1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
158 lines
4.2 KiB
C
158 lines
4.2 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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*/
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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 <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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unsigned int kprobe_cpu = NR_CPUS;
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static DEFINE_SPINLOCK(kprobe_lock);
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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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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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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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INIT_HLIST_NODE(&p->hlist);
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if (get_kprobe(p->addr)) {
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ret = -EEXIST;
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goto out;
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}
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arch_copy_kprobe(p);
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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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p->opcode = *p->addr;
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*p->addr = BREAKPOINT_INSTRUCTION;
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flush_icache_range((unsigned long) p->addr,
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(unsigned long) p->addr + sizeof(kprobe_opcode_t));
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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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arch_remove_kprobe(p);
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spin_lock_irqsave(&kprobe_lock, flags);
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*p->addr = p->opcode;
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hlist_del(&p->hlist);
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flush_icache_range((unsigned long) p->addr,
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(unsigned long) p->addr + sizeof(kprobe_opcode_t));
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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;
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return register_kprobe(&jp->kp);
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}
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void unregister_jprobe(struct jprobe *jp)
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{
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unregister_kprobe(&jp->kp);
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}
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static int __init init_kprobes(void)
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{
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int i, err = 0;
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/* FIXME allocate the probe table, currently defined statically */
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/* initialize all list heads */
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for (i = 0; i < KPROBE_TABLE_SIZE; i++)
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INIT_HLIST_HEAD(&kprobe_table[i]);
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err = register_die_notifier(&kprobe_exceptions_nb);
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return err;
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}
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__initcall(init_kprobes);
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EXPORT_SYMBOL_GPL(register_kprobe);
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EXPORT_SYMBOL_GPL(unregister_kprobe);
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EXPORT_SYMBOL_GPL(register_jprobe);
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EXPORT_SYMBOL_GPL(unregister_jprobe);
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EXPORT_SYMBOL_GPL(jprobe_return);
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