From: Giulio Benetti <giulio.benetti@benettiengineering.com>
To: Vladimir Murzin <vladimir.murzin@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Cc: "Russell King" <linux@armlinux.org.uk>,
"Arnd Bergmann" <arnd@arndb.de>,
"Linus Walleij" <linus.walleij@linaro.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
"Ard Biesheuvel" <ardb@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"Anshuman Khandual" <anshuman.khandual@arm.com>,
"Geert Uytterhoeven" <geert+renesas@glider.be>,
"Mike Rapoport" <rppt@kernel.org>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Lukas Bulwahn" <lukas.bulwahn@gmail.com>
Subject: Re: [PATCH] ARM: Kconfig: improve ARM_SINGLE_ARMV7M description with Cortex M7
Date: Fri, 3 Dec 2021 18:03:34 +0100 [thread overview]
Message-ID: <252614ac-04cc-8ac8-c226-4245088d8952@benettiengineering.com> (raw)
In-Reply-To: <ea2679ec-9bfd-6a78-a82d-7b160350ddfb@arm.com>
On 03/12/21 18:01, Vladimir Murzin wrote:
> On 12/3/21 4:41 PM, Giulio Benetti wrote:
>> Hi Vladimir,
>>
>> On 03/12/21 10:30, Vladimir Murzin wrote:
>>> On 12/2/21 10:20 PM, Giulio Benetti wrote:
>>>> ARM_SINGLE_ARMV7M implies Arm Cortex M7 too, so let's add it to
>>>> description with M0/M3/M4.
>>>
>>> Well it also implies M33 and M55. I'd suggest drop specific implementations
>>> from description - so we do not need to update it each time new compatible
>>> core is released. To account newest cores like M33 and M55 you can rephrase
>>> to:
>>> - ARMv7-M/v8-M
>>
>> This ^^^ is ok for me. Also, I don't see any M0 used at the moment so no ARMv6-M makes sense, if any in the future we can update. I see M3,M4,M7 for the moment, so ARMv7-M. But at the moment no ARMv8-M, or am I wrong?
>
> We already support PMSAv8 which is ARMv8-M, M33/M55 is in flight [1].
Ah, I've missed that. And great for M33!
>> Maybe it would be better to add ARMv8-M when there will really be the support, considering also that ARM_SINGLE_ARMV7M is a bit ambiguous to be used with ARMv8-M. So maybe that could be modified too when an ARMv8-M is added.
>>
>> What do you think about this?
>
> Well, I prefer to touch this as rare as possible, and if we touch
> it then ensure we do not need to touch it for a long time ;)
>
> Look at A-class cores,
>
> config ARCH_MULTI_V7
> bool "ARMv7 based platforms (Cortex-A, PJ4, Scorpion, Krait)"
>
> it doesn't mention ARMv8, yet it is pretty much possible to run it
> on some cores either bare-metal or as a guest (just look under
> arch/arm/include/asm/cputype.h)
Ah yeah, thanks for pointing, then I'm going with ARMv7-M/v8-M
> These are just config options, not a legal deeds...
+1
Thank you
Best regards
--
Giulio Benetti
Benetti Engineering sas
> [1] https://lore.kernel.org/linux-arm-kernel/20211201132908.106711-1-vladimir.murzin@arm.com/T/
>
> Cheers
> Vladimir
>
>>
>> Best regards
>
next prev parent reply other threads:[~2021-12-03 17:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-02 22:20 [PATCH] ARM: Kconfig: improve ARM_SINGLE_ARMV7M description with Cortex M7 Giulio Benetti
2021-12-03 9:30 ` Vladimir Murzin
2021-12-03 16:41 ` Giulio Benetti
2021-12-03 17:01 ` Vladimir Murzin
2021-12-03 17:03 ` Giulio Benetti [this message]
2021-12-03 17:09 ` [PATCH] ARM: Kconfig: improve ARM_SINGLE_ARMV7M with ARMv8-M too Giulio Benetti
2021-12-03 17:12 ` Vladimir Murzin
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