[src/netbsd-6-0]: src/sys/arch Pull up following revision(s) (requested by ma...

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

details:   https://anonhg.NetBSD.org/src/rev/670b45602377
branches:  netbsd-6-0
changeset: 775189:670b45602377
user:      snj <snj%NetBSD.org@localhost>
date:      Sat Mar 25 17:20:07 2017 +0000

description:
Pull up following revision(s) (requested by maxv in ticket #1446):
        sys/arch/amd64/amd64/trap.c: revision 1.94
        sys/arch/i386/i386/trap.c: revision 1.287
Mmh, allow iret to be handled when an #SS fault (T_STKFLT) happens. Even
if the sdm is far from being clear, it appears that iret can trigger an #SS
fault if %ss points to a writable but non-present segment; in which case
the kernel would panic, thinking the fault was internal to it.
In particular, userland can create a broken segment in the ldt with
USER_LDT, update its %ss with setcontext and trigger the panic. I don't
think amd64 is affected since USER_LDT does not exist there, and the
changes on tf_ss seem correct - but I'm still adding T_STKFLT for safety.

diffstat:

 sys/arch/amd64/amd64/trap.c |  5 +++--
 sys/arch/i386/i386/trap.c   |  5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diffs (52 lines):

diff -r a0fcd707ebe7 -r 670b45602377 sys/arch/amd64/amd64/trap.c
--- a/sys/arch/amd64/amd64/trap.c       Wed Mar 08 14:57:26 2017 +0000
+++ b/sys/arch/amd64/amd64/trap.c       Sat Mar 25 17:20:07 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: trap.c,v 1.69.2.1 2012/06/03 21:45:10 jdc Exp $        */
+/*     $NetBSD: trap.c,v 1.69.2.1.4.1 2017/03/25 17:20:07 snj Exp $    */
 
 /*-
  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -68,7 +68,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.69.2.1 2012/06/03 21:45:10 jdc Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.69.2.1.4.1 2017/03/25 17:20:07 snj Exp $");
 
 #include "opt_ddb.h"
 #include "opt_kgdb.h"
@@ -294,6 +294,7 @@
        case T_PROTFLT:
        case T_SEGNPFLT:
        case T_ALIGNFLT:
+       case T_STKFLT:
        case T_TSSFLT:
                if (p == NULL)
                        goto we_re_toast;
diff -r a0fcd707ebe7 -r 670b45602377 sys/arch/i386/i386/trap.c
--- a/sys/arch/i386/i386/trap.c Wed Mar 08 14:57:26 2017 +0000
+++ b/sys/arch/i386/i386/trap.c Sat Mar 25 17:20:07 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: trap.c,v 1.262 2011/09/07 09:24:55 reinoud Exp $       */
+/*     $NetBSD: trap.c,v 1.262.12.1 2017/03/25 17:20:07 snj Exp $      */
 
 /*-
  * Copyright (c) 1998, 2000, 2005, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -68,7 +68,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.262 2011/09/07 09:24:55 reinoud Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.262.12.1 2017/03/25 17:20:07 snj Exp $");
 
 #include "opt_ddb.h"
 #include "opt_kgdb.h"
@@ -405,6 +405,7 @@
 #endif
        case T_SEGNPFLT:
        case T_ALIGNFLT:
+       case T_STKFLT:
        case T_TSSFLT:
                if (p == NULL)
                        goto we_re_toast;