svn commit: r366195 - head/sys/arm64/arm64

[Michal Meloun]

Author: mmel
Date: Sun Sep 27 09:27:39 2020
New Revision: 366195
URL: https://svnweb.freebsd.org/changeset/base/366195

Log:
  Reapply r366193 with proper commit log.
  
  Don't map same physical memory multiple times with different cache attributes.
  This is explicitly stated as architectural undefined behavior, leading to
  coherency issues sooner or later.

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

Modified: head/sys/arm64/arm64/locore.S
==============================================================================
--- head/sys/arm64/arm64/locore.S	Sun Sep 27 09:24:31 2020	(r366194)
+++ head/sys/arm64/arm64/locore.S	Sun Sep 27 09:27:39 2020	(r366195)
@@ -498,7 +498,7 @@ common:
 	cbz	x19, 1f
 
 	/* Create the identity mapping for FDT data (2 MiB max) */
-	mov	x7, #(ATTR_S1_nG | ATTR_S1_IDX(VM_MEMATTR_UNCACHEABLE))
+	mov	x7, #(ATTR_S1_nG | ATTR_S1_IDX(VM_MEMATTR_WRITE_BACK))
 	mov	x9, x0
 	mov	x8, x0		/* VA start (== PA start) */
 	mov	x10, #1
@@ -508,7 +508,7 @@ common:
 #endif
 
 	/* Create the VA = PA map */
-	mov	x7, #(ATTR_S1_nG | ATTR_S1_IDX(VM_MEMATTR_UNCACHEABLE))
+	mov	x7, #(ATTR_S1_nG | ATTR_S1_IDX(VM_MEMATTR_WRITE_BACK))
 	mov	x9, x27
 	mov	x8, x9		/* VA start (== PA start) */
 	mov	x10, #1