mem.c revision 278746
1/*- 2 * Copyright (c) 1988 University of Utah. 3 * Copyright (c) 1982, 1986, 1990 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the Systems Programming Group of the University of Utah Computer 8 * Science Department, and code derived from software contributed to 9 * Berkeley by William Jolitz. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * from: Utah $Hdr: mem.c 1.13 89/10/08$ 36 * from: @(#)mem.c 7.2 (Berkeley) 5/9/91 37 */ 38 39#include <sys/cdefs.h> 40__FBSDID("$FreeBSD: stable/10/sys/i386/i386/mem.c 278746 2015-02-14 08:44:12Z kib $"); 41 42/* 43 * Memory special file 44 */ 45 46#include <sys/param.h> 47#include <sys/conf.h> 48#include <sys/fcntl.h> 49#include <sys/ioccom.h> 50#include <sys/kernel.h> 51#include <sys/lock.h> 52#include <sys/malloc.h> 53#include <sys/memrange.h> 54#include <sys/module.h> 55#include <sys/mutex.h> 56#include <sys/sx.h> 57#include <sys/proc.h> 58#include <sys/signalvar.h> 59#include <sys/systm.h> 60#include <sys/uio.h> 61 62#include <machine/specialreg.h> 63 64#include <vm/vm.h> 65#include <vm/pmap.h> 66#include <vm/vm_extern.h> 67 68#include <machine/memdev.h> 69 70/* 71 * Used in /dev/mem drivers and elsewhere 72 */ 73MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors"); 74 75static struct sx memsxlock; 76SX_SYSINIT(memsxlockinit, &memsxlock, "/dev/mem lock"); 77 78/* ARGSUSED */ 79int 80memrw(struct cdev *dev, struct uio *uio, int flags) 81{ 82 int o; 83 u_int c = 0; 84 vm_paddr_t pa; 85 struct iovec *iov; 86 int error = 0; 87 vm_offset_t addr; 88 89 if (dev2unit(dev) != CDEV_MINOR_MEM && dev2unit(dev) != CDEV_MINOR_KMEM) 90 return EIO; 91 92 if (dev2unit(dev) == CDEV_MINOR_KMEM && uio->uio_resid > 0) { 93 if (uio->uio_offset < (vm_offset_t)VADDR(PTDPTDI, 0)) 94 return (EFAULT); 95 96 if (!kernacc((caddr_t)(int)uio->uio_offset, uio->uio_resid, 97 uio->uio_rw == UIO_READ ? VM_PROT_READ : VM_PROT_WRITE)) 98 return (EFAULT); 99 } 100 101 while (uio->uio_resid > 0 && error == 0) { 102 iov = uio->uio_iov; 103 if (iov->iov_len == 0) { 104 uio->uio_iov++; 105 uio->uio_iovcnt--; 106 if (uio->uio_iovcnt < 0) 107 panic("memrw"); 108 continue; 109 } 110 if (dev2unit(dev) == CDEV_MINOR_MEM) { 111 pa = uio->uio_offset; 112 pa &= ~PAGE_MASK; 113 } else { 114 /* 115 * Extract the physical page since the mapping may 116 * change at any time. This avoids panics on page 117 * fault in this case but will cause reading/writing 118 * to the wrong page. 119 * Hopefully an application will notice the wrong 120 * data on read access and refrain from writing. 121 * This should be replaced by a special uiomove 122 * type function that just returns an error if there 123 * is a page fault on a kernel page. 124 */ 125 addr = trunc_page(uio->uio_offset); 126 pa = pmap_extract(kernel_pmap, addr); 127 if (pa == 0) 128 return EFAULT; 129 130 } 131 132 /* 133 * XXX UPS This should just use sf_buf_alloc. 134 * Unfortunately sf_buf_alloc needs a vm_page 135 * and we may want to look at memory not covered 136 * by the page array. 137 */ 138 139 sx_xlock(&memsxlock); 140 pmap_kenter((vm_offset_t)ptvmmap, pa); 141 pmap_invalidate_page(kernel_pmap,(vm_offset_t)ptvmmap); 142 143 o = (int)uio->uio_offset & PAGE_MASK; 144 c = PAGE_SIZE - o; 145 c = min(c, (u_int)iov->iov_len); 146 error = uiomove((caddr_t)&ptvmmap[o], (int)c, uio); 147 pmap_qremove((vm_offset_t)ptvmmap, 1); 148 sx_xunlock(&memsxlock); 149 150 } 151 152 return (error); 153} 154 155/* 156 * allow user processes to MMAP some memory sections 157 * instead of going through read/write 158 */ 159/* ARGSUSED */ 160int 161memmmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, 162 int prot __unused, vm_memattr_t *memattr __unused) 163{ 164 if (dev2unit(dev) == CDEV_MINOR_MEM) 165 *paddr = offset; 166 else if (dev2unit(dev) == CDEV_MINOR_KMEM) 167 *paddr = vtophys(offset); 168 /* else panic! */ 169 return (0); 170} 171 172/* 173 * Operations for changing memory attributes. 174 * 175 * This is basically just an ioctl shim for mem_range_attr_get 176 * and mem_range_attr_set. 177 */ 178/* ARGSUSED */ 179int 180memioctl(struct cdev *dev __unused, u_long cmd, caddr_t data, int flags, 181 struct thread *td) 182{ 183 int nd, error = 0; 184 struct mem_range_op *mo = (struct mem_range_op *)data; 185 struct mem_range_desc *md; 186 187 /* is this for us? */ 188 if ((cmd != MEMRANGE_GET) && 189 (cmd != MEMRANGE_SET)) 190 return (ENOTTY); 191 192 /* any chance we can handle this? */ 193 if (mem_range_softc.mr_op == NULL) 194 return (EOPNOTSUPP); 195 196 /* do we have any descriptors? */ 197 if (mem_range_softc.mr_ndesc == 0) 198 return (ENXIO); 199 200 switch (cmd) { 201 case MEMRANGE_GET: 202 nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc); 203 if (nd > 0) { 204 md = (struct mem_range_desc *) 205 malloc(nd * sizeof(struct mem_range_desc), 206 M_MEMDESC, M_WAITOK); 207 error = mem_range_attr_get(md, &nd); 208 if (!error) 209 error = copyout(md, mo->mo_desc, 210 nd * sizeof(struct mem_range_desc)); 211 free(md, M_MEMDESC); 212 } 213 else 214 nd = mem_range_softc.mr_ndesc; 215 mo->mo_arg[0] = nd; 216 break; 217 218 case MEMRANGE_SET: 219 md = (struct mem_range_desc *)malloc(sizeof(struct mem_range_desc), 220 M_MEMDESC, M_WAITOK); 221 error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc)); 222 /* clamp description string */ 223 md->mr_owner[sizeof(md->mr_owner) - 1] = 0; 224 if (error == 0) 225 error = mem_range_attr_set(md, &mo->mo_arg[0]); 226 free(md, M_MEMDESC); 227 break; 228 } 229 return (error); 230} 231