From: masami.hiramatsu.pt@hitachi•com (Masami Hiramatsu)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC PATCH] kprobes: arm: enable OPTPROBES for arm 32
Date: Thu, 07 Aug 2014 15:59:29 +0900 [thread overview]
Message-ID: <53E323D1.8020209@hitachi.com> (raw)
In-Reply-To: <53E1CA11.1030206@huawei.com>
(2014/08/06 15:24), Wang Nan wrote:
>>> +
>>> +static void
>>> +optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
>>> +{
>>> + unsigned long flags;
>>> +
>>> + regs->ARM_pc = (unsigned long)op->kp.addr;
>>> + regs->ARM_ORIG_r0 = ~0UL;
>>> +
>>> +
>>> + local_irq_save(flags);
>>> + /*
>>> + * This is possible if op is under delayed unoptimizing.
>>> + * We need simulate the replaced instruction.
>>> + */
>>> + if (kprobe_disabled(&op->kp)) {
>>> + struct kprobe *p = &op->kp;
>>> + op->kp.ainsn.insn_singlestep(p->opcode, &p->ainsn, regs);
>>> + } else {
>>> + kprobe_handler(regs);
>>> + }
>>
>> You don't need brace "{}" for one statement.
>> By the way, why don't you call opt_pre_handler()?
>>
>
> I use kprobe_handler because it handles instruction emulation.
>
> In addition, I'm not very sure whether skipping the complex checks
> in kprobe_handler() is safe or not.
That seems to do same thing on x86. Then you should do something like
the optimized_callback() on x86 as below.
static void
optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
unsigned long flags;
local_irq_save(flags);
if (kprobe_running()) {
kprobes_inc_nmissed_count(&op->kp);
} else {
/* Save skipped registers */
regs->ARM_pc = (unsigned long)op->kp.addr;
regs->ARM_ORIG_r0 = ~0UL;
__this_cpu_write(current_kprobe, &op->kp);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
opt_pre_handler(&op->kp, regs);
__this_cpu_write(current_kprobe, NULL);
op->kp.ainsn.insn_singlestep(op->kp.opcode, &op->kp.ainsn, regs);
}
local_irq_restore(flags);
}
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt at hitachi.com
next prev parent reply other threads:[~2014-08-07 6:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-05 7:28 [RFC PATCH] kprobes: arm: enable OPTPROBES for arm 32 Wang Nan
2014-08-06 4:44 ` Masami Hiramatsu
2014-08-06 6:24 ` Wang Nan
2014-08-07 6:59 ` Masami Hiramatsu [this message]
2014-08-08 1:25 ` Wang Nan
2014-08-08 2:07 ` Masami Hiramatsu
2014-08-06 13:36 ` Jon Medhurst (Tixy)
2014-08-06 13:40 ` Wang Nan
2014-08-06 14:23 ` Jon Medhurst (Tixy)
2014-08-06 22:57 ` Russell King - ARM Linux
2014-08-06 22:55 ` Russell King - ARM Linux
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