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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#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;} __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 */