Rewrite how mod/ref emulation is done. In particular, make
modified attribute checking actually work. Previously, a page could be reported as modified even if it wasn't! This is very bad, and e.g. caused the VM system to attempt to "clean" pages of read-only files. Only lip-services is paid to referenced attribute emulation. This could be improved.
This commit is contained in:
thorpej
parent
dda0d50982
commit
ef2315d256
|
|
@ -1,4 +1,4 @@
|
|||
/* $NetBSD: pmap.h,v 1.6 2000/09/28 14:03:38 is Exp $ */
|
||||
/* $NetBSD: pmap.h,v 1.7 2001/02/02 02:28:18 thorpej Exp $ */
|
||||
|
||||
/*
|
||||
* Copyright (c) 1997 Charles D. Cranor and Washington University.
|
||||
|
|
@ -279,6 +279,10 @@ struct pv_head {
|
|||
struct pv_entry *pvh_list; /* head of list (locked by pvh_lock) */
|
||||
};
|
||||
|
||||
/* These are kept in the vm_physseg array. */
|
||||
#define PGA_REFERENCED 0x01 /* page is referenced */
|
||||
#define PGA_MODIFIED 0x02 /* page is modified */
|
||||
|
||||
struct pv_entry { /* locked by its list's pvh_lock */
|
||||
struct pv_entry *pv_next; /* next entry */
|
||||
struct pmap *pv_pmap; /* the pmap */
|
||||
|
|
@ -364,15 +368,10 @@ extern int pmap_pg_g; /* do we support PG_G? */
|
|||
#define pmap_update() tlbflush()
|
||||
#endif
|
||||
|
||||
#define pmap_clear_modify(pg) pmap_change_attrs(pg, 0, PG_M)
|
||||
#define pmap_clear_reference(pg) pmap_change_attrs(pg, 0, PG_U)
|
||||
#define pmap_is_referenced(pg) pmap_test_attrs(pg, PGA_REFERENCED)
|
||||
#define pmap_is_modified(pg) pmap_test_attrs(pg, PGA_MODIFIED)
|
||||
|
||||
#define pmap_copy(DP,SP,D,L,S) pmap_transfer(DP,SP,D,L,S, FALSE)
|
||||
#define pmap_is_modified(pg) pmap_test_attrs(pg, PG_M)
|
||||
#ifdef notyet
|
||||
#define pmap_is_referenced(pg) pmap_test_attrs(pg, PG_U)
|
||||
#else
|
||||
#define pmap_is_referenced(pg) 1
|
||||
#endif
|
||||
#define pmap_move(DP,SP,D,L,S) pmap_transfer(DP,SP,D,L,S, TRUE)
|
||||
#define pmap_phys_address(ppn) sh3_ptob(ppn)
|
||||
#define pmap_valid_entry(E) ((E) & PG_V) /* is PDE or PTE valid? */
|
||||
|
|
@ -386,7 +385,6 @@ void pmap_activate __P((struct proc *));
|
|||
void pmap_bootstrap __P((vaddr_t));
|
||||
boolean_t pmap_change_attrs __P((struct vm_page *, int, int));
|
||||
void pmap_deactivate __P((struct proc *));
|
||||
static void pmap_page_protect __P((struct vm_page *, vm_prot_t));
|
||||
void pmap_page_remove __P((struct vm_page *));
|
||||
static void pmap_protect __P((struct pmap *, vaddr_t,
|
||||
vaddr_t, vm_prot_t));
|
||||
|
|
@ -459,29 +457,6 @@ pmap_update_2pg(va, vb)
|
|||
#endif
|
||||
}
|
||||
|
||||
/*
|
||||
* pmap_page_protect: change the protection of all recorded mappings
|
||||
* of a managed page
|
||||
*
|
||||
* => this function is a frontend for pmap_page_remove/pmap_change_attrs
|
||||
* => we only have to worry about making the page more protected.
|
||||
* unprotecting a page is done on-demand at fault time.
