[PATCH] purgatory: force PIC/PIE/SSP off

[Laurent Dufour]

On 16/04/2015 07:15, Mike Frysinger wrote:
> From: Mike Frysinger <vapier at chromium.org>
> 
> If the toolchain has these things turned on automatically, then the
> purgatory code might be miscompiled leading to runtime errors like:
> Unhandled rela relocation: R_X86_64_GOTPC64
> 
> It might look like the problem is with the kernel when in reality,
> kexec is complaining about the purgatory module.  Force off harden
> features that don't make sense in kernel space.
> 
> Signed-off-by: Mike Frysinger <vapier at chromium.org>
> ---
>  purgatory/Makefile | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/purgatory/Makefile b/purgatory/Makefile
> index 2d6b2c0..2b5c061 100644
> --- a/purgatory/Makefile
> +++ b/purgatory/Makefile
> @@ -49,7 +49,8 @@ $(PURGATORY): CC=$(TARGET_CC)
>  $(PURGATORY): CFLAGS+=$(PURGATORY_EXTRA_CFLAGS) \
>  		      $($(ARCH)_PURGATORY_EXTRA_CFLAGS) \
>  		      -Os -fno-builtin -ffreestanding \
> -		      -fno-zero-initialized-in-bss
> +		      -fno-zero-initialized-in-bss \
> +		      -fno-PIC -fno-PIE -fno-stack-protector

Some architectures (ppc64 and s390) are already setting
-fno-stack-protector in purgatory/arch/x/Makefile through
x_PURGATORY_EXTRA_CFLAGS.

It would be cleaner to remove those per architecture settings if you set
it globally.

Cheers,
Laurent.