[PATCH] Kprobes: Track kprobe on a per_cpu basis - base changes
Changes to the base kprobe infrastructure to track kprobe execution on a
per-cpu basis.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index ce4915d..6da8f9b3 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -51,7 +51,7 @@
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
@@ -188,6 +188,17 @@
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)
{
@@ -213,11 +224,11 @@
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;
}
@@ -229,9 +240,9 @@
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;
@@ -240,12 +251,14 @@
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;
@@ -253,15 +266,15 @@
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)
