[src/trunk]: src/sys/arch/sparc/sparc Simplify pmap_page_protect(); modelled ...

[pk <pk%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6de132bf32e9
branches:  trunk
changeset: 485650:6de132bf32e9
user:      pk <pk%NetBSD.org@localhost>
date:      Tue May 02 13:06:27 2000 +0000

description:
Simplify pmap_page_protect(); modelled after a similar change by
Art Grabowski in Openbsd.

diffstat:

 sys/arch/sparc/sparc/pmap.c |  84 ++++++++++++++++++++------------------------
 1 files changed, 39 insertions(+), 45 deletions(-)

diffs (188 lines):

diff -r 93ed92739ea2 -r 6de132bf32e9 sys/arch/sparc/sparc/pmap.c
--- a/sys/arch/sparc/sparc/pmap.c       Tue May 02 12:50:50 2000 +0000
+++ b/sys/arch/sparc/sparc/pmap.c       Tue May 02 13:06:27 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.161 2000/05/02 10:35:06 pk Exp $ */
+/*     $NetBSD: pmap.c,v 1.162 2000/05/02 13:06:27 pk Exp $ */
 
 /*
  * Copyright (c) 1996
@@ -4099,8 +4099,6 @@
                return;
 
 #ifdef DIAGNOSTIC
-       if (va < virtual_avail)
-               panic("pmap_rmk4m: attempt to free base kernel addr %lx", va);
        if (sp->sg_pte == NULL || rp->rg_seg_ptps == NULL)
                panic("pmap_rmk: segment/region does not exist");
        if (pm->pm_ctx == NULL)
@@ -4497,9 +4495,11 @@
        if ((pa & (PMAP_TNC_4 & ~PMAP_NC)) ||
             !managed(pa) || prot & VM_PROT_WRITE)
                return;
+
        write_user_windows();   /* paranoia */
+       pv = pvhead(pa);
        if (prot & VM_PROT_READ) {
-               pv_changepte4_4c(pvhead(pa), 0, PG_W);
+               pv_changepte4_4c(pv, 0, PG_W);
                return;
        }
 
@@ -4509,16 +4509,19 @@
         * The logic is much like that for pmap_remove,
         * but we know we are removing exactly one page.
         */
-       pv = pvhead(pa);
        s = splpmap();
-       if ((pm = pv->pv_pmap) == NULL) {
+       if (pv->pv_pmap == NULL) {
                splx(s);
                return;
        }
        ctx = getcontext4();
        pv0 = pv;
-       flags = pv->pv_flags & ~PV_NC;
-       for (;; pm = pv->pv_pmap) {
+
+       /* This pv head will become empty, so clear caching state flags */
+       flags = pv->pv_flags & ~(PV_NC|PV_ANC);
+
+       while (pv != NULL) {
+               pm = pv->pv_pmap;
                va = pv->pv_va;
                vr = VA_VREG(va);
                vs = VA_VSEG(va);
@@ -4528,8 +4531,8 @@
                sp = &rp->rg_segmap[vs];
                if ((nleft = sp->sg_npte) == 0)
                        panic("pmap_remove_all: empty vseg");
-               nleft--;
-               sp->sg_npte = nleft;
+
+               sp->sg_npte = --nleft;
 
                if (sp->sg_pmeg == seginval) {
                        /* Definitely not a kernel map */
@@ -4639,11 +4642,12 @@
                npv = pv->pv_next;
                if (pv != pv0)
                        pool_put(&pv_pool, pv);
-               if ((pv = npv) == NULL)
-                       break;
-       }
+               pv = npv;
+       }
+
+       /* Finally, update pv head */
        pv0->pv_pmap = NULL;
-       pv0->pv_next = NULL; /* ? */
+       pv0->pv_next = NULL;
        pv0->pv_flags = flags;
        setcontext4(ctx);
        splx(s);
@@ -4893,9 +4897,11 @@
         */
        if (!managed(pa) || prot & VM_PROT_WRITE)
                return;
+
        write_user_windows();   /* paranoia */
+       pv = pvhead(pa);
        if (prot & VM_PROT_READ) {
-               pv_changepte4m(pvhead(pa), 0, PPROT_WRITE);
+               pv_changepte4m(pv, 0, PPROT_WRITE);
                return;
        }
 
@@ -4905,16 +4911,19 @@
         * The logic is much like that for pmap_remove,
         * but we know we are removing exactly one page.
         */
-       pv = pvhead(pa);
        s = splpmap();
-       if ((pm = pv->pv_pmap) == NULL) {
+       if (pv->pv_pmap == NULL) {
                splx(s);
                return;
        }
        ctx = getcontext4m();
        pv0 = pv;
-       flags = pv->pv_flags /*| PV_C4M*/;      /* %%%: ???? */
-       for (;; pm = pv->pv_pmap) {
+
+       /* This pv head will become empty, so clear caching state flags */
+       flags = pv->pv_flags & ~(PV_C4M|PV_ANC);
+
+       while (pv != NULL) {
+               pm = pv->pv_pmap;
                va = pv->pv_va;
                vr = VA_VREG(va);
                vs = VA_VSEG(va);
@@ -4924,8 +4933,7 @@
                sp = &rp->rg_segmap[vs];
                if ((nleft = sp->sg_npte) == 0)
                        panic("pmap_remove_all: empty vseg");
-               nleft--;
-               sp->sg_npte = nleft;
+               sp->sg_npte = --nleft;
 
                /* Invalidate PTE in MMU pagetables. Flush cache if necessary */
                if (pm->pm_ctx) {
@@ -4935,31 +4943,17 @@
                }
 
                tpte = sp->sg_pte[VA_SUN4M_VPG(va)];
+               setpgt4m(&sp->sg_pte[VA_SUN4M_VPG(va)], SRMMU_TEINVALID);
 
                if ((tpte & SRMMU_TETYPE) != SRMMU_TEPTE)
                        panic("pmap_page_protect !PG_V");
 
                flags |= MR4M(tpte);
 
-               if (nleft) {
-                       setpgt4m(&sp->sg_pte[VA_SUN4M_VPG(va)], SRMMU_TEINVALID);
-                       goto nextpv;
-               }
-
-               /* Entire segment is gone */
-               if (pm == pmap_kernel()) {
-                       tlb_flush_segment(vr, vs); /* Paranoid? */
-                       setpgt4m(&sp->sg_pte[VA_SUN4M_VPG(va)], SRMMU_TEINVALID);
-                       if (va < virtual_avail) {
-#ifdef DEBUG
-                               printf(
-                                "pmap_page_protect: attempt to free"
-                                " base kernel allocation\n");
-#endif
-                               goto nextpv;
-                       }
-
-               } else {        /* User mode mapping */
+               if (nleft == 0 && pm != pmap_kernel()) {
+                       /*
+                        * Entire user mode segment is gone
+                        */
                        if (pm->pm_ctx)
                                tlb_flush_segment(vr, vs);
                        setpgt4m(&rp->rg_seg_ptps[vs], SRMMU_TEINVALID);
@@ -4990,15 +4984,15 @@
                        }
                }
 
-       nextpv:
                npv = pv->pv_next;
                if (pv != pv0)
                        pool_put(&pv_pool, pv);
-               if ((pv = npv) == NULL)
-                       break;
-       }
+               pv = npv;
+       }
+
+       /* Finally, update pv head */
        pv0->pv_pmap = NULL;
-       pv0->pv_next = NULL; /* ? */
+       pv0->pv_next = NULL;
        pv0->pv_flags = flags;
        setcontext4m(ctx);
        splx(s);