* [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
@ 2021-04-22 9:27 Alexey Kardashevskiy
2021-04-22 22:58 ` Daniel Axtens
0 siblings, 1 reply; 6+ messages in thread
From: Alexey Kardashevskiy @ 2021-04-22 9:27 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Alexey Kardashevskiy
The $(CPP) (do only preprocessing) macro is already defined in Makefile.
However POWERPC redefines it and adds $(KBUILD_CFLAGS) which results
in flags duplication. Which is not a big deal by itself except for
the flags which depend on other flags and the compiler checks them
as it parses the command line.
Specifically, scripts/Makefile.build:304 generates ksyms for .S files.
If clang+llvm+sanitizer are enabled, this results in
-fno-lto -flto -fsanitize=cfi-mfcall .... -fno-lto -flto -fsanitize=cfi-mfcall
in the clang command line and triggers error:
clang-13: error: invalid argument '-fsanitize=cfi-mfcall' only allowed with '-flto'
This removes unnecessary CPP redifinition.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
arch/powerpc/Makefile | 1 -
1 file changed, 1 deletion(-)
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index c9d2c7825cd6..3a2f2001c62b 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -214,7 +214,6 @@ KBUILD_CPPFLAGS += -I $(srctree)/arch/$(ARCH) $(asinstr)
KBUILD_AFLAGS += $(AFLAGS-y)
KBUILD_CFLAGS += $(call cc-option,-msoft-float)
KBUILD_CFLAGS += -pipe $(CFLAGS-y)
-CPP = $(CC) -E $(KBUILD_CFLAGS)
CHECKFLAGS += -m$(BITS) -D__powerpc__ -D__powerpc$(BITS)__
ifdef CONFIG_CPU_BIG_ENDIAN
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
2021-04-22 9:27 [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor Alexey Kardashevskiy
@ 2021-04-22 22:58 ` Daniel Axtens
2021-04-23 3:06 ` Alexey Kardashevskiy
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Daniel Axtens @ 2021-04-22 22:58 UTC (permalink / raw)
To: Alexey Kardashevskiy, linuxppc-dev; +Cc: Alexey Kardashevskiy
Hi Alexey,
> The $(CPP) (do only preprocessing) macro is already defined in Makefile.
> However POWERPC redefines it and adds $(KBUILD_CFLAGS) which results
> in flags duplication. Which is not a big deal by itself except for
> the flags which depend on other flags and the compiler checks them
> as it parses the command line.
>
> Specifically, scripts/Makefile.build:304 generates ksyms for .S files.
> If clang+llvm+sanitizer are enabled, this results in
> -fno-lto -flto -fsanitize=cfi-mfcall .... -fno-lto -flto -fsanitize=cfi-mfcall
Checkpatch doesn't like this line:
WARNING:COMMIT_LOG_LONG_LINE: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#14:
-fno-lto -flto -fsanitize=cfi-mfcall .... -fno-lto -flto -fsanitize=cfi-mfcall
However, it doesn't make sense to wrap the line so we should just ignore
checkpatch here.
> in the clang command line and triggers error:
>
> clang-13: error: invalid argument '-fsanitize=cfi-mfcall' only allowed with '-flto'
>
> This removes unnecessary CPP redifinition.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> arch/powerpc/Makefile | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index c9d2c7825cd6..3a2f2001c62b 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -214,7 +214,6 @@ KBUILD_CPPFLAGS += -I $(srctree)/arch/$(ARCH) $(asinstr)
> KBUILD_AFLAGS += $(AFLAGS-y)
> KBUILD_CFLAGS += $(call cc-option,-msoft-float)
> KBUILD_CFLAGS += -pipe $(CFLAGS-y)
> -CPP = $(CC) -E $(KBUILD_CFLAGS)
I was trying to check the history to see why powerpc has its own
definition. It seems to date back at least as far as merging the two
powerpc platforms into one, maybe it was helpful then. I agree it
doesn't seem to be needed now.
