services/std_svc/spmd/spmd_main.c

/*
 * Copyright (c) 2020, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <assert.h>
#include <errno.h>
#include <string.h>

#include <arch_helpers.h>
#include <arch/aarch64/arch_features.h>
#include <bl31/bl31.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 <plat/common/common_def.h>
#include <plat/common/platform.h>
#include <platform_def.h>
#include <services/ffa_svc.h>
#include <services/spmd_svc.h>
#include <smccc_helpers.h>
#include "spmd_private.h"

/*******************************************************************************
 * SPM Core context information.
 ******************************************************************************/
static spmd_spm_core_context_t spm_core_context[PLATFORM_CORE_COUNT];

/*******************************************************************************
 * SPM Core attribute information read from its manifest.
 ******************************************************************************/
static spmc_manifest_attribute_t spmc_attrs;

/*******************************************************************************
 * SPM Core entry point information. Discovered on the primary core and reused
 * on secondary cores.
 ******************************************************************************/
static entry_point_info_t *spmc_ep_info;

/*******************************************************************************
 * SPM Core context on current CPU get helper.
 ******************************************************************************/
spmd_spm_core_context_t *spmd_get_context(void)
{
	unsigned int linear_id = plat_my_core_pos();

	return &spm_core_context[linear_id];
}

/*******************************************************************************
 * Static function declaration.
 ******************************************************************************/
static int32_t spmd_init(void);
static int spmd_spmc_init(void *pm_addr);
static uint64_t spmd_ffa_error_return(void *handle,
				       int error_code);
static uint64_t spmd_smc_forward(uint32_t smc_fid,
				 bool secure_origin,
				 uint64_t x1,
				 uint64_t x2,
				 uint64_t x3,
				 uint64_t x4,
				 void *handle);

/*******************************************************************************
 * This function takes an SPMC context pointer and performs a synchronous
 * SPMC entry.
 ******************************************************************************/
uint64_t spmd_spm_core_sync_entry(spmd_spm_core_context_t *spmc_ctx)
{
	uint64_t rc;

	assert(spmc_ctx != NULL);

	cm_set_context(&(spmc_ctx->cpu_ctx), SECURE);

	/* Restore the context assigned above */
	cm_el1_sysregs_context_restore(SECURE);
#if SPMD_SPM_AT_SEL2
	cm_el2_sysregs_context_restore(SECURE);
#endif
	cm_set_next_eret_context(SECURE);

	/* Enter SPMC */
	rc = spmd_spm_core_enter(&spmc_ctx->c_rt_ctx);

	/* Save secure state */
	cm_el1_sysregs_context_save(SECURE);
#if SPMD_SPM_AT_SEL2
	cm_el2_sysregs_context_save(SECURE);
#endif

	return rc;
}

/*******************************************************************************
 * This function returns to the place where spmd_spm_core_sync_entry() was
 * called originally.
 ******************************************************************************/
__dead2 void spmd_spm_core_sync_exit(uint64_t rc)
{
	spmd_spm_core_context_t *ctx = spmd_get_context();

	/* Get current CPU context from SPMC context */
	assert(cm_get_context(SECURE) == &(ctx->cpu_ctx));

	/*
	 * The SPMD must have initiated the original request through a
	 * synchronous entry into SPMC. Jump back to the original C runtime
	 * context with the value of rc in x0;
	 */
	spmd_spm_core_exit(ctx->c_rt_ctx, rc);

	panic();
}

/*******************************************************************************
 * Jump to the SPM Core for the first time.
 ******************************************************************************/
static int32_t spmd_init(void)
{
	spmd_spm_core_context_t *ctx = spmd_get_context();
	uint64_t rc;

	VERBOSE("SPM Core init start.\n");
	ctx->state = SPMC_STATE_RESET;

	rc = spmd_spm_core_sync_entry(ctx);
	if (rc != 0ULL) {
		ERROR("SPMC initialisation failed 0x%llx\n", rc);
		return 0;
	}

	ctx->state = SPMC_STATE_IDLE;
	VERBOSE("SPM Core init end.\n");

	return 1;
}

/*******************************************************************************
 * Loads SPMC manifest and inits SPMC.
 ******************************************************************************/
static int spmd_spmc_init(void *pm_addr)
{
	spmd_spm_core_context_t *spm_ctx = spmd_get_context();
	uint32_t ep_attr;
	int rc;

	/* Load the SPM Core manifest */
	rc = plat_spm_core_manifest_load(&spmc_attrs, pm_addr);
	if (rc != 0) {
		WARN("No or invalid SPM Core manifest image provided by BL2\n");
		return rc;
	}

