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Commit e539c233 authored by Prasanna S Panchamukhi's avatar Prasanna S Panchamukhi Committed by Linus Torvalds
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[PATCH] kprobes: Temporary disarming of reentrant probe for sparc64 



This patch includes sparc64 architecture specific changes to support temporary
disarming on reentrancy of probes.

Signed-of-by: default avatarPrasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 42cc2060

arch/sparc64/kernel/kprobes.c

+49 −13
Original line number Diff line number Diff line
@@ -65,19 +65,40 @@ void arch_remove_kprobe(struct kprobe *p) 
{

}



/* kprobe_status settings */

#define KPROBE_HIT_ACTIVE	0x00000001

#define KPROBE_HIT_SS		0x00000002



static struct kprobe *current_kprobe;

static unsigned long current_kprobe_orig_tnpc;

static unsigned long current_kprobe_orig_tstate_pil;

static unsigned int kprobe_status;

static struct kprobe *kprobe_prev;

static unsigned long kprobe_orig_tnpc_prev;

static unsigned long kprobe_orig_tstate_pil_prev;

static unsigned int kprobe_status_prev;



static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)

static inline void save_previous_kprobe(void)

{

	kprobe_status_prev = kprobe_status;

	kprobe_orig_tnpc_prev = current_kprobe_orig_tnpc;

	kprobe_orig_tstate_pil_prev = current_kprobe_orig_tstate_pil;

	kprobe_prev = current_kprobe;

}



static inline void restore_previous_kprobe(void)

{

	kprobe_status = kprobe_status_prev;

	current_kprobe_orig_tnpc = kprobe_orig_tnpc_prev;

	current_kprobe_orig_tstate_pil = kprobe_orig_tstate_pil_prev;

	current_kprobe = kprobe_prev;

}



static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs)

{

	current_kprobe_orig_tnpc = regs->tnpc;

	current_kprobe_orig_tstate_pil = (regs->tstate & TSTATE_PIL);

	current_kprobe = p;

}



static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)

{

	regs->tstate |= TSTATE_PIL;



	/*single step inline, if it a breakpoint instruction*/
@@ -110,12 +131,18 @@ static int kprobe_handler(struct pt_regs *regs) 
				unlock_kprobes();

				goto no_kprobe;

			}

			arch_disarm_kprobe(p);

			regs->tpc = (unsigned long) p->addr;

			regs->tnpc = current_kprobe_orig_tnpc;

			regs->tstate = ((regs->tstate & ~TSTATE_PIL) |

					current_kprobe_orig_tstate_pil);

			ret = 1;

			/* We have reentered the kprobe_handler(), since

			 * another probe was hit while within the handler.

			 * We here save the original kprobes variables and

			 * just single step on the instruction of the new probe

			 * without calling any user handlers.

			 */

			save_previous_kprobe();

			set_current_kprobe(p, regs);

			p->nmissed++;

			kprobe_status = KPROBE_REENTER;

			prepare_singlestep(p, regs);

			return 1;

		} else {

			p = current_kprobe;

			if (p->break_handler && p->break_handler(p, regs))
@@ -143,8 +170,8 @@ static int kprobe_handler(struct pt_regs *regs) 
		goto no_kprobe;

	}



	set_current_kprobe(p, regs);

	kprobe_status = KPROBE_HIT_ACTIVE;

	current_kprobe = p;

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

		return 1;
@@ -250,12 +277,20 @@ static inline int post_kprobe_handler(struct pt_regs *regs) 
	if (!kprobe_running())

		return 0;



	if (current_kprobe->post_handler)

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

		kprobe_status = KPROBE_HIT_SSDONE;

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

	}



	resume_execution(current_kprobe, regs);



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

	if (kprobe_status == KPROBE_REENTER) {

		restore_previous_kprobe();

		goto out;

	}

	unlock_kprobes();

out:

	preempt_enable_no_resched();



	return 1;
@@ -397,3 +432,4 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) 
	}

	return 0;

}