e37e60c379
more appropriate named kernel options for the very distinct send and receive path. "options SOCKET_SEND_COW" enables VM page copy-on-write based sending of data on an outbound socket. NB: The COW based send mechanism is not safe and may result in kernel crashes. "options SOCKET_RECV_PFLIP" enables VM kernel/userspace page flipping for special disposable pages attached as external storage to mbufs. Only the naming of the kernel options is changed and their corresponding #ifdef sections are adjusted. No functionality is added or removed. Discussed with: alc (mechanism and limitations of send side COW)
561 lines
13 KiB
C
561 lines
13 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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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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* 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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* @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_zero.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/limits.h>
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#include <sys/lock.h>
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#include <sys/mman.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/sched.h>
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#include <sys/sysctl.h>
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#include <sys/vnode.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_extern.h>
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#include <vm/vm_page.h>
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#include <vm/vm_map.h>
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#ifdef SOCKET_SEND_COW
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#include <vm/vm_object.h>
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#endif
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SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
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"Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
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static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault);
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#ifdef SOCKET_SEND_COW
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/* Declared in uipc_socket.c */
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extern int so_zero_copy_receive;
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/*
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* Identify the physical page mapped at the given kernel virtual
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* address. Insert this physical page into the given address space at
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* the given virtual address, replacing the physical page, if any,
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* that already exists there.
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*/
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static int
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vm_pgmoveco(vm_map_t mapa, vm_offset_t kaddr, vm_offset_t uaddr)
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{
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vm_map_t map = mapa;
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vm_page_t kern_pg, user_pg;
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vm_object_t uobject;
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vm_map_entry_t entry;
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vm_pindex_t upindex;
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vm_prot_t prot;
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boolean_t wired;
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KASSERT((uaddr & PAGE_MASK) == 0,
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("vm_pgmoveco: uaddr is not page aligned"));
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/*
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* Herein the physical page is validated and dirtied. It is
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* unwired in sf_buf_mext().
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*/
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kern_pg = PHYS_TO_VM_PAGE(vtophys(kaddr));
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kern_pg->valid = VM_PAGE_BITS_ALL;
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KASSERT(kern_pg->queue == PQ_NONE && kern_pg->wire_count == 1,
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("vm_pgmoveco: kern_pg is not correctly wired"));
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if ((vm_map_lookup(&map, uaddr,
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VM_PROT_WRITE, &entry, &uobject,
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&upindex, &prot, &wired)) != KERN_SUCCESS) {
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return(EFAULT);
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}
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VM_OBJECT_LOCK(uobject);
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retry:
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if ((user_pg = vm_page_lookup(uobject, upindex)) != NULL) {
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if (vm_page_sleep_if_busy(user_pg, TRUE, "vm_pgmoveco"))
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goto retry;
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vm_page_lock(user_pg);
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pmap_remove_all(user_pg);
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vm_page_free(user_pg);
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vm_page_unlock(user_pg);
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} else {
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/*
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* Even if a physical page does not exist in the
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* object chain's first object, a physical page from a
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* backing object may be mapped read only.
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*/
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if (uobject->backing_object != NULL)
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pmap_remove(map->pmap, uaddr, uaddr + PAGE_SIZE);
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}
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vm_page_insert(kern_pg, uobject, upindex);
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vm_page_dirty(kern_pg);
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VM_OBJECT_UNLOCK(uobject);
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vm_map_lookup_done(map, entry);
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return(KERN_SUCCESS);
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}
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#endif /* SOCKET_SEND_COW */
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int
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copyin_nofault(const void *udaddr, void *kaddr, size_t len)
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{
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int error, save;
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save = vm_fault_disable_pagefaults();
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error = copyin(udaddr, kaddr, len);
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vm_fault_enable_pagefaults(save);
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return (error);
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}
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int
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copyout_nofault(const void *kaddr, void *udaddr, size_t len)
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{
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int error, save;
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save = vm_fault_disable_pagefaults();
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error = copyout(kaddr, udaddr, len);
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vm_fault_enable_pagefaults(save);
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return (error);
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}
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int
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uiomove(void *cp, int n, struct uio *uio)
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{
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return (uiomove_faultflag(cp, n, uio, 0));
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}
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int
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uiomove_nofault(void *cp, int n, struct uio *uio)
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{
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return (uiomove_faultflag(cp, n, uio, 1));
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}
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static int
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uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault)
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{
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struct thread *td;
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struct iovec *iov;
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size_t cnt;
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int error, newflags, save;
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td = curthread;
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error = 0;
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KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
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("uiomove: mode"));
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KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td,
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("uiomove proc"));
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if (!nofault)
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WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
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"Calling uiomove()");
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/* XXX does it make a sense to set TDP_DEADLKTREAT for UIO_SYSSPACE ? */
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newflags = TDP_DEADLKTREAT;
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if (uio->uio_segflg == UIO_USERSPACE && nofault) {
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/*
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* Fail if a non-spurious page fault occurs.
