Use Access Flag to do page reference emulation.

ok visa@

diff --git a/sys/arch/arm/arm/fault.c b/sys/arch/arm/arm/fault.c
index d90877b..d30455a 100644 (file)
--- a/sys/arch/arm/arm/fault.c
+++ b/sys/arch/arm/arm/fault.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: fault.c,v 1.20 2016/02/27 13:08:06 mpi Exp $  */
+/*     $OpenBSD: fault.c,v 1.21 2016/08/19 13:56:08 kettenis Exp $     */
 /*     $NetBSD: fault.c,v 1.46 2004/01/21 15:39:21 skrll Exp $ */
 
 /*
@@ -154,10 +154,10 @@ static const struct data_abort data_aborts[] = {
        {dab_fatal,     "V7 fault 00000"},
        {dab_align,     "Alignment Fault 1"},
        {dab_fatal,     "Debug Event"},
-       {dab_fatal,     "Access Flag Fault (S)"},
+       {NULL,          "Access Flag Fault (S)"},
        {dab_buserr,    "External Linefetch Abort (S)"},
        {NULL,          "Translation Fault (S)"},
-       {dab_fatal,     "Access Flag Fault (P)"},
+       {NULL,          "Access Flag Fault (P)"},
        {NULL,          "Translation Fault (P)"},
        {dab_buserr,    "External Non-Linefetch Abort (S)"},
        {NULL,          "Domain Fault (S)"},

diff --git a/sys/arch/arm/arm/pmap7.c b/sys/arch/arm/arm/pmap7.c
index 07924e6..5d765a2 100644 (file)
--- a/sys/arch/arm/arm/pmap7.c
+++ b/sys/arch/arm/arm/pmap7.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: pmap7.c,v 1.39 2016/08/18 09:28:22 kettenis Exp $     */
+/*     $OpenBSD: pmap7.c,v 1.40 2016/08/19 13:56:08 kettenis Exp $     */
 /*     $NetBSD: pmap.c,v 1.147 2004/01/18 13:03:50 scw Exp $   */
 
 /*
@@ -921,27 +921,24 @@ pmap_clearbit(struct vm_page *pg, u_int maskbits)
                    pv, pv->pv_pmap, pv->pv_va, oflags));
 
                if (maskbits & (PVF_WRITE|PVF_MOD)) {
-                       /* make the pte read only */
-                       npte = (npte & ~L2_S_PROT_MASK) |
-                           L2_S_PROT(pm == pmap_kernel() ? PTE_KERNEL : PTE_USER,
-                             npte & L2_V7_S_XN ? PROT_READ : PROT_READ | PROT_EXEC);
+                       /* Disable write access. */
+                       npte |= L2_V7_AP(0x4);
                }
 
                if (maskbits & PVF_REF) {
                        /*
-                        * Make the PTE invalid so that we will take a
-                        * page fault the next time the mapping is
-                        * referenced.
+                        * Clear the Access Flag such that we will
+                        * take a page fault the next time the mapping
+                        * is referenced.
                         */
-                       npte = (npte & ~L2_TYPE_MASK) | L2_TYPE_INV |
-                           (npte & L2_V7_S_XN);
+                       npte &= ~L2_V7_AF;
                }
 
                if (npte != opte) {
                        *ptep = npte;
                        PTE_SYNC(ptep);
                        /* Flush the TLB entry if a current pmap. */
-                       if (l2pte_valid(opte))
+                       if (opte & L2_V7_AF)
                                pmap_tlb_flushID_SE(pm, pv->pv_va);
                }
 
@@ -997,7 +994,7 @@ pmap_page_remove(struct vm_page *pg)
        struct l2_bucket *l2b;
        struct pv_entry *pv, *npv;
        pmap_t pm, curpm;
-       pt_entry_t *ptep;
+       pt_entry_t *ptep, opte;
        boolean_t flush;
 
