Re: [PATCH 2/2] xen/arm: Simplify type handling for SMCCC declarations

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 24/02/2026 4:02 pm, Andrew Cooper wrote:
> On 24/02/2026 2:18 pm, Orzel, Michal wrote:
>> On 24/02/2026 13:45, Andrew Cooper wrote:
>>> There's no use creating a typed copy of a macro argument, simply to use it 
>>> to
>>> create a second typed copy.  Remove the indirection, halving the number of
>>> local variables created in scope.
>>>
>>> No functional change.
>>>
>>> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>>> ---
>>> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>>> CC: Julien Grall <julien@xxxxxxx>
>>> CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
>>> CC: Bertrand Marquis <bertrand.marquis@xxxxxxx>
>>> CC: Michal Orzel <michal.orzel@xxxxxxx>
>>>
>>> This also makes them clearly elliglbe for converstion to auto, where they
>>> weren't before (typeof expression not being that of the RHS).
>>> ---
>>>  xen/arch/arm/include/asm/smccc.h | 21 +++++++--------------
>>>  1 file changed, 7 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/xen/arch/arm/include/asm/smccc.h 
>>> b/xen/arch/arm/include/asm/smccc.h
>>> index 347c4526d12a..7e90b0b56550 100644
>>> --- a/xen/arch/arm/include/asm/smccc.h
>>> +++ b/xen/arch/arm/include/asm/smccc.h
>>> @@ -113,39 +113,32 @@ struct arm_smccc_res {
>>>      register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0)
>>>  
>>>  #define __declare_arg_1(a0, a1, res)                        \
>>> -    typeof(a1) __a1 = (a1);                                 \
>>>      __declare_arg_0(a0, res);                               \
>>> -    register typeof(a1)     arg1 ASM_REG(1) = __a1
>>> +    register typeof(a1)     arg1 ASM_REG(1) = a1
>>>  
>>>  #define __declare_arg_2(a0, a1, a2, res)                    \
>>> -    typeof(a1) __a1 = (a1);                                 \
>>>      __declare_arg_1(a0, a1, res);                           \
>>> -    register typeof(a2)     arg2 ASM_REG(2) = __a2
>>> +    register typeof(a2)     arg2 ASM_REG(2) = a2
>> Here you fix the issue introduced in patch 1/2 :) You drop typeof(a1) and
>> replace it with correct typeof(a2).
>>
>> Provided this patch is rebased on fixed 1/2:
>> Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
> Thanks.  Sadly, ECLAIR rejects this change.  I need to retain the
> brackets around the macro parameter after move, so this kind of
> incremental diff:
>
>> @@ -114,7 +114,7 @@ struct arm_smccc_res {
>>  
>>  #define __declare_arg_1(a0, a1, res)                        \
>>      __declare_arg_0(a0, res);                               \
>> -    register typeof(a1)     arg1 ASM_REG(1) = a1
>> +    register typeof(a1)     arg1 ASM_REG(1) = (a1)
>>  
>>  #define __declare_arg_2(a0, a1, a2, res)                    \
>>      __declare_arg_1(a0, a1, res);                           \

Passing pipeline:

https://gitlab.com/xen-project/hardware/xen-staging/-/jobs/13244194836

~Andrew