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userfaultfd: uAPI

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Defines the uAPI of the userfaultfd, notably the ioctl numbers and protocol.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Cc: zhang.zhanghailiang@huawei.com
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrea Arcangeli 2015-09-04 15:46:04 -07:00 committed by Linus Torvalds
parent 51360155ec
commit 1038628d80
3 changed files with 85 additions and 0 deletions
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1
Documentation/ioctl/ioctl-number.txt
View file

@ -303,6 +303,7 @@ Code Seq#(hex) Include File Comments
0xA3 80-8F Port ACL in development:
<mailto:tlewis@mindspring.com>
0xA3 90-9F linux/dtlk.h
0xAA 00-3F linux/uapi/linux/userfaultfd.h
0xAB 00-1F linux/nbd.h
0xAC 00-1F linux/raw.h
0xAD 00 Netfilter device in development:

1
include/uapi/linux/Kbuild
View file

@ -456,3 +456,4 @@ header-y += xfrm.h
header-y += xilinx-v4l2-controls.h
header-y += zorro.h
header-y += zorro_ids.h
header-y += userfaultfd.h

83
include/uapi/linux/userfaultfd.h Normal file
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@ -0,0 +1,83 @@
/*
* include/linux/userfaultfd.h
*
* Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org>
* Copyright (C) 2015 Red Hat, Inc.
*
*/
#ifndef _LINUX_USERFAULTFD_H
#define _LINUX_USERFAULTFD_H
#include <linux/types.h>
#define UFFD_API ((__u64)0xAA)
/* FIXME: add "|UFFD_BIT_WP" to UFFD_API_BITS after implementing it */
#define UFFD_API_BITS (UFFD_BIT_WRITE)
#define UFFD_API_IOCTLS \
((__u64)1 << _UFFDIO_REGISTER | \
(__u64)1 << _UFFDIO_UNREGISTER | \
(__u64)1 << _UFFDIO_API)
#define UFFD_API_RANGE_IOCTLS \
((__u64)1 << _UFFDIO_WAKE)
/*
* Valid ioctl command number range with this API is from 0x00 to
* 0x3F. UFFDIO_API is the fixed number, everything else can be
* changed by implementing a different UFFD_API. If sticking to the
* same UFFD_API more ioctl can be added and userland will be aware of
* which ioctl the running kernel implements through the ioctl command
* bitmask written by the UFFDIO_API.
*/
#define _UFFDIO_REGISTER (0x00)
#define _UFFDIO_UNREGISTER (0x01)
#define _UFFDIO_WAKE (0x02)
#define _UFFDIO_API (0x3F)
/* userfaultfd ioctl ids */
#define UFFDIO 0xAA
#define UFFDIO_API _IOWR(UFFDIO, _UFFDIO_API, \
struct uffdio_api)
#define UFFDIO_REGISTER _IOWR(UFFDIO, _UFFDIO_REGISTER, \
struct uffdio_register)
#define UFFDIO_UNREGISTER _IOR(UFFDIO, _UFFDIO_UNREGISTER, \
struct uffdio_range)
#define UFFDIO_WAKE _IOR(UFFDIO, _UFFDIO_WAKE, \
struct uffdio_range)
/*
* Valid bits below PAGE_SHIFT in the userfault address read through
* the read() syscall.
*/
#define UFFD_BIT_WRITE (1<<0) /* this was a write fault, MISSING or WP */
#define UFFD_BIT_WP (1<<1) /* handle_userfault() reason VM_UFFD_WP */
#define UFFD_BITS 2 /* two above bits used for UFFD_BIT_* mask */
struct uffdio_api {
/* userland asks for an API number */
__u64 api;
/* kernel answers below with the available features for the API */
__u64 bits;
__u64 ioctls;
};
struct uffdio_range {
__u64 start;
__u64 len;
};
struct uffdio_register {
struct uffdio_range range;
#define UFFDIO_REGISTER_MODE_MISSING ((__u64)1<<0)
#define UFFDIO_REGISTER_MODE_WP ((__u64)1<<1)
__u64 mode;
/*
* kernel answers which ioctl commands are available for the
* range, keep at the end as the last 8 bytes aren't read.
*/
__u64 ioctls;
};
#endif /* _LINUX_USERFAULTFD_H */