* [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE
@ 2018-12-05 6:27 Masahiro Yamada
2018-12-05 6:59 ` Meelis Roos
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Masahiro Yamada @ 2018-12-05 6:27 UTC (permalink / raw)
To: Ingo Molnar, Thomas Gleixner, x86
Cc: Zhenzhong Duan, Meelis Roos, Masahiro Yamada, H. Peter Anvin,
Borislav Petkov, linux-kernel
It is troublesome to add a diagnostic like this to the Makefile
parse stage because the top-level Makefile could be parsed with
a stale include/config/auto.conf.
Once you are hit by the error about non-retpoline compiler, the
compilation still breaks even after disabling CONFIG_RETPOLINE.
The easiest fix is to move this check to the "archprepare" like commit
829fe4aa9ac1 ("x86: Allow generating user-space headers without a
compiler") did.
Link: https://lkml.org/lkml/2018/12/4/206
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---
Changes in v2:
- Revive ifdef CONFIG_RETPOLINE surrounding the KBUILD_CFLAGS addition
- Rephase the commit log a bit, hoping the cause of the issue will be clearer
arch/x86/Makefile | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index f5d7f41..75ef499 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -220,9 +220,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# Avoid indirect branches in kernel to deal with Spectre
ifdef CONFIG_RETPOLINE
-ifeq ($(RETPOLINE_CFLAGS),)
- $(error You are building kernel with non-retpoline compiler, please update your compiler.)
-endif
KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
endif
@@ -307,6 +304,13 @@ ifndef CC_HAVE_ASM_GOTO
@echo Compiler lacks asm-goto support.
@exit 1
endif
+ifdef CONFIG_RETPOLINE
+ifeq ($(RETPOLINE_CFLAGS),)
+ @echo "You are building kernel with non-retpoline compiler." >&2
+ @echo "Please update your compiler." >&2
+ @false
+endif
+endif
archclean:
$(Q)rm -rf $(objtree)/arch/i386
--
2.7.4
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE
2018-12-05 6:27 [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE Masahiro Yamada
@ 2018-12-05 6:59 ` Meelis Roos
2018-12-05 7:10 ` Zhenzhong Duan
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Meelis Roos @ 2018-12-05 6:59 UTC (permalink / raw)
To: Masahiro Yamada, Ingo Molnar, Thomas Gleixner, x86
Cc: Zhenzhong Duan, Meelis Roos, H. Peter Anvin, Borislav Petkov,
linux-kernel
05.12.18 08:27 Masahiro Yamada kirjutas:
> The easiest fix is to move this check to the "archprepare" like commit
> 829fe4aa9ac1 ("x86: Allow generating user-space headers without a
> compiler") did.
>
> Link: https://lkml.org/lkml/2018/12/4/206
> Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
> Reported-by: Meelis Roos <mroos@linux.ee>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
>
> Changes in v2:
> - Revive ifdef CONFIG_RETPOLINE surrounding the KBUILD_CFLAGS addition
> - Rephase the commit log a bit, hoping the cause of the issue will be clearer
Works for me - first it did
scripts/kconfig/conf --syncconfig Kconfig
and then started compiling. The #define is gone from include/linux.
Thank you!
--
Meelis Roos <mroos@linux.ee>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE
2018-12-05 6:27 [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE Masahiro Yamada
2018-12-05 6:59 ` Meelis Roos
@ 2018-12-05 7:10 ` Zhenzhong Duan
2018-12-18 13:20 ` Gi-Oh Kim
2018-12-05 7:45 ` [tip:x86/urgent] x86/build: Fix " tip-bot for Masahiro Yamada
2018-12-05 7:48 ` tip-bot for Masahiro Yamada
3 siblings, 1 reply; 6+ messages in thread
From: Zhenzhong Duan @ 2018-12-05 7:10 UTC (permalink / raw)
To: Masahiro Yamada, Ingo Molnar, Thomas Gleixner, x86
Cc: Meelis Roos, H. Peter Anvin, Borislav Petkov, linux-kernel
On 2018/12/5 14:27, Masahiro Yamada wrote:
> It is troublesome to add a diagnostic like this to the Makefile
> parse stage because the top-level Makefile could be parsed with
> a stale include/config/auto.conf.
