diff options
| author | Kurt Miller <kurt@cvs.openbsd.org> | 2008-11-24 03:19:43 +0000 |
|---|---|---|
| committer | Kurt Miller <kurt@cvs.openbsd.org> | 2008-11-24 03:19:43 +0000 |
| commit | ff062912a0a9a1ff25c0e74f75822f1650db9a0b (patch) | |
| tree | 91a1536f8d25d7fe35129577da4fcb27b2651543 /sys/arch | |
| parent | 182459c1837dd2aeab6973ad0c11d1fb9cc63bb1 (diff) | |
In pmap_write_protect() clear and set the protection bits atomically and
leave the rest alone. Also don't read *spte twice and compare results.
feedback drahn@ okay art@ weingart@
Diffstat (limited to 'sys/arch')
| -rw-r--r-- | sys/arch/i386/i386/pmap.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/sys/arch/i386/i386/pmap.c b/sys/arch/i386/i386/pmap.c index 4a76de411d0..e8ec43d56f5 100644 --- a/sys/arch/i386/i386/pmap.c +++ b/sys/arch/i386/i386/pmap.c @@ -1,4 +1,4 @@ -/* $OpenBSD: pmap.c,v 1.129 2008/11/24 03:13:22 kurt Exp $ */ +/* $OpenBSD: pmap.c,v 1.130 2008/11/24 03:19:42 kurt Exp $ */ /* $NetBSD: pmap.c,v 1.91 2000/06/02 17:46:37 thorpej Exp $ */ /* @@ -2428,7 +2428,7 @@ void pmap_write_protect(struct pmap *pmap, vaddr_t sva, vaddr_t eva, vm_prot_t prot) { - pt_entry_t *ptes, *spte, *epte, npte; + pt_entry_t *ptes, *spte, *epte, npte, opte; vaddr_t blockend; u_int32_t md_prot; vaddr_t va; @@ -2480,11 +2480,14 @@ pmap_write_protect(struct pmap *pmap, vaddr_t sva, vaddr_t eva, if (!pmap_valid_entry(*spte)) /* no mapping? */ continue; - npte = (*spte & ~PG_PROT) | md_prot; + opte = *spte; + npte = (opte & ~PG_PROT) | md_prot; - if (npte != *spte) { + if (npte != opte) { pmap_exec_account(pmap, va, *spte, npte); - i386_atomic_testset_ul(spte, npte); + i386_atomic_clearbits_l(spte, + (~md_prot & opte) & PG_PROT); + i386_atomic_setbits_l(spte, md_prot); } } } |