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Message-ID: <27de5349-0bc1-74c3-518f-2dcdc1a8cfaf@csgroup.eu>
Date: Fri, 26 Mar 2021 07:18:41 +0100
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Will Deacon <will@...nel.org>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>, danielwa@...co.com,
robh@...nel.org, daniel@...pelevich.san-francisco.ca.us,
linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
linux-arch@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v2 6/7] cmdline: Gives architectures opportunity to use
generically defined boot cmdline manipulation
Le 25/03/2021 à 20:32, Will Deacon a écrit :
> On Thu, Mar 25, 2021 at 12:18:38PM +0100, Christophe Leroy wrote:
>>
>> - For ARM it means to append the bootloader arguments to the CONFIG_CMDLINE
>> - For Powerpc it means to append the CONFIG_CMDLINE to the bootloader arguments
>> - For SH it means to append the CONFIG_CMDLINE to the bootloader arguments
>> - For EFI it means to append the bootloader arguments to the CONFIG_CMDLINE
>> - For OF it means to append the CONFIG_CMDLINE to the bootloader arguments
>>
>> So what happens on ARM for instance when it selects CONFIG_OF for instance ?
>
> I think ARM gets different behaviour depending on whether it uses ATAGs or
> FDT.
As far as I can see, ARM uses either ATAGs only or both ATAGs and FDT. ATAGs is forced to 'y' when
USE_OF is set. Do I miss something ?
>
>> Or should we consider that EXTEND means APPEND or PREPEND, no matter which ?
>> Because EXTEND is for instance used for:
>>
>> config INITRAMFS_FORCE
>> bool "Ignore the initramfs passed by the bootloader"
>> depends on CMDLINE_EXTEND || CMDLINE_FORCE
>
> Oh man, I didn't spot that one :(
>
> I think I would make the generic options explicit: either APPEND or PREPEND.
> Then architectures which choose to define CMDLINE_EXTEND in their Kconfigs
> can select the generic option that matches their behaviour.
>
> INITRAMFS_FORCE sounds like it should depend on APPEND (assuming that means
> CONFIG_CMDLINE is appended to the bootloader arguments).
>
Christophe
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