mirror/freebsd
1
0
Fork 0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-18 10:35:55 +00:00
Code Issues Releases Activity

Fixed bug in handling of COW - the original code was bogus and it was

Browse Source 
only accidental that it worked. Also, don't cache non-managed pages.
This commit is contained in:
David Greenman 1994-02-13 08:29:33 +00:00
parent 211439cc2a
commit 2c194b2e93
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=1151
2 changed files with 34 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
sys/amd64/amd64/pmap.c
View File

@ -35,7 +35,7 @@
* SUCH DAMAGE.
*
* from: @(#)pmap.c 7.7 (Berkeley) 5/12/91
* $Id: pmap.c,v 1.17 1994/02/08 03:07:58 davidg Exp $
* $Id: pmap.c,v 1.18 1994/02/10 03:03:44 davidg Exp $
*/
/*
@ -1096,7 +1096,6 @@ pmap_protect(pmap, sva, eva, prot)
continue;
}
/*
* Page not valid. Again, skip it.
* Should we do this? Or set protection anyway?
@ -1105,15 +1104,20 @@ pmap_protect(pmap, sva, eva, prot)
continue;
i386prot = pte_prot(pmap, prot);
if (va < UPT_MAX_ADDRESS)
i386prot |= PG_RW /*PG_u*/;
if (va < UPT_MIN_ADDRESS)
i386prot |= PG_u;
else if (va < UPT_MAX_ADDRESS)
i386prot |= PG_u | PG_RW;
if (i386prot != pte->pg_prot) {
reqactivate = 1;
pmap_pte_set_prot(pte, i386prot);
}
}
endofloop:
tlbflush();
if (reqactivate)
tlbflush();
}
/*
@ -1217,18 +1221,12 @@ pmap_enter(pmap, va, pa, prot, wired)
pv->pv_next = npv;
}
splx(s);
} else {
cacheable = FALSE;
}
pmap_use_pt(pmap, va, 1);
/*
* Assumption: if it is not part of our managed memory
* then it must be device memory which may be volitile.
*/
if (pmap_initialized) {
checkpv = cacheable = FALSE;
}
/*
* Increment counters
*/
@ -1242,6 +1240,10 @@ pmap_enter(pmap, va, pa, prot, wired)
*/
npte = (pa & PG_FRAME) | pte_prot(pmap, prot) | PG_V;
if (!cacheable) {
npte |= PG_N;
}
/*
* When forking (copy-on-write, etc):
* A process will turn off write permissions for any of its writable
@ -1541,7 +1543,7 @@ pmap_changebit(pa, bit, setem)
/*
* XXX don't write protect pager mappings
*/
if (bit == PG_RO) {
if (!setem && (bit == PG_RW)) {
extern vm_offset_t pager_sva, pager_eva;
if (va >= pager_sva && va < pager_eva)
@ -1625,7 +1627,7 @@ void
pmap_copy_on_write(pa)
vm_offset_t pa;
{
pmap_changebit(pa, PG_RO, TRUE);
pmap_changebit(pa, PG_RW, FALSE);
}

32
sys/i386/i386/pmap.c
View File

@ -35,7 +35,7 @@
* SUCH DAMAGE.
*
* from: @(#)pmap.c 7.7 (Berkeley) 5/12/91
* $Id: pmap.c,v 1.17 1994/02/08 03:07:58 davidg Exp $
* $Id: pmap.c,v 1.18 1994/02/10 03:03:44 davidg Exp $
*/
/*
@ -1096,7 +1096,6 @@ pmap_protect(pmap, sva, eva, prot)
continue;
}
/*
* Page not valid. Again, skip it.
* Should we do this? Or set protection anyway?
@ -1105,15 +1104,20 @@ pmap_protect(pmap, sva, eva, prot)
continue;
i386prot = pte_prot(pmap, prot);
if (va < UPT_MAX_ADDRESS)
i386prot |= PG_RW /*PG_u*/;
if (va < UPT_MIN_ADDRESS)
i386prot |= PG_u;
else if (va < UPT_MAX_ADDRESS)
i386prot |= PG_u | PG_RW;
if (i386prot != pte->pg_prot) {
reqactivate = 1;
pmap_pte_set_prot(pte, i386prot);
}
}
endofloop:
tlbflush();
if (reqactivate)
tlbflush();
}
/*
@ -1217,18 +1221,12 @@ pmap_enter(pmap, va, pa, prot, wired)
pv->pv_next = npv;
}
splx(s);
} else {
cacheable = FALSE;
}
pmap_use_pt(pmap, va, 1);
/*
* Assumption: if it is not part of our managed memory
* then it must be device memory which may be volitile.
*/
if (pmap_initialized) {
checkpv = cacheable = FALSE;
}
/*
* Increment counters
*/
@ -1242,6 +1240,10 @@ pmap_enter(pmap, va, pa, prot, wired)
*/
npte = (pa & PG_FRAME) | pte_prot(pmap, prot) | PG_V;
if (!cacheable) {
npte |= PG_N;
}
/*
* When forking (copy-on-write, etc):
* A process will turn off write permissions for any of its writable
@ -1541,7 +1543,7 @@ pmap_changebit(pa, bit, setem)
/*
* XXX don't write protect pager mappings
*/
if (bit == PG_RO) {
if (!setem && (bit == PG_RW)) {
extern vm_offset_t pager_sva, pager_eva;
if (va >= pager_sva && va < pager_eva)
@ -1625,7 +1627,7 @@ void
pmap_copy_on_write(pa)
vm_offset_t pa;
{
pmap_changebit(pa, PG_RO, TRUE);
pmap_changebit(pa, PG_RW, FALSE);
}