All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kernel@collabora.com
Subject: Re: [RFC 1/1] ARM: Drop !ARCH_MULTIPLATFORM dependency from Cortex A8/9 erratas
Date: Fri, 9 Dec 2022 18:45:34 +0000	[thread overview]
Message-ID: <Y5OCTseqVQ+AcMqm@shell.armlinux.org.uk> (raw)
In-Reply-To: <20221209182000.549179-1-sebastian.reichel@collabora.com>

On Fri, Dec 09, 2022 at 07:20:00PM +0100, Sebastian Reichel wrote:
> All the erratas for more recent CPUs (Cortex A15/A12/A17) do not
> require !ARCH_MULTIPLATFORM, since there is runtime detection of
> effected CPUs in arch/arm/mm/proc-v7.S.
> 
> Errata config options for the older Cortex A8/A9 CPUs have the
> !ARCH_MULTIPLATFORM dependency, but the CPUs are also runtime
> detected. Since there is runtime detection, it should be fine
> to enable the erratas for a multi platform kernel.
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
> For me the most likely explanation that this has not yet happened is
> me missing an important detail, so I sent it as RFC. If you point it
> out I will try to document the reason.

IIRC, the reason these are marked with !ARCH_MULTIPLATFORM is for when
the kernel is running in the non-secure world - the accessed registers
may prevent platforms booting. However, it was a long time ago and I
don't remember clearly now.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

_______________________________________________
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: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kernel@collabora.com
Subject: Re: [RFC 1/1] ARM: Drop !ARCH_MULTIPLATFORM dependency from Cortex A8/9 erratas
Date: Fri, 9 Dec 2022 18:45:34 +0000	[thread overview]
Message-ID: <Y5OCTseqVQ+AcMqm@shell.armlinux.org.uk> (raw)
In-Reply-To: <20221209182000.549179-1-sebastian.reichel@collabora.com>

On Fri, Dec 09, 2022 at 07:20:00PM +0100, Sebastian Reichel wrote:
> All the erratas for more recent CPUs (Cortex A15/A12/A17) do not
> require !ARCH_MULTIPLATFORM, since there is runtime detection of
> effected CPUs in arch/arm/mm/proc-v7.S.
> 
> Errata config options for the older Cortex A8/A9 CPUs have the
> !ARCH_MULTIPLATFORM dependency, but the CPUs are also runtime
> detected. Since there is runtime detection, it should be fine
> to enable the erratas for a multi platform kernel.
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
> For me the most likely explanation that this has not yet happened is
> me missing an important detail, so I sent it as RFC. If you point it
> out I will try to document the reason.

IIRC, the reason these are marked with !ARCH_MULTIPLATFORM is for when
the kernel is running in the non-secure world - the accessed registers
may prevent platforms booting. However, it was a long time ago and I
don't remember clearly now.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

  reply	other threads:[~2022-12-09 18:46 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-09 18:20 [RFC 1/1] ARM: Drop !ARCH_MULTIPLATFORM dependency from Cortex A8/9 erratas Sebastian Reichel
2022-12-09 18:20 ` Sebastian Reichel
2022-12-09 18:45 ` Russell King (Oracle) [this message]
2022-12-09 18:45   ` Russell King (Oracle)
2022-12-09 21:36   ` Arnd Bergmann
2022-12-09 21:36     ` Arnd Bergmann
2022-12-10  2:55     ` Sebastian Reichel
2022-12-10  2:55       ` Sebastian Reichel

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Y5OCTseqVQ+AcMqm@shell.armlinux.org.uk \
    --to=linux@armlinux.org.uk \
    --cc=arnd@arndb.de \
    --cc=kernel@collabora.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sebastian.reichel@collabora.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.