refactor(spm_mm): reorganize secure partition manager code

In preparation for adding the EL3 SPMC configuration as defined in
the FF-A specification, restructure the existing SPM_MM code.

With this restructuring of the code, the 'spm_mm' directory is
renamed as 'spm' and the code inside has been split into two
sub-directories named 'common' and 'spm_mm'. The code in 'spm_mm'
directory contains the code that implements the MM interface.
In subsequent patches, the 'spmc' directory will be introduced
under the 'spm' directory providing the code that implements
the 'FF-A' interface.

Currently the common functionality for S-EL1 partitions is
limited to assembler functions to enter and exit an SP
synchronously.

Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>
Change-Id: I37739b9b53bc68e151ab5c1c0c6a15b3ee362241
diff --git a/services/std_svc/spm/spm_mm/aarch64/spm_mm_shim_exceptions.S b/services/std_svc/spm/spm_mm/aarch64/spm_mm_shim_exceptions.S
new file mode 100644
index 0000000..836f75c
--- /dev/null
+++ b/services/std_svc/spm/spm_mm/aarch64/spm_mm_shim_exceptions.S
@@ -0,0 +1,128 @@
+/*
+ * Copyright (c) 2017-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <common/bl_common.h>
+#include <context.h>
+
+/* -----------------------------------------------------------------------------
+ * Very simple stackless exception handlers used by the spm shim layer.
+ * -----------------------------------------------------------------------------
+ */
+	.globl	spm_shim_exceptions_ptr
+
+vector_base spm_shim_exceptions_ptr, .spm_shim_exceptions
+
+	/* -----------------------------------------------------
+	 * Current EL with SP0 : 0x0 - 0x200
+	 * -----------------------------------------------------
+	 */
+vector_entry SynchronousExceptionSP0, .spm_shim_exceptions
+	b	.
+end_vector_entry SynchronousExceptionSP0
+
+vector_entry IrqSP0, .spm_shim_exceptions
+	b	.
+end_vector_entry IrqSP0
+
+vector_entry FiqSP0, .spm_shim_exceptions
+	b	.
+end_vector_entry FiqSP0
+
+vector_entry SErrorSP0, .spm_shim_exceptions
+	b	.
+end_vector_entry SErrorSP0
+
+	/* -----------------------------------------------------
+	 * Current EL with SPx: 0x200 - 0x400
+	 * -----------------------------------------------------
+	 */
+vector_entry SynchronousExceptionSPx, .spm_shim_exceptions
+	b	.
+end_vector_entry SynchronousExceptionSPx
+
+vector_entry IrqSPx, .spm_shim_exceptions
+	b	.
+end_vector_entry IrqSPx
+
+vector_entry FiqSPx, .spm_shim_exceptions
+	b	.
+end_vector_entry FiqSPx
+
+vector_entry SErrorSPx, .spm_shim_exceptions
+	b	.
+end_vector_entry SErrorSPx
+
+	/* -----------------------------------------------------
+	 * Lower EL using AArch64 : 0x400 - 0x600. No exceptions
+	 * are handled since secure_partition does not implement
+	 * a lower EL
+	 * -----------------------------------------------------
+	 */
+vector_entry SynchronousExceptionA64, .spm_shim_exceptions
+	msr	tpidr_el1, x30
+	mrs	x30, esr_el1
+	ubfx	x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH
+
+	cmp	x30, #EC_AARCH64_SVC
+	b.eq 	do_smc
+
+	cmp	x30, #EC_AARCH32_SVC
+	b.eq	do_smc
+
+	cmp	x30, #EC_AARCH64_SYS
+	b.eq	handle_sys_trap
+
+	/* Fail in all the other cases */
+	b	panic
+
+	/* ---------------------------------------------
+	 * Tell SPM that we are done initialising
+	 * ---------------------------------------------
+	 */
+do_smc:
+	mrs	x30, tpidr_el1
+	smc	#0
+	exception_return
+
+	/* AArch64 system instructions trap are handled as a panic for now */
+handle_sys_trap:
+panic:
+	b	panic
+end_vector_entry SynchronousExceptionA64
+
+vector_entry IrqA64, .spm_shim_exceptions
+	b	.
+end_vector_entry IrqA64
+
+vector_entry FiqA64, .spm_shim_exceptions
+	b	.
+end_vector_entry FiqA64
+
+vector_entry SErrorA64, .spm_shim_exceptions
+	b	.
+end_vector_entry SErrorA64
+
+	/* -----------------------------------------------------
+	 * Lower EL using AArch32 : 0x600 - 0x800
+	 * -----------------------------------------------------
+	 */
+vector_entry SynchronousExceptionA32, .spm_shim_exceptions
+	b	.
+end_vector_entry SynchronousExceptionA32
+
+vector_entry IrqA32, .spm_shim_exceptions
+	b	.
+end_vector_entry IrqA32
+
+vector_entry FiqA32, .spm_shim_exceptions
+	b	.
+end_vector_entry FiqA32
+
+vector_entry SErrorA32, .spm_shim_exceptions
+	b	.
+end_vector_entry SErrorA32