	/*
	 * Ensure that the SPM Core version is compatible with the SPM
	 * Dispatcher version.
	 */
	if ((spmc_attrs.major_version != FFA_VERSION_MAJOR) ||
	    (spmc_attrs.minor_version > FFA_VERSION_MINOR)) {
		WARN("Unsupported FFA version (%u.%u)\n",
		     spmc_attrs.major_version, spmc_attrs.minor_version);
		return -EINVAL;
	}

	VERBOSE("FFA version (%u.%u)\n", spmc_attrs.major_version,
	     spmc_attrs.minor_version);

	VERBOSE("SPM Core run time EL%x.\n",
	     SPMD_SPM_AT_SEL2 ? MODE_EL2 : MODE_EL1);

	/* Validate the SPMC ID, Ensure high bit is set */
	if (((spmc_attrs.spmc_id >> SPMC_SECURE_ID_SHIFT) &
			SPMC_SECURE_ID_MASK) == 0U) {
		WARN("Invalid ID (0x%x) for SPMC.\n", spmc_attrs.spmc_id);
		return -EINVAL;
	}

	/* Validate the SPM Core execution state */
	if ((spmc_attrs.exec_state != MODE_RW_64) &&
	    (spmc_attrs.exec_state != MODE_RW_32)) {
		WARN("Unsupported %s%x.\n", "SPM Core execution state 0x",
		     spmc_attrs.exec_state);
		return -EINVAL;
	}

	VERBOSE("%s%x.\n", "SPM Core execution state 0x",
		spmc_attrs.exec_state);

#if SPMD_SPM_AT_SEL2
	/* Ensure manifest has not requested AArch32 state in S-EL2 */
	if (spmc_attrs.exec_state == MODE_RW_32) {
		WARN("AArch32 state at S-EL2 is not supported.\n");
		return -EINVAL;
	}

	/*
	 * Check if S-EL2 is supported on this system if S-EL2
	 * is required for SPM
	 */
	if (!is_armv8_4_sel2_present()) {
		WARN("SPM Core run time S-EL2 is not supported.\n");
		return -EINVAL;
	}
#endif /* SPMD_SPM_AT_SEL2 */

	/* Initialise an entrypoint to set up the CPU context */
	ep_attr = SECURE | EP_ST_ENABLE;
	if ((read_sctlr_el3() & SCTLR_EE_BIT) != 0ULL) {
		ep_attr |= EP_EE_BIG;
	}

	SET_PARAM_HEAD(spmc_ep_info, PARAM_EP, VERSION_1, ep_attr);
	assert(spmc_ep_info->pc == BL32_BASE);

	/*
	 * Populate SPSR for SPM Core based upon validated parameters from the
	 * manifest.
	 */
	if (spmc_attrs.exec_state == MODE_RW_32) {
		spmc_ep_info->spsr = SPSR_MODE32(MODE32_svc, SPSR_T_ARM,
						 SPSR_E_LITTLE,
						 DAIF_FIQ_BIT |
						 DAIF_IRQ_BIT |
						 DAIF_ABT_BIT);
	} else {

#if SPMD_SPM_AT_SEL2
		static const uint32_t runtime_el = MODE_EL2;
#else
		static const uint32_t runtime_el = MODE_EL1;
#endif
		spmc_ep_info->spsr = SPSR_64(runtime_el,
					     MODE_SP_ELX,
					     DISABLE_ALL_EXCEPTIONS);
	}

	/* Initialise SPM Core context with this entry point information */
	cm_setup_context(&spm_ctx->cpu_ctx, spmc_ep_info);

	/* Reuse PSCI affinity states to mark this SPMC context as off */
	spm_ctx->state = AFF_STATE_OFF;

	INFO("SPM Core setup done.\n");

	/* Register init function for deferred init. */
	bl31_register_bl32_init(&spmd_init);

	return 0;
}

/*******************************************************************************
 * Initialize context of SPM Core.
 ******************************************************************************/
int spmd_setup(void)
{
	void *spmc_manifest;
	int rc;

	spmc_ep_info = bl31_plat_get_next_image_ep_info(SECURE);
	if (spmc_ep_info == NULL) {
		WARN("No SPM Core image provided by BL2 boot loader.\n");
		return -EINVAL;
	}

	/* Under no circumstances will this parameter be 0 */
	assert(spmc_ep_info->pc != 0ULL);

