device_pager.c revision 1541
11541Srgrimes/* 21541Srgrimes * Copyright (c) 1990 University of Utah. 31541Srgrimes * Copyright (c) 1991, 1993 41541Srgrimes * The Regents of the University of California. All rights reserved. 51541Srgrimes * 61541Srgrimes * This code is derived from software contributed to Berkeley by 71541Srgrimes * the Systems Programming Group of the University of Utah Computer 81541Srgrimes * Science Department. 91541Srgrimes * 101541Srgrimes * Redistribution and use in source and binary forms, with or without 111541Srgrimes * modification, are permitted provided that the following conditions 121541Srgrimes * are met: 131541Srgrimes * 1. Redistributions of source code must retain the above copyright 141541Srgrimes * notice, this list of conditions and the following disclaimer. 151541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 161541Srgrimes * notice, this list of conditions and the following disclaimer in the 171541Srgrimes * documentation and/or other materials provided with the distribution. 181541Srgrimes * 3. All advertising materials mentioning features or use of this software 191541Srgrimes * must display the following acknowledgement: 201541Srgrimes * This product includes software developed by the University of 211541Srgrimes * California, Berkeley and its contributors. 221541Srgrimes * 4. Neither the name of the University nor the names of its contributors 231541Srgrimes * may be used to endorse or promote products derived from this software 241541Srgrimes * without specific prior written permission. 251541Srgrimes * 261541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 271541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 281541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 291541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 301541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 311541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 321541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 331541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 341541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 351541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 361541Srgrimes * SUCH DAMAGE. 371541Srgrimes * 381541Srgrimes * @(#)device_pager.c 8.5 (Berkeley) 1/12/94 391541Srgrimes */ 401541Srgrimes 411541Srgrimes/* 421541Srgrimes * Page to/from special files. 431541Srgrimes */ 441541Srgrimes 451541Srgrimes#include <sys/param.h> 461541Srgrimes#include <sys/systm.h> 471541Srgrimes#include <sys/conf.h> 481541Srgrimes#include <sys/mman.h> 491541Srgrimes#include <sys/malloc.h> 501541Srgrimes 511541Srgrimes#include <vm/vm.h> 521541Srgrimes#include <vm/vm_kern.h> 531541Srgrimes#include <vm/vm_page.h> 541541Srgrimes#include <vm/device_pager.h> 551541Srgrimes 561541Srgrimesstruct pagerlst dev_pager_list; /* list of managed devices */ 571541Srgrimesstruct pglist dev_pager_fakelist; /* list of available vm_page_t's */ 581541Srgrimes 591541Srgrimes#ifdef DEBUG 601541Srgrimesint dpagerdebug = 0; 611541Srgrimes#define DDB_FOLLOW 0x01 621541Srgrimes#define DDB_INIT 0x02 631541Srgrimes#define DDB_ALLOC 0x04 641541Srgrimes#define DDB_FAIL 0x08 651541Srgrimes#endif 661541Srgrimes 671541Srgrimesstatic vm_pager_t dev_pager_alloc 681541Srgrimes __P((caddr_t, vm_size_t, vm_prot_t, vm_offset_t)); 691541Srgrimesstatic void dev_pager_dealloc __P((vm_pager_t)); 701541Srgrimesstatic int dev_pager_getpage 711541Srgrimes __P((vm_pager_t, vm_page_t *, int, boolean_t)); 721541Srgrimesstatic boolean_t dev_pager_haspage __P((vm_pager_t, vm_offset_t)); 731541Srgrimesstatic void dev_pager_init __P((void)); 741541Srgrimesstatic int dev_pager_putpage 751541Srgrimes __P((vm_pager_t, vm_page_t *, int, boolean_t)); 761541Srgrimesstatic vm_page_t dev_pager_getfake __P((vm_offset_t)); 771541Srgrimesstatic void dev_pager_putfake __P((vm_page_t)); 781541Srgrimes 791541Srgrimesstruct pagerops devicepagerops = { 801541Srgrimes dev_pager_init, 811541Srgrimes dev_pager_alloc, 821541Srgrimes dev_pager_dealloc, 831541Srgrimes dev_pager_getpage, 841541Srgrimes dev_pager_putpage, 851541Srgrimes dev_pager_haspage, 861541Srgrimes vm_pager_clusternull 871541Srgrimes}; 881541Srgrimes 891541Srgrimesstatic void 901541Srgrimesdev_pager_init() 911541Srgrimes{ 921541Srgrimes#ifdef DEBUG 931541Srgrimes if (dpagerdebug & DDB_FOLLOW) 941541Srgrimes printf("dev_pager_init()\n"); 951541Srgrimes#endif 961541Srgrimes TAILQ_INIT(&dev_pager_list); 971541Srgrimes TAILQ_INIT(&dev_pager_fakelist); 981541Srgrimes} 991541Srgrimes 1001541Srgrimesstatic vm_pager_t 1011541Srgrimesdev_pager_alloc(handle, size, prot, foff) 1021541Srgrimes caddr_t handle; 1031541Srgrimes vm_size_t size; 1041541Srgrimes vm_prot_t prot; 1051541Srgrimes vm_offset_t foff; 1061541Srgrimes{ 1071541Srgrimes dev_t dev; 1081541Srgrimes vm_pager_t pager; 1091541Srgrimes int (*mapfunc)(); 1101541Srgrimes vm_object_t object; 1111541Srgrimes dev_pager_t devp; 1121541Srgrimes int npages, off; 1131541Srgrimes 1141541Srgrimes#ifdef DEBUG 1151541Srgrimes if (dpagerdebug & DDB_FOLLOW) 1161541Srgrimes printf("dev_pager_alloc(%x, %x, %x, %x)\n", 1171541Srgrimes handle, size, prot, foff); 1181541Srgrimes#endif 1191541Srgrimes#ifdef DIAGNOSTIC 1201541Srgrimes /* 1211541Srgrimes * Pageout to device, should never happen. 1221541Srgrimes */ 1231541Srgrimes if (handle == NULL) 1241541Srgrimes panic("dev_pager_alloc called"); 1251541Srgrimes#endif 1261541Srgrimes 1271541Srgrimes /* 1281541Srgrimes * Make sure this device can be mapped. 1291541Srgrimes */ 1301541Srgrimes dev = (dev_t)handle; 1311541Srgrimes mapfunc = cdevsw[major(dev)].d_mmap; 1321541Srgrimes if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop) 1331541Srgrimes return(NULL); 1341541Srgrimes 1351541Srgrimes /* 1361541Srgrimes * Offset should be page aligned. 1371541Srgrimes */ 1381541Srgrimes if (foff & PAGE_MASK) 1391541Srgrimes return(NULL); 1401541Srgrimes 1411541Srgrimes /* 1421541Srgrimes * Check that the specified range of the device allows the 1431541Srgrimes * desired protection. 1441541Srgrimes * 1451541Srgrimes * XXX assumes VM_PROT_* == PROT_* 1461541Srgrimes */ 1471541Srgrimes npages = atop(round_page(size)); 1481541Srgrimes for (off = foff; npages--; off += PAGE_SIZE) 1491541Srgrimes if ((*mapfunc)(dev, off, (int)prot) == -1) 1501541Srgrimes return(NULL); 1511541Srgrimes 1521541Srgrimes /* 1531541Srgrimes * Look up pager, creating as necessary. 1541541Srgrimes */ 1551541Srgrimestop: 1561541Srgrimes pager = vm_pager_lookup(&dev_pager_list, handle); 1571541Srgrimes if (pager == NULL) { 1581541Srgrimes /* 1591541Srgrimes * Allocate and initialize pager structs 1601541Srgrimes */ 1611541Srgrimes pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK); 1621541Srgrimes if (pager == NULL) 1631541Srgrimes return(NULL); 1641541Srgrimes devp = (dev_pager_t)malloc(sizeof *devp, M_VMPGDATA, M_WAITOK); 1651541Srgrimes if (devp == NULL) { 1661541Srgrimes free((caddr_t)pager, M_VMPAGER); 1671541Srgrimes return(NULL); 1681541Srgrimes } 1691541Srgrimes pager->pg_handle = handle; 1701541Srgrimes pager->pg_ops = &devicepagerops; 1711541Srgrimes pager->pg_type = PG_DEVICE; 1721541Srgrimes pager->pg_flags = 0; 1731541Srgrimes pager->pg_data = devp; 1741541Srgrimes TAILQ_INIT(&devp->devp_pglist); 1751541Srgrimes /* 1761541Srgrimes * Allocate object and associate it with the pager. 