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![Rusty Lynch](/assets/img/avatar_default.png)
The following renames arch_init, a kprobes function for performing any architecture specific initialization, to arch_init_kprobes in order to cleanup the namespace. Also, this patch adds arch_init_kprobes to sparc64 to fix the sparc64 kprobes build from the last return probe patch. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
593 lines
15 KiB
C
593 lines
15 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/spinlock.h>
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#include <linux/hash.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/moduleloader.h>
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#include <asm/cacheflush.h>
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#include <asm/errno.h>
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#include <asm/kdebug.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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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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unsigned int kprobe_cpu = NR_CPUS;
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static DEFINE_SPINLOCK(kprobe_lock);
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static struct kprobe *curr_kprobe;
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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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};
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static struct hlist_head kprobe_insn_pages;
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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(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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hlist_for_each(pos, &kprobe_insn_pages) {
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kip = hlist_entry(pos, struct kprobe_insn_page, 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]) {
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kip->slot_used[i] = 1;
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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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/* 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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/*
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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, 0, INSNS_PER_PAGE);
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kip->slot_used[0] = 1;
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kip->nused = 1;
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return kip->insns;
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}
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void free_insn_slot(kprobe_opcode_t *slot)
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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(pos, &kprobe_insn_pages) {
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kip = hlist_entry(pos, struct kprobe_insn_page, 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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kip->slot_used[i] = 0;
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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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}
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return;
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}
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}
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}
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/* Locks kprobe: irqs must be disabled */
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void lock_kprobes(void)
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{
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spin_lock(&kprobe_lock);
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kprobe_cpu = smp_processor_id();
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}
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void unlock_kprobes(void)
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{
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kprobe_cpu = NR_CPUS;
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spin_unlock(&kprobe_lock);
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}
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/* You have to be holding the kprobe_lock */
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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 hlist_node *node;
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head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
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hlist_for_each(node, head) {
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struct kprobe *p = hlist_entry(node, struct kprobe, 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 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(kp, &p->list, list) {
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if (kp->pre_handler) {
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curr_kprobe = 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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curr_kprobe = NULL;
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}
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return 0;
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}
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static void 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(kp, &p->list, list) {
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if (kp->post_handler) {
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curr_kprobe = kp;
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kp->post_handler(kp, regs, flags);
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curr_kprobe = NULL;
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}
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}
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return;
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}
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static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
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int trapnr)
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{
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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 (curr_kprobe && curr_kprobe->fault_handler) {
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if (curr_kprobe->fault_handler(curr_kprobe, 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 aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
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{
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struct kprobe *kp = curr_kprobe;
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if (curr_kprobe && kp->break_handler) {
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if (kp->break_handler(kp, regs)) {
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curr_kprobe = NULL;
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return 1;
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}
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}
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curr_kprobe = NULL;
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return 0;
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}
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struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp)
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{
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struct hlist_node *node;
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struct kretprobe_instance *ri;
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hlist_for_each_entry(ri, node, &rp->free_instances, uflist)
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return ri;
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return NULL;
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}
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static struct kretprobe_instance *get_used_rp_inst(struct kretprobe *rp)
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{
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struct hlist_node *node;
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struct kretprobe_instance *ri;
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hlist_for_each_entry(ri, node, &rp->used_instances, uflist)
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return ri;
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return NULL;
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}
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void add_rp_inst(struct kretprobe_instance *ri)
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{
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/*
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* Remove rp inst off the free list -
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* Add it back when probed function returns
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*/
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hlist_del(&ri->uflist);
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/* Add rp inst onto table */
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INIT_HLIST_NODE(&ri->hlist);
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hlist_add_head(&ri->hlist,
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&kretprobe_inst_table[hash_ptr(ri->task, KPROBE_HASH_BITS)]);
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/* Also add this rp inst to the used list. */
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INIT_HLIST_NODE(&ri->uflist);
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hlist_add_head(&ri->uflist, &ri->rp->used_instances);
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}
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void recycle_rp_inst(struct kretprobe_instance *ri)
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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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kfree(ri);
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}
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struct hlist_head * 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 exit_thread or flush_thread when task tk's
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* stack is being recycled so that we can recycle any function-return probe
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* instances associated with this task. These left over instances represent
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* probed functions that have been called but will never return.
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*/
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void 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;
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struct hlist_node *node, *tmp;
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unsigned long flags = 0;
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spin_lock_irqsave(&kprobe_lock, flags);
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head = kretprobe_inst_table_head(current);
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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);
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}
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spin_unlock_irqrestore(&kprobe_lock, flags);
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}
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/*
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* This kprobe pre_handler is registered with every kretprobe. When probe
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* hits it will set up the return probe.
