audit: Add generic compat syscall support

lib/audit.c provides a generic function for auditing system calls.
This patch extends it for compat syscall support on bi-architectures
(32/64-bit) by adding lib/compat_audit.c.
What is required to support this feature are:
 * add asm/unistd32.h for compat system call names
 * select CONFIG_AUDIT_ARCH_COMPAT_GENERIC

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/lib/audit.c b/lib/audit.c
index 76bbed4a..1d726a2 100644
--- a/lib/audit.c
+++ b/lib/audit.c
@@ -30,11 +30,17 @@
 
 int audit_classify_arch(int arch)
 {
-	return 0;
+	if (audit_is_compat(arch))
+		return 1;
+	else
+		return 0;
 }
 
 int audit_classify_syscall(int abi, unsigned syscall)
 {
+	if (audit_is_compat(abi))
+		return audit_classify_compat_syscall(abi, syscall);
+
 	switch(syscall) {
 #ifdef __NR_open
 	case __NR_open:
@@ -57,6 +63,13 @@
 
 static int __init audit_classes_init(void)
 {
+#ifdef CONFIG_AUDIT_COMPAT_GENERIC
+	audit_register_class(AUDIT_CLASS_WRITE_32, compat_write_class);
+	audit_register_class(AUDIT_CLASS_READ_32, compat_read_class);
+	audit_register_class(AUDIT_CLASS_DIR_WRITE_32, compat_dir_class);
+	audit_register_class(AUDIT_CLASS_CHATTR_32, compat_chattr_class);
+	audit_register_class(AUDIT_CLASS_SIGNAL_32, compat_signal_class);
+#endif
 	audit_register_class(AUDIT_CLASS_WRITE, write_class);
 	audit_register_class(AUDIT_CLASS_READ, read_class);
 	audit_register_class(AUDIT_CLASS_DIR_WRITE, dir_class);