return PTR_ERR(addr);
|
|
p->addr = addr;
|
|
|
|
ret = check_kprobe_rereg(p);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
|
|
p->flags &= KPROBE_FLAG_DISABLED;
|
|
p->nmissed = 0;
|
|
INIT_LIST_HEAD(&p->list);
|
|
|
|
ret = check_kprobe_address_safe(p, &probed_mod);
|
|
if (ret)
|
|
return ret;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
old_p = get_kprobe(p->addr);
|
|
if (old_p) {
|
|
/* Since this may unoptimize old_p, locking text_mutex. */
|
|
ret = register_aggr_kprobe(old_p, p);
|
|
goto out;
|
|
}
|
|
|
|
mutex_lock(&text_mutex); /* Avoiding text modification */
|
|
ret = prepare_kprobe(p);
|
|
mutex_unlock(&text_mutex);
|
|
if (ret)
|
|
goto out;
|
|
|
|
INIT_HLIST_NODE(&p->hlist);
|
|
hlist_add_head_rcu(&p->hlist,
|
|
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
|
|
|
|
if (!kprobes_all_disarmed && !kprobe_disabled(p))
|
|
arm_kprobe(p);
|
|
|
|
/* Try to optimize kprobe */
|
|
try_to_optimize_kprobe(p);
|
|
|
|
out:
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
if (probed_mod)
|
|
module_put(probed_mod);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kprobe);
|
|
|
|
/* Check if all probes on the aggrprobe are disabled */
|
|
static int aggr_kprobe_disabled(struct kprobe *ap)
|
|
{
|
|
struct kprobe *kp;
|
|
|
|
list_for_each_entry_rcu(kp, &ap->list, list)
|
|
if (!kprobe_disabled(kp))
|
|
/*
|
|
* There is an active probe on the list.
|
|
* We can't disable this ap.
|
|
*/
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* Disable one kprobe: Make sure called under kprobe_mutex is locked */
|
|
static struct kprobe *__disable_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *orig_p;
|
|
|
|
/* Get an original kprobe for return */
|
|
orig_p = __get_valid_kprobe(p);
|
|
if (unlikely(orig_p == NULL))
|
|
return NULL;
|
|
|
|
if (!kprobe_disabled(p)) {
|
|
/* Disable probe if it is a child probe */
|
|
if (p != orig_p)
|
|
p->flags |= KPROBE_FLAG_DISABLED;
|
|
|
|
/* Try to disarm and disable this/parent probe */
|
|
if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
|
|
/*
|
|
* If kprobes_all_disarmed is set, orig_p
|
|
* should have already been disarmed, so
|
|
* skip unneed disarming process.
|
|
*/
|
|
if (!kprobes_all_disarmed)
|
|
disarm_kprobe(orig_p, true);
|
|
orig_p->flags |= KPROBE_FLAG_DISABLED;
|
|
}
|
|
}
|
|
|
|
return orig_p;
|
|
}
|
|
|
|
/*
|
|
* Unregister a kprobe without a scheduler synchronization.
|
|
*/
|
|
static int __unregister_kprobe_top(struct kprobe *p)
|
|
{
|
|
struct kprobe *ap, *list_p;
|
|
|
|
/* Disable kprobe. This will disarm it if needed. */
|
|
ap = __disable_kprobe(p);
|
|
if (ap == NULL)
|
|
return -EINVAL;
|
|
|
|
if (ap == p)
|
|
/*
|
|
* This probe is an independent(and non-optimized) kprobe
|
|
* (not an aggrprobe). Remove from the hash list.
|
|
*/
|
|
goto disarmed;
|
|
|
|
/* Following process expects this probe is an aggrprobe */
|
|
WARN_ON(!kprobe_aggrprobe(ap));
|
|
|
|
if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
|
|
/*
|
|
* !disarmed could be happen if the probe is under delayed
|
|
* unoptimizing.
