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/spm_mm_main.c b/services/std_svc/spm/spm_mm/spm_mm_main.c
new file mode 100644
index 0000000..e71e65b
--- /dev/null
+++ b/services/std_svc/spm/spm_mm/spm_mm_main.c
@@ -0,0 +1,354 @@
+/*
+ * Copyright (c) 2017-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch_helpers.h>
+#include <assert.h>
+#include <errno.h>
+
+#include <bl31/bl31.h>
+#include <bl31/ehf.h>
+#include <common/debug.h>
+#include <common/runtime_svc.h>
+#include <lib/el3_runtime/context_mgmt.h>
+#include <lib/smccc.h>
+#include <lib/spinlock.h>
+#include <lib/utils.h>
+#include <lib/xlat_tables/xlat_tables_v2.h>
+#include <plat/common/platform.h>
+#include <services/spm_mm_partition.h>
+#include <services/spm_mm_svc.h>
+#include <smccc_helpers.h>
+
+#include "spm_common.h"
+#include "spm_mm_private.h"
+
+/*******************************************************************************
+ * Secure Partition context information.
+ ******************************************************************************/
+static sp_context_t sp_ctx;
+
+/*******************************************************************************
+ * Set state of a Secure Partition context.
+ ******************************************************************************/
+void sp_state_set(sp_context_t *sp_ptr, sp_state_t state)
+{
+	spin_lock(&(sp_ptr->state_lock));
+	sp_ptr->state = state;
+	spin_unlock(&(sp_ptr->state_lock));
+}
+
+/*******************************************************************************
+ * Wait until the state of a Secure Partition is the specified one and change it
+ * to the desired state.
+ ******************************************************************************/
+void sp_state_wait_switch(sp_context_t *sp_ptr, sp_state_t from, sp_state_t to)
+{
+	int success = 0;
+
+	while (success == 0) {
+		spin_lock(&(sp_ptr->state_lock));
+
+		if (sp_ptr->state == from) {
+			sp_ptr->state = to;
+
+			success = 1;
+		}
+
+		spin_unlock(&(sp_ptr->state_lock));
+	}
+}
+
+/*******************************************************************************
+ * Check if the state of a Secure Partition is the specified one and, if so,
+ * change it to the desired state. Returns 0 on success, -1 on error.
+ ******************************************************************************/
+int sp_state_try_switch(sp_context_t *sp_ptr, sp_state_t from, sp_state_t to)
+{
+	int ret = -1;
+
+	spin_lock(&(sp_ptr->state_lock));
+
+	if (sp_ptr->state == from) {
+		sp_ptr->state = to;
+
+		ret = 0;
+	}
+
+	spin_unlock(&(sp_ptr->state_lock));
+
+	return ret;
+}
+
+/*******************************************************************************
+ * This function takes an SP context pointer and performs a synchronous entry
+ * into it.
+ ******************************************************************************/
+static uint64_t spm_sp_synchronous_entry(sp_context_t *ctx)
+{
+	uint64_t rc;
+
+	assert(ctx != NULL);
+
+	/* Assign the context of the SP to this CPU */
+	cm_set_context(&(ctx->cpu_ctx), SECURE);
+
+	/* Restore the context assigned above */
+	cm_el1_sysregs_context_restore(SECURE);
+	cm_set_next_eret_context(SECURE);
+
+	/* Invalidate TLBs at EL1. */
+	tlbivmalle1();
+	dsbish();
+
+	/* Enter Secure Partition */
+	rc = spm_secure_partition_enter(&ctx->c_rt_ctx);
+
+	/* Save secure state */
+	cm_el1_sysregs_context_save(SECURE);
+
+	return rc;
+}
+
+/*******************************************************************************
+ * This function returns to the place where spm_sp_synchronous_entry() was
+ * called originally.
