diff mbox series

powerpc/Makefile: Allow overriding CPP

Message ID 20241107112646.32401-1-mpe@ellerman.id.au (mailing list archive)
State Accepted
Commit a5371018eefdd81f4152926a6d2b9480a75ac2a6
Headers show
Series powerpc/Makefile: Allow overriding CPP | expand

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Commit Message

Michael Ellerman Nov. 7, 2024, 11:26 a.m. UTC 
From: Arnd Bergmann <arnd@arndb.de>

Unlike all other arches, powerpc doesn't allow the user to override CPP,
because it sets it unconditionally in the arch Makefile. This can lead
to strange build failures.

Instead add the required flags to KBUILD_CPPFLAGS, which are passed
to CPP, CC and AS invocations by the generic Makefile logic.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Closes: https://lore.kernel.org/all/20240607061629.530301-1-arnd@kernel.org
[mpe: Rebase, write change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/Makefile             | 7 +++----
 arch/powerpc/kernel/vdso/Makefile | 2 +-
 2 files changed, 4 insertions(+), 5 deletions(-)

Comments

Nathan Chancellor Nov. 7, 2024, 5:52 p.m. UTC | #1 
On Thu, Nov 07, 2024 at 10:26:46PM +1100, Michael Ellerman wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> Unlike all other arches, powerpc doesn't allow the user to override CPP,
> because it sets it unconditionally in the arch Makefile. This can lead
> to strange build failures.
> 
> Instead add the required flags to KBUILD_CPPFLAGS, which are passed
> to CPP, CC and AS invocations by the generic Makefile logic.
> 
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> Closes: https://lore.kernel.org/all/20240607061629.530301-1-arnd@kernel.org
> [mpe: Rebase, write change log]
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

My builds are still green with this change applied.

Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>

> ---
>  arch/powerpc/Makefile             | 7 +++----
>  arch/powerpc/kernel/vdso/Makefile | 2 +-
>  2 files changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index cbb353ddacb7..94a6ccb8ad12 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -62,14 +62,14 @@ KBUILD_LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o
>  endif
>  
>  ifdef CONFIG_CPU_LITTLE_ENDIAN
> -KBUILD_CFLAGS	+= -mlittle-endian
> +KBUILD_CPPFLAGS	+= -mlittle-endian
>  KBUILD_LDFLAGS	+= -EL
>  LDEMULATION	:= lppc
>  GNUTARGET	:= powerpcle
>  MULTIPLEWORD	:= -mno-multiple
>  KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-save-toc-indirect)
>  else
> -KBUILD_CFLAGS += $(call cc-option,-mbig-endian)
> +KBUILD_CPPFLAGS	+= $(call cc-option,-mbig-endian)
>  KBUILD_LDFLAGS	+= -EB
>  LDEMULATION	:= ppc
>  GNUTARGET	:= powerpc
> @@ -95,7 +95,7 @@ aflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mbig-endian)
>  aflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mlittle-endian
>  
>  ifeq ($(HAS_BIARCH),y)
> -KBUILD_CFLAGS	+= -m$(BITS)
> +KBUILD_CPPFLAGS	+= -m$(BITS)
>  KBUILD_AFLAGS	+= -m$(BITS)
>  KBUILD_LDFLAGS	+= -m elf$(BITS)$(LDEMULATION)
>  endif
> @@ -168,7 +168,6 @@ KBUILD_CPPFLAGS	+= -I $(srctree)/arch/powerpc $(asinstr)
>  KBUILD_AFLAGS	+= $(AFLAGS-y)
>  KBUILD_CFLAGS	+= $(CC_FLAGS_NO_FPU)
>  KBUILD_CFLAGS	+= $(CFLAGS-y)
> -CPP		= $(CC) -E $(KBUILD_CFLAGS)
>  
>  CHECKFLAGS	+= -m$(BITS) -D__powerpc__ -D__powerpc$(BITS)__
>  ifdef CONFIG_CPU_BIG_ENDIAN
> diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
> index 31ca5a547004..af130c82a71a 100644
> --- a/arch/powerpc/kernel/vdso/Makefile
> +++ b/arch/powerpc/kernel/vdso/Makefile
> @@ -50,7 +50,7 @@ ldflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
>  ldflags-$(CONFIG_LD_ORPHAN_WARN) += -Wl,--orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
>  
>  # Filter flags that clang will warn are unused for linking
> -ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CFLAGS))
> +ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
>  
>  CC32FLAGS := -m32
>  CC32FLAGSREMOVE := -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc
> -- 
> 2.47.0
>
Segher Boessenkool Nov. 7, 2024, 7:14 p.m. UTC | #2 
On Thu, Nov 07, 2024 at 10:26:46PM +1100, Michael Ellerman wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> Unlike all other arches, powerpc doesn't allow the user to override CPP,
> because it sets it unconditionally in the arch Makefile. This can lead
> to strange build failures.
> 
> Instead add the required flags to KBUILD_CPPFLAGS, which are passed
> to CPP, CC and AS invocations by the generic Makefile logic.

