lkml.org 
[lkml]   [2005]   [May]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 5/5] 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: Prasanna S Panchamukhi <prasanna@in.ibm.com>
---


---

linux-2.6.12-rc4-mm2-prasanna/arch/sparc64/kernel/kprobes.c | 62 +++++++++---
1 files changed, 49 insertions(+), 13 deletions(-)

diff -puN arch/sparc64/kernel/kprobes.c~kprobes-temporary-disarming-on-reentrancy-sparc64 arch/sparc64/kernel/kprobes.c
--- linux-2.6.12-rc4-mm2/arch/sparc64/kernel/kprobes.c~kprobes-temporary-disarming-on-reentrancy-sparc64 2005-05-24 15:30:47.000000000 +0530
+++ linux-2.6.12-rc4-mm2-prasanna/arch/sparc64/kernel/kprobes.c 2005-05-24 15:30:47.000000000 +0530
@@ -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
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
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(st
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
}
return 0;
}
+
_
--

Prasanna S Panchamukhi
Linux Technology Center
India Software Labs, IBM Bangalore
Ph: 91-80-25044636
<prasanna@in.ibm.com>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-05-24 12:40    [W:0.076 / U:0.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site