tree 3debe781c316c3b5a972767f13b2fc1e4a608bfa
parent e543f094a38ad006454e9bc54ebc6b94702f11a2
author Borislav Petkov <bp@suse.de> 1479148891 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1480150492 +0100

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>