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Change pmap_demote_l2_locked() so that it removes the superpage mapping on a

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demotion failure.  Otherwise, some callers to pmap_demote_l2_locked(), such
as pmap_protect(), may leave an incorrect mapping in place on a demotion
failure.

Change pmap_demote_l2_locked() so that it handles addresses that are not
superpage aligned.  Some callers to pmap_demote_l2_locked(), such as
pmap_protect(), may not pass a superpage aligned address.

Change pmap_enter_l2() so that it correctly calls vm_page_free_pages_toq().
The arm64 pmap is updating the count of wired pages when freeing page table
pages, so pmap_enter_l2() should pass false to vm_page_free_pages_toq().

Optimize TLB invalidation in pmap_remove_l2().

Reviewed by:	kib, markj (an earlier version)
Discussed with:	andrew
MFC after:	3 weeks
Differential Revision:	https://reviews.freebsd.org/D20585
This commit is contained in:
Alan Cox 2019-06-12 20:38:49 +00:00
parent 4b3f792718
commit a04cd5cdee
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=349003
1 changed files with 75 additions and 13 deletions
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88
sys/arm64/arm64/pmap.c
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@ -2267,6 +2267,8 @@ pmap_pv_demote_l2(pmap_t pmap, vm_offset_t va, vm_paddr_t pa,
int bit, field;
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
KASSERT((va & L2_OFFSET) == 0,
("pmap_pv_demote_l2: va is not 2mpage aligned"));
KASSERT((pa & L2_OFFSET) == 0,
("pmap_pv_demote_l2: pa is not 2mpage aligned"));
CHANGE_PV_LIST_LOCK_TO_PHYS(lockp, pa);
@ -2277,7 +2279,6 @@ pmap_pv_demote_l2(pmap_t pmap, vm_offset_t va, vm_paddr_t pa,
* must not be released until the last pv entry is reinstantiated.
*/
pvh = pa_to_pvh(pa);
va = va & ~L2_OFFSET;
pv = pmap_pvh_remove(pvh, pmap, va);
KASSERT(pv != NULL, ("pmap_pv_demote_l2: pv not found"));
m = PHYS_TO_VM_PAGE(pa);
@ -2433,7 +2434,13 @@ pmap_remove_l2(pmap_t pmap, pt_entry_t *l2, vm_offset_t sva,
old_l2 = pmap_load_clear(l2);
KASSERT((old_l2 & ATTR_DESCR_MASK) == L2_BLOCK,
("pmap_remove_l2: L2e %lx is not a block mapping", old_l2));
pmap_invalidate_range(pmap, sva, sva + L2_SIZE);
/*
* Since a promotion must break the 4KB page mappings before making
* the 2MB page mapping, a pmap_invalidate_page() suffices.
*/
pmap_invalidate_page(pmap, sva);
if (old_l2 & ATTR_SW_WIRED)
pmap->pm_stats.wired_count -= L2_SIZE / PAGE_SIZE;
pmap_resident_count_dec(pmap, L2_SIZE / PAGE_SIZE);
@ -2571,8 +2578,8 @@ pmap_remove(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
pmap_remove_l2(pmap, l2, sva, pmap_load(l1),
&free, &lock);
continue;
} else if (pmap_demote_l2_locked(pmap, l2,
sva &~L2_OFFSET, &lock) == NULL)
} else if (pmap_demote_l2_locked(pmap, l2, sva,
&lock) == NULL)
continue;
l3_paddr = pmap_load(l2);
}
@ -3052,8 +3059,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
if (pde != NULL && lvl == 1) {
l2 = pmap_l1_to_l2(pde, va);
if ((pmap_load(l2) & ATTR_DESCR_MASK) == L2_BLOCK &&
(l3 = pmap_demote_l2_locked(pmap, l2, va & ~L2_OFFSET,
&lock)) != NULL) {
(l3 = pmap_demote_l2_locked(pmap, l2, va, &lock)) != NULL) {
l3 = &l3[pmap_l3_index(va)];
if (va < VM_MAXUSER_ADDRESS) {
mpte = PHYS_TO_VM_PAGE(
@ -3391,7 +3397,7 @@ pmap_enter_l2(pmap_t pmap, vm_offset_t va, pd_entry_t new_l2, u_int flags,
lockp) != 0)
break;
}
vm_page_free_pages_toq(&free, true);
vm_page_free_pages_toq(&free, false);
if (va >= VM_MAXUSER_ADDRESS) {
/*
* Both pmap_remove_l2() and pmap_remove_l3() will
@ -3419,7 +3425,7 @@ pmap_enter_l2(pmap_t pmap, vm_offset_t va, pd_entry_t new_l2, u_int flags,
* Invalidate those entries.
*/
pmap_invalidate_page(pmap, va);