	/*
	 * Check if BL32 ep_info has a reference to 'tos_fw_config'. This will
	 * be used as a manifest for the SPM Core at the next lower EL/mode.
	 */
	spmc_manifest = (void *)spmc_ep_info->args.arg0;
	if (spmc_manifest == NULL) {
		ERROR("Invalid or absent SPM Core manifest.\n");
		return -EINVAL;
	}

	/* Load manifest, init SPMC */
	rc = spmd_spmc_init(spmc_manifest);
	if (rc != 0) {
		WARN("Booting device without SPM initialization.\n");
	}

	return rc;
}

/*******************************************************************************
 * Forward SMC to the other security state
 ******************************************************************************/
static uint64_t spmd_smc_forward(uint32_t smc_fid,
				 bool secure_origin,
				 uint64_t x1,
				 uint64_t x2,
				 uint64_t x3,
				 uint64_t x4,
				 void *handle)
{
	uint32_t secure_state_in = (secure_origin) ? SECURE : NON_SECURE;
	uint32_t secure_state_out = (!secure_origin) ? SECURE : NON_SECURE;

	/* Save incoming security state */
	cm_el1_sysregs_context_save(secure_state_in);
#if SPMD_SPM_AT_SEL2
	cm_el2_sysregs_context_save(secure_state_in);
#endif

	/* Restore outgoing security state */
	cm_el1_sysregs_context_restore(secure_state_out);
#if SPMD_SPM_AT_SEL2
	cm_el2_sysregs_context_restore(secure_state_out);
#endif
	cm_set_next_eret_context(secure_state_out);

	SMC_RET8(cm_get_context(secure_state_out), smc_fid, x1, x2, x3, x4,
			SMC_GET_GP(handle, CTX_GPREG_X5),
			SMC_GET_GP(handle, CTX_GPREG_X6),
			SMC_GET_GP(handle, CTX_GPREG_X7));
}

/*******************************************************************************
 * Return FFA_ERROR with specified error code
 ******************************************************************************/
static uint64_t spmd_ffa_error_return(void *handle, int error_code)
{
	SMC_RET8(handle, FFA_ERROR,
		 FFA_TARGET_INFO_MBZ, error_code,
		 FFA_PARAM_MBZ, FFA_PARAM_MBZ, FFA_PARAM_MBZ,
		 FFA_PARAM_MBZ, FFA_PARAM_MBZ);
}

/*******************************************************************************
 * This function handles all SMCs in the range reserved for FFA. Each call is
 * either forwarded to the other security state or handled by the SPM dispatcher
 ******************************************************************************/
uint64_t spmd_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)
{
	spmd_spm_core_context_t *ctx = spmd_get_context();
	bool secure_origin;
	int32_t ret;

	/* Determine which security state this SMC originated from */
	secure_origin = is_caller_secure(flags);

	INFO("SPM: 0x%x 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx\n",
	     smc_fid, x1, x2, x3, x4, SMC_GET_GP(handle, CTX_GPREG_X5),
	     SMC_GET_GP(handle, CTX_GPREG_X6),
	     SMC_GET_GP(handle, CTX_GPREG_X7));

	switch (smc_fid) {
	case FFA_ERROR:
		/*
		 * Check if this is the first invocation of this interface on
		 * this CPU. If so, then indicate that the SPM Core initialised
		 * unsuccessfully.
		 */
		if (secure_origin && (ctx->state == SPMC_STATE_RESET)) {
			spmd_spm_core_sync_exit(x2);
		}

		return spmd_smc_forward(smc_fid, secure_origin,
					x1, x2, x3, x4, handle);
		break; /* not reached */

	case FFA_VERSION:
		/*
		 * TODO: This is an optimization that the version information
		 * provided by the SPM Core manifest is returned by the SPM
		 * dispatcher. It might be a better idea to simply forward this
		 * call to the SPM Core and wash our hands completely.
		 */
		ret = MAKE_FFA_VERSION(spmc_attrs.major_version,
					spmc_attrs.minor_version);
		SMC_RET8(handle, FFA_SUCCESS_SMC32, FFA_TARGET_INFO_MBZ, ret,
			 FFA_PARAM_MBZ, FFA_PARAM_MBZ, FFA_PARAM_MBZ,
			 FFA_PARAM_MBZ, FFA_PARAM_MBZ);
		break; /* not reached */

	case FFA_FEATURES:
		/*
		 * This is an optional interface. Do the minimal checks and
		 * forward to SPM Core which will handle it if implemented.
		 */

		/*
		 * Check if x1 holds a valid FFA fid. This is an
		 * optimization.
		 */
		if (!is_ffa_fid(x1)) {
			return spmd_ffa_error_return(handle,
						      FFA_ERROR_NOT_SUPPORTED);
		}