Snowpatch claims that this breaks the build, but I haven't been able to
reproduce the issue in either pmac32 or ppc64 defconfig. I have sent it
off to a fork of mpe's linux-ci repo to see if any of those builds hit
any issues: https://github.com/daxtens/linux-ci/actions
Assuming that doesn't break, this patch looks good to me:
Reviewed-by: Daniel Axtens <dja@axtens.net>
Kind regards,
Daniel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
2021-04-22 22:58 ` Daniel Axtens
@ 2021-04-23 3:06 ` Alexey Kardashevskiy
2021-04-23 5:27 ` Christophe Leroy
2021-04-29 10:47 ` Michael Ellerman
2 siblings, 0 replies; 6+ messages in thread
From: Alexey Kardashevskiy @ 2021-04-23 3:06 UTC (permalink / raw)
To: Daniel Axtens, linuxppc-dev
On 23/04/2021 08:58, Daniel Axtens wrote:
> Hi Alexey,
>
>> The $(CPP) (do only preprocessing) macro is already defined in Makefile.
>> However POWERPC redefines it and adds $(KBUILD_CFLAGS) which results
>> in flags duplication. Which is not a big deal by itself except for
>> the flags which depend on other flags and the compiler checks them
>> as it parses the command line.
>>
>> Specifically, scripts/Makefile.build:304 generates ksyms for .S files.
>> If clang+llvm+sanitizer are enabled, this results in
>> -fno-lto -flto -fsanitize=cfi-mfcall .... -fno-lto -flto -fsanitize=cfi-mfcall
>
> Checkpatch doesn't like this line:
> WARNING:COMMIT_LOG_LONG_LINE: Possible unwrapped commit description (prefer a maximum 75 chars per line)
> #14:
> -fno-lto -flto -fsanitize=cfi-mfcall .... -fno-lto -flto -fsanitize=cfi-mfcall
> However, it doesn't make sense to wrap the line so we should just ignore
> checkpatch here.
>
>> in the clang command line and triggers error:
>>
>> clang-13: error: invalid argument '-fsanitize=cfi-mfcall' only allowed with '-flto'
>>
>> This removes unnecessary CPP redifinition.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>> arch/powerpc/Makefile | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
>> index c9d2c7825cd6..3a2f2001c62b 100644
>> --- a/arch/powerpc/Makefile
>> +++ b/arch/powerpc/Makefile
>> @@ -214,7 +214,6 @@ KBUILD_CPPFLAGS += -I $(srctree)/arch/$(ARCH) $(asinstr)
>> KBUILD_AFLAGS += $(AFLAGS-y)
>> KBUILD_CFLAGS += $(call cc-option,-msoft-float)
>> KBUILD_CFLAGS += -pipe $(CFLAGS-y)
>> -CPP = $(CC) -E $(KBUILD_CFLAGS)
>
> I was trying to check the history to see why powerpc has its own
> definition. It seems to date back at least as far as merging the two
> powerpc platforms into one, maybe it was helpful then. I agree it
> doesn't seem to be needed now.
>
> Snowpatch claims that this breaks the build, but I haven't been able to
> reproduce the issue in either pmac32 or ppc64 defconfig. I have sent it
> off to a fork of mpe's linux-ci repo to see if any of those builds hit
> any issues: https://github.com/daxtens/linux-ci/actions
To be precise, you need LLVM + LTO + byte code (-emit-llvm-bc), I am not
even sure what is the point of having -flto without -emit-llvm-bc.
No flags duplication:
[fstn1-p1 1]$ /mnt/sdb/pbuild/llvm-no-lto/bin/clang-13 -emit-llvm-bc
-fno-lto -flto -fvisibility=hidden -fsanitize=cfi-mfcall
/mnt/sdb/pbuild/llvm-bugs/1/a.c
/usr/bin/ld: warning: cannot find entry symbol mit-llvm-bc; defaulting
to 00000000100003e0
/usr/bin/ld:
/usr/lib/powerpc64le-linux-gnu/crt1.o:(.data.rel.ro.local+0x8):
undefined reference to `main'
clang-13: error: linker command failed with exit code 1 (use -v to see
invocation)
=> command line is fine, the file is not (but it is for debugging this
problem).
