/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note *//* *  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> /* ioctls for /dev/userfaultfd */#define USERFAULTFD_IOC 0xAA#define USERFAULTFD_IOC_NEW _IO(USERFAULTFD_IOC, 0x00) /* * If the UFFDIO_API is upgraded someday, the UFFDIO_UNREGISTER and * UFFDIO_WAKE ioctls should be defined as _IOW and not as _IOR.  In * userfaultfd.h we assumed the kernel was reading (instead _IOC_READ * means the userland is reading). */#define UFFD_API ((__u64)0xAA)#define UFFD_API_REGISTER_MODES (UFFDIO_REGISTER_MODE_MISSING |	\				 UFFDIO_REGISTER_MODE_WP |	\				 UFFDIO_REGISTER_MODE_MINOR)#define UFFD_API_FEATURES (UFFD_FEATURE_PAGEFAULT_FLAG_WP |	\			   UFFD_FEATURE_EVENT_FORK |		\			   UFFD_FEATURE_EVENT_REMAP |		\			   UFFD_FEATURE_EVENT_REMOVE |		\			   UFFD_FEATURE_EVENT_UNMAP |		\			   UFFD_FEATURE_MISSING_HUGETLBFS |	\			   UFFD_FEATURE_MISSING_SHMEM |		\			   UFFD_FEATURE_SIGBUS |		\			   UFFD_FEATURE_THREAD_ID |		\			   UFFD_FEATURE_MINOR_HUGETLBFS |	\			   UFFD_FEATURE_MINOR_SHMEM |		\			   UFFD_FEATURE_EXACT_ADDRESS |		\			   UFFD_FEATURE_WP_HUGETLBFS_SHMEM |	\			   UFFD_FEATURE_WP_UNPOPULATED |	\			   UFFD_FEATURE_POISON |		\			   UFFD_FEATURE_WP_ASYNC |		\			   UFFD_FEATURE_MOVE)#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 |		\	 (__u64)1 << _UFFDIO_MOVE |		\	 (__u64)1 << _UFFDIO_WRITEPROTECT |	\	 (__u64)1 << _UFFDIO_CONTINUE |		\	 (__u64)1 << _UFFDIO_POISON)#define UFFD_API_RANGE_IOCTLS_BASIC		\	((__u64)1 << _UFFDIO_WAKE |		\	 (__u64)1 << _UFFDIO_COPY |		\	 (__u64)1 << _UFFDIO_WRITEPROTECT |	\	 (__u64)1 << _UFFDIO_CONTINUE |		\	 (__u64)1 << _UFFDIO_POISON) /* * 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_MOVE			(0x05)#define _UFFDIO_WRITEPROTECT		(0x06)#define _UFFDIO_CONTINUE		(0x07)#define _UFFDIO_POISON			(0x08)#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)#define UFFDIO_MOVE		_IOWR(UFFDIO, _UFFDIO_MOVE,	\				      struct uffdio_move)#define UFFDIO_WRITEPROTECT	_IOWR(UFFDIO, _UFFDIO_WRITEPROTECT, \				      struct uffdio_writeprotect)#define UFFDIO_CONTINUE		_IOWR(UFFDIO, _UFFDIO_CONTINUE,	\				      struct uffdio_continue)#define UFFDIO_POISON		_IOWR(UFFDIO, _UFFDIO_POISON, \				      struct uffdio_poison) /* read() structure */struct uffd_msg {	__u8	event; 	__u8	reserved1;	__u16	reserved2;	__u32	reserved3; 	union {		struct {			__u64	flags;			__u64	address;			union {				__u32 ptid;			} feat;		} pagefault; 		struct {			__u32	ufd;		} fork; 		struct {			__u64	from;			__u64	to;			__u64	len;		} remap; 		struct {			__u64	start;			__u64	end;		} remove; 		struct {			/* unused reserved fields */			__u64	reserved1;			__u64	reserved2;			__u64	reserved3;		} reserved;	} arg;} __attribute__((packed)); /* * Start at 0x12 and not at 0 to be more strict against bugs. */#define UFFD_EVENT_PAGEFAULT	0x12#define UFFD_EVENT_FORK		0x13#define UFFD_EVENT_REMAP	0x14#define UFFD_EVENT_REMOVE	0x15#define UFFD_EVENT_UNMAP	0x16 /* 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 */#define UFFD_PAGEFAULT_FLAG_MINOR	(1<<2)	/* If reason is VM_UFFD_MINOR */ 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.	 *	 * UFFD_FEATURE_MISSING_HUGETLBFS means an UFFDIO_REGISTER	 * with UFFDIO_REGISTER_MODE_MISSING mode will succeed on	 * hugetlbfs virtual memory ranges. Adding or not adding	 * UFFD_FEATURE_MISSING_HUGETLBFS to uffdio_api.features has	 * no real functional effect after UFFDIO_API returns, but	 * it's only useful for an initial feature set probe at	 * UFFDIO_API time. There are two ways to use it:	 *	 * 1) by adding UFFD_FEATURE_MISSING_HUGETLBFS to the	 *    uffdio_api.features before calling UFFDIO_API, an error	 *    will be returned by UFFDIO_API on a kernel without	 *    hugetlbfs missing support	 *	 * 2) the UFFD_FEATURE_MISSING_HUGETLBFS can not be added in	 *    uffdio_api.features and instead it will be set by the	 *    kernel in the uffdio_api.features if the kernel supports	 *    it, so userland can later check if the feature flag is	 *    present in uffdio_api.features after UFFDIO_API	 *    succeeded.	 *	 * UFFD_FEATURE_MISSING_SHMEM works the same as	 * UFFD_FEATURE_MISSING_HUGETLBFS, but it applies to shmem	 * (i.e. tmpfs and other shmem based APIs).	 *	 * UFFD_FEATURE_SIGBUS feature means no page-fault	 * (UFFD_EVENT_PAGEFAULT) event will be delivered, instead	 * a SIGBUS signal will be sent to the faulting process.	 *	 * UFFD_FEATURE_THREAD_ID pid of the page faulted task_struct will	 * be returned, if feature is not requested 0 will be returned.	 *	 * UFFD_FEATURE_MINOR_HUGETLBFS indicates that minor faults	 * can be intercepted (via REGISTER_MODE_MINOR) for	 * hugetlbfs-backed pages.	 *	 * UFFD_FEATURE_MINOR_SHMEM indicates the same support as	 * UFFD_FEATURE_MINOR_HUGETLBFS, but for shmem-backed pages instead.	 *	 * UFFD_FEATURE_EXACT_ADDRESS indicates that the exact address of page	 * faults would be provided and the offset within the page would not be	 * masked.	 *	 * UFFD_FEATURE_WP_HUGETLBFS_SHMEM indicates that userfaultfd	 * write-protection mode is supported on both shmem and hugetlbfs.	 *	 * UFFD_FEATURE_WP_UNPOPULATED indicates that userfaultfd	 * write-protection mode will always apply to unpopulated pages	 * (i.e. empty ptes).  This will be the default behavior for shmem	 * & hugetlbfs, so this flag only affects anonymous memory behavior	 * when userfault write-protection mode is registered.	 *	 * UFFD_FEATURE_WP_ASYNC indicates that userfaultfd write-protection	 * asynchronous mode is supported in which the write fault is	 * automatically resolved and write-protection is un-set.	 * It implies UFFD_FEATURE_WP_UNPOPULATED.	 *	 * UFFD_FEATURE_MOVE indicates that the kernel supports moving an	 * existing page contents from userspace.	 */#define UFFD_FEATURE_PAGEFAULT_FLAG_WP		(1<<0)#define UFFD_FEATURE_EVENT_FORK			(1<<1)#define UFFD_FEATURE_EVENT_REMAP		(1<<2)#define UFFD_FEATURE_EVENT_REMOVE		(1<<3)#define UFFD_FEATURE_MISSING_HUGETLBFS		(1<<4)#define UFFD_FEATURE_MISSING_SHMEM		(1<<5)#define UFFD_FEATURE_EVENT_UNMAP		(1<<6)#define UFFD_FEATURE_SIGBUS			(1<<7)#define UFFD_FEATURE_THREAD_ID			(1<<8)#define UFFD_FEATURE_MINOR_HUGETLBFS		(1<<9)#define UFFD_FEATURE_MINOR_SHMEM		(1<<10)#define UFFD_FEATURE_EXACT_ADDRESS		(1<<11)#define UFFD_FEATURE_WP_HUGETLBFS_SHMEM		(1<<12)#define UFFD_FEATURE_WP_UNPOPULATED		(1<<13)#define UFFD_FEATURE_POISON			(1<<14)#define UFFD_FEATURE_WP_ASYNC			(1<<15)#define UFFD_FEATURE_MOVE			(1<<16)	__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)#define UFFDIO_REGISTER_MODE_MINOR	((__u64)1<<2)	__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;#define UFFDIO_COPY_MODE_DONTWAKE		((__u64)1<<0)	/*	 * UFFDIO_COPY_MODE_WP will map the page write protected on	 * the fly.  UFFDIO_COPY_MODE_WP is available only if the	 * write protected ioctl is implemented for the range	 * according to the uffdio_register.ioctls.	 */#define UFFDIO_COPY_MODE_WP			((__u64)1<<1)	__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;}; struct uffdio_writeprotect {	struct uffdio_range range;/* * UFFDIO_WRITEPROTECT_MODE_WP: set the flag to write protect a range, * unset the flag to undo protection of a range which was previously * write protected. * * UFFDIO_WRITEPROTECT_MODE_DONTWAKE: set the flag to avoid waking up * any wait thread after the operation succeeds. * * NOTE: Write protecting a region (WP=1) is unrelated to page faults, * therefore DONTWAKE flag is meaningless with WP=1.  Removing write * protection (WP=0) in response to a page fault wakes the faulting * task unless DONTWAKE is set. */#define UFFDIO_WRITEPROTECT_MODE_WP		((__u64)1<<0)#define UFFDIO_WRITEPROTECT_MODE_DONTWAKE	((__u64)1<<1)	__u64 mode;}; struct uffdio_continue {	struct uffdio_range range;#define UFFDIO_CONTINUE_MODE_DONTWAKE		((__u64)1<<0)	/*	 * UFFDIO_CONTINUE_MODE_WP will map the page write protected on	 * the fly.  UFFDIO_CONTINUE_MODE_WP is available only if the	 * write protected ioctl is implemented for the range	 * according to the uffdio_register.ioctls.	 */#define UFFDIO_CONTINUE_MODE_WP			((__u64)1<<1)	__u64 mode; 	/*	 * Fields below here are written by the ioctl and must be at the end:	 * the copy_from_user will not read past here.	 */	__s64 mapped;}; struct uffdio_poison {	struct uffdio_range range;#define UFFDIO_POISON_MODE_DONTWAKE		((__u64)1<<0)	__u64 mode; 	/*	 * Fields below here are written by the ioctl and must be at the end:	 * the copy_from_user will not read past here.	 */	__s64 updated;}; struct uffdio_move {	__u64 dst;	__u64 src;	__u64 len;	/*	 * Especially if used to atomically remove memory from the	 * address space the wake on the dst range is not needed.	 */#define UFFDIO_MOVE_MODE_DONTWAKE		((__u64)1<<0)#define UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES	((__u64)1<<1)	__u64 mode;	/*	 * "move" is written by the ioctl and must be at the end: the	 * copy_from_user will not read the last 8 bytes.	 */	__s64 move;}; /* * Flags for the userfaultfd(2) system call itself. */ /* * Create a userfaultfd that can handle page faults only in user mode. */#define UFFD_USER_MODE_ONLY 1 #endif /* _LINUX_USERFAULTFD_H */