From: Thomas Huth <thuth@redhat.com>

In the very early kernel 1.x days, assembler files were pre-processed
with the "-traditional" flag. With kernel 1.1.85, the sparc subsystem
was changed to use "-ansi" instead while the other parts of the kernel
continued to use "-traditional". That "-traditional" got removed from
the other architectures in the course of time, but the sparc part
kept the "-ansi" until today.

This is bad since it comes with some disadvantages nowadays: You have
to make sure to not include any header that contains a "//" C++ comment
by accident (there are now some in the tree that use these for SPDX
identifiers for example), and with "-ansi" we also do not get the
pre-defined __ASSEMBLER__ macro which we'd like to use instead of the
kernel-only __ASSEMBLY__ macro in the future.

Since there does not seem to be any compelling reason anymore to use
"-ansi" nowadays, let's simply drop the "-ansi" flag from the sparc
subsystem now to get rid of those disadvantages.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 Note: I've only compile-tested this patch. No runtime testing done.

 arch/sparc/kernel/Makefile | 2 --
 arch/sparc/lib/Makefile    | 2 +-
 arch/sparc/mm/Makefile     | 2 --
 arch/sparc/prom/Makefile   | 1 -
 4 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index 36f2727e1445d..22170d4f8e060 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -4,8 +4,6 @@
 # Makefile for the linux kernel.
 #
 
-asflags-y := -ansi
-
 # Undefine sparc when processing vmlinux.lds - it is used
 # And teach CPP we are doing $(BITS) builds (for this case)
 CPPFLAGS_vmlinux.lds := -Usparc -m$(BITS)
diff --git a/arch/sparc/lib/Makefile b/arch/sparc/lib/Makefile
index ee5091dd67ed7..783bdec0d7be0 100644
--- a/arch/sparc/lib/Makefile
+++ b/arch/sparc/lib/Makefile
@@ -2,7 +2,7 @@
 # Makefile for Sparc library files..
 #
 
-asflags-y := -ansi -DST_DIV0=0x02
+asflags-y := -DST_DIV0=0x02
 
 lib-$(CONFIG_SPARC32) += ashrdi3.o
 lib-$(CONFIG_SPARC32) += memcpy.o memset.o
diff --git a/arch/sparc/mm/Makefile b/arch/sparc/mm/Makefile
index 2d1752108d779..e9d232561c82a 100644
--- a/arch/sparc/mm/Makefile
+++ b/arch/sparc/mm/Makefile
@@ -2,8 +2,6 @@
 # Makefile for the linux Sparc-specific parts of the memory manager.
 #
 
-asflags-y := -ansi
-
 obj-$(CONFIG_SPARC64)   += ultra.o tlb.o tsb.o
 obj-y                   += fault_$(BITS).o
 obj-y                   += init_$(BITS).o
diff --git a/arch/sparc/prom/Makefile b/arch/sparc/prom/Makefile
index a1adc75d80551..92db8bb4ad4cd 100644
--- a/arch/sparc/prom/Makefile
+++ b/arch/sparc/prom/Makefile
@@ -2,7 +2,6 @@
 # Makefile for the Sun Boot PROM interface library under
 # Linux.
 #
-asflags := -ansi
 
 lib-y                 := bootstr_$(BITS).o
 lib-y                 += init_$(BITS).o
-- 
2.50.1

On 2025-08-05 11:25, Thomas Huth wrote:
> From: Thomas Huth <thuth@redhat.com>
> 
> In the very early kernel 1.x days, assembler files were pre-processed
> with the "-traditional" flag. With kernel 1.1.85, the sparc subsystem
> was changed to use "-ansi" instead while the other parts of the kernel
> continued to use "-traditional". That "-traditional" got removed from
> the other architectures in the course of time, but the sparc part
> kept the "-ansi" until today.
> 
> This is bad since it comes with some disadvantages nowadays: You have
> to make sure to not include any header that contains a "//" C++ comment
> by accident (there are now some in the tree that use these for SPDX
> identifiers for example), and with "-ansi" we also do not get the
> pre-defined __ASSEMBLER__ macro which we'd like to use instead of the
> kernel-only __ASSEMBLY__ macro in the future.
> 
> Since there does not seem to be any compelling reason anymore to use
> "-ansi" nowadays, let's simply drop the "-ansi" flag from the sparc
> subsystem now to get rid of those disadvantages.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  Note: I've only compile-tested this patch. No runtime testing done.
> 
>  arch/sparc/kernel/Makefile | 2 --
>  arch/sparc/lib/Makefile    | 2 +-
>  arch/sparc/mm/Makefile     | 2 --
>  arch/sparc/prom/Makefile   | 1 -
>  4 files changed, 1 insertion(+), 6 deletions(-)

Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Tested-by: Andreas Larsson <andreas@gaisler.com>

Picking this up to my for-next.

Thanks,
Andreas

On Tue, Aug 5, 2025, at 11:25, Thomas Huth wrote:
>
> Since there does not seem to be any compelling reason anymore to use
> "-ansi" nowadays, let's simply drop the "-ansi" flag from the sparc
> subsystem now to get rid of those disadvantages.
>
> Signed-off-by: Thomas Huth <thuth@redhat.com>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>