UFFDIO_WRITEPROTECT(2const) - Linux manual page (original) (raw)

UFFDIOWRITEPROTECT(2const) UFFDIOWRITEPROTECT(2const)

NAME top

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

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#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 top

   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 top

   On success, 0 is returned.  On error, -1 is returned and _[errno](../man3/errno.3.html)_ is
   set to indicate the error.

ERRORS top

   **EINVAL** The _start_ or the _len_ field of the _ufdiorange_ 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 top

   Linux.

HISTORY top

   Linux 5.7.

EXAMPLES top

   See [userfaultfd(2)](../man2/userfaultfd.2.html).

SEE ALSO top

   [ioctl(2)](../man2/ioctl.2.html), [ioctl_userfaultfd(2)](../man2/ioctl%5Fuserfaultfd.2.html), [userfaultfd(2)](../man2/userfaultfd.2.html)

   _Documentation/admin-guide/mm/userfaultfd.rst_ in the Linux kernel
   source tree

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Linux man-pages 6.10 2024-07-23 UFFDIOWRITEPROTECT(2const)

Pages that refer to this page:ioctl_userfaultfd(2)