|
|
*/
|
|
goto disarmed;
|
|
else {
|
|
/* If disabling probe has special handlers, update aggrprobe */
|
|
if (p->break_handler && !kprobe_gone(p))
|
|
ap->break_handler = NULL;
|
|
if (p->post_handler && !kprobe_gone(p)) {
|
|
list_for_each_entry_rcu(list_p, &ap->list, list) {
|
|
if ((list_p != p) && (list_p->post_handler))
|
|
goto noclean;
|
|
}
|
|
ap->post_handler = NULL;
|
|
}
|
|
noclean:
|
|
/*
|
|
* Remove from the aggrprobe: this path will do nothing in
|
|
* __unregister_kprobe_bottom().
|
|
*/
|
|
list_del_rcu(&p->list);
|
|
if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
|
|
/*
|
|
* Try to optimize this probe again, because post
|
|
* handler may have been changed.
|
|
*/
|
|
optimize_kprobe(ap);
|
|
}
|
|
return 0;
|
|
|
|
disarmed:
|
|
BUG_ON(!kprobe_disarmed(ap));
|
|
hlist_del_rcu(&ap->hlist);
|
|
return 0;
|
|
}
|
|
|
|
static void __unregister_kprobe_bottom(struct kprobe *p)
|
|
{
|
|
struct kprobe *ap;
|
|
|
|
if (list_empty(&p->list))
|
|
/* This is an independent kprobe */
|
|
arch_remove_kprobe(p);
|
|
else if (list_is_singular(&p->list)) {
|
|
/* This is the last child of an aggrprobe */
|
|
ap = list_entry(p->list.next, struct kprobe, list);
|
|
list_del(&p->list);
|
|
free_aggr_kprobe(ap);
|
|
}
|
|
/* Otherwise, do nothing. */
|
|
}
|
|
|
|
int register_kprobes(struct kprobe **kps, int num)
|
|
{
|
|
int i, ret = 0;
|
|
|
|
if (num <= 0)
|
|
return -EINVAL;
|
|
for (i = 0; i < num; i++) {
|
|
ret = register_kprobe(kps[i]);
|
|
if (ret < 0) {
|
|
if (i > 0)
|
|
unregister_kprobes(kps, i);
|
|
break;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kprobes);
|
|
|
|
void unregister_kprobe(struct kprobe *p)
|
|
{
|
|
unregister_kprobes(&p, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kprobe);
|
|
|
|
void unregister_kprobes(struct kprobe **kps, int num)
|
|
{
|
|
int i;
|
|
|
|
if (num <= 0)
|
|
return;
|
|
mutex_lock(&kprobe_mutex);
|
|
for (i = 0; i < num; i++)
|
|
if (__unregister_kprobe_top(kps[i]) < 0)
|
|
kps[i]->addr = NULL;
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
synchronize_sched();
|
|
for (i = 0; i < num; i++)
|
|
if (kps[i]->addr)
|
|
__unregister_kprobe_bottom(kps[i]);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kprobes);
|
|
|
|
static struct notifier_block kprobe_exceptions_nb = {
|
|
.notifier_call = kprobe_exceptions_notify,
|
|
.priority = 0x7fffffff /* we need to be notified first */
|
|
};
|
|
|
|
unsigned long __weak arch_deref_entry_point(void *entry)
|
|
{
|
|
return (unsigned long)entry;
|
|
}
|
|
|
|
int register_jprobes(struct jprobe **jps, int num)
|
|
{
|
|
struct jprobe *jp;
|
|
int ret = 0, i;
|
|
|
|
if (num <= 0)
|
|
return -EINVAL;
|
|
for (i = 0; i < num; i++) {
|
|
unsigned long addr, offset;
|
|
jp = jps[i];
|
|
addr = arch_deref_entry_point(jp->entry);
|
|
|
|
/* Verify probepoint is a function entry point */
|
|
if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
|
|
offset == 0) {
|
|
jp->kp.pre_handler = setjmp_pre_handler;
|
|
jp->kp.break_handler = longjmp_break_handler;
|
|
ret = register_kprobe(&jp->kp);
|
