From: Laurent Vivier <laurent@vivier.eu>
To: Greg KH <greg@kroah.com>
Cc: linux-kernel@vger.kernel.org, linux-rtc@vger.kernel.org,
Alessandro Zummo <a.zummo@towertech.it>,
Jiaxun Yang <jiaxun.yang@flygoat.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
linux-m68k@lists.linux-m68k.org, Arnd Bergmann <arnd@arndb.de>,
Thomas Gleixner <tglx@linutronix.de>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Stephen Boyd <sboyd@kernel.org>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
John Stultz <john.stultz@linaro.org>,
stable@vger.kernel.org
Subject: Re: [PATCH v12 2/5] tty: goldfish: introduce gf_ioread32()/gf_iowrite32()
Date: Wed, 26 Jan 2022 18:32:08 +0100 [thread overview]
Message-ID: <e4e1995c-4fc2-96b7-c732-93aa67207802@vivier.eu> (raw)
In-Reply-To: <YfFPjOEELiTWr2uj@kroah.com>
Le 26/01/2022 à 14:41, Greg KH a écrit :
> On Fri, Jan 21, 2022 at 09:07:35PM +0100, Laurent Vivier wrote:
>> Revert
>> commit da31de35cd2f ("tty: goldfish: use __raw_writel()/__raw_readl()")
>
> Why?
>
>> and define gf_ioread32()/gf_iowrite32() to be able to use accessors
>> defined by the architecture.
>
> What does this do?
>
>>
>> Cc: stable@vger.kernel.org # v5.11+
>> Fixes: da31de35cd2f ("tty: goldfish: use __raw_writel()/__raw_readl()")
>> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
>> ---
>> drivers/tty/goldfish.c | 20 ++++++++++----------
>> include/linux/goldfish.h | 15 +++++++++++----
>> 2 files changed, 21 insertions(+), 14 deletions(-)
...
>> --
>> 2.34.1
>>
>
> This feels like a step backwards. Why keep this level of indirection
> for no good reason?
>
It was proposed by Arnd on my previous iteration of the series when I wanted to update goldfish-rtc
in the same way:
https://lore.kernel.org/all/CAK8P3a1H6-sd_+FqnOq0Zhj=L51EWuW5VCcYeTENcp3+PkTC4Q@mail.gmail.com/
Keeping __raw_XXX() functions works on most of the cases except if the current CPU endianness can
differ from the architecture one (like a ppc64le kernel (little-endian) running a ppc64 machine
(big-endian)).
The best solution would be to update QEMU to set the device as a little-endian one, but google
didn't merge its implemention in upstream QEMU and this would break all other OSes using goldfish
devices on big-endian architectures.
Thanks,
Laurent
next prev parent reply other threads:[~2022-01-26 17:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-21 20:07 [PATCH v12 0/5] m68k: Add Virtual M68k Machine Laurent Vivier
2022-01-21 20:07 ` [PATCH v12 1/5] m68k: add asm/config.h Laurent Vivier
2022-01-21 20:07 ` [PATCH v12 2/5] tty: goldfish: introduce gf_ioread32()/gf_iowrite32() Laurent Vivier
2022-01-26 13:41 ` Greg KH
2022-01-26 14:15 ` Arnd Bergmann
2022-01-26 17:32 ` Laurent Vivier [this message]
2022-01-21 20:07 ` [PATCH v12 3/5] rtc: goldfish: use gf_ioread32()/gf_iowrite32() Laurent Vivier
2022-01-21 20:07 ` [PATCH v12 4/5] clocksource/drivers: Add a goldfish-timer clocksource Laurent Vivier
2022-01-26 11:55 ` Daniel Lezcano
2022-01-26 17:14 ` Laurent Vivier
2022-01-26 17:25 ` Daniel Lezcano
2022-01-21 20:07 ` [PATCH v12 5/5] m68k: introduce a virtual m68k machine Laurent Vivier
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