linux-next: build failure after merge of the tip tree

linux-next: build failure after merge of the tip tree

[Stephen Rothwell]

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Hi all,

After merging the tip tree, today's linux-next build (x86_64 allmodconfig)
failed like this:

cc1: error: bad value 'native' for '-march=' switch
cc1: note: valid arguments to '-march=' switch are: nocona core2 nehalem corei7 westmere sandybridge corei7-avx ivybridge core-avx-i haswell core-avx2 broadwell skylake skylake-avx512 cannonlake icelake-client rocketlake icelake-server cascadelake tigerlake cooperlake sapphirerapids emeraldrapids alderlake raptorlake meteorlake graniterapids graniterapids-d arrowlake arrowlake-s lunarlake pantherlake bonnell atom silvermont slm goldmont goldmont-plus tremont gracemont sierraforest grandridge clearwaterforest knl knm x86-64 x86-64-v2 x86-64-v3 x86-64-v4 eden-x2 nano nano-1000 nano-2000 nano-3000 nano-x2 eden-x4 nano-x4 lujiazui yongfeng k8 k8-sse3 opteron opteron-sse3 athlon64 athlon64-sse3 athlon-fx amdfam10 barcelona bdver1 bdver2 bdver3 bdver4 znver1 znver2 znver3 znver4 znver5 btver1 btver2
make[3]: *** [scripts/Makefile.build:203: scripts/mod/empty.o] Error 1
cc1: error: bad value 'native' for '-march=' switch
cc1: note: valid arguments to '-march=' switch are: nocona core2 nehalem corei7 westmere sandybridge corei7-avx ivybridge core-avx-i haswell core-avx2 broadwell skylake skylake-avx512 cannonlake icelake-client rocketlake icelake-server cascadelake tigerlake cooperlake sapphirerapids emeraldrapids alderlake raptorlake meteorlake graniterapids graniterapids-d arrowlake arrowlake-s lunarlake pantherlake bonnell atom silvermont slm goldmont goldmont-plus tremont gracemont sierraforest grandridge clearwaterforest knl knm x86-64 x86-64-v2 x86-64-v3 x86-64-v4 eden-x2 nano nano-1000 nano-2000 nano-3000 nano-x2 eden-x4 nano-x4 lujiazui yongfeng k8 k8-sse3 opteron opteron-sse3 athlon64 athlon64-sse3 athlon-fx amdfam10 barcelona bdver1 bdver2 bdver3 bdver4 znver1 znver2 znver3 znver4 znver5 btver1 btver2
make[3]: *** [scripts/Makefile.build:98: scripts/mod/devicetable-offsets.s] Error 1
make[2]: *** [Makefile:1276: prepare0] Error 2

Caused by commit

  0480bc7e65dc ("x86/kbuild/64: Add the CONFIG_X86_NATIVE_CPU option to locally optimize the kernel with '-march=native'")

I have reverted that commit for today.

$ x86_64-linux-gnu-gcc --version
x86_64-linux-gnu-gcc (Debian 14.2.0-12) 14.2.0

cross build - ppc hosted

-- 
Cheers,
Stephen Rothwell

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Re: linux-next: build failure after merge of the tip tree

[H. Peter Anvin]

On March 23, 2025 11:27:23 PM PDT, Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>Hi all,
>
>After merging the tip tree, today's linux-next build (x86_64 allmodconfig)
>failed like this:
>
>cc1: error: bad value 'native' for '-march=' switch
>cc1: note: valid arguments to '-march=' switch are: nocona core2 nehalem corei7 westmere sandybridge corei7-avx ivybridge core-avx-i haswell core-avx2 broadwell skylake skylake-avx512 cannonlake icelake-client rocketlake icelake-server cascadelake tigerlake cooperlake sapphirerapids emeraldrapids alderlake raptorlake meteorlake graniterapids graniterapids-d arrowlake arrowlake-s lunarlake pantherlake bonnell atom silvermont slm goldmont goldmont-plus tremont gracemont sierraforest grandridge clearwaterforest knl knm x86-64 x86-64-v2 x86-64-v3 x86-64-v4 eden-x2 nano nano-1000 nano-2000 nano-3000 nano-x2 eden-x4 nano-x4 lujiazui yongfeng k8 k8-sse3 opteron opteron-sse3 athlon64 athlon64-sse3 athlon-fx amdfam10 barcelona bdver1 bdver2 bdver3 bdver4 znver1 znver2 znver3 znver4 znver5 btver1 btver2
>make[3]: *** [scripts/Makefile.build:203: scripts/mod/empty.o] Error 1
>cc1: error: bad value 'native' for '-march=' switch
>cc1: note: valid arguments to '-march=' switch are: nocona core2 nehalem corei7 westmere sandybridge corei7-avx ivybridge core-avx-i haswell core-avx2 broadwell skylake skylake-avx512 cannonlake icelake-client rocketlake icelake-server cascadelake tigerlake cooperlake sapphirerapids emeraldrapids alderlake raptorlake meteorlake graniterapids graniterapids-d arrowlake arrowlake-s lunarlake pantherlake bonnell atom silvermont slm goldmont goldmont-plus tremont gracemont sierraforest grandridge clearwaterforest knl knm x86-64 x86-64-v2 x86-64-v3 x86-64-v4 eden-x2 nano nano-1000 nano-2000 nano-3000 nano-x2 eden-x4 nano-x4 lujiazui yongfeng k8 k8-sse3 opteron opteron-sse3 athlon64 athlon64-sse3 athlon-fx amdfam10 barcelona bdver1 bdver2 bdver3 bdver4 znver1 znver2 znver3 znver4 znver5 btver1 btver2
>make[3]: *** [scripts/Makefile.build:98: scripts/mod/devicetable-offsets.s] Error 1
>make[2]: *** [Makefile:1276: prepare0] Error 2
>
>Caused by commit
>
>  0480bc7e65dc ("x86/kbuild/64: Add the CONFIG_X86_NATIVE_CPU option to locally optimize the kernel with '-march=native'")
>
>I have reverted that commit for today.
>
>$ x86_64-linux-gnu-gcc --version
>x86_64-linux-gnu-gcc (Debian 14.2.0-12) 14.2.0
>
>cross build - ppc hosted
>

Cross compiling?

