[src/trunk]: src/sys/arch/x86/x86 svs_pdir_switch(): Use MOVS to copy the PTES.

[ad <ad%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/aa91c07572a5
branches:  trunk
changeset: 972493:aa91c07572a5
user:      ad <ad%NetBSD.org@localhost>
date:      Wed May 27 19:40:29 2020 +0000

description:
svs_pdir_switch(): Use MOVS to copy the PTES.

diffstat:

 sys/arch/x86/x86/svs.c |  31 +++++++------------------------
 1 files changed, 7 insertions(+), 24 deletions(-)

diffs (67 lines):

diff -r bd34bc93ddf3 -r aa91c07572a5 sys/arch/x86/x86/svs.c
--- a/sys/arch/x86/x86/svs.c    Wed May 27 19:33:40 2020 +0000
+++ b/sys/arch/x86/x86/svs.c    Wed May 27 19:40:29 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: svs.c,v 1.36 2020/05/27 19:15:08 ad Exp $      */
+/*     $NetBSD: svs.c,v 1.37 2020/05/27 19:40:29 ad Exp $      */
 
 /*
  * Copyright (c) 2018-2020 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: svs.c,v 1.36 2020/05/27 19:15:08 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: svs.c,v 1.37 2020/05/27 19:40:29 ad Exp $");
 
 #include "opt_svs.h"
 #include "opt_user_ldt.h"
@@ -682,28 +682,16 @@
        }
 }
 
-static inline pt_entry_t
-svs_pte_atomic_read(struct pmap *pmap, size_t idx)
-{
-       /*
-        * XXX: We don't have a basic atomic_fetch_64 function?
-        */
-       return atomic_cas_64(&pmap->pm_pdir[idx], 666, 666);
-}
-
 /*
- * We may come here with the pmap unlocked. So read its PTEs atomically. If
- * a remote CPU is updating them at the same time, it's not a problem: the
- * remote CPU will call svs_pmap_sync afterwards, and our updirpa will be
- * synchronized properly.
+ * We may come here with the pmap unlocked.  If a remote CPU is updating
+ * them at the same time, it's not a problem: the remote CPU will call
+ * svs_pmap_sync afterwards, and our updirpa will be synchronized properly.
  */
 void
 svs_pdir_switch(struct pmap *pmap)
 {
        struct cpu_info *ci = curcpu();
        struct svs_utls *utls;
-       pt_entry_t pte;
-       size_t i;
 
        KASSERT(kpreempt_disabled());
        KASSERT(pmap != pmap_kernel());
@@ -712,14 +700,9 @@
        utls = (struct svs_utls *)ci->ci_svs_utls;
        utls->kpdirpa = pmap_pdirpa(pmap, 0) | svs_pcid_kcr3;
 
+       /* Copy user slots. */
        mutex_enter(&ci->ci_svs_mtx);
-
-       /* User slots. */
-       for (i = 0; i < PDIR_SLOT_USERLIM; i++) {
-               pte = svs_pte_atomic_read(pmap, i);
-               ci->ci_svs_updir[i] = pte;
-       }
-
+       x86_movs(ci->ci_svs_updir, pmap->pm_pdir, PDIR_SLOT_USERLIM);
        mutex_exit(&ci->ci_svs_mtx);
 
        if (svs_pcid) {