[PATCH] s390: add ptr_to_compat()

Add ptr_to_compat() to s390 - needed by the new robust-futex code.

Signed-off-by: Ingo Molnar <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Martin Schwidefsky <[e-mail]>

untested. CHECKME: am i right about the 0x7fffffffUL masking?

Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/asm-s390/compat.h

···
 	return (void __user *)(unsigned long)(uptr & 0x7fffffffUL);
 }
 
+static inline compat_uptr_t ptr_to_compat(void __user *uptr)
+{
+	return (u32)(unsigned long)uptr;
+}
+
 static inline void __user *compat_alloc_user_space(long len)
 {
 	unsigned long stack;