The Design and Implementation of the FreeBSD Operating System, Second Edition
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

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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  * 3. All advertising materials mentioning features or use of this software
   20  *    must display the following acknowledgement:
   21  *      This product includes software developed by the University of
   22  *      California, Berkeley and its contributors.
   23  * 4. Neither the name of the University nor the names of its contributors
   24  *    may be used to endorse or promote products derived from this software
   25  *    without specific prior written permission.
   26  *
   27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   37  * SUCH DAMAGE.
   38  *
   39  *      from: Utah $Hdr: mem.c 1.13 89/10/08$
   40  *      from: @(#)mem.c 7.2 (Berkeley) 5/9/91
   41  */
   42 
   43 #include <sys/cdefs.h>
   44 __FBSDID("$FreeBSD: releng/5.2/sys/i386/i386/mem.c 115683 2003-06-02 06:43:15Z obrien $");
   45 
   46 /*
   47  * Memory special file
   48  */
   49 
   50 #include <sys/param.h>
   51 #include <sys/conf.h>
   52 #include <sys/fcntl.h>
   53 #include <sys/ioccom.h>
   54 #include <sys/kernel.h>
   55 #include <sys/lock.h>
   56 #include <sys/malloc.h>
   57 #include <sys/memrange.h>
   58 #include <sys/mutex.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/db_machdep.h>
   65 #include <machine/frame.h>
   66 #include <machine/psl.h>
   67 #include <machine/specialreg.h>
   68 
   69 #include <vm/vm.h>
   70 #include <vm/pmap.h>
   71 #include <vm/vm_extern.h>
   72 
   73 static dev_t memdev, kmemdev, iodev;
   74 
   75 static  d_open_t        mmopen;
   76 static  d_close_t       mmclose;
   77 static  d_read_t        mmrw;
   78 static  d_ioctl_t       mmioctl;
   79 static  d_mmap_t        memmmap;
   80 
   81 #define CDEV_MAJOR 2
   82 static struct cdevsw mem_cdevsw = {
   83         .d_open =       mmopen,
   84         .d_close =      mmclose,
   85         .d_read =       mmrw,
   86         .d_write =      mmrw,
   87         .d_ioctl =      mmioctl,
   88         .d_mmap =       memmmap,
   89         .d_name =       "mem",
   90         .d_maj =        CDEV_MAJOR,
   91         .d_flags =      D_MEM,
   92 };
   93 
   94 MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors");
   95 
   96 struct mem_range_softc mem_range_softc;
   97 
   98 static int
   99 mmclose(dev_t dev, int flags, int fmt, struct thread *td)
  100 {
  101         switch (minor(dev)) {
  102         case 14:
  103                 td->td_frame->tf_eflags &= ~PSL_IOPL;
  104         }
  105         return (0);
  106 }
  107 
  108 static int
  109 mmopen(dev_t dev, int flags, int fmt, struct thread *td)
  110 {
  111         int error;
  112 
  113         switch (minor(dev)) {
  114         case 0:
  115         case 1:
  116                 if (flags & FWRITE) {
  117                         error = securelevel_gt(td->td_ucred, 0);
  118                         if (error != 0)
  119                                 return (error);
  120                 }
  121                 break;
  122         case 14:
  123                 error = suser(td);
  124                 if (error != 0)
  125                         return (error);
  126                 error = securelevel_gt(td->td_ucred, 0);
  127                 if (error != 0)
  128                         return (error);
  129                 td->td_frame->tf_eflags |= PSL_IOPL;
  130                 break;
  131         }
  132         return (0);
  133 }
  134 
  135 /*ARGSUSED*/
  136 static int
  137 mmrw(dev_t dev, struct uio *uio, int flags)
  138 {
  139         int o;
  140         u_int c = 0, v;
  141         struct iovec *iov;
  142         int error = 0;
  143         vm_offset_t addr, eaddr;
  144 
