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uvm_unix.c revision 1.40
      1 /*	$NetBSD: uvm_unix.c,v 1.40 2008/01/02 11:49:21 ad Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1997 Charles D. Cranor and Washington University.
      5  * Copyright (c) 1991, 1993 The Regents of the University of California.
      6  * Copyright (c) 1988 University of Utah.
      7  *
      8  * All rights reserved.
      9  *
     10  * This code is derived from software contributed to Berkeley by
     11  * the Systems Programming Group of the University of Utah Computer
     12  * Science Department.
     13  *
     14  * Redistribution and use in source and binary forms, with or without
     15  * modification, are permitted provided that the following conditions
     16  * are met:
     17  * 1. Redistributions of source code must retain the above copyright
     18  *    notice, this list of conditions and the following disclaimer.
     19  * 2. Redistributions in binary form must reproduce the above copyright
     20  *    notice, this list of conditions and the following disclaimer in the
     21  *    documentation and/or other materials provided with the distribution.
     22  * 3. All advertising materials mentioning features or use of this software
     23  *    must display the following acknowledgement:
     24  *      This product includes software developed by Charles D. Cranor,
     25  *	Washington University, the University of California, Berkeley and
     26  *	its contributors.
     27  * 4. Neither the name of the University nor the names of its contributors
     28  *    may be used to endorse or promote products derived from this software
     29  *    without specific prior written permission.
     30  *
     31  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     32  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     33  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     34  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     35  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     39  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     40  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     41  * SUCH DAMAGE.
     42  *
     43  * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
     44  *      @(#)vm_unix.c   8.1 (Berkeley) 6/11/93
     45  * from: Id: uvm_unix.c,v 1.1.2.2 1997/08/25 18:52:30 chuck Exp
     46  */
     47 
     48 /*
     49  * uvm_unix.c: traditional sbrk/grow interface to vm.
     50  */
     51 
     52 #include <sys/cdefs.h>
     53 __KERNEL_RCSID(0, "$NetBSD: uvm_unix.c,v 1.40 2008/01/02 11:49:21 ad Exp $");
     54 
     55 #include "opt_pax.h"
     56 
     57 #include <sys/param.h>
     58 #include <sys/systm.h>
     59 #include <sys/proc.h>
     60 #include <sys/resourcevar.h>
     61 
     62 #include <sys/mount.h>
     63 #include <sys/syscallargs.h>
     64 
     65 #ifdef PAX_MPROTECT
     66 #include <sys/pax.h>
     67 #endif /* PAX_MPROTECT */
     68 
     69 #include <uvm/uvm.h>
     70 
     71 /*
     72  * sys_obreak: set break
     73  */
     74 
     75 int
     76 sys_obreak(struct lwp *l, const struct sys_obreak_args *uap, register_t *retval)
     77 {
     78 	/* {
     79 		syscallarg(char *) nsize;
     80 	} */
     81 	struct proc *p = l->l_proc;
     82 	struct vmspace *vm = p->p_vmspace;
     83 	vaddr_t new, old;
     84 	int error;
     85 
     86 	mutex_enter(&p->p_auxlock);
     87 	old = (vaddr_t)vm->vm_daddr;
     88 	new = round_page((vaddr_t)SCARG(uap, nsize));
     89 	if ((new - old) > p->p_rlimit[RLIMIT_DATA].rlim_cur && new > old) {
     90 		mutex_exit(&p->p_auxlock);
     91 		return (ENOMEM);
     92 	}
     93 
     94 	old = round_page(old + ptoa(vm->vm_dsize));
     95 
     96 	if (new == old) {
     97 		mutex_exit(&p->p_auxlock);
     98 		return (0);
     99 	}
    100 
    101 	/*
    102 	 * grow or shrink?
    103 	 */
    104 
    105 	if (new > old) {
    106 		vm_prot_t prot = UVM_PROT_READ | UVM_PROT_WRITE;
    107 		vm_prot_t maxprot = UVM_PROT_ALL;
    108 
    109 #ifdef PAX_MPROTECT
    110 		pax_mprotect(l, &prot, &maxprot);
    111 #endif /* PAX_MPROTECT */
    112 
    113 		error = uvm_map(&vm->vm_map, &old, new - old, NULL,
    114 		    UVM_UNKNOWN_OFFSET, 0,
    115 		    UVM_MAPFLAG(prot, maxprot,
    116 				UVM_INH_COPY,
    117 				UVM_ADV_NORMAL, UVM_FLAG_AMAPPAD|UVM_FLAG_FIXED|
    118 				UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW));
    119 		if (error) {
    120 			uprintf("sbrk: grow %ld failed, error = %d\n",
    121 				new - old, error);
    122 			mutex_exit(&p->p_auxlock);
    123 			return (error);
    124 		}
    125 		vm->vm_dsize += atop(new - old);
    126 	} else {
    127 		uvm_deallocate(&vm->vm_map, new, old - new);
    128 		vm->vm_dsize -= atop(old - new);
    129 	}
    130 	mutex_exit(&p->p_auxlock);
    131 
    132 	return (0);
    133 }
    134 
    135 /*
    136  * uvm_grow: enlarge the "stack segment" to include sp.
    137  */
    138 
    139 int
    140 uvm_grow(struct proc *p, vaddr_t sp)
    141 {
    142 	struct vmspace *vm = p->p_vmspace;
    143 	vsize_t nss;
    144 
    145 	/*
    146 	 * For user defined stacks (from sendsig).
    147 	 */
    148 #ifdef __MACHINE_STACK_GROWS_UP
    149 	if (sp < (vaddr_t)vm->vm_minsaddr)
    150 #else
    151 	if (sp < (vaddr_t)vm->vm_maxsaddr)
    152 #endif
    153 		return (0);
    154 
    155 	/*
    156 	 * For common case of already allocated (from trap).
    157 	 */
    158 #ifdef __MACHINE_STACK_GROWS_UP
    159 	if (sp < USRSTACK + ctob(vm->vm_ssize))
    160 #else
    161 	if (sp >= USRSTACK - ctob(vm->vm_ssize))
    162 #endif
    163 		return (1);
    164 
    165 	/*
    166 	 * Really need to check vs limit and increment stack size if ok.
    167 	 */
    168 #ifdef __MACHINE_STACK_GROWS_UP
    169 	nss = btoc(sp - USRSTACK);
    170 #else
    171 	nss = btoc(USRSTACK - sp);
    172 #endif
    173 	if (nss > btoc(p->p_rlimit[RLIMIT_STACK].rlim_cur))
    174 		return (0);
    175 	vm->vm_ssize = nss;
    176 	return (1);
    177 }
    178 
    179 /*
    180  * sys_oadvise: old advice system call
    181  */
    182 
    183 /* ARGSUSED */
    184 int
    185 sys_ovadvise(struct lwp *l, const struct sys_ovadvise_args *uap, register_t *retval)
    186 {
    187 #if 0
    188 	/* {
    189 		syscallarg(int) anom;
    190 	} */
    191 #endif
    192 
    193 	return (EINVAL);
    194 }
    195