[PATCH] arm64: kernel: do not mark reserved memory regions as IORESOURCE_BUSY

[Ard Biesheuvel]

On 24 January 2017 at 18:01, Will Deacon <will.deacon at arm.com> wrote:
> On Tue, Jan 24, 2017 at 05:11:40PM +0000, Ard Biesheuvel wrote:
>> Memory regions marked as NOMAP should not be used for general allocation
>> by the kernel, and should not even be covered by the linear mapping
>> (hence the name). However, drivers or other subsystems (such as ACPI)
>> that access the firmware directly may legally access them, which means
>> it is also reasonable for such drivers to claim them by invoking
>> request_resource(). Currently, this is prevented by the fact that arm64's
>> request_standard_resources() marks reserved regions as IORESOURCE_BUSY.
>>
>> So drop the IORESOURCE_BUSY flag from these requests.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>> ---
>>  arch/arm64/kernel/setup.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Did you find this my inspection, or has somebody reported a problem?
>

Hanjun (whom I forgot to cc) reported an issue with the ACPI EINJ
(error injection) code, which may call request_resource() on UEFI
reserved regions.