From: Arnd Bergmann <arnd@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: Hector Martin <marcan@marcan.st>, SoC Team <soc@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Rob Herring <robh+dt@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
DTML <devicetree@vger.kernel.org>,
Olof Johansson <olof@lixom.net>
Subject: Re: [PATCH 10/18] arm64: Introduce FIQ support
Date: Sat, 6 Feb 2021 17:22:26 +0100 [thread overview]
Message-ID: <CAK8P3a0-Qk1WAUaCWeX8Zypphpadan3YAOES9t7LFYBOJkXKog@mail.gmail.com> (raw)
In-Reply-To: <87h7mpky0f.wl-maz@kernel.org>
On Sat, Feb 6, 2021 at 4:37 PM Marc Zyngier <maz@kernel.org> wrote:
> On Thu, 04 Feb 2021 20:39:43 +0000, Hector Martin <marcan@marcan.st> wrote:
> > diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
> > index bf125c591116..6acfc372dc76 100644
> > --- a/arch/arm64/include/asm/assembler.h
> > +++ b/arch/arm64/include/asm/assembler.h
> > @@ -42,7 +42,11 @@
> >
> > /* IRQ is the lowest priority flag, unconditionally unmask the rest. */
> > .macro enable_da_f
> > +alternative_if ARM64_NEEDS_FIQ
> > + msr daifclr, #(8 | 4)
> > +alternative_else
> > msr daifclr, #(8 | 4 | 1)
> > +alternative_endif
>
> See my digression in patch 8. I really wonder what the benefit is to
> treat FIQ independently of IRQ, and we might as well generalise
> this. We could always panic on getting a FIQ on platforms that don't
> expect one.
>
> It'd be good to rope in the other interested parties (Mark for the
> early entry code, James for RAS and SError handling).
There might be another slightly hacky but less intrusive option
that could be done (almost) purely within the aic code:
* In the fiq handler code, check if normal interrupts were enabled
when the fiq hit. Normally they are enabled, so just proceed to
handle the timer and ipi directly
* if irq was disabled, defer the handling by doing a self-ipi
through the aic's ipi method, and handle it from there
when dealing with the next interrupt once interrupts get
enabled.
This would be similar to the soft-disable feature on powerpc, which
never actually turns off interrupts from regular kernel code but
just checks a flag in local_irq_enable that gets set when a
hardirq happened.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: DTML <devicetree@vger.kernel.org>,
Hector Martin <marcan@marcan.st>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
SoC Team <soc@kernel.org>, Rob Herring <robh+dt@kernel.org>,
Olof Johansson <olof@lixom.net>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 10/18] arm64: Introduce FIQ support
Date: Sat, 6 Feb 2021 17:22:26 +0100 [thread overview]
Message-ID: <CAK8P3a0-Qk1WAUaCWeX8Zypphpadan3YAOES9t7LFYBOJkXKog@mail.gmail.com> (raw)
Message-ID: <20210206162226.wQinUkqNyNX944GzHRW6su05AR8mb1VMAv--AXQuET4@z> (raw)
In-Reply-To: <87h7mpky0f.wl-maz@kernel.org>
On Sat, Feb 6, 2021 at 4:37 PM Marc Zyngier <maz@kernel.org> wrote:
> On Thu, 04 Feb 2021 20:39:43 +0000, Hector Martin <marcan@marcan.st> wrote:
> > diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
> > index bf125c591116..6acfc372dc76 100644
> > --- a/arch/arm64/include/asm/assembler.h
> > +++ b/arch/arm64/include/asm/assembler.h
> > @@ -42,7 +42,11 @@
> >
> > /* IRQ is the lowest priority flag, unconditionally unmask the rest. */
> > .macro enable_da_f
> > +alternative_if ARM64_NEEDS_FIQ
> > + msr daifclr, #(8 | 4)
> > +alternative_else
> > msr daifclr, #(8 | 4 | 1)
> > +alternative_endif
>
> See my digression in patch 8. I really wonder what the benefit is to
> treat FIQ independently of IRQ, and we might as well generalise
> this. We could always panic on getting a FIQ on platforms that don't
> expect one.
>
> It'd be good to rope in the other interested parties (Mark for the
> early entry code, James for RAS and SError handling).
There might be another slightly hacky but less intrusive option
that could be done (almost) purely within the aic code:
* In the fiq handler code, check if normal interrupts were enabled
when the fiq hit. Normally they are enabled, so just proceed to
handle the timer and ipi directly
* if irq was disabled, defer the handling by doing a self-ipi
through the aic's ipi method, and handle it from there
when dealing with the next interrupt once interrupts get
enabled.
This would be similar to the soft-disable feature on powerpc, which
never actually turns off interrupts from regular kernel code but
just checks a flag in local_irq_enable that gets set when a
hardirq happened.
