sys/i386/i386/mem.c

   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("$FreeBSD$");
  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                         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 */
 160 int
 161 memmmap(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 */
 179 int
 180 memioctl(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 }