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* [PATCH] x86/build: remove stale cc-option checks
@ 2021-08-11 17:56 Nick Desaulniers
  2021-08-11 19:22 ` Nathan Chancellor
  0 siblings, 1 reply; 3+ messages in thread
From: Nick Desaulniers @ 2021-08-11 17:56 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, Borislav Petkov
  Cc: Masahiro Yamada, Nick Desaulniers, x86, H. Peter Anvin,
	Nathan Chancellor, linux-kernel, clang-built-linux

cc-option, __cc-option, cc-option-yn, and cc-disable-warning all invoke
the compiler during build time, and can slow down the build when these
checks become stale for our supported compilers, whose minimally
supported versions increases over time. See
Documentation/process/changes.rst for the current supported minimal
versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these
flags may be verified on godbolt.org.

The following flags are supported by all supported versions of GCC and
Clang. Remove their cc-option, __cc-option, and cc-option-yn tests.
* -Wno-address-of-packed-member
* -mno-avx
* -m32
* -mno-80387
* -march=k8
* -march=nocona
* -march=core2
* -march=atom
* -mtune=generic
* -mfentry

-mpreferred-stack-boundary= is specific to GCC, while
-mstack-alignment= is specific to Clang. Rather than test for this three
times via cc-option and __cc-option, rely on CONFIG_CC_IS_* from
Kconfig.

Link: https://github.com/ClangBuiltLinux/linux/issues/1436
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
 arch/x86/Makefile | 51 +++++++++++++++++------------------------------
 1 file changed, 18 insertions(+), 33 deletions(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 0fa7dc73b5d8..6de2985ba1a5 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -14,10 +14,13 @@ endif
 
 # For gcc stack alignment is specified with -mpreferred-stack-boundary,
 # clang has the option -mstack-alignment for that purpose.
+ifdef CONFIG_CC_IS_GCC
 ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
       cc_stack_align4 := -mpreferred-stack-boundary=2
       cc_stack_align8 := -mpreferred-stack-boundary=3
-else ifneq ($(call cc-option, -mstack-alignment=16),)
+endif
+endif
+ifdef CONFIG_CC_IS_CLANG
       cc_stack_align4 := -mstack-alignment=4
       cc_stack_align8 := -mstack-alignment=8
 endif
@@ -31,8 +34,8 @@ REALMODE_CFLAGS	:= -m16 -g -Os -DDISABLE_BRANCH_PROFILING \
 
 REALMODE_CFLAGS += -ffreestanding
 REALMODE_CFLAGS += -fno-stack-protector
-REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
-REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
+REALMODE_CFLAGS += -Wno-address-of-packed-member
+REALMODE_CFLAGS += $(cc_stack_align4)
 REALMODE_CFLAGS += $(CLANG_FLAGS)
 export REALMODE_CFLAGS
 
@@ -48,8 +51,7 @@ export BITS
 #
 #    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
 #
-KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
-KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
+KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
 
 # Intel CET isn't enabled in the kernel
 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
@@ -59,9 +61,8 @@ ifeq ($(CONFIG_X86_32),y)
         UTS_MACHINE := i386
         CHECKFLAGS += -D__i386__
 
-        biarch := $(call cc-option,-m32)
-        KBUILD_AFLAGS += $(biarch)
-        KBUILD_CFLAGS += $(biarch)
+        KBUILD_AFLAGS += -m32
+        KBUILD_CFLAGS += -m32
 
         KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
 
@@ -72,7 +73,7 @@ ifeq ($(CONFIG_X86_32),y)
         # Align the stack to the register width instead of using the default
         # alignment of 16 bytes. This reduces stack usage and the number of
         # alignment instructions.
-        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
+        KBUILD_CFLAGS += $(cc_stack_align4)
 
         # CPU-specific tuning. Anything which can be shared with UML should go here.
         include $(srctree)/arch/x86/Makefile_32.cpu
@@ -93,7 +94,6 @@ else
         UTS_MACHINE := x86_64
         CHECKFLAGS += -D__x86_64__
 
-        biarch := -m64
         KBUILD_AFLAGS += -m64
         KBUILD_CFLAGS += -m64
 
@@ -104,7 +104,7 @@ else
         KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
 
         # Don't autogenerate traditional x87 instructions
-        KBUILD_CFLAGS += $(call cc-option,-mno-80387)
+        KBUILD_CFLAGS += -mno-80387
         KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
 
