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[netbsd-mini2440.git] / sys / uvm / uvm_mmap.c

/*      $NetBSD: uvm_mmap.c,v 1.131 2009/08/18 02:41:31 yamt 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 the Charles D. Cranor,
 *      Washington University, 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 $Hdr: vm_mmap.c 1.6 91/10/21$
 *      @(#)vm_mmap.c   8.5 (Berkeley) 5/19/94
 * from: Id: uvm_mmap.c,v 1.1.2.14 1998/01/05 21:04:26 chuck Exp
 */

/*
 * uvm_mmap.c: system call interface into VM system, plus kernel vm_mmap
 * function.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_mmap.c,v 1.131 2009/08/18 02:41:31 yamt Exp $");

#include "opt_compat_netbsd.h"
#include "opt_pax.h"
#include "veriexec.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/resourcevar.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/conf.h>
#include <sys/stat.h>

#if NVERIEXEC > 0
#include <sys/verified_exec.h>
#endif /* NVERIEXEC > 0 */
 
#ifdef PAX_MPROTECT
#include <sys/pax.h>
#endif /* PAX_MPROTECT */

#include <miscfs/specfs/specdev.h>

#include <sys/syscallargs.h>

#include <uvm/uvm.h>
#include <uvm/uvm_device.h>

#ifndef COMPAT_ZERODEV
#define COMPAT_ZERODEV(dev)     (0)
#endif

static int
range_test(vaddr_t addr, vsize_t size, bool ismmap)
{
        vaddr_t vm_min_address = VM_MIN_ADDRESS;
        vaddr_t vm_max_address = VM_MAXUSER_ADDRESS;
        vaddr_t eaddr = addr + size;

        if (addr < vm_min_address)
                return EINVAL;
        if (eaddr > vm_max_address)
                return ismmap ? EFBIG : EINVAL;
        if (addr > eaddr) /* no wrapping! */
                return ismmap ? EOVERFLOW : EINVAL;
        return 0;
}

/*
 * unimplemented VM system calls:
 */

/*
 * sys_sbrk: sbrk system call.
 */

/* ARGSUSED */
int
sys_sbrk(struct lwp *l, const struct sys_sbrk_args *uap, register_t *retval)
{
        /* {
                syscallarg(intptr_t) incr;
        } */

        return (ENOSYS);
}

/*
 * sys_sstk: sstk system call.
 */

/* ARGSUSED */
int
sys_sstk(struct lwp *l, const struct sys_sstk_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) incr;
        } */

        return (ENOSYS);
}

/*
 * sys_mincore: determine if pages are in core or not.
 */

/* ARGSUSED */
int
sys_mincore(struct lwp *l, const struct sys_mincore_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(void *) addr;
                syscallarg(size_t) len;
                syscallarg(char *) vec;
        } */
        struct proc *p = l->l_proc;
        struct vm_page *pg;
        char *vec, pgi;
        struct uvm_object *uobj;
        struct vm_amap *amap;
        struct vm_anon *anon;
        struct vm_map_entry *entry;
        vaddr_t start, end, lim;
        struct vm_map *map;
        vsize_t len;
        int error = 0, npgs;

        map = &p->p_vmspace->vm_map;

        start = (vaddr_t)SCARG(uap, addr);
        len = SCARG(uap, len);
        vec = SCARG(uap, vec);

        if (start & PAGE_MASK)
                return (EINVAL);
        len = round_page(len);
        end = start + len;
        if (end <= start)
                return (EINVAL);

        /*
         * Lock down vec, so our returned status isn't outdated by
         * storing the status byte for a page.
         */

        npgs = len >> PAGE_SHIFT;
        error = uvm_vslock(p->p_vmspace, vec, npgs, VM_PROT_WRITE);
        if (error) {
                return error;
        }
        vm_map_lock_read(map);

        if (uvm_map_lookup_entry(map, start, &entry) == false) {
                error = ENOMEM;
                goto out;
        }

        for (/* nothing */;
             entry != &map->header && entry->start < end;
             entry = entry->next) {
                KASSERT(!UVM_ET_ISSUBMAP(entry));
                KASSERT(start >= entry->start);

