/* * 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; } __attribute__((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 */