On Sat, Jul 13, 2019 at 11:46 AM Masahiro Yamada
<yamada.masahiro@xxxxxxxxxxxxx> wrote:
>
> The assembler files in the kernel are *.S instead of *.s, so they must
> be preprocessed. Since 'as' of GNU binutils is not able to preprocess,
> we always use $(CC) as an assembler driver.
>
> $(AS) is almost unused in Kbuild. As of v5.2, there is just one place
> that directly invokes $(AS).
>
> $ git grep -e '$(AS)' -e '${AS}' -e '$AS' -e '$(AS:' -e '${AS:' -- :^Documentation
> drivers/net/wan/Makefile: AS68K = $(AS)
>
> The documentation about *_AFLAGS* sounds like the flags were passed
> to $(AS). This is somewhat misleading.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
> ---
Applied to linux-kbuild.
> Changes in v3:
> - Rebase
>
> Changes in v2:
> - Rephrase without using "assembling"
>
> Documentation/kbuild/kbuild.rst | 5 ++---
> Documentation/kbuild/makefiles.rst | 12 ++++++------
> 2 files changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst
> index b25548963d70..727520b3d7b1 100644
> --- a/Documentation/kbuild/kbuild.rst
> +++ b/Documentation/kbuild/kbuild.rst
> @@ -38,12 +38,11 @@ Additional options to the assembler (for built-in and modules).
>
> AFLAGS_MODULE
> -------------
> -Additional module specific options to use for $(AS).
> +Additional assembler options for modules.
>
> AFLAGS_KERNEL
> -------------
> -Additional options for $(AS) when used for assembler
> -code for code that is compiled as built-in.
> +Additional assembler options for built-in.
>
> KCFLAGS
> -------
> diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
> index 093f2d79ab95..67e47589d9d2 100644
> --- a/Documentation/kbuild/makefiles.rst
> +++ b/Documentation/kbuild/makefiles.rst
> @@ -328,7 +328,7 @@ more details, with real examples.
> variable $(KBUILD_CFLAGS) and uses it for compilation flags for the
> entire tree.
>
> - asflags-y specifies options for assembling with $(AS).
> + asflags-y specifies assembler options.
>
> Example::
>
> @@ -489,7 +489,7 @@ more details, with real examples.
> as-instr checks if the assembler reports a specific instruction
> and then outputs either option1 or option2
> C escapes are supported in the test instruction
> - Note: as-instr-option uses KBUILD_AFLAGS for $(AS) options
> + Note: as-instr-option uses KBUILD_AFLAGS for assembler options
>
> cc-option
> cc-option is used to check if $(CC) supports a given option, and if
> @@ -905,7 +905,7 @@ When kbuild executes, the following steps are followed (roughly):
> vmlinux. The usage of $(call if_changed,xxx) will be described later.
>
> KBUILD_AFLAGS
> - $(AS) assembler flags
> + Assembler flags
>
> Default value - see top level Makefile
> Append or modify as required per architecture.
> @@ -948,16 +948,16 @@ When kbuild executes, the following steps are followed (roughly):
> to 'y' when selected.
>
> KBUILD_AFLAGS_KERNEL
> - $(AS) options specific for built-in
> + Assembler options specific for built-in
>
> $(KBUILD_AFLAGS_KERNEL) contains extra C compiler flags used to compile
> resident kernel code.
>
> KBUILD_AFLAGS_MODULE
> - Options for $(AS) when building modules
> + Assembler options specific for modules
>
> $(KBUILD_AFLAGS_MODULE) is used to add arch-specific options that
> - are used for $(AS).
> + are used for assembler.
>
> From commandline AFLAGS_MODULE shall be used (see kbuild.txt).
>
> --
> 2.17.1
>
--
Best Regards
Masahiro Yamada
