freebsd-dev/sys/compat/linuxkpi/common/include/linux/page.h
Hans Petter Selasky 1ea4c85781 Implement proper support for memory map operations in the LinuxKPI,
like open, close and fault using the character device pager.

Some notes about the implementation:

1) Linux drivers set the vm_ops and vm_private_data fields during a
mmap() call to indicate that the driver wants to use the LinuxKPI VM
operations. Else these operations are not used.

2) The vm_private_data pointer is associated with a VM area structure
and inserted into an internal LinuxKPI list. If the vm_private_data
pointer already exists, the existing VM area structure is used instead
of the allocated one which gets freed.

3) The LinuxKPI's vm_private_data pointer is used as the callback
handle for the FreeBSD VM object. The VM subsystem in FreeBSD has a
similar list to identify equal handles and will only call the
character device pager's close function once.

4) All LinuxKPI VM operations are serialized through the mmap_sem
sempaphore, which is per procedure, which prevents simultaneous access
to the shared VM area structure when receiving page faults.

Obtained from:		kmacy @
MFC after:		1 week
Sponsored by:		Mellanox Technologies
2017-04-06 09:34:54 +00:00

96 lines
3.2 KiB
C

/*-
* Copyright (c) 2010 Isilon Systems, Inc.
* Copyright (c) 2010 iX Systems, Inc.
* Copyright (c) 2010 Panasas, Inc.
* Copyright (c) 2013-2016 Mellanox Technologies, Ltd.
* All rights reserved.
*
* 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 unmodified, 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* $FreeBSD$
*/
#ifndef _LINUX_PAGE_H_
#define _LINUX_PAGE_H_
#include <linux/types.h>
#include <sys/param.h>
#include <machine/atomic.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/pmap.h>
typedef unsigned long pte_t;
typedef unsigned long pmd_t;
typedef unsigned long pgd_t;
typedef unsigned long pgprot_t;
#define page vm_page
#define LINUXKPI_PROT_VALID (1 << 4)
#define LINUXKPI_CACHE_MODE_SHIFT 3
static inline pgprot_t
cachemode2protval(vm_memattr_t attr)
{
return ((attr | LINUXKPI_PROT_VALID) << LINUXKPI_CACHE_MODE_SHIFT);
}
static inline vm_memattr_t
pgprot2cachemode(pgprot_t prot)
{
int val;
val = prot >> LINUXKPI_CACHE_MODE_SHIFT;
if (val & LINUXKPI_PROT_VALID)
return (val & ~LINUXKPI_PROT_VALID);
else
return (VM_MEMATTR_DEFAULT);
}
#define virt_to_page(x) PHYS_TO_VM_PAGE(vtophys((x)))
#define page_to_pfn(pp) (VM_PAGE_TO_PHYS((pp)) >> PAGE_SHIFT)
#define pfn_to_page(pfn) (PHYS_TO_VM_PAGE((pfn) << PAGE_SHIFT))
#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
#define clear_page(page) memset((page), 0, PAGE_SIZE)
#define pgprot_noncached(prot) ((pgprot_t)VM_MEMATTR_UNCACHEABLE)
#define pgprot_writecombine(prot) ((pgprot_t)VM_MEMATTR_WRITE_COMBINING)
#undef PAGE_MASK
#define PAGE_MASK (~(PAGE_SIZE-1))
/*
* Modifying PAGE_MASK in the above way breaks trunc_page, round_page,
* and btoc macros. Therefore, redefine them in a way that makes sense
* so the LinuxKPI consumers don't get totally broken behavior.
*/
#undef btoc
#define btoc(x) (((vm_offset_t)(x) + PAGE_SIZE - 1) >> PAGE_SHIFT)
#undef round_page
#define round_page(x) ((((uintptr_t)(x)) + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1))
#undef trunc_page
#define trunc_page(x) ((uintptr_t)(x) & ~(PAGE_SIZE - 1))
#endif /* _LINUX_PAGE_H_ */