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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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cd5bfea278
gcc-4.2 is a lot more picky about its symbol handling. EXPORT_SYMBOL no longer works on symbols that are undefined or defined with static scope. For example, with CONFIG_PROFILE off, I see: kernel/profile.c:206: error: __ksymtab_profile_event_unregister causes a section type conflict kernel/profile.c:205: error: __ksymtab_profile_event_register causes a section type conflict This patch moves the EXPORTs inside the #ifdef CONFIG_PROFILE, so we only try to export symbols that are defined. Also, in kernel/kprobes.c there's an EXPORT_SYMBOL_GPL() for jprobes_return, which if CONFIG_JPROBES is undefined is a static inline and gives the same error. And in drivers/acpi/resources/rsxface.c, there's an ACPI_EXPORT_SYMBOPL() for a static symbol. If it's static, it's not accessible from outside the compilation unit, so should bot be exported. These three changes allow building a zx1_defconfig kernel with gcc 4.2 on IA64. [akpm@linux-foundation.org: export jpobe_return properly] Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au> Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Len Brown <lenb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1073 lines
26 KiB
C
1073 lines
26 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/module.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/kdebug.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 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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static atomic_t kprobe_count;
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/* NOTE: change this value only with kprobe_mutex held */
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static bool kprobe_enabled;
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DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
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DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */
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static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
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static struct notifier_block kprobe_page_fault_nb = {
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.notifier_call = kprobe_exceptions_notify,
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.priority = 0x7fffffff /* we need to notified first */
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};
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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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#define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
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struct kprobe_insn_page {
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struct hlist_node hlist;
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kprobe_opcode_t *insns; /* Page of instruction slots */
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char slot_used[INSNS_PER_PAGE];
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int nused;
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int ngarbage;
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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 struct hlist_head kprobe_insn_pages;
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static int kprobe_garbage_slots;
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static int collect_garbage_slots(void);
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static int __kprobes check_safety(void)
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{
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int ret = 0;
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#if defined(CONFIG_PREEMPT) && defined(CONFIG_PM)
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ret = freeze_processes();
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if (ret == 0) {
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struct task_struct *p, *q;
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do_each_thread(p, q) {
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if (p != current && p->state == TASK_RUNNING &&
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p->pid != 0) {
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printk("Check failed: %s is running\n",p->comm);
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ret = -1;
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goto loop_end;
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}
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} while_each_thread(p, q);
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}
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loop_end:
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thaw_processes();
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#else
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synchronize_sched();
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#endif
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return ret;
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}
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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 __kprobes *get_insn_slot(void)
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{
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struct kprobe_insn_page *kip;
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struct hlist_node *pos;
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retry:
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hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
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if (kip->nused < INSNS_PER_PAGE) {
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int i;
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for (i = 0; i < INSNS_PER_PAGE; 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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return kip->insns + (i * MAX_INSN_SIZE);
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}
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}
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/* Surprise! No unused slots. Fix kip->nused. */
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kip->nused = INSNS_PER_PAGE;
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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 (kprobe_garbage_slots && collect_garbage_slots() == 0) {
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goto retry;
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}
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/* All out of space. Need to allocate a new page. Use slot 0. */
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kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
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if (!kip)
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return NULL;
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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 = module_alloc(PAGE_SIZE);
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if (!kip->insns) {
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kfree(kip);
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return NULL;
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}
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INIT_HLIST_NODE(&kip->hlist);
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hlist_add_head(&kip->hlist, &kprobe_insn_pages);
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memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE);
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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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return kip->insns;
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}
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/* Return 1 if all garbages are collected, otherwise 0. */
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static int __kprobes 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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hlist_del(&kip->hlist);
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if (hlist_empty(&kprobe_insn_pages)) {
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INIT_HLIST_NODE(&kip->hlist);
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hlist_add_head(&kip->hlist,
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&kprobe_insn_pages);
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} else {
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module_free(NULL, 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 __kprobes collect_garbage_slots(void)
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{
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struct kprobe_insn_page *kip;
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struct hlist_node *pos, *next;
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/* Ensure no-one is preepmted on the garbages */
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if (check_safety() != 0)
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return -EAGAIN;
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hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
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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 < INSNS_PER_PAGE; 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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kprobe_garbage_slots = 0;
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return 0;
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}
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void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
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{
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struct kprobe_insn_page *kip;
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struct hlist_node *pos;
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hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
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if (kip->insns <= slot &&
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slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
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int i = (slot - kip->insns) / MAX_INSN_SIZE;
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if (dirty) {
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kip->slot_used[i] = SLOT_DIRTY;
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kip->ngarbage++;
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} else {
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collect_one_slot(kip, i);
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}
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break;
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}
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}
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if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
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collect_garbage_slots();
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}
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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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__get_cpu_var(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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__get_cpu_var(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 __kprobes *get_kprobe(void *addr)
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{
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struct hlist_head *head;
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struct hlist_node *node;
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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, node, 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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/*
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* Aggregate handlers for multiple kprobes support - these handlers
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* take care of invoking the individual kprobe handlers on p->list
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*/
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static int __kprobes aggr_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) {
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set_kprobe_instance(kp);
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if (kp->pre_handler(kp, regs))
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return 1;
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}
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reset_kprobe_instance();
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}
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return 0;
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}
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static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
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unsigned long flags)
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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->post_handler) {
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set_kprobe_instance(kp);
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kp->post_handler(kp, regs, flags);
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reset_kprobe_instance();
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}
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}
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}
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static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
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int trapnr)
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{
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struct kprobe *cur = __get_cpu_var(kprobe_instance);
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/*
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* if we faulted "during" the execution of a user specified
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* probe handler, invoke just that probe's fault handler
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*/
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if (cur && cur->fault_handler) {
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if (cur->fault_handler(cur, regs, trapnr))
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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 __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
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{
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struct kprobe *cur = __get_cpu_var(kprobe_instance);
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int ret = 0;
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if (cur && cur->break_handler) {
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if (cur->break_handler(cur, regs))
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ret = 1;
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}
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reset_kprobe_instance();
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return ret;
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}
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/* Walks the list and increments nmissed count for multiprobe case */
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void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
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{
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struct kprobe *kp;
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if (p->pre_handler != aggr_pre_handler) {
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p->nmissed++;
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} else {
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list_for_each_entry_rcu(kp, &p->list, list)
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kp->nmissed++;
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}
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return;
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}
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/* Called with kretprobe_lock held */
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void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
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struct hlist_head *head)
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{
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/* remove rp inst off the rprobe_inst_table */
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hlist_del(&ri->hlist);
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if (ri->rp) {
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/* remove rp inst off the used list */
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hlist_del(&ri->uflist);
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/* put rp inst back onto the free list */
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INIT_HLIST_NODE(&ri->uflist);
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hlist_add_head(&ri->uflist, &ri->rp->free_instances);
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} else
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/* Unregistering */
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hlist_add_head(&ri->hlist, head);
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}
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struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
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{
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return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)];
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}
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/*
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* This function is called from finish_task_switch when task tk becomes dead,
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* so that we can recycle any function-return probe instances associated
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* with this task. These left over instances represent probed functions
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* that have been called but will never return.
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*/
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void __kprobes kprobe_flush_task(struct task_struct *tk)
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{
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struct kretprobe_instance *ri;
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struct hlist_head *head, empty_rp;
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struct hlist_node *node, *tmp;
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unsigned long flags = 0;
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INIT_HLIST_HEAD(&empty_rp);
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spin_lock_irqsave(&kretprobe_lock, flags);
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head = kretprobe_inst_table_head(tk);
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hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
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if (ri->task == tk)
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recycle_rp_inst(ri, &empty_rp);
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}
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spin_unlock_irqrestore(&kretprobe_lock, flags);
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hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
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hlist_del(&ri->hlist);
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kfree(ri);
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}
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}
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static inline void free_rp_inst(struct kretprobe *rp)
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{
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struct kretprobe_instance *ri;
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struct hlist_node *pos, *next;
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hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, uflist) {
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hlist_del(&ri->uflist);
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kfree(ri);
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}
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}
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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 *old_p, struct kprobe *p)
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{
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memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
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memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
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}
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/*
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* Add the new probe to old_p->list. Fail if this is the
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* second jprobe at the address - two jprobes can't coexist
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*/
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static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
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{
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if (p->break_handler) {
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if (old_p->break_handler)
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return -EEXIST;
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list_add_tail_rcu(&p->list, &old_p->list);
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old_p->break_handler = aggr_break_handler;
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} else
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list_add_rcu(&p->list, &old_p->list);
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if (p->post_handler && !old_p->post_handler)
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old_p->post_handler = aggr_post_handler;
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return 0;
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}
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|
|
/*
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* Fill in the required fields of the "manager kprobe". Replace the
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* earlier kprobe in the hlist with the manager kprobe
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*/
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static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
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{
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copy_kprobe(p, ap);
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flush_insn_slot(ap);
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ap->addr = p->addr;
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ap->pre_handler = aggr_pre_handler;
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ap->fault_handler = aggr_fault_handler;
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if (p->post_handler)
|
|
ap->post_handler = aggr_post_handler;
|
|
if (p->break_handler)
|
|
ap->break_handler = aggr_break_handler;
|
|
|
|
INIT_LIST_HEAD(&ap->list);
|
|
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 *old_p,
|
|
struct kprobe *p)
|
|
{
|
|
int ret = 0;
|
|
struct kprobe *ap;
|
|
|
|
if (old_p->pre_handler == aggr_pre_handler) {
|
|
copy_kprobe(old_p, p);
|
|
ret = add_new_kprobe(old_p, p);
|
|
} else {
|
|
ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
|
|
if (!ap)
|
|
return -ENOMEM;
|
|
add_aggr_kprobe(ap, old_p);
|
|
copy_kprobe(ap, p);
|
|
ret = add_new_kprobe(ap, p);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int __kprobes in_kprobes_functions(unsigned long addr)
|
|
{
|
|
if (addr >= (unsigned long)__kprobes_text_start &&
|
|
addr < (unsigned long)__kprobes_text_end)
|
|
return -EINVAL;
|
|
return 0;
|
|
}
|
|
|
|
static int __kprobes __register_kprobe(struct kprobe *p,
|
|
unsigned long called_from)
|
|
{
|
|
int ret = 0;
|
|
struct kprobe *old_p;
|
|
struct module *probed_mod;
|
|
|
|
/*
|
|
* If we have a symbol_name argument look it up,
|
|
* and add it to the address. That way the addr
|
|
* field can either be global or relative to a symbol.
|
|
*/
|
|
if (p->symbol_name) {
|
|
if (p->addr)
|
|
return -EINVAL;
|
|
kprobe_lookup_name(p->symbol_name, p->addr);
|
|
}
|
|
|
|
if (!p->addr)
|
|
return -EINVAL;
|
|
p->addr = (kprobe_opcode_t *)(((char *)p->addr)+ p->offset);
|
|
|
|
if (!kernel_text_address((unsigned long) p->addr) ||
|
|
in_kprobes_functions((unsigned long) p->addr))
|
|
return -EINVAL;
|
|
|
|
p->mod_refcounted = 0;
|
|
|
|
/*
|
|
* Check if are we probing a module.
|
|
*/
|
|
probed_mod = module_text_address((unsigned long) p->addr);
|
|
if (probed_mod) {
|
|
struct module *calling_mod = module_text_address(called_from);
|
|
/*
|
|
* We must allow modules to probe themself and in this case
|
|
* avoid incrementing the module refcount, so as to allow
|
|
* unloading of self probing modules.
