uvm_mmap.c

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/*	$NetBSD: uvm_mmap.c,v 1.46 2000/11/27 08:40:04 chs 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/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>

#include <miscfs/specfs/specdev.h>

#include <sys/syscallargs.h>

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

#ifdef OSKIT
#include "oskit_uvm_internal.h"
#endif

#ifndef OSKIT
/*
 * unimplemented VM system calls:
 */

/*
 * sys_sbrk: sbrk system call.
 */

/* ARGSUSED */
int
sys_sbrk(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
#if 0
	struct sys_sbrk_args /* {
		syscallarg(intptr_t) incr;
	} */ *uap = v;
#endif

	return (ENOSYS);
}

/*
 * sys_sstk: sstk system call.
 */

/* ARGSUSED */
int
sys_sstk(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
#if 0
	struct sys_sstk_args /* {
		syscallarg(int) incr;
	} */ *uap = v;
#endif

	return (ENOSYS);
}

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

/* ARGSUSED */
int
sys_mincore(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_mincore_args /* {
		syscallarg(void *) addr;
		syscallarg(size_t) len;
		syscallarg(char *) vec;
	} */ *uap = v;
	vm_page_t m;
	char *vec, pgi;
	struct uvm_object *uobj;
	struct vm_amap *amap;
	struct vm_anon *anon;
	vm_map_entry_t entry;
	vaddr_t start, end, lim;
	vm_map_t 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);

	npgs = len >> PAGE_SHIFT;

	if (uvm_useracc(vec, npgs, B_WRITE) == FALSE)
		return (EFAULT);

	/*
	 * Lock down vec, so our returned status isn't outdated by
	 * storing the status byte for a page.
	 */
	uvm_vslock(p, vec, npgs, VM_PROT_WRITE);

	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) {
#ifdef DIAGNOSTIC
		if (UVM_ET_ISSUBMAP(entry))
			panic("mincore: user map has submap");
		if (start < entry->start)
			panic("mincore: hole");
#endif
		/* 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)) {
#ifdef DIAGNOSTIC
			if (UVM_OBJ_IS_KERN_OBJECT(entry->object.uvm_obj))
				panic("mincore: user map has kernel object");
#endif
			if (entry->object.uvm_obj->pgops->pgo_releasepg
			    == NULL) {
				for (/* nothing */; start < lim;
				     start += PAGE_SIZE, vec++)
					subyte(vec, 1);
				continue;
			}
		}

		amap = entry->aref.ar_amap;	/* top layer */
		uobj = entry->object.uvm_obj;	/* bottom layer */

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

		for (/* nothing */; start < lim; start += PAGE_SIZE, vec++) {
			pgi = 0;
			if (amap != NULL) {
				/* Check the top layer first. */
				anon = amap_lookup(&entry->aref,
				    start - entry->start);
				/* Don't need to lock anon here. */
				if (anon != NULL && anon->u.an_page != NULL) {
					/*
					 * Anon has the page for this entry
					 * offset.
					 */
					pgi = 1;
				}
			}

			if (uobj != NULL && pgi == 0) {
				/* Check the bottom layer. */
				m = uvm_pagelookup(uobj,
				    entry->offset + (start - entry->start));
				if (m != NULL) {
					/*
					 * Object has the page for this entry
					 * offset.
					 */
					pgi = 1;
				}
			}

			(void) subyte(vec, pgi);
		}

		if (uobj != NULL)
			simple_unlock(&uobj->vmobjlock);
		if (amap != NULL)
			amap_unlock(amap);
	}

 out:
	vm_map_unlock_read(map);
	uvm_vsunlock(p, SCARG(uap, vec), npgs);
	return (error);
}
#endif /*OSKIT*/

/*
 * sys_mmap: mmap system call.
 *
 * => file offest 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(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_mmap_args /* {
		syscallarg(caddr_t) addr;
		syscallarg(size_t) len;
		syscallarg(int) prot;
		syscallarg(int) flags;
		syscallarg(int) fd;
		syscallarg(long) pad;
		syscallarg(off_t) pos;
	} */ *uap = v;
	vaddr_t addr;
#ifndef OSKIT
	struct vattr va;
#endif
	off_t pos;
	vsize_t size, pageoff;
	vm_prot_t prot, maxprot;
#ifdef OSKIT
	int flags;
#else
	int flags, fd;
#endif
	vaddr_t vm_min_address = VM_MIN_ADDRESS;
#ifndef OSKIT
	struct filedesc *fdp = p->p_fd;
	struct file *fp;
	struct vnode *vp;
#else
	struct file xfp;
	struct file *fp = &xfp;
	struct vnode xvp;
	struct vnode *vp = &xvp;
#endif
	caddr_t handle;
	int error;
#ifdef OSKIT
	oskit_iunknown_t *iunknown;
	vp->v_type = VREG;
	fp->f_flag = FREAD|FWRITE;
#endif