|
} else
|
|
ret = -EINVAL;
|
|
|
|
if (ret < 0) {
|
|
if (i > 0)
|
|
unregister_jprobes(jps, i);
|
|
break;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_jprobes);
|
|
|
|
int register_jprobe(struct jprobe *jp)
|
|
{
|
|
return register_jprobes(&jp, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_jprobe);
|
|
|
|
void unregister_jprobe(struct jprobe *jp)
|
|
{
|
|
unregister_jprobes(&jp, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_jprobe);
|
|
|
|
void unregister_jprobes(struct jprobe **jps, int num)
|
|
{
|
|
int i;
|
|
|
|
if (num <= 0)
|
|
return;
|
|
mutex_lock(&kprobe_mutex);
|
|
for (i = 0; i < num; i++)
|
|
if (__unregister_kprobe_top(&jps[i]->kp) < 0)
|
|
jps[i]->kp.addr = NULL;
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
synchronize_sched();
|
|
for (i = 0; i < num; i++) {
|
|
if (jps[i]->kp.addr)
|
|
__unregister_kprobe_bottom(&jps[i]->kp);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_jprobes);
|
|
|
|
#ifdef CONFIG_KRETPROBES
|
|
/*
|
|
* This kprobe pre_handler is registered with every kretprobe. When probe
|
|
* hits it will set up the return probe.
|
|
*/
|
|
static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct kretprobe *rp = container_of(p, struct kretprobe, kp);
|
|
unsigned long hash, flags = 0;
|
|
struct kretprobe_instance *ri;
|
|
|
|
/*
|
|
* To avoid deadlocks, prohibit return probing in NMI contexts,
|
|
* just skip the probe and increase the (inexact) 'nmissed'
|
|
* statistical counter, so that the user is informed that
|
|
* something happened:
|
|
*/
|
|
if (unlikely(in_nmi())) {
|
|
rp->nmissed++;
|
|
return 0;
|
|
}
|
|
|
|
/* TODO: consider to only swap the RA after the last pre_handler fired */
|
|
hash = hash_ptr(current, KPROBE_HASH_BITS);
|
|
raw_spin_lock_irqsave(&rp->lock, flags);
|
|
if (!hlist_empty(&rp->free_instances)) {
|
|
ri = hlist_entry(rp->free_instances.first,
|
|
struct kretprobe_instance, hlist);
|
|
hlist_del(&ri->hlist);
|
|
raw_spin_unlock_irqrestore(&rp->lock, flags);
|
|
|
|
ri->rp = rp;
|
|
ri->task = current;
|
|
|
|
if (rp->entry_handler && rp->entry_handler(ri, regs)) {
|
|
raw_spin_lock_irqsave(&rp->lock, flags);
|
|
hlist_add_head(&ri->hlist, &rp->free_instances);
|
|
raw_spin_unlock_irqrestore(&rp->lock, flags);
|
|
return 0;
|
|
}
|
|
|
|
arch_prepare_kretprobe(ri, regs);
|
|
|
|
/* XXX(hch): why is there no hlist_move_head? */
|
|
INIT_HLIST_NODE(&ri->hlist);
|
|
kretprobe_table_lock(hash, &flags);
|
|
hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
|
|
kretprobe_table_unlock(hash, &flags);
|
|
} else {
|
|
rp->nmissed++;
|
|
raw_spin_unlock_irqrestore(&rp->lock, flags);
|
|
}
|
|
return 0;
|
|
}
|
|
NOKPROBE_SYMBOL(pre_handler_kretprobe);
|
|
|
|
int register_kretprobe(struct kretprobe *rp)
|
|
{
|
|
int ret = 0;
|
|
struct kretprobe_instance *inst;
|
|
int i;
|
|
void *addr;
|
|
|
|
if (kretprobe_blacklist_size) {
|
|
addr = kprobe_addr(&rp->kp);
|
|
if (IS_ERR(addr))
|
|
return PTR_ERR(addr);
|
|
|
|
for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
|
|
if (kretprobe_blacklist[i].addr == addr)