+ ******************************************************************************/
+__dead2 static void spm_sp_synchronous_exit(uint64_t rc)
+{
+	sp_context_t *ctx = &sp_ctx;
+
+	/*
+	 * The SPM must have initiated the original request through a
+	 * synchronous entry into the secure partition. Jump back to the
+	 * original C runtime context with the value of rc in x0;
+	 */
+	spm_secure_partition_exit(ctx->c_rt_ctx, rc);
+
+	panic();
+}
+
+/*******************************************************************************
+ * Jump to each Secure Partition for the first time.
+ ******************************************************************************/
+static int32_t spm_init(void)
+{
+	uint64_t rc;
+	sp_context_t *ctx;
+
+	INFO("Secure Partition init...\n");
+
+	ctx = &sp_ctx;
+
+	ctx->state = SP_STATE_RESET;
+
+	rc = spm_sp_synchronous_entry(ctx);
+	assert(rc == 0);
+
+	ctx->state = SP_STATE_IDLE;
+
+	INFO("Secure Partition initialized.\n");
+
+	return !rc;
+}
+
+/*******************************************************************************
+ * Initialize contexts of all Secure Partitions.
+ ******************************************************************************/
+int32_t spm_mm_setup(void)
+{
+	sp_context_t *ctx;
+
+	/* Disable MMU at EL1 (initialized by BL2) */
+	disable_mmu_icache_el1();
+
+	/* Initialize context of the SP */
+	INFO("Secure Partition context setup start...\n");
+
+	ctx = &sp_ctx;
+
+	/* Assign translation tables context. */
+	ctx->xlat_ctx_handle = spm_get_sp_xlat_context();
+
+	spm_sp_setup(ctx);
+
+	/* Register init function for deferred init.  */
+	bl31_register_bl32_init(&spm_init);
+
+	INFO("Secure Partition setup done.\n");
+
+	return 0;
+}
+
+/*******************************************************************************
+ * Function to perform a call to a Secure Partition.
+ ******************************************************************************/
+uint64_t spm_mm_sp_call(uint32_t smc_fid, uint64_t x1, uint64_t x2, uint64_t x3)
+{
+	uint64_t rc;
+	sp_context_t *sp_ptr = &sp_ctx;
+
+	/* Wait until the Secure Partition is idle and set it to busy. */
+	sp_state_wait_switch(sp_ptr, SP_STATE_IDLE, SP_STATE_BUSY);
+
+	/* Set values for registers on SP entry */
+	cpu_context_t *cpu_ctx = &(sp_ptr->cpu_ctx);
+
+	write_ctx_reg(get_gpregs_ctx(cpu_ctx), CTX_GPREG_X0, smc_fid);
+	write_ctx_reg(get_gpregs_ctx(cpu_ctx), CTX_GPREG_X1, x1);
+	write_ctx_reg(get_gpregs_ctx(cpu_ctx), CTX_GPREG_X2, x2);
+	write_ctx_reg(get_gpregs_ctx(cpu_ctx), CTX_GPREG_X3, x3);
+
+	/* Jump to the Secure Partition. */
+	rc = spm_sp_synchronous_entry(sp_ptr);
+
+	/* Flag Secure Partition as idle. */
+	assert(sp_ptr->state == SP_STATE_BUSY);
+	sp_state_set(sp_ptr, SP_STATE_IDLE);
+
+	return rc;
+}
+
+/*******************************************************************************
+ * MM_COMMUNICATE handler
+ ******************************************************************************/
+static uint64_t mm_communicate(uint32_t smc_fid, uint64_t mm_cookie,
+			       uint64_t comm_buffer_address,
+			       uint64_t comm_size_address, void *handle)
+{
+	uint64_t rc;
+
+	/* Cookie. Reserved for future use. It must be zero. */
+	if (mm_cookie != 0U) {
+		ERROR("MM_COMMUNICATE: cookie is not zero\n");
+		SMC_RET1(handle, SPM_MM_INVALID_PARAMETER);
+	}
+
+	if (comm_buffer_address == 0U) {
+		ERROR("MM_COMMUNICATE: comm_buffer_address is zero\n");
+		SMC_RET1(handle, SPM_MM_INVALID_PARAMETER);
+	}
+
+	if (comm_size_address != 0U) {
+		VERBOSE("MM_COMMUNICATE: comm_size_address is not 0 as recommended.\n");
+	}
+
+	/*
+	 * The current secure partition design mandates
+	 * - at any point, only a single core can be
+	 *   executing in the secure partiton.