>
> Once you are hit by the error about non-retpoline compiler, the
> compilation still breaks even after disabling CONFIG_RETPOLINE.
>
> The easiest fix is to move this check to the "archprepare" like commit
> 829fe4aa9ac1 ("x86: Allow generating user-space headers without a
> compiler") did.
>
> Link: https://lkml.org/lkml/2018/12/4/206
> Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
> Reported-by: Meelis Roos <mroos@linux.ee>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
>
> Changes in v2:
> - Revive ifdef CONFIG_RETPOLINE surrounding the KBUILD_CFLAGS addition
> - Rephase the commit log a bit, hoping the cause of the issue will be clearer
>
> arch/x86/Makefile | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index f5d7f41..75ef499 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -220,9 +220,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
>
> # Avoid indirect branches in kernel to deal with Spectre
> ifdef CONFIG_RETPOLINE
> -ifeq ($(RETPOLINE_CFLAGS),)
> - $(error You are building kernel with non-retpoline compiler, please update your compiler.)
> -endif
> KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
> endif
>
> @@ -307,6 +304,13 @@ ifndef CC_HAVE_ASM_GOTO
> @echo Compiler lacks asm-goto support.
> @exit 1
> endif
> +ifdef CONFIG_RETPOLINE
> +ifeq ($(RETPOLINE_CFLAGS),)
> + @echo "You are building kernel with non-retpoline compiler." >&2
> + @echo "Please update your compiler." >&2
> + @false
> +endif
> +endif
>
> archclean:
> $(Q)rm -rf $(objtree)/arch/i386
Acked-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
--
Regards
Zhenzhong
^ permalink raw reply [flat|nested] 6+ messages in thread
* [tip:x86/urgent] x86/build: Fix compiler support check for CONFIG_RETPOLINE
2018-12-05 6:27 [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE Masahiro Yamada
2018-12-05 6:59 ` Meelis Roos
2018-12-05 7:10 ` Zhenzhong Duan
@ 2018-12-05 7:45 ` tip-bot for Masahiro Yamada
2018-12-05 7:48 ` tip-bot for Masahiro Yamada
3 siblings, 0 replies; 6+ messages in thread
From: tip-bot for Masahiro Yamada @ 2018-12-05 7:45 UTC (permalink / raw)
To: linux-tip-commits
Cc: mingo, tglx, linux-kernel, zhenzhong.duan, torvalds,
yamada.masahiro, mroos, peterz, bp, hpa
Commit-ID: 10b87bc9f630a38a7f0c1e7cf13ff23fea1692ec
Gitweb: https://git.kernel.org/tip/10b87bc9f630a38a7f0c1e7cf13ff23fea1692ec
Author: Masahiro Yamada <yamada.masahiro@socionext.com>
AuthorDate: Wed, 5 Dec 2018 15:27:19 +0900
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 5 Dec 2018 08:42:09 +0100
x86/build: Fix compiler support check for CONFIG_RETPOLINE
It is troublesome to add a diagnostic like this to the Makefile
parse stage because the top-level Makefile could be parsed with
a stale include/config/auto.conf.
Once you are hit by the error about non-retpoline compiler, the
compilation still breaks even after disabling CONFIG_RETPOLINE.
The easiest fix is to move this check to the "archprepare" like
this commit did:
829fe4aa9ac1 ("x86: Allow generating user-space headers without a compiler")
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
Link: http://lkml.kernel.org/r/1543991239-18476-1-git-send-email-yamada.masahiro@socionext.com
Link: https://lkml.org/lkml/2018/12/4/206
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/Makefile | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index f5d7f4134524..75ef499a66e2 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -220,9 +220,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# Avoid indirect branches in kernel to deal with Spectre
ifdef CONFIG_RETPOLINE
-ifeq ($(RETPOLINE_CFLAGS),)
- $(error You are building kernel with non-retpoline compiler, please update your compiler.)
-endif
KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
endif
@@ -307,6 +304,13 @@ ifndef CC_HAVE_ASM_GOTO
@echo Compiler lacks asm-goto support.
