svn commit: r287532 - head/sys/arm64/arm64

[Andrew Turner]

Author: andrew
Date: Mon Sep  7 10:13:14 2015
New Revision: 287532
URL: https://svnweb.freebsd.org/changeset/base/287532

Log:
  When dropping to EL1 ensure we have written to all special registers by
  moving the instruction barrier to just before we drop exception level.
  
  Sponsored by:	ABT Systems Ltd

Modified:
  head/sys/arm64/arm64/locore.S

Modified: head/sys/arm64/arm64/locore.S
==============================================================================
--- head/sys/arm64/arm64/locore.S	Mon Sep  7 07:22:35 2015	(r287531)
+++ head/sys/arm64/arm64/locore.S	Mon Sep  7 10:13:14 2015	(r287532)
@@ -246,11 +246,11 @@ drop_to_el1:
 	mrs	x2, icc_sre_el2
 	orr	x2, x2, #ICC_SRE_EL2_EN	/* Enable access from insecure EL1 */
 	msr	icc_sre_el2, x2
-	isb
 2:
 
 	/* Set the address to return to our return address */
 	msr	elr_el2, x30
+	isb
 
 	eret