[PATCH] Makefile: disable PIE before testing asm goto

From: Michal Kubecek
Date: Wed May 16 2018 - 01:38:17 EST


Since commit e501ce957a78 ("x86: Force asm-goto"), aarch64 build on
distributions which enable PIE by default (e.g. openSUSE Tumbleweed) does
not detect support for asm goto correctly. The problem is that ARM specific
part of scripts/gcc-goto.sh fails with PIE even with recent gcc versions.
Moving the asm goto detection up in Makefile put it before the place where
we disable PIE. As a result, kernel is built without jump label support.

Move the lines disabling PIE before the asm goto test to make it work.

Fixes: e501ce957a78 ("x86: Force asm-goto")
Reported-by: Andreas Faerber <afaerber@xxxxxxxx>
Signed-off-by: Michal Kubecek <mkubecek@xxxxxxx>
---
Makefile | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index ba3106b36597..5532a15c4781 100644
--- a/Makefile
+++ b/Makefile
@@ -500,6 +500,9 @@ RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG)))
export RETPOLINE_CFLAGS

+KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
+KBUILD_AFLAGS += $(call cc-option,-fno-PIE)
+
# check for 'asm goto'
ifeq ($(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
CC_HAVE_ASM_GOTO := 1
@@ -621,8 +624,6 @@ endif # $(dot-config)
# Defaults to vmlinux, but the arch makefile usually adds further targets
all: vmlinux

-KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
-KBUILD_AFLAGS += $(call cc-option,-fno-PIE)
CFLAGS_GCOV := -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,)
export CFLAGS_GCOV CFLAGS_KCOV

--
2.16.3