  145         GIANT_REQUIRED;
  146 
  147         while (uio->uio_resid > 0 && error == 0) {
  148                 iov = uio->uio_iov;
  149                 if (iov->iov_len == 0) {
  150                         uio->uio_iov++;
  151                         uio->uio_iovcnt--;
  152                         if (uio->uio_iovcnt < 0)
  153                                 panic("mmrw");
  154                         continue;
  155                 }
  156                 switch (minor(dev)) {
  157 
  158 /* minor device 0 is physical memory */
  159                 case 0:
  160                         v = uio->uio_offset;
  161                         v &= ~PAGE_MASK;
  162                         pmap_kenter((vm_offset_t)ptvmmap, v);
  163                         o = (int)uio->uio_offset & PAGE_MASK;
  164                         c = (u_int)(PAGE_SIZE - ((int)iov->iov_base & PAGE_MASK));
  165                         c = min(c, (u_int)(PAGE_SIZE - o));
  166                         c = min(c, (u_int)iov->iov_len);
  167                         error = uiomove((caddr_t)&ptvmmap[o], (int)c, uio);
  168                         pmap_qremove((vm_offset_t)ptvmmap, 1);
  169                         continue;
  170 
  171 /* minor device 1 is kernel memory */
  172                 case 1:
  173                         c = iov->iov_len;
  174 
  175                         /*
  176                          * Make sure that all of the pages are currently resident so
  177                          * that we don't create any zero-fill pages.
  178                          */
  179                         addr = trunc_page(uio->uio_offset);
  180                         eaddr = round_page(uio->uio_offset + c);
  181 
  182                         if (addr < (vm_offset_t)VADDR(PTDPTDI, 0))
  183                                 return (EFAULT);
  184                         for (; addr < eaddr; addr += PAGE_SIZE) 
  185                                 if (pmap_extract(kernel_pmap, addr) == 0)
  186                                         return (EFAULT);
  187 
  188                         if (!kernacc((caddr_t)(int)uio->uio_offset, c,
  189                             uio->uio_rw == UIO_READ ? 
  190                             VM_PROT_READ : VM_PROT_WRITE))
  191                                 return (EFAULT);
  192                         error = uiomove((caddr_t)(int)uio->uio_offset, (int)c, uio);
  193                         continue;
  194 
  195                 default:
  196                         return (ENODEV);
  197                 }
  198 
  199                 if (error)
  200                         break;
  201                 iov->iov_base = (char *)iov->iov_base + c;
  202                 iov->iov_len -= c;
  203                 uio->uio_offset += c;
  204                 uio->uio_resid -= c;
  205         }
  206         return (error);
  207 }
  208 
  209 /*******************************************************\
  210 * allow user processes to MMAP some memory sections     *
  211 * instead of going through read/write                   *
  212 \*******************************************************/
  213 static int
  214 memmmap(dev_t dev, vm_offset_t offset, vm_paddr_t *paddr, int prot)
  215 {
  216         switch (minor(dev))
  217         {
  218 
  219         /* minor device 0 is physical memory */
  220         case 0:
  221                 *paddr = offset;
  222                 break;
  223 
  224         /* minor device 1 is kernel memory */
  225         case 1:
  226                 *paddr = vtophys(offset);
  227                 break;
  228 
  229         default:
  230                 return (-1);
  231         }
  232         return (0);
  233 }
  234 
  235 /*
  236  * Operations for changing memory attributes.
  237  *
  238  * This is basically just an ioctl shim for mem_range_attr_get
  239  * and mem_range_attr_set.
