/*      $NetBSD: uvm_unix.c,v 1.51 2022/01/10 18:04:20 christos 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. 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 1.51 2022/01/10 18:04:20 christos 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>
#include <sys/pax.h>

#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 nbreak, obreak;
       int error;

       mutex_enter(&p->p_auxlock);
       obreak = (vaddr_t)vm->vm_daddr;
       nbreak = round_page((vaddr_t)SCARG(uap, nsize));
       if (nbreak == 0
           || ((nbreak - obreak) > p->p_rlimit[RLIMIT_DATA].rlim_cur
               && nbreak > obreak)) {
               mutex_exit(&p->p_auxlock);
               return (ENOMEM);
       }

       obreak = round_page(obreak + ptoa(vm->vm_dsize));

       if (nbreak == obreak) {
               mutex_exit(&p->p_auxlock);
               return (0);
       }

       /*
        * grow or shrink?
        */

       if (nbreak > obreak) {
               vm_prot_t prot = UVM_PROT_RW;
               vm_prot_t maxprot;

               maxprot = PAX_MPROTECT_MAXPROTECT(l, prot, 0, UVM_PROT_ALL);

               error = uvm_map(&vm->vm_map, &obreak, nbreak - obreak, 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) {
#ifdef DEBUG
                       uprintf("sbrk: grow %#"PRIxVADDR" failed, error = %d\n",
                           nbreak - obreak, error);
#endif
                       mutex_exit(&p->p_auxlock);
                       return (error);
               }
               vm->vm_dsize += atop(nbreak - obreak);
       } else {
               uvm_deallocate(&vm->vm_map, nbreak, obreak - nbreak);
               vm->vm_dsize -= atop(obreak - nbreak);
       }
       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 < p->p_stackbase + ctob(vm->vm_ssize))
#else
       if (sp >= p->p_stackbase - 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 - p->p_stackbase);
#else
       nss = btoc(p->p_stackbase - 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);
}