Now I am adding the second -fno-lto:
[fstn1-p1 1]$ /mnt/sdb/pbuild/llvm-no-lto/bin/clang-13 -emit-llvm-bc
-fno-lto -flto -fvisibility=hidden -fsanitize=cfi-mfcall -fno-lto
/mnt/sdb/pbuild/llvm-bugs/1/a.c
clang-13: error: invalid argument '-fsanitize=cfi-mfcall' only allowed
with '-flto'
=> failed.
> Assuming that doesn't break, this patch looks good to me:
> Reviewed-by: Daniel Axtens <dja@axtens.net>
>
> Kind regards,
> Daniel
>
--
Alexey
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
2021-04-22 22:58 ` Daniel Axtens
2021-04-23 3:06 ` Alexey Kardashevskiy
@ 2021-04-23 5:27 ` Christophe Leroy
2021-04-23 13:41 ` Michael Ellerman
2021-04-29 10:47 ` Michael Ellerman
2 siblings, 1 reply; 6+ messages in thread
From: Christophe Leroy @ 2021-04-23 5:27 UTC (permalink / raw)
To: Daniel Axtens, Alexey Kardashevskiy, linuxppc-dev
Le 23/04/2021 à 00:58, Daniel Axtens a écrit :
>> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
>> index c9d2c7825cd6..3a2f2001c62b 100644
>> --- a/arch/powerpc/Makefile
>> +++ b/arch/powerpc/Makefile
>> @@ -214,7 +214,6 @@ KBUILD_CPPFLAGS += -I $(srctree)/arch/$(ARCH) $(asinstr)
>> KBUILD_AFLAGS += $(AFLAGS-y)
>> KBUILD_CFLAGS += $(call cc-option,-msoft-float)
>> KBUILD_CFLAGS += -pipe $(CFLAGS-y)
>> -CPP = $(CC) -E $(KBUILD_CFLAGS)
>
> I was trying to check the history to see why powerpc has its own
> definition. It seems to date back at least as far as merging the two
> powerpc platforms into one, maybe it was helpful then. I agree it
> doesn't seem to be needed now.
>
I digged a bit deaper. It has been there since the introduction of arch/ppc/ in Linux 1.3.45
At the time, there was the exact same CPP definition in arch/mips/Makefile
The CPP definition in mips disappeared is Linux 2.1.44pre3.
Since that version, ppc has been the only one with such CPP re-definition.
> Snowpatch claims that this breaks the build, but I haven't been able to
> reproduce the issue in either pmac32 or ppc64 defconfig. I have sent it
> off to a fork of mpe's linux-ci repo to see if any of those builds hit
> any issues: https://github.com/daxtens/linux-ci/actions
>
By the way, I find snowpatch quite useless these days. It seems to delete the reports a few minutes
after the test. We are less than one day after the patch was submitted and the report of the build
failures are already gone.
Christophe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
2021-04-23 5:27 ` Christophe Leroy
@ 2021-04-23 13:41 ` Michael Ellerman
0 siblings, 0 replies; 6+ messages in thread
From: Michael Ellerman @ 2021-04-23 13:41 UTC (permalink / raw)
To: Christophe Leroy, Daniel Axtens, Alexey Kardashevskiy, linuxppc-dev
Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> Le 23/04/2021 à 00:58, Daniel Axtens a écrit :
>>> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
>>> index c9d2c7825cd6..3a2f2001c62b 100644
>>> --- a/arch/powerpc/Makefile
>>> +++ b/arch/powerpc/Makefile
>>> @@ -214,7 +214,6 @@ KBUILD_CPPFLAGS += -I $(srctree)/arch/$(ARCH) $(asinstr)
>>> KBUILD_AFLAGS += $(AFLAGS-y)
>>> KBUILD_CFLAGS += $(call cc-option,-msoft-float)
>>> KBUILD_CFLAGS += -pipe $(CFLAGS-y)
>>> -CPP = $(CC) -E $(KBUILD_CFLAGS)
>>
>> I was trying to check the history to see why powerpc has its own
>> definition. It seems to date back at least as far as merging the two
>> powerpc platforms into one, maybe it was helpful then. I agree it
>> doesn't seem to be needed now.
>>
>
> I digged a bit deaper. It has been there since the introduction of arch/ppc/ in Linux 1.3.45
> At the time, there was the exact same CPP definition in arch/mips/Makefile
>
> The CPP definition in mips disappeared is Linux 2.1.44pre3.