|
||||
*/
|
||||
|
||||
__inline static void
|
||||
pmap_page_protect(pg, prot)
|
||||
struct vm_page *pg;
|
||||
vm_prot_t prot;
|
||||
{
|
||||
if ((prot & VM_PROT_WRITE) == 0) {
|
||||
if (prot & (VM_PROT_READ|VM_PROT_EXECUTE)) {
|
||||
(void) pmap_change_attrs(pg, PG_RO, PG_RW);
|
||||
} else {
|
||||
pmap_page_remove(pg);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* pmap_protect: change the protection of pages in a pmap
|
||||
*
|
||||
|
|
|
|||
|
|
@ -1,4 +1,4 @@
|
|||
/* $NetBSD: pmap.c,v 1.13 2001/01/14 03:25:46 thorpej Exp $ */
|
||||
/* $NetBSD: pmap.c,v 1.14 2001/02/02 02:28:18 thorpej Exp $ */
|
||||
|
||||
/*
|
||||
* Copyright (c) 1997 Charles D. Cranor and Washington University.
|
||||
|
|
@ -395,6 +395,8 @@ static void pmap_unmap_ptes __P((struct pmap *));
|
|||
|
||||
void pmap_pinit __P((pmap_t));
|
||||
void pmap_release __P((pmap_t));
|
||||
void pmap_changebit(struct pv_head *, pt_entry_t,
|
||||
pt_entry_t);
|
||||
|
||||
/*
|
||||
* p m a p i n l i n e h e l p e r f u n c t i o n s
|
||||
|
|
@ -2318,7 +2320,7 @@ pmap_page_remove(pg)
|
|||
/*
|
||||
* pmap_test_attrs: test a page's attributes
|
||||
*
|
||||
* => we set pv_head => pmap locking
|
||||
* => no need for any locking here
|
||||
*/
|
||||
|
||||
boolean_t
|
||||
|
|
@ -2326,11 +2328,7 @@ pmap_test_attrs(pg, testbits)
|
|||
struct vm_page *pg;
|
||||
int testbits;
|
||||
{
|
||||
int bank, off;
|
||||
char *myattrs;
|
||||
struct pv_head *pvh;
|
||||
struct pv_entry *pve;
|
||||
pt_entry_t *ptes, pte;
|
||||
int bank, off, attr;
|
||||
|
||||
/* XXX: vm_page should either contain pv_head or have a pointer to it */
|
||||
bank = vm_physseg_find(atop(VM_PAGE_TO_PHYS(pg)), &off);
|
||||
|
|
@ -2339,67 +2337,29 @@ pmap_test_attrs(pg, testbits)
|
|||
return(FALSE);
|
||||
}
|
||||
|
||||
/*
|
||||
* before locking: see if attributes are already set and if so,
|
||||
* return!
|
||||
*/
|
||||
attr = vm_physmem[bank].pmseg.attrs[off];
|
||||
|
||||
myattrs = &vm_physmem[bank].pmseg.attrs[off];
|
||||
if (*myattrs & testbits)
|
||||
return(TRUE);
|
||||
|
||||
/* test to see if there is a list before bothering to lock */
|
||||
pvh = &vm_physmem[bank].pmseg.pvhead[off];
|
||||
if (pvh->pvh_list == NULL) {
|
||||
return(FALSE);
|
||||
}
|
||||
|
||||
/* nope, gonna have to do it the hard way */
|
||||
PMAP_HEAD_TO_MAP_LOCK();
|
||||
/* XXX: needed if we hold head->map lock? */
|
||||
simple_lock(&pvh->pvh_lock);
|
||||
|
||||
for (pve = pvh->pvh_list; pve != NULL && (*myattrs & testbits) == 0;
|
||||
pve = pve->pv_next) {
|
||||
ptes = pmap_map_ptes(pve->pv_pmap);
|
||||
pte = ptes[sh3_btop(pve->pv_va)];
|
||||
pmap_unmap_ptes(pve->pv_pmap);
|
||||
*myattrs |= pte;
|
||||
return ((attr & testbits) != 0 ? TRUE : FALSE);
|
||||
}
|
||||
|
||||
/*
|
||||
* note that we will exit the for loop with a non-null pve if
|
||||
* we have found the bits we are testing for.
|
||||
*/
|
||||
|
||||
simple_unlock(&pvh->pvh_lock);
|
||||
PMAP_HEAD_TO_MAP_UNLOCK();
|
||||
return((*myattrs & testbits) != 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* pmap_change_attrs: change a page's attributes
|
||||
* pmap_clear_modify: clear the "modified" attribute on a page.
|
||||
*
|
||||
* => we set pv_head => pmap locking
|
||||
* => we return TRUE if we cleared one of the bits we were asked to
|
||||
* => we return TRUE if the page was marked "modified".
