K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2021-10-17T18:50:31.601434Z
K 7
svn:log
V 546
x86: cpufunc: Add rdtsc_ordered()

Add a variant of 'rdtsc()' that performs the ordered version of 'rdtsc'
appropriate for the invoking x86 variant.

Also, expose the 'lfence'-ed and 'mfence'-ed 'rdtsc()' variants needed
by 'rdtsc_ordered()' for general use.

Sponsored by:	Juniper Networks, Inc.
Sponsored by:	Klara, Inc.
Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D31416

(cherry picked from commit 652ae7b11485d9f991ea66a56aa79d4dd9cd1103)

Git Hash:   946f96d13b013963cc11de1eca2ede4c0658fc61
Git Author: adam@fenn.io
END