On 11/24/2017 12:29 AM, Dave Hansen wrote:

Although weird, the thought here was that pkey_mprotect() callers are
new and should know about the interactions with PROT_EXEC.  They can
also*get*  PROT_EXEC semantics if they want.

The only wart here is if you do:

	mprotect(..., PROT_EXEC); // key 10 is now the PROT_EXEC key

I thought the PROT_EXEC key is always 1?

	pkey_mprotect(..., PROT_EXEC, key=3);

I'm not sure what this does.  We should probably ensure that it returns
an error.

Without protection key support, PROT_EXEC would imply PROT_READ with an 
ordinary mprotect.  I think it makes sense to stick to this behavior. 
It is what I have documented for glibc:

   <https://sourceware.org/ml/libc-alpha/2017-11/msg00841.html>

Thanks,
Florian

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