                /* Make sure there are no holes. */
                if (entry->end < end &&
                     (entry->next == &map->header ||
                      entry->next->start > entry->end)) {
                        error = ENOMEM;
                        goto out;
                }

                lim = end < entry->end ? end : entry->end;

                /*
                 * Special case for objects with no "real" pages.  Those
                 * are always considered resident (mapped devices).
                 */

                if (UVM_ET_ISOBJ(entry)) {
                        KASSERT(!UVM_OBJ_IS_KERN_OBJECT(entry->object.uvm_obj));
                        if (UVM_OBJ_IS_DEVICE(entry->object.uvm_obj)) {
                                for (/* nothing */; start < lim;
                                     start += PAGE_SIZE, vec++)
                                        subyte(vec, 1);
                                continue;
                        }
                }

                amap = entry->aref.ar_amap;     /* upper layer */
                uobj = entry->object.uvm_obj;   /* lower layer */

                if (amap != NULL)
                        amap_lock(amap);
                if (uobj != NULL)
                        mutex_enter(&uobj->vmobjlock);

                for (/* nothing */; start < lim; start += PAGE_SIZE, vec++) {
                        pgi = 0;
                        if (amap != NULL) {
                                /* Check the upper layer first. */
                                anon = amap_lookup(&entry->aref,
                                    start - entry->start);
                                /* Don't need to lock anon here. */
                                if (anon != NULL && anon->an_page != NULL) {

                                        /*
                                         * Anon has the page for this entry
                                         * offset.
                                         */

                                        pgi = 1;
                                }
                        }
                        if (uobj != NULL && pgi == 0) {
                                /* Check the lower layer. */
                                pg = uvm_pagelookup(uobj,
                                    entry->offset + (start - entry->start));
                                if (pg != NULL) {

                                        /*
                                         * Object has the page for this entry
                                         * offset.
                                         */

                                        pgi = 1;
                                }
                        }
                        (void) subyte(vec, pgi);
                }
                if (uobj != NULL)
                        mutex_exit(&uobj->vmobjlock);
                if (amap != NULL)
                        amap_unlock(amap);
        }

 out:
        vm_map_unlock_read(map);
        uvm_vsunlock(p->p_vmspace, SCARG(uap, vec), npgs);
        return (error);
}

/*
 * sys_mmap: mmap system call.
 *
 * => file offset and address may not be page aligned
 *    - if MAP_FIXED, offset and address must have remainder mod PAGE_SIZE
 *    - if address isn't page aligned the mapping starts at trunc_page(addr)
 *      and the return value is adjusted up by the page offset.
 */

int
sys_mmap(struct lwp *l, const struct sys_mmap_args *uap, register_t *retval)
{
        /* {
                syscallarg(void *) addr;
                syscallarg(size_t) len;
                syscallarg(int) prot;
                syscallarg(int) flags;
                syscallarg(int) fd;
                syscallarg(long) pad;
                syscallarg(off_t) pos;
        } */
        struct proc *p = l->l_proc;
        vaddr_t addr;
        struct vattr va;
        off_t pos;
        vsize_t size, pageoff;
        vm_prot_t prot, maxprot;
        int flags, fd;
        vaddr_t defaddr;
        struct file *fp = NULL;
        struct vnode *vp;
        void *handle;
        int error;
#ifdef PAX_ASLR
        vaddr_t orig_addr;
#endif /* PAX_ASLR */

        /*
         * first, extract syscall args from the uap.
         */

        addr = (vaddr_t)SCARG(uap, addr);
        size = (vsize_t)SCARG(uap, len);
        prot = SCARG(uap, prot) & VM_PROT_ALL;
        flags = SCARG(uap, flags);
        fd = SCARG(uap, fd);
        pos = SCARG(uap, pos);

#ifdef PAX_ASLR
        orig_addr = addr;
#endif /* PAX_ASLR */

        /*
         * Fixup the old deprecated MAP_COPY into MAP_PRIVATE, and
         * validate the flags.
         */
        if (flags & MAP_COPY)
                flags = (flags & ~MAP_COPY) | MAP_PRIVATE;
        if ((flags & (MAP_SHARED|MAP_PRIVATE)) == (MAP_SHARED|MAP_PRIVATE))
                return (EINVAL);