        NPDEBUG(PDB_FOLLOW,
@@ -1020,9 +1017,10 @@ pmap_page_remove(struct vm_page *pg)
                KDASSERT(l2b != NULL);
 
                ptep = &l2b->l2b_kva[l2pte_index(pv->pv_va)];
-               if (*ptep != 0) {
+               opte = *ptep;
+               if (opte != L2_TYPE_INV) {
                        /* inline pmap_is_current(pm) */
-                       if (l2pte_valid(*ptep) &&
+                       if ((opte & L2_V7_AF) &&
                            (pm == curpm || pm == pmap_kernel())) {
                                if (PV_BEEN_EXECD(pv->pv_flags))
                                        cpu_icache_sync_range(pv->pv_va, PAGE_SIZE);
@@ -1136,9 +1134,9 @@ pmap_enter(pmap_t pm, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
        }
        ptep = &l2b->l2b_kva[l2pte_index(va)];
        opte = *ptep;
-       npte = pa | L2_V7_AF;
+       npte = L2_S_PROTO | pa;
 
-       if (opte != 0) {        /* not l2pte_valid!!! MIOD */
+       if (opte != L2_TYPE_INV) {
                /*
                 * There is already a mapping at this address.
                 * If the physical address is different, lookup the
@@ -1164,9 +1162,8 @@ pmap_enter(pmap_t pm, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
                         * - The physical page has already been referenced
                         *   so no need to re-do referenced emulation here.
                         */
-                       npte |= L2_S_PROTO;
-
                        nflags |= PVF_REF;
+                       npte |= L2_V7_AF;
 
                        if ((prot & PROT_WRITE) != 0 &&
                            ((flags & PROT_WRITE) != 0 ||
@@ -1183,8 +1180,6 @@ pmap_enter(pmap_t pm, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
                        /*
                         * Need to do page referenced emulation.
                         */
-                       npte &= ~L2_TYPE_MASK;
-                       npte |= L2_TYPE_INV;
                        prot &= ~PROT_WRITE;
                        mapped = 0;
                }
@@ -1231,7 +1226,7 @@ pmap_enter(pmap_t pm, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
                 * These are always readable, and possibly writable, from
                 * the get go as we don't need to track ref/mod status.
                 */
-               npte |= L2_S_PROTO;
+               npte |= L2_V7_AF;
 
                if (opg) {
                        /*
@@ -1252,7 +1247,7 @@ pmap_enter(pmap_t pm, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
        /*
         * Keep the stats up to date
         */
-       if (opte == 0) {        /* !! not l2pte_valid MIOD */
+       if (opte == L2_TYPE_INV) {
                l2b->l2b_occupancy++;
                pm->pm_stats.resident_count++;
        } 
@@ -1271,7 +1266,7 @@ pmap_enter(pmap_t pm, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
                 * is current
                 */
                PTE_SYNC(ptep);
-               if (/* va != vector_page && */ l2pte_valid(npte)) {
+               if (npte & L2_V7_AF) {
                        /*
                         * This mapping is likely to be accessed as
                         * soon as we return to userland. Fix up the
@@ -1289,7 +1284,7 @@ pmap_enter(pmap_t pm, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
                        }
                }
 
-               if (l2pte_valid(opte))
+               if (opte & L2_V7_AF)
                        pmap_tlb_flushID_SE(pm, va);
        }
 
@@ -1345,7 +1340,7 @@ pmap_remove(pmap_t pm, vaddr_t sva, vaddr_t eva)
 
                        pte = *ptep;
 
-                       if (pte == 0) { /* !!! not l2pte_valid */
+                       if (pte == L2_TYPE_INV) {
                                /*
                                 * Nothing here, move along
                                 */
@@ -1380,7 +1375,7 @@ pmap_remove(pmap_t pm, vaddr_t sva, vaddr_t eva)
 
                        *ptep = L2_TYPE_INV;
                        PTE_SYNC(ptep);
-                       if (l2pte_valid(pte))
+                       if (pte & L2_V7_AF)
                                pmap_tlb_flushID_SE(pm, sva);
 