> Since that version, ppc has been the only one with such CPP re-definition.
>
>> Snowpatch claims that this breaks the build, but I haven't been able to
>> reproduce the issue in either pmac32 or ppc64 defconfig. I have sent it
>> off to a fork of mpe's linux-ci repo to see if any of those builds hit
>> any issues: https://github.com/daxtens/linux-ci/actions
>>
>
> By the way, I find snowpatch quite useless these days. It seems to delete the reports a few minutes
> after the test. We are less than one day after the patch was submitted and the report of the build
> failures are already gone.
Yeah, it's pretty annoying. It needs to send emails to the list with its
results, with a link to a location that retains the logs for some
reasonable period.
cheers
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
2021-04-22 22:58 ` Daniel Axtens
2021-04-23 3:06 ` Alexey Kardashevskiy
2021-04-23 5:27 ` Christophe Leroy
@ 2021-04-29 10:47 ` Michael Ellerman
2 siblings, 0 replies; 6+ messages in thread
From: Michael Ellerman @ 2021-04-29 10:47 UTC (permalink / raw)
To: Daniel Axtens, Alexey Kardashevskiy, linuxppc-dev; +Cc: Alexey Kardashevskiy
Daniel Axtens <dja@axtens.net> writes:
> Hi Alexey,
>
>> The $(CPP) (do only preprocessing) macro is already defined in Makefile.
>> However POWERPC redefines it and adds $(KBUILD_CFLAGS) which results
>> in flags duplication. Which is not a big deal by itself except for
>> the flags which depend on other flags and the compiler checks them
>> as it parses the command line.
>>
>> Specifically, scripts/Makefile.build:304 generates ksyms for .S files.
>> If clang+llvm+sanitizer are enabled, this results in
>> -fno-lto -flto -fsanitize=cfi-mfcall .... -fno-lto -flto -fsanitize=cfi-mfcall
>
> Checkpatch doesn't like this line:
> WARNING:COMMIT_LOG_LONG_LINE: Possible unwrapped commit description (prefer a maximum 75 chars per line)
> #14:
> -fno-lto -flto -fsanitize=cfi-mfcall .... -fno-lto -flto -fsanitize=cfi-mfcall
> However, it doesn't make sense to wrap the line so we should just ignore
> checkpatch here.
>
>> in the clang command line and triggers error:
>>
>> clang-13: error: invalid argument '-fsanitize=cfi-mfcall' only allowed with '-flto'
>>
>> This removes unnecessary CPP redifinition.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>> arch/powerpc/Makefile | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
>> index c9d2c7825cd6..3a2f2001c62b 100644
>> --- a/arch/powerpc/Makefile
>> +++ b/arch/powerpc/Makefile
>> @@ -214,7 +214,6 @@ KBUILD_CPPFLAGS += -I $(srctree)/arch/$(ARCH) $(asinstr)
>> KBUILD_AFLAGS += $(AFLAGS-y)
>> KBUILD_CFLAGS += $(call cc-option,-msoft-float)
>> KBUILD_CFLAGS += -pipe $(CFLAGS-y)
>> -CPP = $(CC) -E $(KBUILD_CFLAGS)
>
> I was trying to check the history to see why powerpc has its own
> definition. It seems to date back at least as far as merging the two
> powerpc platforms into one, maybe it was helpful then. I agree it
> doesn't seem to be needed now.
>
> Snowpatch claims that this breaks the build, but I haven't been able to
> reproduce the issue in either pmac32 or ppc64 defconfig. I have sent it
> off to a fork of mpe's linux-ci repo to see if any of those builds hit
> any issues: https://github.com/daxtens/linux-ci/actions
It does break the build.
cheers
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-04-29 10:47 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-22 9:27 [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor Alexey Kardashevskiy
2021-04-22 22:58 ` Daniel Axtens
2021-04-23 3:06 ` Alexey Kardashevskiy
2021-04-23 5:27 ` Christophe Leroy
2021-04-23 13:41 ` Michael Ellerman
2021-04-29 10:47 ` Michael Ellerman
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