Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8a5c4dc5 authored by Ananth N Mavinakayanahalli's avatar Ananth N Mavinakayanahalli Committed by Linus Torvalds
Browse files

[PATCH] Kprobes: Track kprobe on a per_cpu basis - ia64 changes 



IA64 changes to track kprobe execution on a per-cpu basis.  We now track the
kprobe state machine independently on each cpu using an arch specific kprobe
control block.

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 9a0e3a86

arch/ia64/kernel/kprobes.c

+45 −38
Original line number Diff line number Diff line
@@ -38,13 +38,8 @@ 


extern void jprobe_inst_return(void);



/* kprobe_status settings */

#define KPROBE_HIT_ACTIVE	0x00000001

#define KPROBE_HIT_SS		0x00000002



static struct kprobe *current_kprobe, *kprobe_prev;

static unsigned long kprobe_status, kprobe_status_prev;

static struct pt_regs jprobe_saved_regs;

DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;

DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);



enum instruction_type {A, I, M, F, B, L, X, u};

static enum instruction_type bundle_encoding[32][3] = {
@@ -313,21 +308,22 @@ static int __kprobes valid_kprobe_addr(int template, int slot, 
	return 0;

}



static inline void save_previous_kprobe(void)

static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)

{

	kprobe_prev = current_kprobe;

	kprobe_status_prev = kprobe_status;

	kcb->prev_kprobe.kp = kprobe_running();

	kcb->prev_kprobe.status = kcb->kprobe_status;

}



static inline void restore_previous_kprobe(void)

static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb)

{

	current_kprobe = kprobe_prev;

	kprobe_status = kprobe_status_prev;

	__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;

	kcb->kprobe_status = kcb->prev_kprobe.status;

}



static inline void set_current_kprobe(struct kprobe *p)

static inline void set_current_kprobe(struct kprobe *p,

			struct kprobe_ctlblk *kcb)

{

	current_kprobe = p;

	__get_cpu_var(current_kprobe) = p;

}



static void kretprobe_trampoline(void)
@@ -389,6 +385,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) 
	BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));

	regs->cr_iip = orig_ret_address;



	reset_current_kprobe();

	unlock_kprobes();

	preempt_enable_no_resched();
@@ -606,12 +603,13 @@ static int __kprobes pre_kprobes_handler(struct die_args *args) 
	int ret = 0;

	struct pt_regs *regs = args->regs;

	kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();



	/* Handle recursion cases */

	if (kprobe_running()) {

		p = get_kprobe(addr);

		if (p) {

			if ( (kprobe_status == KPROBE_HIT_SS) &&

			if ((kcb->kprobe_status == KPROBE_HIT_SS) &&

	 		     (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {

  				ia64_psr(regs)->ss = 0;

				unlock_kprobes();
@@ -623,17 +621,17 @@ static int __kprobes pre_kprobes_handler(struct die_args *args) 
			 * just single step on the instruction of the new probe

			 * without calling any user handlers.

			 */

			save_previous_kprobe();

			set_current_kprobe(p);

			save_previous_kprobe(kcb);

			set_current_kprobe(p, kcb);

			p->nmissed++;

			prepare_ss(p, regs);

			kprobe_status = KPROBE_REENTER;

			kcb->kprobe_status = KPROBE_REENTER;

			return 1;

		} else if (args->err == __IA64_BREAK_JPROBE) {

			/*

			 * jprobe instrumented function just completed

			 */

			p = current_kprobe;

			p = __get_cpu_var(current_kprobe);

			if (p->break_handler && p->break_handler(p, regs)) {

				goto ss_probe;

			}
@@ -668,8 +666,8 @@ static int __kprobes pre_kprobes_handler(struct die_args *args) 
	 * in post_kprobes_handler()

	 */

	preempt_disable();

	kprobe_status = KPROBE_HIT_ACTIVE;

	set_current_kprobe(p);

	set_current_kprobe(p, kcb);

	kcb->kprobe_status = KPROBE_HIT_ACTIVE;



	if (p->pre_handler && p->pre_handler(p, regs))

		/*
@@ -681,7 +679,7 @@ static int __kprobes pre_kprobes_handler(struct die_args *args) 


ss_probe:

	prepare_ss(p, regs);

	kprobe_status = KPROBE_HIT_SS;

	kcb->kprobe_status = KPROBE_HIT_SS;

	return 1;



no_kprobe:
@@ -690,22 +688,25 @@ static int __kprobes pre_kprobes_handler(struct die_args *args) 


static int __kprobes post_kprobes_handler(struct pt_regs *regs)

{

	if (!kprobe_running())

	struct kprobe *cur = kprobe_running();

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();



	if (!cur)

		return 0;



	if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {

		kprobe_status = KPROBE_HIT_SSDONE;

		current_kprobe->post_handler(current_kprobe, regs, 0);

	if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {

		kcb->kprobe_status = KPROBE_HIT_SSDONE;

		cur->post_handler(cur, regs, 0);

	}



	resume_execution(current_kprobe, regs);

	resume_execution(cur, regs);



	/*Restore back the original saved kprobes variables and continue. */

	if (kprobe_status == KPROBE_REENTER) {

		restore_previous_kprobe();

	if (kcb->kprobe_status == KPROBE_REENTER) {

		restore_previous_kprobe(kcb);

		goto out;

	}



	reset_current_kprobe();

	unlock_kprobes();



out:
@@ -715,15 +716,18 @@ static int __kprobes post_kprobes_handler(struct pt_regs *regs) 


static int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)

{

	if (!kprobe_running())

	struct kprobe *cur = kprobe_running();

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();



	if (!cur)

		return 0;



	if (current_kprobe->fault_handler &&

	    current_kprobe->fault_handler(current_kprobe, regs, trapnr))

	if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))

		return 1;



	if (kprobe_status & KPROBE_HIT_SS) {

		resume_execution(current_kprobe, regs);

	if (kcb->kprobe_status & KPROBE_HIT_SS) {

		resume_execution(cur, regs);

		reset_current_kprobe();

		unlock_kprobes();

		preempt_enable_no_resched();

	}
@@ -761,9 +765,10 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) 
{

	struct jprobe *jp = container_of(p, struct jprobe, kp);

	unsigned long addr = ((struct fnptr *)(jp->entry))->ip;

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();



	/* save architectural state */

	jprobe_saved_regs = *regs;

	kcb->jprobe_saved_regs = *regs;



	/* after rfi, execute the jprobe instrumented function */

	regs->cr_iip = addr & ~0xFULL;
@@ -781,7 +786,9 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) 


int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)

{

	*regs = jprobe_saved_regs;

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();



	*regs = kcb->jprobe_saved_regs;

	return 1;

}

include/asm-ia64/kprobes.h

+13 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
 */

#include <linux/types.h>

#include <linux/ptrace.h>

#include <linux/percpu.h>

#include <asm/break.h>



#define MAX_INSN_SIZE   16
@@ -62,6 +63,18 @@ typedef struct _bundle { 
	} quad1;

} __attribute__((__aligned__(16)))  bundle_t;



struct prev_kprobe {

	struct kprobe *kp;

	unsigned long status;

};



/* per-cpu kprobe control block */

struct kprobe_ctlblk {

	unsigned long kprobe_status;

	struct pt_regs jprobe_saved_regs;

	struct prev_kprobe prev_kprobe;

};



#define JPROBE_ENTRY(pentry)	(kprobe_opcode_t *)pentry



#define ARCH_SUPPORTS_KRETPROBES