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Add support for pmap_enter(..., psind=1) to the armv6 pmap. In other words,

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add support for explicitly requesting that pmap_enter() create a 1 MB page
mapping.  (Essentially, this feature allows the machine-independent layer
to create superpage mappings preemptively, and not wait for automatic
promotion to occur.)

Export pmap_ps_enabled() to the machine-independent layer.

Add a flag to pmap_pv_insert_pte1() that specifies whether it should fail
or reclaim a PV entry when one is not available.

Refactor pmap_enter_pte1() into two functions, one by the same name, that
is a general-purpose function for creating pte1 mappings, and another,
pmap_enter_1mpage(), that is used to prefault 1 MB read- and/or execute-
only mappings for execve(2), mmap(2), and shmat(2).

In addition, as an optimization to pmap_enter(..., psind=0), eliminate the
use of pte2_is_managed() from pmap_enter().  Unlike the x86 pmap
implementations, armv6 does not have a managed bit defined within the PTE.
So, pte2_is_managed() is actually a call to PHYS_TO_VM_PAGE(), which is O(n)
in the number of vm_phys_segs[].  All but one call to PHYS_TO_VM_PAGE() in
pmap_enter() can be avoided.

Reviewed by:	kib, markj, mmel
Tested by:	mmel
MFC after:	6 weeks
Differential Revision:	https://reviews.freebsd.org/D16555
This commit is contained in:
Alan Cox 2018-08-08 16:55:01 +00:00
parent 6371d0bd64
commit 2bf8cb3804
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=337463
3 changed files with 153 additions and 67 deletions
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208
sys/arm/arm/pmap-v6.c
View File