        /*
         * align file position and save offset.  adjust size.
         */

        pageoff = (pos & PAGE_MASK);
        pos  -= pageoff;
        size += pageoff;                        /* add offset */
        size = (vsize_t)round_page(size);       /* round up */

        /*
         * now check (MAP_FIXED) or get (!MAP_FIXED) the "addr"
         */
        if (flags & MAP_FIXED) {

                /* ensure address and file offset are aligned properly */
                addr -= pageoff;
                if (addr & PAGE_MASK)
                        return (EINVAL);

                error = range_test(addr, size, true);
                if (error)
                        return error;
        } else if (addr == 0 || !(flags & MAP_TRYFIXED)) {

                /*
                 * not fixed: make sure we skip over the largest
                 * possible heap for non-topdown mapping arrangements.
                 * we will refine our guess later (e.g. to account for
                 * VAC, etc)
                 */

                defaddr = p->p_emul->e_vm_default_addr(p,
                    (vaddr_t)p->p_vmspace->vm_daddr, size);

                if (addr == 0 ||
                    !(p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN))
                        addr = MAX(addr, defaddr);
                else
                        addr = MIN(addr, defaddr);
        }

        /*
         * check for file mappings (i.e. not anonymous) and verify file.
         */

        if ((flags & MAP_ANON) == 0) {
                if ((fp = fd_getfile(fd)) == NULL)
                        return (EBADF);
                if (fp->f_type != DTYPE_VNODE) {
                        fd_putfile(fd);
                        return (ENODEV);                /* only mmap vnodes! */
                }
                vp = fp->f_data;                /* convert to vnode */
                if (vp->v_type != VREG && vp->v_type != VCHR &&
                    vp->v_type != VBLK) {
                        fd_putfile(fd);
                        return (ENODEV);  /* only REG/CHR/BLK support mmap */
                }
                if (vp->v_type != VCHR && pos < 0) {
                        fd_putfile(fd);
                        return (EINVAL);
                }
                if (vp->v_type != VCHR && (pos + size) < pos) {
                        fd_putfile(fd);
                        return (EOVERFLOW);             /* no offset wrapping */
                }

                /* special case: catch SunOS style /dev/zero */
                if (vp->v_type == VCHR
                    && (vp->v_rdev == zerodev || COMPAT_ZERODEV(vp->v_rdev))) {
                        flags |= MAP_ANON;
                        fd_putfile(fd);
                        fp = NULL;
                        goto is_anon;
                }

                /*
                 * Old programs may not select a specific sharing type, so
                 * default to an appropriate one.
                 *
                 * XXX: how does MAP_ANON fit in the picture?
                 */
                if ((flags & (MAP_SHARED|MAP_PRIVATE)) == 0) {
#if defined(DEBUG)
                        printf("WARNING: defaulted mmap() share type to "
                           "%s (pid %d command %s)\n", vp->v_type == VCHR ?
                           "MAP_SHARED" : "MAP_PRIVATE", p->p_pid,
                            p->p_comm);
#endif
                        if (vp->v_type == VCHR)
                                flags |= MAP_SHARED;    /* for a device */
                        else
                                flags |= MAP_PRIVATE;   /* for a file */
                }

                /*
                 * MAP_PRIVATE device mappings don't make sense (and aren't
                 * supported anyway).  However, some programs rely on this,
                 * so just change it to MAP_SHARED.
                 */
                if (vp->v_type == VCHR && (flags & MAP_PRIVATE) != 0) {
                        flags = (flags & ~MAP_PRIVATE) | MAP_SHARED;
                }

                /*
                 * now check protection
                 */

                maxprot = VM_PROT_EXECUTE;

                /* check read access */
                if (fp->f_flag & FREAD)
                        maxprot |= VM_PROT_READ;
                else if (prot & PROT_READ) {
                        fd_putfile(fd);
                        return (EACCES);
                }