         # By default gcc and clang use a stack alignment of 16 bytes for x86.
@@ -114,20 +114,17 @@ else
         # default alignment which keep the stack *mis*aligned.
         # Furthermore an alignment to the register width reduces stack usage
         # and the number of alignment instructions.
-        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
+        KBUILD_CFLAGS += $(cc_stack_align8)
 
 	# Use -mskip-rax-setup if supported.
 	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
 
         # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
-        cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
-        cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
-
-        cflags-$(CONFIG_MCORE2) += \
-                $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
-	cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
-		$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
-        cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
+        cflags-$(CONFIG_MK8)		+= -march=k8
+        cflags-$(CONFIG_MPSC)		+= -march=nocona
+        cflags-$(CONFIG_MCORE2)		+= -march=core2
+        cflags-$(CONFIG_MATOM)		+= -march=atom
+        cflags-$(CONFIG_GENERIC_CPU)	+= -mtune=generic
         KBUILD_CFLAGS += $(cflags-y)
 
         KBUILD_CFLAGS += -mno-red-zone
@@ -158,18 +155,6 @@ export CONFIG_X86_X32_ABI
 ifdef CONFIG_FUNCTION_GRAPH_TRACER
   ifndef CONFIG_HAVE_FENTRY
 	ACCUMULATE_OUTGOING_ARGS := 1
-  else
-    ifeq ($(call cc-option-yn, -mfentry), n)
-	ACCUMULATE_OUTGOING_ARGS := 1
-
-	# GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
-	# If '-Os' is enabled, disable it and print a warning.
-        ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
-          undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
-          $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE.  Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
-        endif
-
-    endif
   endif
 endif
 
@@ -193,7 +178,7 @@ ifdef CONFIG_RETPOLINE
   # only been fixed starting from gcc stable version 8.4.0 and
   # onwards, but not for older ones. See gcc bug #86952.
   ifndef CONFIG_CC_IS_CLANG
-    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
+    KBUILD_CFLAGS += -fno-jump-tables
   endif
 endif
 
-- 
2.32.0.605.g8dce9f2422-goog


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] x86/build: remove stale cc-option checks
  2021-08-11 17:56 [PATCH] x86/build: remove stale cc-option checks Nick Desaulniers
@ 2021-08-11 19:22 ` Nathan Chancellor
  2021-08-11 20:08   ` Nick Desaulniers
  0 siblings, 1 reply; 3+ messages in thread
From: Nathan Chancellor @ 2021-08-11 19:22 UTC (permalink / raw)
  To: Nick Desaulniers, Thomas Gleixner, Ingo Molnar, Borislav Petkov
  Cc: Masahiro Yamada, x86, H. Peter Anvin, linux-kernel, clang-built-linux

On 8/11/2021 10:56 AM, Nick Desaulniers wrote:
> cc-option, __cc-option, cc-option-yn, and cc-disable-warning all invoke
> the compiler during build time, and can slow down the build when these
> checks become stale for our supported compilers, whose minimally
> supported versions increases over time. See
> Documentation/process/changes.rst for the current supported minimal
> versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these
> flags may be verified on godbolt.org.
> 
> The following flags are supported by all supported versions of GCC and
> Clang. Remove their cc-option, __cc-option, and cc-option-yn tests.
> * -Wno-address-of-packed-member
> * -mno-avx
> * -m32
> * -mno-80387
> * -march=k8
> * -march=nocona
> * -march=core2
> * -march=atom
> * -mtune=generic
> * -mfentry
> 
> -mpreferred-stack-boundary= is specific to GCC, while
> -mstack-alignment= is specific to Clang. Rather than test for this three
> times via cc-option and __cc-option, rely on CONFIG_CC_IS_* from
> Kconfig.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1436
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

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

A few comments below.

> ---
>   arch/x86/Makefile | 51 +++++++++++++++++------------------------------
>   1 file changed, 18 insertions(+), 33 deletions(-)
> 
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 0fa7dc73b5d8..6de2985ba1a5 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -14,10 +14,13 @@ endif
>   
>   # For gcc stack alignment is specified with -mpreferred-stack-boundary,
>   # clang has the option -mstack-alignment for that purpose.
> +ifdef CONFIG_CC_IS_GCC
>   ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)

Is this cc-option call still needed? It looks like it was added by 
commit d77698df39a5 ("x86/build: Specify stack alignment for clang"), 
which at the time claimed to support back to gcc 3.2, but that flag 
appears to be supported at least back to gcc 4.1.2 according to godbolt.