|
|
*/
|
|
if (calling_mod && calling_mod != probed_mod) {
|
|
if (unlikely(!try_module_get(probed_mod)))
|
|
return -EINVAL;
|
|
p->mod_refcounted = 1;
|
|
} else
|
|
probed_mod = NULL;
|
|
}
|
|
|
|
p->nmissed = 0;
|
|
mutex_lock(&kprobe_mutex);
|
|
old_p = get_kprobe(p->addr);
|
|
if (old_p) {
|
|
ret = register_aggr_kprobe(old_p, p);
|
|
if (!ret)
|
|
atomic_inc(&kprobe_count);
|
|
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 (kprobe_enabled) {
|
|
if (atomic_add_return(1, &kprobe_count) == \
|
|
(ARCH_INACTIVE_KPROBE_COUNT + 1))
|
|
register_page_fault_notifier(&kprobe_page_fault_nb);
|
|
|
|
arch_arm_kprobe(p);
|
|
}
|
|
out:
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
if (ret && probed_mod)
|
|
module_put(probed_mod);
|
|
return ret;
|
|
}
|
|
|
|
int __kprobes register_kprobe(struct kprobe *p)
|
|
{
|
|
return __register_kprobe(p, (unsigned long)__builtin_return_address(0));
|
|
}
|
|
|
|
void __kprobes unregister_kprobe(struct kprobe *p)
|
|
{
|
|
struct module *mod;
|
|
struct kprobe *old_p, *list_p;
|
|
int cleanup_p;
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
old_p = get_kprobe(p->addr);
|
|
if (unlikely(!old_p)) {
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
if (p != old_p) {
|
|
list_for_each_entry_rcu(list_p, &old_p->list, list)
|
|
if (list_p == p)
|
|
/* kprobe p is a valid probe */
|
|
goto valid_p;
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
valid_p:
|
|
if (old_p == p ||
|
|
(old_p->pre_handler == aggr_pre_handler &&
|
|
p->list.next == &old_p->list && p->list.prev == &old_p->list)) {
|
|
/*
|
|
* Only probe on the hash list. Disarm only if kprobes are
|
|
* enabled - otherwise, the breakpoint would already have
|
|
* been removed. We save on flushing icache.
|
|
*/
|
|
if (kprobe_enabled)
|
|
arch_disarm_kprobe(p);
|
|
hlist_del_rcu(&old_p->hlist);
|
|
cleanup_p = 1;
|
|
} else {
|
|
list_del_rcu(&p->list);
|
|
cleanup_p = 0;
|
|
}
|
|
|
|
mutex_unlock(&kprobe_mutex);
|
|
|
|
synchronize_sched();
|
|
if (p->mod_refcounted) {
|
|
mod = module_text_address((unsigned long)p->addr);
|
|
if (mod)
|
|
module_put(mod);
|
|
}
|
|
|
|
if (cleanup_p) {
|
|
if (p != old_p) {
|
|
list_del_rcu(&p->list);
|
|
kfree(old_p);
|
|
}
|
|
arch_remove_kprobe(p);
|
|
} else {
|
|
mutex_lock(&kprobe_mutex);
|
|
if (p->break_handler)
|
|
old_p->break_handler = NULL;
|
|
if (p->post_handler){
|
|
list_for_each_entry_rcu(list_p, &old_p->list, list){
|
|
if (list_p->post_handler){
|
|
cleanup_p = 2;
|
|
break;
|
|
}
|
|
}
|
|
if (cleanup_p == 0)
|
|
old_p->post_handler = NULL;
|
|
}
|
|
mutex_unlock(&kprobe_mutex);
|
|
}
|
|
|
|
/* Call unregister_page_fault_notifier()
|
|
* if no probes are active
|
|
*/
|
|
mutex_lock(&kprobe_mutex);
|
|
if (atomic_add_return(-1, &kprobe_count) == \
|
|
ARCH_INACTIVE_KPROBE_COUNT)
|
|
unregister_page_fault_notifier(&kprobe_page_fault_nb);
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
|
|
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_jprobe(struct jprobe *jp)
|
|
{
|
|
unsigned long addr = arch_deref_entry_point(jp->entry);
|
|
|
|
if (!kernel_text_address(addr))
|
|
return -EINVAL;
|
|
|
|
