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[PATCH 1/2] xen/arm: Simplify SMCCC handling by reusing __declare_arg_$()

Andrew Cooper posted 2 patches 6 days, 14 hours ago
[PATCH 1/2] xen/arm: Simplify SMCCC handling by reusing __declare_arg_$()
Posted by Andrew Cooper 6 days, 14 hours ago 
Now that the type handling is entirely uniform, it's easier to see that
__declare_arg_3() can use __declare_arg_2() and so on, just like the larger
__declare_arg_$()'s already do.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien@xen.org>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
CC: Bertrand Marquis <bertrand.marquis@arm.com>
CC: Michal Orzel <michal.orzel@amd.com>
---
 xen/arch/arm/include/asm/smccc.h | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/xen/arch/arm/include/asm/smccc.h b/xen/arch/arm/include/asm/smccc.h
index 5b30dd57b69d..347c4526d12a 100644
--- a/xen/arch/arm/include/asm/smccc.h
+++ b/xen/arch/arm/include/asm/smccc.h
@@ -114,26 +114,17 @@ struct arm_smccc_res {
 
 #define __declare_arg_1(a0, a1, res)                        \
     typeof(a1) __a1 = (a1);                                 \
-    struct arm_smccc_res    *___res = (res);                \
-    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
+    __declare_arg_0(a0, res);                               \
     register typeof(a1)     arg1 ASM_REG(1) = __a1
 
 #define __declare_arg_2(a0, a1, a2, res)                    \
     typeof(a1) __a1 = (a1);                                 \
-    typeof(a2) __a2 = (a2);                                 \
-    struct arm_smccc_res    *___res = (res);                \
-    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
-    register typeof(a1)     arg1 ASM_REG(1) = __a1;         \
+    __declare_arg_1(a0, a1, res);                           \
     register typeof(a2)     arg2 ASM_REG(2) = __a2
 
 #define __declare_arg_3(a0, a1, a2, a3, res)                \
     typeof(a1) __a1 = (a1);                                 \
-    typeof(a2) __a2 = (a2);                                 \
-    typeof(a3) __a3 = (a3);                                 \
-    struct arm_smccc_res    *___res = (res);                \
-    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
-    register typeof(a1)     arg1 ASM_REG(1) = __a1;         \
-    register typeof(a2)     arg2 ASM_REG(2) = __a2;         \
+    __declare_arg_2(a0, a1, a2, res);                       \
     register typeof(a3)     arg3 ASM_REG(3) = __a3
 
 #define __declare_arg_4(a0, a1, a2, a3, a4, res)        \
-- 
2.39.5
Re: [PATCH 1/2] xen/arm: Simplify SMCCC handling by reusing __declare_arg_$()
Posted by Orzel, Michal 6 days, 13 hours ago 

On 24/02/2026 13:45, Andrew Cooper wrote:
> Now that the type handling is entirely uniform, it's easier to see that
> __declare_arg_3() can use __declare_arg_2() and so on, just like the larger
> __declare_arg_$()'s already do.
> 
> No functional change.
This patch won't build.

> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> CC: Stefano Stabellini <sstabellini@kernel.org>
> CC: Julien Grall <julien@xen.org>
> CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
> CC: Bertrand Marquis <bertrand.marquis@arm.com>
> CC: Michal Orzel <michal.orzel@amd.com>
> ---
>  xen/arch/arm/include/asm/smccc.h | 15 +++------------
>  1 file changed, 3 insertions(+), 12 deletions(-)
> 
> diff --git a/xen/arch/arm/include/asm/smccc.h b/xen/arch/arm/include/asm/smccc.h
> index 5b30dd57b69d..347c4526d12a 100644
> --- a/xen/arch/arm/include/asm/smccc.h
> +++ b/xen/arch/arm/include/asm/smccc.h
> @@ -114,26 +114,17 @@ struct arm_smccc_res {
>  
>  #define __declare_arg_1(a0, a1, res)                        \
>      typeof(a1) __a1 = (a1);                                 \
> -    struct arm_smccc_res    *___res = (res);                \
> -    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
> +    __declare_arg_0(a0, res);                               \
>      register typeof(a1)     arg1 ASM_REG(1) = __a1
>  
>  #define __declare_arg_2(a0, a1, a2, res)                    \
>      typeof(a1) __a1 = (a1);                                 \
You should remove this line and ...