You can also use "CPP ?=" instead of "CPP =".  Your solution is better
I think, but, FYI, FFR :-)


Segher
Michael Ellerman Nov. 17, 2024, 12:09 p.m. UTC | #3 
On Thu, 07 Nov 2024 22:26:46 +1100, Michael Ellerman wrote:
> Unlike all other arches, powerpc doesn't allow the user to override CPP,
> because it sets it unconditionally in the arch Makefile. This can lead
> to strange build failures.
> 
> Instead add the required flags to KBUILD_CPPFLAGS, which are passed
> to CPP, CC and AS invocations by the generic Makefile logic.
> 
> [...]

Applied to powerpc/next.

[1/1] powerpc/Makefile: Allow overriding CPP
      https://git.kernel.org/powerpc/c/a5371018eefdd81f4152926a6d2b9480a75ac2a6

cheers
diff mbox series

Patch

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index cbb353ddacb7..94a6ccb8ad12 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -62,14 +62,14 @@  KBUILD_LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o
 endif
 
 ifdef CONFIG_CPU_LITTLE_ENDIAN
-KBUILD_CFLAGS	+= -mlittle-endian
+KBUILD_CPPFLAGS	+= -mlittle-endian
 KBUILD_LDFLAGS	+= -EL
 LDEMULATION	:= lppc
 GNUTARGET	:= powerpcle
 MULTIPLEWORD	:= -mno-multiple
 KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-save-toc-indirect)
 else
-KBUILD_CFLAGS += $(call cc-option,-mbig-endian)
+KBUILD_CPPFLAGS	+= $(call cc-option,-mbig-endian)
 KBUILD_LDFLAGS	+= -EB
 LDEMULATION	:= ppc
 GNUTARGET	:= powerpc
@@ -95,7 +95,7 @@  aflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mbig-endian)
 aflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mlittle-endian
 
 ifeq ($(HAS_BIARCH),y)
-KBUILD_CFLAGS	+= -m$(BITS)
+KBUILD_CPPFLAGS	+= -m$(BITS)
 KBUILD_AFLAGS	+= -m$(BITS)
 KBUILD_LDFLAGS	+= -m elf$(BITS)$(LDEMULATION)
 endif
@@ -168,7 +168,6 @@  KBUILD_CPPFLAGS	+= -I $(srctree)/arch/powerpc $(asinstr)
 KBUILD_AFLAGS	+= $(AFLAGS-y)
 KBUILD_CFLAGS	+= $(CC_FLAGS_NO_FPU)
 KBUILD_CFLAGS	+= $(CFLAGS-y)
-CPP		= $(CC) -E $(KBUILD_CFLAGS)
 
 CHECKFLAGS	+= -m$(BITS) -D__powerpc__ -D__powerpc$(BITS)__
 ifdef CONFIG_CPU_BIG_ENDIAN
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index 31ca5a547004..af130c82a71a 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -50,7 +50,7 @@  ldflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
 ldflags-$(CONFIG_LD_ORPHAN_WARN) += -Wl,--orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
 
 # Filter flags that clang will warn are unused for linking
-ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CFLAGS))
+ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
 
 CC32FLAGS := -m32
 CC32FLAGSREMOVE := -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc