vm_unix.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 1988 University of Utah.
    5  * Copyright (c) 1991, 1993
    6  *      The Regents of the University of California.  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.
   11  *
   12  * Redistribution and use in source and binary forms, with or without
   13  * modification, are permitted provided that the following conditions
   14  * are met:
   15  * 1. Redistributions of source code must retain the above copyright
   16  *    notice, this list of conditions and the following disclaimer.
   17  * 2. Redistributions in binary form must reproduce the above copyright
   18  *    notice, this list of conditions and the following disclaimer in the
   19  *    documentation and/or other materials provided with the distribution.
   20  * 3. Neither the name of the University nor the names of its contributors
   21  *    may be used to endorse or promote products derived from this software
   22  *    without specific prior written permission.
   23  *
   24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   34  * SUCH DAMAGE.
   35  *
   36  * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
   37  *
   38  *      @(#)vm_unix.c   8.1 (Berkeley) 6/11/93
   39  */
   40 
   41 /*
   42  * Traditional sbrk/grow interface to VM
   43  */
   44 
   45 #include <sys/cdefs.h>
   46 __FBSDID("$FreeBSD: releng/12.0/sys/vm/vm_unix.c 336650 2018-07-23 19:49:54Z lwhsu $");
   47 
   48 #include <sys/param.h>
   49 #include <sys/lock.h>
   50 #include <sys/mutex.h>
   51 #include <sys/proc.h>
   52 #include <sys/racct.h>
   53 #include <sys/resourcevar.h>
   54 #include <sys/syscallsubr.h>
   55 #include <sys/sysent.h>
   56 #include <sys/sysproto.h>
   57 #include <sys/systm.h>
   58 
   59 #include <vm/vm.h>
   60 #include <vm/vm_param.h>
   61 #include <vm/pmap.h>
   62 #include <vm/vm_map.h>
   63 
   64 #ifndef _SYS_SYSPROTO_H_
   65 struct break_args {
   66         char *nsize;
   67 };
   68 #endif
   69 int
   70 sys_break(struct thread *td, struct break_args *uap)
   71 {
   72 #if !defined(__aarch64__) && !defined(__riscv)
   73         uintptr_t addr;
   74         int error;
   75 
   76         addr = (uintptr_t)uap->nsize;
   77         error = kern_break(td, &addr);
   78         if (error == 0)
   79                 td->td_retval[0] = addr;
   80         return (error);
   81 #else /* defined(__aarch64__) || defined(__riscv) */
   82         return (ENOSYS);
   83 #endif /* defined(__aarch64__) || defined(__riscv) */
   84 }
   85 
   86 int
   87 kern_break(struct thread *td, uintptr_t *addr)
   88 {
   89         struct vmspace *vm = td->td_proc->p_vmspace;
   90         vm_map_t map = &vm->vm_map;
   91         vm_offset_t new, old, base;
   92         rlim_t datalim, lmemlim, vmemlim;
   93         int prot, rv;
   94         int error = 0;
   95         boolean_t do_map_wirefuture;
   96 
   97         datalim = lim_cur(td, RLIMIT_DATA);
   98         lmemlim = lim_cur(td, RLIMIT_MEMLOCK);
   99         vmemlim = lim_cur(td, RLIMIT_VMEM);
  100 
  101         do_map_wirefuture = FALSE;
  102         new = round_page(*addr);
  103         vm_map_lock(map);
  104 
  105         base = round_page((vm_offset_t) vm->vm_daddr);
  106         old = base + ctob(vm->vm_dsize);
  107         if (new > base) {
  108                 /*
  109                  * Check the resource limit, but allow a process to reduce
  110                  * its usage, even if it remains over the limit.
  111                  */
  112                 if (new - base > datalim && new > old) {
  113                         error = ENOMEM;
  114                         goto done;
  115                 }
  116                 if (new > vm_map_max(map)) {
  117                         error = ENOMEM;
  118                         goto done;
  119                 }
  120         } else if (new < base) {
  121                 /*
  122                  * Simply return the current break address without
  123                  * modifying any state.  This is an ad-hoc interface
  124                  * used by libc to determine the initial break address,
  125                  * avoiding a dependency on magic features in the system
  126                  * linker.
