Fix the following problem:

When creating new processes (or performing exec), the new page
directory is initialized too early.  The kernel might grow before
p_vmspace is initialized for the new process.  Since pmap_growkernel
doesn't yet know about the new page directory, it isn't updated, and
subsequent use causes a failure.

The fix is (1) to clear p_vmspace early, to stop pmap_growkernel
from stomping on memory, and (2) to defer part of the initialization
of new page directories until p_vmspace is initialized.

PR:		kern/12378
Submitted by:	tegge
Reviewed by:	dfr
This commit is contained in:
alc 1999-07-21 18:02:27 +00:00
parent 97ef87606c
commit fbaba2d628
7 changed files with 55 additions and 16 deletions

View File

@ -43,7 +43,7 @@
* from: @(#)pmap.c 7.7 (Berkeley) 5/12/91
* from: i386 Id: pmap.c,v 1.193 1998/04/19 15:22:48 bde Exp
* with some ideas from NetBSD's alpha pmap
* $Id: pmap.c,v 1.26 1999/06/10 20:40:55 dt Exp $
* $Id: pmap.c,v 1.27 1999/06/28 09:38:09 peter Exp $
*/
/*
@ -1272,9 +1272,6 @@ pmap_pinit(pmap)
if ((lev1pg->flags & PG_ZERO) == 0)
bzero(pmap->pm_lev1, PAGE_SIZE);
/* wire in kernel global address entries */
/* XXX copies current process, does not fill in MPPTDI */
bcopy(PTlev1 + K1SEGLEV1I, pmap->pm_lev1 + K1SEGLEV1I, nklev2 * PTESIZE);
/* install self-referential address mapping entry (not PG_ASM) */
pmap->pm_lev1[PTLEV1I] = pmap_phys_to_pte(VM_PAGE_TO_PHYS(lev1pg))
@ -1290,6 +1287,19 @@ pmap_pinit(pmap)
bzero(&pmap->pm_stats, sizeof pmap->pm_stats);
}
/*
* Wire in kernel global address entries. To avoid a race condition
* between pmap initialization and pmap_growkernel, this procedure
* should be called after the vmspace is attached to the process
* but before this pmap is activated.
*/
void
pmap_pinit2(pmap)
struct pmap *pmap;
{
bcopy(PTlev1 + K1SEGLEV1I, pmap->pm_lev1 + K1SEGLEV1I, nklev2 * PTESIZE);
}
static int
pmap_release_free_page(pmap_t pmap, vm_page_t p)
{

View File

@ -39,7 +39,7 @@
* SUCH DAMAGE.
*
* from: @(#)pmap.c 7.7 (Berkeley) 5/12/91
* $Id: pmap.c,v 1.240 1999/06/23 21:47:21 luoqi Exp $
* $Id: pmap.c,v 1.241 1999/07/08 06:05:49 mckusick Exp $
*/
/*
@ -1172,9 +1172,6 @@ pmap_pinit(pmap)
if ((ptdpg->flags & PG_ZERO) == 0)
bzero(pmap->pm_pdir, PAGE_SIZE);
/* wire in kernel global address entries */
/* XXX copies current process, does not fill in MPPTDI */
bcopy(PTD + KPTDI, pmap->pm_pdir + KPTDI, nkpt * PTESIZE);
#ifdef SMP
pmap->pm_pdir[MPPTDI] = PTD[MPPTDI];
#endif
@ -1190,6 +1187,20 @@ pmap_pinit(pmap)
bzero(&pmap->pm_stats, sizeof pmap->pm_stats);
}
/*
* Wire in kernel global address entries. To avoid a race condition
* between pmap initialization and pmap_growkernel, this procedure
* should be called after the vmspace is attached to the process
* but before this pmap is activated.
*/
void
pmap_pinit2(pmap)
struct pmap *pmap;
{
/* XXX copies current process, does not fill in MPPTDI */
bcopy(PTD + KPTDI, pmap->pm_pdir + KPTDI, nkpt * PTESIZE);
}
static int
pmap_release_free_page(pmap, p)
struct pmap *pmap;

