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

NAME LIBRARY SYNOPSIS DESCRIPTION RETURN VALUE ERRORS STANDARDS HISTORY EXAMPLES SEE ALSO

NAME

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

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.