1 files changed, 60 insertions, 3 deletions

diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
index b5379c0e6d6d..68fc052dc09b 100644
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -5,6 +5,7 @@
 #include <linux/futex.h>
 #include <linux/rtmutex.h>
 #include <linux/sched/wake_q.h>
+#include <linux/compat.h>
 
 #ifdef CONFIG_PREEMPT_RT
 #include <linux/rcuwait.h>
@@ -16,8 +17,15 @@
  * Futex flags used to encode options to functions and preserve them across
  * restarts.
  */
+#define FLAGS_SIZE_8		0x00
+#define FLAGS_SIZE_16		0x01
+#define FLAGS_SIZE_32		0x02
+#define FLAGS_SIZE_64		0x03
+
+#define FLAGS_SIZE_MASK		0x03
+
 #ifdef CONFIG_MMU
-# define FLAGS_SHARED		0x01
+# define FLAGS_SHARED		0x10
 #else
 /*
  * NOMMU does not have per process address space. Let the compiler optimize
@@ -25,8 +33,57 @@
  */
 # define FLAGS_SHARED		0x00
 #endif
-#define FLAGS_CLOCKRT		0x02
-#define FLAGS_HAS_TIMEOUT	0x04
+#define FLAGS_CLOCKRT		0x20
+#define FLAGS_HAS_TIMEOUT	0x40
+#define FLAGS_NUMA		0x80
+
+/* FUTEX_ to FLAGS_ */
+static inline unsigned int futex_to_flags(unsigned int op)
+{
+	unsigned int flags = FLAGS_SIZE_32;
+
+	if (!(op & FUTEX_PRIVATE_FLAG))
+		flags |= FLAGS_SHARED;
+
+	if (op & FUTEX_CLOCK_REALTIME)
+		flags |= FLAGS_CLOCKRT;
+
+	return flags;
+}
+
+/* FUTEX2_ to FLAGS_ */
+static inline unsigned int futex2_to_flags(unsigned int flags2)
+{
+	unsigned int flags = flags2 & FUTEX2_SIZE_MASK;
+
+	if (!(flags2 & FUTEX2_PRIVATE))
+		flags |= FLAGS_SHARED;
+
+	if (flags2 & FUTEX2_NUMA)
+		flags |= FLAGS_NUMA;
+
+	return flags;
+}
+
+static inline unsigned int futex_size(unsigned int flags)
+{
+	return 1 << (flags & FLAGS_SIZE_MASK);
+}
+
+static inline bool futex_flags_valid(unsigned int flags)
+{
+	/* Only 64bit futexes for 64bit code */
+	if (!IS_ENABLED(CONFIG_64BIT) || in_compat_syscall()) {
+		if ((flags & FLAGS_SIZE_MASK) == FLAGS_SIZE_64)
+			return false;
+	}
+
+	/* Only 32bit futexes are implemented -- for now */
+	if ((flags & FLAGS_SIZE_MASK) != FLAGS_SIZE_32)
+		return false;
+
+	return true;
+}
 
 #ifdef CONFIG_FAIL_FUTEX
 extern bool should_fail_futex(bool fshared);