K 10
svn:author
V 3
mjg
K 8
svn:date
V 27
2018-10-20T17:00:18.961993Z
K 7
svn:log
V 443
amd64: relax constraints in curthread and curpcb

This makes the compiler less likely to reload the content from %gs.

The 'P' modifier drops all synteax prefixes and 'n' constraint treats
input as a known at compilation time immediate integer.

Example reloading victim was spinlock_enter.

Stolen from:	OpenBSD

Reported by:	jtl
Reviewed by:	kib
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D17615

END