/* * Copyright (c) 1993, 1994 Charles Hannum. * Copyright (c) 1991 Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department and William Jolitz of UUNET Technologies Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: @(#)pmap.c 7.7 (Berkeley) 5/12/91 * $Id: pmap.c,v 1.19.2.2 1994/10/18 10:06:18 cgd Exp $ */ /* * Derived originally from an old hp300 version by Mike Hibler. The version * by William Jolitz has been heavily modified to allow non-contiguous * mapping of physical memory by Wolfgang Solfrank, and to fix several bugs * and greatly speedup it up by Charles Hannum. * * A recursive map [a pde which points to the page directory] is used to map * the page tables using the pagetables themselves. This is done to reduce * the impact on kernel virtual memory for lots of sparse address space, and * to reduce the cost of memory to each process. */ /* * Manages physical address maps. * * In addition to hardware address maps, this * module is called upon to provide software-use-only * maps which may or may not be stored in the same * form as hardware maps. These pseudo-maps are * used to store intermediate results from copy * operations to and from address spaces. * * Since the information managed by this module is * also stored by the logical address mapping module, * this module may throw away valid virtual-to-physical * mappings at almost any time. However, invalidations * of virtual-to-physical mappings must be done as * requested. * * In order to cope with hardware architectures which * make virtual-to-physical map invalidates expensive, * this module may delay invalidate or reduced protection * operations until such time as they are actually * necessary. This module is given full information as * to which processors are currently using which maps, * and to when physical maps must be made correct. */ #include #include #include #include #include #include #include #include #include #include "isa.h" /* * Allocate various and sundry SYSMAPs used in the days of old VM * and not yet converted. XXX. */ #define BSDVM_COMPAT 1 #ifdef DEBUG struct { int kernel; /* entering kernel mapping */ int user; /* entering user mapping */ int ptpneeded; /* needed to allocate a PT page */ int pwchange; /* no mapping change, just wiring or protection */ int wchange; /* no mapping change, just wiring */ int mchange; /* was mapped but mapping to different page */ int managed; /* a managed page */ int firstpv; /* first mapping for this PA */ int secondpv; /* second mapping for this PA */ int ci; /* cache inhibited */ int unmanaged; /* not a managed page */ int flushes; /* cache flushes */ } enter_stats; struct { int calls; int removes; int pvfirst; int pvsearch; int ptinvalid; int uflushes; int sflushes; } remove_stats; int pmapdebug = 0 /* 0xffff */; #define PDB_FOLLOW 0x0001 #define PDB_INIT 0x0002 #define PDB_ENTER 0x0004 #define PDB_REMOVE 0x0008 #define PDB_CREATE 0x0010 #define PDB_PTPAGE 0x0020 #define PDB_CACHE 0x0040 #define PDB_BITS 0x0080 #define PDB_COLLECT 0x0100 #define PDB_PROTECT 0x0200 #define PDB_PDRTAB 0x0400 #define PDB_PARANOIA 0x2000 #define PDB_WIRING 0x4000 #define PDB_PVDUMP 0x8000 #endif /* * Get PDEs and PTEs for user/kernel address space */ #define pmap_pde(m, v) (&((m)->pm_pdir[((vm_offset_t)(v) >> PDSHIFT)&1023])) /* * Empty PTEs and PDEs are always 0, but checking only the valid bit allows * the compiler to generate `testb' rather than `testl'. */ #define pmap_pde_v(pde) (*(pde) & PG_V) #define pmap_pte_pa(pte) (*(pte) & PG_FRAME) #define pmap_pte_w(pte) (*(pte) & PG_W) #define pmap_pte_m(pte) (*(pte) & PG_M) #define pmap_pte_u(pte) (*(pte) & PG_U) #define pmap_pte_v(pte) (*(pte) & PG_V) #define pmap_pte_set_w(pte, v) ((v) ? (*(pte) |= PG_W) : (*(pte) &= ~PG_W)) #define pmap_pte_set_prot(pte, v) ((*(pte) &= ~PG_PROT), (*(pte) |= (v))) /* * Given a map and a machine independent protection code, * convert to a vax protection code. */ pt_entry_t protection_codes[8]; struct pmap kernel_pmap_store; vm_offset_t avail_start; /* PA of first available physical page */ vm_offset_t avail_end; /* PA of last available physical page */ vm_offset_t virtual_avail; /* VA of first avail page (after kernel bss)*/ vm_offset_t virtual_end; /* VA of last avail page (end of kernel AS) */ int npages; boolean_t pmap_initialized = FALSE; /* Has pmap_init