[src/trunk]: src/sys/arch/arm/arm32 Since data_abort_handler() may have to de...

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

details:   https://anonhg.NetBSD.org/src/rev/d988e9a02acd
branches:  trunk
changeset: 555305:d988e9a02acd
user:      scw <scw%NetBSD.org@localhost>
date:      Fri Nov 14 00:21:30 2003 +0000

description:
Since data_abort_handler() may have to decode the instruction at tf->tf_pc
to determine if a fault is read or write, make sure tf->tf_pc is 32-bit
aligned before dereferencing it.

Otherwise, deliver an illegal instruction signal to the process. We don't
support execution of Thumb code at this time.

diffstat:

 sys/arch/arm/arm32/fault.c |  33 +++++++++++++++++++++++++++++++--
 1 files changed, 31 insertions(+), 2 deletions(-)

diffs (54 lines):

diff -r c15e3925e898 -r d988e9a02acd sys/arch/arm/arm32/fault.c
--- a/sys/arch/arm/arm32/fault.c        Thu Nov 13 23:55:20 2003 +0000
+++ b/sys/arch/arm/arm32/fault.c        Fri Nov 14 00:21:30 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fault.c,v 1.39 2003/10/31 16:30:15 scw Exp $   */
+/*     $NetBSD: fault.c,v 1.40 2003/11/14 00:21:30 scw Exp $   */
 
 /*
  * Copyright 2003 Wasabi Systems, Inc.
@@ -81,7 +81,7 @@
 #include "opt_kgdb.h"
 
 #include <sys/types.h>
-__KERNEL_RCSID(0, "$NetBSD: fault.c,v 1.39 2003/10/31 16:30:15 scw Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fault.c,v 1.40 2003/11/14 00:21:30 scw Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -286,6 +286,35 @@
                break;
        }
 
+       /*
+        * Make sure the Program Counter is sane. We could fall foul of
+        * someone executing Thumb code, in which case the PC might not
+        * be word-aligned. This would cause a kernel alignment fault
+        * further down if we have to decode the current instruction.
+        * XXX: It would be nice to be able to support Thumb at some point.
+        */
+       if (__predict_false((tf->tf_pc & 3) != 0)) {
+               if (user) {
+                       /*
+                        * Give the user an illegal instruction signal.
+                        */
+                       /* Deliver a SIGILL to the process */
+                       KSI_INIT_TRAP(&ksi);
+                       ksi.ksi_signo = SIGILL;
+                       ksi.ksi_code = ILL_ILLOPC;
+                       ksi.ksi_addr = (u_int32_t *)(intptr_t) far;
+                       ksi.ksi_trap = fsr;
+                       goto do_trapsignal;
+               }
+
+               /*
+                * The kernel never executes Thumb code.
+                */
+               printf("\ndata_abort_fault: Misaligned Kernel-mode "
+                   "Program Counter\n");
+               dab_fatal(tf, fsr, far, l, NULL);
+       }
+
        va = trunc_page((vaddr_t)far);
 
        /*