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

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

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);                           \

~Andrew