from netbsd:

Prevent possible race condition in ctx_alloc().
Remove some bogus casts
Make pmap_prefer() also return a preferred virtual address when there's no
associated physical page

diff --git a/sys/arch/sparc/sparc/pmap.c b/sys/arch/sparc/sparc/pmap.c
index 38c717e..be83605 100644 (file)
--- a/sys/arch/sparc/sparc/pmap.c
+++ b/sys/arch/sparc/sparc/pmap.c
@@ -1079,7 +1079,7 @@ ctx_alloc(pm)
        register struct pmap *pm;
 {
        register union ctxinfo *c;
-       register int cnum, i;
+       register int s, cnum, i, doflush;
        register struct regmap *rp;
        register int gap_start, gap_end;
        register unsigned long va;
@@ -1093,10 +1093,11 @@ ctx_alloc(pm)
        gap_start = pm->pm_gap_start;
        gap_end = pm->pm_gap_end;
 
+       s = splpmap();
        if ((c = ctx_freelist) != NULL) {
                ctx_freelist = c->c_nextfree;
                cnum = c - ctxinfo;
-               setcontext(cnum);
+               doflush = 0;
        } else {
                if ((ctx_kick += ctx_kickdir) >= ncontext) {
                        ctx_kick = ncontext - 1;
@@ -1114,17 +1115,20 @@ ctx_alloc(pm)
                            cnum, c->c_pmap);
 #endif
                c->c_pmap->pm_ctx = NULL;
-               setcontext(cnum);
-               if (vactype != VAC_NONE)
-                       cache_flush_context();
+               doflush = (vactype != VAC_NONE);
                if (gap_start < c->c_pmap->pm_gap_start)
                        gap_start = c->c_pmap->pm_gap_start;
                if (gap_end > c->c_pmap->pm_gap_end)
                        gap_end = c->c_pmap->pm_gap_end;
        }
+
+       setcontext(cnum);
        c->c_pmap = pm;
        pm->pm_ctx = c;
        pm->pm_ctxnum = cnum;
+       splx(s);
+       if (doflush)
+               cache_flush_context();
 
        /*
         * Write pmap's region (3-level MMU) or segment table into the MMU.
@@ -1408,7 +1412,7 @@ pv_unlink(pv, pm, va)
                        pv->pv_next = npv->pv_next;
                        pv->pv_pmap = npv->pv_pmap;
                        pv->pv_va = npv->pv_va;
-                       free((caddr_t)npv, M_VMPVENT);
+                       free(npv, M_VMPVENT);
                } else
                        pv->pv_pmap = NULL;
        } else {
@@ -1422,7 +1426,7 @@ pv_unlink(pv, pm, va)
                                break;
                }
                prev->pv_next = npv->pv_next;
-               free((caddr_t)npv, M_VMPVENT);
+               free(npv, M_VMPVENT);
        }
        if (pv->pv_flags & PV_NC) {
                /*
@@ -2066,7 +2070,7 @@ pmap_destroy(pm)
        simple_unlock(&pm->pm_lock);
        if (count == 0) {
                pmap_release(pm);
-               free((caddr_t)pm, M_VMPMAP);
+               free(pm, M_VMPMAP);
        }
 }
 
@@ -2124,7 +2128,7 @@ pmap_release(pm)
 }
 #endif
        if (pm->pm_regstore)
-               free((caddr_t)pm->pm_regstore, M_VMPMAP);
+               free(pm->pm_regstore, M_VMPMAP);
 }
 
 /*
@@ -2382,10 +2386,10 @@ pmap_rmu(pm, va, endva, vr, vs)
                        *pte = 0;
                }
                if ((sp->sg_npte = nleft) == 0) {
-                       free((caddr_t)pte0, M_VMPMAP);
+                       free(pte0, M_VMPMAP);
                        sp->sg_pte = NULL;
                        if (--rp->rg_nsegmap == 0) {
-                               free((caddr_t)rp->rg_segmap, M_VMPMAP);
+                               free(rp->rg_segmap, M_VMPMAP);
                                rp->rg_segmap = NULL;
 #ifdef MMU_3L
                                if (mmu_3l && rp->rg_smeg != reginval) {
@@ -2472,12 +2476,12 @@ if (pm->pm_ctx == NULL) {
                        setsegmap(vs << SGSHIFT, seginval);
                }
 #endif
-               free((caddr_t)pte0, M_VMPMAP);
+               free(pte0, M_VMPMAP);
                sp->sg_pte = NULL;
                me_free(pm, pmeg);
 
                if (--rp->rg_nsegmap == 0) {
-                       free((caddr_t)rp->rg_segmap, M_VMPMAP);
+                       free(rp->rg_segmap, M_VMPMAP);
                        rp->rg_segmap = NULL;
                        GAP_WIDEN(pm,vr);
 