		/* Forward SMC from Normal world to the SPM Core */
		if (!secure_origin) {
			return spmd_smc_forward(smc_fid, secure_origin,
						x1, x2, x3, x4, handle);
		}

		/*
		 * Return success if call was from secure world i.e. all
		 * FFA functions are supported. This is essentially a
		 * nop.
		 */
		SMC_RET8(handle, FFA_SUCCESS_SMC32, x1, x2, x3, x4,
			 SMC_GET_GP(handle, CTX_GPREG_X5),
			 SMC_GET_GP(handle, CTX_GPREG_X6),
			 SMC_GET_GP(handle, CTX_GPREG_X7));

		break; /* not reached */

	case FFA_ID_GET:
		/*
		 * Returns the ID of the calling FFA component.
		 */
		if (!secure_origin) {
			SMC_RET8(handle, FFA_SUCCESS_SMC32,
				 FFA_TARGET_INFO_MBZ, FFA_NS_ENDPOINT_ID,
				 FFA_PARAM_MBZ, FFA_PARAM_MBZ,
				 FFA_PARAM_MBZ, FFA_PARAM_MBZ,
				 FFA_PARAM_MBZ);
		}

		SMC_RET8(handle, FFA_SUCCESS_SMC32,
			 FFA_TARGET_INFO_MBZ, spmc_attrs.spmc_id,
			 FFA_PARAM_MBZ, FFA_PARAM_MBZ,
			 FFA_PARAM_MBZ, FFA_PARAM_MBZ,
			 FFA_PARAM_MBZ);

		break; /* not reached */

	case FFA_RX_RELEASE:
	case FFA_RXTX_MAP_SMC32:
	case FFA_RXTX_MAP_SMC64:
	case FFA_RXTX_UNMAP:
	case FFA_MSG_RUN:
		/* This interface must be invoked only by the Normal world */
		if (secure_origin) {
			return spmd_ffa_error_return(handle,
						      FFA_ERROR_NOT_SUPPORTED);
		}

		/* Fall through to forward the call to the other world */

	case FFA_PARTITION_INFO_GET:
	case FFA_MSG_SEND:
	case FFA_MSG_SEND_DIRECT_REQ_SMC32:
	case FFA_MSG_SEND_DIRECT_REQ_SMC64:
	case FFA_MSG_SEND_DIRECT_RESP_SMC32:
	case FFA_MSG_SEND_DIRECT_RESP_SMC64:
	case FFA_MEM_DONATE_SMC32:
	case FFA_MEM_DONATE_SMC64:
	case FFA_MEM_LEND_SMC32:
	case FFA_MEM_LEND_SMC64:
	case FFA_MEM_SHARE_SMC32:
	case FFA_MEM_SHARE_SMC64:
	case FFA_MEM_RETRIEVE_REQ_SMC32:
	case FFA_MEM_RETRIEVE_REQ_SMC64:
	case FFA_MEM_RETRIEVE_RESP:
	case FFA_MEM_RELINQUISH:
	case FFA_MEM_RECLAIM:
	case FFA_SUCCESS_SMC32:
	case FFA_SUCCESS_SMC64:
		/*
		 * TODO: Assume that no requests originate from EL3 at the
		 * moment. This will change if a SP service is required in
		 * response to secure interrupts targeted to EL3. Until then
		 * simply forward the call to the Normal world.
		 */

		return spmd_smc_forward(smc_fid, secure_origin,
					x1, x2, x3, x4, handle);
		break; /* not reached */

	case FFA_MSG_WAIT:
		/*
		 * Check if this is the first invocation of this interface on
		 * this CPU from the Secure world. If so, then indicate that the
		 * SPM Core initialised successfully.
		 */
		if (secure_origin && (ctx->state == SPMC_STATE_RESET)) {
			spmd_spm_core_sync_exit(0);
		}

		/* Fall through to forward the call to the other world */

	case FFA_MSG_YIELD:
		/* This interface must be invoked only by the Secure world */
		if (!secure_origin) {
			return spmd_ffa_error_return(handle,
						      FFA_ERROR_NOT_SUPPORTED);
		}

		return spmd_smc_forward(smc_fid, secure_origin,
					x1, x2, x3, x4, handle);
		break; /* not reached */

	default:
		WARN("SPM: Unsupported call 0x%08x\n", smc_fid);
		return spmd_ffa_error_return(handle, FFA_ERROR_NOT_SUPPORTED);
	}
}