  127                  */
  128                 new = old;
  129                 goto done;
  130         }
  131 
  132         if (new > old) {
  133                 if (!old_mlock && map->flags & MAP_WIREFUTURE) {
  134                         if (ptoa(pmap_wired_count(map->pmap)) +
  135                             (new - old) > lmemlim) {
  136                                 error = ENOMEM;
  137                                 goto done;
  138                         }
  139                 }
  140                 if (map->size + (new - old) > vmemlim) {
  141                         error = ENOMEM;
  142                         goto done;
  143                 }
  144 #ifdef RACCT
  145                 if (racct_enable) {
  146                         PROC_LOCK(td->td_proc);
  147                         error = racct_set(td->td_proc, RACCT_DATA, new - base);
  148                         if (error != 0) {
  149                                 PROC_UNLOCK(td->td_proc);
  150                                 error = ENOMEM;
  151                                 goto done;
  152                         }
  153                         error = racct_set(td->td_proc, RACCT_VMEM,
  154                             map->size + (new - old));
  155                         if (error != 0) {
  156                                 racct_set_force(td->td_proc, RACCT_DATA,
  157                                     old - base);
  158                                 PROC_UNLOCK(td->td_proc);
  159                                 error = ENOMEM;
  160                                 goto done;
  161                         }
  162                         if (!old_mlock && map->flags & MAP_WIREFUTURE) {
  163                                 error = racct_set(td->td_proc, RACCT_MEMLOCK,
  164                                     ptoa(pmap_wired_count(map->pmap)) +
  165                                     (new - old));
  166                                 if (error != 0) {
  167                                         racct_set_force(td->td_proc, RACCT_DATA,
  168                                             old - base);
  169                                         racct_set_force(td->td_proc, RACCT_VMEM,
  170                                             map->size);
  171                                         PROC_UNLOCK(td->td_proc);
  172                                         error = ENOMEM;
  173                                         goto done;
  174                                 }
  175                         }
  176                         PROC_UNLOCK(td->td_proc);
  177                 }
  178 #endif
  179                 prot = VM_PROT_RW;
  180 #ifdef COMPAT_FREEBSD32
  181 #if defined(__amd64__)
  182                 if (i386_read_exec && SV_PROC_FLAG(td->td_proc, SV_ILP32))
  183                         prot |= VM_PROT_EXECUTE;
  184 #endif
  185 #endif
  186                 rv = vm_map_insert(map, NULL, 0, old, new, prot, VM_PROT_ALL, 0);
  187                 if (rv != KERN_SUCCESS) {
  188 #ifdef RACCT
  189                         if (racct_enable) {
  190                                 PROC_LOCK(td->td_proc);
  191                                 racct_set_force(td->td_proc,
  192                                     RACCT_DATA, old - base);
  193                                 racct_set_force(td->td_proc,
  194                                     RACCT_VMEM, map->size);
  195                                 if (!old_mlock && map->flags & MAP_WIREFUTURE) {
  196                                         racct_set_force(td->td_proc,
  197                                             RACCT_MEMLOCK,
  198                                             ptoa(pmap_wired_count(map->pmap)));
  199                                 }
  200                                 PROC_UNLOCK(td->td_proc);
  201                         }
  202 #endif
  203                         error = ENOMEM;
  204                         goto done;
  205                 }
  206                 vm->vm_dsize += btoc(new - old);
  207                 /*
  208                  * Handle the MAP_WIREFUTURE case for legacy applications,
  209                  * by marking the newly mapped range of pages as wired.
  210                  * We are not required to perform a corresponding
  211                  * vm_map_unwire() before vm_map_delete() below, as
  212                  * it will forcibly unwire the pages in the range.
  213                  *
  214                  * XXX If the pages cannot be wired, no error is returned.
  215                  */
  216                 if ((map->flags & MAP_WIREFUTURE) == MAP_WIREFUTURE)
  217                         do_map_wirefuture = TRUE;
  218         } else if (new < old) {
  219                 rv = vm_map_delete(map, new, old);
  220                 if (rv != KERN_SUCCESS) {
  221                         error = ENOMEM;
  222                         goto done;
  223                 }
  224                 vm->vm_dsize -= btoc(old - new);
  225 #ifdef RACCT
  226                 if (racct_enable) {
  227                         PROC_LOCK(td->td_proc);
  228                         racct_set_force(td->td_proc, RACCT_DATA, new - base);
  229                         racct_set_force(td->td_proc, RACCT_VMEM, map->size);
  230                         if (!old_mlock && map->flags & MAP_WIREFUTURE) {
  231                                 racct_set_force(td->td_proc, RACCT_MEMLOCK,
  232                                     ptoa(pmap_wired_count(map->pmap)));
  233                         }
  234                         PROC_UNLOCK(td->td_proc);
  235                 }
  236 #endif
  237         }
  238 done:
  239         vm_map_unlock(map);
  240 
  241         if (do_map_wirefuture)
  242                 (void) vm_map_wire(map, old, new,
  243                     VM_MAP_WIRE_USER|VM_MAP_WIRE_NOHOLES);
  244 
  245         if (error == 0)
  246                 *addr = new;
  247 
  248         return (error);
  249 }
  250 
  251 #ifdef COMPAT_FREEBSD11
  252 int
  253 freebsd11_vadvise(struct thread *td, struct freebsd11_vadvise_args *uap)
  254 {
  255 
  256         return (EINVAL);
  257 }
  258 #endif
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FreeBSD/Linux Kernel Cross Reference sys/vm/vm_unix.c

FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_unix.c