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*/
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static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
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{
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struct kretprobe *rp = container_of(p, struct kretprobe, kp);
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/*TODO: consider to only swap the RA after the last pre_handler fired */
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arch_prepare_kretprobe(rp, regs);
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return 0;
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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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while ((ri = get_free_rp_inst(rp)) != NULL) {
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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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* 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 add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
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{
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struct kprobe *kp;
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if (p->break_handler) {
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list_for_each_entry(kp, &old_p->list, list) {
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if (kp->break_handler)
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return -EEXIST;
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}
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list_add_tail(&p->list, &old_p->list);
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} else
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list_add(&p->list, &old_p->list);
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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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ap->addr = p->addr;
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ap->pre_handler = aggr_pre_handler;
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ap->post_handler = aggr_post_handler;
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ap->fault_handler = aggr_fault_handler;
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ap->break_handler = aggr_break_handler;
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INIT_LIST_HEAD(&ap->list);
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list_add(&p->list, &ap->list);
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INIT_HLIST_NODE(&ap->hlist);
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hlist_del(&p->hlist);
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hlist_add_head(&ap->hlist,
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&kprobe_table[hash_ptr(ap->addr, KPROBE_HASH_BITS)]);
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}
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/*
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* This is the second or subsequent kprobe at the address - handle
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* the intricacies
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* TODO: Move kcalloc outside the spinlock
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*/
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static int register_aggr_kprobe(struct kprobe *old_p, struct kprobe *p)
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{
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int ret = 0;
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struct kprobe *ap;
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if (old_p->pre_handler == aggr_pre_handler) {
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copy_kprobe(old_p, p);
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ret = add_new_kprobe(old_p, p);
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} else {
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ap = kcalloc(1, sizeof(struct kprobe), GFP_ATOMIC);
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if (!ap)
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return -ENOMEM;
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add_aggr_kprobe(ap, old_p);
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copy_kprobe(ap, p);
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ret = add_new_kprobe(ap, p);
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}
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return ret;
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}
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/* kprobe removal house-keeping routines */
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static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags)
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{
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arch_disarm_kprobe(p);
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hlist_del(&p->hlist);
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spin_unlock_irqrestore(&kprobe_lock, flags);
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arch_remove_kprobe(p);
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}
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static inline void cleanup_aggr_kprobe(struct kprobe *old_p,
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struct kprobe *p, unsigned long flags)
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{
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list_del(&p->list);
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if (list_empty(&old_p->list)) {
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cleanup_kprobe(old_p, flags);
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kfree(old_p);
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} else
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spin_unlock_irqrestore(&kprobe_lock, flags);
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}
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int register_kprobe(struct kprobe *p)
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{
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int ret = 0;
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unsigned long flags = 0;
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struct kprobe *old_p;
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if ((ret = arch_prepare_kprobe(p)) != 0) {
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goto rm_kprobe;
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}
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spin_lock_irqsave(&kprobe_lock, flags);
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old_p = get_kprobe(p->addr);
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p->nmissed = 0;
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if (old_p) {
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ret = register_aggr_kprobe(old_p, p);
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goto out;
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}
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arch_copy_kprobe(p);
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INIT_HLIST_NODE(&p->hlist);
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hlist_add_head(&p->hlist,
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&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
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arch_arm_kprobe(p);
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out:
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spin_unlock_irqrestore(&kprobe_lock, flags);
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rm_kprobe:
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if (ret == -EEXIST)
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arch_remove_kprobe(p);
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return ret;
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}
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void unregister_kprobe(struct kprobe *p)
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{
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unsigned long flags;
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struct kprobe *old_p;
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spin_lock_irqsave(&kprobe_lock, flags);
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old_p = get_kprobe(p->addr);
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if (old_p) {
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if (old_p->pre_handler == aggr_pre_handler)
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cleanup_aggr_kprobe(old_p, p, flags);
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else
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cleanup_kprobe(p, flags);
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} else
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spin_unlock_irqrestore(&kprobe_lock, flags);
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}
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static struct notifier_block kprobe_exceptions_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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int register_jprobe(struct jprobe *jp)
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{
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/* Todo: Verify probepoint is a function entry point */
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jp->kp.pre_handler = setjmp_pre_handler;
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jp->kp.break_handler = longjmp_break_handler;
|
|
|
|
return register_kprobe(&jp->kp);
|
|
}
|
|
|
|
void unregister_jprobe(struct jprobe *jp)
|
|
{
|
|
unregister_kprobe(&jp->kp);
|
|
}
|
|
|
|
#ifdef ARCH_SUPPORTS_KRETPROBES
|
|
|
|
int register_kretprobe(struct kretprobe *rp)
|
|
{
|
|
int ret = 0;
|
|
struct kretprobe_instance *inst;
|
|
int i;
|
|
|
|
rp->kp.pre_handler = pre_handler_kretprobe;
|
|
|
|
/* 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)) != 0)
|
|
free_rp_inst(rp);
|
|
return ret;
|
|
}
|
|
|
|
#else /* ARCH_SUPPORTS_KRETPROBES */
|
|
|
|
int register_kretprobe(struct kretprobe *rp)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
|
|
#endif /* ARCH_SUPPORTS_KRETPROBES */
|
|
|
|
void unregister_kretprobe(struct kretprobe *rp)
|
|
{
|
|
unsigned long flags;
|
|
struct kretprobe_instance *ri;
|
|
|
|
unregister_kprobe(&rp->kp);
|
|
/* No race here */
|
|
spin_lock_irqsave(&kprobe_lock, flags);
|
|
free_rp_inst(rp);
|
|
while ((ri = get_used_rp_inst(rp)) != NULL) {
|
|
ri->rp = NULL;
|
|
hlist_del(&ri->uflist);
|
|
}
|
|
spin_unlock_irqrestore(&kprobe_lock, flags);
|
|
}
|
|
|
|
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]);
|
|
}
|
|
|
|
err = arch_init_kprobes();
|
|
if (!err)
|
|
err = register_die_notifier(&kprobe_exceptions_nb);
|
|
|
|
return err;
|
|
}
|
|
|
|
__initcall(init_kprobes);
|
|
|
|
EXPORT_SYMBOL_GPL(register_kprobe);
|
|
EXPORT_SYMBOL_GPL(unregister_kprobe);
|
|
EXPORT_SYMBOL_GPL(register_jprobe);
|
|
EXPORT_SYMBOL_GPL(unregister_jprobe);
|
|
EXPORT_SYMBOL_GPL(jprobe_return);
|
|
EXPORT_SYMBOL_GPL(register_kretprobe);
|
|
EXPORT_SYMBOL_GPL(unregister_kretprobe);
|
|
|