Arnd
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-02-06 16:22 UTC|newest]
Thread overview: 240+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 20:39 [PATCH 00/18] Apple M1 SoC platform bring-up Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 20:39 ` [PATCH 01/18] dt-bindings: vendor-prefixes: add AAPL prefix Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-08 10:27 ` Krzysztof Kozlowski
2021-02-08 10:27 ` Krzysztof Kozlowski
2021-02-08 17:32 ` Rob Herring
2021-02-08 17:32 ` Rob Herring
2021-02-08 18:12 ` Krzysztof Kozlowski
2021-02-08 18:12 ` Krzysztof Kozlowski
2021-02-08 19:59 ` Arnd Bergmann
2021-02-08 19:59 ` Arnd Bergmann
2021-02-08 23:17 ` Hector Martin
2021-02-08 23:17 ` Hector Martin
2021-02-04 20:39 ` [PATCH 02/18] dt-bindings: arm: cpus: Add AAPL,firestorm & icestorm compatibles Hector Martin
2021-02-04 20:39 ` [PATCH 02/18] dt-bindings: arm: cpus: Add AAPL, firestorm " Hector Martin
2021-02-04 20:39 ` [PATCH 03/18] dt-bindings: arm: AAPL: Add bindings for Apple ARM platforms Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 20:39 ` [PATCH 04/18] arm64: Kconfig: Introduce CONFIG_ARCH_APPLE Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-06 13:17 ` Marc Zyngier
2021-02-06 13:17 ` Marc Zyngier
2021-02-07 8:05 ` Hector Martin 'marcan'
2021-02-07 8:05 ` Hector Martin 'marcan'
2021-02-04 20:39 ` [PATCH 05/18] tty: serial: samsung_tty: add support for Apple UARTs Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 23:55 ` kernel test robot
2021-02-04 23:55 ` kernel test robot
2021-02-04 23:55 ` kernel test robot
2021-02-05 9:44 ` Hector Martin 'marcan'
2021-02-05 9:44 ` Hector Martin 'marcan'
2021-02-05 2:19 ` kernel test robot
2021-02-05 2:19 ` kernel test robot
2021-02-05 2:19 ` kernel test robot
2021-02-06 13:15 ` Marc Zyngier
2021-02-06 13:15 ` Marc Zyngier
2021-02-07 9:12 ` Hector Martin 'marcan'
2021-02-07 9:12 ` Hector Martin 'marcan'
2021-02-07 9:26 ` Hector Martin 'marcan'
2021-02-07 9:26 ` Hector Martin 'marcan'
2021-02-08 9:36 ` Krzysztof Kozlowski
2021-02-08 9:36 ` Krzysztof Kozlowski
2021-02-08 16:14 ` Hector Martin
2021-02-08 16:14 ` Hector Martin
2021-02-08 10:34 ` Marc Zyngier
2021-02-08 10:34 ` Marc Zyngier
2021-02-08 16:18 ` Hector Martin
2021-02-08 16:18 ` Hector Martin
2021-02-08 16:46 ` Greg Kroah-Hartman
2021-02-08 16:46 ` Greg Kroah-Hartman
2021-02-08 23:22 ` Hector Martin
2021-02-08 23:22 ` Hector Martin
2021-02-08 10:54 ` Krzysztof Kozlowski
2021-02-08 10:54 ` Krzysztof Kozlowski
2021-02-08 16:10 ` Hector Martin
2021-02-08 16:10 ` Hector Martin
2021-02-08 18:37 ` Krzysztof Kozlowski
2021-02-08 18:37 ` Krzysztof Kozlowski
2021-02-08 23:23 ` Hector Martin
2021-02-08 23:23 ` Hector Martin
2021-02-04 20:39 ` [PATCH 06/18] dt-bindings: serial: samsung: Add AAPL,s5l-uart compatible Hector Martin
2021-02-04 20:39 ` [PATCH 06/18] dt-bindings: serial: samsung: Add AAPL, s5l-uart compatible Hector Martin
2021-02-04 20:39 ` [PATCH 07/18] tty: serial: samsung_tty: enable for ARCH_APPLE Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 21:16 ` Arnd Bergmann
2021-02-04 21:16 ` Arnd Bergmann
2021-02-04 21:27 ` Hector Martin 'marcan'
2021-02-04 21:27 ` Hector Martin 'marcan'
2021-02-04 20:39 ` [PATCH 08/18] arm64: cpufeature: Add a feature for FIQ support Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-06 13:58 ` Marc Zyngier
