svn commit: r336288 - in head/sys: i386/i386 i386/include vm
Alan Cox
alc at FreeBSD.org
Sat Jul 14 17:20:28 UTC 2018
Author: alc
Date: Sat Jul 14 17:20:27 2018
New Revision: 336288
URL: https://svnweb.freebsd.org/changeset/base/336288
Log:
Add support for pmap_enter(..., psind=1) to the i386 pmap. In other words,
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
Modified:
head/sys/i386/i386/pmap.c
head/sys/i386/include/pmap.h
head/sys/vm/vm_fault.c
Modified: head/sys/i386/i386/pmap.c
==============================================================================
--- head/sys/i386/i386/pmap.c Sat Jul 14 17:18:17 2018 (r336287)
+++ head/sys/i386/i386/pmap.c Sat Jul 14 17:20:27 2018 (r336288)
@@ -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,
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 *pt
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,
/*
* 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);
}
/*
@@ -3026,6 +3045,38 @@ pmap_remove_page(pmap_t pmap, vm_offset_t va, struct s
}
/*
+ * 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.
*
* It is assumed that the start and end are properly
@@ -3036,7 +3087,6 @@ pmap_remove(pmap_t pmap, vm_offset_t sva, vm_offset_t
{
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
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, v
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 @@ out:
}
/*
- * 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;
+#if defined(PAE) || defined(PAE_TABLES)
+ if ((prot & VM_PROT_EXECUTE) == 0)
+ newpde |= pg_nx;
+#endif
+ 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, VM_PAGE_TO_PHYS(m))) {
+ 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 (FALSE);
+ 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);
+ }
}
-#if defined(PAE) || defined(PAE_TABLES)
- if ((prot & VM_PROT_EXECUTE) == 0)
- newpde |= pg_nx;
-#endif
- if (va < VM_MAXUSER_ADDRESS)
- newpde |= PG_U;
/*
* 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
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_o
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_
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 +=
Modified: head/sys/i386/include/pmap.h
==============================================================================
--- head/sys/i386/include/pmap.h Sat Jul 14 17:18:17 2018 (r336287)
+++ head/sys/i386/include/pmap.h Sat Jul 14 17:20:27 2018 (r336288)
@@ -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);
Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c Sat Jul 14 17:18:17 2018 (r336287)
+++ head/sys/vm/vm_fault.c Sat Jul 14 17:20:27 2018 (r336288)
@@ -270,7 +270,7 @@ vm_fault_soft_fast(struct faultstate *fs, vm_offset_t
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
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 pro
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 ||
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