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: systemtap<systemtap@sources.redhat.com>,
DLE<dle-develop@lists.sourceforge.net>,
Masami Hiramatsu <mhiramat@redhat.com>,
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 <mathieu.desnoyers@polymtl.ca>
Subject: [PATCH -tip v5 05/10] kprobes/x86: Boost probes when reentering
Date: Mon, 23 Nov 2009 23:19:00 -0000 [thread overview]
Message-ID: <20091123232156.22071.58619.stgit@dhcp-100-2-132.bos.redhat.com> (raw)
In-Reply-To: <20091123232115.22071.71558.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 <mathieu.desnoyers@polymtl.ca>
---
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 b6b75f1..85d88f6 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -403,18 +403,6 @@ 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)
{
@@ -427,19 +415,38 @@ 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) || defined(CONFIG_FREEZER)
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;
}
/*
@@ -453,11 +460,8 @@ 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
@@ -532,13 +536,13 @@ 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:[~2009-11-23 23:19 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-23 23:18 [PATCH -tip v5 00/10] kprobes: Kprobes jump optimization support Masami Hiramatsu
2009-11-23 23:18 ` [PATCH -tip v5 02/10] kprobes: Introduce generic insn_slot framework Masami Hiramatsu
2009-11-23 23:18 ` [PATCH -tip v5 01/10] kprobes/x86: Cleanup RELATIVEJUMP_INSTRUCTION to RELATIVEJUMP_OPCODE Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 10/10] [RFC] kprobes/x86: Use text_poke_fixup() for jump optimization Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 09/10] [RFC] x86: Introduce generic jump patching without stop_machine Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 08/10] kprobes: Add documents of jump optimization Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 07/10] kprobes/x86: Support kprobes jump optimization on x86 Masami Hiramatsu
2009-11-24 3:15 ` Frederic Weisbecker
2009-11-24 16:27 ` Jason Baron
2009-11-24 17:46 ` Masami Hiramatsu
2009-11-25 16:12 ` Masami Hiramatsu
2009-11-24 16:42 ` H. Peter Anvin
2009-11-24 17:01 ` Masami Hiramatsu
2009-11-23 23:19 ` Masami Hiramatsu [this message]
2009-11-23 23:19 ` [PATCH -tip v5 03/10] kprobes: Introduce kprobes jump optimization Masami Hiramatsu
2009-11-24 2:44 ` Frederic Weisbecker
2009-11-24 3:31 ` Frederic Weisbecker
2009-11-24 15:32 ` Masami Hiramatsu
2009-11-24 20:14 ` Frederic Weisbecker
2009-11-24 20:59 ` Masami Hiramatsu
2009-11-25 21:09 ` Steven Rostedt
2009-11-25 21:30 ` Masami Hiramatsu
2009-11-24 21:12 ` H. Peter Anvin
2009-11-24 15:31 ` Masami Hiramatsu
2009-11-24 19:45 ` Frederic Weisbecker
2009-11-24 21:15 ` Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 04/10] kprobes: Jump optimization sysctl interface Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 06/10] kprobes/x86: Cleanup save/restore registers Masami Hiramatsu
2009-11-24 2:51 ` Frederic Weisbecker
2009-11-24 15:36 ` Masami Hiramatsu
2009-11-24 20:19 ` Frederic Weisbecker
2009-11-24 15:40 ` Frank Ch. Eigler
2009-11-24 20:20 ` Frederic Weisbecker
2009-11-24 2:03 ` [PATCH -tip v5 00/10] kprobes: Kprobes jump optimization support Frederic Weisbecker
2009-11-24 3:20 ` Frederic Weisbecker
2009-11-24 7:53 ` Ingo Molnar
2009-11-24 16:03 ` 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=20091123232156.22071.58619.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=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=mathieu.desnoyers@polymtl.ca \
--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).