/* Todo: Verify probepoint is a function entry point */
|
|
jp->kp.pre_handler = setjmp_pre_handler;
|
|
jp->kp.break_handler = longjmp_break_handler;
|
|
|
|
return __register_kprobe(&jp->kp,
|
|
(unsigned long)__builtin_return_address(0));
|
|
}
|
|
|
|
void __kprobes unregister_jprobe(struct jprobe *jp)
|
|
{
|
|
unregister_kprobe(&jp->kp);
|
|
}
|
|
|
|
#ifdef ARCH_SUPPORTS_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 flags = 0;
|
|
|
|
/*TODO: consider to only swap the RA after the last pre_handler fired */
|
|
spin_lock_irqsave(&kretprobe_lock, flags);
|
|
if (!hlist_empty(&rp->free_instances)) {
|
|
struct kretprobe_instance *ri;
|
|
|
|
ri = hlist_entry(rp->free_instances.first,
|
|
struct kretprobe_instance, uflist);
|
|
ri->rp = rp;
|
|
ri->task = current;
|
|
arch_prepare_kretprobe(ri, regs);
|
|
|
|
/* XXX(hch): why is there no hlist_move_head? */
|
|
hlist_del(&ri->uflist);
|
|
hlist_add_head(&ri->uflist, &ri->rp->used_instances);
|
|
hlist_add_head(&ri->hlist, kretprobe_inst_table_head(ri->task));
|
|
} else
|
|
rp->nmissed++;
|
|
spin_unlock_irqrestore(&kretprobe_lock, flags);
|
|
return 0;
|
|
}
|
|
|
|
int __kprobes register_kretprobe(struct kretprobe *rp)
|
|
{
|
|
int ret = 0;
|
|
struct kretprobe_instance *inst;
|
|
int i;
|
|
|
|
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(10, 2 * NR_CPUS);
|
|
#else
|
|
rp->maxactive = NR_CPUS;
|
|
#endif
|
|
}
|
|
INIT_HLIST_HEAD(&rp->used_instances);
|
|
INIT_HLIST_HEAD(&rp->free_instances);
|
|
for (i = 0; i < rp->maxactive; i++) {
|
|
inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL);
|
|
if (inst == NULL) {
|
|
free_rp_inst(rp);
|
|
return -ENOMEM;
|
|
}
|
|
INIT_HLIST_NODE(&inst->uflist);
|
|
hlist_add_head(&inst->uflist, &rp->free_instances);
|
|
}
|
|
|
|
rp->nmissed = 0;
|
|
/* Establish function entry probe point */
|
|
if ((ret = __register_kprobe(&rp->kp,
|
|
(unsigned long)__builtin_return_address(0))) != 0)
|
|
free_rp_inst(rp);
|
|
return ret;
|
|
}
|
|
|
|
#else /* ARCH_SUPPORTS_KRETPROBES */
|
|
|
|
int __kprobes register_kretprobe(struct kretprobe *rp)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
|
|
static int __kprobes pre_handler_kretprobe(struct kprobe *p,
|
|
struct pt_regs *regs)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif /* ARCH_SUPPORTS_KRETPROBES */
|
|
|
|
void __kprobes unregister_kretprobe(struct kretprobe *rp)
|
|
{
|
|
unsigned long flags;
|
|
struct kretprobe_instance *ri;
|
|
struct hlist_node *pos, *next;
|
|
|
|
unregister_kprobe(&rp->kp);
|
|
|
|
/* No race here */
|
|
spin_lock_irqsave(&kretprobe_lock, flags);
|
|
hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) {
|
|
ri->rp = NULL;
|
|
hlist_del(&ri->uflist);
|
|
}
|
|
spin_unlock_irqrestore(&kretprobe_lock, flags);
|
|
free_rp_inst(rp);
|
|
}
|
|
|
|
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]);
|
|
}
|
|
atomic_set(&kprobe_count, 0);
|
|
|
|
/* By default, kprobes are enabled */
|
|
kprobe_enabled = true;
|
|
|
|
err = arch_init_kprobes();
|
|
if (!err)
|
|
err = register_die_notifier(&kprobe_exceptions_nb);
|
|
|
|
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)
|
|
{
|
|
