On Tue, Sep 19, 2023 at 12:02:02PM -0700, Axel Rasmussen wrote: > Several new features have been added to the kernel recently, and the man > page wasn't updated to describe these new features. So, add in > descriptions of any missing features. > > Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx> > --- Patch applied. Thanks, Alex > man2/ioctl_userfaultfd.2 | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 > index e91a1dfc8..53b1f473f 100644 > --- a/man2/ioctl_userfaultfd.2 > +++ b/man2/ioctl_userfaultfd.2 > @@ -204,6 +204,13 @@ If this feature bit is set, > .I uffd_msg.pagefault.feat.ptid > will be set to the faulted thread ID for each page-fault message. > .TP > +.BR UFFD_FEATURE_PAGEFAULT_FLAG_WP " (since Linux 5.10)" > +If this feature bit is set, > +userfaultfd supports write-protect faults > +for anonymous memory. > +(Note that shmem / hugetlbfs support > +is indicated by a separate feature.) > +.TP > .BR UFFD_FEATURE_MINOR_HUGETLBFS " (since Linux 5.13)" > If this feature bit is set, > the kernel supports registering userfaultfd ranges > @@ -221,6 +228,22 @@ will be set to the exact page-fault address that was reported by the hardware, > and will not mask the offset within the page. > Note that old Linux versions might indicate the exact address as well, > even though the feature bit is not set. > +.TP > +.BR UFFD_FEATURE_WP_HUGETLBFS_SHMEM " (since Linux 5.19)" > +If this feature bit is set, > +userfaultfd supports write-protect faults > +for hugetlbfs and shmem / tmpfs memory. > +.TP > +.BR UFFD_FEATURE_WP_UNPOPULATED " (since Linux 6.4)" > +If this feature bit is set, > +the kernel will handle anonymous memory the same way as file memory, > +by allowing the user to write-protect unpopulated ptes. > +.TP > +.BR UFFD_FEATURE_POISON " (since Linux 6.6)" > +If this feature bit is set, > +the kernel supports resolving faults with the > +.B UFFDIO_POISON > +ioctl. > .PP > The returned > .I ioctls > -- > 2.42.0.459.ge4e396fd5e-goog >
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