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Message-ID: <tip-0f94eb634ef7af736dee5639aac1c2fe9635d089@git.kernel.org>
Date: Thu, 25 Feb 2010 19:29:01 GMT
From: tip-bot for Masami Hiramatsu <mhiramat@...hat.com>
To: linux-tip-commits@...r.kernel.org
Cc: mingo@...hat.com, andersk@...lice.com, fweisbec@...il.com,
dle-develop@...ts.sourceforge.net, rostedt@...dmis.org,
compudj@...stal.dyndns.org, jbaron@...hat.com, tglx@...utronix.de,
mhiramat@...hat.com, systemtap@...rces.redhat.com,
linux-kernel@...r.kernel.org, hpa@...or.com, jkenisto@...ibm.com,
andi@...stfloor.org, tabbott@...lice.com, hch@...radead.org,
ananth@...ibm.com, srikar@...ux.vnet.ibm.com, mingo@...e.hu
Subject: [tip:perf/probes] kprobes/x86: Boost probes when reentering
Commit-ID: 0f94eb634ef7af736dee5639aac1c2fe9635d089
Gitweb: http://git.kernel.org/tip/0f94eb634ef7af736dee5639aac1c2fe9635d089
Author: Masami Hiramatsu <mhiramat@...hat.com>
AuthorDate: Thu, 25 Feb 2010 08:34:23 -0500
Committer: Ingo Molnar <mingo@...e.hu>
CommitDate: Thu, 25 Feb 2010 17:49:25 +0100
kprobes/x86: Boost probes when reentering
Integrate prepare_singlestep() into setup_singlestep() to boost
up reenter probes, if possible.
Signed-off-by: Masami Hiramatsu <mhiramat@...hat.com>
Cc: systemtap <systemtap@...rces.redhat.com>
Cc: DLE <dle-develop@...ts.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@...ibm.com>
Cc: Jim Keniston <jkenisto@...ibm.com>
Cc: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@...radead.org>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Anders Kaseorg <andersk@...lice.com>
Cc: Tim Abbott <tabbott@...lice.com>
Cc: Andi Kleen <andi@...stfloor.org>
Cc: Jason Baron <jbaron@...hat.com>
Cc: Mathieu Desnoyers <compudj@...stal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Ananth N Mavinakayanahalli <ananth@...ibm.com>
LKML-Reference: <20100225133423.6725.12071.stgit@...alhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
arch/x86/kernel/kprobes.c | 48 ++++++++++++++++++++++++--------------------
1 files changed, 26 insertions(+), 22 deletions(-)
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 15177cd..c69bb65 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -406,18 +406,6 @@ static void __kprobes restore_btf(void)
update_debugctlmsr(current->thread.debugctlmsr);
}
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
-{
- clear_btf();
- regs->flags |= X86_EFLAGS_TF;
- regs->flags &= ~X86_EFLAGS_IF;
- /* single step inline if the instruction is an int3 */
- if (p->opcode == BREAKPOINT_INSTRUCTION)
- regs->ip = (unsigned long)p->addr;
- else
- regs->ip = (unsigned long)p->ainsn.insn;
-}
-
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
@@ -430,19 +418,38 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
}
static void __kprobes setup_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
+ struct kprobe_ctlblk *kcb, int reenter)
{
#if !defined(CONFIG_PREEMPT)
if (p->ainsn.boostable == 1 && !p->post_handler) {
/* Boost up -- we can execute copied instructions directly */
- reset_current_kprobe();
+ if (!reenter)
+ reset_current_kprobe();
+ /*
+ * Reentering boosted probe doesn't reset current_kprobe,
+ * nor set current_kprobe, because it doesn't use single
+ * stepping.
+ */
regs->ip = (unsigned long)p->ainsn.insn;
preempt_enable_no_resched();
return;
}
#endif
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_HIT_SS;
+ if (reenter) {
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_REENTER;
+ } else
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ /* Prepare real single stepping */
+ clear_btf();
+ regs->flags |= X86_EFLAGS_TF;
+ regs->flags &= ~X86_EFLAGS_IF;
+ /* single step inline if the instruction is an int3 */
+ if (p->opcode == BREAKPOINT_INSTRUCTION)
+ regs->ip = (unsigned long)p->addr;
+ else
+ regs->ip = (unsigned long)p->ainsn.insn;
}
/*
@@ -456,11 +463,8 @@ static int __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
switch (kcb->kprobe_status) {
case KPROBE_HIT_SSDONE:
case KPROBE_HIT_ACTIVE:
- save_previous_kprobe(kcb);
- set_current_kprobe(p, regs, kcb);
kprobes_inc_nmissed_count(p);
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_REENTER;
+ setup_singlestep(p, regs, kcb, 1);
break;
case KPROBE_HIT_SS:
/* A probe has been hit in the codepath leading up to, or just
@@ -535,13 +539,13 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
* more here.
*/
if (!p->pre_handler || !p->pre_handler(p, regs))
- setup_singlestep(p, regs, kcb);
+ setup_singlestep(p, regs, kcb, 0);
return 1;
}
} else if (kprobe_running()) {
p = __get_cpu_var(current_kprobe);
if (p->break_handler && p->break_handler(p, regs)) {
- setup_singlestep(p, regs, kcb);
+ setup_singlestep(p, regs, kcb, 0);
return 1;
}
} /* else: not a kprobe fault; let the kernel handle it */
--
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