[PATCH linux dev-6.6 0/2] ARM: prctl: Reject PR_SET_MDWE where not supported

[Andrew Jeffery]

On Tue, 2024-03-26 at 12:49 -0700, Zev Weiss wrote:
> [Re-sending as I forgot to CC the list the first time, apologies for
> the duplication.]
> 
> OpenBMC on AST2400 has been badly broken for some time now due to
> systemd services segfaulting on execve() after calls to
> prctl(PR_SET_MDWE) spuriously succeeded.  The MMU of the ARMv5 CPU in
> the AST2400 cannot meaningfully support MDWE because it lacks distinct
> read & execute page permissions (read implies execute), so these
> patches ensure that the prctl to enable MDWE properly fails on
> hardware where it isn't supported.
> 
> These patches have been posted and approved upstream [0], and while at
> time of writing they haven't yet reached mainline or stable upstream,
> they're on their way and should hopefully get merged soon [1, 2].
> 

Nice, palmetto userspace behaves much better under qemu after applying
these.

Andrew