svn commit: r366416 - head/sys/amd64/amd64

[Konstantin Belousov]

Author: kib
Date: Sat Oct  3 23:11:20 2020
New Revision: 366416
URL: https://svnweb.freebsd.org/changeset/base/366416

Log:
  Fix pmap_pti_add_kva() call for doublefault stack page.
  
  After r354889 stack got struct nmi_pcpu at top, which makes IST top
  not page-aligned.  Since pmap_pti_add_kva() truncates/rounds up
  addresses, it erronously entered a page mapped before double fault
  stack into the pti page table.
  
  Sponsored by:	The FreeBSD Foundation
  MFC after:	3 days

Modified:
  head/sys/amd64/amd64/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Sat Oct  3 23:07:09 2020	(r366415)
+++ head/sys/amd64/amd64/pmap.c	Sat Oct  3 23:11:20 2020	(r366416)
@@ -10479,7 +10479,7 @@ pmap_pti_init(void)
 	    sizeof(struct gate_descriptor) * NIDT, false);
 	CPU_FOREACH(i) {
 		/* Doublefault stack IST 1 */
-		va = __pcpu[i].pc_common_tss.tss_ist1;
+		va = __pcpu[i].pc_common_tss.tss_ist1 + sizeof(struct nmi_pcpu);
 		pmap_pti_add_kva_locked(va - PAGE_SIZE, va, false);
 		/* NMI stack IST 2 */
 		va = __pcpu[i].pc_common_tss.tss_ist2 + sizeof(struct nmi_pcpu);