>         cc_stack_align4 := -mpreferred-stack-boundary=2
>         cc_stack_align8 := -mpreferred-stack-boundary=3
> -else ifneq ($(call cc-option, -mstack-alignment=16),)
> +endif
> +endif
> +ifdef CONFIG_CC_IS_CLANG
>         cc_stack_align4 := -mstack-alignment=4
>         cc_stack_align8 := -mstack-alignment=8
>   endif
> @@ -31,8 +34,8 @@ REALMODE_CFLAGS	:= -m16 -g -Os -DDISABLE_BRANCH_PROFILING \
>   
>   REALMODE_CFLAGS += -ffreestanding
>   REALMODE_CFLAGS += -fno-stack-protector
> -REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
> -REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
> +REALMODE_CFLAGS += -Wno-address-of-packed-member
> +REALMODE_CFLAGS += $(cc_stack_align4)
>   REALMODE_CFLAGS += $(CLANG_FLAGS)
>   export REALMODE_CFLAGS
>   
> @@ -48,8 +51,7 @@ export BITS
>   #
>   #    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
>   #
> -KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
> -KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
> +KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
>   
>   # Intel CET isn't enabled in the kernel
>   KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
> @@ -59,9 +61,8 @@ ifeq ($(CONFIG_X86_32),y)
>           UTS_MACHINE := i386
>           CHECKFLAGS += -D__i386__
>   
> -        biarch := $(call cc-option,-m32)
> -        KBUILD_AFLAGS += $(biarch)
> -        KBUILD_CFLAGS += $(biarch)
> +        KBUILD_AFLAGS += -m32
> +        KBUILD_CFLAGS += -m32
>   
>           KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
>   
> @@ -72,7 +73,7 @@ ifeq ($(CONFIG_X86_32),y)
>           # Align the stack to the register width instead of using the default
>           # alignment of 16 bytes. This reduces stack usage and the number of
>           # alignment instructions.
> -        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
> +        KBUILD_CFLAGS += $(cc_stack_align4)
>   
>           # CPU-specific tuning. Anything which can be shared with UML should go here.
>           include $(srctree)/arch/x86/Makefile_32.cpu

What tree were you intending to target with this? If it is -tip, this is 
going to cause it to fail to apply because the '$(srctree)' comes from 
Masahiro:

https://git.kernel.org/masahiroy/linux-kbuild/c/d8285639550578a1bf2d102391d1a9e08e0586ca

> @@ -93,7 +94,6 @@ else
>           UTS_MACHINE := x86_64
>           CHECKFLAGS += -D__x86_64__
>   
> -        biarch := -m64
>           KBUILD_AFLAGS += -m64
>           KBUILD_CFLAGS += -m64
>   
> @@ -104,7 +104,7 @@ else
>           KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
>   
>           # Don't autogenerate traditional x87 instructions
> -        KBUILD_CFLAGS += $(call cc-option,-mno-80387)
> +        KBUILD_CFLAGS += -mno-80387
>           KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
>   
>           # By default gcc and clang use a stack alignment of 16 bytes for x86.
> @@ -114,20 +114,17 @@ else
>           # default alignment which keep the stack *mis*aligned.
>           # Furthermore an alignment to the register width reduces stack usage
>           # and the number of alignment instructions.
> -        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
> +        KBUILD_CFLAGS += $(cc_stack_align8)
>   
>   	# Use -mskip-rax-setup if supported.
>   	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
>   
>           # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
> -        cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
> -        cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
> -
> -        cflags-$(CONFIG_MCORE2) += \
> -                $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
> -	cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
> -		$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
> -        cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
> +        cflags-$(CONFIG_MK8)		+= -march=k8
> +        cflags-$(CONFIG_MPSC)		+= -march=nocona
> +        cflags-$(CONFIG_MCORE2)		+= -march=core2
> +        cflags-$(CONFIG_MATOM)		+= -march=atom
> +        cflags-$(CONFIG_GENERIC_CPU)	+= -mtune=generic
>           KBUILD_CFLAGS += $(cflags-y)
>   
>           KBUILD_CFLAGS += -mno-red-zone
> @@ -158,18 +155,6 @@ export CONFIG_X86_X32_ABI
>   ifdef CONFIG_FUNCTION_GRAPH_TRACER
>     ifndef CONFIG_HAVE_FENTRY
>   	ACCUMULATE_OUTGOING_ARGS := 1
> -  else
> -    ifeq ($(call cc-option-yn, -mfentry), n)
> -	ACCUMULATE_OUTGOING_ARGS := 1
> -
> -	# GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
> -	# If '-Os' is enabled, disable it and print a warning.
> -        ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
> -          undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
> -          $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE.  Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
> -        endif
> -
> -    endif
>     endif
>   endif
>   
> @@ -193,7 +178,7 @@ ifdef CONFIG_RETPOLINE
>     # only been fixed starting from gcc stable version 8.4.0 and
>     # onwards, but not for older ones. See gcc bug #86952.
>     ifndef CONFIG_CC_IS_CLANG
> -    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
> +    KBUILD_CFLAGS += -fno-jump-tables
>     endif
>   endif
>   
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] x86/build: remove stale cc-option checks
  2021-08-11 19:22 ` Nathan Chancellor
@ 2021-08-11 20:08   ` Nick Desaulniers
  0 siblings, 0 replies; 3+ messages in thread
From: Nick Desaulniers @ 2021-08-11 20:08 UTC (permalink / raw)
  To: Nathan Chancellor
  Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Masahiro Yamada,
	x86, H. Peter Anvin, linux-kernel, clang-built-linux