                /* check write access, shared case first */
                if (flags & MAP_SHARED) {
                        /*
                         * if the file is writable, only add PROT_WRITE to
                         * maxprot if the file is not immutable, append-only.
                         * otherwise, if we have asked for PROT_WRITE, return
                         * EPERM.
                         */
                        if (fp->f_flag & FWRITE) {
                                if ((error =
                                    VOP_GETATTR(vp, &va, l->l_cred))) {
                                        fd_putfile(fd);
                                        return (error);
                                }
                                if ((va.va_flags &
                                    (SF_SNAPSHOT|IMMUTABLE|APPEND)) == 0)
                                        maxprot |= VM_PROT_WRITE;
                                else if (prot & PROT_WRITE) {
                                        fd_putfile(fd);
                                        return (EPERM);
                                }
                        }
                        else if (prot & PROT_WRITE) {
                                fd_putfile(fd);
                                return (EACCES);
                        }
                } else {
                        /* MAP_PRIVATE mappings can always write to */
                        maxprot |= VM_PROT_WRITE;
                }
                handle = vp;

        } else {                /* MAP_ANON case */
                /*
                 * XXX What do we do about (MAP_SHARED|MAP_PRIVATE) == 0?
                 */
                if (fd != -1)
                        return (EINVAL);

 is_anon:               /* label for SunOS style /dev/zero */
                handle = NULL;
                maxprot = VM_PROT_ALL;
                pos = 0;
        }

#if NVERIEXEC > 0
        if (handle != NULL) {
                /*
                 * Check if the file can be executed indirectly.
                 *
                 * XXX: This gives false warnings about "Incorrect access type"
                 * XXX: if the mapping is not executable. Harmless, but will be
                 * XXX: fixed as part of other changes.
                 */
                if (veriexec_verify(l, handle, "(mmap)", VERIEXEC_INDIRECT,
                    NULL)) {
                        /*
                         * Don't allow executable mappings if we can't
                         * indirectly execute the file.
                         */
                        if (prot & VM_PROT_EXECUTE) {
                                if (fp != NULL)
                                        fd_putfile(fd);
                                return (EPERM);
                        }

                        /*
                         * Strip the executable bit from 'maxprot' to make sure
                         * it can't be made executable later.
                         */
                        maxprot &= ~VM_PROT_EXECUTE;
                }
        }
#endif /* NVERIEXEC > 0 */

#ifdef PAX_MPROTECT
        pax_mprotect(l, &prot, &maxprot);
#endif /* PAX_MPROTECT */

#ifdef PAX_ASLR
        pax_aslr(l, &addr, orig_addr, flags);
#endif /* PAX_ASLR */

        /*
         * now let kernel internal function uvm_mmap do the work.
         */

        error = uvm_mmap(&p->p_vmspace->vm_map, &addr, size, prot, maxprot,
            flags, handle, pos, p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);

        if (error == 0)
                /* remember to add offset */
                *retval = (register_t)(addr + pageoff);

        if (fp != NULL)
                fd_putfile(fd);

        return (error);
}

/*
 * sys___msync13: the msync system call (a front-end for flush)
 */

int
sys___msync13(struct lwp *l, const struct sys___msync13_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(void *) addr;
                syscallarg(size_t) len;
                syscallarg(int) flags;
        } */
        struct proc *p = l->l_proc;
        vaddr_t addr;
        vsize_t size, pageoff;
        struct vm_map *map;
        int error, rv, flags, uvmflags;

        /*
         * extract syscall args from the uap
         */

        addr = (vaddr_t)SCARG(uap, addr);
        size = (vsize_t)SCARG(uap, len);
        flags = SCARG(uap, flags);

        /* sanity check flags */
        if ((flags & ~(MS_ASYNC | MS_SYNC | MS_INVALIDATE)) != 0 ||
            (flags & (MS_ASYNC | MS_SYNC | MS_INVALIDATE)) == 0 ||
            (flags & (MS_ASYNC | MS_SYNC)) == (MS_ASYNC | MS_SYNC))
                return (EINVAL);
        if ((flags & (MS_ASYNC | MS_SYNC)) == 0)
                flags |= MS_SYNC;

        /*
         * align the address to a page boundary and adjust the size accordingly.
         */

        pageoff = (addr & PAGE_MASK);
        addr -= pageoff;
        size += pageoff;
        size = (vsize_t)round_page(size);

        error = range_test(addr, size, false);
        if (error)
                return error;

        /*
         * get map
         */

        map = &p->p_vmspace->vm_map;