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
rp->kp.pre_handler = pre_handler_kretprobe;
|
|
rp->kp.post_handler = NULL;
|
|
rp->kp.fault_handler = NULL;
|
|
rp->kp.break_handler = NULL;
|
|
|
|
/* Pre-allocate memory for max kretprobe instances */
|
|
if (rp->maxactive <= 0) {
|
|
#ifdef CONFIG_PREEMPT
|
|
rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
|
|
#else
|
|
rp->maxactive = num_possible_cpus();
|
|
#endif
|
|
}
|
|
raw_spin_lock_init(&rp->lock);
|
|
INIT_HLIST_HEAD(&rp->free_instances);
|
|
for (i = 0; i < rp->maxactive; i++) {
|
|
inst = kmalloc(sizeof(struct kretprobe_instance) +
|
|
rp->data_size, GFP_KERNEL);
|
|
if (inst == NULL) {
|
|
free_rp_inst(rp);
|
|
return -ENOMEM;
|
|
}
|
|
INIT_HLIST_NODE(&inst->hlist);
|
|
hlist_add_head(&inst->hlist, &rp->free_instances);
|
|
}
|
|
|
|
rp->nmissed = 0;
|
|
/* Establish function entry probe point */
|
|
ret = register_kprobe(&rp->kp);
|
|
if (ret != 0)
|
|
free_rp_inst(rp);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kretprobe);
|
|
|
|
int register_kretprobes(struct kretprobe **rps, int num)
|
|
{
|
|
int ret = 0, i;
|
|
|
|
if (num <= 0)
|
|
return -EINVAL;
|
|
for (i = 0; i < num; i++) {
|
|
ret = register_kretprobe(rps[i]);
|
|
if (ret < 0) {
|
|
if (i > 0)
|
|
unregister_kretprobes(rps, i);
|
|
break;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kretprobes);
|
|
|
|
void unregister_kretprobe(struct kretprobe *rp)
|
|
{
|
|
unregister_kretprobes(&rp, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobe);
|
|
|
|
void unregister_kretprobes(struct kretprobe **rps, int num)
|
|
{
|
|
int i;
|
|
|
|
if (num <= 0)
|
|
return;
|
|
mutex_lock(&kprobe_mutex);
|
|
for (i = 0; i < num; i++)
|
|
if (__unregister_kprobe_top(&rps[i]->kp) < 0)
|
|
rps[i]->kp.addr = NULL;
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
synchronize_sched();
|
|
for (i = 0; i < num; i++) {
|
|
if (rps[i]->kp.addr) {
|
|
__unregister_kprobe_bottom(&rps[i]->kp);
|
|
cleanup_rp_inst(rps[i]);
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobes);
|
|
|
|
#else /* CONFIG_KRETPROBES */
|
|
int register_kretprobe(struct kretprobe *rp)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kretprobe);
|
|
|
|
int register_kretprobes(struct kretprobe **rps, int num)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_kretprobes);
|
|
|
|
void unregister_kretprobe(struct kretprobe *rp)
|
|
{
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobe);
|
|
|
|
void unregister_kretprobes(struct kretprobe **rps, int num)
|
|
{
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobes);
|
|
|
|
static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
return 0;
|
|
}
|
|
NOKPROBE_SYMBOL(pre_handler_kretprobe);
|
|
|
|
#endif /* CONFIG_KRETPROBES */
|
|
|
|
/* Set the kprobe gone and remove its instruction buffer. */
|
|
static void kill_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *kp;
|
|
|
|
p->flags |= KPROBE_FLAG_GONE;
|
|
if (kprobe_aggrprobe(p)) {
|
|
/*
|
|
* If this is an aggr_kprobe, we have to list all the
|
|
* chained probes and mark them GONE.
