coredump masking: reimplementation of dumpable using two flags

This patch changes mm_struct.dumpable to a pair of bit flags.

set_dumpable() converts three-value dumpable to two flags and stores it into
lower two bits of mm_struct.flags instead of mm_struct.dumpable.
get_dumpable() behaves in the opposite way.

[akpm@linux-foundation.org: export set_dumpable]
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-ia64/processor.h b/include/asm-ia64/processor.h
index db81ba4..6251c764 100644
--- a/include/asm-ia64/processor.h
+++ b/include/asm-ia64/processor.h
@@ -295,9 +295,9 @@
 	regs->ar_bspstore = current->thread.rbs_bot;						\
 	regs->ar_fpsr = FPSR_DEFAULT;								\
 	regs->loadrs = 0;									\
-	regs->r8 = current->mm->dumpable;	/* set "don't zap registers" flag */		\
+	regs->r8 = get_dumpable(current->mm);	/* set "don't zap registers" flag */		\
 	regs->r12 = new_sp - 16;	/* allocate 16 byte scratch area */			\
-	if (unlikely(!current->mm->dumpable)) {							\
+	if (unlikely(!get_dumpable(current->mm))) {							\
 		/*										\
 		 * Zap scratch regs to avoid leaking bits between processes with different	\
 		 * uid/privileges.								\