Add a paragraph for UFFD_USER_MODE_ONLY flag that was introduced in Linux 5.11. Signed-off-by: Peter Xu <peterx@xxxxxxxxxx> --- man2/userfaultfd.2 | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2 index cee7c01d2..0928a76d2 100644 --- a/man2/userfaultfd.2 +++ b/man2/userfaultfd.2 @@ -29,8 +29,9 @@ userfaultfd \- create a file descriptor for handling page faults in user space .SH SYNOPSIS .nf -.BR "#include <fcntl.h>" " /* Definition of " O_* " constants */" -.BR "#include <sys/syscall.h>" " /* Definition of " SYS_* " constants */" +.BR "#include <fcntl.h>" " /* Definition of " O_* " constants */" +.BR "#include <sys/syscall.h>" " /* Definition of " SYS_* " constants */" +.BR "#include <linux/userfaultfd.h>" " /* Definition of " UFFD_* " constants */" .B #include <unistd.h> .PP .BI "int syscall(SYS_userfaultfd, int " flags ); @@ -76,6 +77,15 @@ See the description of the .BR O_NONBLOCK flag in .BR open (2). +.TP +.BR UFFD_USER_MODE_ONLY +This is an userfaultfd specific flag that was introduced since Linux 5.11. +When set, the userfaultfd object will only be able to handle page faults +originated from the userspace on the registered regions. +When a kernel originated fault was triggered on the registered range with +this userfaultfd, a +.BR SIGBUS +signal will be delivered. .PP When the last file descriptor referring to a userfaultfd object is closed, all memory ranges that were registered with the object are unregistered -- 2.32.0