1771541Srgrimes */ 1781541Srgrimes object = devp->devp_object = vm_object_allocate(0); 1791541Srgrimes vm_object_enter(object, pager); 1801541Srgrimes vm_object_setpager(object, pager, (vm_offset_t)0, FALSE); 1811541Srgrimes /* 1821541Srgrimes * Finally, put it on the managed list so other can find it. 1831541Srgrimes * First we re-lookup in case someone else beat us to this 1841541Srgrimes * point (due to blocking in the various mallocs). If so, 1851541Srgrimes * we free everything and start over. 1861541Srgrimes */ 1871541Srgrimes if (vm_pager_lookup(&dev_pager_list, handle)) { 1881541Srgrimes free((caddr_t)devp, M_VMPGDATA); 1891541Srgrimes free((caddr_t)pager, M_VMPAGER); 1901541Srgrimes goto top; 1911541Srgrimes } 1921541Srgrimes TAILQ_INSERT_TAIL(&dev_pager_list, pager, pg_list); 1931541Srgrimes#ifdef DEBUG 1941541Srgrimes if (dpagerdebug & DDB_ALLOC) { 1951541Srgrimes printf("dev_pager_alloc: pager %x devp %x object %x\n", 1961541Srgrimes pager, devp, object); 1971541Srgrimes vm_object_print(object, FALSE); 1981541Srgrimes } 1991541Srgrimes#endif 2001541Srgrimes } else { 2011541Srgrimes /* 2021541Srgrimes * vm_object_lookup() gains a reference and also 2031541Srgrimes * removes the object from the cache. 2041541Srgrimes */ 2051541Srgrimes object = vm_object_lookup(pager); 2061541Srgrimes#ifdef DIAGNOSTIC 2071541Srgrimes devp = (dev_pager_t)pager->pg_data; 2081541Srgrimes if (object != devp->devp_object) 2091541Srgrimes panic("dev_pager_setup: bad object"); 2101541Srgrimes#endif 2111541Srgrimes } 2121541Srgrimes return(pager); 2131541Srgrimes} 2141541Srgrimes 2151541Srgrimesstatic void 2161541Srgrimesdev_pager_dealloc(pager) 2171541Srgrimes vm_pager_t pager; 2181541Srgrimes{ 2191541Srgrimes dev_pager_t devp; 2201541Srgrimes vm_object_t object; 2211541Srgrimes vm_page_t m; 2221541Srgrimes 2231541Srgrimes#ifdef DEBUG 2241541Srgrimes if (dpagerdebug & DDB_FOLLOW) 2251541Srgrimes printf("dev_pager_dealloc(%x)\n", pager); 2261541Srgrimes#endif 2271541Srgrimes TAILQ_REMOVE(&dev_pager_list, pager, pg_list); 2281541Srgrimes /* 2291541Srgrimes * Get the object. 2301541Srgrimes * Note: cannot use vm_object_lookup since object has already 2311541Srgrimes * been removed from the hash chain. 2321541Srgrimes */ 2331541Srgrimes devp = (dev_pager_t)pager->pg_data; 2341541Srgrimes object = devp->devp_object; 2351541Srgrimes#ifdef DEBUG 2361541Srgrimes if (dpagerdebug & DDB_ALLOC) 2371541Srgrimes printf("dev_pager_dealloc: devp %x object %x\n", devp, object); 2381541Srgrimes#endif 2391541Srgrimes /* 2401541Srgrimes * Free up our fake pages. 2411541Srgrimes */ 2421541Srgrimes while ((m = devp->devp_pglist.tqh_first) != NULL) { 2431541Srgrimes TAILQ_REMOVE(&devp->devp_pglist, m, pageq); 2441541Srgrimes dev_pager_putfake(m); 2451541Srgrimes } 2461541Srgrimes free((caddr_t)devp, M_VMPGDATA); 2471541Srgrimes free((caddr_t)pager, M_VMPAGER); 2481541Srgrimes} 2491541Srgrimes 2501541Srgrimesstatic int 2511541Srgrimesdev_pager_getpage(pager, mlist, npages, sync) 2521541Srgrimes vm_pager_t pager; 2531541Srgrimes vm_page_t *mlist; 2541541Srgrimes int npages; 2551541Srgrimes boolean_t sync; 2561541Srgrimes{ 2571541Srgrimes register vm_object_t object; 2581541Srgrimes vm_offset_t offset, paddr; 2591541Srgrimes vm_page_t page; 2601541Srgrimes dev_t dev; 2611541Srgrimes int (*mapfunc)(), prot; 2621541Srgrimes vm_page_t m; 2631541Srgrimes 2641541Srgrimes#ifdef DEBUG 2651541Srgrimes if (dpagerdebug & DDB_FOLLOW) 2661541Srgrimes printf("dev_pager_getpage(%x, %x, %x, %x)\n", 2671541Srgrimes pager, mlist, npages, sync); 2681541Srgrimes#endif 2691541Srgrimes 2701541Srgrimes if (npages != 1) 2711541Srgrimes panic("dev_pager_getpage: cannot handle multiple pages"); 