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Commit e6584523 authored by Ananth N Mavinakayanahalli's avatar Ananth N Mavinakayanahalli Committed by Linus Torvalds
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[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: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: default avatarAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 66ff2d06

include/linux/kprobes.h

+22 −9
Original line number Diff line number Diff line
@@ -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_t *slot); 
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_instance *ri); 
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)

{

kernel/kprobes.c

+28 −15
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; 


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 @@ 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)

{
@@ -213,11 +224,11 @@ static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) 


	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 @@ static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, 


	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 void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, 
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_fault_handler(struct kprobe *p, struct pt_regs *regs, 


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)