> -    typeof(a2) __a2 = (a2);                                 \
keep this line.

> -    struct arm_smccc_res    *___res = (res);                \
> -    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
> -    register typeof(a1)     arg1 ASM_REG(1) = __a1;         \
> +    __declare_arg_1(a0, a1, res);                           \
>      register typeof(a2)     arg2 ASM_REG(2) = __a2
>  
>  #define __declare_arg_3(a0, a1, a2, a3, res)                \
>      typeof(a1) __a1 = (a1);                                 \
> -    typeof(a2) __a2 = (a2);                                 \
Same here.

> -    typeof(a3) __a3 = (a3);                                 \
> -    struct arm_smccc_res    *___res = (res);                \
> -    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
> -    register typeof(a1)     arg1 ASM_REG(1) = __a1;         \
> -    register typeof(a2)     arg2 ASM_REG(2) = __a2;         \
> +    __declare_arg_2(a0, a1, a2, res);                       \
>      register typeof(a3)     arg3 ASM_REG(3) = __a3
>  
>  #define __declare_arg_4(a0, a1, a2, a3, a4, res)        \

In principal, with the remarks addressed:
Reviewed-by: Michal Orzel <michal.orzel@amd.com>

~Michal
Re: [PATCH 1/2] xen/arm: Simplify SMCCC handling by reusing __declare_arg_$()
Posted by Andrew Cooper 6 days, 13 hours ago 
On 24/02/2026 2:14 pm, Orzel, Michal wrote:
>
> On 24/02/2026 13:45, Andrew Cooper wrote:
>> Now that the type handling is entirely uniform, it's easier to see that
>> __declare_arg_3() can use __declare_arg_2() and so on, just like the larger
>> __declare_arg_$()'s already do.
>>
>> No functional change.
> This patch won't build.
>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>> ---
>> CC: Stefano Stabellini <sstabellini@kernel.org>
>> CC: Julien Grall <julien@xen.org>
>> CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
>> CC: Bertrand Marquis <bertrand.marquis@arm.com>
>> CC: Michal Orzel <michal.orzel@amd.com>
>> ---
>>  xen/arch/arm/include/asm/smccc.h | 15 +++------------
>>  1 file changed, 3 insertions(+), 12 deletions(-)
>>
>> diff --git a/xen/arch/arm/include/asm/smccc.h b/xen/arch/arm/include/asm/smccc.h
>> index 5b30dd57b69d..347c4526d12a 100644
>> --- a/xen/arch/arm/include/asm/smccc.h
>> +++ b/xen/arch/arm/include/asm/smccc.h
>> @@ -114,26 +114,17 @@ struct arm_smccc_res {
>>  
>>  #define __declare_arg_1(a0, a1, res)                        \
>>      typeof(a1) __a1 = (a1);                                 \
>> -    struct arm_smccc_res    *___res = (res);                \
>> -    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
>> +    __declare_arg_0(a0, res);                               \
>>      register typeof(a1)     arg1 ASM_REG(1) = __a1
>>  
>>  #define __declare_arg_2(a0, a1, a2, res)                    \
>>      typeof(a1) __a1 = (a1);                                 \
> You should remove this line and ...
>
>> -    typeof(a2) __a2 = (a2);                                 \
> keep this line.
>
>> -    struct arm_smccc_res    *___res = (res);                \
>> -    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
>> -    register typeof(a1)     arg1 ASM_REG(1) = __a1;         \
>> +    __declare_arg_1(a0, a1, res);                           \
>>      register typeof(a2)     arg2 ASM_REG(2) = __a2
>>  
>>  #define __declare_arg_3(a0, a1, a2, a3, res)                \
>>      typeof(a1) __a1 = (a1);                                 \
>> -    typeof(a2) __a2 = (a2);                                 \
> Same here.