        /*
         * XXXCDC: do we really need this semantic?
         *
         * XXX Gak!  If size is zero we are supposed to sync "all modified
         * pages with the region containing addr".  Unfortunately, we
         * don't really keep track of individual mmaps so we approximate
         * by flushing the range of the map entry containing addr.
         * This can be incorrect if the region splits or is coalesced
         * with a neighbor.
         */

        if (size == 0) {
                struct vm_map_entry *entry;

                vm_map_lock_read(map);
                rv = uvm_map_lookup_entry(map, addr, &entry);
                if (rv == true) {
                        addr = entry->start;
                        size = entry->end - entry->start;
                }
                vm_map_unlock_read(map);
                if (rv == false)
                        return (EINVAL);
        }

        /*
         * translate MS_ flags into PGO_ flags
         */

        uvmflags = PGO_CLEANIT;
        if (flags & MS_INVALIDATE)
                uvmflags |= PGO_FREE;
        if (flags & MS_SYNC)
                uvmflags |= PGO_SYNCIO;

        error = uvm_map_clean(map, addr, addr+size, uvmflags);
        return error;
}

/*
 * sys_munmap: unmap a users memory
 */

int
sys_munmap(struct lwp *l, const struct sys_munmap_args *uap, register_t *retval)
{
        /* {
                syscallarg(void *) addr;
                syscallarg(size_t) len;
        } */
        struct proc *p = l->l_proc;
        vaddr_t addr;
        vsize_t size, pageoff;
        struct vm_map *map;
        struct vm_map_entry *dead_entries;
        int error;

        /*
         * get syscall args.
         */

        addr = (vaddr_t)SCARG(uap, addr);
        size = (vsize_t)SCARG(uap, len);

        /*
         * align the address to a page boundary and adjust the size accordingly.
         */

        pageoff = (addr & PAGE_MASK);
        addr -= pageoff;
        size += pageoff;
        size = (vsize_t)round_page(size);

        if (size == 0)
                return (0);

        error = range_test(addr, size, false);
        if (error)
                return error;

        map = &p->p_vmspace->vm_map;

        /*
         * interesting system call semantic: make sure entire range is
         * allocated before allowing an unmap.
         */

        vm_map_lock(map);
#if 0
        if (!uvm_map_checkprot(map, addr, addr + size, VM_PROT_NONE)) {
                vm_map_unlock(map);
                return (EINVAL);
        }
#endif
        uvm_unmap_remove(map, addr, addr + size, &dead_entries, NULL, 0);
        vm_map_unlock(map);
        if (dead_entries != NULL)
                uvm_unmap_detach(dead_entries, 0);
        return (0);
}

/*
 * sys_mprotect: the mprotect system call
 */

int
sys_mprotect(struct lwp *l, const struct sys_mprotect_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(void *) addr;
                syscallarg(size_t) len;
                syscallarg(int) prot;
        } */
        struct proc *p = l->l_proc;
        vaddr_t addr;
        vsize_t size, pageoff;
        vm_prot_t prot;
        int error;

        /*
         * extract syscall args from uap
         */

        addr = (vaddr_t)SCARG(uap, addr);
        size = (vsize_t)SCARG(uap, len);
        prot = SCARG(uap, prot) & VM_PROT_ALL;

        /*
         * align the address to a page boundary and adjust the size accordingly.
         */

        pageoff = (addr & PAGE_MASK);
        addr -= pageoff;
        size += pageoff;
        size = round_page(size);

        error = range_test(addr, size, false);
        if (error)
                return error;

        error = uvm_map_protect(&p->p_vmspace->vm_map, addr, addr + size, prot,
                                false);
        return error;
}

/*
 * sys_minherit: the minherit system call
 */

int
sys_minherit(struct lwp *l, const struct sys_minherit_args *uap,
   register_t *retval)
{
        /* {
                syscallarg(void *) addr;
                syscallarg(int) len;
                syscallarg(int) inherit;
        } */
        struct proc *p = l->l_proc;
        vaddr_t addr;
        vsize_t size, pageoff;
        vm_inherit_t inherit;
        int error;

        addr = (vaddr_t)SCARG(uap, addr);
        size = (vsize_t)SCARG(uap, len);
        inherit = SCARG(uap, inherit);

