freebsd-dev/sys/compat/linuxkpi/common/include/linux/uaccess.h
Hans Petter Selasky 0a2f4606bb Add comment describing the use of pagefault_disable() and
pagefault_enable() in the LinuxKPI.

Suggested by:  		rpokala@
MFC after:		1 week
Sponsored by:		Mellanox Technologies
2017-03-17 08:02:46 +00:00

92 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.
* Copyright (c) 2015 François Tigeot
* 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_UACCESS_H_
#define _LINUX_UACCESS_H_
#include <sys/param.h>
#include <sys/lock.h>
#include <sys/proc.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <linux/compiler.h>
#define VERIFY_READ VM_PROT_READ
#define VERIFY_WRITE VM_PROT_WRITE
#define __get_user(_x, _p) ({ \
int __err; \
__typeof(*(_p)) __x; \
__err = linux_copyin((_p), &(__x), sizeof(*(_p))); \
(_x) = __x; \
__err; \
})
#define __put_user(_x, _p) ({ \
__typeof(*(_p)) __x = (_x); \
linux_copyout(&(__x), (_p), sizeof(*(_p))); \
})
#define get_user(_x, _p) linux_copyin((_p), &(_x), sizeof(*(_p)))
#define put_user(_x, _p) linux_copyout(&(_x), (_p), sizeof(*(_p)))
#define clear_user(...) linux_clear_user(__VA_ARGS__)
#define access_ok(...) linux_access_ok(__VA_ARGS__)
extern int linux_copyin(const void *uaddr, void *kaddr, size_t len);
extern int linux_copyout(const void *kaddr, void *uaddr, size_t len);
extern size_t linux_clear_user(void *uaddr, size_t len);
extern int linux_access_ok(int rw, const void *uaddr, size_t len);
/*
* NOTE: Each pagefault_disable() call must have a corresponding
* pagefault_enable() call in the same scope. The former creates a new
* block and defines a temporary variable, and the latter uses the
* temporary variable and closes the block. Failure to balance the
* calls will result in a compile-time error.
*/
#define pagefault_disable(void) do { \
int __saved_pflags = \
vm_fault_disable_pagefaults()
#define pagefault_enable(void) \
vm_fault_enable_pagefaults(__saved_pflags); \
} while (0)
static inline bool
pagefault_disabled(void)
{
return ((curthread->td_pflags & TDP_NOFAULTING) != 0);
}
#endif /* _LINUX_UACCESS_H_ */