939df36e55
and make the stack and heap non-executable by default. the changes fall into two basic catagories: - pmap and trap-handler changes. these are all MD: = alpha: we already track per-page execute permission with the (software) PG_EXEC bit, so just have the trap handler pay attention to it. = i386: use a new GDT segment for %cs for processes that have no executable mappings above a certain threshold (currently the bottom of the stack). track per-page execute permission with the last unused PTE bit. = powerpc/ibm4xx: just use the hardware exec bit. = powerpc/oea: we already track per-page exec bits, but the hardware only implements non-exec mappings at the segment level. so track the number of executable mappings in each segment and turn on the no-exec segment bit iff the count is 0. adjust the trap handler to deal. = sparc (sun4m): fix our use of the hardware protection bits. fix the trap handler to recognize text faults. = sparc64: split the existing unified TSB into data and instruction TSBs, and only load TTEs into the appropriate TSB(s) for the permissions. fix the trap handler to check for execute permission. = not yet implemented: amd64, hppa, sh5 - changes in all the emulations that put a signal trampoline on the stack. instead, we now put the trampoline into a uvm_aobj and map that into the process separately. originally from openbsd, adapted for netbsd by me.
172 lines
4.6 KiB
C
172 lines
4.6 KiB
C
/* $NetBSD: uvm_unix.c,v 1.29 2003/08/24 17:52:48 chs Exp $ */
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/*
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* Copyright (c) 1997 Charles D. Cranor and Washington University.
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* Copyright (c) 1991, 1993 The Regents of the University of California.
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* Copyright (c) 1988 University of Utah.
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*
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the Systems Programming Group of the University of Utah Computer
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* Science Department.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Charles D. Cranor,
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* Washington University, the University of California, Berkeley and
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* its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: Utah $Hdr: vm_unix.c 1.1 89/11/07$
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* @(#)vm_unix.c 8.1 (Berkeley) 6/11/93
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* from: Id: uvm_unix.c,v 1.1.2.2 1997/08/25 18:52:30 chuck Exp
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*/
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/*
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* uvm_unix.c: traditional sbrk/grow interface to vm.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: uvm_unix.c,v 1.29 2003/08/24 17:52:48 chs Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/sa.h>
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#include <sys/syscallargs.h>
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#include <uvm/uvm.h>
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/*
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* sys_obreak: set break
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*/
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int
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sys_obreak(l, v, retval)
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struct lwp *l;
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void *v;
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register_t *retval;
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{
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struct sys_obreak_args /* {
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syscallarg(char *) nsize;
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} */ *uap = v;
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struct proc *p = l->l_proc;
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struct vmspace *vm = p->p_vmspace;
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vaddr_t new, old;
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int error;
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old = (vaddr_t)vm->vm_daddr;
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new = round_page((vaddr_t)SCARG(uap, nsize));
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if ((new - old) > p->p_rlimit[RLIMIT_DATA].rlim_cur && new > old)
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return (ENOMEM);
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old = round_page(old + ptoa(vm->vm_dsize));
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if (new == old)
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return (0);
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/*
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* grow or shrink?
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*/
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if (new > old) {
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error = uvm_map(&vm->vm_map, &old, new - old, NULL,
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UVM_UNKNOWN_OFFSET, 0,
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UVM_MAPFLAG(UVM_PROT_READ | UVM_PROT_WRITE, UVM_PROT_ALL,
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UVM_INH_COPY,
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UVM_ADV_NORMAL, UVM_FLAG_AMAPPAD|UVM_FLAG_FIXED|
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UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW));
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if (error) {
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uprintf("sbrk: grow %ld failed, error = %d\n",
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new - old, error);
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return (error);
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}
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vm->vm_dsize += atop(new - old);
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} else {
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uvm_deallocate(&vm->vm_map, new, old - new);
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vm->vm_dsize -= atop(old - new);
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}
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return (0);
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}
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/*
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* uvm_grow: enlarge the "stack segment" to include sp.
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*/
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int
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uvm_grow(p, sp)
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struct proc *p;
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vaddr_t sp;
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{
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struct vmspace *vm = p->p_vmspace;
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int si;
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/*
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* For user defined stacks (from sendsig).
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*/
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if (sp < (vaddr_t)vm->vm_maxsaddr)
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return (0);
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/*
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* For common case of already allocated (from trap).
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*/
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if (sp >= USRSTACK - ctob(vm->vm_ssize))
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return (1);
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/*
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* Really need to check vs limit and increment stack size if ok.
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*/
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si = btoc(USRSTACK-sp) - vm->vm_ssize;
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if (vm->vm_ssize + si > btoc(p->p_rlimit[RLIMIT_STACK].rlim_cur))
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return (0);
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vm->vm_ssize += si;
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return (1);
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}
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/*
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* sys_oadvise: old advice system call
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*/
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/* ARGSUSED */
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int
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sys_ovadvise(l, v, retval)
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struct lwp *l;
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void *v;
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register_t *retval;
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{
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#if 0
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struct sys_ovadvise_args /* {
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syscallarg(int) anom;
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} */ *uap = v;
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#endif
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return (EINVAL);
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}
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