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[PATCH] kprobes: Temporary disarming of reentrant probe for ppc64 

This patch includes ppc64 architecture specific changes to support temporary
disarming on reentrancy of probes.

Signed-of-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Prasanna S Panchamukhi 2005-06-23 00:09:38 -07:00 committed by Linus Torvalds
parent aa3d7e3d78
commit 42cc20600a
1 changed files with 38 additions and 8 deletions
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46
arch/ppc64/kernel/kprobes.c
View File

@ -36,12 +36,10 @@
#include <asm/kdebug.h>
#include <asm/sstep.h>
/* kprobe_status settings */
#define KPROBE_HIT_ACTIVE 0x00000001
#define KPROBE_HIT_SS 0x00000002
static struct kprobe *current_kprobe;
static unsigned long kprobe_status, kprobe_saved_msr;
static struct kprobe *kprobe_prev;
static unsigned long kprobe_status_prev, kprobe_saved_msr_prev;
static struct pt_regs jprobe_saved_regs;
int arch_prepare_kprobe(struct kprobe *p)
@ -93,6 +91,20 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
regs->nip = (unsigned long)&p->ainsn.insn;
}
static inline void save_previous_kprobe(void)
{
kprobe_prev = current_kprobe;
kprobe_status_prev = kprobe_status;
kprobe_saved_msr_prev = kprobe_saved_msr;
}
static inline void restore_previous_kprobe(void)
{
current_kprobe = kprobe_prev;
kprobe_status = kprobe_status_prev;
kprobe_saved_msr = kprobe_saved_msr_prev;
}
static inline int kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
@ -111,9 +123,19 @@ static inline int kprobe_handler(struct pt_regs *regs)
unlock_kprobes();
goto no_kprobe;
}
arch_disarm_kprobe(p);
regs->nip = (unsigned long)p->addr;
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();
current_kprobe = p;
kprobe_saved_msr = regs->msr;
p->nmissed++;
prepare_singlestep(p, regs);
kprobe_status = KPROBE_REENTER;
return 1;
} else {
p = current_kprobe;
if (p->break_handler && p->break_handler(p, regs)) {
@ -195,13 +217,21 @@ 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);
regs->msr |= kprobe_saved_msr;
/*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();
/*