* [PATCH v2] kbuild: get rid of misleading $(AS) from documents
@ 2019-07-06 16:25 Masahiro Yamada
2019-07-08 20:02 ` Jonathan Corbet
0 siblings, 1 reply; 3+ messages in thread
From: Masahiro Yamada @ 2019-07-06 16:25 UTC (permalink / raw)
To: linux-kbuild
Cc: Sam Ravnborg, Masahiro Yamada, linux-doc, linux-kernel,
Jonathan Corbet, Michal Marek
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 writing, 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 v2:
- Rephrase without using "assembling"
Documentation/kbuild/kbuild.txt | 5 ++---
Documentation/kbuild/makefiles.txt | 12 ++++++------
2 files changed, 8 insertions(+), 9 deletions(-)
diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt
index 9c230ea71963..2c6188abb213 100644
--- a/Documentation/kbuild/kbuild.txt
+++ b/Documentation/kbuild/kbuild.txt
@@ -31,12 +31,11 @@ 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.txt b/Documentation/kbuild/makefiles.txt
index d65ad5746f94..895bbbf38a0c 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -306,7 +306,7 @@ 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:
#arch/sparc/kernel/Makefile
@@ -441,7 +441,7 @@ 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
@@ -814,7 +814,7 @@ When kbuild executes, the following steps are followed (roughly):
In this example, the binary $(obj)/image is a binary version of
vmlinux. The usage of $(call if_changed,xxx) will be described later.
- KBUILD_AFLAGS $(AS) assembler flags
+ KBUILD_AFLAGS assembler flags
Default value - see top level Makefile
Append or modify as required per architecture.
@@ -853,15 +853,15 @@ When kbuild executes, the following steps are followed (roughly):
The first example utilises the trick that a config option expands
to 'y' when selected.
- KBUILD_AFLAGS_KERNEL $(AS) options specific for built-in
+ KBUILD_AFLAGS_KERNEL 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
+ KBUILD_AFLAGS_MODULE 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).
KBUILD_CFLAGS_KERNEL $(CC) options specific for built-in
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] kbuild: get rid of misleading $(AS) from documents
2019-07-06 16:25 [PATCH v2] kbuild: get rid of misleading $(AS) from documents Masahiro Yamada
@ 2019-07-08 20:02 ` Jonathan Corbet
2019-07-09 1:06 ` Masahiro Yamada
0 siblings, 1 reply; 3+ messages in thread
From: Jonathan Corbet @ 2019-07-08 20:02 UTC (permalink / raw)
To: Masahiro Yamada
Cc: linux-kbuild, Sam Ravnborg, linux-doc, linux-kernel, Michal Marek
On Sun, 7 Jul 2019 01:25:08 +0900
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 writing, 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>
Would you like me to send this up through the docs tree?
Thanks,
jon
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] kbuild: get rid of misleading $(AS) from documents
2019-07-08 20:02 ` Jonathan Corbet
@ 2019-07-09 1:06 ` Masahiro Yamada
0 siblings, 0 replies; 3+ messages in thread
From: Masahiro Yamada @ 2019-07-09 1:06 UTC (permalink / raw)
To: Jonathan Corbet
Cc: Linux Kbuild mailing list, Sam Ravnborg, open list:DOCUMENTATION,
Linux Kernel Mailing List, Michal Marek
On Tue, Jul 9, 2019 at 5:02 AM Jonathan Corbet <corbet@lwn.net> wrote:
>
> On Sun, 7 Jul 2019 01:25:08 +0900
> 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 writing, 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>
>
> Would you like me to send this up through the docs tree?
No, I will apply it to linux-kbuild shortly.
Thanks.
--
Best Regards
Masahiro Yamada
^ permalink raw reply [flat|nested] 3+ messages in thread
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