userfaultfd: buildsystem activation

Orabug: 21685254

This allows to select the userfaultfd during configuration to build it.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Cc: zhang.zhanghailiang@huawei.com
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit a14c151e567cb2c3e62611da808a8bdab86fdee5)
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Dhaval Giani <dhaval.giani@oracle.com>
Conflicts:
	fs/Makefile

Signed-off-by: Dhaval Giani <dhaval.giani@oracle.com>

diff --git a/fs/Makefile b/fs/Makefile
index cb92fd4c31729cc5cf799a3278c57ad3c1af6314..53e59b212a1050728055bd56b9f78b521ee51132 100644 (file)
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_ANON_INODES)     += anon_inodes.o
 obj-$(CONFIG_SIGNALFD)         += signalfd.o
 obj-$(CONFIG_TIMERFD)          += timerfd.o
 obj-$(CONFIG_EVENTFD)          += eventfd.o
+obj-$(CONFIG_USERFAULTFD)      += userfaultfd.o
 obj-$(CONFIG_AIO)               += aio.o
 obj-$(CONFIG_FS_DAX)           += dax.o
 obj-$(CONFIG_FILE_LOCKING)      += locks.o

diff --git a/init/Kconfig b/init/Kconfig
index dc24dec6023292ac6f1bd484ce506074d3e53566..6d68778d9da9cb37ae8cf1ea10edc65f868cf87f 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1574,6 +1574,17 @@ config ADVISE_SYSCALLS
          applications use these syscalls, you can disable this option to save
          space.
 
+config USERFAULTFD
+       bool "Enable userfaultfd() system call"
+       select ANON_INODES
+       default y
+       depends on MMU
+       help
+         Enable the userfaultfd() system call that allows to intercept and
+         handle page faults in userland.
+
+         If unsure, say Y.
+
 config PCI_QUIRKS
        default y
        bool "Enable PCI quirk workarounds" if EXPERT