2021-02-06 13:58 ` Marc Zyngier
2021-02-07 8:28 ` Hector Martin 'marcan'
2021-02-07 8:28 ` Hector Martin 'marcan'
2021-02-08 11:29 ` Marc Zyngier
2021-02-08 11:29 ` Marc Zyngier
2021-02-08 15:51 ` Hector Martin
2021-02-08 15:51 ` Hector Martin
2021-02-04 20:39 ` [PATCH 09/18] arm64: cputype: Add CPU types for the Apple M1 big/little cores Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 20:39 ` [PATCH 10/18] arm64: Introduce FIQ support Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-06 15:37 ` Marc Zyngier
2021-02-06 15:37 ` Marc Zyngier
2021-02-06 16:22 ` Arnd Bergmann [this message]
2021-02-06 16:22 ` Arnd Bergmann
2021-02-07 8:36 ` Hector Martin 'marcan'
2021-02-07 8:36 ` Hector Martin 'marcan'
2021-02-07 12:25 ` Arnd Bergmann
2021-02-07 12:25 ` Arnd Bergmann
2021-02-07 15:38 ` Hector Martin 'marcan'
2021-02-07 15:38 ` Hector Martin 'marcan'
2021-02-07 18:49 ` Arnd Bergmann
2021-02-07 18:49 ` Arnd Bergmann
2021-02-08 23:34 ` Hector Martin
2021-02-08 23:34 ` Hector Martin
2021-02-07 8:47 ` Hector Martin 'marcan'
2021-02-07 8:47 ` Hector Martin 'marcan'
2021-02-08 11:30 ` Marc Zyngier
2021-02-08 11:30 ` Marc Zyngier
2021-02-04 20:39 ` [PATCH 11/18] arm64: Kconfig: Require FIQ support for ARCH_APPLE Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-06 15:46 ` Marc Zyngier
2021-02-06 15:46 ` Marc Zyngier
2021-02-07 9:23 ` Hector Martin 'marcan'
2021-02-07 9:23 ` Hector Martin 'marcan'
2021-02-08 12:05 ` Marc Zyngier
2021-02-08 12:05 ` Marc Zyngier
2021-02-08 15:48 ` Hector Martin
2021-02-08 15:48 ` Hector Martin
2021-02-04 20:39 ` [PATCH 12/18] arm64: setup: Use nGnRnE IO mappings for fixmap on Apple platforms Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 22:25 ` Arnd Bergmann
2021-02-04 22:25 ` Arnd Bergmann
2021-02-04 20:39 ` [PATCH 13/18] arm64: ioremap: use nGnRnE mappings on platforms that require it Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 22:21 ` Arnd Bergmann
2021-02-04 22:21 ` Arnd Bergmann
2021-02-08 22:57 ` Arnd Bergmann
2021-02-08 22:57 ` Arnd Bergmann
2021-02-08 23:20 ` Mark Kettenis
2021-02-08 23:20 ` Mark Kettenis
2021-02-09 0:25 ` Hector Martin
2021-02-09 0:25 ` Hector Martin
2021-02-09 9:15 ` Arnd Bergmann
2021-02-09 9:15 ` Arnd Bergmann
2021-02-09 9:58 ` Mark Kettenis
2021-02-09 9:58 ` Mark Kettenis
2021-02-09 11:22 ` Hector Martin
2021-02-09 11:22 ` Hector Martin
2021-02-09 9:35 ` Arnd Bergmann
2021-02-09 9:35 ` Arnd Bergmann
2021-02-10 12:24 ` Hector Martin
2021-02-10 12:24 ` Hector Martin
2021-02-10 13:40 ` Mark Kettenis
2021-02-10 13:40 ` Mark Kettenis
2021-02-04 20:39 ` [PATCH 14/18] dt-bindings: interrupt-controller: Add DT bindings for apple-aic Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-09 23:07 ` Rob Herring
2021-02-09 23:07 ` Rob Herring
2021-02-04 20:39 ` [PATCH 15/18] irqchip/apple-aic: Add support for the Apple Interrupt Controller Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 21:37 ` Arnd Bergmann
2021-02-04 21:37 ` Arnd Bergmann
2021-02-04 22:04 ` Hector Martin 'marcan'
2021-02-04 22:04 ` Hector Martin 'marcan'
2021-02-04 23:04 ` Arnd Bergmann
2021-02-04 23:04 ` Arnd Bergmann
2021-02-05 7:41 ` Hector Martin 'marcan'
2021-02-05 7:41 ` Hector Martin 'marcan'
2021-02-05 10:33 ` Arnd Bergmann
2021-02-05 10:33 ` Arnd Bergmann
