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Add support for pmap_enter(..., psind=1) to the i386 pmap. In other words,

Browse Source 
add support for explicitly requesting that pmap_enter() create a 2 or 4 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_pde() that specifies whether it should fail or
reclaim a PV entry when one is not available.

Refactor pmap_enter_pde() into two functions, one by the same name, that is
a general-purpose function for creating PDE PG_PS mappings, and another,
pmap_enter_4mpage(), that is used to prefault 2 or 4 MB read- and/or
execute-only mappings for execve(2), mmap(2), and shmat(2).

Reviewed by:	kib
Tested by:	pho
Differential Revision:	https://reviews.freebsd.org/D16246
This commit is contained in:
Alan Cox 2018-07-14 17:20:27 +00:00
parent 179d82aecf
commit 8c0873714c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=336288
3 changed files with 170 additions and 61 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

224
sys/i386/i386/pmap.c
View File

@ -285,11 +285,18 @@ static struct mtx PMAP2mutex;
int pti;
/*
* 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 void free_pv_chunk(struct pv_chunk *pc);
static void free_pv_entry(pmap_t pmap, pv_entry_t pv);
static pv_entry_t get_pv_entry(pmap_t pmap, boolean_t try);
static void pmap_pv_demote_pde(pmap_t pmap, vm_offset_t va, vm_paddr_t pa);
static boolean_t pmap_pv_insert_pde(pmap_t pmap, vm_offset_t va, vm_paddr_t pa);
static bool pmap_pv_insert_pde(pmap_t pmap, vm_offset_t va, pd_entry_t pde,
u_int flags);
#if VM_NRESERVLEVEL > 0
static void pmap_pv_promote_pde(pmap_t pmap, vm_offset_t va, vm_paddr_t pa);
#endif
@ -299,8 +306,10 @@ static pv_entry_t pmap_pvh_remove(struct md_page *pvh, pmap_t pmap,
static int pmap_pvh_wired_mappings(struct md_page *pvh, int count);
static boolean_t pmap_demote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va);
static boolean_t pmap_enter_pde(pmap_t pmap, vm_offset_t va, vm_page_t m,
vm_prot_t prot);
static bool pmap_enter_4mpage(pmap_t pmap, vm_offset_t va, vm_page_t m,
vm_prot_t prot);
static int pmap_enter_pde(pmap_t pmap, vm_offset_t va, pd_entry_t newpde,
u_int flags, vm_page_t m);
static vm_page_t pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va,
vm_page_t m, vm_prot_t prot, vm_page_t mpte);
static void pmap_flush_page(vm_page_t m);
@ -326,6 +335,8 @@ static int pmap_remove_pte(pmap_t pmap, pt_entry_t *ptq, vm_offset_t sva,
static vm_page_t pmap_remove_pt_page(pmap_t pmap, vm_offset_t va);
static void pmap_remove_page(struct pmap *pmap, vm_offset_t va,
struct spglist *free);
static bool pmap_remove_ptes(pmap_t pmap, vm_offset_t sva, vm_offset_t eva,
struct spglist *free);
static void pmap_remove_entry(struct pmap *pmap, vm_page_t m,
vm_offset_t va);
static void pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t m);
@ -1068,6 +1079,13 @@ pmap_cache_bits(int mode, boolean_t is_pde)
return (cache_bits);
}
bool
pmap_ps_enabled(pmap_t pmap)
{
return (pg_ps_enabled);
}
/*
* The caller is responsible for maintaining TLB consistency.
*/
@ -2702,21 +2720,22 @@ 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 superpage.
*/
static boolean_t
pmap_pv_insert_pde(pmap_t pmap, vm_offset_t va, vm_paddr_t pa)
static bool
pmap_pv_insert_pde(pmap_t pmap, vm_offset_t va, pd_entry_t pde, 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(pde & PG_PS_FRAME);
TAILQ_INSERT_TAIL(&pvh->pv_list, pv, pv_next);
return (true);
}
/*
@ -3025,6 +3044,38 @@ pmap_remove_page(pmap_t pmap, vm_offset_t va, struct spglist *free)
pmap_invalidate_page(pmap, va);
}
/*
* Removes the specified range of addresses from the page table page.
*/
static bool
pmap_remove_ptes(pmap_t pmap, vm_offset_t sva, vm_offset_t eva,
struct spglist *free)
{
pt_entry_t *pte;
bool anyvalid;
rw_assert(&pvh_global_lock, RA_WLOCKED);
KASSERT(curthread->td_pinned > 0, ("curthread not pinned"));
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
anyvalid = false;
for (pte = pmap_pte_quick(pmap, sva); sva != eva; pte++,
sva += PAGE_SIZE) {
if (*pte == 0)
continue;
/*
* The TLB entry for a PG_G mapping is invalidated by
* pmap_remove_pte().
*/
if ((*pte & PG_G) == 0)
anyvalid = true;
if (pmap_remove_pte(pmap, pte, sva, free))
break;
}
return (anyvalid);
}
/*
* Remove the given range of addresses from the specified map.
*
@ -3036,7 +3087,6 @@ pmap_remove(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
{
vm_offset_t pdnxt;
pd_entry_t ptpaddr;
pt_entry_t *pte;
struct spglist free;
int anyvalid;
@ -3119,20 +3169,8 @@ pmap_remove(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
if (pdnxt > eva)
pdnxt = eva;
for (pte = pmap_pte_quick(pmap, sva); sva != pdnxt; pte++,
sva += PAGE_SIZE) {
if (*pte == 0)
continue;
/*
* The TLB entry for a PG_G mapping is invalidated
* by pmap_remove_pte().
*/
if ((*pte & PG_G) == 0)
anyvalid = 1;
