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1288 jermar 1 
/*
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 * Copyright (c) 2006 Jakub Jermar
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 * All rights reserved.
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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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 *
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 * - 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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 * - 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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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/** @addtogroup generic
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 * @{
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 */
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/**
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 * @file
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 * @brief   Copying between kernel and userspace.
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 *
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 * This file contains sanitized functions for copying data
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 * between kernel and userspace.
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 */
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#include <syscall/copy.h>
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#include <proc/thread.h>
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#include <mm/as.h>
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#include <macros.h>
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#include <arch.h>
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#include <errno.h>
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/** Copy data from userspace to kernel.
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 *
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 * Provisions are made to return value even after page fault.
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 *
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 * This function can be called only from syscall.
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 *
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 * @param dst Destination kernel address.
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 * @param uspace_src Source userspace address.
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 * @param size Size of the data to be copied.
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 *
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 * @return 0 on success or error code from @ref errno.h.
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 */
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int copy_from_uspace(void *dst, const void *uspace_src, size_t size)
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{
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    ipl_t ipl;
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    int rc;
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    ASSERT(THREAD);
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    ASSERT(!THREAD->in_copy_from_uspace);
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    if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
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        if (overlaps((uintptr_t) uspace_src, size,
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            KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START)) {
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            /*
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             * The userspace source block conflicts with kernel address space.
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             */
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            return EPERM;
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        }
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    }
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    ipl = interrupts_disable();
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    THREAD->in_copy_from_uspace = true;
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    rc = memcpy_from_uspace(dst, uspace_src, size);
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    THREAD->in_copy_from_uspace = false;
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    interrupts_restore(ipl);
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    return !rc ? EPERM : 0;
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}
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/** Copy data from kernel to userspace.
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 *
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 * Provisions are made to return value even after page fault.
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 *
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 * This function can be called only from syscall.
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 *
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 * @param uspace_dst Destination userspace address.
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 * @param src Source kernel address.
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 * @param size Size of the data to be copied.
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 *
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 * @return 0 on success or error code from @ref errno.h.
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 */
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int copy_to_uspace(void *uspace_dst, const void *src, size_t size)
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{
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    ipl_t ipl;
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    int rc;
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    ASSERT(THREAD);
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    ASSERT(!THREAD->in_copy_to_uspace);
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    if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
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        if (overlaps((uintptr_t) uspace_dst, size,
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            KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START)) {
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            /*
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             * The userspace destination block conflicts with kernel address space.
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             */
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            return EPERM;
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        }
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    }
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    ipl = interrupts_disable();
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    THREAD->in_copy_to_uspace = true;
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    rc = memcpy_to_uspace(uspace_dst, src, size);
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    THREAD->in_copy_to_uspace = false;
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    interrupts_restore(ipl);
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    return !rc ? EPERM : 0;
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}
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/** @}
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 */