319 lines
9.5 KiB
C
319 lines
9.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
|
|
/*
|
|
* 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>
|
|
|
|
/* ioctls for /dev/userfaultfd */
|
|
#define USERFAULTFD_IOC 0xAA
|
|
#define USERFAULTFD_IOC_NEW _IO(USERFAULTFD_IOC, 0x00)
|
|
|
|
/*
|
|
* If the UFFDIO_API is upgraded someday, the UFFDIO_UNREGISTER and
|
|
* UFFDIO_WAKE ioctls should be defined as _IOW and not as _IOR. In
|
|
* userfaultfd.h we assumed the kernel was reading (instead _IOC_READ
|
|
* means the userland is reading).
|
|
*/
|
|
#define UFFD_API ((__u64)0xAA)
|
|
#define UFFD_API_REGISTER_MODES (UFFDIO_REGISTER_MODE_MISSING | \
|
|
UFFDIO_REGISTER_MODE_WP | \
|
|
UFFDIO_REGISTER_MODE_MINOR)
|
|
#define UFFD_API_FEATURES (UFFD_FEATURE_PAGEFAULT_FLAG_WP | \
|
|
UFFD_FEATURE_EVENT_FORK | \
|
|
UFFD_FEATURE_EVENT_REMAP | \
|
|
UFFD_FEATURE_EVENT_REMOVE | \
|
|
UFFD_FEATURE_EVENT_UNMAP | \
|
|
UFFD_FEATURE_MISSING_HUGETLBFS | \
|
|
UFFD_FEATURE_MISSING_SHMEM | \
|
|
UFFD_FEATURE_SIGBUS | \
|
|
UFFD_FEATURE_THREAD_ID | \
|
|
UFFD_FEATURE_MINOR_HUGETLBFS | \
|
|
UFFD_FEATURE_MINOR_SHMEM | \
|
|
UFFD_FEATURE_EXACT_ADDRESS | \
|
|
UFFD_FEATURE_WP_HUGETLBFS_SHMEM)
|
|
#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 | \
|
|
(__u64)1 << _UFFDIO_WRITEPROTECT | \
|
|
(__u64)1 << _UFFDIO_CONTINUE)
|
|
#define UFFD_API_RANGE_IOCTLS_BASIC \
|
|
((__u64)1 << _UFFDIO_WAKE | \
|
|
(__u64)1 << _UFFDIO_COPY | \
|
|
(__u64)1 << _UFFDIO_CONTINUE | \
|
|
(__u64)1 << _UFFDIO_WRITEPROTECT)
|
|
|
|
/*
|
|
* 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_WRITEPROTECT (0x06)
|
|
#define _UFFDIO_CONTINUE (0x07)
|
|
#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)
|
|
#define UFFDIO_WRITEPROTECT _IOWR(UFFDIO, _UFFDIO_WRITEPROTECT, \
|
|
struct uffdio_writeprotect)
|
|
#define UFFDIO_CONTINUE _IOWR(UFFDIO, _UFFDIO_CONTINUE, \
|
|
struct uffdio_continue)
|
|
|
|
/* read() structure */
|
|
struct uffd_msg {
|
|
__u8 event;
|
|
|
|
__u8 reserved1;
|
|
__u16 reserved2;
|
|
__u32 reserved3;
|
|
|
|
union {
|
|
struct {
|
|
__u64 flags;
|
|
__u64 address;
|
|
union {
|
|
__u32 ptid;
|
|
} feat;
|
|
} pagefault;
|
|
|
|
struct {
|
|
__u32 ufd;
|
|
} fork;
|
|
|
|
struct {
|
|
__u64 from;
|
|
__u64 to;
|
|
__u64 len;
|
|
} remap;
|
|
|
|
struct {
|
|
__u64 start;
|
|
__u64 end;
|
|
} remove;
|
|
|
|
struct {
|
|
/* unused reserved fields */
|
|
__u64 reserved1;
|
|
__u64 reserved2;
|
|
__u64 reserved3;
|
|
} reserved;
|
|
} arg;
|
|
} __packed;
|
|
|
|
/*
|
|
* Start at 0x12 and not at 0 to be more strict against bugs.
|
|
*/
|
|
#define UFFD_EVENT_PAGEFAULT 0x12
|
|
#define UFFD_EVENT_FORK 0x13
|
|
#define UFFD_EVENT_REMAP 0x14
|
|
#define UFFD_EVENT_REMOVE 0x15
|
|
#define UFFD_EVENT_UNMAP 0x16
|
|
|
|
/* 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 */
|
|
#define UFFD_PAGEFAULT_FLAG_MINOR (1<<2) /* If reason is VM_UFFD_MINOR */
|
|
|
|
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.
|
|
*
|
|
* UFFD_FEATURE_MISSING_HUGETLBFS means an UFFDIO_REGISTER
|
|
* with UFFDIO_REGISTER_MODE_MISSING mode will succeed on
|
|
* hugetlbfs virtual memory ranges. Adding or not adding
|
|
* UFFD_FEATURE_MISSING_HUGETLBFS to uffdio_api.features has
|
|
* no real functional effect after UFFDIO_API returns, but
|
|
* it's only useful for an initial feature set probe at
|
|
* UFFDIO_API time. There are two ways to use it:
|
|
*
|
|
* 1) by adding UFFD_FEATURE_MISSING_HUGETLBFS to the
|
|
* uffdio_api.features before calling UFFDIO_API, an error
|
|
* will be returned by UFFDIO_API on a kernel without
|
|
* hugetlbfs missing support
|
|
*
|
|
* 2) the UFFD_FEATURE_MISSING_HUGETLBFS can not be added in
|
|
* uffdio_api.features and instead it will be set by the
|
|
* kernel in the uffdio_api.features if the kernel supports
|
|
* it, so userland can later check if the feature flag is
|
|
* present in uffdio_api.features after UFFDIO_API
|
|
* succeeded.
