[src/trunk]: src/sys Exclude the PTE space from KCSAN, since there the same V...

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

details:   https://anonhg.NetBSD.org/src/rev/3d1e1eebf688
branches:  trunk
changeset: 460897:3d1e1eebf688
user:      maxv <maxv%NetBSD.org@localhost>
date:      Fri Nov 08 12:36:10 2019 +0000

description:
Exclude the PTE space from KCSAN, since there the same VA can point to
different PAs.

diffstat:

 sys/arch/amd64/include/csan.h |  11 ++++++++++-
 sys/kern/subr_csan.c          |   6 ++++--
 2 files changed, 14 insertions(+), 3 deletions(-)

diffs (55 lines):

diff -r 7df973774dd8 -r 3d1e1eebf688 sys/arch/amd64/include/csan.h
--- a/sys/arch/amd64/include/csan.h     Fri Nov 08 11:12:09 2019 +0000
+++ b/sys/arch/amd64/include/csan.h     Fri Nov 08 12:36:10 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: csan.h,v 1.2 2019/11/06 06:57:22 maxv Exp $    */
+/*     $NetBSD: csan.h,v 1.3 2019/11/08 12:36:11 maxv Exp $    */
 
 /*
  * Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -30,9 +30,18 @@
  */
 
 #include <sys/ksyms.h>
+#include <uvm/uvm.h>
+#include <amd64/pmap.h>
 #include <x86/cpufunc.h>
 
 static inline bool
+kcsan_md_unsupported(vaddr_t addr)
+{
+       return (addr >= (vaddr_t)PTE_BASE &&
+           addr < ((vaddr_t)PTE_BASE + NBPD_L4));
+}
+
+static inline bool
 kcsan_md_is_avail(void)
 {
        return true;
diff -r 7df973774dd8 -r 3d1e1eebf688 sys/kern/subr_csan.c
--- a/sys/kern/subr_csan.c      Fri Nov 08 11:12:09 2019 +0000
+++ b/sys/kern/subr_csan.c      Fri Nov 08 12:36:10 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_csan.c,v 1.2 2019/11/06 06:57:22 maxv Exp $       */
+/*     $NetBSD: subr_csan.c,v 1.3 2019/11/08 12:36:10 maxv Exp $       */
 
 /*
  * Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_csan.c,v 1.2 2019/11/06 06:57:22 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_csan.c,v 1.3 2019/11/08 12:36:10 maxv Exp $");
 
 #include "opt_kcsan.h"
 
@@ -136,6 +136,8 @@
 
        if (__predict_false(!kcsan_enabled))
                return;
+       if (__predict_false(kcsan_md_unsupported((vaddr_t)addr)))
+               return;
 
        new.addr = addr;
        new.size = size;