>From 2c72542688476168920c027cdc28c6764387ecac Mon Sep 17 00:00:00 2001 From: Sven Joachim Date: Mon, 24 Oct 2016 18:17:26 +0200 Subject: [PATCH] kbuild: add -fno-pie to KBUILD_CFLAGS If GCC is configured with --enable-default-pie, the build fails early because this default is incompatible with -mcmodel=kernel. kernel/bounds.c:1:0: error: code model kernel does not support PIC mode Avoid that by adding -fno-pie to KBUILD_CFLAGS, if supported by the compiler. This flag is also needed in the x86_64 stack-protector test script which otherwise errors out. Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong available but compiler is broken See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=841420 and https://bugs.launchpad.net/ubuntu/+source/gcc-defaults/+bug/1574982. Signed-off-by: Sven Joachim --- Makefile | 1 + scripts/gcc-x86_64-has-stack-protector.sh | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/Makefile b/Makefile index 93beca4..81ef816 100644 --- a/Makefile +++ b/Makefile @@ -619,6 +619,7 @@ ARCH_AFLAGS := ARCH_CFLAGS := include arch/$(SRCARCH)/Makefile +KBUILD_CFLAGS += $(call cc-option,-fno-pie,) KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,) KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,) diff --git a/scripts/gcc-x86_64-has-stack-protector.sh b/scripts/gcc-x86_64-has-stack-protector.sh index 973e8c1..274cba1 100755 --- a/scripts/gcc-x86_64-has-stack-protector.sh +++ b/scripts/gcc-x86_64-has-stack-protector.sh @@ -1,6 +1,6 @@ #!/bin/sh -echo "int foo(void) { char X[200]; return 3; }" | $* -S -x c -c -O0 -mcmodel=kernel -fstack-protector - -o - 2> /dev/null | grep -q "%gs" +echo "int foo(void) { char X[200]; return 3; }" | $* -S -x c -c -O0 -mcmodel=kernel -fno-pie -fstack-protector - -o - 2> /dev/null | grep -q "%gs" if [ "$?" -eq "0" ] ; then echo y else -- 2.10.1