Re: [edk2-devel] [PATCH v2 1/1] ArmPkg: Fix uninitialised variable in ArmMmuStandaloneMmLib

["Ard Biesheuvel" <ardb@kernel.org>]

On Fri, 26 Feb 2021 at 11:58, Sughosh Ganu <sughosh.ganu@linaro.org> wrote:
>
>
> On Thu, 25 Feb 2021 at 22:41, Sami Mujawar <sami.mujawar@arm.com> wrote:
>>
>> The following patches added support for StandaloneMM using FF-A:
>> 9da5ee116a28 ArmPkg: Allow FF-A calls to set memory region's attributes
>> 0e43e02b9bd8 ArmPkg: Allow FF-A calls to get memory region's attributes
>>
>> However, in the error handling logic for the Get/Set Memory attributes,
>> the CLANG compiler reports that a status variable could be used without
>> initialisation. This issue is a false positive and is not seen with GCC.
>>
>> The Get/Set Memory attributes operation is atomic and therefore an
>> FFA_INTERRUPT or FFA_SUCCESS response is not expected in response
>> to FFA_MSG_SEND_DIRECT_REQ. So the remaining cases that could occur
>> are:
>>  - the target sends FFA_MSG_SEND_DIRECT_RESP with a success or
>>    failure code.
>>  or
>>  - FFA_MSG_SEND_DIRECT_REQ transmission failure.
>>
>> Therefore,
>>  - reorder the error handling conditions such that it prevents the
>>    uninitialised variable issue being flagged by CLANG.
>>  - move the repetitive code to a static helper function and add
>>    documentation at the appropriate places.
>>  - fix error handling in functions that invoke GetMemoryPermissions().
>>
>> Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
>> ---
>> The changes can be seen at:
>> https://github.com/samimujawar/edk2/tree/1657_stmm_ffa_fix_unused_var_v2
>
>
>  Tested the changes on the StandaloneMm image on the Qemu platform.
>
> Tested-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> Reviewed-by: Sughosh Ganu <sughosh.ganu@linaro.org>
>

Thanks. Sami, can you confirm that this patch fixes the CI failure I
reported to you in private? If so, I intend to merge this during the
freeze (assuming Liming is ok with that)