sparc: Align clone and signal stacks to 16 bytes.

This is mandatory for 64-bit processes, and doing it also for 32-bit
processes saves a conditional in the compat case.

This fixes the glibc/nptl/tst-stdio1 test case, as well
as many others, on 64-bit.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index 18d6785..6679eeb 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -406,11 +406,11 @@
 	} else
 		__get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
 
-	/* Now 8-byte align the stack as this is mandatory in the
-	 * Sparc ABI due to how register windows work.  This hides
-	 * the restriction from thread libraries etc.  -DaveM
+	/* Now align the stack as this is mandatory in the Sparc ABI
+	 * due to how register windows work.  This hides the
+	 * restriction from thread libraries etc.
 	 */
-	csp &= ~7UL;
+	csp &= ~15UL;
 
 	distance = fp - psp;
 	rval = (csp - distance);