From: Sudeep Holla <sudeep.holla@arm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Haibo Xu <haibo.xu@arm.com>, Steve Capper <Steve.Capper@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
jdike@addtoit.com, x86@kernel.org,
Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, Bin Lu <bin.lu@arm.com>,
Richard Weinberger <richard@nod.at>,
Ingo Molnar <mingo@redhat.com>, Paul Mackerras <paulus@samba.org>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 3/6] x86: clean up _TIF_SYSCALL_EMU handling using ptrace_syscall_enter hook
Date: Wed, 1 May 2019 17:51:51 +0100 [thread overview]
Message-ID: <20190501165151.GB12498@e107155-lin> (raw)
In-Reply-To: <20190501155711.GB30235@redhat.com>
On Wed, May 01, 2019 at 05:57:11PM +0200, Oleg Nesterov wrote:
> On 04/30, Sudeep Holla wrote:
> >
> > On Mon, Mar 18, 2019 at 04:33:22PM +0100, Oleg Nesterov wrote:
> > >
> > > And it seems that _TIF_WORK_SYSCALL_ENTRY needs some cleanups too... We don't need
> > > "& _TIF_WORK_SYSCALL_ENTRY" in syscall_trace_enter, and _TIF_WORK_SYSCALL_ENTRY
> > > should not include _TIF_NOHZ?
> > >
> >
> > I was about to post the updated version and checked this to make sure I have
> > covered everything or not. I had missed the above comment. All architectures
> > have _TIF_NOHZ in their mask that they check to do work. And from x86, I read
> > "...syscall_trace_enter(). Also includes TIF_NOHZ for enter_from_user_mode()"
> > So I don't understand why _TIF_NOHZ needs to be dropped.
>
> I have already forgot this discussion... But after I glanced at this code again
> I still think the same, and I don't understand why do you disagree.
>
Sorry, but I didn't have any disagreement, I just said I don't understand
the usage on all architectures at that moment.
> > Also if we need to drop, we can address that separately examining all archs.
>
> Sure, and I was only talking about x86. We can keep TIF_NOHZ and even
> set_tsk_thread_flag(TIF_NOHZ) in context_tracking_cpu_set() if some arch needs
> this but remove TIF_NOHZ from TIF_WORK_SYSCALL_ENTRY in arch/x86/include/asm/thread_info.h,
> afaics this shouldn't make any difference.
>
OK, it's just x86, then I understand your point. I was looking at all
the architectures, sorry for the confusion.
> And I see no reason why x86 needs to use TIF_WORK_SYSCALL_ENTRY in
> syscall_trace_enter().
>
Agreed
--
Regards,
Sudeep
next prev parent reply other threads:[~2019-05-01 16:53 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 10:49 [PATCH v2 0/6] ptrace: consolidate PTRACE_SYSEMU handling and add support for arm64 Sudeep Holla
2019-03-18 10:49 ` [PATCH v2 1/6] ptrace: move clearing of TIF_SYSCALL_EMU flag to core Sudeep Holla
2019-03-18 17:29 ` Oleg Nesterov
2019-03-18 10:49 ` [PATCH v2 2/6] ptrace: introduce ptrace_syscall_enter to consolidate PTRACE_SYSEMU handling Sudeep Holla
2019-03-18 14:31 ` Dmitry V. Levin
2019-03-18 14:55 ` Sudeep Holla
2019-03-18 14:41 ` Dmitry V. Levin
2019-03-18 14:57 ` Sudeep Holla
2019-03-18 10:49 ` [PATCH v2 3/6] x86: clean up _TIF_SYSCALL_EMU handling using ptrace_syscall_enter hook Sudeep Holla
2019-03-18 15:33 ` Oleg Nesterov
2019-04-30 16:44 ` Sudeep Holla
2019-05-01 15:57 ` Oleg Nesterov
2019-05-01 16:51 ` Sudeep Holla [this message]
2019-04-30 16:46 ` Andy Lutomirski
2019-04-30 17:09 ` Sudeep Holla
2019-03-18 10:49 ` [PATCH v2 4/6] powerpc: use common ptrace_syscall_enter hook to handle _TIF_SYSCALL_EMU Sudeep Holla
2019-03-18 14:26 ` Dmitry V. Levin
2019-03-18 14:59 ` Sudeep Holla
2019-03-18 17:20 ` Oleg Nesterov
2019-03-18 17:24 ` Sudeep Holla
2019-03-18 17:33 ` Oleg Nesterov
2019-03-18 17:40 ` Sudeep Holla
2019-03-19 17:08 ` Oleg Nesterov
2019-03-19 17:32 ` Oleg Nesterov
2019-04-03 16:50 ` Will Deacon
2019-03-18 10:49 ` [PATCH v2 5/6] arm64: add PTRACE_SYSEMU{, SINGLESTEP} definations to uapi headers Sudeep Holla
2019-03-18 10:49 ` [PATCH v2 6/6] arm64: ptrace: add support for syscall emulation Sudeep Holla
2019-03-19 3:26 ` Haibo Xu (Arm Technology China)
2019-03-18 20:04 ` [PATCH v2 0/6] ptrace: consolidate PTRACE_SYSEMU handling and add support for arm64 Andy Lutomirski
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