Re: [PATCH v4] ARM: early fixmap support for earlycon

From: Ard Biesheuvel
Date: Wed Jun 17 2015 - 05:34:01 EST

On 17 June 2015 at 01:22, Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote:
> On 06/16/2015 02:51 PM, Stefan Agner wrote:
>> Add early fixmap support, initially to support permanent, fixed
>> mapping support for early console. A temporary, early pte is
>> created which is migrated to a permanent mapping in paging_init.
>> This is also needed since the attributes may change as the memory
>> types are initialized. The 3MiB range of fixmap spans two pte
>> tables, but currently only one pte is created for early fixmap
>> support.
>> Re-add FIX_KMAP_BEGIN to the index calculation in highmem.c since
>> the index for kmap does not start at zero anymore. This reverts
>> 4221e2e6b316 ("ARM: 8031/1: fixmap: remove FIX_KMAP_BEGIN and
>> FIX_KMAP_END") to some extent.
>> Cc: Mark Salter <msalter@xxxxxxxxxx>
>> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
>> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
>> Cc: Laura Abbott <lauraa@xxxxxxxxxxxxxx>
>> Cc: Arnd Bergmann <arnd@xxxxxxxx>
>> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
>> Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
> Works on msm_serial.
> Tested-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>

I gave this a spin as well, on Arndale, with /chosen/stdout-path set
to &serial_2 and just 'earlycon' (without value) passed on the
command line, and it works fine.

Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
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