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From: Leo Yan <leo.yan@linaro.org>
To: James Clark <james.clark@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Kees Cook <keescook@chromium.org>,
	Ard Biesheuvel <ardb@kernel.org>,
	Sami Tolvanen <samitolvanen@google.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	James Morse <james.morse@arm.com>, Marc Zyngier <maz@kernel.org>,
	Joey Gouly <joey.gouly@arm.com>,
	Peter Collingbourne <pcc@google.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Stephane Eranian <eranian@google.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFCv1 1/4] arm64: Use static key for tracing PID in CONTEXTIDR
Date: Thu, 21 Oct 2021 22:37:26 +0800	[thread overview]
Message-ID: <20211021143726.GA213960@leoy-ThinkPad-X240s> (raw)
In-Reply-To: <53962765-53b9-dfdc-a5b2-a3133a924c12@arm.com>

Hi James,

On Thu, Oct 21, 2021 at 03:33:01PM +0100, James Clark wrote:

[...]

> > +static int __init contextidr_init(void)
> > +{
> > +	if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR))
> > +		static_branch_inc(&contextidr_in_use);
> > +	return 0;
> > +}
> > +early_initcall(contextidr_init);
> 
> Hi Leo,
> 
> Can you skip this early_initcall() part if you do something like this:
> 
>     DECLARE_STATIC_KEY_MAYBE(CONFIG_PID_IN_CONTEXTIDR, contextidr_in_use)
> 
> It seems like there is a way to conditionally initialise it to true.

Thanks for good point!  Will test this way in next spin.

Leo

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WARNING: multiple messages have this Message-ID (diff)
From: Leo Yan <leo.yan@linaro.org>
To: James Clark <james.clark@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Kees Cook <keescook@chromium.org>,
	Ard Biesheuvel <ardb@kernel.org>,
	Sami Tolvanen <samitolvanen@google.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	James Morse <james.morse@arm.com>, Marc Zyngier <maz@kernel.org>,
	Joey Gouly <joey.gouly@arm.com>,
	Peter Collingbourne <pcc@google.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Stephane Eranian <eranian@google.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFCv1 1/4] arm64: Use static key for tracing PID in CONTEXTIDR
Date: Thu, 21 Oct 2021 22:37:26 +0800	[thread overview]
Message-ID: <20211021143726.GA213960@leoy-ThinkPad-X240s> (raw)
In-Reply-To: <53962765-53b9-dfdc-a5b2-a3133a924c12@arm.com>

Hi James,

On Thu, Oct 21, 2021 at 03:33:01PM +0100, James Clark wrote:

[...]

> > +static int __init contextidr_init(void)
> > +{
> > +	if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR))
> > +		static_branch_inc(&contextidr_in_use);
> > +	return 0;
> > +}
> > +early_initcall(contextidr_init);
> 
> Hi Leo,
> 
> Can you skip this early_initcall() part if you do something like this:
> 
>     DECLARE_STATIC_KEY_MAYBE(CONFIG_PID_IN_CONTEXTIDR, contextidr_in_use)
> 
> It seems like there is a way to conditionally initialise it to true.

Thanks for good point!  Will test this way in next spin.

Leo

  reply	other threads:[~2021-10-21 14:38 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-21 13:45 [RFCv1 0/4] arm64: Use static key for PID in CONTEXTIDR Leo Yan
2021-10-21 13:45 ` Leo Yan
2021-10-21 13:45 ` [RFCv1 1/4] arm64: Use static key for tracing " Leo Yan
2021-10-21 13:45   ` Leo Yan
2021-10-21 14:33   ` James Clark
2021-10-21 14:33     ` James Clark
2021-10-21 14:37     ` Leo Yan [this message]
2021-10-21 14:37       ` Leo Yan
2021-10-21 15:47     ` Kees Cook
2021-10-21 15:47       ` Kees Cook
2021-10-21 13:45 ` [RFCv1 2/4] arm64: entry: Always apply workaround for contextidr_el1 Leo Yan
2021-10-21 13:45   ` Leo Yan
2021-10-21 13:45 ` [RFCv1 3/4] arm64: Introduce functions for controlling PID tracing Leo Yan
2021-10-21 13:45   ` Leo Yan
2021-10-21 13:45 ` [RFCv1 4/4] perf: arm_spe: Dynamically switch PID tracing to contextidr Leo Yan
2021-10-21 13:45   ` Leo Yan
2021-10-21 15:49   ` Kees Cook
2021-10-21 15:49     ` Kees Cook
2021-10-22  2:09     ` Leo Yan
2021-10-22  2:09       ` Leo Yan
2021-11-01 15:28     ` Leo Yan
2021-11-01 15:28       ` Leo Yan
2021-12-03 16:22       ` Catalin Marinas
2021-12-03 16:22         ` Catalin Marinas
2021-12-05 13:51         ` Leo Yan
2021-12-05 13:51           ` Leo Yan
2021-12-07 11:48           ` Catalin Marinas
2021-12-07 11:48             ` Catalin Marinas
2021-12-07 12:31             ` Leo Yan
2021-12-07 12:31               ` Leo Yan
2021-12-08 17:29               ` Catalin Marinas
2021-12-08 17:29                 ` Catalin Marinas
2021-12-10  7:59                 ` Leo Yan
2021-12-10  7:59                   ` Leo Yan
2021-12-17  7:58                   ` Leo Yan
2021-12-17  7:58                     ` Leo Yan
2022-01-17 18:48                   ` Catalin Marinas
2022-01-17 18:48                     ` Catalin Marinas
2022-02-01 13:02                     ` Leo Yan
2022-02-01 13:02                       ` Leo Yan
2021-10-22 15:36   ` James Clark
2021-10-22 15:36     ` James Clark
2021-10-22 15:40     ` James Clark
2021-10-22 15:40       ` James Clark
2021-10-22 16:23     ` James Clark
2021-10-22 16:23       ` James Clark
2021-10-24 10:25       ` Leo Yan
2021-10-24 10:25         ` Leo Yan

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