|
|
*/
|
|
list_for_each_entry_rcu(kp, &p->list, list)
|
|
kp->flags |= KPROBE_FLAG_GONE;
|
|
p->post_handler = NULL;
|
|
p->break_handler = NULL;
|
|
kill_optimized_kprobe(p);
|
|
}
|
|
/*
|
|
* Here, we can remove insn_slot safely, because no thread calls
|
|
* the original probed function (which will be freed soon) any more.
|
|
*/
|
|
arch_remove_kprobe(p);
|
|
}
|
|
|
|
/* Disable one kprobe */
|
|
int disable_kprobe(struct kprobe *kp)
|
|
{
|
|
int ret = 0;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
/* Disable this kprobe */
|
|
if (__disable_kprobe(kp) == NULL)
|
|
ret = -EINVAL;
|
|
|
|
mutex_unlock(&kprobe_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(disable_kprobe);
|
|
|
|
/* Enable one kprobe */
|
|
int enable_kprobe(struct kprobe *kp)
|
|
{
|
|
int ret = 0;
|
|
struct kprobe *p;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
/* Check whether specified probe is valid. */
|
|
p = __get_valid_kprobe(kp);
|
|
if (unlikely(p == NULL)) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (kprobe_gone(kp)) {
|
|
/* This kprobe has gone, we couldn't enable it. */
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (p != kp)
|
|
kp->flags &= ~KPROBE_FLAG_DISABLED;
|
|
|
|
if (!kprobes_all_disarmed && kprobe_disabled(p)) {
|
|
p->flags &= ~KPROBE_FLAG_DISABLED;
|
|
arm_kprobe(p);
|
|
}
|
|
out:
|
|
mutex_unlock(&kprobe_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(enable_kprobe);
|
|
|
|
void dump_kprobe(struct kprobe *kp)
|
|
{
|
|
printk(KERN_WARNING "Dumping kprobe:\n");
|
|
printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
|
|
kp->symbol_name, kp->addr, kp->offset);
|
|
}
|
|
NOKPROBE_SYMBOL(dump_kprobe);
|
|
|
|
/*
|
|
* Lookup and populate the kprobe_blacklist.
|
|
*
|
|
* Unlike the kretprobe blacklist, we'll need to determine
|
|
* the range of addresses that belong to the said functions,
|
|
* since a kprobe need not necessarily be at the beginning
|
|
* of a function.
|
|
*/
|
|
static int __init populate_kprobe_blacklist(unsigned long *start,
|
|
unsigned long *end)
|
|
{
|
|
unsigned long *iter;
|
|
struct kprobe_blacklist_entry *ent;
|
|
unsigned long entry, offset = 0, size = 0;
|
|
|
|
for (iter = start; iter < end; iter++) {
|
|
entry = arch_deref_entry_point((void *)*iter);
|
|
|
|
if (!kernel_text_address(entry) ||
|
|
!kallsyms_lookup_size_offset(entry, &size, &offset)) {
|
|
pr_err("Failed to find blacklist at %p\n",
|
|
(void *)entry);
|
|
continue;
|
|
}
|
|
|
|
ent = kmalloc(sizeof(*ent), GFP_KERNEL);
|
|
if (!ent)
|
|
return -ENOMEM;
|
|
ent->start_addr = entry;
|
|
ent->end_addr = entry + size;
|
|
INIT_LIST_HEAD(&ent->list);
|
|
list_add_tail(&ent->list, &kprobe_blacklist);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Module notifier call back, checking kprobes on the module */
|
|
static int kprobes_module_callback(struct notifier_block *nb,
|
|
unsigned long val, void *data)
|
|
{
|
|
struct module *mod = data;
|
|
struct hlist_head *head;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
int checkcore = (val == MODULE_STATE_GOING);
|
|
|
|
if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
|
|
return NOTIFY_DONE;
|
|
|
|
/*
|
|
* When MODULE_STATE_GOING was notified, both of module .text and
|
|
* .init.text sections would be freed. When MODULE_STATE_LIVE was
|
|
* notified, only .init.text section would be freed. We need to
|
|
* disable kprobes which have been inserted in the sections.
