[POWERPC] Mask 32-bit system call arguments to 32 bits on PPC64 in audit code

The system call entry code will clear the high bits of argument
registers before invoking the system call; don't report whatever noise
happens to be in the high bits of the register before that happens.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/ptrace.c

@@ -532,16 +532,22 @@ void do_syscall_trace_enter(struct pt_regs *regs)
 	    && (current->ptrace & PT_PTRACED))
 		do_syscall_trace();
 
-	if (unlikely(current->audit_context))
-		audit_syscall_entry(
-#ifdef CONFIG_PPC32
-				    AUDIT_ARCH_PPC,
-#else
-				    test_thread_flag(TIF_32BIT)?AUDIT_ARCH_PPC:AUDIT_ARCH_PPC64,
+	if (unlikely(current->audit_context)) {
+#ifdef CONFIG_PPC64
+		if (!test_thread_flag(TIF_32BIT))
+			audit_syscall_entry(AUDIT_ARCH_PPC64,
+					    regs->gpr[0],
+					    regs->gpr[3], regs->gpr[4],
+					    regs->gpr[5], regs->gpr[6]);
+		else
 #endif
-				    regs->gpr[0],
-				    regs->gpr[3], regs->gpr[4],
-				    regs->gpr[5], regs->gpr[6]);
+			audit_syscall_entry(AUDIT_ARCH_PPC,
+					    regs->gpr[0],
+					    regs->gpr[3] & 0xffffffff,
+					    regs->gpr[4] & 0xffffffff,
+					    regs->gpr[5] & 0xffffffff,
+					    regs->gpr[6] & 0xffffffff);
+	}
 }
 
 void do_syscall_trace_leave(struct pt_regs *regs)