[src/trunk]: src/sys/arch/arm/arm32 Fix ARM_VECTORS_LOW fallout caused by the...

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

details:   https://anonhg.NetBSD.org/src/rev/57b7c14e489f
branches:  trunk
changeset: 557804:57b7c14e489f
user:      scw <scw%NetBSD.org@localhost>
date:      Sun Jan 18 13:03:50 2004 +0000

description:
Fix ARM_VECTORS_LOW fallout caused by the recent reaper removal.

Just before removing the vector page mapping, switch to the kernel
pmap's L1/vector page mapping so as not to pull the rug out from
under ourselves.

To prevent the stale L1/vector page mapping from being restored by
cpu_switch, replace the relevant fields of the dying process' pcb
with those of lwp0's pcb.

diffstat:

 sys/arch/arm/arm32/pmap.c |  29 +++++++++++++++++++++++++++--
 1 files changed, 27 insertions(+), 2 deletions(-)

diffs (53 lines):

diff -r 29e2f73e7bdc -r 57b7c14e489f sys/arch/arm/arm32/pmap.c
--- a/sys/arch/arm/arm32/pmap.c Sun Jan 18 13:00:05 2004 +0000
+++ b/sys/arch/arm/arm32/pmap.c Sun Jan 18 13:03:50 2004 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.146 2003/11/01 17:35:42 jdolecek Exp $      */
+/*     $NetBSD: pmap.c,v 1.147 2004/01/18 13:03:50 scw Exp $   */
 
 /*
  * Copyright 2003 Wasabi Systems, Inc.
@@ -212,7 +212,7 @@
 #include <machine/param.h>
 #include <arm/arm32/katelib.h>
 
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.146 2003/11/01 17:35:42 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.147 2004/01/18 13:03:50 scw Exp $");
 
 #ifdef PMAP_DEBUG
 
@@ -3195,9 +3195,34 @@
         */
 
        if (vector_page < KERNEL_BASE) {
+               struct pcb *pcb = &lwp0.l_addr->u_pcb;
+
+               if (pmap_is_current(pm)) {
+                       /*
+                        * Frob the L1 entry corresponding to the vector
+                        * page so that it contains the kernel pmap's domain
+                        * number. This will ensure pmap_remove() does not
+                        * pull the current vector page out from under us.
+                        */
+                       disable_interrupts(I32_bit | F32_bit);
+                       *pcb->pcb_pl1vec = pcb->pcb_l1vec;
+                       cpu_domains(pcb->pcb_dacr);
+                       cpu_setttb(pcb->pcb_pagedir);
+                       enable_interrupts(I32_bit | F32_bit);
+               }
+
                /* Remove the vector page mapping */
                pmap_remove(pm, vector_page, vector_page + PAGE_SIZE);
                pmap_update(pm);
+
+               /*
+                * Make sure cpu_switch(), et al, DTRT. This is safe to do
+                * since this process has no remaining mappings of its own.
+                */
+               curpcb->pcb_pl1vec = pcb->pcb_pl1vec;
+               curpcb->pcb_l1vec = pcb->pcb_l1vec;
+               curpcb->pcb_dacr = pcb->pcb_dacr;
+               curpcb->pcb_pagedir = pcb->pcb_pagedir;
        }
 
        LIST_REMOVE(pm, pm_list);