svn commit: r250358 - stable/9/sys/amd64/amd64

[Konstantin Belousov]

Author: kib
Date: Wed May  8 10:11:31 2013
New Revision: 250358
URL: http://svnweb.freebsd.org/changeset/base/250358

Log:
  MFC r250152:
  The check to ensure that xstate_bv always has XFEATURE_ENABLED_X87 and
  XFEATURE_ENABLED_SSE bits set is not needed.  CPU correctly handles
  any bitmask which is subset of the enabled bits in %XCR0.
  
  More, CPU instructions XSAVE and XSAVEOPT could write the mask without
  e.g. XFEATURE_ENABLED_SSE, after the VZEROALL.  The check prevents the
  restoration of the otherwise valid FPU save area.

Modified:
  stable/9/sys/amd64/amd64/fpu.c
Directory Properties:
  stable/9/sys/   (props changed)

Modified: stable/9/sys/amd64/amd64/fpu.c
==============================================================================
--- stable/9/sys/amd64/amd64/fpu.c	Wed May  8 09:42:50 2013	(r250357)
+++ stable/9/sys/amd64/amd64/fpu.c	Wed May  8 10:11:31 2013	(r250358)
@@ -743,9 +743,6 @@ fpusetxstate(struct thread *td, char *xf
 	 */
 	if (bv & ~xsave_mask)
 		return (EINVAL);
-	if ((bv & (XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE)) !=
-	    (XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE))
-		return (EINVAL);
 
 	hdr = (struct xstate_hdr *)(get_pcb_user_save_td(td) + 1);