From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Sandeepa Prabhu <sandeepa.prabhu@linaro.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
x86@kernel.org, Steven Rostedt <rostedt@goodmis.org>,
fche@redhat.com, mingo@redhat.com, systemtap@sourceware.org,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH -tip v8 23/26] kprobes/x86: Remove unneeded preempt_disable/enable in interrupt handlers
Date: Wed, 05 Mar 2014 12:01:00 -0000 [thread overview]
Message-ID: <20140305120124.22766.92183.stgit@ltc230.yrl.intra.hitachi.co.jp> (raw)
In-Reply-To: <20140305115843.22766.8355.stgit@ltc230.yrl.intra.hitachi.co.jp>
Since the int3 itself disables the local_irq and kprobes
keeps it disabled while the single step has done, the
kernel preemption never happen while processing a kprobe.
This means that we don't need to disable/enable preemption.
Also, this changes kprobe_int3_handler to use goto-out style.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
arch/x86/kernel/kprobes/core.c | 24 +++++++-----------------
1 file changed, 7 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 4767fda..8ef676f 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -506,7 +506,6 @@ static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
* stepping.
*/
regs->ip = (unsigned long)p->ainsn.insn;
- preempt_enable_no_resched();
return;
}
#endif
@@ -575,13 +574,6 @@ int kprobe_int3_handler(struct pt_regs *regs)
struct kprobe_ctlblk *kcb;
addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
- /*
- * We don't want to be preempted for the entire
- * duration of kprobe processing. We conditionally
- * re-enable preemption at the end of this function,
- * and also in reenter_kprobe() and setup_singlestep().
- */
- preempt_disable();
kcb = get_kprobe_ctlblk();
p = get_kprobe(addr);
@@ -589,7 +581,7 @@ int kprobe_int3_handler(struct pt_regs *regs)
if (p) {
if (kprobe_running()) {
if (reenter_kprobe(p, regs, kcb))
- return 1;
+ goto handled;
} else {
set_current_kprobe(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
@@ -604,7 +596,7 @@ int kprobe_int3_handler(struct pt_regs *regs)
*/
if (!p->pre_handler || !p->pre_handler(p, regs))
setup_singlestep(p, regs, kcb, 0);
- return 1;
+ goto handled;
}
} else if (*addr != BREAKPOINT_INSTRUCTION) {
/*
@@ -617,19 +609,20 @@ int kprobe_int3_handler(struct pt_regs *regs)
* the original instruction.
*/
regs->ip = (unsigned long)addr;
- preempt_enable_no_resched();
- return 1;
+ goto handled;
} else if (kprobe_running()) {
p = __this_cpu_read(current_kprobe);
if (p->break_handler && p->break_handler(p, regs)) {
if (!skip_singlestep(p, regs, kcb))
setup_singlestep(p, regs, kcb, 0);
- return 1;
+ goto handled;
}
} /* else: not a kprobe fault; let the kernel handle it */
- preempt_enable_no_resched();
return 0;
+
+handled:
+ return 1;
}
NOKPROBE_SYMBOL(kprobe_int3_handler);
@@ -894,7 +887,6 @@ int kprobe_debug_handler(struct pt_regs *regs)
}
reset_current_kprobe();
out:
- preempt_enable_no_resched();
/*
* if somebody else is singlestepping across a probe point, flags
@@ -927,7 +919,6 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
restore_previous_kprobe(kcb);
else
reset_current_kprobe();
- preempt_enable_no_resched();
} else if (kcb->kprobe_status == KPROBE_HIT_ACTIVE ||
kcb->kprobe_status == KPROBE_HIT_SSDONE) {
/*
@@ -1058,7 +1049,6 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
memcpy((kprobe_opcode_t *)(kcb->jprobe_saved_sp),
kcb->jprobes_stack,
MIN_STACK_SIZE(kcb->jprobe_saved_sp));
- preempt_enable_no_resched();
return 1;
}
return 0;
next prev parent reply other threads:[~2014-03-05 12:01 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-05 11:58 [PATCH -tip v8 00/26] kprobes: introduce NOKPROBE_SYMBOL, bugfixes and scalbility efforts Masami Hiramatsu
2014-03-05 11:59 ` [PATCH -tip v8 06/26] [BUGFIX] x86: Prohibit probing on native_set_debugreg/load_idt Masami Hiramatsu
2014-03-22 0:53 ` Steven Rostedt
2014-03-05 11:59 ` [PATCH -tip v8 01/26] [BUGFIX]kprobes/x86: Fix page-fault handling logic Masami Hiramatsu
2014-03-21 21:39 ` Steven Rostedt