Re: linux-next: build failure after merge of the tip tree

[Stephen Rothwell]

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Hi,

On Sun, 23 Mar 2025 23:29:20 -0700 "H. Peter Anvin" <hpa@zytor.com> wrote:
>
> >$ x86_64-linux-gnu-gcc --version
> >x86_64-linux-gnu-gcc (Debian 14.2.0-12) 14.2.0
> >
> >cross build - ppc hosted
> >  
> 
> Cross compiling?

Yes (see above :-))

-- 
Cheers,
Stephen Rothwell

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[PATCH] x86/kbuild/64: Test for the availability of the -mtune=native compiler flag

[Ingo Molnar]

* Stephen Rothwell <sfr@canb.auug.org.au> wrote:

> Hi,
> 
> On Sun, 23 Mar 2025 23:29:20 -0700 "H. Peter Anvin" <hpa@zytor.com> wrote:
> >
> > >$ x86_64-linux-gnu-gcc --version
> > >x86_64-linux-gnu-gcc (Debian 14.2.0-12) 14.2.0
> > >
> > >cross build - ppc hosted
> > >  
> > 
> > Cross compiling?
> 
> Yes (see above :-))

Does the patch below fix the bug?

Thanks,

	Ingo

=====================>
From: Ingo Molnar <mingo@kernel.org>
Date: Mon, 24 Mar 2025 08:05:19 +0100
Subject: [PATCH] x86/kbuild/64: Test for the availability of the -mtune=native compiler flag

Stephen reported this build failure when cross-compiling:

  cc1: error: bad value 'native' for '-march=' switch

Test for the availability of the -march=native flag.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Tor Vic <torvic9@mailbox.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250324172723.49fb0416@canb.auug.org.au
---
 arch/x86/Kconfig.cpu | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 9d108a54c30a..87bede96e800 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -245,10 +245,14 @@ config MATOM
 
 endchoice
 
+config CC_HAS_MARCH_NATIVE
+	# This flag might not be available in cross-compilers:
+	def_bool $(cc-option, -march=native)
+
 config X86_NATIVE_CPU
 	bool "Build and optimize for local/native CPU"
 	depends on X86_64
-	default n
+	depends on CC_HAS_MARCH_NATIVE
 	help
 	  Optimize for the current CPU used to compile the kernel.
 	  Use this option if you intend to build the kernel for your

Re: [PATCH] x86/kbuild/64: Test for the availability of the -mtune=native compiler flag

[Stephen Rothwell]

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Hi Ingo,

On Mon, 24 Mar 2025 08:10:00 +0100 Ingo Molnar <mingo@kernel.org> wrote:
>
> Does the patch below fix the bug?

Yes, it does.  Thanks.

Tested-by: Stephen Rothwell <sfr@canb.auug.org.au> # build test

-- 
Cheers,
Stephen Rothwell

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Re: [PATCH] x86/kbuild/64: Test for the availability of the -mtune=native compiler flag

[Ingo Molnar]

* Stephen Rothwell <sfr@canb.auug.org.au> wrote:

> Hi Ingo,
> 
> On Mon, 24 Mar 2025 08:10:00 +0100 Ingo Molnar <mingo@kernel.org> wrote:
> >
> > Does the patch below fix the bug?
> 
> Yes, it does.  Thanks.
> 
> Tested-by: Stephen Rothwell <sfr@canb.auug.org.au> # build test

Thank you!

	Ingo

[tip: x86/kconfig] x86/kbuild/64: Test for the availability of the -mtune=native compiler flag

[tip-bot2 for Ingo Molnar]

The following commit has been merged into the x86/kconfig branch of tip:

Commit-ID:     01412081863aa81db47423d5719f2726d2a00a32
Gitweb:        https://git.kernel.org/tip/01412081863aa81db47423d5719f2726d2a00a32
Author:        Ingo Molnar <mingo@kernel.org>
AuthorDate:    Mon, 24 Mar 2025 08:05:19 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 25 Mar 2025 08:24:06 +01:00

x86/kbuild/64: Test for the availability of the -mtune=native compiler flag

Stephen reported this build failure when cross-compiling:

  cc1: error: bad value 'native' for '-march=' switch

Test for the availability of the -march=native flag.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Stephen Rothwell <sfr@canb.auug.org.au> # build test
Cc: Tor Vic <torvic9@mailbox.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250324172723.49fb0416@canb.auug.org.au
---
 arch/x86/Kconfig.cpu | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 9d108a5..87bede9 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -245,10 +245,14 @@ config MATOM
 
 endchoice
 
+config CC_HAS_MARCH_NATIVE
+	# This flag might not be available in cross-compilers:
+	def_bool $(cc-option, -march=native)
+
 config X86_NATIVE_CPU
 	bool "Build and optimize for local/native CPU"
 	depends on X86_64
-	default n
+	depends on CC_HAS_MARCH_NATIVE
 	help
 	  Optimize for the current CPU used to compile the kernel.
 	  Use this option if you intend to build the kernel for your