|
|
*/
|
|
mutex_lock(&kprobe_mutex);
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, head, hlist)
|
|
if (within_module_init((unsigned long)p->addr, mod) ||
|
|
(checkcore &&
|
|
within_module_core((unsigned long)p->addr, mod))) {
|
|
/*
|
|
* The vaddr this probe is installed will soon
|
|
* be vfreed buy not synced to disk. Hence,
|
|
* disarming the breakpoint isn't needed.
|
|
*/
|
|
kill_kprobe(p);
|
|
}
|
|
}
|
|
mutex_unlock(&kprobe_mutex);
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block kprobe_module_nb = {
|
|
.notifier_call = kprobes_module_callback,
|
|
.priority = 0
|
|
};
|
|
|
|
/* Markers of _kprobe_blacklist section */
|
|
extern unsigned long __start_kprobe_blacklist[];
|
|
extern unsigned long __stop_kprobe_blacklist[];
|
|
|
|
static int __init init_kprobes(void)
|
|
{
|
|
int i, err = 0;
|
|
|
|
/* FIXME allocate the probe table, currently defined statically */
|
|
/* initialize all list heads */
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
INIT_HLIST_HEAD(&kprobe_table[i]);
|
|
INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
|
|
raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
|
|
}
|
|
|
|
err = populate_kprobe_blacklist(__start_kprobe_blacklist,
|
|
__stop_kprobe_blacklist);
|
|
if (err) {
|
|
pr_err("kprobes: failed to populate blacklist: %d\n", err);
|
|
pr_err("Please take care of using kprobes.\n");
|
|
}
|
|
|
|
if (kretprobe_blacklist_size) {
|
|
/* lookup the function address from its name */
|
|
for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
|
|
kprobe_lookup_name(kretprobe_blacklist[i].name,
|
|
kretprobe_blacklist[i].addr);
|
|
if (!kretprobe_blacklist[i].addr)
|
|
printk("kretprobe: lookup failed: %s\n",
|
|
kretprobe_blacklist[i].name);
|
|
}
|
|
}
|
|
|
|
#if defined(CONFIG_OPTPROBES)
|
|
#if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
|
|
/* Init kprobe_optinsn_slots */
|
|
kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
|
|
#endif
|
|
/* By default, kprobes can be optimized */
|
|
kprobes_allow_optimization = true;
|
|
#endif
|
|
|
|
/* By default, kprobes are armed */
|
|
kprobes_all_disarmed = false;
|
|
|
|
err = arch_init_kprobes();
|
|
if (!err)
|
|
err = register_die_notifier(&kprobe_exceptions_nb);
|
|
if (!err)
|
|
err = register_module_notifier(&kprobe_module_nb);
|
|
|
|
kprobes_initialized = (err == 0);
|
|
|
|
if (!err)
|
|
init_test_probes();
|
|
return err;
|
|
}
|
|
|
|
#ifdef CONFIG_DEBUG_FS
|
|
static void report_probe(struct seq_file *pi, struct kprobe *p,
|
|
const char *sym, int offset, char *modname, struct kprobe *pp)
|
|
{
|
|
char *kprobe_type;
|
|
|
|
if (p->pre_handler == pre_handler_kretprobe)
|
|
kprobe_type = "r";
|
|
else if (p->pre_handler == setjmp_pre_handler)
|
|
kprobe_type = "j";
|
|
else
|
|
kprobe_type = "k";
|
|
|
|
if (sym)
|
|
seq_printf(pi, "%p %s %s+0x%x %s ",
|
|
p->addr, kprobe_type, sym, offset,
|
|
(modname ? modname : " "));
|
|
else
|
|
seq_printf(pi, "%p %s %p ",
|
|
p->addr, kprobe_type, p->addr);
|
|
|
|
if (!pp)
|
|
pp = p;
|
|
seq_printf(pi, "%s%s%s%s\n",
|
|
(kprobe_gone(p) ? "[GONE]" : ""),
|
|
((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
|
|
(kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