  240  */
  241 static int 
  242 mmioctl(dev_t dev, u_long cmd, caddr_t data, int flags, struct thread *td)
  243 {
  244         int nd, error = 0;
  245         struct mem_range_op *mo = (struct mem_range_op *)data;
  246         struct mem_range_desc *md;
  247         
  248         /* is this for us? */
  249         if ((cmd != MEMRANGE_GET) &&
  250             (cmd != MEMRANGE_SET))
  251                 return (ENOTTY);
  252 
  253         /* any chance we can handle this? */
  254         if (mem_range_softc.mr_op == NULL)
  255                 return (EOPNOTSUPP);
  256 
  257         /* do we have any descriptors? */
  258         if (mem_range_softc.mr_ndesc == 0)
  259                 return (ENXIO);
  260 
  261         switch (cmd) {
  262         case MEMRANGE_GET:
  263                 nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc);
  264                 if (nd > 0) {
  265                         md = (struct mem_range_desc *)
  266                                 malloc(nd * sizeof(struct mem_range_desc),
  267                                        M_MEMDESC, M_WAITOK);
  268                         error = mem_range_attr_get(md, &nd);
  269                         if (!error)
  270                                 error = copyout(md, mo->mo_desc, 
  271                                         nd * sizeof(struct mem_range_desc));
  272                         free(md, M_MEMDESC);
  273                 }
  274                 else
  275                         nd = mem_range_softc.mr_ndesc;
  276                 mo->mo_arg[0] = nd;
  277                 break;
  278                 
  279         case MEMRANGE_SET:
  280                 md = (struct mem_range_desc *)malloc(sizeof(struct mem_range_desc),
  281                                                     M_MEMDESC, M_WAITOK);
  282                 error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc));
  283                 /* clamp description string */
  284                 md->mr_owner[sizeof(md->mr_owner) - 1] = 0;
  285                 if (error == 0)
  286                         error = mem_range_attr_set(md, &mo->mo_arg[0]);
  287                 free(md, M_MEMDESC);
  288                 break;
  289         }
  290         return (error);
  291 }
  292 
  293 /*
  294  * Implementation-neutral, kernel-callable functions for manipulating
  295  * memory range attributes.
  296  */
  297 int
  298 mem_range_attr_get(struct mem_range_desc *mrd, int *arg)
  299 {
  300         /* can we handle this? */
  301         if (mem_range_softc.mr_op == NULL)
  302                 return (EOPNOTSUPP);
  303 
  304         if (*arg == 0)
  305                 *arg = mem_range_softc.mr_ndesc;
  306         else
  307                 bcopy(mem_range_softc.mr_desc, mrd,
  308                         (*arg) * sizeof(struct mem_range_desc));
  309         return (0);
  310 }
  311 
  312 int
  313 mem_range_attr_set(struct mem_range_desc *mrd, int *arg)
  314 {
  315         /* can we handle this? */
  316         if (mem_range_softc.mr_op == NULL)
  317                 return (EOPNOTSUPP);
  318 
  319         return (mem_range_softc.mr_op->set(&mem_range_softc, mrd, arg));
  320 }
  321 
  322 #ifdef SMP
  323 void
  324 mem_range_AP_init(void)
  325 {
  326         if (mem_range_softc.mr_op && mem_range_softc.mr_op->initAP)
  327                 (mem_range_softc.mr_op->initAP(&mem_range_softc));
  328 }
  329 #endif
  330 
  331 static int
  332 mem_modevent(module_t mod, int type, void *data)
  333 {
  334         switch(type) {
  335         case MOD_LOAD:
  336                 if (bootverbose)
  337                         printf("mem: <memory & I/O>\n");
  338                 /* Initialise memory range handling */
  339                 if (mem_range_softc.mr_op != NULL)
  340                         mem_range_softc.mr_op->init(&mem_range_softc);
  341 
  342                 memdev = make_dev(&mem_cdevsw, 0, UID_ROOT, GID_KMEM,
  343                         0640, "mem");
  344                 kmemdev = make_dev(&mem_cdevsw, 1, UID_ROOT, GID_KMEM,
  345                         0640, "kmem");
  346                 iodev = make_dev(&mem_cdevsw, 14, UID_ROOT, GID_WHEEL,
  347                         0600, "io");
  348                 return (0);
  349 
  350         case MOD_UNLOAD:
  351                 destroy_dev(memdev);
  352                 destroy_dev(kmemdev);
  353                 destroy_dev(iodev);
  354                 return (0);
  355 
  356         case MOD_SHUTDOWN:
  357                 return (0);
  358 
  359         default:
  360                 return (EOPNOTSUPP);
  361         }
  362 }
  363 
  364 DEV_MODULE(mem, mem_modevent, NULL);

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