[PATCH] x86: Remove ARCH_CET_LEGACY_BITMAP [BZ #25397]

[Florian Weimer]

* H. J. Lu:

> +  funcp = mmap (NULL, 0x1000, PROT_EXEC | PROT_READ | PROT_WRITE,
> +		MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);

An alternative approach would automatically allocate a legacy bitmap
for RWX mappings under the right circumstances (maybe even looking and
the caller address in mmap).  Have you considered that?

I'm not question the removal of the legacy bitmap as such.  It looks
like the right call.  I just want to collect some thoughts for
posterity.