|
|
(kprobe_ftrace(pp) ? "[FTRACE]" : ""));
|
|
}
|
|
|
|
static void *kprobe_seq_start(struct seq_file *f, loff_t *pos)
|
|
{
|
|
return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
|
|
}
|
|
|
|
static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
|
|
{
|
|
(*pos)++;
|
|
if (*pos >= KPROBE_TABLE_SIZE)
|
|
return NULL;
|
|
return pos;
|
|
}
|
|
|
|
static void kprobe_seq_stop(struct seq_file *f, void *v)
|
|
{
|
|
/* Nothing to do */
|
|
}
|
|
|
|
static int show_kprobe_addr(struct seq_file *pi, void *v)
|
|
{
|
|
struct hlist_head *head;
|
|
struct kprobe *p, *kp;
|
|
const char *sym = NULL;
|
|
unsigned int i = *(loff_t *) v;
|
|
unsigned long offset = 0;
|
|
char *modname, namebuf[KSYM_NAME_LEN];
|
|
|
|
head = &kprobe_table[i];
|
|
preempt_disable();
|
|
hlist_for_each_entry_rcu(p, head, hlist) {
|
|
sym = kallsyms_lookup((unsigned long)p->addr, NULL,
|
|
&offset, &modname, namebuf);
|
|
if (kprobe_aggrprobe(p)) {
|
|
list_for_each_entry_rcu(kp, &p->list, list)
|
|
report_probe(pi, kp, sym, offset, modname, p);
|
|
} else
|
|
report_probe(pi, p, sym, offset, modname, NULL);
|
|
}
|
|
preempt_enable();
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations kprobes_seq_ops = {
|
|
.start = kprobe_seq_start,
|
|
.next = kprobe_seq_next,
|
|
.stop = kprobe_seq_stop,
|
|
.show = show_kprobe_addr
|
|
};
|
|
|
|
static int kprobes_open(struct inode *inode, struct file *filp)
|
|
{
|
|
return seq_open(filp, &kprobes_seq_ops);
|
|
}
|
|
|
|
static const struct file_operations debugfs_kprobes_operations = {
|
|
.open = kprobes_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release,
|
|
};
|
|
|
|
/* kprobes/blacklist -- shows which functions can not be probed */
|
|
static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
return seq_list_start(&kprobe_blacklist, *pos);
|
|
}
|
|
|
|
static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
|
|
{
|
|
return seq_list_next(v, &kprobe_blacklist, pos);
|
|
}
|
|
|
|
static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
|
|
{
|
|
struct kprobe_blacklist_entry *ent =
|
|
list_entry(v, struct kprobe_blacklist_entry, list);
|
|
|
|
seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr,
|
|
(void *)ent->end_addr, (void *)ent->start_addr);
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations kprobe_blacklist_seq_ops = {
|
|
.start = kprobe_blacklist_seq_start,
|
|
.next = kprobe_blacklist_seq_next,
|
|
.stop = kprobe_seq_stop, /* Reuse void function */
|
|
.show = kprobe_blacklist_seq_show,
|
|
};
|
|
|
|
static int kprobe_blacklist_open(struct inode *inode, struct file *filp)
|
|
{
|
|
return seq_open(filp, &kprobe_blacklist_seq_ops);
|
|
}
|
|
|
|
static const struct file_operations debugfs_kprobe_blacklist_ops = {
|
|
.open = kprobe_blacklist_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release,
|
|
};
|
|
|
|
static void arm_all_kprobes(void)
|
|
{
|
|
struct hlist_head *head;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
/* If kprobes are armed, just return */
|
|
if (!kprobes_all_disarmed)
|
|
goto already_enabled;
|
|
|
|
/*
|
|
* optimize_kprobe() called by arm_kprobe() checks
|
|
* kprobes_all_disarmed, so set kprobes_all_disarmed before
|
|
* arm_kprobe.