|
|
*
|
|
* UFFD_FEATURE_MISSING_SHMEM works the same as
|
|
* UFFD_FEATURE_MISSING_HUGETLBFS, but it applies to shmem
|
|
* (i.e. tmpfs and other shmem based APIs).
|
|
*
|
|
* UFFD_FEATURE_SIGBUS feature means no page-fault
|
|
* (UFFD_EVENT_PAGEFAULT) event will be delivered, instead
|
|
* a SIGBUS signal will be sent to the faulting process.
|
|
*
|
|
* UFFD_FEATURE_THREAD_ID pid of the page faulted task_struct will
|
|
* be returned, if feature is not requested 0 will be returned.
|
|
*
|
|
* UFFD_FEATURE_MINOR_HUGETLBFS indicates that minor faults
|
|
* can be intercepted (via REGISTER_MODE_MINOR) for
|
|
* hugetlbfs-backed pages.
|
|
*
|
|
* UFFD_FEATURE_MINOR_SHMEM indicates the same support as
|
|
* UFFD_FEATURE_MINOR_HUGETLBFS, but for shmem-backed pages instead.
|
|
*
|
|
* UFFD_FEATURE_EXACT_ADDRESS indicates that the exact address of page
|
|
* faults would be provided and the offset within the page would not be
|
|
* masked.
|
|
*
|
|
* UFFD_FEATURE_WP_HUGETLBFS_SHMEM indicates that userfaultfd
|
|
* write-protection mode is supported on both shmem and hugetlbfs.
|
|
*/
|
|
#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
|
|
#define UFFD_FEATURE_EVENT_FORK (1<<1)
|
|
#define UFFD_FEATURE_EVENT_REMAP (1<<2)
|
|
#define UFFD_FEATURE_EVENT_REMOVE (1<<3)
|
|
#define UFFD_FEATURE_MISSING_HUGETLBFS (1<<4)
|
|
#define UFFD_FEATURE_MISSING_SHMEM (1<<5)
|
|
#define UFFD_FEATURE_EVENT_UNMAP (1<<6)
|
|
#define UFFD_FEATURE_SIGBUS (1<<7)
|
|
#define UFFD_FEATURE_THREAD_ID (1<<8)
|
|
#define UFFD_FEATURE_MINOR_HUGETLBFS (1<<9)
|
|
#define UFFD_FEATURE_MINOR_SHMEM (1<<10)
|
|
#define UFFD_FEATURE_EXACT_ADDRESS (1<<11)
|
|
#define UFFD_FEATURE_WP_HUGETLBFS_SHMEM (1<<12)
|
|
__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)
|
|
#define UFFDIO_REGISTER_MODE_MINOR ((__u64)1<<2)
|
|
__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;
|
|
#define UFFDIO_COPY_MODE_DONTWAKE ((__u64)1<<0)
|
|
/*
|
|
* UFFDIO_COPY_MODE_WP will map the page write protected on
|
|
* the fly. UFFDIO_COPY_MODE_WP is available only if the
|
|
* write protected ioctl is implemented for the range
|
|
* according to the uffdio_register.ioctls.
|
|
*/
|
|
#define UFFDIO_COPY_MODE_WP ((__u64)1<<1)
|
|
__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;
|
|
};
|
|
|
|
struct uffdio_writeprotect {
|
|
struct uffdio_range range;
|
|
/*
|
|
* UFFDIO_WRITEPROTECT_MODE_WP: set the flag to write protect a range,
|
|
* unset the flag to undo protection of a range which was previously
|
|
* write protected.
|
|
*
|
|
* UFFDIO_WRITEPROTECT_MODE_DONTWAKE: set the flag to avoid waking up
|
|
* any wait thread after the operation succeeds.
|
|
*
|
|
* NOTE: Write protecting a region (WP=1) is unrelated to page faults,
|
|
* therefore DONTWAKE flag is meaningless with WP=1. Removing write
|
|
* protection (WP=0) in response to a page fault wakes the faulting
|
|
* task unless DONTWAKE is set.
|
|
*/
|
|
#define UFFDIO_WRITEPROTECT_MODE_WP ((__u64)1<<0)
|
|
#define UFFDIO_WRITEPROTECT_MODE_DONTWAKE ((__u64)1<<1)
|
|
__u64 mode;
|
|
};
|
|
|
|
struct uffdio_continue {
|
|
struct uffdio_range range;
|
|
#define UFFDIO_CONTINUE_MODE_DONTWAKE ((__u64)1<<0)
|
|
__u64 mode;
|
|
|
|
/*
|
|
* Fields below here are written by the ioctl and must be at the end:
|
|
* the copy_from_user will not read past here.
|
|
*/
|
|
__s64 mapped;
|
|
};
|
|
|
|
/*
|
|
* Flags for the userfaultfd(2) system call itself.
|
|
*/
|
|
|
|
/*
|
|
* Create a userfaultfd that can handle page faults only in user mode.
|
|
*/
|
|
#define UFFD_USER_MODE_ONLY 1
|
|
|
|
#endif /* _LINUX_USERFAULTFD_H */
|