@@ -2567,10 +2571,10 @@ pmap_page_protect(pa, prot)
                        if (nleft) {
                                sp->sg_pte[VA_VPG(va)] = 0;
                        } else {
-                               free((caddr_t)sp->sg_pte, M_VMPMAP);
+                               free(sp->sg_pte, M_VMPMAP);
                                sp->sg_pte = NULL;
                                if (--rp->rg_nsegmap == 0) {
-                                       free((caddr_t)rp->rg_segmap, M_VMPMAP);
+                                       free(rp->rg_segmap, M_VMPMAP);
                                        rp->rg_segmap = NULL;
                                        GAP_WIDEN(pm,vr);
 #ifdef MMU_3L
@@ -2646,7 +2650,7 @@ pmap_page_protect(pa, prot)
                                        setsegmap(vs << SGSHIFT, seginval);
                                }
 #endif
-                               free((caddr_t)sp->sg_pte, M_VMPMAP);
+                               free(sp->sg_pte, M_VMPMAP);
                                sp->sg_pte = NULL;
                                me_free(pm, sp->sg_pmeg);
 
@@ -2658,7 +2662,7 @@ pmap_page_protect(pa, prot)
                                                region_free(pm, rp->rg_smeg);
                                        }
 #endif
-                                       free((caddr_t)rp->rg_segmap, M_VMPMAP);
+                                       free(rp->rg_segmap, M_VMPMAP);
                                        rp->rg_segmap = NULL;
                                        GAP_WIDEN(pm,vr);
                                }
@@ -2667,7 +2671,7 @@ pmap_page_protect(pa, prot)
        nextpv:
                npv = pv->pv_next;
                if (pv != pv0)
-                       free((caddr_t)pv, M_VMPVENT);
+                       free(pv, M_VMPVENT);
                if ((pv = npv) == NULL)
                        break;
        }
@@ -3133,7 +3137,7 @@ rretry:
                sp = (struct segmap *)malloc((u_long)size, M_VMPMAP, M_WAITOK);
                if (rp->rg_segmap != NULL) {
 printf("pmap_enter: segment filled during sleep\n");   /* can this happen? */
-                       free((caddr_t)sp, M_VMPMAP);
+                       free(sp, M_VMPMAP);
                        goto rretry;
                }
                bzero((caddr_t)sp, size);
@@ -3153,7 +3157,7 @@ sretry:
                pte = (int *)malloc((u_long)size, M_VMPMAP, M_WAITOK);
                if (sp->sg_pte != NULL) {
 printf("pmap_enter: pte filled during sleep\n");       /* can this happen? */
-                       free((caddr_t)pte, M_VMPMAP);
+                       free(pte, M_VMPMAP);
                        goto sretry;
                }
 #ifdef DEBUG
@@ -3626,23 +3630,31 @@ pmap_prefer(pa, va)
        register struct pvlist  *pv;
        register long           m, d;
 
-       if (cputyp == CPU_SUN4M)
-               /* does the sun4m have the cache alias problem? */
-               return va;
-
        m = CACHE_ALIAS_DIST;
+       if (m == 0)             /* m=0 => no cache aliasing */
+               return (va);
+
+       if (pa == (vm_offset_t)-1) {
+               /*
+                * Do not consider physical address. Just return
+                * a cache aligned address.
+                */     
+               if (VA_INHOLE(va))
+                       va = MMU_HOLE_END;
+
+               /* XXX - knowledge about `exec' formats; can we get by without? */
+               va -= USRTEXT;
+               va = (va + m - 1) & ~(m - 1);
+               return (va + USRTEXT);
+       }
 
        if ((pa & (PMAP_TNC & ~PMAP_NC)) || !managed(pa))
                return va;
 
        pv = pvhead(pa);
        if (pv->pv_pmap == NULL) {
-#if 0
-               return ((va + m - 1) & ~(m - 1));
-#else
                /* Unusable, tell caller to try another one */
                return (vm_offset_t)-1;
-#endif
        }
 
        d = (long)(pv->pv_va & (m - 1)) - (long)(va & (m - 1));