                        sva += PAGE_SIZE;
@@ -1422,7 +1417,7 @@ pmap_kenter_pa(vaddr_t va, paddr_t pa, vm_prot_t prot)
        ptep = &l2b->l2b_kva[l2pte_index(va)];
        opte = *ptep;
 
-       if (opte == 0)
+       if (opte == L2_TYPE_INV)
                l2b->l2b_occupancy++;
 
        if (pa & PMAP_DEVICE)
@@ -1434,7 +1429,7 @@ pmap_kenter_pa(vaddr_t va, paddr_t pa, vm_prot_t prot)
            L2_S_PROT(PTE_KERNEL, prot) | cache_mode;
        *ptep = npte;
        PTE_SYNC(ptep);
-       if (l2pte_valid(opte)) {
+       if (opte & L2_V7_AF) {
                cpu_tlb_flushD_SE(va);
                cpu_cpwait();
        }
@@ -1479,12 +1474,12 @@ pmap_kremove(vaddr_t va, vsize_t len)
 
                while (va < next_bucket) {
                        opte = *ptep;
-                       if (opte != 0) {        /* !! not l2pte_valid */
+                       if (opte != L2_TYPE_INV) {
                                *ptep = L2_TYPE_INV;
                                PTE_SYNC(ptep);
                                mappings++;
                        }
-                       if (l2pte_valid(opte))
+                       if (opte & L2_V7_AF)
                                cpu_tlb_flushD_SE(va);
                        va += PAGE_SIZE;
                        ptep++;
@@ -1531,7 +1526,7 @@ pmap_extract(pmap_t pm, vaddr_t va, paddr_t *pap)
                ptep = &ptep[l2pte_index(va)];
                pte = *ptep;
 
-               if (pte == 0)   /* !!! not l2pte_valid */
+               if (pte == L2_TYPE_INV)
                        return (FALSE);
 
                switch (pte & L2_TYPE_MASK) {
@@ -1558,7 +1553,7 @@ void
 pmap_protect(pmap_t pm, vaddr_t sva, vaddr_t eva, vm_prot_t prot)
 {
        struct l2_bucket *l2b;
-       pt_entry_t *ptep, pte, opte;
+       pt_entry_t *ptep, opte;
        vaddr_t next_bucket;
        u_int flags;
        int flush;
@@ -1609,17 +1604,12 @@ NPDEBUG(PDB_PROTECT, printf("\n"));
 
                while (sva < next_bucket) {
                        opte = *ptep;
-                       /* !!! not l2pte_valid */
-/* XXX actually would only matter if really valid ??? */
-                       if (opte != 0 && l2pte_is_writeable(opte, pm)) {
+                       if (opte != L2_TYPE_INV && l2pte_is_writeable(opte, pm)) {
                                struct vm_page *pg;
                                u_int f;
 
                                pg = PHYS_TO_VM_PAGE(l2pte_pa(opte));
-                               pte = (opte & ~L2_S_PROT_MASK) |
-                                   L2_S_PROT(pm == pmap_kernel() ? PTE_KERNEL : PTE_USER,
-                                     opte & L2_V7_S_XN ? PROT_READ : PROT_READ | PROT_EXEC);
-                               *ptep = pte;
+                               *ptep = opte | L2_V7_AP(0x4);
                                PTE_SYNC(ptep);
 
                                if (pg != NULL) {
@@ -1630,7 +1620,7 @@ NPDEBUG(PDB_PROTECT, printf("\n"));
 
                                if (flush >= 0) {
                                        flush++;
-                                       if (l2pte_valid(opte))
+                                       if (opte & L2_V7_AF)
                                                cpu_tlb_flushID_SE(sva);
                                } else
                                        flags |= f;
@@ -1759,7 +1749,7 @@ pmap_fault_fixup(pmap_t pm, vaddr_t va, vm_prot_t ftype, int user)
         */
        ptep = &l2b->l2b_kva[l2pte_index(va)];
        pte = *ptep;
-       if (pte == 0)
+       if (pte == L2_TYPE_INV)
                goto out;
 
