[deliverable/linux.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>

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