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Subject[PATCH 4.14 19/72] x86/build: Fix compiler support check for CONFIG_RETPOLINE
4.14-stable review patch.  If anyone has any objections, please let me know.


From: Masahiro Yamada <>

commit 25896d073d8a0403b07e6dec56f58e6c33678207 upstream.

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 <>
Tested-by: Meelis Roos <>
Signed-off-by: Masahiro Yamada <>
Acked-by: Zhenzhong Duan <>
Cc: Borislav Petkov <>
Cc: Linus Torvalds <>
Cc: Peter Zijlstra <>
Cc: Thomas Gleixner <>
Cc: Zhenzhong Duan <>
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
Signed-off-by: Ingo Molnar <>
Signed-off-by: Sasha Levin <>
Cc: Gi-Oh Kim <>
Signed-off-by: Greg Kroah-Hartman <>

arch/x86/Makefile | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -241,9 +241,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwin

# Avoid indirect branches in kernel to deal with Spectre
- $(error You are building kernel with non-retpoline compiler, please update your compiler.)

@@ -260,6 +257,13 @@ archprepare:
$(Q)$(MAKE) $(build)=arch/x86/purgatory arch/x86/purgatory/kexec-purgatory.c
+ @echo "You are building kernel with non-retpoline compiler." >&2
+ @echo "Please update your compiler." >&2
+ @false

# Kernel objects

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