From: Ananth N Mavinakayanahalli <[email protected]>
Changes to the base kprobe infrastructure to track kprobe execution on a
per-cpu basis.
Signed-off-by: Ananth N Mavinakayanahalli <[email protected]>
Signed-off-by: Anil S Keshavamurthy <[email protected]>
---
include/linux/kprobes.h | 31 ++++++++++++++++++++++---------
kernel/kprobes.c | 43 ++++++++++++++++++++++++++++---------------
2 files changed, 50 insertions(+), 24 deletions(-)
Index: linux-2.6.14-rc3/include/linux/kprobes.h
===================================================================
--- linux-2.6.14-rc3.orig/include/linux/kprobes.h 2005-09-30 17:17:35.000000000 -0400
+++ linux-2.6.14-rc3/include/linux/kprobes.h 2005-10-05 15:25:39.000000000 -0400
@@ -33,6 +33,7 @@
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/smp.h>
+#include <linux/percpu.h>
#include <asm/kprobes.h>
@@ -106,6 +107,9 @@ struct jprobe {
kprobe_opcode_t *entry; /* probe handling code to jump to */
};
+DECLARE_PER_CPU(struct kprobe *, current_kprobe);
+DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
#ifdef ARCH_SUPPORTS_KRETPROBES
extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs);
#else /* ARCH_SUPPORTS_KRETPROBES */
@@ -146,13 +150,6 @@ struct kretprobe_instance {
void lock_kprobes(void);
void unlock_kprobes(void);
-/* kprobe running now on this CPU? */
-static inline int kprobe_running(void)
-{
- extern unsigned int kprobe_cpu;
- return kprobe_cpu == smp_processor_id();
-}
-
extern int arch_prepare_kprobe(struct kprobe *p);
extern void arch_copy_kprobe(struct kprobe *p);
extern void arch_arm_kprobe(struct kprobe *p);
@@ -167,6 +164,22 @@ extern void free_insn_slot(kprobe_opcode
struct kprobe *get_kprobe(void *addr);
struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
+/* kprobe_running() will just return the current_kprobe on this CPU */
+static inline struct kprobe *kprobe_running(void)
+{
+ return (__get_cpu_var(current_kprobe));
+}
+
+static inline void reset_current_kprobe(void)
+{
+ __get_cpu_var(current_kprobe) = NULL;
+}
+
+static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
+{
+ return (&__get_cpu_var(kprobe_ctlblk));
+}
+
int register_kprobe(struct kprobe *p);
void unregister_kprobe(struct kprobe *p);
int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
@@ -183,9 +196,9 @@ void add_rp_inst(struct kretprobe_instan
void kprobe_flush_task(struct task_struct *tk);
void recycle_rp_inst(struct kretprobe_instance *ri);
#else /* CONFIG_KPROBES */
-static inline int kprobe_running(void)
+static inline struct kprobe *kprobe_running(void)
{
- return 0;
+ return NULL;
}
static inline int register_kprobe(struct kprobe *p)
{
Index: linux-2.6.14-rc3/kernel/kprobes.c
===================================================================
--- linux-2.6.14-rc3.orig/kernel/kprobes.c 2005-09-30 17:17:35.000000000 -0400
+++ linux-2.6.14-rc3/kernel/kprobes.c 2005-10-05 15:25:39.000000000 -0400
@@ -50,7 +50,7 @@ static struct hlist_head kretprobe_inst_
unsigned int kprobe_cpu = NR_CPUS;
static DEFINE_SPINLOCK(kprobe_lock);
-static struct kprobe *curr_kprobe;
+static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
/*
* kprobe->ainsn.insn points to the copy of the instruction to be
@@ -187,6 +187,17 @@ void __kprobes unlock_kprobes(void)
local_irq_restore(flags);
}
+/* We have preemption disabled.. so it is safe to use __ versions */
+static inline void set_kprobe_instance(struct kprobe *kp)
+{
+ __get_cpu_var(kprobe_instance) = kp;
+}
+
+static inline void reset_kprobe_instance(void)
+{
+ __get_cpu_var(kprobe_instance) = NULL;
+}
+
/* You have to be holding the kprobe_lock */
struct kprobe __kprobes *get_kprobe(void *addr)
{
@@ -212,11 +223,11 @@ static int __kprobes aggr_pre_handler(st
list_for_each_entry(kp, &p->list, list) {
if (kp->pre_handler) {
- curr_kprobe = kp;
+ set_kprobe_instance(kp);
if (kp->pre_handler(kp, regs))
return 1;
}
- curr_kprobe = NULL;
+ reset_kprobe_instance();
}
return 0;
}
@@ -228,9 +239,9 @@ static void __kprobes aggr_post_handler(
list_for_each_entry(kp, &p->list, list) {
if (kp->post_handler) {
- curr_kprobe = kp;
+ set_kprobe_instance(kp);
kp->post_handler(kp, regs, flags);
- curr_kprobe = NULL;
+ reset_kprobe_instance();
}
}
return;
@@ -239,12 +250,14 @@ static void __kprobes aggr_post_handler(
static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
int trapnr)
{
+ struct kprobe *cur = __get_cpu_var(kprobe_instance);
+
/*
* if we faulted "during" the execution of a user specified
* probe handler, invoke just that probe's fault handler
*/
- if (curr_kprobe && curr_kprobe->fault_handler) {
- if (curr_kprobe->fault_handler(curr_kprobe, regs, trapnr))
+ if (cur && cur->fault_handler) {
+ if (cur->fault_handler(cur, regs, trapnr))
return 1;
}
return 0;
@@ -252,15 +265,15 @@ static int __kprobes aggr_fault_handler(
static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
{
- struct kprobe *kp = curr_kprobe;
- if (curr_kprobe && kp->break_handler) {
- if (kp->break_handler(kp, regs)) {
- curr_kprobe = NULL;
- return 1;
- }
+ struct kprobe *cur = __get_cpu_var(kprobe_instance);
+ int ret = 0;
+
+ if (cur && cur->break_handler) {
+ if (cur->break_handler(cur, regs))
+ ret = 1;
}
- curr_kprobe = NULL;
- return 0;
+ reset_kprobe_instance();
+ return ret;
}
struct kretprobe_instance __kprobes *get_free_rp_inst(struct kretprobe *rp)
-
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