Re: [PATCH] ARM: zynq: Reserve correct amount of non-DMA RAM

From: Michal Simek
Date: Mon Nov 14 2016 - 10:11:23 EST


On 10.11.2016 10:57, Nathan Rossi wrote:
> On 10 November 2016 at 19:33, Nathan Rossi <nathan@xxxxxxxxxxxxxxx> wrote:
>> On 10 November 2016 at 18:41, Michal Simek <monstr@xxxxxxxxx> wrote:
>>> + Nathan
>>>
>>> 2016-10-31 17:26 GMT+01:00 Kyle Roeschley <kyle.roeschley@xxxxxx>:
>>>>
>>>> On Zynq, we haven't been reserving the correct amount of DMA-incapable
>>>> RAM to keep DMA away from it (per the Zynq TRM Section 4.1, it should be
>>>> the first 512k). In older kernels, this was masked by the
>>>> memblock_reserve call in arm_memblock_init(). Now, reserve the correct
>>>> amount excplicitly rather than relying on swapper_pg_dir, which is an
>>>> address and not a size anyway.
>>>>
>>>> Fixes: 46f5b96 ("ARM: zynq: Reserve not DMAable space in front of the
>>>> kernel")
>>>>
>>>> Signed-off-by: Kyle Roeschley <kyle.roeschley@xxxxxx>
>>
>> Tested-by: Nathan Rossi <nathan@xxxxxxxxxxxxxxx>
>>
>> For reference this causes problems with DEBUG_RODATA (which changed to
>
> Sorry typo -> s/causes/caused/, as in "... this [incorrect reserving
> of the lower 512K] caused ...".
>
> Regards,
> Nathan
>
>> default yes for CPU_V7 in v4.6) due to padding memory between
>> .head.text and .text, allowing memory below 0x80000 to be available
>> for allocation as non-reserved memory.
Applied to zynq/soc
https://github.com/Xilinx/linux-xlnx/commits/zynq/soc

Thanks,
Michal

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