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From: Ard Biesheuvel <ardb@kernel.org>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	linux-rt-users@vger.kernel.org, X86 ML <x86@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Steven Rostedt <rostedt@goodmis.org>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>, Mark Brown <broonie@kernel.org>,
	Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH 0/3] sched, x86, arm64: PREEMPT_RT, FPU and preemption
Date: Fri, 23 Jul 2021 16:12:49 +0200	[thread overview]
Message-ID: <CAMj1kXE8Yyn0orHe3DjFvCQ3k5mUKJF10BcJ3fJTessRoMShBA@mail.gmail.com> (raw)
In-Reply-To: <20210722175157.1367122-1-valentin.schneider@arm.com>

On Thu, 22 Jul 2021 at 19:53, Valentin Schneider
<valentin.schneider@arm.com> wrote:
>
> Hi folks,
>
> This stems from some more v5.13-rt1 breakage on arm64. This time per-CPU access
> safety isn't sufficient, we really need to keep preemption disabled.
>
> In a happy accident I stumbled on
>
>   cba08c5dc6dc ("x86/fpu: Make kernel FPU protection RT friendly")
>
> so I packaged what was done there into some common helpers and plastered them
> over the problematic areas.
>
> Cheers,
> Valentin
>
> Valentin Schneider (3):
>   sched/preempt: Introduce preempt_{enable, disable}_bh()
>   x86/fpu: Make FPU protection reuse common helper
>   arm64/fpsimd: Fix FPSIMD context handling vs PREEMPT_RT
>

Thanks for fixing this.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>


>  arch/arm64/kernel/fpsimd.c     |  6 ++++--
>  arch/x86/include/asm/fpu/api.h | 19 ++-----------------
>  include/linux/bottom_half.h    | 26 ++++++++++++++++++++++++++
>  3 files changed, 32 insertions(+), 19 deletions(-)
>
> --
> 2.25.1
>

WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ardb@kernel.org>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	 Linux ARM <linux-arm-kernel@lists.infradead.org>,
	linux-rt-users@vger.kernel.org,  X86 ML <x86@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	 Thomas Gleixner <tglx@linutronix.de>,
	Steven Rostedt <rostedt@goodmis.org>,
	 Daniel Bristot de Oliveira <bristot@redhat.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	 Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	 Mark Brown <broonie@kernel.org>,
	Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH 0/3] sched, x86, arm64: PREEMPT_RT, FPU and preemption
Date: Fri, 23 Jul 2021 16:12:49 +0200	[thread overview]
Message-ID: <CAMj1kXE8Yyn0orHe3DjFvCQ3k5mUKJF10BcJ3fJTessRoMShBA@mail.gmail.com> (raw)
In-Reply-To: <20210722175157.1367122-1-valentin.schneider@arm.com>

On Thu, 22 Jul 2021 at 19:53, Valentin Schneider
<valentin.schneider@arm.com> wrote:
>
> Hi folks,
>
> This stems from some more v5.13-rt1 breakage on arm64. This time per-CPU access
> safety isn't sufficient, we really need to keep preemption disabled.
>
> In a happy accident I stumbled on
>
>   cba08c5dc6dc ("x86/fpu: Make kernel FPU protection RT friendly")
>
> so I packaged what was done there into some common helpers and plastered them
> over the problematic areas.
>
> Cheers,
> Valentin
>
> Valentin Schneider (3):
>   sched/preempt: Introduce preempt_{enable, disable}_bh()
>   x86/fpu: Make FPU protection reuse common helper
>   arm64/fpsimd: Fix FPSIMD context handling vs PREEMPT_RT
>

Thanks for fixing this.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>


>  arch/arm64/kernel/fpsimd.c     |  6 ++++--
>  arch/x86/include/asm/fpu/api.h | 19 ++-----------------
>  include/linux/bottom_half.h    | 26 ++++++++++++++++++++++++++
>  3 files changed, 32 insertions(+), 19 deletions(-)
>
> --
> 2.25.1
>

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

  parent reply	other threads:[~2021-07-23 14:13 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-22 17:51 [PATCH 0/3] sched, x86, arm64: PREEMPT_RT, FPU and preemption Valentin Schneider
2021-07-22 17:51 ` Valentin Schneider
2021-07-22 17:51 ` [PATCH 1/3] sched/preempt: Introduce preempt_{enable, disable}_bh() Valentin Schneider
2021-07-22 17:51   ` Valentin Schneider
2021-07-22 17:51 ` [PATCH 2/3] x86/fpu: Make FPU protection reuse common helper Valentin Schneider
2021-07-22 17:51   ` Valentin Schneider
2021-07-22 17:51 ` [PATCH 3/3] arm64/fpsimd: Fix FPSIMD context handling vs PREEMPT_RT Valentin Schneider
2021-07-22 17:51   ` Valentin Schneider
2021-07-22 18:32   ` Mark Brown
2021-07-22 18:32     ` Mark Brown
2021-07-23 11:07     ` Valentin Schneider
2021-07-23 11:07       ` Valentin Schneider
2021-07-22 20:11 ` [PATCH 0/3] sched, x86, arm64: PREEMPT_RT, FPU and preemption Andrew Halaney
2021-07-22 20:11   ` Andrew Halaney
2021-07-23 14:12 ` Ard Biesheuvel [this message]
2021-07-23 14:12   ` Ard Biesheuvel

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