userfaultfd: uAPI (1038628d) · Commits · 戴 / test

Documentation/ioctl/ioctl-number.txt

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		@@ -303,6 +303,7 @@ Code Seq#(hex) Include File Comments
		0xA3 80-8F Port ACL in development:
		<mailto:tlewis@mindspring.com>
		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:

include/uapi/linux/Kbuild

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		@@ -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

include/uapi/linux/userfaultfd.h

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		/*
		* 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 */

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