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/*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* File: scsi_user_dma.c
* Author: Alessandro Forin, Carnegie Mellon University
* Date: 4/91
*
* Mach 2.5 compat file, to handle case of DMA to user space
* [e.g. fsck and other raw device accesses]
*/
#ifdef MACH_KERNEL
/* We do not need this in 3.0 */
#else /*MACH_KERNEL*/
#include <mach/std_types.h>
#include <scsi/adapters/scsi_user_dma.h>
#include <kern/assert.h>
#include <vm/vm_kern.h>
#include <mach/vm_param.h> /* round_page() */
/* bp -> pmap */
#include <sys/buf.h>
#include <sys/proc.h>
/*
* Initialization, called once per device
*/
fdma_init(fdma, size)
fdma_t fdma;
vm_size_t size;
{
vm_offset_t addr;
size = round_page(size);
addr = kmem_alloc_pageable(kernel_map, size);
if (addr == 0) panic("fdma_init");
fdma->kernel_virtual = addr;
fdma->max_data = size;
fdma->user_virtual = -1;
}
/*
* Remap a buffer from user space to kernel space.
* Note that physio() has already validated
* and wired the user's address range.
*/
fdma_map(fdma, bp)
fdma_t fdma;
struct buf *bp;
{
pmap_t pmap;
vm_offset_t user_addr;
vm_size_t size;
vm_offset_t kernel_addr;
vm_offset_t off;
vm_prot_t prot;
/*
* If this is not to user space, or no data xfer is
* involved, no need to do anything.
*/
user_addr = (vm_offset_t)bp->b_un.b_addr;
if (!(bp->b_flags & B_PHYS) || (user_addr == 0)) {
fdma->user_virtual = -1;
return;
}
/*
* We are going to clobber the buffer pointer, so
* remember what it was to restore it later.
*/
fdma->user_virtual = user_addr;
/*
* Account for initial offset into phys page
*/
off = user_addr - trunc_page(user_addr);
/*
* Check xfer size makes sense, note how many pages we'll remap
*/
size = bp->b_bcount + off;
assert((size <= fdma->max_data));
fdma->xfer_size_rnd = round_page(size);
pmap = bp->b_proc->task->map->pmap;
/*
* Use minimal protection possible
*/
prot = VM_PROT_READ;
if (bp->b_flags & B_READ)
prot |= VM_PROT_WRITE;
/*
* Loop through all phys pages, taking them from the
* user pmap (they are wired) and inserting them into
* the kernel pmap.
*/
user_addr -= off;
kernel_addr = fdma->kernel_virtual;
bp->b_un.b_addr = (char *)kernel_addr + off;
for (size = fdma->xfer_size_rnd; size; size -= PAGE_SIZE) {
register vm_offset_t phys;
phys = pmap_extract(pmap, user_addr);
pmap_enter(kernel_pmap, kernel_addr, phys, prot, TRUE);
user_addr += PAGE_SIZE;
kernel_addr += PAGE_SIZE;
}
}
/*
* Called at end of xfer, to restore the buffer
*/
fdma_unmap(fdma, bp)
fdma_t fdma;
struct buf *bp;
{
register vm_offset_t end_addr;
/*
* Check we actually did remap it
*/
if (fdma->user_virtual == -1)
return;
/*
* Restore the buffer
*/
bp->b_un.b_addr = (char *)fdma->user_virtual;
fdma->user_virtual = -1;
/*
* Eliminate the mapping, pmap module might mess up
* the pv list otherwise. Some might actually tolerate it.
*/
end_addr = fdma->kernel_virtual + fdma->xfer_size_rnd;
pmap_remove(kernel_pmap, fdma->kernel_virtual, end_addr);
}
#endif /*MACH_KERNEL*/
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