UFFDIO_WRITEPROTECT(2const) — Linux manual page

UFFDIO_WRITEPROTECT(2const)                  UFFDIO_WRITEPROTECT(2const)

NAME

       UFFDIO_WRITEPROTECT - write-protect or write-unprotect a
       userfaultfd-registered memory range

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <linux/userfaultfd.h>  /* Definition of UFFD* constants */
       #include <sys/ioctl.h>

       int ioctl(int fd, UFFDIO_WRITEPROTECT, ...);

       #include <linux/userfaultfd.h>

       struct uffdio_writeprotect {
           struct uffdio_range  range;  /* Range to change write permission*/
           __u64                mode;   /* Mode to change write permission */
       };

DESCRIPTION

       Write-protect or write-unprotect a userfaultfd-registered memory
       range registered with mode UFFDIO_REGISTER_MODE_WP.

       There are two mode bits that are supported in this structure:

       UFFDIO_WRITEPROTECT_MODE_WP
              When this mode bit is set, the ioctl will be a write-
              protect operation upon the memory range specified by
              range.  Otherwise it will be a write-unprotect operation
              upon the specified range, which can be used to resolve a
              userfaultfd write-protect page fault.

       UFFDIO_WRITEPROTECT_MODE_DONTWAKE
              When this mode bit is set, do not wake up any thread that
              waits for page-fault resolution after the operation.  This
              can be specified only if UFFDIO_WRITEPROTECT_MODE_WP is
              not specified.

RETURN VALUE

       On success, 0 is returned.  On error, -1 is returned and errno is
       set to indicate the error.

ERRORS

       EINVAL The start or the len field of the ufdio_range structure
              was not a multiple of the system page size; or len was
              zero; or the specified range was otherwise invalid.

       EAGAIN The process was interrupted; retry this call.

       ENOENT The range specified in range is not valid.  For example,
              the virtual address does not exist, or not registered with
              userfaultfd write-protect mode.

       EFAULT Encountered a generic fault during processing.

STANDARDS

       Linux.

HISTORY

       Linux 5.7.

EXAMPLES

       See userfaultfd(2).

SEE ALSO

       ioctl(2), ioctl_userfaultfd(2), userfaultfd(2)

       Documentation/admin-guide/mm/userfaultfd.rst in the Linux kernel
       source tree

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Linux man-pages 6.9.1          2024-06-17    UFFDIO_WRITEPROTECT(2const)

Pages that refer to this page: ioctl_userfaultfd(2)

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