K 10
svn:author
V 2
br
K 8
svn:date
V 27
2018-07-27T16:13:06.795934Z
K 7
svn:log
V 370
Use SPP (Supervisor Previous Privilege) bit in the sstatus
register to determine if trap is from userspace.

Otherwise if we jump to kernel address from userspace, then
TRAPF_USERMODE failed to detect usermode and then do_ast
triggers a panic "ast in kernel mode".

Reviewed by:	markj@
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D16469

END