svn commit: r361232 - head/sys/powerpc/aim

[Justin Hibbits]

Author: jhibbits
Date: Tue May 19 01:06:31 2020
New Revision: 361232
URL: https://svnweb.freebsd.org/changeset/base/361232

Log:
  powerpc/mmu: Don't use the cache instructions to zero pages
  
  A page (even physmem) can be marked as cache-inhibited.  Attempting to use
  'dcbz' to zero a page mapped cache-inhibited triggers an alignment
  exception, which is fatal in kernel.  This was seen when testing hardware
  acceleration with X on POWER9.
  
  At some point in the future, this should be changed to a more straight
  forward zero loop instead of bzero(), and a similar change be made to the
  other pmaps.
  
  Reported by:	pkubaj@

Modified:
  head/sys/powerpc/aim/mmu_radix.c

Modified: head/sys/powerpc/aim/mmu_radix.c
==============================================================================
--- head/sys/powerpc/aim/mmu_radix.c	Tue May 19 01:05:13 2020	(r361231)
+++ head/sys/powerpc/aim/mmu_radix.c	Tue May 19 01:06:31 2020	(r361232)
@@ -909,10 +909,8 @@ static void
 pagezero(vm_offset_t va)
 {
 	va = trunc_page(va);
-	int off;
 
-	for (off = 0; off < PAGE_SIZE; off += cacheline_size)
-		__asm __volatile("dcbz 0,%0" :: "r"(va + off));
+	bzero((void *)va, PAGE_SIZE);
 }
 
 static uint64_t