Add test for patching a system call instruction

tests/test_patching_input.S

Index: tests/test_patching_input.S
diff --git a/tests/test_patching_input.S b/tests/test_patching_input.S
new file mode 100644
index 0000000000000000000000000000000000000000..3e7126d331b1611c792c1496728f0263c223b17b
--- /dev/null
+++ b/tests/test_patching_input.S
@@ -0,0 +1,26 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <asm/unistd.h>
+
+
+        // This performs a system call directly so that we can test
+        // patching this instruction sequence.
+
+        .global my_getpid
+        .global my_getpid_end
+my_getpid:
+        mov $__NR_getpid, %eax
+#if defined(__x86_64__)
+        syscall
+#elif defined(__i386__)
+        int $0x80
+#else
+# error Unsupported target platform
+#endif
+        ret
+my_getpid_end:
+
+        // Tell Linux not to disable no-execute protection for the process.
+        .section .note.GNU-stack,"",@progbits