• Borislav Petkov's avatar
    kbuild: Steal gcc's pie from the very beginning · fcee7d4b
    Borislav Petkov authored
    commit c6a38553 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: default avatarBorislav Petkov <bp@suse.de>
    Cc: Ben Hutchings <ben@decadent.org.uk>
    Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
    [bwh: Backported to 3.16: adjust context]
    Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
    fcee7d4b
Makefile 51.4 KB