diff options
author | Andrea Arcangeli <aarcange@redhat.com> | 2015-09-05 01:46:04 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-05 02:54:41 +0300 |
commit | 1038628d80e96e3a086189172d9be8eb85ecfabf (patch) | |
tree | 50d970e531405f4a472ffc52070f749591a4dfa2 /include/uapi/linux/userfaultfd.h | |
parent | 51360155eccb907ff8635bd10fc7de876408c2e0 (diff) | |
download | linux-1038628d80e96e3a086189172d9be8eb85ecfabf.tar.xz |
userfaultfd: uAPI
Defines the uAPI of the userfaultfd, notably the ioctl numbers and protocol.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Cc: zhang.zhanghailiang@huawei.com
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/uapi/linux/userfaultfd.h')
-rw-r--r-- | include/uapi/linux/userfaultfd.h | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h new file mode 100644 index 000000000000..09c2e2a8c9d6 --- /dev/null +++ b/include/uapi/linux/userfaultfd.h @@ -0,0 +1,83 @@ +/* + * 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) +/* 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 */ |