@ -323,9 +323,17 @@ SYSCTL_INT(_debug, OID_AUTO, PMAP1unchanged, CTLFLAG_RD,
"Number of times pmap_pte2_quick didn't change PMAP1");
static struct mtx PMAP2mutex;
/*
* Internal flags for pmap_enter()'s helper functions.
*/
#define PMAP_ENTER_NORECLAIM 0x1000000 /* Don't reclaim PV entries. */
#define PMAP_ENTER_NOREPLACE 0x2000000 /* Don't replace mappings. */
static __inline void pt2_wirecount_init(vm_page_t m);
static boolean_t pmap_demote_pte1(pmap_t pmap, pt1_entry_t *pte1p,
vm_offset_t va);
static int pmap_enter_pte1(pmap_t pmap, vm_offset_t va, pt1_entry_t pte1,
u_int flags, vm_page_t m);
void cache_icache_sync_fresh(vm_offset_t va, vm_paddr_t pa, vm_size_t size);
/*
@ -1557,6 +1565,13 @@ static int sp_enabled = 1;
SYSCTL_INT(_vm_pmap, OID_AUTO, sp_enabled, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
&sp_enabled, 0, "Are large page mappings enabled?");
bool
pmap_ps_enabled(pmap_t pmap __unused)
{
return (sp_enabled != 0);
}
static SYSCTL_NODE(_vm_pmap, OID_AUTO, pte1, CTLFLAG_RD, 0,
"1MB page mapping counters");
@ -3227,21 +3242,22 @@ pmap_try_insert_pv_entry(pmap_t pmap, vm_offset_t va, vm_page_t m)
/*
* Create the pv entries for each of the pages within a section.
*/
static boolean_t
pmap_pv_insert_pte1(pmap_t pmap, vm_offset_t va, vm_paddr_t pa)
static bool
pmap_pv_insert_pte1(pmap_t pmap, vm_offset_t va, pt1_entry_t pte1, u_int flags)
{
struct md_page *pvh;
pv_entry_t pv;
bool noreclaim;
rw_assert(&pvh_global_lock, RA_WLOCKED);
if (pv_entry_count < pv_entry_high_water &&
(pv = get_pv_entry(pmap, TRUE)) != NULL) {
pv->pv_va = va;
pvh = pa_to_pvh(pa);
TAILQ_INSERT_TAIL(&pvh->pv_list, pv, pv_next);
return (TRUE);
} else
return (FALSE);
noreclaim = (flags & PMAP_ENTER_NORECLAIM) != 0;
if ((noreclaim && pv_entry_count >= pv_entry_high_water) ||
(pv = get_pv_entry(pmap, noreclaim)) == NULL)
return (false);
pv->pv_va = va;
pvh = pa_to_pvh(pte1_pa(pte1));
TAILQ_INSERT_TAIL(&pvh->pv_list, pv, pv_next);
return (true);
}
static inline void
@ -3879,7 +3895,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
if ((prot & VM_PROT_WRITE) == 0)
npte2 |= PTE2_RO;
KASSERT((npte2 & (PTE2_NM | PTE2_RO)) != PTE2_RO,
("pmap_enter: flags includes VM_PROT_WRITE but prot doesn't"));
("%s: flags includes VM_PROT_WRITE but prot doesn't", __func__));
if ((prot & VM_PROT_EXECUTE) == 0)
npte2 |= PTE2_NX;
if ((flags & PMAP_ENTER_WIRED) != 0)
@ -3892,6 +3908,15 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
rw_wlock(&pvh_global_lock);
PMAP_LOCK(pmap);
sched_pin();
if (psind == 1) {
/* Assert the required virtual and physical alignment. */
KASSERT((va & PTE1_OFFSET) == 0,
("%s: va unaligned", __func__));
KASSERT(m->psind > 0, ("%s: m->psind < psind", __func__));
rv = pmap_enter_pte1(pmap, va, PTE1_PA(pa) | ATTR_TO_L1(npte2) |
PTE1_V, flags, m);
goto out;
}
/*
* In the case that a page table page is not
@ -3937,7 +3962,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
*/
if (mpte2)
pt2_wirecount_dec(mpte2, pte1_index(va));
if (pte2_is_managed(opte2))
if ((m->oflags & VPO_UNMANAGED) == 0)
om = m;
goto validate;
}
@ -3962,10 +3987,12 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
if (opa) {
if (pte2_is_wired(opte2))
pmap->pm_stats.wired_count--;
if (pte2_is_managed(opte2)) {
om = PHYS_TO_VM_PAGE(opa);
om = PHYS_TO_VM_PAGE(opa);
if (om != NULL && (om->oflags & VPO_UNMANAGED) != 0)
om = NULL;
if (om != NULL)
pv = pmap_pvh_remove(&om->md, pmap, va);
}
/*
* Remove extra pte2 reference
*/
@ -3997,7 +4024,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
* Now validate mapping with desired protection/wiring.
*/
if (prot & VM_PROT_WRITE) {
if (pte2_is_managed(npte2))
if ((m->oflags & VPO_UNMANAGED) == 0)
vm_page_aflag_set(m, PGA_WRITEABLE);
}
@ -4034,19 +4061,18 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
opte2 = pte2_load_clear(pte2p);
pmap_tlb_flush(pmap, va);
pte2_store(pte2p, npte2);
if (opte2 & PTE2_A) {
if (pte2_is_managed(opte2))
if (om != NULL) {
KASSERT((om->oflags & VPO_UNMANAGED) == 0,
("%s: om %p unmanaged", __func__, om));
if ((opte2 & PTE2_A) != 0)
vm_page_aflag_set(om, PGA_REFERENCED);
}
if (pte2_is_dirty(opte2)) {
if (pte2_is_managed(opte2))
if (pte2_is_dirty(opte2))
vm_page_dirty(om);
if (TAILQ_EMPTY(&om->md.pv_list) &&
((om->flags & PG_FICTITIOUS) != 0 ||
TAILQ_EMPTY(&pa_to_pvh(opa)->pv_list)))
vm_page_aflag_clear(om, PGA_WRITEABLE);
}
if (pte2_is_managed(opte2) &&
TAILQ_EMPTY(&om->md.pv_list) &&
((om->flags & PG_FICTITIOUS) != 0 ||
TAILQ_EMPTY(&pa_to_pvh(opa)->pv_list)))
vm_page_aflag_clear(om, PGA_WRITEABLE);
} else
pte2_store(pte2p, npte2);
}
@ -4652,66 +4678,124 @@ pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
}
/*
* Tries to create 1MB page mapping. Returns TRUE if successful and
* FALSE otherwise. Fails if (1) a page table page cannot be allocated without
* blocking, (2) a mapping already exists at the specified virtual address, or
* (3) a pv entry cannot be allocated without reclaiming another pv entry.
* Tries to create a read- and/or execute-only 1 MB page mapping. Returns
* true if successful. Returns false if (1) a mapping already exists at the
