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authorBorislav Petkov <bp@suse.de>2016-11-14 19:41:31 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-11-26 09:56:55 +0100
commit56df604296c2b6f785e627681757949a461b3a34 (patch)
tree5d531e8d41786f467c72c22bcdd462ea9d724475
parente14754cb8f0cbd32db8239fcf5f4e15b17ae9444 (diff)
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 <bp@suse.de> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Michal Marek <mmarek@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--Makefile7
1 files changed, 3 insertions, 4 deletions
diff --git a/Makefile b/Makefile
index 0e7803526c02..50f49c312236 100644
--- a/Makefile
+++ b/Makefile
@@ -399,11 +399,12 @@ KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-fno-strict-aliasing -fno-common \
-Werror-implicit-function-declaration \
-Wno-format-security \
- -std=gnu89
+ -std=gnu89 $(call cc-option,-fno-PIE)
+
KBUILD_AFLAGS_KERNEL :=
KBUILD_CFLAGS_KERNEL :=
-KBUILD_AFLAGS := -D__ASSEMBLY__
+KBUILD_AFLAGS := -D__ASSEMBLY__ $(call cc-option,-fno-PIE)
KBUILD_AFLAGS_MODULE := -DMODULE
KBUILD_CFLAGS_MODULE := -DMODULE
KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
@@ -622,8 +623,6 @@ include arch/$(SRCARCH)/Makefile
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,)
-KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
-KBUILD_AFLAGS += $(call cc-option,-fno-PIE)
ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
KBUILD_CFLAGS += -Os