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 op-
eration 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 spec-
ified 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 speci-
fied range was otherwise invalid.
EAGAIN The process was interrupted; retry this call.
ENOENT The range specified in range is not valid. For example, the vir-
tual 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
Linux man-pages 6.9.1 2024-06-17 UFFDIO_WRITEPROTECT(2const)
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