[linux-2.6-block.git] / include / uapi / linux / userfaultfd.h

/*
 *  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>

#include <linux/compiler.h>

#define UFFD_API ((__u64)0xAA)
/*
 * After implementing the respective features it will become:
 * #define UFFD_API_FEATURES (UFFD_FEATURE_PAGEFAULT_FLAG_WP | \
 *			      UFFD_FEATURE_EVENT_FORK)
 */
#define UFFD_API_FEATURES (0)
#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 |		\
	 (__u64)1 << _UFFDIO_COPY |		\
	 (__u64)1 << _UFFDIO_ZEROPAGE)

/*
 * 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_COPY			(0x03)
#define _UFFDIO_ZEROPAGE		(0x04)
#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)
#define UFFDIO_COPY		_IOWR(UFFDIO, _UFFDIO_COPY,	\
				      struct uffdio_copy)
#define UFFDIO_ZEROPAGE		_IOWR(UFFDIO, _UFFDIO_ZEROPAGE,	\
				      struct uffdio_zeropage)

/* read() structure */
struct uffd_msg {
	__u8	event;

	__u8	reserved1;
	__u16	reserved2;
	__u32	reserved3;

	union {
		struct {
			__u64	flags;
			__u64	address;
		} pagefault;

		struct {
			/* unused reserved fields */
			__u64	reserved1;
			__u64	reserved2;
			__u64	reserved3;
		} reserved;
	} arg;
} __packed;

/*
 * Start at 0x12 and not at 0 to be more strict against bugs.
 */
#define UFFD_EVENT_PAGEFAULT	0x12
#if 0 /* not available yet */
#define UFFD_EVENT_FORK		0x13
#endif

/* flags for UFFD_EVENT_PAGEFAULT */
#define UFFD_PAGEFAULT_FLAG_WRITE	(1<<0)	/* If this was a write fault */
#define UFFD_PAGEFAULT_FLAG_WP		(1<<1)	/* If reason is VM_UFFD_WP */

struct uffdio_api {
	/* userland asks for an API number and the features to enable */
	__u64 api;
	/*
	 * Kernel answers below with the all available features for
	 * the API, this notifies userland of which events and/or
	 * which flags for each event are enabled in the current
	 * kernel.
	 *
	 * Note: UFFD_EVENT_PAGEFAULT and UFFD_PAGEFAULT_FLAG_WRITE
	 * are to be considered implicitly always enabled in all kernels as
	 * long as the uffdio_api.api requested matches UFFD_API.
	 */
#if 0 /* not available yet */
#define UFFD_FEATURE_PAGEFAULT_FLAG_WP		(1<<0)
#define UFFD_FEATURE_EVENT_FORK			(1<<1)
#endif
	__u64 features;

	__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;
};

struct uffdio_copy {
	__u64 dst;
	__u64 src;
	__u64 len;
	/*
	 * There will be a wrprotection flag later that allows to map
	 * pages wrprotected on the fly. And such a flag will be
	 * available if the wrprotection ioctl are implemented for the
	 * range according to the uffdio_register.ioctls.
	 */
#define UFFDIO_COPY_MODE_DONTWAKE		((__u64)1<<0)
	__u64 mode;

	/*
	 * "copy" is written by the ioctl and must be at the end: the
	 * copy_from_user will not read the last 8 bytes.
	 */
	__s64 copy;
};

struct uffdio_zeropage {
	struct uffdio_range range;
#define UFFDIO_ZEROPAGE_MODE_DONTWAKE		((__u64)1<<0)
	__u64 mode;

	/*
	 * "zeropage" is written by the ioctl and must be at the end:
	 * the copy_from_user will not read the last 8 bytes.
	 */
	__s64 zeropage;
};