|
||||
*/
|
||||
|
||||
boolean_t
|
||||
pmap_change_attrs(pg, setbits, clearbits)
|
||||
struct vm_page *pg;
|
||||
int setbits, clearbits;
|
||||
pmap_clear_modify(vm_page_t pg)
|
||||
{
|
||||
u_int32_t result;
|
||||
int bank, off;
|
||||
struct pv_head *pvh;
|
||||
struct pv_entry *pve;
|
||||
pt_entry_t *ptes, npte;
|
||||
char *myattrs;
|
||||
boolean_t rv;
|
||||
|
||||
/* XXX: vm_page should either contain pv_head or have a pointer to it */
|
||||
bank = vm_physseg_find(atop(VM_PAGE_TO_PHYS(pg)), &off);
|
||||
if (bank == -1) {
|
||||
printf("pmap_change_attrs: unmanaged page?\n");
|
||||
printf("pmap_clear_modify: unmanged page?\n");
|
||||
return (FALSE);
|
||||
}
|
||||
|
||||
|
|
@ -2408,24 +2368,87 @@ pmap_change_attrs(pg, setbits, clearbits)
|
|||
/* XXX: needed if we hold head->map lock? */
|
||||
simple_lock(&pvh->pvh_lock);
|
||||
|
||||
myattrs = &vm_physmem[bank].pmseg.attrs[off];
|
||||
result = *myattrs & clearbits;
|
||||
*myattrs = (*myattrs | setbits) & ~clearbits;
|
||||
if (vm_physmem[bank].pmseg.attrs[off] & PGA_MODIFIED) {
|
||||
rv = TRUE;
|
||||
pmap_changebit(pvh, 0, ~PG_M);
|
||||
vm_physmem[bank].pmseg.attrs[off] &= ~PGA_MODIFIED;
|
||||
} else
|
||||
rv = FALSE;
|
||||
|
||||
simple_unlock(&pvh->pvh_lock);
|
||||
PMAP_HEAD_TO_MAP_UNLOCK();
|
||||
|
||||
return (rv);
|
||||
}
|
||||
|
||||
/*
|
||||
* pmap_clear_reference: clear the "referenced" attribute on a page.
|
||||
*
|
||||
* => we set pv_head => pmap locking
|
||||
* => we return TRUE if the page was marked "modified".
|
||||
* => XXX Note, referenced emulation isn't complete.
|
||||
*/
|
||||
|
||||
boolean_t
|
||||
pmap_clear_reference(vm_page_t pg)
|
||||
{
|
||||
int bank, off;
|
||||
struct pv_head *pvh;
|
||||
boolean_t rv;
|
||||
|
||||
/* XXX: vm_page should either contain pv_head or have a pointer to it */
|
||||
bank = vm_physseg_find(atop(VM_PAGE_TO_PHYS(pg)), &off);
|
||||
if (bank == -1) {
|
||||
printf("pmap_clear_modify: unmanged page?\n");
|
||||
return (FALSE);
|
||||
}
|
||||
|
||||
PMAP_HEAD_TO_MAP_LOCK();
|
||||
pvh = &vm_physmem[bank].pmseg.pvhead[off];
|
||||
/* XXX: needed if we hold head->map lock? */
|
||||
simple_lock(&pvh->pvh_lock);
|
||||
|
||||
if (vm_physmem[bank].pmseg.attrs[off] & PGA_REFERENCED) {
|
||||
rv = TRUE;
|
||||
#if 0 /* XXX notyet */
|
||||
pmap_changebit(pvh, 0, ~PG_V);
|
||||
#endif
|
||||
vm_physmem[bank].pmseg.attrs[off] &= ~PGA_REFERENCED;
|
||||
} else
|
||||
rv = FALSE;
|
||||
|
||||
simple_unlock(&pvh->pvh_lock);
|
||||
PMAP_HEAD_TO_MAP_UNLOCK();
|
||||
|
||||
return (rv);
|
||||
}
|
||||
|
||||
/*
|
||||
* pmap_changebit: set or clear the specified PTEL bits for all
|
||||
* mappings on the specified page.
|
||||
*
|
||||
* => We expect the pv_head -> map lock to be held
|
||||
*/
|
||||
|
||||
void
|
||||
pmap_changebit(struct pv_head *pvh, pt_entry_t set, pt_entry_t mask)
|
||||
{
|
||||
struct pv_entry *pve;
|
||||
pt_entry_t *ptes, npte;
|
||||
|
||||
for (pve = pvh->pvh_list; pve != NULL; pve = pve->pv_next) {
|
||||
#ifdef DIAGNOSTIC
|
||||
if (pve->pv_va >= uvm.pager_sva && pve->pv_va < uvm.pager_eva) {
|
||||
printf("pmap_change_attrs: found pager VA on pv_list\n");
|
||||
/*
|
||||
* XXX Don't write protect pager mappings.
