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From: Oleg Nesterov <oleg@redhat.com>
To: Sudeep Holla <sudeep.holla@arm.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>,
	Thomas Gleixner <tglx@linutronix.de>,
	linuxppc-dev@lists.ozlabs.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 4/6] powerpc: use common ptrace_syscall_enter hook to handle _TIF_SYSCALL_EMU
Date: Mon, 18 Mar 2019 18:33:41 +0100	[thread overview]
Message-ID: <20190318173341.GD23521@redhat.com> (raw)
In-Reply-To: <20190318172457.GD18196@e107155-lin>

On 03/18, Sudeep Holla wrote:
>
> On Mon, Mar 18, 2019 at 06:20:24PM +0100, Oleg Nesterov wrote:
> >
> > Again, to me this patch just makes the code look worse. Honestly, I don't
> > think that the new (badly named) ptrace_syscall_enter() hook makes any sense.
> >
>
> Worse because we end up reading current_thread_info->flags twice ?

Mostly because in my opinion ptrace_syscall_enter() buys nothing but makes
the caller's code less readable/understandable.

Sure, this is subjective.

Oleg.


WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Sudeep Holla <sudeep.holla@arm.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>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Thomas Gleixner <tglx@linutronix.de>,
	linuxppc-dev@lists.ozlabs.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 4/6] powerpc: use common ptrace_syscall_enter hook to handle _TIF_SYSCALL_EMU
Date: Mon, 18 Mar 2019 18:33:41 +0100	[thread overview]
Message-ID: <20190318173341.GD23521@redhat.com> (raw)
In-Reply-To: <20190318172457.GD18196@e107155-lin>

On 03/18, Sudeep Holla wrote:
>
> On Mon, Mar 18, 2019 at 06:20:24PM +0100, Oleg Nesterov wrote:
> >
> > Again, to me this patch just makes the code look worse. Honestly, I don't
> > think that the new (badly named) ptrace_syscall_enter() hook makes any sense.
> >
>
> Worse because we end up reading current_thread_info->flags twice ?

Mostly because in my opinion ptrace_syscall_enter() buys nothing but makes
the caller's code less readable/understandable.

Sure, this is subjective.

Oleg.


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: x86@kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Richard Weinberger <richard@nod.at>,
	jdike@addtoit.com, Steve Capper <Steve.Capper@arm.com>,
	Haibo Xu <haibo.xu@arm.com>, Bin Lu <bin.lu@arm.com>,
	Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH v2 4/6] powerpc: use common ptrace_syscall_enter hook to handle _TIF_SYSCALL_EMU
Date: Mon, 18 Mar 2019 18:33:41 +0100	[thread overview]
Message-ID: <20190318173341.GD23521@redhat.com> (raw)
In-Reply-To: <20190318172457.GD18196@e107155-lin>

On 03/18, Sudeep Holla wrote:
>
> On Mon, Mar 18, 2019 at 06:20:24PM +0100, Oleg Nesterov wrote:
> >
> > Again, to me this patch just makes the code look worse. Honestly, I don't
> > think that the new (badly named) ptrace_syscall_enter() hook makes any sense.
> >
>
> Worse because we end up reading current_thread_info->flags twice ?

Mostly because in my opinion ptrace_syscall_enter() buys nothing but makes
the caller's code less readable/understandable.

Sure, this is subjective.

Oleg.


  reply	other threads:[~2019-03-18 17:36 UTC|newest]