#endif /* _LINUX_USERFAULTFD_H */
Commit	Line	Data
1038628d AA	1	/*
	2	* include/linux/userfaultfd.h
	3	*
	4	* Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org>
	5	* Copyright (C) 2015 Red Hat, Inc.
	6	*
	7	*/
	8
	9	#ifndef _LINUX_USERFAULTFD_H
	10	#define _LINUX_USERFAULTFD_H
	11
	12	#include <linux/types.h>
	13
a9b85f94 AA	14	#include <linux/compiler.h>
a9b85f94 AA	15
1038628d	16	#define UFFD_API ((__u64)0xAA)
a9b85f94 AA	17	/*
	18	* After implementing the respective features it will become:
	19	* #define UFFD_API_FEATURES (UFFD_FEATURE_PAGEFAULT_FLAG_WP \| \
	20	* UFFD_FEATURE_EVENT_FORK)
	21	*/
	22	#define UFFD_API_FEATURES (0)
1038628d AA	23	#define UFFD_API_IOCTLS \
	24	((__u64)1 << _UFFDIO_REGISTER \| \
	25	(__u64)1 << _UFFDIO_UNREGISTER \| \
	26	(__u64)1 << _UFFDIO_API)
	27	#define UFFD_API_RANGE_IOCTLS \
1f1c6f07 AA	28	((__u64)1 << _UFFDIO_WAKE \| \
	29	(__u64)1 << _UFFDIO_COPY \| \
	30	(__u64)1 << _UFFDIO_ZEROPAGE)
1038628d AA	31
	32	/*
	33	* Valid ioctl command number range with this API is from 0x00 to
	34	* 0x3F. UFFDIO_API is the fixed number, everything else can be
	35	* changed by implementing a different UFFD_API. If sticking to the
	36	* same UFFD_API more ioctl can be added and userland will be aware of
	37	* which ioctl the running kernel implements through the ioctl command
	38	* bitmask written by the UFFDIO_API.
	39	*/
	40	#define _UFFDIO_REGISTER (0x00)
	41	#define _UFFDIO_UNREGISTER (0x01)
	42	#define _UFFDIO_WAKE (0x02)
1f1c6f07 AA	43	#define _UFFDIO_COPY (0x03)
1f1c6f07 AA	44	#define _UFFDIO_ZEROPAGE (0x04)
1038628d AA	45	#define _UFFDIO_API (0x3F)
	46
	47	/* userfaultfd ioctl ids */
	48	#define UFFDIO 0xAA
	49	#define UFFDIO_API _IOWR(UFFDIO, _UFFDIO_API, \
	50	struct uffdio_api)
	51	#define UFFDIO_REGISTER _IOWR(UFFDIO, _UFFDIO_REGISTER, \
	52	struct uffdio_register)
	53	#define UFFDIO_UNREGISTER _IOR(UFFDIO, _UFFDIO_UNREGISTER, \
	54	struct uffdio_range)
	55	#define UFFDIO_WAKE _IOR(UFFDIO, _UFFDIO_WAKE, \
	56	struct uffdio_range)
1f1c6f07 AA	57	#define UFFDIO_COPY _IOWR(UFFDIO, _UFFDIO_COPY, \
	58	struct uffdio_copy)
	59	#define UFFDIO_ZEROPAGE _IOWR(UFFDIO, _UFFDIO_ZEROPAGE, \
	60	struct uffdio_zeropage)
1038628d	61
a9b85f94 AA	62	/* read() structure */
	63	struct uffd_msg {
	64	__u8 event;
	65
	66	__u8 reserved1;
	67	__u16 reserved2;
	68	__u32 reserved3;
	69
	70	union {
	71	struct {
	72	__u64 flags;
	73	__u64 address;
	74	} pagefault;
	75
	76	struct {
	77	/* unused reserved fields */
	78	__u64 reserved1;
	79	__u64 reserved2;
	80	__u64 reserved3;
	81	} reserved;
	82	} arg;
	83	} __packed;
1038628d	84
3f602d27	85	/*
a9b85f94	86	* Start at 0x12 and not at 0 to be more strict against bugs.
3f602d27	87	*/
a9b85f94 AA	88	#define UFFD_EVENT_PAGEFAULT 0x12
	89	#if 0 /* not available yet */
	90	#define UFFD_EVENT_FORK 0x13
	91	#endif
	92
	93	/* flags for UFFD_EVENT_PAGEFAULT */
	94	#define UFFD_PAGEFAULT_FLAG_WRITE (1<<0) /* If this was a write fault */
	95	#define UFFD_PAGEFAULT_FLAG_WP (1<<1) /* If reason is VM_UFFD_WP */
3f602d27	96
1038628d	97	struct uffdio_api {
a9b85f94	98	/* userland asks for an API number and the features to enable */
1038628d	99	__u64 api;
a9b85f94 AA	100	/*
	101	* Kernel answers below with the all available features for
	102	* the API, this notifies userland of which events and/or
	103	* which flags for each event are enabled in the current
	104	* kernel.
	105	*
	106	* Note: UFFD_EVENT_PAGEFAULT and UFFD_PAGEFAULT_FLAG_WRITE
	107	* are to be considered implicitly always enabled in all kernels as
	108	* long as the uffdio_api.api requested matches UFFD_API.
	109	*/
	110	#if 0 /* not available yet */
	111	#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
	112	#define UFFD_FEATURE_EVENT_FORK (1<<1)
	113	#endif
3f602d27	114	__u64 features;
a9b85f94	115
1038628d AA	116	__u64 ioctls;
	117	};
	118
	119	struct uffdio_range {
	120	__u64 start;
	121	__u64 len;
	122	};
	123
	124	struct uffdio_register {
	125	struct uffdio_range range;
	126	#define UFFDIO_REGISTER_MODE_MISSING ((__u64)1<<0)
	127	#define UFFDIO_REGISTER_MODE_WP ((__u64)1<<1)
	128	__u64 mode;
	129
	130	/*
	131	* kernel answers which ioctl commands are available for the
	132	* range, keep at the end as the last 8 bytes aren't read.
	133	*/
	134	__u64 ioctls;
	135	};
	136
1f1c6f07 AA	137	struct uffdio_copy {
	138	__u64 dst;
	139	__u64 src;
	140	__u64 len;
	141	/*
	142	* There will be a wrprotection flag later that allows to map
	143	* pages wrprotected on the fly. And such a flag will be
	144	* available if the wrprotection ioctl are implemented for the
	145	* range according to the uffdio_register.ioctls.
	146	*/
	147	#define UFFDIO_COPY_MODE_DONTWAKE ((__u64)1<<0)
	148	__u64 mode;
	149
	150	/*
	151	* "copy" is written by the ioctl and must be at the end: the
	152	* copy_from_user will not read the last 8 bytes.
	153	*/
	154	__s64 copy;
	155	};
	156
	157	struct uffdio_zeropage {
	158	struct uffdio_range range;
	159	#define UFFDIO_ZEROPAGE_MODE_DONTWAKE ((__u64)1<<0)
	160	__u64 mode;
	161
	162	/*
	163	* "zeropage" is written by the ioctl and must be at the end:
	164	* the copy_from_user will not read the last 8 bytes.
	165	*/
	166	__s64 zeropage;
	167	};
	168
1038628d	169	#endif /* _LINUX_USERFAULTFD_H */