|
||||
*/
|
||||
if (pve->pv_pmap == pmap_kernel() &&
|
||||
/* XXX */ (mask == ~(PG_RW))) {
|
||||
if (pve->pv_va >= uvm.pager_sva &&
|
||||
pve->pv_va < uvm.pager_eva)
|
||||
continue;
|
||||
}
|
||||
if (!pmap_valid_entry(pve->pv_pmap->pm_pdir[pdei(pve->pv_va)]))
|
||||
panic("pmap_change_attrs: mapping without PTP "
|
||||
"detected");
|
||||
#endif
|
||||
|
||||
ptes = pmap_map_ptes(pve->pv_pmap); /* locks pmap */
|
||||
npte = ptes[sh3_btop(pve->pv_va)];
|
||||
result |= (npte & clearbits);
|
||||
npte = (npte | setbits) & ~clearbits;
|
||||
npte = (ptes[sh3_btop(pve->pv_va)] | set) & mask;
|
||||
if (ptes[sh3_btop(pve->pv_va)] != npte) {
|
||||
ptes[sh3_btop(pve->pv_va)] = npte; /* zap! */
|
||||
|
||||
|
|
@ -2435,11 +2458,6 @@ pmap_change_attrs(pg, setbits, clearbits)
|
|||
}
|
||||
pmap_unmap_ptes(pve->pv_pmap); /* unlocks pmap */
|
||||
}
|
||||
|
||||
simple_unlock(&pvh->pvh_lock);
|
||||
PMAP_HEAD_TO_MAP_UNLOCK();
|
||||
|
||||
return(result != 0);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -2449,10 +2467,37 @@ pmap_change_attrs(pg, setbits, clearbits)
|
|||
/*
|
||||
* pmap_page_protect: change the protection of all recorded mappings
|
||||
* of a managed page
|
||||
*
|
||||
* => NOTE: this is an inline function in pmap.h
|
||||
*/
|
||||
|
||||
void
|
||||
pmap_page_protect(vm_page_t pg, vm_prot_t prot)
|
||||
{
|
||||
int bank, off;
|
||||
struct pv_head *pvh;
|
||||
|
||||
if ((prot & VM_PROT_WRITE) == 0) {
|
||||
if (prot & VM_PROT_ALL) {
|
||||
bank = vm_physseg_find(atop(VM_PAGE_TO_PHYS(pg)), &off);
|
||||
if (bank == -1) {
|
||||
printf("pmap_page_protect: unmanged page?\n");
|
||||
return;
|
||||
}
|
||||
|
||||
PMAP_HEAD_TO_MAP_LOCK();
|
||||
pvh = &vm_physmem[bank].pmseg.pvhead[off];
|
||||
/* XXX: needed if we hold head->map lock? */
|
||||
simple_lock(&pvh->pvh_lock);
|
||||
|
||||
pmap_changebit(pvh, 0, ~PG_RW);
|
||||
|
||||
simple_unlock(&pvh->pvh_lock);
|
||||
PMAP_HEAD_TO_MAP_UNLOCK();
|
||||
} else {
|
||||
pmap_page_remove(pg);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/* see pmap.h */
|
||||
|
||||
/*
|
||||
|
|
@ -3270,20 +3315,49 @@ enter_now:
|
|||
*/
|
||||
|
||||
npte = pa | protection_codes[prot] | PG_V | PG_N | PG_4K;
|
||||
if (pvh)
|
||||
if (pvh) {
|
||||
/*
|
||||
* Page is managed. Deal with modified/referenced
|
||||
* attributes.
|
||||
*
|
||||
* XXX Referenced emulation could be improved.
|
||||
*/
|
||||
int attrs;
|
||||
|
||||
simple_lock(&pvh->pvh_lock);
|
||||
if (flags & VM_PROT_WRITE)
|
||||
vm_physmem[bank].pmseg.attrs[off] |=
|
||||
(PGA_REFERENCED|PGA_MODIFIED);
|
||||
else if (flags & VM_PROT_ALL)
|
||||
vm_physmem[bank].pmseg.attrs[off] |=
|
||||
PGA_REFERENCED;
|
||||
attrs = vm_physmem[bank].pmseg.attrs[off];
|
||||
simple_unlock(&pvh->pvh_lock);
|
||||
|
||||
/*
|
||||
* If the page is dirty, don't fault on write.
