Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/mem.c
Version:
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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: releng/11.2/sys/i386/i386/mem.c 331722 2018-03-29 02:50:57Z eadler $"); 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 */ 73 MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors"); 74 75 static struct sx memsxlock; 76 SX_SYSINIT(memsxlockinit, &memsxlock, "/dev/mem lock"); 77 78 /* ARGSUSED */ 79 int 80 memrw(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 if (uio->uio_offset > cpu_getmaxphyaddr()) { 112 error = EFAULT; 113 break; 114 } 115 pa = trunc_page(uio->uio_offset); 116 } else { 117 /* 118 * Extract the physical page since the mapping may 119 * change at any time. This avoids panics on page 120 * fault in this case but will cause reading/writing 121 * to the wrong page. 122 * Hopefully an application will notice the wrong 123 * data on read access and refrain from writing. 124 * This should be replaced by a special uiomove 125 * type function that just returns an error if there 126 * is a page fault on a kernel page. 127 */ 128 addr = trunc_page(uio->uio_offset); 129 pa = pmap_extract(kernel_pmap, addr); 130 if (pa == 0) 131 return EFAULT; 132 133 } 134 135 /* 136 * XXX UPS This should just use sf_buf_alloc. 137 * Unfortunately sf_buf_alloc needs a vm_page 138 * and we may want to look at memory not covered 139 * by the page array. 140 */ 141 142 sx_xlock(&memsxlock); 143 pmap_kenter((vm_offset_t)ptvmmap, pa); 144 pmap_invalidate_page(kernel_pmap,(vm_offset_t)ptvmmap); 145 146 o = (int)uio->uio_offset & PAGE_MASK; 147 c = PAGE_SIZE - o; 148 c = min(c, (u_int)iov->iov_len); 149 error = uiomove((caddr_t)&ptvmmap[o], (int)c, uio); 150 pmap_qremove((vm_offset_t)ptvmmap, 1); 151 sx_xunlock(&memsxlock); 152 153 } 154 155 return (error); 156 } 157 158 /* 159 * allow user processes to MMAP some memory sections 160 * instead of going through read/write 161 */ 162 /* ARGSUSED */ 163 int 164 memmmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, 165 int prot __unused, vm_memattr_t *memattr __unused) 166 { 167 if (dev2unit(dev) == CDEV_MINOR_MEM) { 168 if (offset > cpu_getmaxphyaddr()) 169 return (-1); 170 *paddr = offset; 171 return (0); 172 } 173 return (-1); 174 } 175 176 /* 177 * Operations for changing memory attributes. 178 * 179 * This is basically just an ioctl shim for mem_range_attr_get 180 * and mem_range_attr_set. 181 */ 182 /* ARGSUSED */ 183 int 184 memioctl(struct cdev *dev __unused, u_long cmd, caddr_t data, int flags, 185 struct thread *td) 186 { 187 int nd, error = 0; 188 struct mem_range_op *mo = (struct mem_range_op *)data; 189 struct mem_range_desc *md; 190 191 /* is this for us? */ 192 if ((cmd != MEMRANGE_GET) && 193 (cmd != MEMRANGE_SET)) 194 return (ENOTTY); 195 196 /* any chance we can handle this? */ 197 if (mem_range_softc.mr_op == NULL) 198 return (EOPNOTSUPP); 199 200 /* do we have any descriptors? */ 201 if (mem_range_softc.mr_ndesc == 0) 202 return (ENXIO); 203 204 switch (cmd) { 205 case MEMRANGE_GET: 206 nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc); 207 if (nd > 0) { 208 md = (struct mem_range_desc *) 209 malloc(nd * sizeof(struct mem_range_desc), 210 M_MEMDESC, M_WAITOK); 211 error = mem_range_attr_get(md, &nd); 212 if (!error) 213 error = copyout(md, mo->mo_desc, 214 nd * sizeof(struct mem_range_desc)); 215 free(md, M_MEMDESC); 216 } 217 else 218 nd = mem_range_softc.mr_ndesc; 219 mo->mo_arg[0] = nd; 220 break; 221 222 case MEMRANGE_SET: 223 md = (struct mem_range_desc *)malloc(sizeof(struct mem_range_desc), 224 M_MEMDESC, M_WAITOK); 225 error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc)); 226 /* clamp description string */ 227 md->mr_owner[sizeof(md->mr_owner) - 1] = 0; 228 if (error == 0) 229 error = mem_range_attr_set(md, &mo->mo_arg[0]); 230 free(md, M_MEMDESC); 231 break; 232 } 233 return (error); 234 }
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