From e1c194ad704d298d6914e5b1efc4afee41a18a4c Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 14 Nov 2016 19:41:31 +0100 Subject: [PATCH] kbuild: Steal gcc's pie from the very beginning commit c6a385539175ebc603da53aafb7753d39089f32e upstream. So Sebastian turned off the PIE for kernel builds but that was too late - Kbuild.include already uses KBUILD_CFLAGS and trying to disable gcc options with, say cc-disable-warning, fails: gcc -D__KERNEL__ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs ... -Wno-sign-compare -fno-asynchronous-unwind-tables -Wframe-address -c -x c /dev/null -o .31392.tmp /dev/null:1:0: error: code model kernel does not support PIC mode because that returns an error and we can't disable the warning. For example in this case: KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,) which leads to gcc issuing all those warnings again. So let's turn off PIE/PIC at the earliest possible moment, when we declare KBUILD_CFLAGS so that cc-disable-warning picks it up too. Also, we need the $(call cc-option ...) because -fno-PIE is supported since gcc v3.4 and our lowest supported gcc version is 3.2 right now. Signed-off-by: Borislav Petkov Cc: Ben Hutchings Cc: Sebastian Andrzej Siewior Signed-off-by: Michal Marek Signed-off-by: Greg Kroah-Hartman --- Makefile | 2 -- 1 file changed, 2 deletions(-) --- a/Makefile +++ b/Makefile @@ -624,8 +624,6 @@ KBUILD_CFLAGS += $(call cc-disable-warni KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation) KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) KBUILD_CFLAGS += $(call cc-disable-warning, int-in-bool-context) -KBUILD_CFLAGS += $(call cc-option,-fno-PIE) -KBUILD_AFLAGS += $(call cc-option,-fno-PIE) ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE KBUILD_CFLAGS += -Os $(EXTRA_OPTIMIZATION)