if (pmap_remove_pte(pmap, pte, sva, &free))
break;
}
if (pmap_remove_ptes(pmap, sva, pdnxt, &free))
anyvalid = 1;
}
out:
sched_unpin();
@ -3614,6 +3652,13 @@ 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 & PDRMASK) == 0, ("pmap_enter: va unaligned"));
KASSERT(m->psind > 0, ("pmap_enter: m->psind < psind"));
rv = pmap_enter_pde(pmap, va, newpte | PG_PS, flags, m);
goto out;
}
pde = pmap_pde(pmap, va);
if (pmap != kernel_pmap) {
@ -3812,48 +3857,111 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
}
/*
* Tries to create a 2- or 4MB 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 2 or 4 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_pde(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
static bool
pmap_enter_4mpage(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
{
pd_entry_t *pde, newpde;
pd_entry_t newpde;
rw_assert(&pvh_global_lock, RA_WLOCKED);
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
pde = pmap_pde(pmap, va);
if (*pde != 0) {
CTR2(KTR_PMAP, "pmap_enter_pde: failure for va %#lx"
" in pmap %p", va, pmap);
return (FALSE);
}
newpde = VM_PAGE_TO_PHYS(m) | pmap_cache_bits(m->md.pat_mode, 1) |
PG_PS | PG_V;
if ((m->oflags & VPO_UNMANAGED) == 0) {
if ((m->oflags & VPO_UNMANAGED) == 0)
newpde |= PG_MANAGED;
/*
* Abort this mapping if its PV entry could not be created.
*/
if (!pmap_pv_insert_pde(pmap, va, VM_PAGE_TO_PHYS(m))) {
CTR2(KTR_PMAP, "pmap_enter_pde: failure for va %#lx"
" in pmap %p", va, pmap);
return (FALSE);
}
}
#if defined(PAE) || defined(PAE_TABLES)
if ((prot & VM_PROT_EXECUTE) == 0)
newpde |= pg_nx;
#endif
if (va < VM_MAXUSER_ADDRESS)
if (pmap != kernel_pmap)
newpde |= PG_U;
return (pmap_enter_pde(pmap, va, newpde, PMAP_ENTER_NOSLEEP |
PMAP_ENTER_NOREPLACE | PMAP_ENTER_NORECLAIM, NULL) ==
KERN_SUCCESS);
}
/*
* Tries to create the specified 2 or 4 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 a PV entry allocation failed.
*
* The parameter "m" is only used when creating a managed, writeable mapping.
*/
static int
pmap_enter_pde(pmap_t pmap, vm_offset_t va, pd_entry_t newpde, u_int flags,
vm_page_t m)
{
struct spglist free;
pd_entry_t oldpde, *pde;
vm_page_t mt;
rw_assert(&pvh_global_lock, RA_WLOCKED);
KASSERT((newpde & (PG_M | PG_RW)) != PG_RW,
("pmap_enter_pde: newpde is missing PG_M"));
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
pde = pmap_pde(pmap, va);
oldpde = *pde;
if ((oldpde & PG_V) != 0) {
if ((flags & PMAP_ENTER_NOREPLACE) != 0) {
CTR2(KTR_PMAP, "pmap_enter_pde: failure for va %#lx"
" in pmap %p", va, pmap);
return (KERN_FAILURE);
}
/* Break the existing mapping(s). */
SLIST_INIT(&free);
if ((oldpde & PG_PS) != 0) {
/*
* If the PDE resulted from a promotion, then a
* reserved PT page could be freed.
*/
(void)pmap_remove_pde(pmap, pde, va, &free);
if ((oldpde & PG_G) == 0)
pmap_invalidate_pde_page(pmap, va, oldpde);
} else {
if (pmap_remove_ptes(pmap, va, va + NBPDR, &free))
pmap_invalidate_all(pmap);
}
vm_page_free_pages_toq(&free, true);
if (pmap == kernel_pmap) {
mt = PHYS_TO_VM_PAGE(*pde & PG_FRAME);
if (pmap_insert_pt_page(pmap, mt)) {
/*
* XXX Currently, this can't happen because
* we do not perform pmap_enter(psind == 1)
* on the kernel pmap.
*/
panic("pmap_enter_pde: trie insert failed");
}
} else
KASSERT(*pde == 0, ("pmap_enter_pde: non-zero pde %p",
pde));
}
if ((newpde & PG_MANAGED) != 0) {
/*
* Abort this mapping if its PV entry could not be created.
*/
if (!pmap_pv_insert_pde(pmap, va, newpde, flags)) {
CTR2(KTR_PMAP, "pmap_enter_pde: failure for va %#lx"
" in pmap %p", va, pmap);
return (KERN_RESOURCE_SHORTAGE);
}
if ((newpde & PG_RW) != 0) {
for (mt = m; mt < &m[NBPDR / PAGE_SIZE]; mt++)
vm_page_aflag_set(mt, PGA_WRITEABLE);
}
}
/*
* Increment counters.
*/
if ((newpde & PG_W) != 0)
pmap->pm_stats.wired_count += NBPDR / PAGE_SIZE;
pmap->pm_stats.resident_count += NBPDR / PAGE_SIZE;
/*
@ -3865,7 +3973,7 @@ pmap_enter_pde(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
pmap_pde_mappings++;
CTR2(KTR_PMAP, "pmap_enter_pde: success for va %#lx"
" in pmap %p", va, pmap);
return (TRUE);
return (KERN_SUCCESS);
}
/*
@ -3899,7 +4007,7 @@ pmap_enter_object(pmap_t pmap, vm_offset_t start, vm_offset_t end,
va = start + ptoa(diff);
if ((va & PDRMASK) == 0 && va + NBPDR <= end &&
m->psind == 1 && pg_ps_enabled &&
pmap_enter_pde(pmap, va, m, prot))
pmap_enter_4mpage(pmap, va, m, prot))
m = &m[NBPDR / PAGE_SIZE - 1];
else
mpte = pmap_enter_quick_locked(pmap, va, m, prot,
@ -4273,8 +4381,8 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr, vm_size_t len,
continue;
if (dst_pmap->pm_pdir[ptepindex] == 0 &&
((srcptepaddr & PG_MANAGED) == 0 ||
pmap_pv_insert_pde(dst_pmap, addr, srcptepaddr &
PG_PS_FRAME))) {
pmap_pv_insert_pde(dst_pmap, addr, srcptepaddr,
PMAP_ENTER_NORECLAIM))) {
dst_pmap->pm_pdir[ptepindex] = srcptepaddr &
~PG_W;
dst_pmap->pm_stats.resident_count +=

