refactor(spm-mm): reorganize secure partition manager shim code

In preparation for adding the support for SEL0 SP in EL3 SPMC,
restructure the existing SPM_MM shim code in a way that allows reuse
of the code for both SPM_MM interface and FF-A EL3 SPMC interface. The
code for changing exception levels is identical for both.

With this restructuring of the code, the shim exception code is moved to
the common sub-directory.

Signed-off-by: Sayanta Pattanayak <sayanta.pattanayak@arm.com>
Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Change-Id: Iadda9cf73f12b56e6a1d31fc21b5ba5dc355867f
diff --git a/services/std_svc/spm/common/include/spm_shim_private.h b/services/std_svc/spm/common/include/spm_shim_private.h
new file mode 100644
index 0000000..bcb1147
--- /dev/null
+++ b/services/std_svc/spm/common/include/spm_shim_private.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2017-2023, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SPM_SHIM_PRIVATE_H
+#define SPM_SHIM_PRIVATE_H
+
+#include <stdint.h>
+
+#include <lib/utils_def.h>
+
+/* Assembly source */
+IMPORT_SYM(uintptr_t, spm_shim_exceptions_ptr,		SPM_SHIM_EXCEPTIONS_PTR);
+
+/* Linker symbols */
+IMPORT_SYM(uintptr_t, __SPM_SHIM_EXCEPTIONS_START__,	SPM_SHIM_EXCEPTIONS_START);
+IMPORT_SYM(uintptr_t, __SPM_SHIM_EXCEPTIONS_END__,	SPM_SHIM_EXCEPTIONS_END);
+
+/* Definitions */
+
+#define SPM_SHIM_EXCEPTIONS_SIZE	\
+	(SPM_SHIM_EXCEPTIONS_END - SPM_SHIM_EXCEPTIONS_START)
+
+#endif /* SPM_SHIM_PRIVATE_H */