From: Thomas Huth <thuth@redhat.com>

While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This can be very confusing when switching between userspace
and kernelspace coding, or when dealing with uapi headers that
rather should use __ASSEMBLER__ instead. So let's standardize now
on the __ASSEMBLER__ macro that is provided by the compilers.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 Note: This patch has been split from an earlier patch series of mine
 to ease reviewing.

 include/xen/arm/interface.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/xen/arm/interface.h b/include/xen/arm/interface.h
index c3eada2642aa9..61360b89da405 100644
--- a/include/xen/arm/interface.h
+++ b/include/xen/arm/interface.h
@@ -30,7 +30,7 @@
 
 #define __HYPERVISOR_platform_op_raw __HYPERVISOR_platform_op
 
-#ifndef __ASSEMBLY__
+#ifndef __ASSEMBLER__
 /* Explicitly size integers that represent pfns in the interface with
  * Xen so that we can have one ABI that works for 32 and 64 bit guests.
  * Note that this means that the xen_pfn_t type may be capable of
-- 
2.53.0

On 21.04.26 16:27, Thomas Huth wrote:
> From: Thomas Huth <thuth@redhat.com>
> 
> While the GCC and Clang compilers already define __ASSEMBLER__
> automatically when compiling assembly code, __ASSEMBLY__ is a
> macro that only gets defined by the Makefiles in the kernel.
> This can be very confusing when switching between userspace
> and kernelspace coding, or when dealing with uapi headers that
> rather should use __ASSEMBLER__ instead. So let's standardize now
> on the __ASSEMBLER__ macro that is provided by the compilers.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen

On Tue, 21 Apr 2026, Thomas Huth wrote:
> From: Thomas Huth <thuth@redhat.com>
> 
> While the GCC and Clang compilers already define __ASSEMBLER__
> automatically when compiling assembly code, __ASSEMBLY__ is a
> macro that only gets defined by the Makefiles in the kernel.
> This can be very confusing when switching between userspace
> and kernelspace coding, or when dealing with uapi headers that
> rather should use __ASSEMBLER__ instead. So let's standardize now
> on the __ASSEMBLER__ macro that is provided by the compilers.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

I haven't been closely following the __ASSEMBLER__ vs __ASSEMBLY__
discussion. If there is general agreement to use __ASSEMBLER__ in
headers, I am happy to go along with that. Currently, I see more than
140 uses of __ASSEMBLY__ compared to fewer than 20 uses of
__ASSEMBLER__, but I'll defer to your judgment if the project is moving
in that direction.


> ---
>  Note: This patch has been split from an earlier patch series of mine
>  to ease reviewing.
> 
>  include/xen/arm/interface.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/xen/arm/interface.h b/include/xen/arm/interface.h
> index c3eada2642aa9..61360b89da405 100644
> --- a/include/xen/arm/interface.h
> +++ b/include/xen/arm/interface.h
> @@ -30,7 +30,7 @@
>  
>  #define __HYPERVISOR_platform_op_raw __HYPERVISOR_platform_op
>  
> -#ifndef __ASSEMBLY__
> +#ifndef __ASSEMBLER__
>  /* Explicitly size integers that represent pfns in the interface with
>   * Xen so that we can have one ABI that works for 32 and 64 bit guests.
>   * Note that this means that the xen_pfn_t type may be capable of
> -- 
> 2.53.0
>

On 22/04/2026 00.15, Stefano Stabellini wrote:
> On Tue, 21 Apr 2026, Thomas Huth wrote:
>> From: Thomas Huth <thuth@redhat.com>
>>
>> While the GCC and Clang compilers already define __ASSEMBLER__
>> automatically when compiling assembly code, __ASSEMBLY__ is a
>> macro that only gets defined by the Makefiles in the kernel.
>> This can be very confusing when switching between userspace
>> and kernelspace coding, or when dealing with uapi headers that
>> rather should use __ASSEMBLER__ instead. So let's standardize now
>> on the __ASSEMBLER__ macro that is provided by the compilers.
>>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
> 
> I haven't been closely following the __ASSEMBLER__ vs __ASSEMBLY__
> discussion. If there is general agreement to use __ASSEMBLER__ in
> headers, I am happy to go along with that. Currently, I see more than
> 140 uses of __ASSEMBLY__ compared to fewer than 20 uses of
> __ASSEMBLER__, but I'll defer to your judgment if the project is moving
> in that direction.

I assume you only counted the occurrences in the main include/ folder?
Please also take the arch/*/include/ folders into account:

thuth:~/devel/linux$ grep -r __ASSEMBLER__ arch/*/include/ | wc -l
1492
thuth:~/devel/linux$ grep -r __ASSEMBLY__ arch/*/include/ | wc -l
120

So most spots have been converted already. It would be great if you could 
help with the xen header!

  Thanks,
   Thomas