@exit 1
endif
+ifdef CONFIG_RETPOLINE
+ifeq ($(RETPOLINE_CFLAGS),)
+ @echo "You are building kernel with non-retpoline compiler." >&2
+ @echo "Please update your compiler." >&2
+ @false
+endif
+endif
archclean:
$(Q)rm -rf $(objtree)/arch/i386
^ permalink raw reply [flat|nested] 6+ messages in thread
* [tip:x86/urgent] x86/build: Fix compiler support check for CONFIG_RETPOLINE
2018-12-05 6:27 [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE Masahiro Yamada
` (2 preceding siblings ...)
2018-12-05 7:45 ` [tip:x86/urgent] x86/build: Fix " tip-bot for Masahiro Yamada
@ 2018-12-05 7:48 ` tip-bot for Masahiro Yamada
3 siblings, 0 replies; 6+ messages in thread
From: tip-bot for Masahiro Yamada @ 2018-12-05 7:48 UTC (permalink / raw)
To: linux-tip-commits
Cc: peterz, tglx, torvalds, zhenzhong.duan, mroos, linux-kernel,
mingo, bp, yamada.masahiro, hpa
Commit-ID: 25896d073d8a0403b07e6dec56f58e6c33678207
Gitweb: https://git.kernel.org/tip/25896d073d8a0403b07e6dec56f58e6c33678207
Author: Masahiro Yamada <yamada.masahiro@socionext.com>
AuthorDate: Wed, 5 Dec 2018 15:27:19 +0900
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 5 Dec 2018 08:44:02 +0100
x86/build: Fix compiler support check for CONFIG_RETPOLINE
It is troublesome to add a diagnostic like this to the Makefile
parse stage because the top-level Makefile could be parsed with
a stale include/config/auto.conf.
Once you are hit by the error about non-retpoline compiler, the
compilation still breaks even after disabling CONFIG_RETPOLINE.
The easiest fix is to move this check to the "archprepare" like
this commit did:
829fe4aa9ac1 ("x86: Allow generating user-space headers without a compiler")
Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
Link: http://lkml.kernel.org/r/1543991239-18476-1-git-send-email-yamada.masahiro@socionext.com
Link: https://lkml.org/lkml/2018/12/4/206
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/Makefile | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index f5d7f4134524..75ef499a66e2 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -220,9 +220,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# Avoid indirect branches in kernel to deal with Spectre
ifdef CONFIG_RETPOLINE
-ifeq ($(RETPOLINE_CFLAGS),)
- $(error You are building kernel with non-retpoline compiler, please update your compiler.)
-endif
KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
endif
@@ -307,6 +304,13 @@ ifndef CC_HAVE_ASM_GOTO
@echo Compiler lacks asm-goto support.
@exit 1
endif
+ifdef CONFIG_RETPOLINE
+ifeq ($(RETPOLINE_CFLAGS),)
+ @echo "You are building kernel with non-retpoline compiler." >&2
+ @echo "Please update your compiler." >&2
+ @false
+endif
+endif
archclean:
$(Q)rm -rf $(objtree)/arch/i386
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE
2018-12-05 7:10 ` Zhenzhong Duan
@ 2018-12-18 13:20 ` Gi-Oh Kim
0 siblings, 0 replies; 6+ messages in thread
From: Gi-Oh Kim @ 2018-12-18 13:20 UTC (permalink / raw)
To: zhenzhong.duan
Cc: yamada.masahiro, mingo, tglx, x86, mroos, hpa, Borislav Petkov,
linux-kernel
On Wed, Dec 5, 2018 at 8:11 AM Zhenzhong Duan <zhenzhong.duan@oracle.com> wrote:
>
>
> On 2018/12/5 14:27, Masahiro Yamada wrote:
> > It is troublesome to add a diagnostic like this to the Makefile
> > parse stage because the top-level Makefile could be parsed with
> > a stale include/config/auto.conf.
> >
> > Once you are hit by the error about non-retpoline compiler, the
> > compilation still breaks even after disabling CONFIG_RETPOLINE.