        /* only if vectors are low ?? */
@@ -1767,9 +1757,7 @@ pmap_fault_fixup(pmap_t pm, vaddr_t va, vm_prot_t ftype, int user)
         * Catch a userland access to the vector page mapped at 0x0
         */
        if (user) {
-               /* XXX use of L2_V7_S_XN */
-               if ((pte & L2_S_PROT_MASK & ~L2_V7_S_XN) != L2_S_PROT(PTE_USER, PROT_READ) &&
-                   (pte & L2_S_PROT_MASK & ~L2_V7_S_XN) != L2_S_PROT(PTE_USER, PROT_WRITE))
+               if ((pte & L2_V7_AP(0x2)) == 0)
                        goto out;
        }
 
@@ -1823,14 +1811,10 @@ Debugger();
                 * We've already set the cacheable bits based on
                 * the assumption that we can write to this page.
                 */
-               *ptep = (pte & ~(L2_TYPE_MASK|L2_S_PROT_MASK)) | L2_S_PROTO |
-                   L2_S_PROT(pm == pmap_kernel() ? PTE_KERNEL : PTE_USER,
-                     pte & L2_V7_S_XN ? PROT_WRITE : PROT_WRITE | PROT_EXEC);
+               *ptep = (pte & ~L2_V7_AP(0x4));
                PTE_SYNC(ptep);
                rv = 1;
-       } else
-       /* XXX use of L2_V7_S_XN */
-       if ((pte & L2_TYPE_MASK & ~L2_V7_S_XN) == L2_TYPE_INV) {
+       } else if ((pte & L2_V7_AF) == 0) {
                /*
                 * This looks like a good candidate for "page referenced"
                 * emulation.
@@ -1849,13 +1833,13 @@ Debugger();
 
                pg->mdpage.pvh_attrs |= PVF_REF;
                pv->pv_flags |= PVF_REF;
+               pte |= L2_V7_AF;
 
                NPDEBUG(PDB_FOLLOW,
                    printf("pmap_fault_fixup: ref emul. pm %p, va 0x%08lx, pa 0x%08lx\n",
                    pm, va, pg->phys_addr));
 
-               /* XXX use of L2_V7_S_XN */
-               *ptep = (pte & ~(L2_TYPE_MASK & ~L2_V7_S_XN)) | L2_S_PROTO;
+               *ptep = pte;
                PTE_SYNC(ptep);
                rv = 1;
        } else {
@@ -2508,7 +2492,7 @@ pmap_bootstrap(pd_entry_t *kernel_l1pt, vaddr_t vstart, vaddr_t vend)
                for (l2idx = 0;
                    l2idx < (L2_TABLE_SIZE_REAL / sizeof(pt_entry_t));
                    l2idx++) {
-                       if ((ptep[l2idx] & L2_TYPE_MASK) != L2_TYPE_INV)
+                       if (ptep[l2idx] != L2_TYPE_INV)
                                l2b->l2b_occupancy++;
                }
        }

diff --git a/sys/arch/arm/include/pmap.h b/sys/arch/arm/include/pmap.h
index c3a1729..718e1bc 100644 (file)
--- a/sys/arch/arm/include/pmap.h
+++ b/sys/arch/arm/include/pmap.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: pmap.h,v 1.42 2016/08/10 21:22:43 kettenis Exp $      */
+/*     $OpenBSD: pmap.h,v 1.43 2016/08/19 13:56:08 kettenis Exp $      */
 /*     $NetBSD: pmap.h,v 1.76 2003/09/06 09:10:46 rearnsha Exp $       */
 
 /*
@@ -758,10 +758,7 @@ L2_S_PROT(int ku, vm_prot_t pr)
 static __inline boolean_t
 l2pte_is_writeable(pt_entry_t pte, struct pmap *pm)
 {
-       /* XXX use of L2_V7_S_XN */
-       return (pte & L2_S_PROT_MASK & ~L2_V7_S_XN) ==
-           L2_S_PROT(pm == pmap_kernel() ? PTE_KERNEL : PTE_USER,
-                     PROT_WRITE);
+       return (pte & L2_V7_AP(0x4)) == 0;
 }
 #endif