completed? */ char *pmap_attributes; /* reference and modify bits */ TAILQ_HEAD(pv_page_list, pv_page) pv_page_freelist; int pv_nfree; pt_entry_t *pmap_pte __P((pmap_t, vm_offset_t)); #if BSDVM_COMPAT #include /* * All those kernel PT submaps that BSD is so fond of */ pt_entry_t *CMAP1, *CMAP2, *XXX_mmap; caddr_t CADDR1, CADDR2, vmmap; pt_entry_t *msgbufmap; #endif /* BSDVM_COMPAT */ /* * Bootstrap the system enough to run with virtual memory. * Map the kernel's code and data, and allocate the system page table. * * On the I386 this is called after mapping has already been enabled * and just syncs the pmap module with what has already been done. * [We can't call it easily with mapping off since the kernel is not * mapped with PA == VA, hence we would have to relocate every address * from the linked base (virtual) address to the actual (physical) * address starting relative to 0] */ void pmap_bootstrap(virtual_start) vm_offset_t virtual_start; { #if BSDVM_COMPAT vm_offset_t va; pt_entry_t *pte; #endif extern int physmem; #if notyet extern vm_offset_t reserve_dumppages(vm_offset_t); #endif extern int IdlePTD; /* XXX: allow for msgbuf */ avail_end -= i386_round_page(sizeof(struct msgbuf)); virtual_avail = virtual_start; virtual_end = VM_MAX_KERNEL_ADDRESS; /* * Initialize protection array. */ i386_protection_init(); #ifdef notdef /* * Create Kernel page directory table and page maps. * [ currently done in locore. i have wild and crazy ideas -wfj ] */ bzero(firstaddr, (1+NKPDE)*NBPG); kernel_pmap->pm_pdir = firstaddr + VM_MIN_KERNEL_ADDRESS; kernel_pmap->pm_ptab = firstaddr + VM_MIN_KERNEL_ADDRESS + NBPG; firstaddr += NBPG; for (x = i386_btod(VM_MIN_KERNEL_ADDRESS); x < i386_btod(VM_MIN_KERNEL_ADDRESS) + NKPDE; x++) { pd_entry_t *pde; pde = kernel_pmap->pm_pdir + x; *pde = (firstaddr + x*NBPG) | PG_V | PG_KW; } #else kernel_pmap->pm_pdir = (pd_entry_t *)(KERNBASE + IdlePTD); #endif simple_lock_init(&kernel_pmap->pm_lock); kernel_pmap->pm_count = 1; #if BSDVM_COMPAT /* * Allocate all the submaps we need */ #define SYSMAP(c, p, v, n) \ v = (c)va; va += ((n)*NBPG); p = pte; pte += (n); va = virtual_avail; pte = pmap_pte(kernel_pmap, va); SYSMAP(caddr_t ,CMAP1 ,CADDR1 ,1 ) SYSMAP(caddr_t ,CMAP2 ,CADDR2 ,1 ) SYSMAP(caddr_t ,XXX_mmap ,vmmap ,1 ) SYSMAP(struct msgbuf * ,msgbufmap ,msgbufp ,1 ) virtual_avail = va; #endif #if notyet /* * Reserve pmap space for mapping physical pages during dump. */ virtual_avail = reserve_dumppages(virtual_avail); #endif /* * reserve special hunk of memory for use by bus dma as a bounce * buffer (contiguous virtual *and* physical memory). XXX */ #if NISA > 0 isaphysmem = pmap_steal_memory(DMA_BOUNCE * NBPG); #endif /* XXX undo temporary double mapping */ *PTD = 0; pmap_update(); } void pmap_virtual_space(startp, endp) vm_offset_t *startp; vm_offset_t *endp; { *startp = virtual_avail; *endp = virtual_end; } /* * Initialize the pmap module. * Called by vm_init, to initialize any structures that the pmap * system needs to map virtual memory. */ void pmap_init() { vm_offset_t addr, addr2; vm_size_t s; int rv; extern int KPTphys; if (PAGE_SIZE != NBPG) panic("pmap_init: CLSIZE != 1"); npages = pmap_page_index(avail_end - 1) + 1; s = (vm_size_t) (sizeof(struct pv_entry) * npages + npages); s = round_page(s); addr = (vm_offset_t) kmem_alloc(kernel_map, s); pv_table = (struct pv_entry *) addr; addr += sizeof(struct pv_entry) * npages; pmap_attributes = (char *) addr; TAILQ_INIT(&pv_page_freelist); #ifdef DEBUG if (pmapdebug & PDB_INIT) printf("pmap_init: %x bytes (%x pgs): tbl %x attr %x\n", s, npages, pv_table, pmap_attributes); #endif /* * Now it is safe to enable pv_table recording. */ pmap_initialized = TRUE; } struct pv_entry * pmap_alloc_pv() { struct pv_page *pvp; struct pv_entry *pv; int i; if (pv_nfree == 0) { MALLOC(pvp, struct pv_page *, NBPG, M_VMPVENT, M_NOWAIT); if (pvp == 0) panic("pmap_alloc_pv: kmem_alloc() failed"); pvp->pvp_pgi.pgi_freelist = pv = &pvp->pvp_pv[1]; for (i = NPVPPG - 2; i; i--, pv++) pv->pv_next = pv + 1; pv->pv_next = 0; pv_nfree += pvp->pvp_pgi.pgi_nfree = NPVPPG - 1; TAILQ_INSERT_HEAD(&pv_page_freelist, pvp, pvp_pgi.pgi_list); pv = &pvp->pvp_pv[0]; } else { --pv_nfree; pvp = pv_page_freelist.tqh_first; if (--pvp->pvp_pgi.pgi_nfree == 0) { TAILQ_REMOVE(&pv_page_freelist, pvp, pvp_pgi.pgi_list); } pv = pvp->pvp_pgi.pgi_freelist; #ifdef DIAGNOSTIC if (pv == 0) panic("pmap_alloc_pv: pgi_nfree inconsistent"); #endif pvp->pvp_pgi.pgi_freelist = pv->pv_next; } return pv; } void pmap_free_pv(pv) struct pv_entry *pv; { register struct pv_page *pvp; register int i; pvp = (struct pv_page *) trunc_page(pv); switch (++pvp->pvp_pgi.pgi_nfree) { case 1: TAILQ_INSERT_TAIL(&pv_page_freelist, pvp, pvp_pgi.pgi_list); default: pv->pv_next = pvp->pvp_pgi.pgi_freelist; pvp->pvp_pgi.pgi_freelist = pv; ++pv_nfree; break; case NPVPPG: pv_nfree -= NPVPPG - 1; TAILQ_REMOVE(&pv_page_freelist, pvp, pvp_pgi.pgi_list); FREE(pvp, M_VMPVENT); break; } } void pmap_collect_pv() { struct pv_page_list pv_page_collectlist; struct pv_page *pvp, *npvp; struct pv_entry *ph, *ppv, *pv, *npv; int s; TAILQ_INIT(&pv_page_collectlist); for (pvp = pv_page_freelist.tqh_first; pvp; pvp = npvp) { if (pv_nfree < NPVPPG) break; npvp = pvp->pvp_pgi.pgi_list.tqe_next; if (pvp->pvp_pgi.pgi_nfree > NPVPPG / 3) { TAILQ_REMOVE(&pv_page_freelist, pvp, pvp_pgi.pgi_list); TAILQ_INSERT_TAIL(&pv_page_collectlist, pvp, pvp_pgi.pgi_list); pv_nfree -= pvp->pvp_pgi.pgi_nfree; pvp->pvp_pgi.pgi_nfree = -1; } } if (pv_page_collectlist.tqh_first == 0) return; for (ph = &pv_table[npages - 1]; ph >= &pv_table[0]; ph--) { if (ph->pv_pmap == 0) continue; s = splimp(); for (ppv = ph; (pv = ppv->pv_next) != 0; ) { pvp = (struct pv_page *) trunc_page(pv); if (pvp->pvp_pgi.pgi_nfree == -1) { pvp = pv_page_freelist.tqh_first; if (--pvp->pvp_pgi.pgi_nfree == 0) { TAILQ_REMOVE(&pv_page_freelist, pvp, pvp_pgi.pgi_list); } npv = pvp->pvp_pgi.pgi_freelist; #ifdef DIAGNOSTIC if (npv == 0) panic("pmap_collect_pv: pgi_nfree inconsistent"); #endif pvp->pvp_pgi.pgi_freelist = npv->pv_next; *npv = *pv; ppv->pv_next = npv; ppv = npv; } else ppv = pv; } splx(s); } for (pvp = pv_page_collectlist.tqh_first; pvp; pvp = npvp) { npvp = pvp->pvp_pgi.pgi_list.tqe_next; FREE(pvp, M_VMPVENT); } } __inline void pmap_enter_pv(pmap, va, pind) register pmap_t pmap; vm_offset_t va; u_int pind; { register struct pv_entry *pv, *npv; int s; if (!pmap_initialized) return; #ifdef DEBUG if (pmapdebug & PDB_ENTER) printf("pmap_enter_pv: pv %x: %x/%x/%x\n", pv, pv->pv_va, pv->pv_pmap, pv->pv_next); #endif pv = &pv_table[pind]; s = splimp(); if (pv->pv_pmap == NULL) { /* * No entries yet, use header as the first entry */ #ifdef DEBUG enter_stats.firstpv++; #endif pv->pv_va = va; pv->pv_pmap = pmap; pv->pv_next = NULL; } else { /* * There is at least one other VA mapping this page. * Place this entry after the header. */ #ifdef DEBUG for (npv = pv; npv; npv = npv->pv_next) if (pmap == npv->pv_pmap && va == npv->pv_va) panic("pmap_enter_pv: already in pv_tab"); #endif npv = pmap_alloc_pv(); npv->pv_va = va; npv->pv_pmap = pmap; npv->pv_next = pv->pv_next; pv->pv_next = npv; #ifdef DEBUG if (!npv->pv_next) enter_stats.secondpv++; #endif } splx(s); } __inline void pmap_remove_pv(pmap, va, pind) register pmap_t pmap; vm_offset_t va; u_int pind; { register struct pv_entry *pv, *npv; int s; /* * Remove from the PV table (raise IPL since we * may be called at interrupt time). */ pv = &pv_table[pind]; s = splimp(); /* * If it is the first entry on the list, it is actually * in the header and we must copy the following entry up * to the header. Otherwise we must search the list for * the entry. In either case we free the now unused entry. */ if (pmap == pv->pv_pmap && va == pv->pv_va) { npv = pv->pv_next; if (npv) { *pv = *npv; pmap_free_pv(npv); } else pv->pv_pmap = NULL; } else { for (npv = pv->pv_next; npv; pv = npv, npv = npv->pv_next) { if (pmap == npv->pv_pmap && va == npv->pv_va) break; } if (npv) { pv->pv_next = npv->pv_next; pmap_free_pv(npv); } } splx(s); } /* * Used to map a range of physical addresses into kernel * virtual address space. * * For now, VM is already on, we only need to map the * specified memory. */ vm_offset_t pmap_map(va, spa, epa, prot) vm_offset_t va, spa, epa; int prot; { #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_map(%x, %x, %x, %x)\n", va, spa, epa, prot); #endif while (spa < epa) { pmap_enter(kernel_pmap, va, spa, prot, FALSE); va += NBPG; spa += NBPG; } return va; } /* * Create and return a physical map. * * If the size specified for the map * is zero, the map is an actual physical * map, and may be referenced by