On Thu, Dec 13, 2018 at 5:47 AM Sasha Levin sashal@kernel.org wrote:
From: Masahiro Yamada yamada.masahiro@socionext.com
[ Upstream commit 25896d073d8a0403b07e6dec56f58e6c33678207 ]
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@s... Link: https://lkml.org/lkml/2018/12/4/206 Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org
arch/x86/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 9298f0f3817a..b84f61bc5e7a 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -223,9 +223,6 @@ 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 += $(RETPOLINE_CFLAGS) endif
@@ -303,6 +300,13 @@ ifndef CC_HAVE_ASM_GOTO @echo Compiler lacks asm-goto support. @exit 1 endif +ifdef CONFIG_RETPOLINE +ifeq ($(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 $(objtree)/arch/i386 -- 2.19.1
Hi Greg,
I think this patch needs to be merged to linux-stable 4.14.y branch. I found out the same problem when I built my drivers on linux-stable 4.14.86. Following is what I did to reproduce the problem. The problem is gone after applying the patch.
1. I created and installed a headers package as following. make -j7 deb-pkg cd .. sudo dpkg -i linux-headers-4.14.89+_4.14.89+-18_amd64.deb
2. I managed to re-produce the same problem as following. gohkim@ws00837:~/study/drv$ 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+'