/* * 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)
/* * 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;
/* * 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;
};
/* * "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;
};
/* * 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 */
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