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*/
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newflags |= TDP_NOFAULTING | TDP_RESETSPUR;
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}
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save = curthread_pflags_set(newflags);
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while (n > 0 && uio->uio_resid) {
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iov = uio->uio_iov;
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cnt = iov->iov_len;
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if (cnt == 0) {
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uio->uio_iov++;
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uio->uio_iovcnt--;
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continue;
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}
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if (cnt > n)
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cnt = n;
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switch (uio->uio_segflg) {
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case UIO_USERSPACE:
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maybe_yield();
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if (uio->uio_rw == UIO_READ)
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error = copyout(cp, iov->iov_base, cnt);
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else
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error = copyin(iov->iov_base, cp, cnt);
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if (error)
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goto out;
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break;
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case UIO_SYSSPACE:
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if (uio->uio_rw == UIO_READ)
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bcopy(cp, iov->iov_base, cnt);
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else
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bcopy(iov->iov_base, cp, cnt);
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break;
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case UIO_NOCOPY:
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break;
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}
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iov->iov_base = (char *)iov->iov_base + cnt;
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iov->iov_len -= cnt;
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uio->uio_resid -= cnt;
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uio->uio_offset += cnt;
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cp = (char *)cp + cnt;
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n -= cnt;
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}
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out:
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curthread_pflags_restore(save);
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return (error);
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}
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/*
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* Wrapper for uiomove() that validates the arguments against a known-good
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* kernel buffer. Currently, uiomove accepts a signed (n) argument, which
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* is almost definitely a bad thing, so we catch that here as well. We
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* return a runtime failure, but it might be desirable to generate a runtime
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* assertion failure instead.
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*/
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int
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uiomove_frombuf(void *buf, int buflen, struct uio *uio)
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{
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size_t offset, n;
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if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
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(offset = uio->uio_offset) != uio->uio_offset)
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return (EINVAL);
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if (buflen <= 0 || offset >= buflen)
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return (0);
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if ((n = buflen - offset) > IOSIZE_MAX)
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return (EINVAL);
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return (uiomove((char *)buf + offset, n, uio));
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}
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#ifdef SOCKET_RECV_PFLIP
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/*
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* Experimental support for zero-copy I/O
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*/
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static int
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userspaceco(void *cp, u_int cnt, struct uio *uio, int disposable)
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{
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struct iovec *iov;
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int error;
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iov = uio->uio_iov;
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if (uio->uio_rw == UIO_READ) {
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if ((so_zero_copy_receive != 0)
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&& ((cnt & PAGE_MASK) == 0)
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&& ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0)
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&& ((uio->uio_offset & PAGE_MASK) == 0)
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&& ((((intptr_t) cp) & PAGE_MASK) == 0)
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&& (disposable != 0)) {
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/* SOCKET: use page-trading */
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/*
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* We only want to call vm_pgmoveco() on
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* disposeable pages, since it gives the
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* kernel page to the userland process.
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*/
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error = vm_pgmoveco(&curproc->p_vmspace->vm_map,
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(vm_offset_t)cp, (vm_offset_t)iov->iov_base);
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/*
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* If we get an error back, attempt
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* to use copyout() instead. The
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* disposable page should be freed
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* automatically if we weren't able to move
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* it into userland.
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*/
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if (error != 0)
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error = copyout(cp, iov->iov_base, cnt);
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} else {
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error = copyout(cp, iov->iov_base, cnt);
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}
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} else {
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error = copyin(iov->iov_base, cp, cnt);
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}
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return (error);
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}
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int
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uiomoveco(void *cp, int n, struct uio *uio, int disposable)
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{
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struct iovec *iov;
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u_int cnt;
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int error;
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KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
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("uiomoveco: mode"));
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KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
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("uiomoveco proc"));
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while (n > 0 && uio->uio_resid) {
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iov = uio->uio_iov;
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cnt = iov->iov_len;
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if (cnt == 0) {
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uio->uio_iov++;
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uio->uio_iovcnt--;
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continue;
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}
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if (cnt > n)
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cnt = n;
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switch (uio->uio_segflg) {
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case UIO_USERSPACE:
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maybe_yield();
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error = userspaceco(cp, cnt, uio, disposable);
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if (error)
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return (error);
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break;
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case UIO_SYSSPACE:
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if (uio->uio_rw == UIO_READ)
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bcopy(cp, iov->iov_base, cnt);
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else
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bcopy(iov->iov_base, cp, cnt);
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break;
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case UIO_NOCOPY:
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break;
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}
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iov->iov_base = (char *)iov->iov_base + cnt;
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iov->iov_len -= cnt;
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uio->uio_resid -= cnt;
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uio->uio_offset += cnt;
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cp = (char *)cp + cnt;
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n -= cnt;
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}
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return (0);
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}
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#endif /* SOCKET_RECV_PFLIP */
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/*
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* Give next character to user as result of read.
