Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
Daniel Axtens 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 >> --- >> 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
Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
Christophe Leroy 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
Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
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
Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
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 --- 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 13e0 /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 Kind regards, Daniel -- Alexey
Re: [PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
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 > --- > 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 Kind regards, Daniel
[PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor
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 --- 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
