FreeBSD/Linux Kernel Cross Reference
sys/uvm/uvm_unix.c

     /*      $NetBSD: uvm_unix.c,v 1.40 2008/01/02 11:49:21 ad Exp $ */
     
     /*
      * Copyright (c) 1997 Charles D. Cranor and Washington University.
      * Copyright (c) 1991, 1993 The Regents of the University of California.
      * Copyright (c) 1988 University of Utah.
      *
      * All rights reserved.
      *
     * This code is derived from software contributed to Berkeley by
     * the Systems Programming Group of the University of Utah Computer
     * Science Department.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by Charles D. Cranor,
     *      Washington University, the University of California, Berkeley and
     *      its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
     *      @(#)vm_unix.c   8.1 (Berkeley) 6/11/93
     * from: Id: uvm_unix.c,v 1.1.2.2 1997/08/25 18:52:30 chuck Exp
     */
    
    /*
     * uvm_unix.c: traditional sbrk/grow interface to vm.
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: uvm_unix.c,v 1.40 2008/01/02 11:49:21 ad Exp $");
    
    #include "opt_pax.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/proc.h>
    #include <sys/resourcevar.h>
    
    #include <sys/mount.h>
    #include <sys/syscallargs.h>
    
    #ifdef PAX_MPROTECT
    #include <sys/pax.h>
    #endif /* PAX_MPROTECT */
    
    #include <uvm/uvm.h>
    
    /*
     * sys_obreak: set break
     */
    
    int
    sys_obreak(struct lwp *l, const struct sys_obreak_args *uap, register_t *retval)
    {
            /* {
                    syscallarg(char *) nsize;
            } */
            struct proc *p = l->l_proc;
            struct vmspace *vm = p->p_vmspace;
            vaddr_t new, old;
            int error;
    
            mutex_enter(&p->p_auxlock);
            old = (vaddr_t)vm->vm_daddr;
            new = round_page((vaddr_t)SCARG(uap, nsize));
            if ((new - old) > p->p_rlimit[RLIMIT_DATA].rlim_cur && new > old) {
                    mutex_exit(&p->p_auxlock);
                    return (ENOMEM);
            }
    
            old = round_page(old + ptoa(vm->vm_dsize));
    
            if (new == old) {
                    mutex_exit(&p->p_auxlock);
                    return (0);
            }
   
           /*
            * grow or shrink?
            */
   
           if (new > old) {
                   vm_prot_t prot = UVM_PROT_READ | UVM_PROT_WRITE;
                   vm_prot_t maxprot = UVM_PROT_ALL;
   
   #ifdef PAX_MPROTECT
                   pax_mprotect(l, &prot, &maxprot);
   #endif /* PAX_MPROTECT */
   
                   error = uvm_map(&vm->vm_map, &old, new - old, NULL,
                       UVM_UNKNOWN_OFFSET, 0,
                       UVM_MAPFLAG(prot, maxprot,
                                   UVM_INH_COPY,
                                   UVM_ADV_NORMAL, UVM_FLAG_AMAPPAD|UVM_FLAG_FIXED|
                                   UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW));
                   if (error) {
                           uprintf("sbrk: grow %ld failed, error = %d\n",
                                   new - old, error);
                           mutex_exit(&p->p_auxlock);
                           return (error);
                   }
                   vm->vm_dsize += atop(new - old);
           } else {
                   uvm_deallocate(&vm->vm_map, new, old - new);
                   vm->vm_dsize -= atop(old - new);
           }
           mutex_exit(&p->p_auxlock);
   
           return (0);
   }
   
   /*
    * uvm_grow: enlarge the "stack segment" to include sp.
    */
   
   int
   uvm_grow(struct proc *p, vaddr_t sp)
   {
           struct vmspace *vm = p->p_vmspace;
           vsize_t nss;
   
           /*
            * For user defined stacks (from sendsig).
            */
   #ifdef __MACHINE_STACK_GROWS_UP
           if (sp < (vaddr_t)vm->vm_minsaddr)
   #else
           if (sp < (vaddr_t)vm->vm_maxsaddr)
   #endif
                   return (0);
   
           /*
            * For common case of already allocated (from trap).
            */
   #ifdef __MACHINE_STACK_GROWS_UP
           if (sp < USRSTACK + ctob(vm->vm_ssize))
   #else
           if (sp >= USRSTACK - ctob(vm->vm_ssize))
   #endif
                   return (1);
   
           /*
            * Really need to check vs limit and increment stack size if ok.
            */
   #ifdef __MACHINE_STACK_GROWS_UP
           nss = btoc(sp - USRSTACK);
   #else
           nss = btoc(USRSTACK - sp);
   #endif
           if (nss > btoc(p->p_rlimit[RLIMIT_STACK].rlim_cur))
                   return (0);
           vm->vm_ssize = nss;
           return (1);
   }
   
   /*
    * sys_oadvise: old advice system call
    */
   
   /* ARGSUSED */
   int
   sys_ovadvise(struct lwp *l, const struct sys_ovadvise_args *uap, register_t *retval)
   {
   #if 0
           /* {
                   syscallarg(int) anom;
           } */
   #endif
   
           return (EINVAL);
   }

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