[PATCH 3/3] ARM: errata 430973: move !ARCH_MULTIPLATFORM to Kconfig
ben.dooks at codethink.co.uk
Mon Jul 27 02:59:56 PDT 2015
On 27/07/15 02:14, Sebastian Reichel wrote:
> On Sun, Jul 26, 2015 at 11:51:45PM +0100, Russell King - ARM Linux
>> On Fri, Jul 24, 2015 at 02:16:06AM +0200, Sebastian Reichel
>>> On Thu, Jul 23, 2015 at 01:35:53PM +0100, Russell King - ARM
>>> Linux wrote:
>>>> On Thu, Jul 23, 2015 at 02:48:03AM +0200, Sebastian Reichel
>>>>> Having the !ARCH_MULTIPLATFORM dependency in the Kconfig
>>>>> file results in one option less to think about when
>>>>> configuring the kernel.
>>>>> -#if defined(CONFIG_ARM_ERRATA_430973) &&
>>>>> !defined(CONFIG_ARCH_MULTIPLATFORM) +#ifdef
>>>>> CONFIG_ARM_ERRATA_430973 teq r3, #0x00100000 @ only
>>>>> present in r1p* mrceq p15, 0, r0, c1, c0, 1 @ read aux
>>>>> control register orreq r0, r0, #(1 << 6) @ set IBE to 1
>>>> NAK. Please read the mailing list history, I'm not
>>>> repeating myself again on this. Thanks.
>>> It's a bit hard to search the mailing list history without a
>>> bit more information.
>> You were Cc'd on the previous round of review...
> But that discussion was about removing the check alltogether iirc.
> This patch does not remove the !ARCH_MULTIPLATFORM check. It just
> *moves* it from the sourcecode to the errata's Kconfig entry.
> The intention was to hide the Kconfig option on multiplatform
> kernels, since it's completely useless there after the N900
> boardcode has been changed (PATCH 1/3).
>>> I guess you prefer to just add the !ARCH_MULTIPLATFORM
>>> dependency to the Kconfig entry without removing the
>>> additional check in the code?
>> I was referring to the above change.
>> However, having discussed with Will Deacon and checked the
>> manuals, I think the change is okay after all: the auxillary
>> control register is banked on secure parts, and the bit we'll be
>> trying to change will be read-only in non-secure mode - and
>> importantly won't fault.
>> So, the change is fine, thanks.
> I think you missed the part adding the !ARCH_MULTIPLATFORM
> dependency in Kconfig for ARM_ERRATA_430973. I only removed the
> check in the sourcecode, since it is no longer required with the
> dependency being in Kconfig.
> So I guess there are 3 options now:
> 1. Add !ARCH_MULTIPLATFORM dependency to Kconfig, keep extra check
> in the sourcecode 2. Add !ARCH_MULTIPLATFORM dependency to Kconfig,
> remove extra check in the sourcecode 3. Remove !ARCH_MULTIPLATFORM
> dependency alltogether
> I will send an appropriate patch, if you tell me your preferred
This isn't the only place ARM_ERRATA_430973 is used, and if
you make it configurable on !ARCH_MULTIPLATFORM then it makes
it impossible to use a ARCH_MULTIPLATFORM kernel on something
that is an Cortex-A8.
Ben Dooks http://www.codethink.co.uk/
Senior Engineer Codethink - Providing Genius
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