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uvm_unix.c revision 1.45
      1 /*	$NetBSD: uvm_unix.c,v 1.45 2014/09/05 05:36:49 matt 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. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  *
     38  * from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
     39  *      @(#)vm_unix.c   8.1 (Berkeley) 6/11/93
     40  * from: Id: uvm_unix.c,v 1.1.2.2 1997/08/25 18:52:30 chuck Exp
     41  */
     42 
     43 /*
     44  * uvm_unix.c: traditional sbrk/grow interface to vm.
     45  */
     46 
     47 #include <sys/cdefs.h>
     48 __KERNEL_RCSID(0, "$NetBSD: uvm_unix.c,v 1.45 2014/09/05 05:36:49 matt Exp $");
     49 
     50 #include "opt_pax.h"
     51 
     52 #include <sys/param.h>
     53 #include <sys/systm.h>
     54 #include <sys/proc.h>
     55 #include <sys/resourcevar.h>
     56 
     57 #include <sys/mount.h>
     58 #include <sys/syscallargs.h>
     59 
     60 #ifdef PAX_MPROTECT
     61 #include <sys/pax.h>
     62 #endif /* PAX_MPROTECT */
     63 
     64 #include <uvm/uvm.h>
     65 
     66 /*
     67  * sys_obreak: set break
     68  */
     69 
     70 int
     71 sys_obreak(struct lwp *l, const struct sys_obreak_args *uap, register_t *retval)
     72 {
     73 	/* {
     74 		syscallarg(char *) nsize;
     75 	} */
     76 	struct proc *p = l->l_proc;
     77 	struct vmspace *vm = p->p_vmspace;
     78 	vaddr_t nbreak, obreak;
     79 	int error;
     80 
     81 	mutex_enter(&p->p_auxlock);
     82 	obreak = (vaddr_t)vm->vm_daddr;
     83 	nbreak = round_page((vaddr_t)SCARG(uap, nsize));
     84 	if (nbreak == 0
     85 	    || ((nbreak - obreak) > p->p_rlimit[RLIMIT_DATA].rlim_cur
     86 		&& nbreak > obreak)) {
     87 		mutex_exit(&p->p_auxlock);
     88 		return (ENOMEM);
     89 	}
     90 
     91 	obreak = round_page(obreak + ptoa(vm->vm_dsize));
     92 
     93 	if (nbreak == obreak) {
     94 		mutex_exit(&p->p_auxlock);
     95 		return (0);
     96 	}
     97 
     98 	/*
     99 	 * grow or shrink?
    100 	 */
    101 
    102 	if (nbreak > obreak) {
    103 		vm_prot_t prot = UVM_PROT_READ | UVM_PROT_WRITE;
    104 		vm_prot_t maxprot = UVM_PROT_ALL;
    105 
    106 #ifdef PAX_MPROTECT
    107 		pax_mprotect(l, &prot, &maxprot);
    108 #endif /* PAX_MPROTECT */
    109 
    110 		error = uvm_map(&vm->vm_map, &obreak, nbreak - obreak, NULL,
    111 		    UVM_UNKNOWN_OFFSET, 0,
    112 		    UVM_MAPFLAG(prot, maxprot,
    113 				UVM_INH_COPY,
    114 				UVM_ADV_NORMAL, UVM_FLAG_AMAPPAD|UVM_FLAG_FIXED|
    115 				UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW));
    116 		if (error) {
    117 #ifdef DEBUG
    118 			uprintf("sbrk: grow %#"PRIxVADDR" failed, error = %d\n",
    119 			    nbreak - obreak, error);
    120 #endif
    121 			mutex_exit(&p->p_auxlock);
    122 			return (error);
    123 		}
    124 		vm->vm_dsize += atop(nbreak - obreak);
    125 	} else {
    126 		uvm_deallocate(&vm->vm_map, nbreak, obreak - nbreak);
    127 		vm->vm_dsize -= atop(obreak - nbreak);
    128 	}
    129 	mutex_exit(&p->p_auxlock);
    130 
    131 	return (0);
    132 }
    133 
    134 /*
    135  * uvm_grow: enlarge the "stack segment" to include sp.
    136  */
    137 
    138 int
    139 uvm_grow(struct proc *p, vaddr_t sp)
    140 {
    141 	struct vmspace *vm = p->p_vmspace;
    142 	vsize_t nss;
    143 
    144 	/*
    145 	 * For user defined stacks (from sendsig).
    146 	 */
    147 #ifdef __MACHINE_STACK_GROWS_UP
    148 	if (sp < (vaddr_t)vm->vm_minsaddr)
    149 #else
    150 	if (sp < (vaddr_t)vm->vm_maxsaddr)
    151 #endif
    152 		return (0);
    153 
    154 	/*
    155 	 * For common case of already allocated (from trap).
    156 	 */
    157 #ifdef __MACHINE_STACK_GROWS_UP
    158 	if (sp < USRSTACK + ctob(vm->vm_ssize))
    159 #else
    160 	if (sp >= USRSTACK - ctob(vm->vm_ssize))
    161 #endif
    162 		return (1);
    163 
    164 	/*
    165 	 * Really need to check vs limit and increment stack size if ok.
    166 	 */
    167 #ifdef __MACHINE_STACK_GROWS_UP
    168 	nss = btoc(sp - USRSTACK);
    169 #else
    170 	nss = btoc(USRSTACK - sp);
    171 #endif
    172 	if (nss > btoc(p->p_rlimit[RLIMIT_STACK].rlim_cur))
    173 		return (0);
    174 	vm->vm_ssize = nss;
    175 	return (1);
    176 }
    177 
    178 /*
    179  * sys_oadvise: old advice system call
    180  */
    181 
    182 /* ARGSUSED */
    183 int
    184 sys_ovadvise(struct lwp *l, const struct sys_ovadvise_args *uap, register_t *retval)
    185 {
    186 #if 0
    187 	/* {
    188 		syscallarg(int) anom;
    189 	} */
    190 #endif
    191 
    192 	return (EINVAL);
    193 }
    194