| Message ID | 1543991239-18476-1-git-send-email-yamada.masahiro@socionext.com |
|---|---|
| State | Accepted |
| Commit | 25896d073d8a0403b07e6dec56f58e6c33678207 |
| Headers | show |
| Series | [v2] x86/build: fix compiler support check for CONFIG_RETPOLINE | expand |
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>
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 $(objtree)/arch/i386 Acked-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> -- Regards Zhenzhong
On Wed, Dec 5, 2018 at 8:11 AM Zhenzhong Duan <zhenzhong.duan@oracle.com> wrote: > > > On 2018/12/5 14:27, Masahiro Yamada wrote: > > It is troublesome to add a diagnostic like this to the Makefile > > parse stage because the top-level Makefile could be parsed with > > a stale include/config/auto.conf. > > > > Once you are hit by the error about non-retpoline compiler, the > > compilation still breaks even after disabling CONFIG_RETPOLINE. > > > > The easiest fix is to move this check to the "archprepare" like commit > > 829fe4aa9ac1 ("x86: Allow generating user-space headers without a > > compiler") did. > > > > Link: https://lkml.org/lkml/2018/12/4/206 > > Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") > > Reported-by: Meelis Roos <mroos@linux.ee> > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > > --- > > > > Changes in v2: > > - Revive ifdef CONFIG_RETPOLINE surrounding the KBUILD_CFLAGS addition > > - Rephase the commit log a bit, hoping the cause of the issue will be clearer > > > > arch/x86/Makefile | 10 +++++++--- > > 1 file changed, 7 insertions(+), 3 deletions(-) > > > > diff --git a/arch/x86/Makefile b/arch/x86/Makefile > > index f5d7f41..75ef499 100644 > > --- a/arch/x86/Makefile > > +++ b/arch/x86/Makefile > > @@ -220,9 +220,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables > > > > # Avoid indirect branches in kernel to deal with Spectre > > ifdef CONFIG_RETPOLINE > > -ifeq ($(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
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
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(-) -- 2.7.4