Hmm - it built for me.  I'd better figure out why I missed it first.

With the second patch, these disappear, which is why _that_ builds.

>
>> -    typeof(a3) __a3 = (a3);                                 \
>> -    struct arm_smccc_res    *___res = (res);                \
>> -    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
>> -    register typeof(a1)     arg1 ASM_REG(1) = __a1;         \
>> -    register typeof(a2)     arg2 ASM_REG(2) = __a2;         \
>> +    __declare_arg_2(a0, a1, a2, res);                       \
>>      register typeof(a3)     arg3 ASM_REG(3) = __a3
>>  
>>  #define __declare_arg_4(a0, a1, a2, a3, a4, res)        \
> In principal, with the remarks addressed:
> Reviewed-by: Michal Orzel <michal.orzel@amd.com>

Thanks.

~Andrew
Re: [PATCH 1/2] xen/arm: Simplify SMCCC handling by reusing __declare_arg_$()
Posted by Andrew Cooper 6 days, 13 hours ago 
On 24/02/2026 2:17 pm, Andrew Cooper wrote:
> On 24/02/2026 2:14 pm, Orzel, Michal wrote:
>> On 24/02/2026 13:45, Andrew Cooper wrote:
>>> Now that the type handling is entirely uniform, it's easier to see that
>>> __declare_arg_3() can use __declare_arg_2() and so on, just like the larger
>>> __declare_arg_$()'s already do.
>>>
>>> No functional change.
>> This patch won't build.
>>
>>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>>> ---
>>> CC: Stefano Stabellini <sstabellini@kernel.org>
>>> CC: Julien Grall <julien@xen.org>
>>> CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
>>> CC: Bertrand Marquis <bertrand.marquis@arm.com>
>>> CC: Michal Orzel <michal.orzel@amd.com>
>>> ---
>>>  xen/arch/arm/include/asm/smccc.h | 15 +++------------
>>>  1 file changed, 3 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/xen/arch/arm/include/asm/smccc.h b/xen/arch/arm/include/asm/smccc.h
>>> index 5b30dd57b69d..347c4526d12a 100644
>>> --- a/xen/arch/arm/include/asm/smccc.h
>>> +++ b/xen/arch/arm/include/asm/smccc.h
>>> @@ -114,26 +114,17 @@ struct arm_smccc_res {
>>>  
>>>  #define __declare_arg_1(a0, a1, res)                        \
>>>      typeof(a1) __a1 = (a1);                                 \
>>> -    struct arm_smccc_res    *___res = (res);                \
>>> -    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
>>> +    __declare_arg_0(a0, res);                               \
>>>      register typeof(a1)     arg1 ASM_REG(1) = __a1
>>>  
>>>  #define __declare_arg_2(a0, a1, a2, res)                    \
>>>      typeof(a1) __a1 = (a1);                                 \
>> You should remove this line and ...
>>
>>> -    typeof(a2) __a2 = (a2);                                 \
>> keep this line.
>>
>>> -    struct arm_smccc_res    *___res = (res);                \
>>> -    register unsigned long  arg0 ASM_REG(0) = (uint32_t)(a0);\
>>> -    register typeof(a1)     arg1 ASM_REG(1) = __a1;         \
>>> +    __declare_arg_1(a0, a1, res);                           \
>>>      register typeof(a2)     arg2 ASM_REG(2) = __a2
>>>  
>>>  #define __declare_arg_3(a0, a1, a2, a3, res)                \
>>>      typeof(a1) __a1 = (a1);                                 \
>>> -    typeof(a2) __a2 = (a2);                                 \
>> Same here.
> Hmm - it built for me.  I'd better figure out why I missed it first.

Ah - a last minute refactor, and I didn't build test on this commit
boundary.

Fixed.  Thanks.

~Andrew

Patchew 2.1-devel-ea86937

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