[Buildroot] [PATCH 1/1] Config.in: disable PIC/PIE if the toolchain does not support PIE

[Matthew Weber]

Fabrice,

On Sun, Oct 27, 2019 at 5:03 PM Fabrice Fontaine
<fontaine.fabrice at gmail.com> wrote:
>
> m68k does not seem to really support PIE as it raises the following
> build failure with aer-inject:
> /usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-1/output/host/opt/ext-toolchain/bin/../lib/gcc/m68k-buildroot-linux-uclibc/7.4.0/../../../../m68k-buildroot-linux-uclibc/bin/ld: /usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-1/output/host/m68k-buildroot-linux-uclibc/sysroot/usr/lib/Scrt1.o: in function `lib_main':
> (.text+0x4): undefined reference to `__shared_flat_add_library'
> /usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-1/output/host/opt/ext-toolchain/bin/../lib/gcc/m68k-buildroot-linux-uclibc/7.4.0/../../../../m68k-buildroot-linux-uclibc/bin/ld: final link failed: bad value
>

I wonder where this ever got to add support as in 2006 as they were
trying for m68k.
https://lists.uclibc.org/pipermail/uclibc/2006-July/036766.html

> We also have another build failure with uclibc on microblazeel:
> /home/buildroot/autobuild/instance-1/output-1/host/lib/gcc/microblazeel-buildroot-linux-uclibc/8.3.0/../../../../microblazeel-buildroot-linux-uclibc/bin/ld: final link failed: bad value
> collect2: error: ld returned 1 exit status
> Makefile.in:114: recipe for target '../utils/getconf' failed
>

This one looks like it might be fixable and an issue with compile
flags missing but link time options being set.  I'm wondering what its
doing as the error is in the target install step of the package.


> So add a BR2_TOOLCHAIN_SUPPORTS_PIE dependency on BR2_PIC_PIE
>
> Fixes:
>  - http://autobuild.buildroot.net/results/4cdd6f0368cc9d3c6e88f01b1a8929eb0839b638
>  - http://autobuild.buildroot.net/results/a82a484409149d7f9aff6140ddcb89f627f508c7
>
> Signed-off-by: Fabrice Fontaine <fontaine.fabrice at gmail.com>
> ---
>  Config.in | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/Config.in b/Config.in
> index ebbb6b41f4..010b0774e3 100644
> --- a/Config.in
> +++ b/Config.in
> @@ -697,10 +697,15 @@ comment "Security Hardening Options"
>  config BR2_PIC_PIE
>         bool "Build code with PIC/PIE"
>         depends on BR2_SHARED_LIBS
> +       depends on BR2_TOOLCHAIN_SUPPORTS_PIE
>         help
>           Generate Position-Independent Code (PIC) and link
>           Position-Independent Executables (PIE).
>
> +comment "PIC/PIE needs a toolchain w/ PIE"
> +       depends on BR2_SHARED_LIBS
> +       depends on !BR2_TOOLCHAIN_SUPPORTS_PIE
> +
>  choice
>         bool "Stack Smashing Protection"
>         default BR2_SSP_ALL if BR2_ENABLE_SSP # legacy
> @@ -783,12 +788,16 @@ config BR2_RELRO_PARTIAL
>
>  config BR2_RELRO_FULL
>         bool "Full"
> +       depends on BR2_TOOLCHAIN_SUPPORTS_PIE
>         select BR2_PIC_PIE
>         help
>           This option includes the partial configuration, but also marks
>           the GOT as read-only at the cost of initialization time during
>           program loading, i.e every time an executable is started.
>
> +comment "RELRO Full needs a toolchain w/ PIE"
> +       depends on !BR2_TOOLCHAIN_SUPPORTS_PIE
> +
>  endchoice
>
>  comment "RELocation Read Only (RELRO) needs shared libraries"
> --
> 2.23.0
>
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-- 

Matthew Weber | Associate Director Software Engineer | Commercial Avionics

COLLINS AEROSPACE

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matthew.weber at collins.com | collinsaerospace.com



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