Defines the uAPI of the userfaultfd, notably the ioctl numbers and protocol. Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> --- Documentation/ioctl/ioctl-number.txt | 1 + include/uapi/linux/Kbuild | 1 + include/uapi/linux/userfaultfd.h | 81 ++++++++++++++++++++++++++++++++++++ 3 files changed, 83 insertions(+) create mode 100644 include/uapi/linux/userfaultfd.h diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index ec7c81b..ed950ad 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -302,6 +302,7 @@ Code Seq#(hex) Include File Comments 0xA3 80-8F Port ACL in development: <mailto:tlewis@xxxxxxxxxxxxxx> 0xA3 90-9F linux/dtlk.h +0xAA 00-3F linux/uapi/linux/userfaultfd.h 0xAB 00-1F linux/nbd.h 0xAC 00-1F linux/raw.h 0xAD 00 Netfilter device in development: diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild index 4842a98..47547ea 100644 --- a/include/uapi/linux/Kbuild +++ b/include/uapi/linux/Kbuild @@ -452,3 +452,4 @@ 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..9a8cd56 --- /dev/null +++ b/include/uapi/linux/userfaultfd.h @@ -0,0 +1,81 @@ +/* + * include/linux/userfaultfd.h + * + * Copyright (C) 2007 Davide Libenzi <davidel@xxxxxxxxxxxxxxx> + * Copyright (C) 2015 Red Hat, Inc. + * + */ + +#ifndef _LINUX_USERFAULTFD_H +#define _LINUX_USERFAULTFD_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 */ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>