Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.8 25/67] kbuild: Steal gccs pie from the very beginning | Date | Thu, 24 Nov 2016 16:27:19 +0100 |
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4.8-stable review patch. If anyone has any objections, please let me know.
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From: Borislav Petkov <bp@suse.de>
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>
--- Makefile | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
--- a/Makefile +++ b/Makefile @@ -399,11 +399,12 @@ KBUILD_CFLAGS := -Wall -Wundef -Wstric -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
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