        /*
         * align the address to a page boundary and adjust the size accordingly.
         */

        pageoff = (addr & PAGE_MASK);
        addr -= pageoff;
        size += pageoff;
        size = (vsize_t)round_page(size);

        error = range_test(addr, size, false);
        if (error)
                return error;

        error = uvm_map_inherit(&p->p_vmspace->vm_map, addr, addr + size,
                                inherit);
        return error;
}

/*
 * sys_madvise: give advice about memory usage.
 */

/* ARGSUSED */
int
sys_madvise(struct lwp *l, const struct sys_madvise_args *uap,
   register_t *retval)
{
        /* {
                syscallarg(void *) addr;
                syscallarg(size_t) len;
                syscallarg(int) behav;
        } */
        struct proc *p = l->l_proc;
        vaddr_t addr;
        vsize_t size, pageoff;
        int advice, error;

        addr = (vaddr_t)SCARG(uap, addr);
        size = (vsize_t)SCARG(uap, len);
        advice = SCARG(uap, behav);

        /*
         * align the address to a page boundary, and adjust the size accordingly
         */

        pageoff = (addr & PAGE_MASK);
        addr -= pageoff;
        size += pageoff;
        size = (vsize_t)round_page(size);

        error = range_test(addr, size, false);
        if (error)
                return error;

        switch (advice) {
        case MADV_NORMAL:
        case MADV_RANDOM:
        case MADV_SEQUENTIAL:
                error = uvm_map_advice(&p->p_vmspace->vm_map, addr, addr + size,
                    advice);
                break;

        case MADV_WILLNEED:

                /*
                 * Activate all these pages, pre-faulting them in if
                 * necessary.
                 */
                error = uvm_map_willneed(&p->p_vmspace->vm_map,
                    addr, addr + size);
                break;

        case MADV_DONTNEED:

                /*
                 * Deactivate all these pages.  We don't need them
                 * any more.  We don't, however, toss the data in
                 * the pages.
                 */

                error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size,
                    PGO_DEACTIVATE);
                break;

        case MADV_FREE:

                /*
                 * These pages contain no valid data, and may be
                 * garbage-collected.  Toss all resources, including
                 * any swap space in use.
                 */

                error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size,
                    PGO_FREE);
                break;

        case MADV_SPACEAVAIL:

                /*
                 * XXXMRG What is this?  I think it's:
                 *
                 *      Ensure that we have allocated backing-store
                 *      for these pages.
                 *
                 * This is going to require changes to the page daemon,
                 * as it will free swap space allocated to pages in core.
                 * There's also what to do for device/file/anonymous memory.
                 */

                return (EINVAL);

        default:
                return (EINVAL);
        }

        return error;
}

/*
 * sys_mlock: memory lock
 */

int
sys_mlock(struct lwp *l, const struct sys_mlock_args *uap, register_t *retval)
{
        /* {
                syscallarg(const void *) addr;
                syscallarg(size_t) len;
        } */
        struct proc *p = l->l_proc;
        vaddr_t addr;
        vsize_t size, pageoff;
        int error;

        /*
         * extract syscall args from uap
         */

        addr = (vaddr_t)SCARG(uap, addr);
        size = (vsize_t)SCARG(uap, len);

        /*
         * align the address to a page boundary and adjust the size accordingly
         */

        pageoff = (addr & PAGE_MASK);
        addr -= pageoff;
        size += pageoff;
        size = (vsize_t)round_page(size);

        error = range_test(addr, size, false);
        if (error)
                return error;

        if (atop(size) + uvmexp.wired > uvmexp.wiredmax)
                return (EAGAIN);

        if (size + ptoa(pmap_wired_count(vm_map_pmap(&p->p_vmspace->vm_map))) >
                        p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur)
                return (EAGAIN);

        error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, false,
            0);
        if (error == EFAULT)
                error = ENOMEM;
        return error;
}

/*
 * sys_munlock: unlock wired pages
 */

int
sys_munlock(struct lwp *l, const struct sys_munlock_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(const void *) addr;
                syscallarg(size_t) len;
        } */
        struct proc *p = l->l_proc;
        vaddr_t addr;
        vsize_t size, pageoff;
        int error;

        /*
         * extract syscall args from uap
         */

        addr = (vaddr_t)SCARG(uap, addr);
        size = (vsize_t)SCARG(uap, len);

