errno/h_errno

[H. Peter Anvin]

Hi,

I'm wondering: is there any reason whatsoever why not to change the 
definition of errno/h_errno to:

__thread int errno __attribute__((tls_model("initial-exec")));

... to bypass a rather unnecessary function call? After all, errno gets 
accessed *all over the place*, and there is no reason why other modules 
should not be able to make use of this. As far as I understand, the 
above should result, for PIC code, in a GOTTPOFF relocation, and a GOT 
entry filled in by the dynamic linker.

The functions __[h_]errno_location can of course remain for 
compatibility reasons.

This would seem to be a trivial optimization, which would even be 
backwards compatible.

Am I missing something fundamental?

Thanks,

	-hpa