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\n", p->addr, kprobe_type,
|
|
sym, offset, (modname ? modname : " "));
|
|
else
|
|
seq_printf(pi, "%p %s %p\n", p->addr, kprobe_type, p->addr);
|
|
}
|
|
|
|
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 (p->pre_handler == aggr_pre_handler) {
|
|
list_for_each_entry_rcu(kp, &p->list, list)
|
|
report_probe(pi, kp, sym, offset, modname);
|
|
} else
|
|
report_probe(pi, p, sym, offset, modname);
|
|
}
|
|
preempt_enable();
|
|
return 0;
|
|
}
|
|
|
|
static 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 struct file_operations debugfs_kprobes_operations = {
|
|
.open = kprobes_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release,
|
|
};
|
|
|
|
static void __kprobes enable_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 enabled, just return */
|
|
if (kprobe_enabled)
|
|
goto already_enabled;
|
|
|
|
/*
|
|
* Re-register the page fault notifier only if there are any
|
|
* active probes at the time of enabling kprobes globally
|
|
*/
|
|
if (atomic_read(&kprobe_count) > ARCH_INACTIVE_KPROBE_COUNT)
|
|
register_page_fault_notifier(&kprobe_page_fault_nb);
|
|
|
|
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
|
|
head = &kprobe_table[i];
|
|
hlist_for_each_entry_rcu(p, node, head, hlist)
|
|
arch_arm_kprobe(p);
|
|
}
|
|
|
|
kprobe_enabled = true;
|
|
printk(KERN_INFO "Kprobes globally enabled\n");
|
|
|
|
already_enabled:
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
|
|
static void __kprobes disable_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 disabled, just return */
|
|
if (!kprobe_enabled)
|
|
goto already_disabled;
|
|
|
|
kprobe_enabled = false;
|
|
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, node, head, hlist) {
|
|
if (!arch_trampoline_kprobe(p))
|
|
arch_disarm_kprobe(p);
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&kprobe_mutex);
|
|
/* Allow all currently running kprobes to complete */
|
|
synchronize_sched();
|
|
|
|
mutex_lock(&kprobe_mutex);
|
|
/* Unconditionally unregister the page_fault notifier */
|
|
unregister_page_fault_notifier(&kprobe_page_fault_nb);
|
|
|
|
already_disabled:
|
|
mutex_unlock(&kprobe_mutex);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* 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 (kprobe_enabled)
|
|
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];
|
|
int 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':
|
|
enable_all_kprobes();
|
|
break;
|
|
case 'n':
|
|
case 'N':
|
|
case '0':
|
|
disable_all_kprobes();
|
|
break;
|
|
}
|
|
|
|
return count;
|
|
}
|
|
|
|
static struct file_operations fops_kp = {
|
|
.read = read_enabled_file_bool,
|
|
.write = write_enabled_file_bool,
|
|
};
|
|
|
|
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);
|
|
|
|
EXPORT_SYMBOL_GPL(register_kprobe);
|
|
EXPORT_SYMBOL_GPL(unregister_kprobe);
|
|
EXPORT_SYMBOL_GPL(register_jprobe);
|
|
EXPORT_SYMBOL_GPL(unregister_jprobe);
|
|
#ifdef CONFIG_KPROBES
|
|
EXPORT_SYMBOL_GPL(jprobe_return);
|
|
#endif
|
|
|
|
#ifdef CONFIG_KPROBES
|
|
EXPORT_SYMBOL_GPL(register_kretprobe);
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobe);
|
|
#endif
|