* specified virtual address or (2) a PV entry cannot be allocated without
* reclaiming another PV entry.
*/
static boolean_t
pmap_enter_pte1(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
static bool
pmap_enter_1mpage(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
{
pt1_entry_t *pte1p;
pt1_entry_t pte1;
vm_paddr_t pa;
uint32_t l1prot;
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
pa = VM_PAGE_TO_PHYS(m);
pte1 = PTE1(pa, PTE1_NM | PTE1_RO, ATTR_TO_L1(vm_page_pte2_attr(m)));
if ((prot & VM_PROT_EXECUTE) == 0)
pte1 |= PTE1_NX;
if (va < VM_MAXUSER_ADDRESS)
pte1 |= PTE1_U;
if (pmap != kernel_pmap)
pte1 |= PTE1_NG;
return (pmap_enter_pte1(pmap, va, pte1, PMAP_ENTER_NOSLEEP |
PMAP_ENTER_NOREPLACE | PMAP_ENTER_NORECLAIM, m) == KERN_SUCCESS);
}
/*
* Tries to create the specified 1 MB page mapping. Returns KERN_SUCCESS if
* the mapping was created, and either KERN_FAILURE or KERN_RESOURCE_SHORTAGE
* otherwise. Returns KERN_FAILURE if PMAP_ENTER_NOREPLACE was specified and
* a mapping already exists at the specified virtual address. Returns
* KERN_RESOURCE_SHORTAGE if PMAP_ENTER_NORECLAIM was specified and PV entry
* allocation failed.
*/
static int
pmap_enter_pte1(pmap_t pmap, vm_offset_t va, pt1_entry_t pte1, u_int flags,
vm_page_t m)
{
struct spglist free;
pt1_entry_t opte1, *pte1p;
pt2_entry_t pte2, *pte2p;
vm_offset_t cur, end;
vm_page_t mt;
rw_assert(&pvh_global_lock, RA_WLOCKED);
KASSERT((pte1 & (PTE1_NM | PTE1_RO)) == 0 ||
(pte1 & (PTE1_NM | PTE1_RO)) == (PTE1_NM | PTE1_RO),
("%s: pte1 has inconsistent NM and RO attributes", __func__));
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
pte1p = pmap_pte1(pmap, va);
if (pte1_is_valid(pte1_load(pte1p))) {
CTR3(KTR_PMAP, "%s: failure for va %#lx in pmap %p", __func__,
va, pmap);
return (FALSE);
opte1 = pte1_load(pte1p);
if (pte1_is_valid(opte1)) {
if ((flags & PMAP_ENTER_NOREPLACE) != 0) {
CTR3(KTR_PMAP, "%s: failure for va %#lx in pmap %p",
__func__, va, pmap);
return (KERN_FAILURE);
}
/* Break the existing mapping(s). */
SLIST_INIT(&free);
if (pte1_is_section(opte1)) {
/*
* If the section resulted from a promotion, then a
* reserved PT page could be freed.
*/
pmap_remove_pte1(pmap, pte1p, va, &free);
} else {
sched_pin();
end = va + PTE1_SIZE;
for (cur = va, pte2p = pmap_pte2_quick(pmap, va);
cur != end; cur += PAGE_SIZE, pte2p++) {
pte2 = pte2_load(pte2p);
if (!pte2_is_valid(pte2))
continue;
if (pmap_remove_pte2(pmap, pte2p, cur, &free))
break;
}
sched_unpin();
}
vm_page_free_pages_toq(&free, false);
}
if ((m->oflags & VPO_UNMANAGED) == 0) {
/*
* Abort this mapping if its PV entry could not be created.
*/
if (!pmap_pv_insert_pte1(pmap, va, VM_PAGE_TO_PHYS(m))) {
if (!pmap_pv_insert_pte1(pmap, va, pte1, flags)) {
CTR3(KTR_PMAP, "%s: failure for va %#lx in pmap %p",
__func__, va, pmap);
return (FALSE);
return (KERN_RESOURCE_SHORTAGE);
}
if ((pte1 & PTE1_RO) == 0) {
for (mt = m; mt < &m[PTE1_SIZE / PAGE_SIZE]; mt++)
vm_page_aflag_set(mt, PGA_WRITEABLE);
}
}
/*
* Increment counters.
*/
if (pte1_is_wired(pte1))
pmap->pm_stats.wired_count += PTE1_SIZE / PAGE_SIZE;
pmap->pm_stats.resident_count += PTE1_SIZE / PAGE_SIZE;
/*
* Map the section.
*
* QQQ: Why VM_PROT_WRITE is not evaluated and the mapping is
* made readonly?
* Sync icache if exec permission and attribute VM_MEMATTR_WB_WA
* is set. QQQ: For more info, see comments in pmap_enter().
*/
pa = VM_PAGE_TO_PHYS(m);
l1prot = PTE1_RO | PTE1_NM;
if (va < VM_MAXUSER_ADDRESS)
l1prot |= PTE1_U | PTE1_NG;
if ((prot & VM_PROT_EXECUTE) == 0)
l1prot |= PTE1_NX;
else if (m->md.pat_mode == VM_MEMATTR_WB_WA && pmap != kernel_pmap) {
/*
* Sync icache if exec permission and attribute VM_MEMATTR_WB_WA
* is set. QQQ: For more info, see comments in pmap_enter().
*/
cache_icache_sync_fresh(va, pa, PTE1_SIZE);
}
pte1_store(pte1p, PTE1(pa, l1prot, ATTR_TO_L1(vm_page_pte2_attr(m))));
if ((pte1 & PTE1_NX) == 0 && m->md.pat_mode == VM_MEMATTR_WB_WA &&
pmap != kernel_pmap && (!pte1_is_section(opte1) ||
pte1_pa(opte1) != VM_PAGE_TO_PHYS(m) || (opte1 & PTE2_NX) != 0))
cache_icache_sync_fresh(va, VM_PAGE_TO_PHYS(m), PTE1_SIZE);
/*
* Map the section.
*/
pte1_store(pte1p, pte1);
pmap_pte1_mappings++;
CTR3(KTR_PMAP, "%s: success for va %#lx in pmap %p", __func__, va,
pmap);
return (TRUE);
return (KERN_SUCCESS);
}
/*
@ -4747,7 +4831,7 @@ pmap_enter_object(pmap_t pmap, vm_offset_t start, vm_offset_t end,
va = start + ptoa(diff);
if ((va & PTE1_OFFSET) == 0 && va + PTE1_SIZE <= end &&
m->psind == 1 && sp_enabled &&
pmap_enter_pte1(pmap, va, m, prot))
pmap_enter_1mpage(pmap, va, m, prot))
m = &m[PTE1_SIZE / PAGE_SIZE - 1];
else
mpt2pg = pmap_enter_quick_locked(pmap, va, m, prot,
@ -6020,8 +6104,8 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr, vm_size_t len,
continue;
if (dst_pmap->pm_pt1[pte1_idx] == 0 &&
(!pte1_is_managed(src_pte1) ||
pmap_pv_insert_pte1(dst_pmap, addr,
pte1_pa(src_pte1)))) {
pmap_pv_insert_pte1(dst_pmap, addr, src_pte1,
PMAP_ENTER_NORECLAIM))) {
dst_pmap->pm_pt1[pte1_idx] = src_pte1 &
~PTE1_W;
dst_pmap->pm_stats.resident_count +=