        /*
         * align the address to a page boundary, and adjust the size accordingly
         */

        pageoff = (addr & PAGE_MASK);
        addr -= pageoff;
        size += pageoff;
        size = (vsize_t)round_page(size);

        error = range_test(addr, size, false);
        if (error)
                return error;

        error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, true,
            0);
        if (error == EFAULT)
                error = ENOMEM;
        return error;
}

/*
 * sys_mlockall: lock all pages mapped into an address space.
 */

int
sys_mlockall(struct lwp *l, const struct sys_mlockall_args *uap,
    register_t *retval)
{
        /* {
                syscallarg(int) flags;
        } */
        struct proc *p = l->l_proc;
        int error, flags;

        flags = SCARG(uap, flags);

        if (flags == 0 ||
            (flags & ~(MCL_CURRENT|MCL_FUTURE)) != 0)
                return (EINVAL);

        error = uvm_map_pageable_all(&p->p_vmspace->vm_map, flags,
            p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
        return (error);
}

/*
 * sys_munlockall: unlock all pages mapped into an address space.
 */

int
sys_munlockall(struct lwp *l, const void *v, register_t *retval)
{
        struct proc *p = l->l_proc;

        (void) uvm_map_pageable_all(&p->p_vmspace->vm_map, 0, 0);
        return (0);
}

/*
 * uvm_mmap: internal version of mmap
 *
 * - used by sys_mmap and various framebuffers
 * - handle is a vnode pointer or NULL for MAP_ANON
 * - caller must page-align the file offset
 */

int
uvm_mmap(struct vm_map *map, vaddr_t *addr, vsize_t size, vm_prot_t prot,
    vm_prot_t maxprot, int flags, void *handle, voff_t foff, vsize_t locklimit)
{
        struct uvm_object *uobj;
        struct vnode *vp;
        vaddr_t align = 0;
        int error;
        int advice = UVM_ADV_NORMAL;
        uvm_flag_t uvmflag = 0;
        bool needwritemap;

        /*
         * check params
         */

        if (size == 0)
                return(0);
        if (foff & PAGE_MASK)
                return(EINVAL);
        if ((prot & maxprot) != prot)
                return(EINVAL);

        /*
         * for non-fixed mappings, round off the suggested address.
         * for fixed mappings, check alignment and zap old mappings.
         */

        if ((flags & MAP_FIXED) == 0) {
                *addr = round_page(*addr);
        } else {
                if (*addr & PAGE_MASK)
                        return(EINVAL);
                uvmflag |= UVM_FLAG_FIXED;
                (void) uvm_unmap(map, *addr, *addr + size);
        }

        /*
         * Try to see if any requested alignment can even be attemped.
         * Make sure we can express the alignment (asking for a >= 4GB
         * alignment on an ILP32 architecure make no sense) and the
         * alignment is at least for a page sized quanitiy.  If the
         * request was for a fixed mapping, make sure supplied address
         * adheres to the request alignment.
         */
        align = (flags & MAP_ALIGNMENT_MASK) >> MAP_ALIGNMENT_SHIFT;
        if (align) {
                if (align >= sizeof(vaddr_t) * NBBY)
                        return(EINVAL);
                align = 1L << align;
                if (align < PAGE_SIZE)
                        return(EINVAL);
                if (align >= vm_map_max(map))
                        return(ENOMEM);
                if (flags & MAP_FIXED) {
                        if ((*addr & (align-1)) != 0)
                                return(EINVAL);
                        align = 0;
                }
        }

        /*
         * check resource limits
         */

        if (!VM_MAP_IS_KERNEL(map) &&
            (((rlim_t)curproc->p_vmspace->vm_map.size + (rlim_t)size) >
            curproc->p_rlimit[RLIMIT_AS].rlim_cur))
                return ENOMEM;

        /*
         * handle anon vs. non-anon mappings.   for non-anon mappings attach
         * to underlying vm object.
         */

        if (flags & MAP_ANON) {
                KASSERT(handle == NULL);
                foff = UVM_UNKNOWN_OFFSET;
                uobj = NULL;
                if ((flags & MAP_SHARED) == 0)
                        /* XXX: defer amap create */
                        uvmflag |= UVM_FLAG_COPYONW;
                else
                        /* shared: create amap now */
                        uvmflag |= UVM_FLAG_OVERLAY;

