[src/trunk]: src/sys/arch/usermode/usermode Implement trap recursion detectio...

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

details:   https://anonhg.NetBSD.org/src/rev/6c263bf1fcb8
branches:  trunk
changeset: 768813:6c263bf1fcb8
user:      reinoud <reinoud%NetBSD.org@localhost>
date:      Sat Aug 27 18:01:37 2011 +0000

description:
Implement trap recursion detection and fix small one-off error in range
checks for kernel space

diffstat:

 sys/arch/usermode/usermode/trap.c |  15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diffs (56 lines):

diff -r 826bbe8dc3e8 -r 6c263bf1fcb8 sys/arch/usermode/usermode/trap.c
--- a/sys/arch/usermode/usermode/trap.c Sat Aug 27 17:59:24 2011 +0000
+++ b/sys/arch/usermode/usermode/trap.c Sat Aug 27 18:01:37 2011 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: trap.c,v 1.6 2011/08/25 19:06:03 reinoud Exp $ */
+/* $NetBSD: trap.c,v 1.7 2011/08/27 18:01:37 reinoud Exp $ */
 
 /*-
  * Copyright (c) 2011 Reinoud Zandijk <reinoud%netbsd.org@localhost>
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.6 2011/08/25 19:06:03 reinoud Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.7 2011/08/27 18:01:37 reinoud Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -83,8 +83,12 @@
        vaddr_t va;
        vaddr_t onfault;
        int kmem, rv;
+       static volatile int recurse = 0;
 
+       recurse++;
        aprint_debug("trap\n");
+       if (recurse > 1)
+               printf("enter trap recursion level %d\n", recurse);
        if ((info->si_signo == SIGSEGV) || (info->si_signo == SIGBUS)) {
                l = curlwp;
                p = l->l_proc;
@@ -121,7 +125,7 @@
 
                kmem = 1;
                vm_map = kernel_map;
-               if ((va >= VM_MIN_ADDRESS) && (va <= VM_MAXUSER_ADDRESS)) {
+               if ((va >= VM_MIN_ADDRESS) && (va < VM_MAXUSER_ADDRESS)) {
                        kmem = 0;
                        vm_map = &vm->vm_map;
                }
@@ -146,11 +150,14 @@
                                memset(tf, 0, sizeof(struct trapframe));
                                tf->tf_pc = onfault;
                                tf->tf_out[0] = (rv == EACCES) ? EFAULT : rv;
+                               recurse--;
                                return;
                        }
                        panic("should deliver a trap to the process");
                }
-
+               if (recurse > 1)
+                       printf("leaving trap recursion level %d\n", recurse);
+               recurse--;
        }
 }