2014-03-24 1:10 ` Masami Hiramatsu
2014-03-05 11:59 ` [PATCH -tip v8 03/26] kprobes: Prohibit probing on .entry.text code Masami Hiramatsu
2014-03-21 22:04 ` Steven Rostedt
2014-03-24 1:48 ` Masami Hiramatsu
2014-03-24 18:54 ` Steven Rostedt
2014-03-24 18:55 ` Steven Rostedt
2014-03-05 11:59 ` [PATCH -tip v8 08/26] kprobes/x86: Call exception handlers directly from do_int3/do_debug Masami Hiramatsu
2014-03-22 1:05 ` Steven Rostedt
2014-03-24 8:47 ` Masami Hiramatsu
2014-03-24 18:58 ` Steven Rostedt
2014-03-05 11:59 ` [PATCH -tip v8 04/26] kprobes: Introduce NOKPROBE_SYMBOL() macro for blacklist Masami Hiramatsu
2014-03-22 0:49 ` Steven Rostedt
2014-03-26 7:04 ` Masami Hiramatsu
2014-03-05 11:59 ` [PATCH -tip v8 05/26] [BUGFIX] kprobes/x86: Prohibit probing on debug_stack_* Masami Hiramatsu
2014-03-22 0:50 ` Steven Rostedt
2014-03-05 11:59 ` [PATCH -tip v8 02/26] kprobes/x86: Allow to handle reentered kprobe on singlestepping Masami Hiramatsu
2014-03-21 21:44 ` Steven Rostedt
2014-03-24 10:07 ` Masami Hiramatsu
2014-03-05 11:59 ` [PATCH -tip v8 07/26] [BUGFIX] x86: Prohibit probing on thunk functions and restore Masami Hiramatsu
2014-03-22 1:00 ` Steven Rostedt
2014-03-24 3:04 ` Masami Hiramatsu
2014-03-24 18:56 ` Steven Rostedt
2014-03-05 11:59 ` [PATCH -tip v8 09/26] x86: Call exception_enter after kprobes handled Masami Hiramatsu
2014-03-24 19:31 ` Steven Rostedt
2014-03-05 12:00 ` [PATCH -tip v8 16/26] ftrace/kprobes: Use NOKPROBE_SYMBOL macro in ftrace Masami Hiramatsu
2014-03-24 20:10 ` Steven Rostedt
2014-03-25 10:31 ` Masami Hiramatsu
2014-03-05 12:00 ` [PATCH -tip v8 10/26] kprobes/x86: Allow probe on some kprobe preparation functions Masami Hiramatsu
2014-03-24 19:36 ` Steven Rostedt
2014-03-25 9:20 ` Masami Hiramatsu
2014-03-27 5:50 ` Masami Hiramatsu
2014-03-05 12:00 ` [PATCH -tip v8 15/26] kprobes: Use NOKPROBE_SYMBOL macro instead of __kprobes Masami Hiramatsu
2014-03-24 19:46 ` Steven Rostedt
2014-03-05 12:00 ` [PATCH -tip v8 17/26] notifier: Use NOKPROBE_SYMBOL macro in notifier Masami Hiramatsu
2014-03-24 20:12 ` Steven Rostedt
2014-03-25 10:24 ` Masami Hiramatsu
2014-03-25 10:58 ` Steven Rostedt
2014-03-05 12:00 ` [PATCH -tip v8 14/26] x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation Masami Hiramatsu
2014-03-24 19:45 ` Steven Rostedt
2014-03-25 10:33 ` Masami Hiramatsu
2014-03-05 12:00 ` [PATCH -tip v8 13/26] x86: Allow kprobes on text_poke/hw_breakpoint Masami Hiramatsu
2014-03-24 19:40 ` Steven Rostedt
2014-03-05 12:00 ` [PATCH -tip v8 18/26] sched: Use NOKPROBE_SYMBOL macro in sched Masami Hiramatsu
2014-03-24 20:14 ` Steven Rostedt
2014-03-05 12:00 ` [PATCH -tip v8 12/26] ftrace/*probes: Allow probing on some functions Masami Hiramatsu
2014-03-24 19:38 ` Steven Rostedt
2014-03-25 9:30 ` Masami Hiramatsu
2014-03-05 12:00 ` [PATCH -tip v8 11/26] kprobes: Allow probe on some kprobe functions Masami Hiramatsu
2014-03-24 19:37 ` Steven Rostedt
2014-03-25 9:23 ` Masami Hiramatsu
2014-03-05 12:01 ` Masami Hiramatsu [this message]
2014-03-05 12:01 ` [PATCH -tip v8 19/26] kprobes: Show blacklist entries via debugfs Masami Hiramatsu
2014-03-24 20:19 ` Steven Rostedt
2014-03-25 10:30 ` Masami Hiramatsu
2014-03-05 12:01 ` [PATCH -tip v8 21/26] kprobes: Use NOKPROBE_SYMBOL() in sample modules Masami Hiramatsu
2014-03-05 12:01 ` [PATCH -tip v8 20/26] kprobes: Support blacklist functions in module Masami Hiramatsu
2014-03-05 12:01 ` [PATCH -tip v8 24/26] kprobes: Enlarge hash table to 512 entries Masami Hiramatsu
2014-03-05 12:01 ` [PATCH -tip v8 25/26] kprobes: Introduce kprobe cache to reduce cache misshits Masami Hiramatsu
2014-03-05 12:01 ` [PATCH -tip v8 26/26] ftrace: Introduce FTRACE_OPS_FL_SELF_FILTER for ftrace-kprobe Masami Hiramatsu
2014-03-05 12:01 ` [PATCH -tip v8 22/26] kprobes/x86: Use kprobe_blacklist for .kprobes.text and .entry.text Masami Hiramatsu
2014-03-14 13:11 ` [PATCH -tip v8 00/26] kprobes: introduce NOKPROBE_SYMBOL, bugfixes and scalbility efforts Masami Hiramatsu
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