2021-02-05 2:27 ` kernel test robot
2021-02-05 2:27 ` kernel test robot
2021-02-05 2:27 ` kernel test robot
2021-02-05 9:45 ` Hector Martin 'marcan'
2021-02-05 9:45 ` Hector Martin 'marcan'
2021-02-08 9:25 ` Marc Zyngier
2021-02-08 9:25 ` Marc Zyngier
2021-02-08 10:29 ` Arnd Bergmann
2021-02-08 10:29 ` Arnd Bergmann
2021-02-08 11:13 ` Hector Martin 'marcan'
2021-02-08 11:13 ` Hector Martin 'marcan'
2021-02-08 11:21 ` Arnd Bergmann
2021-02-08 11:21 ` Arnd Bergmann
2021-02-08 11:36 ` Marc Zyngier
2021-02-08 11:36 ` Marc Zyngier
2021-02-08 12:17 ` Arnd Bergmann
2021-02-08 12:17 ` Arnd Bergmann
2021-02-08 15:31 ` Hector Martin
2021-02-08 15:31 ` Hector Martin
2021-02-09 6:20 ` Hector Martin
2021-02-09 6:20 ` Hector Martin
2021-02-04 20:39 ` [PATCH 16/18] irqchip/apple-aic: Add SMP / IPI support Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 20:39 ` [PATCH 17/18] dt-bindings: display: add AAPL,simple-framebuffer Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 20:39 ` [PATCH 18/18] arm64: apple: Add initial Mac Mini 2020 (M1) devicetree Hector Martin
2021-02-04 20:39 ` Hector Martin
2021-02-04 21:29 ` Arnd Bergmann
2021-02-04 21:29 ` Arnd Bergmann
2021-02-04 21:44 ` Hector Martin 'marcan'
2021-02-04 21:44 ` Hector Martin 'marcan'
2021-02-04 23:08 ` Arnd Bergmann
2021-02-04 23:08 ` Arnd Bergmann
2021-02-05 7:11 ` Hector Martin 'marcan'
2021-02-05 7:11 ` Hector Martin 'marcan'
2021-02-05 12:43 ` Arnd Bergmann
2021-02-05 12:43 ` Arnd Bergmann
2021-02-08 11:04 ` Krzysztof Kozlowski
2021-02-08 11:04 ` Krzysztof Kozlowski
2021-02-08 11:56 ` Hector Martin 'marcan'
2021-02-08 11:56 ` Hector Martin 'marcan'
2021-02-08 12:13 ` Krzysztof Kozlowski
2021-02-08 12:13 ` Krzysztof Kozlowski
2021-02-08 12:40 ` Arnd Bergmann
2021-02-08 12:40 ` Arnd Bergmann
2021-02-08 14:12 ` Hector Martin
2021-02-08 14:12 ` Hector Martin
2021-02-08 17:58 ` Rob Herring
2021-02-08 17:58 ` Rob Herring
2021-02-09 0:32 ` Hector Martin
2021-02-09 0:32 ` Hector Martin
2021-02-08 19:14 ` Rob Herring
2021-02-08 19:14 ` Rob Herring
2021-02-09 0:49 ` Hector Martin
2021-02-09 0:49 ` Hector Martin
2021-02-09 2:05 ` Rob Herring
2021-02-09 2:05 ` Rob Herring
2021-02-10 10:19 ` Tony Lindgren
2021-02-10 10:19 ` Tony Lindgren
2021-02-10 11:07 ` Hector Martin
2021-02-10 11:07 ` Hector Martin
2021-02-10 11:34 ` Tony Lindgren
2021-02-10 11:34 ` Tony Lindgren
2021-02-10 11:43 ` Hector Martin
2021-02-10 11:43 ` Hector Martin
2021-02-10 12:24 ` Daniel Palmer
2021-02-10 12:24 ` Daniel Palmer
2021-02-10 12:24 ` Daniel Palmer
2021-02-10 12:54 ` Tony Lindgren
2021-02-10 12:54 ` Tony Lindgren
2021-02-10 12:56 ` Hector Martin
2021-02-10 12:56 ` Hector Martin
2021-02-10 12:55 ` Krzysztof Kozlowski
2021-02-10 12:55 ` Krzysztof Kozlowski
2021-02-10 13:19 ` Tony Lindgren
2021-02-10 13:19 ` Tony Lindgren
2021-02-10 13:25 ` Krzysztof Kozlowski
2021-02-10 13:25 ` Krzysztof Kozlowski
2021-02-08 12:27 ` Marc Zyngier
2021-02-08 12:27 ` Marc Zyngier
2021-02-08 14:53 ` Hector Martin
2021-02-08 14:53 ` Hector Martin
2021-02-08 15:36 ` Marc Zyngier
2021-02-08 15:36 ` Marc Zyngier
2021-02-04 22:43 ` [PATCH 00/18] Apple M1 SoC platform bring-up Arnd Bergmann
2021-02-04 22:43 ` Arnd Bergmann
2021-02-05 11:35 ` Hector Martin 'marcan'
2021-02-05 11:35 ` Hector Martin 'marcan'
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