View File

@ -39,7 +39,7 @@
* SUCH DAMAGE.
*
* from: @(#)pmap.c 7.7 (Berkeley) 5/12/91
* $Id: pmap.c,v 1.240 1999/06/23 21:47:21 luoqi Exp $
* $Id: pmap.c,v 1.241 1999/07/08 06:05:49 mckusick Exp $
*/
/*
@ -1172,9 +1172,6 @@ pmap_pinit(pmap)
if ((ptdpg->flags & PG_ZERO) == 0)
bzero(pmap->pm_pdir, PAGE_SIZE);
/* wire in kernel global address entries */
/* XXX copies current process, does not fill in MPPTDI */
bcopy(PTD + KPTDI, pmap->pm_pdir + KPTDI, nkpt * PTESIZE);
#ifdef SMP
pmap->pm_pdir[MPPTDI] = PTD[MPPTDI];
#endif
@ -1190,6 +1187,20 @@ pmap_pinit(pmap)
bzero(&pmap->pm_stats, sizeof pmap->pm_stats);
}
/*
* Wire in kernel global address entries. To avoid a race condition
* between pmap initialization and pmap_growkernel, this procedure
* should be called after the vmspace is attached to the process
* but before this pmap is activated.
*/
void
pmap_pinit2(pmap)
struct pmap *pmap;
{
/* XXX copies current process, does not fill in MPPTDI */
bcopy(PTD + KPTDI, pmap->pm_pdir + KPTDI, nkpt * PTESIZE);
}
static int
pmap_release_free_page(pmap, p)
struct pmap *pmap;

View File

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)kern_fork.c 8.6 (Berkeley) 4/8/94
* $Id: kern_fork.c,v 1.62 1999/06/30 15:33:34 peter Exp $
* $Id: kern_fork.c,v 1.63 1999/07/03 20:58:44 peter Exp $
*/
#include "opt_ktrace.h"
@ -249,6 +249,8 @@ fork1(p1, flags, procp)
newproc->p_wakeup = 0;
newproc->p_vmspace = NULL;
/*
* Find an unused process ID. We remember a range of unused IDs
* ready to use (from nextpid+1 through pidchecked-1).

View File

@ -61,7 +61,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: pmap.h,v 1.29 1999/04/05 19:38:29 julian Exp $
* $Id: pmap.h,v 1.30 1999/04/23 20:29:57 dt Exp $
*/
/*
@ -121,6 +121,7 @@ void pmap_pageable __P((pmap_t, vm_offset_t, vm_offset_t,
vm_offset_t pmap_phys_address __P((int));
void pmap_pinit __P((pmap_t));
void pmap_pinit0 __P((pmap_t));
void pmap_pinit2 __P((pmap_t));
void pmap_protect __P((pmap_t, vm_offset_t, vm_offset_t,
vm_prot_t));
void pmap_qenter __P((vm_offset_t, vm_page_t *, int));

View File

@ -59,7 +59,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: vm_glue.c,v 1.85 1999/04/06 03:11:34 peter Exp $
* $Id: vm_glue.c,v 1.86 1999/06/19 18:42:49 alc Exp $
*/
#include "opt_rlimit.h"
@ -226,6 +226,8 @@ vm_fork(p1, p2, flags)
if ((flags & RFMEM) == 0) {
p2->p_vmspace = vmspace_fork(p1->p_vmspace);
pmap_pinit2(vmspace_pmap(p2->p_vmspace));
if (p1->p_vmspace->vm_shm)
shmfork(p1, p2);
}

View File

@ -61,7 +61,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: vm_map.c,v 1.171 1999/07/01 19:53:41 peter Exp $
* $Id: vm_map.c,v 1.172 1999/07/11 18:30:31 alc Exp $
*/
/*
@ -2351,6 +2351,7 @@ vmspace_exec(struct proc *p) {
*/
vmspace_free(oldvmspace);
p->p_vmspace = newvmspace;
pmap_pinit2(vmspace_pmap(newvmspace));
if (p == curproc)
pmap_activate(p);
}
@ -2370,6 +2371,7 @@ vmspace_unshare(struct proc *p) {
newvmspace = vmspace_fork(oldvmspace);
vmspace_free(oldvmspace);
p->p_vmspace = newvmspace;
pmap_pinit2(vmspace_pmap(newvmspace));
if (p == curproc)
pmap_activate(p);
}