[Buildroot] [git commit branch/2021.02.x] Config.in: disable PIC/PIE for Nios2

[Peter Korsgaard]

>>>>> "David" == David Laight <David.Laight at ACULAB.COM> writes:

Hi,

 >> Recently in Buildroot the option BR2_PIC_PIE has been enabled by default along
 >> with other hardening features [1]. Since then the nios2 defconfig
 >> qemu_nios2_10m50_defconfig is failing to boot due to a segfault in init program:

 > You probably just don't want to enable PIE for nios2 at all.

Notice that this commit was about disallowing PIE for nios2.

 > Even switch statement jump tables are problematic in shared objects.
 > (I think the table has to go in .code to ensure it is <16k from
 > the instructions that use it.)
 > The change to gcc certainly broke our use where the code is 'pure'.
 > We only run a few kB of code.

 > It is worth remembering that the nios2 is a simple in-order cpu
 > built from FPGA logic elements.
 > Getting one to run at much over 100MHz is hard.

 > We do use them for embedded code loops, I really can't imagine
 > running Linux on one - probably too slow to be really useful.
 > After all, if you need to run Linux on an fpga there are plently
 > with a small ARM core 'in the corner'.

Yes, I also cannot recommend people using nios2 (or microblaze for that
matter) for Linux systems.

-- 
Bye, Peter Korsgaard