1
sys/i386/include/pmap.h
View File

@ -387,6 +387,7 @@ void *pmap_mapdev(vm_paddr_t, vm_size_t);
void *pmap_mapdev_attr(vm_paddr_t, vm_size_t, int);
boolean_t pmap_page_is_mapped(vm_page_t m);
void pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma);
bool pmap_ps_enabled(pmap_t pmap);
void pmap_unmapdev(vm_offset_t, vm_size_t);
pt_entry_t *pmap_pte(pmap_t, vm_offset_t) __pure2;
void pmap_invalidate_page(pmap_t, vm_offset_t);

6
sys/vm/vm_fault.c
View File

@ -270,7 +270,7 @@ 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__) && VM_NRESERVLEVEL > 0
#if (defined(__amd64__) || defined(__i386__)) && VM_NRESERVLEVEL > 0
vm_page_t m_super;
int flags;
#endif
@ -284,7 +284,7 @@ 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__) && VM_NRESERVLEVEL > 0
#if (defined(__amd64__) || 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 &&
@ -460,7 +460,7 @@ 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__)
#if defined(__amd64__) || defined(__i386__)
psind = m->psind;
if (psind > 0 && ((vaddr & (pagesizes[psind] - 1)) != 0 ||
pidx + OFF_TO_IDX(pagesizes[psind]) - 1 > pager_last ||