        } else {
                KASSERT(handle != NULL);
                vp = (struct vnode *)handle;

                /*
                 * Don't allow mmap for EXEC if the file system
                 * is mounted NOEXEC.
                 */
                if ((prot & PROT_EXEC) != 0 &&
                    (vp->v_mount->mnt_flag & MNT_NOEXEC) != 0)
                        return (EACCES);

                if (vp->v_type != VCHR) {
                        error = VOP_MMAP(vp, prot, curlwp->l_cred);
                        if (error) {
                                return error;
                        }
                        vref(vp);
                        uobj = &vp->v_uobj;

                        /*
                         * If the vnode is being mapped with PROT_EXEC,
                         * then mark it as text.
                         */
                        if (prot & PROT_EXEC) {
                                vn_markexec(vp);
                        }
                } else {
                        int i = maxprot;

                        /*
                         * XXX Some devices don't like to be mapped with
                         * XXX PROT_EXEC or PROT_WRITE, but we don't really
                         * XXX have a better way of handling this, right now
                         */
                        do {
                                uobj = udv_attach((void *) &vp->v_rdev,
                                    (flags & MAP_SHARED) ? i :
                                    (i & ~VM_PROT_WRITE), foff, size);
                                i--;
                        } while ((uobj == NULL) && (i > 0));
                        if (uobj == NULL)
                                return EINVAL;
                        advice = UVM_ADV_RANDOM;
                }
                if ((flags & MAP_SHARED) == 0) {
                        uvmflag |= UVM_FLAG_COPYONW;
                }

                /*
                 * Set vnode flags to indicate the new kinds of mapping.
                 * We take the vnode lock in exclusive mode here to serialize
                 * with direct I/O.
                 *
                 * Safe to check for these flag values without a lock, as
                 * long as a reference to the vnode is held.
                 */
                needwritemap = (vp->v_iflag & VI_WRMAP) == 0 &&
                        (flags & MAP_SHARED) != 0 &&
                        (maxprot & VM_PROT_WRITE) != 0;
                if ((vp->v_vflag & VV_MAPPED) == 0 || needwritemap) {
                        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
                        vp->v_vflag |= VV_MAPPED;
                        if (needwritemap) {
                                mutex_enter(&vp->v_interlock);
                                vp->v_iflag |= VI_WRMAP;
                                mutex_exit(&vp->v_interlock);
                        }
                        VOP_UNLOCK(vp, 0);
                }
        }

        uvmflag = UVM_MAPFLAG(prot, maxprot,
                        (flags & MAP_SHARED) ? UVM_INH_SHARE : UVM_INH_COPY,
                        advice, uvmflag);
        error = uvm_map(map, addr, size, uobj, foff, align, uvmflag);
        if (error) {
                if (uobj)
                        uobj->pgops->pgo_detach(uobj);
                return error;
        }

        /*
         * POSIX 1003.1b -- if our address space was configured
         * to lock all future mappings, wire the one we just made.
         *
         * Also handle the MAP_WIRED flag here.
         */

        if (prot == VM_PROT_NONE) {

                /*
                 * No more work to do in this case.
                 */

                return (0);
        }
        if ((flags & MAP_WIRED) != 0 || (map->flags & VM_MAP_WIREFUTURE) != 0) {
                vm_map_lock(map);
                if (atop(size) + uvmexp.wired > uvmexp.wiredmax ||
                    (locklimit != 0 &&
                     size + ptoa(pmap_wired_count(vm_map_pmap(map))) >
                     locklimit)) {
                        vm_map_unlock(map);
                        uvm_unmap(map, *addr, *addr + size);
                        return ENOMEM;
                }

                /*
                 * uvm_map_pageable() always returns the map unlocked.
                 */

                error = uvm_map_pageable(map, *addr, *addr + size,
                                         false, UVM_LK_ENTER);
                if (error) {
                        uvm_unmap(map, *addr, *addr + size);
                        return error;
                }
                return (0);
        }
        return 0;
}

vaddr_t
uvm_default_mapaddr(struct proc *p, vaddr_t base, vsize_t sz)
{

        return VM_DEFAULT_ADDRESS(base, sz);
}