On Wed, Aug 11, 2021 at 12:22 PM Nathan Chancellor <nathan@kernel.org> wrote:
>
> On 8/11/2021 10:56 AM, Nick Desaulniers wrote:
> > cc-option, __cc-option, cc-option-yn, and cc-disable-warning all invoke
> > the compiler during build time, and can slow down the build when these
> > checks become stale for our supported compilers, whose minimally
> > supported versions increases over time. See
> > Documentation/process/changes.rst for the current supported minimal
> > versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these
> > flags may be verified on godbolt.org.
> >
> > The following flags are supported by all supported versions of GCC and
> > Clang. Remove their cc-option, __cc-option, and cc-option-yn tests.
> > * -Wno-address-of-packed-member
> > * -mno-avx
> > * -m32
> > * -mno-80387
> > * -march=k8
> > * -march=nocona
> > * -march=core2
> > * -march=atom
> > * -mtune=generic
> > * -mfentry
> >
> > -mpreferred-stack-boundary= is specific to GCC, while
> > -mstack-alignment= is specific to Clang. Rather than test for this three
> > times via cc-option and __cc-option, rely on CONFIG_CC_IS_* from
> > Kconfig.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1436
> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
>
> Reviewed-by: Nathan Chancellor <nathan@kernel.org>
>
> A few comments below.
>
> > ---
> >   arch/x86/Makefile | 51 +++++++++++++++++------------------------------
> >   1 file changed, 18 insertions(+), 33 deletions(-)
> >
> > diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> > index 0fa7dc73b5d8..6de2985ba1a5 100644
> > --- a/arch/x86/Makefile
> > +++ b/arch/x86/Makefile
> > @@ -14,10 +14,13 @@ endif
> >
> >   # For gcc stack alignment is specified with -mpreferred-stack-boundary,
> >   # clang has the option -mstack-alignment for that purpose.
> > +ifdef CONFIG_CC_IS_GCC
> >   ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
>
> Is this cc-option call still needed? It looks like it was added by
> commit d77698df39a5 ("x86/build: Specify stack alignment for clang"),
> which at the time claimed to support back to gcc 3.2, but that flag
> appears to be supported at least back to gcc 4.1.2 according to godbolt.

Yes!
https://godbolt.org/z/1nWbrGTb3

While the test is for a value of 4, the actual flags used are 2 and 3;
values less than 4 were only supported in GCC 7+!
So the test is wrong and should have been for a value less than 4; it
didn't fail because of the additional cc-option/__cc-option below that
I removed.

So I should send a v2 that changes that particular test to test
support for the value 3 (or 2) rather than 4.  Let me know off thread
if you'd like me to carry forward your RB tag for that.