> >
> > The easiest fix is to move this check to the "archprepare" like commit
> > 829fe4aa9ac1 ("x86: Allow generating user-space headers without a
> > compiler") did.
> >
> > Link: https://lkml.org/lkml/2018/12/4/206
> > Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
> > Reported-by: Meelis Roos <mroos@linux.ee>
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> > ---
> >
> > Changes in v2:
> > - Revive ifdef CONFIG_RETPOLINE surrounding the KBUILD_CFLAGS addition
> > - Rephase the commit log a bit, hoping the cause of the issue will be clearer
> >
> > arch/x86/Makefile | 10 +++++++---
> > 1 file changed, 7 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> > index f5d7f41..75ef499 100644
> > --- a/arch/x86/Makefile
> > +++ b/arch/x86/Makefile
> > @@ -220,9 +220,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
> >
> > # Avoid indirect branches in kernel to deal with Spectre
> > ifdef CONFIG_RETPOLINE
> > -ifeq ($(RETPOLINE_CFLAGS),)
> > - $(error You are building kernel with non-retpoline compiler, please update your compiler.)
> > -endif
> > KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
> > endif
> >
> > @@ -307,6 +304,13 @@ ifndef CC_HAVE_ASM_GOTO
> > @echo Compiler lacks asm-goto support.
> > @exit 1
> > endif
> > +ifdef CONFIG_RETPOLINE
> > +ifeq ($(RETPOLINE_CFLAGS),)
> > + @echo "You are building kernel with non-retpoline compiler." >&2
> > + @echo "Please update your compiler." >&2
> > + @false
> > +endif
> > +endif
> >
> > archclean:
> > $(Q)rm -rf $(objtree)/arch/i386
> Acked-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
>
> --
> Regards
> Zhenzhong
>
Hi,
I think this patch needs to be merged to linux-stable 4.14.y branch.
Following is what I did to reproduce the problem.
The problem is gone after applying the patch.
1. I created and installed a headers package as following.
make -j7 deb-pkg
cd ..
sudo dpkg -i linux-headers-4.14.89+_4.14.89+-18_amd64.deb
2. I managed to re-produce the same problem as following.
gohkim@ws00837:~/study/drv$ make -C /usr/src/linux-headers-4.14.89+/
kernelrelease
make: Entering directory '/usr/src/linux-headers-4.14.89+'
arch/x86/Makefile:245: *** You are building kernel with non-retpoline
compiler, please update your compiler.. Stop.
make: Leaving directory '/usr/src/linux-headers-4.14.89+'
3. Weird thing is that it works fine if I use sudo command.
gohkim@ws00837:~/study/drv$ sudo make -C
/usr/src/linux-headers-4.14.89+/ kernelrelease
make: Entering directory '/usr/src/linux-headers-4.14.89+'
HOSTCC scripts/kconfig/conf.o
HOSTCC scripts/kconfig/zconf.tab.o
HOSTLD scripts/kconfig/conf
scripts/kconfig/conf --silentoldconfig Kconfig
4.14.89
make: Leaving directory '/usr/src/linux-headers-4.14.89+'
--
GIOH KIM
Linux Kernel Entwickler
1&1 IONOS Cloud GmbH
Greifswalder Str. 207
D - 10405 Berlin
Tel: +49 176 2697 8962
Fax: +49 30 577 008 299
Email: gi-oh.kim@cloud.ionos.com
URL: https://www.ionos.com
Sitz der Gesellschaft: Berlin
Registergericht: Amtsgericht Charlottenburg, HRB 125506 B
Geschäftsführer: Achim Weiss, Matthias Steinberg, Christoph Steffens
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-12-18 13:21 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-12-05 6:27 [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE Masahiro Yamada
2018-12-05 6:59 ` Meelis Roos
2018-12-05 7:10 ` Zhenzhong Duan
2018-12-18 13:20 ` Gi-Oh Kim
2018-12-05 7:45 ` [tip:x86/urgent] x86/build: Fix " tip-bot for Masahiro Yamada
2018-12-05 7:48 ` tip-bot for Masahiro Yamada
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