|
|
*/
|
|
kprobes_all_disarmed = false;
|
|
/* Arming kprobes doesn't optimize kprobe itself */
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, head, hlist)
|
|
if (!kprobe_disabled(p))
|
|
arm_kprobe(p);
|
|
}
|
|
|
|
printk(KERN_INFO "Kprobes globally enabled\n");
|
|
|
|
already_enabled:
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
|
|
static void disarm_all_kprobes(void)
|
|
{
|
|
struct hlist_head *head;
|
|
struct kprobe *p;
|
|
unsigned int i;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
|
|
/* If kprobes are already disarmed, just return */
|
|
if (kprobes_all_disarmed) {
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
|
|
kprobes_all_disarmed = true;
|
|
printk(KERN_INFO "Kprobes globally disabled\n");
|
|
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, head, hlist) {
|
|
if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
|
|
disarm_kprobe(p, false);
|
|
}
|
|
}
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
/* Wait for disarming all kprobes by optimizer */
|
|
wait_for_kprobe_optimizer();
|
|
}
|
|
|
|
/*
|
|
* XXX: The debugfs bool file interface doesn't allow for callbacks
|
|
* when the bool state is switched. We can reuse that facility when
|
|
* available
|
|
*/
|
|
static ssize_t read_enabled_file_bool(struct file *file,
|
|
char __user *user_buf, size_t count, loff_t *ppos)
|
|
{
|
|
char buf[3];
|
|
|
|
if (!kprobes_all_disarmed)
|
|
buf[0] = '1';
|
|
else
|
|
buf[0] = '0';
|
|
buf[1] = '\n';
|
|
buf[2] = 0x00;
|
|
return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
|
|
}
|
|
|
|
static ssize_t write_enabled_file_bool(struct file *file,
|
|
const char __user *user_buf, size_t count, loff_t *ppos)
|
|
{
|
|
char buf[32];
|
|
size_t buf_size;
|
|
|
|
buf_size = min(count, (sizeof(buf)-1));
|
|
if (copy_from_user(buf, user_buf, buf_size))
|
|
return -EFAULT;
|
|
|
|
buf[buf_size] = '\0';
|
|
switch (buf[0]) {
|
|
case 'y':
|
|
case 'Y':
|
|
case '1':
|
|
arm_all_kprobes();
|
|
break;
|
|
case 'n':
|
|
case 'N':
|
|
case '0':
|
|
disarm_all_kprobes();
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
return count;
|
|
}
|
|
|
|
static const struct file_operations fops_kp = {
|
|
.read = read_enabled_file_bool,
|
|
.write = write_enabled_file_bool,
|
|
.llseek = default_llseek,
|
|
};
|
|
|
|
static int __init debugfs_kprobe_init(void)
|
|
{
|
|
struct dentry *dir, *file;
|
|
unsigned int value = 1;
|
|
|
|
dir = debugfs_create_dir("kprobes", NULL);
|
|
if (!dir)
|
|
return -ENOMEM;
|
|
|
|
file = debugfs_create_file("list", 0444, dir, NULL,
|
|
&debugfs_kprobes_operations);
|
|
if (!file)
|
|
goto error;
|
|
|
|
file = debugfs_create_file("enabled", 0600, dir,
|
|
&value, &fops_kp);
|
|
if (!file)
|
|
goto error;
|
|
|
|
file = debugfs_create_file("blacklist", 0444, dir, NULL,
|
|
&debugfs_kprobe_blacklist_ops);
|
|
if (!file)
|
|
goto error;
|
|
|
|
return 0;
|
|
|
|
error:
|
|
debugfs_remove(dir);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
late_initcall(debugfs_kprobe_init);
|
|
#endif /* CONFIG_DEBUG_FS */
|
|
|
|
module_init(init_kprobes);
|
|
|
|
/* defined in arch/.../kernel/kprobes.c */
|
|
EXPORT_SYMBOL_GPL(jprobe_return);
|