|
||||
*/
|
||||
if (attrs & PGA_MODIFIED)
|
||||
npte |= PG_M;
|
||||
|
||||
/*
|
||||
* Mapping was entered on the PV list.
|
||||
*/
|
||||
npte |= PG_PVLIST;
|
||||
} else {
|
||||
/*
|
||||
* Non-managed page -- mark it "dirty" anyway.
|
||||
*/
|
||||
npte |= PG_M;
|
||||
}
|
||||
if (wired)
|
||||
npte |= PG_W;
|
||||
if (va < VM_MAXUSER_ADDRESS)
|
||||
npte |= PG_u;
|
||||
else if (va < VM_MAX_ADDRESS)
|
||||
npte |= (PG_u | PG_RW); /* XXXCDC: no longer needed? */
|
||||
if (pmap == pmap_kernel()) {
|
||||
if (pmap == pmap_kernel())
|
||||
npte |= pmap_pg_g;
|
||||
npte |= PG_M; /* XXX */
|
||||
}
|
||||
if (flags & VM_PROT_WRITE)
|
||||
npte |= PG_M;
|
||||
|
||||
ptes[sh3_btop(va)] = npte; /* zap! */
|
||||
|
||||
|
|
@ -3446,23 +3520,52 @@ pmap_emulate_reference(p, va, user, write)
|
|||
vaddr_t va;
|
||||
int user, write;
|
||||
{
|
||||
struct pmap *pmap = p->p_vmspace->vm_map.pmap;
|
||||
pt_entry_t *ptes;
|
||||
struct pmap *pmap;
|
||||
pt_entry_t *ptes, pte;
|
||||
paddr_t pa;
|
||||
struct pv_head *pvh;
|
||||
int bank, off;
|
||||
|
||||
/*
|
||||
* Convert process and virtual address to physical address.
|
||||
*/
|
||||
if (user)
|
||||
pmap = p->p_vmspace->vm_map.pmap;
|
||||
else
|
||||
pmap = pmap_kernel();
|
||||
|
||||
if (pmap_valid_entry(pmap->pm_pdir[pdei(va)])) {
|
||||
ptes = pmap_map_ptes(pmap); /* locks pmap */
|
||||
pte = ptes[sh3_btop(va)];
|
||||
if (pmap_valid_entry(pte) == FALSE)
|
||||
panic("pmap_emulate_reference: invalid pte");
|
||||
pa = pte & PG_FRAME;
|
||||
pmap_unmap_ptes(pmap); /* unlocks pmap */
|
||||
|
||||
if (!pmap_valid_entry(ptes[sh3_btop(va)]))
|
||||
panic("pmap_set_modify: invalid (unmapped) va");
|
||||
ptes[sh3_btop(va)] |= PG_M;
|
||||
pmap_update_pg(va);
|
||||
pmap_unmap_ptes(pmap); /* unlocks map */
|
||||
}
|
||||
#ifdef DIAGNOSTIC
|
||||
else {
|
||||
panic("pmap_emulate_reference: invalid PDE");
|
||||
}
|
||||
#endif
|
||||
/*
|
||||
* Twiddle the appropriate bits to reflect the reference
|
||||
* and/or modification.
|
||||
*
|
||||
* The rules:
|
||||
* (1) always mark the page as referenced, and
|
||||
* (2) if it was a write fault, mark page as modified.
|
||||
*/
|
||||
|
||||
bank = vm_physseg_find(sh3_btop(pa), &off);
|
||||
if (bank == -1)
|
||||
panic("pmap_emulate_reference: unmanaged page?");
|
||||
pvh = &vm_physmem[bank].pmseg.pvhead[off];
|
||||
|
||||
pte = PG_V; /* referenced */
|
||||
if (write)
|
||||
pte |= PG_M;
|
||||
|
||||
PMAP_HEAD_TO_MAP_LOCK();
|
||||
simple_lock(&pvh->pvh_lock);
|
||||
|
||||
pmap_changebit(pvh, pte, ~0);
|
||||
|
||||
simple_unlock(&pvh->pvh_lock);
|
||||
PMAP_HEAD_TO_MAP_UNLOCK();
|
||||
}
|
||||
|
||||
paddr_t
|
||||
|
|
|
|||
Loading…
Reference in New Issue