mem.c revision 330897
1/*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1988 University of Utah. 5 * Copyright (c) 1982, 1986, 1990 The Regents of the University of California. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department, and code derived from software contributed to 11 * Berkeley by William Jolitz. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: Utah $Hdr: mem.c 1.13 89/10/08$ 38 * from: @(#)mem.c 7.2 (Berkeley) 5/9/91 39 */ 40 41#include <sys/cdefs.h> 42__FBSDID("$FreeBSD: stable/11/sys/i386/i386/mem.c 330897 2018-03-14 03:19:51Z eadler $"); 43 44/* 45 * Memory special file 46 */ 47 48#include <sys/param.h> 49#include <sys/conf.h> 50#include <sys/fcntl.h> 51#include <sys/ioccom.h> 52#include <sys/kernel.h> 53#include <sys/lock.h> 54#include <sys/malloc.h> 55#include <sys/memrange.h> 56#include <sys/module.h> 57#include <sys/mutex.h> 58#include <sys/sx.h> 59#include <sys/proc.h> 60#include <sys/signalvar.h> 61#include <sys/systm.h> 62#include <sys/uio.h> 63 64#include <machine/specialreg.h> 65 66#include <vm/vm.h> 67#include <vm/pmap.h> 68#include <vm/vm_extern.h> 69 70#include <machine/memdev.h> 71 72/* 73 * Used in /dev/mem drivers and elsewhere 74 */ 75MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors"); 76 77static struct sx memsxlock; 78SX_SYSINIT(memsxlockinit, &memsxlock, "/dev/mem lock"); 79 80/* ARGSUSED */ 81int 82memrw(struct cdev *dev, struct uio *uio, int flags) 83{ 84 int o; 85 u_int c = 0; 86 vm_paddr_t pa; 87 struct iovec *iov; 88 int error = 0; 89 vm_offset_t addr; 90 91 if (dev2unit(dev) != CDEV_MINOR_MEM && dev2unit(dev) != CDEV_MINOR_KMEM) 92 return EIO; 93 94 if (dev2unit(dev) == CDEV_MINOR_KMEM && uio->uio_resid > 0) { 95 if (uio->uio_offset < (vm_offset_t)VADDR(PTDPTDI, 0)) 96 return (EFAULT); 97 98 if (!kernacc((caddr_t)(int)uio->uio_offset, uio->uio_resid, 99 uio->uio_rw == UIO_READ ? VM_PROT_READ : VM_PROT_WRITE)) 100 return (EFAULT); 101 } 102 103 while (uio->uio_resid > 0 && error == 0) { 104 iov = uio->uio_iov; 105 if (iov->iov_len == 0) { 106 uio->uio_iov++; 107 uio->uio_iovcnt--; 108 if (uio->uio_iovcnt < 0) 109 panic("memrw"); 110 continue; 111 } 112 if (dev2unit(dev) == CDEV_MINOR_MEM) { 113 if (uio->uio_offset > cpu_getmaxphyaddr()) { 114 error = EFAULT; 115 break; 116 } 117 pa = trunc_page(uio->uio_offset); 118 } else { 119 /* 120 * Extract the physical page since the mapping may 121 * change at any time. This avoids panics on page 122 * fault in this case but will cause reading/writing 123 * to the wrong page. 124 * Hopefully an application will notice the wrong 125 * data on read access and refrain from writing. 126 * This should be replaced by a special uiomove 127 * type function that just returns an error if there 128 * is a page fault on a kernel page. 129 */ 130 addr = trunc_page(uio->uio_offset); 131 pa = pmap_extract(kernel_pmap, addr); 132 if (pa == 0) 133 return EFAULT; 134 135 } 136 137 /* 138 * XXX UPS This should just use sf_buf_alloc. 139 * Unfortunately sf_buf_alloc needs a vm_page 140 * and we may want to look at memory not covered 141 * by the page array. 142 */ 143 144 sx_xlock(&memsxlock); 145 pmap_kenter((vm_offset_t)ptvmmap, pa); 146 pmap_invalidate_page(kernel_pmap,(vm_offset_t)ptvmmap); 147 148 o = (int)uio->uio_offset & PAGE_MASK; 149 c = PAGE_SIZE - o; 150 c = min(c, (u_int)iov->iov_len); 151 error = uiomove((caddr_t)&ptvmmap[o], (int)c, uio); 152 pmap_qremove((vm_offset_t)ptvmmap, 1); 153 sx_xunlock(&memsxlock); 154 155 } 156 157 return (error); 158} 159 160/* 161 * allow user processes to MMAP some memory sections 162 * instead of going through read/write 163 */ 164/* ARGSUSED */ 165int 166memmmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, 167 int prot __unused, vm_memattr_t *memattr __unused) 168{ 169 if (dev2unit(dev) == CDEV_MINOR_MEM) { 170 if (offset > cpu_getmaxphyaddr()) 171 return (-1); 172 *paddr = offset; 173 return (0); 174 } 175 return (-1); 176} 177 178/* 179 * Operations for changing memory attributes. 180 * 181 * This is basically just an ioctl shim for mem_range_attr_get 182 * and mem_range_attr_set. 183 */ 184/* ARGSUSED */ 185int 186memioctl(struct cdev *dev __unused, u_long cmd, caddr_t data, int flags, 187 struct thread *td) 188{ 189 int nd, error = 0; 190 struct mem_range_op *mo = (struct mem_range_op *)data; 191 struct mem_range_desc *md; 192 193 /* is this for us? */ 194 if ((cmd != MEMRANGE_GET) && 195 (cmd != MEMRANGE_SET)) 196 return (ENOTTY); 197 198 /* any chance we can handle this? */ 199 if (mem_range_softc.mr_op == NULL) 200 return (EOPNOTSUPP); 201 202 /* do we have any descriptors? */ 203 if (mem_range_softc.mr_ndesc == 0) 204 return (ENXIO); 205 206 switch (cmd) { 207 case MEMRANGE_GET: 208 nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc); 209 if (nd > 0) { 210 md = (struct mem_range_desc *) 211 malloc(nd * sizeof(struct mem_range_desc), 212 M_MEMDESC, M_WAITOK); 213 error = mem_range_attr_get(md, &nd); 214 if (!error) 215 error = copyout(md, mo->mo_desc, 216 nd * sizeof(struct mem_range_desc)); 217 free(md, M_MEMDESC); 218 } 219 else 220 nd = mem_range_softc.mr_ndesc; 221 mo->mo_arg[0] = nd; 222 break; 223 224 case MEMRANGE_SET: 225 md = (struct mem_range_desc *)malloc(sizeof(struct mem_range_desc), 226 M_MEMDESC, M_WAITOK); 227 error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc)); 228 /* clamp description string */ 229 md->mr_owner[sizeof(md->mr_owner) - 1] = 0; 230 if (error == 0) 231 error = mem_range_attr_set(md, &mo->mo_arg[0]); 232 free(md, M_MEMDESC); 233 break; 234 } 235 return (error); 236} 237