+	 * - a core cannot be preempted by an interrupt
+	 *   while executing in secure partition.
+	 * Raise the running priority of the core to the
+	 * interrupt level configured for secure partition
+	 * so as to block any interrupt from preempting this
+	 * core.
+	 */
+	ehf_activate_priority(PLAT_SP_PRI);
+
+	/* Save the Normal world context */
+	cm_el1_sysregs_context_save(NON_SECURE);
+
+	rc = spm_mm_sp_call(smc_fid, comm_buffer_address, comm_size_address,
+			    plat_my_core_pos());
+
+	/* Restore non-secure state */
+	cm_el1_sysregs_context_restore(NON_SECURE);
+	cm_set_next_eret_context(NON_SECURE);
+
+	/*
+	 * Exited from secure partition. This core can take
+	 * interrupts now.
+	 */
+	ehf_deactivate_priority(PLAT_SP_PRI);
+
+	SMC_RET1(handle, rc);
+}
+
+/*******************************************************************************
+ * Secure Partition Manager SMC handler.
+ ******************************************************************************/
+uint64_t spm_mm_smc_handler(uint32_t smc_fid,
+			 uint64_t x1,
+			 uint64_t x2,
+			 uint64_t x3,
+			 uint64_t x4,
+			 void *cookie,
+			 void *handle,
+			 uint64_t flags)
+{
+	unsigned int ns;
+
+	/* Determine which security state this SMC originated from */
+	ns = is_caller_non_secure(flags);
+
+	if (ns == SMC_FROM_SECURE) {
+
+		/* Handle SMCs from Secure world. */
+
+		assert(handle == cm_get_context(SECURE));
+
+		/* Make next ERET jump to S-EL0 instead of S-EL1. */
+		cm_set_elr_spsr_el3(SECURE, read_elr_el1(), read_spsr_el1());
+
+		switch (smc_fid) {
+
+		case SPM_MM_VERSION_AARCH32:
+			SMC_RET1(handle, SPM_MM_VERSION_COMPILED);
+
+		case MM_SP_EVENT_COMPLETE_AARCH64:
+			spm_sp_synchronous_exit(x1);
+
+		case MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64:
+			INFO("Received MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64 SMC\n");
+
+			if (sp_ctx.state != SP_STATE_RESET) {
+				WARN("MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64 is available at boot time only\n");
+				SMC_RET1(handle, SPM_MM_NOT_SUPPORTED);
+			}
+			SMC_RET1(handle,
+				 spm_memory_attributes_get_smc_handler(
+					 &sp_ctx, x1));
+
+		case MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64:
+			INFO("Received MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64 SMC\n");
+
+			if (sp_ctx.state != SP_STATE_RESET) {
+				WARN("MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64 is available at boot time only\n");
+				SMC_RET1(handle, SPM_MM_NOT_SUPPORTED);
+			}
+			SMC_RET1(handle,
+				 spm_memory_attributes_set_smc_handler(
+					&sp_ctx, x1, x2, x3));
+		default:
+			break;
+		}
+	} else {
+
+		/* Handle SMCs from Non-secure world. */
+
+		assert(handle == cm_get_context(NON_SECURE));
+
+		switch (smc_fid) {
+
+		case MM_VERSION_AARCH32:
+			SMC_RET1(handle, MM_VERSION_COMPILED);
+
+		case MM_COMMUNICATE_AARCH32:
+		case MM_COMMUNICATE_AARCH64:
+			return mm_communicate(smc_fid, x1, x2, x3, handle);
+
+		case MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64:
+		case MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64:
+			/* SMC interfaces reserved for secure callers. */
+			SMC_RET1(handle, SPM_MM_NOT_SUPPORTED);
+
+		default:
+			break;
+		}
+	}
+
+	SMC_RET1(handle, SMC_UNK);
+}