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pmap_enter: 

- when overwriting an existing mapping for the same page,
  inherit R/M bits so that they won't be lost.
- xen: don't leave ptp on error.
This commit is contained in:
yamt 2008-01-20 22:41:55 +00:00
parent f093a1dc3b
commit 569f933f28
1 changed files with 35 additions and 15 deletions
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50
sys/arch/x86/x86/pmap.c
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@ -1,4 +1,4 @@
/* $NetBSD: pmap.c,v 1.40 2008/01/20 21:56:11 yamt Exp $ */
/* $NetBSD: pmap.c,v 1.41 2008/01/20 22:41:55 yamt Exp $ */
/*
* Copyright (c) 2007 Manuel Bouyer.
@ -154,7 +154,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.40 2008/01/20 21:56:11 yamt Exp $");
__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.41 2008/01/20 22:41:55 yamt Exp $");
#include "opt_user_ldt.h"
#include "opt_lockdebug.h"
@ -3842,21 +3842,41 @@ pmap_enter(struct pmap *pmap, vaddr_t va, paddr_t pa, vm_prot_t prot,
*/
ptep = &ptes[pl1_i(va)];
#ifdef XEN
if (domid != DOMID_SELF) {
int s = splvm();
do {
opte = *ptep;
error = xpq_update_foreign((pt_entry_t *)vtomach((vaddr_t)ptep),
npte, domid);
splx(s);
if (error) {
pmap_unmap_ptes(pmap, pmap2);
goto out;
/*
* if the same page, inherit PG_U and PG_M.
*/
if (((opte ^ npte) & (PG_FRAME | PG_V)) == 0) {
npte |= opte & (PG_U | PG_M);
}
} else
#endif /* XEN */
opte = pmap_pte_testset(ptep, npte); /* zap! */
#if defined(XEN)
if (domid != DOMID_SELF) {
/* pmap_pte_cas with error handling */
int s = splvm();
if (opte != *ptep) {
splx(s);
continue;
}
error = xpq_update_foreign(
(pt_entry_t *)vtomach((vaddr_t)ptep), npte, domid);
splx(s);
if (error) {
struct vm_page *empty_ptps = NULL;
if (ptp != NULL && ptp->wire_count <= 1) {
pmap_free_ptp(pmap, ptp, va, ptes, pdes,
&empty_ptps);
}
pmap_unmap_ptes(pmap, pmap2);
pmap_free_empty_ptps(empty_ptps);
goto out;
}
break;
}
#endif /* defined(XEN) */
} while (pmap_pte_cas(ptep, opte, npte) != opte);
/*
* update statistics and PTP's reference count.