1
sys/arm/include/pmap-v6.h
View File

@ -167,6 +167,7 @@ void pmap_bootstrap(vm_offset_t);
void pmap_kenter(vm_offset_t, vm_paddr_t);
void pmap_kremove(vm_offset_t);
boolean_t pmap_page_is_mapped(vm_page_t);
bool pmap_ps_enabled(pmap_t pmap);
void pmap_tlb_flush(pmap_t, vm_offset_t);
void pmap_tlb_flush_range(pmap_t, vm_offset_t, vm_size_t);

11
sys/vm/vm_fault.c
View File

@ -270,8 +270,8 @@ vm_fault_soft_fast(struct faultstate *fs, vm_offset_t vaddr, vm_prot_t prot,
int fault_type, int fault_flags, boolean_t wired, vm_page_t *m_hold)
{
vm_page_t m, m_map;
#if (defined(__amd64__) || defined(__i386__) || defined(__aarch64__)) && \
VM_NRESERVLEVEL > 0
#if (defined(__aarch64__) || defined(__amd64__) || (defined(__arm__) && \
__ARM_ARCH >= 6) || defined(__i386__)) && VM_NRESERVLEVEL > 0
vm_page_t m_super;
int flags;
#endif
@ -285,8 +285,8 @@ vm_fault_soft_fast(struct faultstate *fs, vm_offset_t vaddr, vm_prot_t prot,
return (KERN_FAILURE);
m_map = m;
psind = 0;
#if (defined(__amd64__) || defined(__i386__) || defined(__aarch64__)) && \
VM_NRESERVLEVEL > 0
#if (defined(__aarch64__) || defined(__amd64__) || (defined(__arm__) && \
__ARM_ARCH >= 6) || defined(__i386__)) && VM_NRESERVLEVEL > 0
if ((m->flags & PG_FICTITIOUS) == 0 &&
(m_super = vm_reserv_to_superpage(m)) != NULL &&
rounddown2(vaddr, pagesizes[m_super->psind]) >= fs->entry->start &&
@ -462,7 +462,8 @@ vm_fault_populate(struct faultstate *fs, vm_prot_t prot, int fault_type,
pidx <= pager_last;
pidx += npages, m = vm_page_next(&m[npages - 1])) {
vaddr = fs->entry->start + IDX_TO_OFF(pidx) - fs->entry->offset;
#if defined(__amd64__) || defined(__i386__) || defined(__aarch64__)
#if defined(__aarch64__) || defined(__amd64__) || (defined(__arm__) && \
__ARM_ARCH >= 6) || defined(__i386__)
psind = m->psind;
if (psind > 0 && ((vaddr & (pagesizes[psind] - 1)) != 0 ||
pidx + OFF_TO_IDX(pagesizes[psind]) - 1 > pager_last ||