From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Ingo Molnar <mingo@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [PATCH v3 6/7] powerpc: kprobes: emulate instructions on kprobe handler re-entry
Date: Wed, 19 Apr 2017 16:42:50 +0000 [thread overview]
Message-ID: <1492620027.h27iuc5j5o.astroid@naverao1-tp.none> (raw)
In-Reply-To: <20170419234319.7893df9c158e565fede4a386@kernel.org>
Excerpts from Masami Hiramatsu's message of April 19, 2017 20:13:
>
> BTW, as I pointed, 5/7 and 6/7 should be merged since this actually
> makes meaningful change.
Yes, sorry if I wasn't clear in my previous reply in the (!) previous
patch series.
Since this has to go through the powerpc tree, I followed this since I
felt that Michael Ellerman prefers to keep functional changes separate
from refactoring. I'm fine with either approach.
Michael?
Thanks!
- Naveen
>
> Thank you,
>
> On Wed, 19 Apr 2017 18:21:05 +0530
> "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
>
>> On kprobe handler re-entry, try to emulate the instruction rather than
>> single stepping always.
>>
>> Acked-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
>> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
>> ---
>> arch/powerpc/kernel/kprobes.c | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>>
>> diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
>> index 46e8c1e03ce4..067e9863bfdf 100644
>> --- a/arch/powerpc/kernel/kprobes.c
>> +++ b/arch/powerpc/kernel/kprobes.c
>> @@ -276,6 +276,14 @@ int __kprobes kprobe_handler(struct pt_regs *regs)
>> kprobes_inc_nmissed_count(p);
>> prepare_singlestep(p, regs);
>> kcb->kprobe_status = KPROBE_REENTER;
>> + if (p->ainsn.boostable >= 0) {
>> + ret = try_to_emulate(p, regs);
>> +
>> + if (ret > 0) {
>> + restore_previous_kprobe(kcb);
>> + return 1;
>> + }
>> + }
>> return 1;
>> } else {
>> if (*addr != BREAKPOINT_INSTRUCTION) {
>> --
>> 2.12.1
>>
>
>
> --
> Masami Hiramatsu <mhiramat@kernel.org>
>
>
next prev parent reply other threads:[~2017-04-19 16:44 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 12:50 [PATCH v3 0/7] powerpc: a few kprobe fixes and refactoring Naveen N. Rao
2017-04-19 12:51 ` [PATCH v3 1/7] kprobes: convert kprobe_lookup_name() to a function Naveen N. Rao
2017-04-24 22:47 ` [v3,1/7] " Michael Ellerman
2017-04-19 12:51 ` [PATCH v3 2/7] powerpc: kprobes: fix handling of function offsets on ABIv2 Naveen N. Rao
2017-04-24 22:47 ` [v3,2/7] " Michael Ellerman
2017-04-19 12:51 ` [PATCH v3 3/7] kprobes: validate the symbol name length Naveen N. Rao
2017-04-19 14:37 ` Masami Hiramatsu
2017-04-19 16:38 ` Naveen N. Rao
2017-04-21 13:42 ` Masami Hiramatsu
2017-04-23 15:44 ` Naveen N. Rao
2017-04-25 3:18 ` Masami Hiramatsu
2017-04-20 6:08 ` Michael Ellerman
2017-04-20 7:19 ` Naveen N. Rao
2017-04-21 12:32 ` [PATCH v4 3/7] kprobes: validate the symbol name provided during probe registration Naveen N. Rao
2017-04-21 13:11 ` Paul Clarke
2017-04-21 13:25 ` Naveen N. Rao
2017-04-21 13:54 ` Masami Hiramatsu
2017-04-22 5:55 ` Michael Ellerman
2017-04-23 17:41 ` Naveen N. Rao
2017-04-21 12:33 ` [PATCH v4 4/7] powerpc/kprobes: Use safer string functions in kprobe_lookup_name() Naveen N. Rao
2017-04-21 13:33 ` Paul Clarke
2017-04-21 13:36 ` Paul Clarke
2017-04-21 13:52 ` Paul Clarke
2017-04-23 17:09 ` Naveen N. Rao
2017-04-19 12:51 ` [PATCH v3 4/7] powerpc: kprobes: use " Naveen N. Rao
2017-04-21 15:06 ` David Laight
2017-04-19 12:51 ` [PATCH v3 5/7] powerpc: kprobes: factor out code to emulate instruction into a helper Naveen N. Rao
2017-04-19 14:40 ` Masami Hiramatsu
2017-04-24 22:47 ` [v3, " Michael Ellerman
2017-04-19 12:51 ` [PATCH v3 6/7] powerpc: kprobes: emulate instructions on kprobe handler re-entry Naveen N. Rao
2017-04-19 14:43 ` Masami Hiramatsu
2017-04-19 16:42 ` Naveen N. Rao [this message]
2017-04-20 6:11 ` Michael Ellerman
2017-04-21 13:48 ` Masami Hiramatsu
2017-04-24 22:47 ` [v3, " Michael Ellerman
2017-04-19 12:51 ` [PATCH v3 7/7] powerpc: kprobes: remove duplicate saving of msr Naveen N. Rao
2017-04-19 14:43 ` Masami Hiramatsu
2017-04-23 11:53 ` [v3,7/7] " Michael Ellerman
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