/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2004 Alan L. Cox <alc@cs.rice.edu>
 * Copyright (c) 1982, 1986, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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.
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <sys/sf_buf.h>

#include <vm/vm.h>
#include <vm/vm_page.h>

#include <machine/vmparam.h>

/*
 * Implement uiomove(9) from physical memory using sf_bufs to
 * avoid the creation and destruction of ephemeral mappings.
 */
int
uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
{
        struct thread *td = curthread;
        struct iovec *iov;
        void *cp;
        vm_offset_t page_offset;
        size_t cnt;
        int error = 0;
        int save = 0;
        struct sf_buf *sf;

        KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
            ("uiomove_fromphys: mode"));
        KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
            ("uiomove_fromphys proc"));
        KASSERT(uio->uio_resid >= 0,
            ("%s: uio %p resid underflow", __func__, uio));

        save = td->td_pflags & TDP_DEADLKTREAT;
        td->td_pflags |= TDP_DEADLKTREAT;
        while (n > 0 && uio->uio_resid) {
                KASSERT(uio->uio_iovcnt > 0,
                    ("%s: uio %p iovcnt underflow", __func__, uio));

                iov = uio->uio_iov;
                cnt = iov->iov_len;
                if (cnt == 0) {
                        uio->uio_iov++;
                        uio->uio_iovcnt--;
                        continue;
                }
                if (cnt > n)
                        cnt = n;
                page_offset = offset & PAGE_MASK;
                cnt = min(cnt, PAGE_SIZE - page_offset);
                sf = sf_buf_alloc(ma[offset >> PAGE_SHIFT], 0);
                cp = (char*)sf_buf_kva(sf) + page_offset;
                switch (uio->uio_segflg) {
                case UIO_USERSPACE:
                        maybe_yield();
                        switch (uio->uio_rw) {
                        case UIO_READ:
                                error = copyout(cp, iov->iov_base, cnt);
                                break;
                        case UIO_WRITE:
                                error = copyin(iov->iov_base, cp, cnt);
                                break;
                        }
                        if (error) {
                                sf_buf_free(sf);
                                goto out;
                        }
                        break;
                case UIO_SYSSPACE:
                        switch (uio->uio_rw) {
                        case UIO_READ:
                                bcopy(cp, iov->iov_base, cnt);
                                break;
                        case UIO_WRITE:
                                bcopy(iov->iov_base, cp, cnt);
                                break;
                        }
                        break;
                case UIO_NOCOPY:
                        break;
                }
                sf_buf_free(sf);
                iov->iov_base = (char *)iov->iov_base + cnt;
                iov->iov_len -= cnt;
                uio->uio_resid -= cnt;
                uio->uio_offset += cnt;
                offset += cnt;
                n -= cnt;
        }
out:
        if (save == 0)
                td->td_pflags &= ~TDP_DEADLKTREAT;
        return (error);
}