the * hardware. * * If the size specified is non-zero, * the map will be used in software only, and * is bounded by that size. * * [ just allocate a ptd and mark it uninitialize -- should we track * with a table which process has which ptd? -wfj ] */ pmap_t pmap_create(size) vm_size_t size; { register pmap_t pmap; #ifdef DEBUG if (pmapdebug & (PDB_FOLLOW|PDB_CREATE)) printf("pmap_create(%x)\n", size); #endif /* * Software use map does not need a pmap */ if (size) return NULL; pmap = (pmap_t) malloc(sizeof *pmap, M_VMPMAP, M_WAITOK); bzero(pmap, sizeof(*pmap)); pmap_pinit(pmap); return pmap; } /* * Initialize a preallocated and zeroed pmap structure, * such as one in a vmspace structure. */ void pmap_pinit(pmap) register struct pmap *pmap; { #ifdef DEBUG if (pmapdebug & (PDB_FOLLOW|PDB_CREATE)) printf("pmap_pinit(%x)\n", pmap); #endif /* * No need to allocate page table space yet but we do need a * valid page directory table. */ pmap->pm_pdir = (pd_entry_t *) kmem_alloc(kernel_map, NBPG); /* wire in kernel global address entries */ bcopy(PTD + KPTDI, pmap->pm_pdir + KPTDI, NKPDE * sizeof(pd_entry_t)); /* install self-referential address mapping entry */ *(pmap->pm_pdir + PTDPTDI) = pmap_extract(kernel_pmap, (vm_offset_t)pmap->pm_pdir) | PG_V | PG_KW; pmap->pm_count = 1; simple_lock_init(&pmap->pm_lock); } /* * Retire the given physical map from service. * Should only be called if the map contains * no valid mappings. */ void pmap_destroy(pmap) register pmap_t pmap; { int count; if (pmap == NULL) return; #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_destroy(%x)\n", pmap); #endif simple_lock(&pmap->pm_lock); count = --pmap->pm_count; simple_unlock(&pmap->pm_lock); if (count == 0) { pmap_release(pmap); free((caddr_t)pmap, M_VMPMAP); } } /* * Release any resources held by the given physical map. * Called when a pmap initialized by pmap_pinit is being released. * Should only be called if the map contains no valid mappings. */ void pmap_release(pmap) register struct pmap *pmap; { #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_release(%x)\n", pmap); #endif #ifdef DIAGNOSTICx /* sometimes 1, sometimes 0; could rearrange pmap_destroy */ if (pmap->pm_count != 1) panic("pmap_release count"); #endif kmem_free(kernel_map, (vm_offset_t)pmap->pm_pdir, NBPG); } /* * Add a reference to the specified pmap. */ void pmap_reference(pmap) pmap_t pmap; { if (pmap == NULL) return; #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_reference(%x)", pmap); #endif simple_lock(&pmap->pm_lock); pmap->pm_count++; simple_unlock(&pmap->pm_lock); } void pmap_activate(pmap, pcb) pmap_t pmap; struct pcb *pcb; { if (pmap /*&& pmap->pm_pdchanged */) { pcb->pcb_cr3 = pmap_extract(kernel_pmap, (vm_offset_t)pmap->pm_pdir); if (pmap == &curproc->p_vmspace->vm_pmap) lcr3(pcb->pcb_cr3); pmap->pm_pdchanged = FALSE; } } void pmap_deactivate(pmap, pcb) pmap_t pmap; struct pcb *pcb; { } /* * Remove the given range of addresses from the specified map. * * It is assumed that the start and end are properly * rounded to the page size. */ void pmap_remove(pmap, sva, eva) struct pmap *pmap; register vm_offset_t sva, eva; { register pt_entry_t *pte; vm_offset_t pa; u_int pind; int flush = 0; sva &= PG_FRAME; eva &= PG_FRAME; /* * We need to acquire a pointer to a page table page before entering * the following loop. */ while (sva < eva) { pte = pmap_pte(pmap, sva); if (pte) break; sva = (sva & PD_MASK) + NBPD; } while (sva < eva) { /* only check once in a while */ if ((sva & PT_MASK) == 0) { if (!pmap_pde_v(pmap_pde(pmap, sva))) { /* We can race ahead here, to the next pde. */ sva += NBPD; pte += i386_btop(NBPD); continue; } } if (!pmap_pte_v(pte)) { #ifdef __GNUC__ /* * Scan ahead in a tight loop for the next used PTE in * this page. We don't scan the whole region here * because we don't want to zero-fill unused page table * pages. */ int n, m; n = min(eva - sva, NBPD - (sva & PT_MASK)) >> PGSHIFT; __asm __volatile( "cld\n\trepe\n\tscasl\n\tje 1f\n\tincl %1\n\t1:" : "=D" (pte), "=c" (m) : "0" (pte), "1" (n), "a" (0)); sva += (n - m) << PGSHIFT; if (!m) continue; /* Overshot. */ --pte; #else goto next; #endif } flush = 1; /* * Update statistics */ if (pmap_pte_w(pte)) pmap->pm_stats.wired_count--; pmap->pm_stats.resident_count--; pa = pmap_pte_pa(pte); /* * Invalidate the