| Message ID | 20190713024558.27214-1-yamada.masahiro@socionext.com |
|---|---|
| State | Accepted |
| Commit | 5ef872636ca71d35ddc5ee5951c9272a51c74418 |
| Headers | show |
| Series | [v3] kbuild: get rid of misleading $(AS) from documents | expand |
On Sat, Jul 13, 2019 at 11:46 AM Masahiro Yamada <yamada.masahiro@socionext.com> 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@socionext.com> > Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- 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
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).
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@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> --- 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(-) -- 2.17.1