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-rw-r--r--kernel/kprobes.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
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--- /dev/null
+++ b/kernel/kprobes.c
@@ -0,0 +1,157 @@
+/*
+ * Kernel Probes (KProbes)
+ * kernel/kprobes.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
+ * Probes initial implementation (includes suggestions from
+ * Rusty Russell).
+ * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
+ * hlists and exceptions notifier as suggested by Andi Kleen.
+ * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
+ * interface to access function arguments.
+ * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
+ * exceptions notifier to be first on the priority list.
+ */
+#include <linux/kprobes.h>
+#include <linux/spinlock.h>
+#include <linux/hash.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <asm/cacheflush.h>
+#include <asm/errno.h>
+#include <asm/kdebug.h>
+
+#define KPROBE_HASH_BITS 6
+#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
+
+static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
+
+unsigned int kprobe_cpu = NR_CPUS;
+static DEFINE_SPINLOCK(kprobe_lock);
+
+/* Locks kprobe: irqs must be disabled */
+void lock_kprobes(void)
+{
+ spin_lock(&kprobe_lock);
+ kprobe_cpu = smp_processor_id();
+}
+
+void unlock_kprobes(void)
+{
+ kprobe_cpu = NR_CPUS;
+ spin_unlock(&kprobe_lock);
+}
+
+/* You have to be holding the kprobe_lock */
+struct kprobe *get_kprobe(void *addr)
+{
+ struct hlist_head *head;
+ struct hlist_node *node;
+
+ head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
+ hlist_for_each(node, head) {
+ struct kprobe *p = hlist_entry(node, struct kprobe, hlist);
+ if (p->addr == addr)
+ return p;
+ }
+ return NULL;
+}
+
+int register_kprobe(struct kprobe *p)
+{
+ int ret = 0;
+ unsigned long flags = 0;
+
+ if ((ret = arch_prepare_kprobe(p)) != 0) {
+ goto rm_kprobe;
+ }
+ spin_lock_irqsave(&kprobe_lock, flags);
+ INIT_HLIST_NODE(&p->hlist);
+ if (get_kprobe(p->addr)) {
+ ret = -EEXIST;
+ goto out;
+ }
+ arch_copy_kprobe(p);
+
+ hlist_add_head(&p->hlist,
+ &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
+
+ p->opcode = *p->addr;
+ *p->addr = BREAKPOINT_INSTRUCTION;
+ flush_icache_range((unsigned long) p->addr,
+ (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+out:
+ spin_unlock_irqrestore(&kprobe_lock, flags);
+rm_kprobe:
+ if (ret == -EEXIST)
+ arch_remove_kprobe(p);
+ return ret;
+}
+
+void unregister_kprobe(struct kprobe *p)
+{
+ unsigned long flags;
+ arch_remove_kprobe(p);
+ spin_lock_irqsave(&kprobe_lock, flags);
+ *p->addr = p->opcode;
+ hlist_del(&p->hlist);
+ flush_icache_range((unsigned long) p->addr,
+ (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+ spin_unlock_irqrestore(&kprobe_lock, flags);
+}
+
+static struct notifier_block kprobe_exceptions_nb = {
+ .notifier_call = kprobe_exceptions_notify,
+ .priority = 0x7fffffff /* we need to notified first */
+};
+
+int register_jprobe(struct jprobe *jp)
+{
+ /* 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);
+}
+
+void unregister_jprobe(struct jprobe *jp)
+{
+ unregister_kprobe(&jp->kp);
+}
+
+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]);
+
+ 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);