PTEs. * XXX: should cluster them up and invalidate as many * as possible at once. */ #ifdef DEBUG if (pmapdebug & PDB_REMOVE) printf("remove: inv pte at %x(%x) ", pte, *pte); #endif #ifdef needednotdone reduce wiring count on page table pages as references drop #endif if ((pind = pmap_page_index(pa)) != -1) { pmap_attributes[pind] |= *pte & (PG_M | PG_U); pmap_remove_pv(pmap, sva, pind); } *pte = 0; next: sva += NBPG; pte++; } if (flush) pmap_update(); } /* * Routine: pmap_remove_all * Function: * Removes this physical page from * all physical maps in which it resides. * Reflects back modify bits to the pager. */ void pmap_remove_all(pa) vm_offset_t pa; { struct pv_entry *ph, *pv, *npv; register pmap_t pmap; register pt_entry_t *pte; u_int pind; int s; #ifdef DEBUG if (pmapdebug & (PDB_FOLLOW|PDB_REMOVE|PDB_PROTECT)) printf("pmap_remove_all(%x)", pa); /*pmap_pvdump(pa);*/ #endif if ((pind = pmap_page_index(pa)) == -1) return; pv = ph = &pv_table[pind]; s = splimp(); if (ph->pv_pmap == NULL) { splx(s); return; } while (pv) { pmap = pv->pv_pmap; pte = pmap_pte(pmap, pv->pv_va); #ifdef DEBUG if (!pte || !pmap_pte_v(pte) || pmap_pte_pa(pte) != pa) panic("pmap_remove_all: bad mapping"); #endif /* * Update statistics */ if (pmap_pte_w(pte)) pmap->pm_stats.wired_count--; pmap->pm_stats.resident_count--; /* * Invalidate the PTEs. * XXX: should cluster them up and invalidate as many * as possible at once. */ #ifdef DEBUG if (pmapdebug & PDB_REMOVE) printf("remove: inv pte at %x(%x) ", pte, *pte); #endif #ifdef needednotdone reduce wiring count on page table pages as references drop #endif /* * Update saved attributes for managed page */ pmap_attributes[pind] |= *pte & (PG_M | PG_U); *pte = 0; npv = pv->pv_next; if (pv == ph) ph->pv_pmap = NULL; else pmap_free_pv(pv); pv = npv; } splx(s); pmap_update(); } /* * Set the physical protection on the * specified range of this map as requested. */ void pmap_protect(pmap, sva, eva, prot) register pmap_t pmap; vm_offset_t sva, eva; vm_prot_t prot; { register pt_entry_t *pte; register int i386prot; int flush = 0; #ifdef DEBUG if (pmapdebug & (PDB_FOLLOW|PDB_PROTECT)) printf("pmap_protect(%x, %x, %x, %x)", pmap, sva, eva, prot); #endif if ((prot & VM_PROT_READ) == VM_PROT_NONE) { pmap_remove(pmap, sva, eva); return; } if (prot & VM_PROT_WRITE) return; sva &= PG_FRAME; eva &= PG_FRAME; /* * We need to acquire a pointer to a page table page before entering * the following loop. */ while (sva < eva) { pte = pmap_pte(pmap, sva); if (pte) break; sva = (sva & PD_MASK) + NBPD; } while (sva < eva) { /* only check once in a while */ if ((sva & PT_MASK) == 0) { if (!pmap_pde_v(pmap_pde(pmap, sva))) { /* We can race ahead here, to the next pde. */ sva += NBPD; pte += i386_btop(NBPD); continue; } } if (!pmap_pte_v(pte)) { #ifdef __GNUC__ /* * Scan ahead in a tight loop for the next used PTE in * this page. We don't scan the whole region here * because we don't want to zero-fill unused page table * pages. */ int n, m; n = min(eva - sva, NBPD - (sva & PT_MASK)) >> PGSHIFT; __asm __volatile( "cld\n\trepe\n\tscasl\n\tje 1f\n\tincl %1\n\t1:" : "=D" (pte), "=c" (m) : "0" (pte), "1" (n), "a" (0)); sva += (n - m) << PGSHIFT; if (!m) continue; /* Overshot. */ --pte; #else goto next; #endif } flush = 1; i386prot = protection_codes[prot]; if (sva < VM_MAXUSER_ADDRESS) /* see also pmap_enter() */ i386prot |= PG_u; else if (sva < VM_MAX_ADDRESS) i386prot |= PG_u | PG_RW; pmap_pte_set_prot(pte, i386prot); next: sva += NBPG; pte++; } if (flush) pmap_update(); } /* * Insert the given physical page (p) at * the specified virtual address (v) in the * target physical map with the protection requested. * * If specified, the page will be wired down, meaning * that the related pte can not be reclaimed. * * NB: This is the only routine which MAY NOT lazy-evaluate * or lose information. That is, this routine must actually * insert this page into the given map NOW. */ void pmap_enter(pmap, va, pa, prot, wired) register pmap_t pmap; vm_offset_t va; register vm_offset_t pa; vm_prot_t prot; boolean_t wired; { register pt_entry_t *pte; register pt_entry_t npte; u_int pind; int flush = 0; boolean_t cacheable; #ifdef DEBUG if (pmapdebug & (PDB_FOLLOW|PDB_ENTER)) printf("pmap_enter(%x, %x, %x, %x, %x)", pmap, va, pa, prot, wired); #endif if (pmap == NULL) return; if (va >= VM_MAX_KERNEL_ADDRESS) panic("pmap_enter: too big"); /* also, should not muck with PTD va! */ #ifdef DEBUG if (pmap == kernel_pmap) enter_stats.kernel++; else enter_stats.user++; #endif /* * Page Directory table entry not valid, we need a new PT page */ pte = pmap_pte(pmap, va); if (!pte) panic("ptdi %x", pmap->pm_pdir[PTDPTDI]); #ifdef DEBUG if (pmapdebug & PDB_ENTER) printf("enter: pte %x, *pte %x ", pte, *pte); #endif if (pmap_pte_v(pte)) { register vm_offset_t opa; /* * Check for wiring change and adjust statistics. */ if (wired && !pmap_pte_w(pte) || !wired && pmap_pte_w(pte)) { /* * We don't worry about wiring PT pages as they remain * resident as long as there are valid mappings in them. * Hence, if a user page is wired, the PT page will be also. */ #ifdef DEBUG if (pmapdebug & PDB_ENTER) printf("enter: wiring change -> %x ", wired); #endif if (wired) pmap->pm_stats.wired_count++; else pmap->pm_stats.wired_count--; #ifdef DEBUG enter_stats.wchange++; #endif } flush = 1; opa = pmap_pte_pa(pte); /* * Mapping has not changed, must be protection or wiring change. */ if (opa == pa) { #ifdef DEBUG enter_stats.pwchange++; #endif goto validate; } /* * Mapping has changed, invalidate old range and fall through to * handle validating new mapping. */ #ifdef DEBUG if (pmapdebug & PDB_ENTER) printf("enter: removing old mapping %x pa %x ", va, opa); #endif if ((pind = pmap_page_index(opa)) != -1) { pmap_attributes[pind] |= *pte & (PG_M | PG_U); pmap_remove_pv(pmap, va, pind); } #ifdef DEBUG enter_stats.mchange++; #endif } else { /* * Increment counters */ pmap->pm_stats.resident_count++; if (wired) pmap->pm_stats.wired_count++; } /* * Enter on the PV list if part of our managed memory */ if ((pind = pmap_page_index(pa)) != -1) { #ifdef DEBUG enter_stats.managed++; #endif pmap_enter_pv(pmap, va, pind); cacheable = TRUE; } else if (pmap_initialized) { #ifdef DEBUG enter_stats.unmanaged++; #endif /* * Assumption: if it is not part of our managed memory * then it must be device memory which may be volatile. */ cacheable = FALSE; } validate: /* * Now validate mapping with desired protection/wiring. * Assume uniform modified and referenced status for all * I386 pages in a MACH page. */ npte = (pa & PG_FRAME) | protection_codes[prot] | PG_V; if (wired) npte |= PG_W; if (va < VM_MAXUSER_ADDRESS) /* i.e. below USRSTACK */ npte |= PG_u; else if (va < VM_MAX_ADDRESS) /* * Page tables need to be user RW, for some reason, and the * user area must be writable too. Anything above * VM_MAXUSER_ADDRESS is protected from user access by * the user data and code segment descriptors, so this is OK. */ npte |= PG_u | PG_RW; #ifdef DEBUG if (pmapdebug & PDB_ENTER) printf("enter: new pte value %x ", npte); #endif *pte = npte; if (flush) pmap_update(); } /* * pmap_page_protect: * * Lower the permission for all mappings to a given page. */ void pmap_page_protect(phys, prot) vm_offset_t phys; vm_prot_t prot; { switch (prot) { case VM_PROT_READ: case VM_PROT_READ|VM_PROT_EXECUTE: pmap_copy_on_write(phys); break; case VM_PROT_ALL: break; default: pmap_remove_all(phys); break; } } /* * Routine: pmap_change_wiring * Function: Change the wiring attribute for a map/virtual-address * pair. * In/out conditions: * The mapping must already exist in the pmap. */ void pmap_change_wiring(pmap, va, wired) register pmap_t pmap; vm_offset_t va; boolean_t wired; { register pt_entry_t *pte; #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_change_wiring(%x, %x, %x)", pmap, va, wired); #endif pte = pmap_pte(pmap, va); if (!pte) return; #ifdef DEBUG /* * Page not valid. Should this ever happen? * Just continue and change wiring anyway. */ if (!pmap_pte_v(pte)) { if (pmapdebug & PDB_PARANOIA) printf("pmap_change_wiring: invalid PTE for %x ", va); } #endif if (wired && !pmap_pte_w(pte) || !wired && pmap_pte_w(pte)) { if (wired) pmap->pm_stats.wired_count++; else pmap->pm_stats.wired_count--; pmap_pte_set_w(pte, wired); } } /* * Routine: pmap_pte * Function: * Extract the page table entry associated * with the given map/virtual_address pair. */ pt_entry_t * pmap_pte(pmap, va) register pmap_t pmap; vm_offset_t va; { pt_entry_t *ptp; #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_pte(%x, %x) ->\n", pmap, va); #endif if (!pmap || !pmap_pde_v(pmap_pde(pmap, va))) return NULL; if ((pmap->pm_pdir[PTDPTDI] & PG_FRAME) == (PTDpde & PG_FRAME) || pmap == kernel_pmap) /* current address space or kernel */ ptp = PTmap; else { /* alternate address space */ if ((pmap->pm_pdir[PTDPTDI] & PG_FRAME) != (APTDpde & PG_FRAME)) { APTDpde = pmap->pm_pdir[PTDPTDI]; pmap_update(); } ptp = APTmap; } return ptp + i386_btop(va); } /* * Routine: pmap_extract * Function: * Extract the physical page address associated * with the given map/virtual_address pair. */ vm_offset_t pmap_extract(pmap, va) register pmap_t pmap; vm_offset_t va; { register pt_entry_t *pte; register vm_offset_t pa; #ifdef DEBUGx if (pmapdebug & PDB_FOLLOW) printf("pmap_extract(%x, %x) -> ", pmap, va); #endif pte = pmap_pte(pmap, va); if (!pte) return NULL; if (!pmap_pte_v(pte)) return NULL; pa = pmap_pte_pa(pte); #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("%x\n", pa); #endif return pa | (va & ~PG_FRAME); } /* * Copy the range specified by src_addr/len * from the source map to the range dst_addr/len * in the destination map. * * This routine is only advisory and need not do anything. */ void pmap_copy(dst_pmap, src_pmap, dst_addr, len, src_addr) pmap_t dst_pmap, src_pmap; vm_offset_t dst_addr, src_addr; vm_size_t len; { #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_copy(%x, %x, %x, %x, %x)", dst_pmap, src_pmap, dst_addr, len, src_addr); #endif } /* * Routine: pmap_collect * Function: * Garbage collects the physical map system for * pages which are no longer used. * Success need not be guaranteed -- that is, there * may well be pages which are not referenced, but * others may be collected. * Usage: * Called by the pageout daemon when pages are scarce. * [ needs to be written -wfj ] XXXX */ void pmap_collect(pmap) pmap_t pmap; { register vm_offset_t pa; register struct pv_entry *pv; register pt_entry_t *pte; vm_offset_t kpa; int s; #ifdef DEBUG printf("pmap_collect(%x) ", pmap); #endif if (pmap != kernel_pmap) return; } #if 0 void pmap_dump_pvlist(phys, m) vm_offset_t phys; char *m; { register struct pv_entry *pv; if (!pmap_initialized) return; printf("%s %08x:", m, phys); pv = &pv_table[pmap_page_index(phys)]; if (pv->pv_pmap == NULL) { printf(" no mappings\n"); return; } for (; pv; pv = pv->pv_next) printf(" pmap %08x va %08x", pv->pv_pmap, pv->pv_va); printf("\n"); } #else #define pmap_dump_pvlist(a,b) #endif /* * pmap_zero_page zeros the specified by mapping it into * virtual memory and using bzero to clear its contents. */ void pmap_zero_page(phys) register vm_offset_t phys; { #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_zero_page(%x)", phys); #endif pmap_dump_pvlist(phys, "pmap_zero_page: phys"); *CMAP2 = (phys & PG_FRAME) | PG_V | PG_KW /*| PG_N*/; pmap_update(); bzero(CADDR2, NBPG); } /* * pmap_copy_page copies the specified page by mapping * it into virtual memory and using bcopy to copy its * contents. */ void pmap_copy_page(src, dst) register vm_offset_t src, dst; { #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_copy_page(%x, %x)", src, dst); #endif pmap_dump_pvlist(src, "pmap_copy_page: src"); pmap_dump_pvlist(dst, "pmap_copy_page: dst"); *CMAP1 = (src & PG_FRAME) | PG_V | PG_KW; *CMAP2 = (dst & PG_FRAME) | PG_V | PG_KW /*| PG_N*/; pmap_update(); bcopy(CADDR1, CADDR2, NBPG); } /* * Routine: pmap_pageable * Function: * Make the specified pages (by pmap, offset) * pageable (or not) as requested. * * A page which is not pageable may not take * a fault; therefore, its page table entry * must remain valid for the duration. * * This routine is merely advisory; pmap_enter * will specify that these pages are to be wired * down (or not) as appropriate. */ void pmap_pageable(pmap, sva, eva, pageable) pmap_t pmap; vm_offset_t sva, eva; boolean_t pageable; { #ifdef DEBUG if (pmapdebug & PDB_FOLLOW) printf("pmap_pageable(%x, %x, %x, %x)", pmap, sva, eva, pageable); #endif /* * If we are making a PT page pageable then all valid * mappings must be gone from that page. Hence it should * be all zeros and there is no need to clean it. * Assumptions: * - we are called with only one page at a time * - PT pages have only one pv_table entry */ if (pmap == kernel_pmap && pageable && sva + NBPG == eva) { register vm_offset_t pa; register pt_entry_t *pte; #ifdef DEBUG u_int pind; register struct pv_entry *pv; if ((pmapdebug & (PDB_FOLLOW|PDB_PTPAGE)) == PDB_PTPAGE) printf("pmap_pageable(%x, %x, %x, %x)", pmap, sva, eva, pageable); #endif pte = pmap_pte(pmap, sva); if (!pte) return; if (!pmap_pte_v(pte)) return; pa = pmap_pte_pa(pte); #ifdef DEBUG if ((pind = pmap_page_index(pa)) == -1) return; pv = &pv_table[pind]; if (pv->pv_va != sva || pv->pv_next) { printf("pmap_pageable: bad PT page va %x next %x\n", pv->pv_va, pv->pv_next); return; } #endif /* * Mark it unmodified to avoid pageout */ pmap_clear_modify(pa); #ifdef needsomethinglikethis if (pmapdebug & PDB_PTPAGE) printf("pmap_pageable: PT page %x(%x) unmodified\n", sva, *pmap_pte(pmap, sva)); if (pmapdebug & PDB_WIRING) pmap_check_wiring("pageable", sva); #endif } } /* * Miscellaneous support routines follow */ i386_protection_init() { protection_codes[VM_PROT_NONE | VM_PROT_NONE | VM_PROT_NONE] = 0; protection_codes[VM_PROT_NONE | VM_PROT_NONE | VM_PROT_EXECUTE] = protection_codes[VM_PROT_NONE | VM_PROT_READ | VM_PROT_NONE] = protection_codes[VM_PROT_NONE | VM_PROT_READ | VM_PROT_EXECUTE] = PG_RO; protection_codes[VM_PROT_WRITE | VM_PROT_NONE | VM_PROT_NONE] = protection_codes[VM_PROT_WRITE | VM_PROT_NONE | VM_PROT_EXECUTE] = protection_codes[VM_PROT_WRITE | VM_PROT_READ | VM_PROT_NONE] = protection_codes[VM_PROT_WRITE | VM_PROT_READ | VM_PROT_EXECUTE] = PG_RW; } boolean_t pmap_testbit(pa, setbits) register vm_offset_t pa; int setbits; { register struct pv_entry *pv; register pt_entry_t *pte; u_int pind; int s; if ((pind = pmap_page_index(pa)) == -1) return FALSE; pv = &pv_table[pind]; s = splimp(); /* * Check saved info first */ if (pmap_attributes[pind] & setbits) { splx(s); return TRUE; } /* * Not found, check current mappings returning * immediately if found. */ if (pv->pv_pmap != NULL) { for (; pv; pv = pv->pv_next) { pte = pmap_pte(pv->pv_pmap, pv->pv_va); if (*pte & setbits) { splx(s); return TRUE; } } } splx(s); return FALSE; } /* * Modify pte bits for all ptes corresponding to the given physical address. * We use `maskbits' rather than `clearbits' because we're always passing * constants and the latter would require an extra inversion at run-time. */ void pmap_changebit(pa, setbits, maskbits) register vm_offset_t pa; int setbits, maskbits; { register struct pv_entry *pv; register pt_entry_t *pte; vm_offset_t va; u_int pind; int s; #ifdef DEBUG if (pmapdebug & PDB_BITS) printf("pmap_changebit(%x, %x, %x)", pa, setbits, ~maskbits); #endif if ((pind = pmap_page_index(pa)) == -1) return; pv = &pv_table[pind]; s = splimp(); /* * Clear saved attributes (modify, reference) */ if (~maskbits) pmap_attributes[pind] &= maskbits; /* * Loop over all current mappings setting/clearing as appropos * If setting RO do we need to clear the VAC? */ if (pv->pv_pmap != NULL) { for (; pv; pv = pv->pv_next) { va = pv->pv_va; /* * XXX don't write protect pager mappings */ if ((PG_RO && setbits == PG_RO) || (PG_RW && maskbits == ~PG_RW)) { extern vm_offset_t pager_sva, pager_eva; if (va >= pager_sva && va < pager_eva) continue; } pte = pmap_pte(pv->pv_pmap, va); *pte = (*pte & maskbits) | setbits; } pmap_update(); } splx(s); } #ifdef DEBUG pmap_pvdump(pa) vm_offset_t pa; { register struct pv_entry *pv; printf("pa %x", pa); for (pv = &pv_table[pmap_page_index(pa)]; pv; pv = pv->pv_next) { printf(" -> pmap %x, va %x", pv->pv_pmap, pv->pv_va); pads(pv->pv_pmap); } printf(" "); } #ifdef notyet pmap_check_wiring(str, va) char *str; vm_offset_t va; { vm_map_entry_t entry; register int count, *pte; va = trunc_page(va); if (!pmap_pde_v(pmap_pde(kernel_pmap, va)) || !pmap_pte_v(pmap_pte(kernel_pmap, va))) return; if (!vm_map_lookup_entry(pt_map, va, &entry)) { printf("wired_check: entry for %x not found\n", va); return; } count = 0; for (pte = (int *)va; pte < (int *)(va + NBPG); pte++) if (*pte) count++; if (entry->wired_count != count) printf("*%s*: %x: w%d/a%d\n", str, va, entry->wired_count, count); } #endif /* print address space of pmap*/ pads(pm) pmap_t pm; { unsigned va, i, j; register pt_entry_t *pte; if (pm == kernel_pmap) return; for (i = 0; i < 1024; i++) if (pmap_pde_v(&pm->pm_pdir[i])) for (j = 0; j < 1024 ; j++) { va = (i << PDSHIFT) | (j << PGSHIFT); if (pm == kernel_pmap && va < VM_MIN_KERNEL_ADDRESS) continue; if (pm != kernel_pmap && va > VM_MAX_ADDRESS) continue; pte = pmap_pte(pm, va); if (pmap_pte_v(pte)) printf("%x:%x ", va, *pte); } } #endif