vm_page_free_pages_toq(&free, true);
vm_page_free_pages_toq(&free, false);
}
CTR2(KTR_PMAP,
"pmap_enter_l2: failure for va %#lx in pmap %p",
@ -4331,8 +4337,7 @@ pmap_remove_write(vm_page_t m)
va = pv->pv_va;
pte = pmap_pte(pmap, pv->pv_va, &lvl);
if ((pmap_load(pte) & ATTR_AP_RW_BIT) == ATTR_AP(ATTR_AP_RW))
pmap_demote_l2_locked(pmap, pte, va & ~L2_OFFSET,
&lock);
(void)pmap_demote_l2_locked(pmap, pte, va, &lock);
KASSERT(lock == VM_PAGE_TO_PV_LIST_LOCK(m),
("inconsistent pv lock %p %p for page %p",
lock, VM_PAGE_TO_PV_LIST_LOCK(m), m));
@ -4906,7 +4911,7 @@ pmap_change_attr_locked(vm_offset_t va, vm_size_t size, int mode)
pte = pmap_l1_to_l2(pte, tmpva);
case 2:
newpte = pmap_demote_l2(kernel_pmap, pte,
tmpva & ~L2_OFFSET);
tmpva);
if (newpte == NULL)
return (EINVAL);
pte = pmap_l2_to_l3(pte, tmpva);
@ -5005,6 +5010,18 @@ pmap_demote_l1(pmap_t pmap, pt_entry_t *l1, vm_offset_t va)
return (l2);
}
static void
pmap_demote_l2_abort(pmap_t pmap, vm_offset_t va, pt_entry_t *l2,
struct rwlock **lockp)
{
struct spglist free;
SLIST_INIT(&free);
(void)pmap_remove_l2(pmap, l2, va, pmap_load(pmap_l1(pmap, va)), &free,
lockp);
vm_page_free_pages_toq(&free, false);
}
/*
* Create an L3 table to map all addresses within an L2 mapping.
*/
@ -5023,8 +5040,7 @@ pmap_demote_l2_locked(pmap_t pmap, pt_entry_t *l2, vm_offset_t va,
oldl2 = pmap_load(l2);
KASSERT((oldl2 & ATTR_DESCR_MASK) == L2_BLOCK,
("pmap_demote_l2: Demoting a non-block entry"));
KASSERT((va & L2_OFFSET) == 0,
("pmap_demote_l2: Invalid virtual address %#lx", va));
va &= ~L2_OFFSET;
tmpl2 = 0;
if (va <= (vm_offset_t)l2 && va + L2_SIZE > (vm_offset_t)l2) {
@ -5033,15 +5049,57 @@ pmap_demote_l2_locked(pmap_t pmap, pt_entry_t *l2, vm_offset_t va,
return (NULL);
}
/*
* Invalidate the 2MB page mapping and return "failure" if the
* mapping was never accessed.
*/
if ((oldl2 & ATTR_AF) == 0) {
KASSERT((oldl2 & ATTR_SW_WIRED) == 0,
("pmap_demote_l2: a wired mapping is missing ATTR_AF"));
pmap_demote_l2_abort(pmap, va, l2, lockp);
CTR2(KTR_PMAP, "pmap_demote_l2: failure for va %#lx in pmap %p",
va, pmap);
goto fail;
}
if ((ml3 = pmap_remove_pt_page(pmap, va)) == NULL) {
KASSERT((oldl2 & ATTR_SW_WIRED) == 0,
("pmap_demote_l2: page table page for a wired mapping"
" is missing"));
/*
* If the page table page is missing and the mapping
* is for a kernel address, the mapping must belong to
* the direct map. Page table pages are preallocated
* for every other part of the kernel address space,
* so the direct map region is the only part of the
* kernel address space that must be handled here.
*/
KASSERT(va < VM_MAXUSER_ADDRESS || VIRT_IN_DMAP(va),
("pmap_demote_l2: No saved mpte for va %#lx", va));
/*
* If the 2MB page mapping belongs to the direct map
* region of the kernel's address space, then the page
* allocation request specifies the highest possible
* priority (VM_ALLOC_INTERRUPT). Otherwise, the
* priority is normal.
*/
ml3 = vm_page_alloc(NULL, pmap_l2_pindex(va),
(VIRT_IN_DMAP(va) ? VM_ALLOC_INTERRUPT : VM_ALLOC_NORMAL) |
VM_ALLOC_NOOBJ | VM_ALLOC_WIRED);
/*
* If the allocation of the new page table page fails,
* invalidate the 2MB page mapping and return "failure".
*/
if (ml3 == NULL) {
pmap_demote_l2_abort(pmap, va, l2, lockp);
CTR2(KTR_PMAP, "pmap_demote_l2: failure for va %#lx"
" in pmap %p", va, pmap);
goto fail;
}
if (va < VM_MAXUSER_ADDRESS) {
ml3->wire_count = NL3PG;
pmap_resident_count_inc(pmap, 1);
@ -5090,6 +5148,10 @@ pmap_demote_l2_locked(pmap_t pmap, pt_entry_t *l2, vm_offset_t va,
if ((oldl2 & ATTR_SW_MANAGED) != 0)
reserve_pv_entries(pmap, Ln_ENTRIES - 1, lockp);
/*
* Pass PAGE_SIZE so that a single TLB invalidation is performed on
* the 2MB page mapping.
*/
pmap_update_entry(pmap, l2, l3phys | L2_TABLE, va, PAGE_SIZE);
/*