Thread overview: 87+ 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 ` Sudeep Holla
2019-03-18 10:49 ` 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 10:49   ` Sudeep Holla
2019-03-18 10:49   ` Sudeep Holla
2019-03-18 17:29   ` Oleg Nesterov
2019-03-18 17:29     ` Oleg Nesterov
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 10:49   ` Sudeep Holla
2019-03-18 10:49   ` Sudeep Holla
2019-03-18 14:31   ` Dmitry V. Levin
2019-03-18 14:31     ` Dmitry V. Levin
2019-03-18 14:31     ` Dmitry V. Levin
2019-03-18 14:55     ` Sudeep Holla
2019-03-18 14:55       ` Sudeep Holla
2019-03-18 14:55       ` Sudeep Holla
2019-03-18 14:41   ` Dmitry V. Levin
2019-03-18 14:41     ` Dmitry V. Levin
2019-03-18 14:41     ` Dmitry V. Levin
2019-03-18 14:57     ` Sudeep Holla
2019-03-18 14:57       ` Sudeep Holla
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 10:49   ` Sudeep Holla
2019-03-18 10:49   ` Sudeep Holla
2019-03-18 15:33   ` Oleg Nesterov
2019-03-18 15:33     ` Oleg Nesterov
2019-03-18 15:33     ` Oleg Nesterov
2019-04-30 16:44     ` Sudeep Holla
2019-04-30 16:44       ` Sudeep Holla
2019-04-30 16:44       ` Sudeep Holla
2019-05-01 15:57       ` Oleg Nesterov
2019-05-01 15:57         ` Oleg Nesterov
2019-05-01 15:57         ` Oleg Nesterov
2019-05-01 16:51         ` Sudeep Holla
2019-05-01 16:51           ` Sudeep Holla
2019-05-01 16:51           ` Sudeep Holla
2019-04-30 16:46   ` Andy Lutomirski
2019-04-30 16:46     ` Andy Lutomirski
2019-04-30 16:46     ` Andy Lutomirski
2019-04-30 17:09     ` Sudeep Holla
2019-04-30 17:09       ` Sudeep Holla
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 10:49   ` Sudeep Holla
2019-03-18 10:49   ` Sudeep Holla
2019-03-18 14:26   ` Dmitry V. Levin
2019-03-18 14:26     ` Dmitry V. Levin
2019-03-18 14:26     ` Dmitry V. Levin
2019-03-18 14:59     ` Sudeep Holla
2019-03-18 14:59       ` Sudeep Holla
2019-03-18 14:59       ` Sudeep Holla
2019-03-18 17:20   ` Oleg Nesterov
2019-03-18 17:20     ` Oleg Nesterov
2019-03-18 17:20     ` Oleg Nesterov
2019-03-18 17:24     ` Sudeep Holla
2019-03-18 17:24       ` Sudeep Holla
2019-03-18 17:24       ` Sudeep Holla
2019-03-18 17:33       ` Oleg Nesterov [this message]
2019-03-18 17:33         ` Oleg Nesterov
2019-03-18 17:33         ` Oleg Nesterov
2019-03-18 17:40         ` Sudeep Holla
2019-03-18 17:40           ` Sudeep Holla
2019-03-18 17:40           ` Sudeep Holla
2019-03-19 17:08           ` Oleg Nesterov
2019-03-19 17:08             ` Oleg Nesterov
2019-03-19 17:08             ` Oleg Nesterov
2019-03-19 17:32             ` Oleg Nesterov
2019-03-19 17:32               ` Oleg Nesterov
2019-03-19 17:32               ` Oleg Nesterov
2019-04-03 16:50               ` Will Deacon
2019-04-03 16:50                 ` Will Deacon
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 5/6] arm64: add PTRACE_SYSEMU{,SINGLESTEP} " Sudeep Holla
2019-03-18 10:49   ` [PATCH v2 5/6] arm64: add PTRACE_SYSEMU{, SINGLESTEP} " Sudeep Holla
2019-03-18 10:49 ` [PATCH v2 6/6] arm64: ptrace: add support for syscall emulation Sudeep Holla
2019-03-18 10:49   ` Sudeep Holla
2019-03-18 10:49   ` Sudeep Holla
2019-03-19  3:26   ` Haibo Xu (Arm Technology China)
2019-03-19  3:26     ` Haibo Xu (Arm Technology China)
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
2019-03-18 20:04   ` Andy Lutomirski
2019-03-18 20:04   ` Andy Lutomirski

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