	/*
	 * 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);
#ifdef OSKIT
	iunknown = (oskit_iunknown_t*)SCARG(uap, fd);
#else
	fd = SCARG(uap, fd);
#endif
	pos = SCARG(uap, pos);

	/*
	 * 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 */
	if ((ssize_t) size < 0)
		return (EINVAL);			/* don't allow wrap */

	/*
	 * 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);

		if (VM_MAXUSER_ADDRESS > 0 &&
		    (addr + size) > VM_MAXUSER_ADDRESS)
			return (EINVAL);
		if (vm_min_address > 0 && addr < vm_min_address)
			return (EINVAL);
		if (addr > addr + size)
			return (EINVAL);		/* no wrapping! */

	} else {

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

		if (addr < round_page((vaddr_t)p->p_vmspace->vm_daddr +
		    MAXDSIZ))
			addr = round_page((vaddr_t)p->p_vmspace->vm_daddr +
			    MAXDSIZ);
	}

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

	if ((flags & MAP_ANON) == 0) {

#ifndef OSKIT
		if (fd < 0 || fd >= fdp->fd_nfiles)
			return(EBADF);		/* failed range check? */
		fp = fdp->fd_ofiles[fd];	/* convert to file pointer */
		if (fp == NULL)
			return(EBADF);

		if (fp->f_type != DTYPE_VNODE)
			return (ENODEV);		/* only mmap vnodes! */
		vp = (struct vnode *)fp->f_data;	/* convert to vnode */

		if (vp->v_type != VREG && vp->v_type != VCHR &&
		    vp->v_type != VBLK)
			return (ENODEV);  /* only REG/CHR/BLK support mmap */

		if (vp->v_type == VREG && (pos + size) < pos)
			return (EOVERFLOW);		/* no offset wrapping */

		/* special case: catch SunOS style /dev/zero */
		if (vp->v_type == VCHR && iszerodev(vp->v_rdev)) {
			flags |= MAP_ANON;
			goto is_anon;
		}
#endif /*OSKIT*/
		/*
		 * 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 comm %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) {
#if defined(DIAGNOSTIC)
			printf("WARNING: converted MAP_PRIVATE device mapping "
			    "to MAP_SHARED (pid %d comm %s)\n", p->p_pid,
			    p->p_comm);
#endif
			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)
			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) {
#ifdef OSKIT
				maxprot |= VM_PROT_WRITE;
#else
				if ((error =
				    VOP_GETATTR(vp, &va, p->p_ucred, p)))
					return (error);
				if ((va.va_flags & (IMMUTABLE|APPEND)) == 0)
					maxprot |= VM_PROT_WRITE;
				else if (prot & PROT_WRITE)
					return (EPERM);
#endif
			}
			else if (prot & PROT_WRITE)
				return (EACCES);
		} else {
			/* MAP_PRIVATE mappings can always write to */
			maxprot |= VM_PROT_WRITE;
		}

#ifdef OSKIT
		handle = (caddr_t)iunknown;
#else
		/*
		 * set handle to vnode
		 */

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

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

	/*
	 * XXX (in)sanity check.  We don't do proper datasize checking
	 * XXX for anonymous (or private writable) mmap().  However,
	 * XXX know that if we're trying to allocate more than the amount
	 * XXX remaining under our current data size limit, _that_ should
	 * XXX be disallowed.
	 */
	if ((flags & MAP_ANON) != 0 ||
	    ((flags & MAP_PRIVATE) != 0 && (prot & PROT_WRITE) != 0)) {
		if (size >
		    (p->p_rlimit[RLIMIT_DATA].rlim_cur - ctob(p->p_vmspace->vm_dsize))) {
			return (ENOMEM);
		}
	}

	/*
	 * 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);

	return (error);
}


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

int
sys___msync13(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys___msync13_args /* {
		syscallarg(caddr_t) addr;
		syscallarg(size_t) len;
		syscallarg(int) flags;
	} */ *uap = v;
	vaddr_t addr;
	vsize_t size, pageoff;
	vm_map_t map;
	int 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);

	/* disallow wrap-around. */
	if (addr + size < addr)
		return (EINVAL);

	/*
	 * 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) {
		vm_map_entry_t 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;
	else
		uvmflags |= PGO_SYNCIO;	 /* XXXCDC: force sync for now! */

	/*
	 * doit!
	 */
	rv = uvm_map_clean(map, addr, addr+size, uvmflags);

	/*
	 * and return... 
	 */
	switch (rv) {
	case KERN_SUCCESS:
		return(0);
	case KERN_INVALID_ADDRESS:
		return (ENOMEM);
	case KERN_FAILURE:
		return (EIO);