target/linux/brcm2708/patches-4.4/0552-kbuild-Steal-gcc-s-pie-from-the-very-beginning.patch

   1 From e1c194ad704d298d6914e5b1efc4afee41a18a4c Mon Sep 17 00:00:00 2001
   2 From: Borislav Petkov <bp@suse.de>
   3 Date: Mon, 14 Nov 2016 19:41:31 +0100
   4 Subject: [PATCH] kbuild: Steal gcc's pie from the very beginning
   5
   6 commit c6a385539175ebc603da53aafb7753d39089f32e upstream.
   7
   8 So Sebastian turned off the PIE for kernel builds but that was too late
   9 - Kbuild.include already uses KBUILD_CFLAGS and trying to disable gcc
  10 options with, say cc-disable-warning, fails:
  11
  12   gcc -D__KERNEL__ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs
  13   ...
  14   -Wno-sign-compare -fno-asynchronous-unwind-tables -Wframe-address -c -x c /dev/null -o .31392.tmp
  15   /dev/null:1:0: error: code model kernel does not support PIC mode
  16
  17 because that returns an error and we can't disable the warning. For
  18 example in this case:
  19
  20 KBUILD_CFLAGS   += $(call cc-disable-warning,frame-address,)
  21
  22 which leads to gcc issuing all those warnings again.
  23
  24 So let's turn off PIE/PIC at the earliest possible moment, when we
  25 declare KBUILD_CFLAGS so that cc-disable-warning picks it up too.
  26
  27 Also, we need the $(call cc-option ...) because -fno-PIE is supported
  28 since gcc v3.4 and our lowest supported gcc version is 3.2 right now.
  29
  30 Signed-off-by: Borislav Petkov <bp@suse.de>
  31 Cc: Ben Hutchings <ben@decadent.org.uk>
  32 Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  33 Signed-off-by: Michal Marek <mmarek@suse.com>
  34 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  35 ---
  36  Makefile | 2 --
  37  1 file changed, 2 deletions(-)
  38
  39 --- a/Makefile
  40 +++ b/Makefile
  41 @@ -624,8 +624,6 @@ KBUILD_CFLAGS       += $(call cc-disable-warni
  42  KBUILD_CFLAGS  += $(call cc-disable-warning, format-truncation)
  43  KBUILD_CFLAGS  += $(call cc-disable-warning, format-overflow)
  44  KBUILD_CFLAGS  += $(call cc-disable-warning, int-in-bool-context)
  45 -KBUILD_CFLAGS  += $(call cc-option,-fno-PIE)
  46 -KBUILD_AFLAGS  += $(call cc-option,-fno-PIE)
  47
  48  ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
  49  KBUILD_CFLAGS  += -Os $(EXTRA_OPTIMIZATION)