From 1038628d80e96e3a086189172d9be8eb85ecfabf Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Fri, 4 Sep 2015 15:46:04 -0700 Subject: userfaultfd: uAPI Defines the uAPI of the userfaultfd, notably the ioctl numbers and protocol. Signed-off-by: Andrea Arcangeli Acked-by: Pavel Emelyanov Cc: Sanidhya Kashyap Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" Cc: Andres Lagar-Cavilla Cc: Dave Hansen Cc: Paolo Bonzini Cc: Rik van Riel Cc: Mel Gorman Cc: Andy Lutomirski Cc: Hugh Dickins Cc: Peter Feiner Cc: "Dr. David Alan Gilbert" Cc: Johannes Weiner Cc: "Huangpeng (Peter)" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/uapi/linux/Kbuild | 1 + include/uapi/linux/userfaultfd.h | 83 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 84 insertions(+) create mode 100644 include/uapi/linux/userfaultfd.h (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild index aafb993..70ff1d9 100644 --- a/include/uapi/linux/Kbuild +++ b/include/uapi/linux/Kbuild @@ -456,3 +456,4 @@ header-y += xfrm.h header-y += xilinx-v4l2-controls.h header-y += zorro.h header-y += zorro_ids.h +header-y += userfaultfd.h diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h new file mode 100644 index 0000000..09c2e2a --- /dev/null +++ b/include/uapi/linux/userfaultfd.h @@ -0,0 +1,83 @@ +/* + * include/linux/userfaultfd.h + * + * Copyright (C) 2007 Davide Libenzi + * Copyright (C) 2015 Red Hat, Inc. + * + */ + +#ifndef _LINUX_USERFAULTFD_H +#define _LINUX_USERFAULTFD_H + +#include + +#define UFFD_API ((__u64)0xAA) +/* FIXME: add "|UFFD_BIT_WP" to UFFD_API_BITS after implementing it */ +#define UFFD_API_BITS (UFFD_BIT_WRITE) +#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) + +/* + * 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_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) + +/* + * Valid bits below PAGE_SHIFT in the userfault address read through + * the read() syscall. + */ +#define UFFD_BIT_WRITE (1<<0) /* this was a write fault, MISSING or WP */ +#define UFFD_BIT_WP (1<<1) /* handle_userfault() reason VM_UFFD_WP */ +#define UFFD_BITS 2 /* two above bits used for UFFD_BIT_* mask */ + +struct uffdio_api { + /* userland asks for an API number */ + __u64 api; + + /* kernel answers below with the available features for the API */ + __u64 bits; + __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; +}; + +#endif /* _LINUX_USERFAULTFD_H */ -- cgit v1.1