RISCV Vector unit disabled by default for new task (was Re: [PATCH v12 17/17] riscv: prctl to enable vector commands)

[Florian Weimer]

* Andrew Waterman:

> This suggests that ld.so, early-stage libc, or possibly both will need
> to make this prctl() call, perhaps by parsing the ELF headers of the
> binary and each library to determine if the V extension is used.

If the string functions use the V extension, it will be enabled
unconditionally.  So I don't see why it's okay for libc to trigger this
alleged UAPI change, when the kernel can't do it by default.

Thanks,
Florian