2721541Srgrimes m = *mlist; 2731541Srgrimes 2741541Srgrimes object = m->object; 2751541Srgrimes dev = (dev_t)pager->pg_handle; 2761541Srgrimes offset = m->offset + object->paging_offset; 2771541Srgrimes prot = PROT_READ; /* XXX should pass in? */ 2781541Srgrimes mapfunc = cdevsw[major(dev)].d_mmap; 2791541Srgrimes#ifdef DIAGNOSTIC 2801541Srgrimes if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop) 2811541Srgrimes panic("dev_pager_getpage: no map function"); 2821541Srgrimes#endif 2831541Srgrimes paddr = pmap_phys_address((*mapfunc)(dev, (int)offset, prot)); 2841541Srgrimes#ifdef DIAGNOSTIC 2851541Srgrimes if (paddr == -1) 2861541Srgrimes panic("dev_pager_getpage: map function returns error"); 2871541Srgrimes#endif 2881541Srgrimes /* 2891541Srgrimes * Replace the passed in page with our own fake page and free 2901541Srgrimes * up the original. 2911541Srgrimes */ 2921541Srgrimes page = dev_pager_getfake(paddr); 2931541Srgrimes TAILQ_INSERT_TAIL(&((dev_pager_t)pager->pg_data)->devp_pglist, page, 2941541Srgrimes pageq); 2951541Srgrimes vm_object_lock(object); 2961541Srgrimes vm_page_lock_queues(); 2971541Srgrimes vm_page_free(m); 2981541Srgrimes vm_page_insert(page, object, offset); 2991541Srgrimes vm_page_unlock_queues(); 3001541Srgrimes PAGE_WAKEUP(m); 3011541Srgrimes if (offset + PAGE_SIZE > object->size) 3021541Srgrimes object->size = offset + PAGE_SIZE; /* XXX anal */ 3031541Srgrimes vm_object_unlock(object); 3041541Srgrimes 3051541Srgrimes return(VM_PAGER_OK); 3061541Srgrimes} 3071541Srgrimes 3081541Srgrimesstatic int 3091541Srgrimesdev_pager_putpage(pager, mlist, npages, sync) 3101541Srgrimes vm_pager_t pager; 3111541Srgrimes vm_page_t *mlist; 3121541Srgrimes int npages; 3131541Srgrimes boolean_t sync; 3141541Srgrimes{ 3151541Srgrimes#ifdef DEBUG 3161541Srgrimes if (dpagerdebug & DDB_FOLLOW) 3171541Srgrimes printf("dev_pager_putpage(%x, %x, %x, %x)\n", 3181541Srgrimes pager, mlist, npages, sync); 3191541Srgrimes#endif 3201541Srgrimes if (pager == NULL) 3211541Srgrimes return; 3221541Srgrimes panic("dev_pager_putpage called"); 3231541Srgrimes} 3241541Srgrimes 3251541Srgrimesstatic boolean_t 3261541Srgrimesdev_pager_haspage(pager, offset) 3271541Srgrimes vm_pager_t pager; 3281541Srgrimes vm_offset_t offset; 3291541Srgrimes{ 3301541Srgrimes#ifdef DEBUG 3311541Srgrimes if (dpagerdebug & DDB_FOLLOW) 3321541Srgrimes printf("dev_pager_haspage(%x, %x)\n", pager, offset); 3331541Srgrimes#endif 3341541Srgrimes return(TRUE); 3351541Srgrimes} 3361541Srgrimes 3371541Srgrimesstatic vm_page_t 3381541Srgrimesdev_pager_getfake(paddr) 3391541Srgrimes vm_offset_t paddr; 3401541Srgrimes{ 3411541Srgrimes vm_page_t m; 3421541Srgrimes int i; 3431541Srgrimes 3441541Srgrimes if (dev_pager_fakelist.tqh_first == NULL) { 3451541Srgrimes m = (vm_page_t)malloc(PAGE_SIZE, M_VMPGDATA, M_WAITOK); 3461541Srgrimes for (i = PAGE_SIZE / sizeof(*m); i > 0; i--) { 3471541Srgrimes TAILQ_INSERT_TAIL(&dev_pager_fakelist, m, pageq); 3481541Srgrimes m++; 3491541Srgrimes } 3501541Srgrimes } 3511541Srgrimes m = dev_pager_fakelist.tqh_first; 3521541Srgrimes TAILQ_REMOVE(&dev_pager_fakelist, m, pageq); 3531541Srgrimes m->flags = PG_BUSY | PG_CLEAN | PG_FAKE | PG_FICTITIOUS; 3541541Srgrimes m->phys_addr = paddr; 3551541Srgrimes m->wire_count = 1; 3561541Srgrimes return(m); 3571541Srgrimes} 3581541Srgrimes 3591541Srgrimesstatic void 3601541Srgrimesdev_pager_putfake(m) 3611541Srgrimes vm_page_t m; 3621541Srgrimes{ 3631541Srgrimes#ifdef DIAGNOSTIC 3641541Srgrimes if (!(m->flags & PG_FICTITIOUS)) 3651541Srgrimes panic("dev_pager_putfake: bad page"); 3661541Srgrimes#endif 3671541Srgrimes TAILQ_INSERT_TAIL(&dev_pager_fakelist, m, pageq); 3681541Srgrimes} 369