From: Masami Hiramatsu <mhiramat@redhat.com>
To: Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@elte.hu>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
lkml<linux-kernel@vger.kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Ingo Molnar <mingo@elte.hu>,
Jim Keniston <jkenisto@us.ibm.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Christoph Hellwig <hch@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Anders Kaseorg <andersk@ksplice.com>,
Tim Abbott <tabbott@ksplice.com>,
Andi Kleen <andi@firstfloor.org>,
Jason Baron <jbaron@redhat.com>,
Mathieu Desnoyers <compudj@krystal.dyndns.org>,
systemtap<systemtap@sources.redhat.com>,
DLE<dle-develop@lists.sourceforge.net>
Subject: [PATCH -tip v10 5/9] kprobes/x86: Boost probes when reentering
Date: Thu, 18 Feb 2010 22:06:00 -0000 [thread overview]
Message-ID: <20100218221328.19637.48613.stgit@dhcp-100-2-132.bos.redhat.com> (raw)
In-Reply-To: <20100218221247.19637.80088.stgit@dhcp-100-2-132.bos.redhat.com>
Integrate prepare_singlestep() into setup_singlestep() to boost up reenter
probes, if possible.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
---
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 */
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
next prev parent reply other threads:[~2010-02-18 22:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-18 22:06 [PATCH -tip v10 0/9] kprobes: Kprobes jump optimization support Masami Hiramatsu
2010-02-18 22:06 ` [PATCH -tip v10 2/9] kprobes: Introduce generic insn_slot framework Masami Hiramatsu
2010-02-18 22:06 ` [PATCH -tip v10 3/9] kprobes: Introduce kprobes jump optimization Masami Hiramatsu
2010-02-18 22:06 ` Masami Hiramatsu [this message]
2010-02-18 22:06 ` [PATCH -tip v10 1/9] kprobes/x86: Cleanup RELATIVEJUMP_INSTRUCTION to RELATIVEJUMP_OPCODE Masami Hiramatsu
2010-02-18 22:06 ` [PATCH -tip v10 4/9] kprobes: Jump optimization sysctl interface Masami Hiramatsu
2010-02-18 22:07 ` [PATCH -tip v10 6/9] kprobes/x86: Cleanup save/restore registers Masami Hiramatsu
2010-02-18 22:07 ` [PATCH -tip v10 7/9] x86: Add text_poke_smp for SMP cross modifying code Masami Hiramatsu
2010-02-18 22:07 ` [PATCH -tip v10 8/9] kprobes/x86: Support kprobes jump optimization on x86 Masami Hiramatsu
2010-02-18 22:07 ` [PATCH -tip v10 9/9] kprobes: Add documents of jump optimization Masami Hiramatsu
2010-02-22 23:14 ` [PATCH -tip v10 0/9] kprobes: Kprobes jump optimization support Masami Hiramatsu
2010-02-23 17:05 ` Frederic Weisbecker
2010-02-23 17:07 ` Steven Rostedt
2010-02-23 22:28 ` Masami Hiramatsu
2010-02-24 13:41 ` Masami Hiramatsu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100218221328.19637.48613.stgit@dhcp-100-2-132.bos.redhat.com \
--to=mhiramat@redhat.com \
--cc=ananth@in.ibm.com \
--cc=andersk@ksplice.com \
--cc=andi@firstfloor.org \
--cc=compudj@krystal.dyndns.org \
--cc=dle-develop@lists.sourceforge.net \
--cc=fweisbec@gmail.com \
--cc=hch@infradead.org \
--cc=hpa@zytor.com \
--cc=jbaron@redhat.com \
--cc=jkenisto@us.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=rostedt@goodmis.org \
--cc=srikar@linux.vnet.ibm.com \
--cc=systemtap@sources.redhat.com \
--cc=tabbott@ksplice.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).