>
> >         cc_stack_align4 := -mpreferred-stack-boundary=2
> >         cc_stack_align8 := -mpreferred-stack-boundary=3
> > -else ifneq ($(call cc-option, -mstack-alignment=16),)
> > +endif
> > +endif
> > +ifdef CONFIG_CC_IS_CLANG
> >         cc_stack_align4 := -mstack-alignment=4
> >         cc_stack_align8 := -mstack-alignment=8
> >   endif
> > @@ -31,8 +34,8 @@ REALMODE_CFLAGS     := -m16 -g -Os -DDISABLE_BRANCH_PROFILING \
> >
> >   REALMODE_CFLAGS += -ffreestanding
> >   REALMODE_CFLAGS += -fno-stack-protector
> > -REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
> > -REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
> > +REALMODE_CFLAGS += -Wno-address-of-packed-member
> > +REALMODE_CFLAGS += $(cc_stack_align4)
> >   REALMODE_CFLAGS += $(CLANG_FLAGS)
> >   export REALMODE_CFLAGS
> >
> > @@ -48,8 +51,7 @@ export BITS
> >   #
> >   #    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
> >   #
> > -KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
> > -KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
> > +KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
> >
> >   # Intel CET isn't enabled in the kernel
> >   KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
> > @@ -59,9 +61,8 @@ ifeq ($(CONFIG_X86_32),y)
> >           UTS_MACHINE := i386
> >           CHECKFLAGS += -D__i386__
> >
> > -        biarch := $(call cc-option,-m32)
> > -        KBUILD_AFLAGS += $(biarch)
> > -        KBUILD_CFLAGS += $(biarch)
> > +        KBUILD_AFLAGS += -m32
> > +        KBUILD_CFLAGS += -m32
> >
> >           KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
> >
> > @@ -72,7 +73,7 @@ ifeq ($(CONFIG_X86_32),y)
> >           # Align the stack to the register width instead of using the default
> >           # alignment of 16 bytes. This reduces stack usage and the number of
> >           # alignment instructions.
> > -        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
> > +        KBUILD_CFLAGS += $(cc_stack_align4)
> >
> >           # CPU-specific tuning. Anything which can be shared with UML should go here.
> >           include $(srctree)/arch/x86/Makefile_32.cpu
>
> What tree were you intending to target with this? If it is -tip, this is
> going to cause it to fail to apply because the '$(srctree)' comes from
> Masahiro:
>
> https://git.kernel.org/masahiroy/linux-kbuild/c/d8285639550578a1bf2d102391d1a9e08e0586ca

I can regen v2 against tip.

>
> > @@ -93,7 +94,6 @@ else
> >           UTS_MACHINE := x86_64
> >           CHECKFLAGS += -D__x86_64__
> >
> > -        biarch := -m64
> >           KBUILD_AFLAGS += -m64
> >           KBUILD_CFLAGS += -m64
> >
> > @@ -104,7 +104,7 @@ else
> >           KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
> >
> >           # Don't autogenerate traditional x87 instructions
> > -        KBUILD_CFLAGS += $(call cc-option,-mno-80387)
> > +        KBUILD_CFLAGS += -mno-80387
> >           KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
> >
> >           # By default gcc and clang use a stack alignment of 16 bytes for x86.
> > @@ -114,20 +114,17 @@ else
> >           # default alignment which keep the stack *mis*aligned.
> >           # Furthermore an alignment to the register width reduces stack usage
> >           # and the number of alignment instructions.
> > -        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
> > +        KBUILD_CFLAGS += $(cc_stack_align8)
> >
> >       # Use -mskip-rax-setup if supported.
> >       KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
> >
> >           # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
> > -        cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
> > -        cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
> > -
> > -        cflags-$(CONFIG_MCORE2) += \
> > -                $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
> > -     cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
> > -             $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
> > -        cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
> > +        cflags-$(CONFIG_MK8)         += -march=k8
> > +        cflags-$(CONFIG_MPSC)                += -march=nocona
> > +        cflags-$(CONFIG_MCORE2)              += -march=core2
> > +        cflags-$(CONFIG_MATOM)               += -march=atom
> > +        cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic
> >           KBUILD_CFLAGS += $(cflags-y)
> >
> >           KBUILD_CFLAGS += -mno-red-zone
> > @@ -158,18 +155,6 @@ export CONFIG_X86_X32_ABI
> >   ifdef CONFIG_FUNCTION_GRAPH_TRACER
> >     ifndef CONFIG_HAVE_FENTRY
> >       ACCUMULATE_OUTGOING_ARGS := 1
> > -  else
> > -    ifeq ($(call cc-option-yn, -mfentry), n)
> > -     ACCUMULATE_OUTGOING_ARGS := 1
> > -
> > -     # GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
> > -     # If '-Os' is enabled, disable it and print a warning.
> > -        ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
> > -          undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
> > -          $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE.  Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
> > -        endif
> > -
> > -    endif
> >     endif
> >   endif
> >
> > @@ -193,7 +178,7 @@ ifdef CONFIG_RETPOLINE
> >     # only been fixed starting from gcc stable version 8.4.0 and
> >     # onwards, but not for older ones. See gcc bug #86952.
> >     ifndef CONFIG_CC_IS_CLANG
> > -    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
> > +    KBUILD_CFLAGS += -fno-jump-tables
> >     endif
> >   endif
> >
> >
>
> --

-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-08-11 20:09 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-11 17:56 [PATCH] x86/build: remove stale cc-option checks Nick Desaulniers
2021-08-11 19:22 ` Nathan Chancellor
2021-08-11 20:08   ` Nick Desaulniers

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