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*/
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int
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ureadc(int c, struct uio *uio)
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{
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struct iovec *iov;
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char *iov_base;
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WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
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"Calling ureadc()");
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again:
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if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
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panic("ureadc");
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iov = uio->uio_iov;
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if (iov->iov_len == 0) {
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uio->uio_iovcnt--;
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uio->uio_iov++;
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goto again;
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}
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switch (uio->uio_segflg) {
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case UIO_USERSPACE:
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if (subyte(iov->iov_base, c) < 0)
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return (EFAULT);
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break;
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case UIO_SYSSPACE:
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iov_base = iov->iov_base;
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*iov_base = c;
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iov->iov_base = iov_base;
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break;
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case UIO_NOCOPY:
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break;
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}
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iov->iov_base = (char *)iov->iov_base + 1;
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iov->iov_len--;
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uio->uio_resid--;
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uio->uio_offset++;
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return (0);
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}
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int
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copyinfrom(const void * __restrict src, void * __restrict dst, size_t len,
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int seg)
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{
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int error = 0;
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switch (seg) {
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case UIO_USERSPACE:
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error = copyin(src, dst, len);
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break;
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case UIO_SYSSPACE:
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bcopy(src, dst, len);
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break;
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default:
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panic("copyinfrom: bad seg %d\n", seg);
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}
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return (error);
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}
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|
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int
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copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len,
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size_t * __restrict copied, int seg)
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|
{
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int error = 0;
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switch (seg) {
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|
case UIO_USERSPACE:
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|
error = copyinstr(src, dst, len, copied);
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|
break;
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|
case UIO_SYSSPACE:
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|
error = copystr(src, dst, len, copied);
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break;
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|
default:
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panic("copyinstrfrom: bad seg %d\n", seg);
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}
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return (error);
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}
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int
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copyiniov(const struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error)
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|
{
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|
u_int iovlen;
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*iov = NULL;
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|
if (iovcnt > UIO_MAXIOV)
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return (error);
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iovlen = iovcnt * sizeof (struct iovec);
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*iov = malloc(iovlen, M_IOV, M_WAITOK);
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error = copyin(iovp, *iov, iovlen);
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|
if (error) {
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free(*iov, M_IOV);
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*iov = NULL;
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}
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|
return (error);
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}
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|
|
int
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|
copyinuio(const struct iovec *iovp, u_int iovcnt, struct uio **uiop)
|
|
{
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|
struct iovec *iov;
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|
struct uio *uio;
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|
u_int iovlen;
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|
int error, i;
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*uiop = NULL;
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|
if (iovcnt > UIO_MAXIOV)
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return (EINVAL);
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iovlen = iovcnt * sizeof (struct iovec);
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uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
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iov = (struct iovec *)(uio + 1);
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error = copyin(iovp, iov, iovlen);
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|
if (error) {
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free(uio, M_IOV);
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return (error);
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}
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|
uio->uio_iov = iov;
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|
uio->uio_iovcnt = iovcnt;
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uio->uio_segflg = UIO_USERSPACE;
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uio->uio_offset = -1;
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uio->uio_resid = 0;
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for (i = 0; i < iovcnt; i++) {
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if (iov->iov_len > IOSIZE_MAX - uio->uio_resid) {
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free(uio, M_IOV);
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return (EINVAL);
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}
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uio->uio_resid += iov->iov_len;
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iov++;
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|
}
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*uiop = uio;
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|
return (0);
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}
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struct uio *
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cloneuio(struct uio *uiop)
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|
{
|
|
struct uio *uio;
|
|
int iovlen;
|
|
|
|
iovlen = uiop->uio_iovcnt * sizeof (struct iovec);
|
|
uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
|
|
*uio = *uiop;
|
|
uio->uio_iov = (struct iovec *)(uio + 1);
|
|
bcopy(uiop->uio_iov, uio->uio_iov, iovlen);
|
|
return (uio);
|
|
}
|
|
|
|
/*
|
|
* Map some anonymous memory in user space of size sz, rounded up to the page
|
|
* boundary.
|
|
*/
|
|
int
|
|
copyout_map(struct thread *td, vm_offset_t *addr, size_t sz)
|
|
{
|
|
struct vmspace *vms;
|
|
int error;
|
|
vm_size_t size;
|
|
|
|
vms = td->td_proc->p_vmspace;
|
|
|
|
/*
|
|
* Map somewhere after heap in process memory.
|
|
*/
|
|
PROC_LOCK(td->td_proc);
|
|
*addr = round_page((vm_offset_t)vms->vm_daddr +
|
|
lim_max(td->td_proc, RLIMIT_DATA));
|
|
PROC_UNLOCK(td->td_proc);
|
|
|
|
/* round size up to page boundry */
|
|
size = (vm_size_t)round_page(sz);
|
|
|
|
error = vm_mmap(&vms->vm_map, addr, size, PROT_READ | PROT_WRITE,
|
|
VM_PROT_ALL, MAP_PRIVATE | MAP_ANON, OBJT_DEFAULT, NULL, 0);
|
|
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Unmap memory in user space.
|
|
*/
|
|
int
|
|
copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz)
|
|
{
|
|
vm_map_t map;
|
|
vm_size_t size;
|
|
|
|
if (sz == 0)
|
|
return (0);
|
|
|
|
map = &td->td_proc->p_vmspace->vm_map;
|
|
size = (vm_size_t)round_page(sz);
|
|
|
|
if (vm_map_remove(map, addr, addr + size) != KERN_SUCCESS)
|
|
return (EINVAL);
|
|
|
|
return (0);
|
|
}
|