services/std_svc/drtm/drtm_main.c

/*
 * Copyright (c) 2022 Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier:    BSD-3-Clause
 *
 * DRTM service
 *
 * Authors:
 *	Lucian Paul-Trifu <lucian.paultrifu@gmail.com>
 *	Brian Nezvadovitz <brinez@microsoft.com> 2021-02-01
 */

#include <stdint.h>

#include <arch.h>
#include <arch_helpers.h>
#include <common/bl_common.h>
#include <common/debug.h>
#include <common/runtime_svc.h>
#include <drivers/auth/crypto_mod.h>
#include "drtm_main.h"
#include <lib/psci/psci_lib.h>
#include <lib/xlat_tables/xlat_tables_v2.h>
#include <plat/common/platform.h>
#include <services/drtm_svc.h>
#include <platform_def.h>

/* Structure to store DRTM features specific to the platform. */
static drtm_features_t plat_drtm_features;

/* DRTM-formatted memory map. */
static drtm_memory_region_descriptor_table_t *plat_drtm_mem_map;

int drtm_setup(void)
{
	bool rc;
	const plat_drtm_tpm_features_t *plat_tpm_feat;
	const plat_drtm_dma_prot_features_t *plat_dma_prot_feat;
	uint64_t dlme_data_min_size;

	INFO("DRTM service setup\n");

	/* Read boot PE ID from MPIDR */
	plat_drtm_features.boot_pe_id = read_mpidr_el1() & MPIDR_AFFINITY_MASK;

	rc = drtm_dma_prot_init();
	if (rc) {
		return INTERNAL_ERROR;
	}

	/*
	 * initialise the platform supported crypto module that will
	 * be used by the DRTM-service to calculate hash of DRTM-
	 * implementation specific components
	 */
	crypto_mod_init();

	/* Build DRTM-compatible address map. */
	plat_drtm_mem_map = drtm_build_address_map();
	if (plat_drtm_mem_map == NULL) {
		return INTERNAL_ERROR;
	}

	/* Get DRTM features from platform hooks. */
	plat_tpm_feat = plat_drtm_get_tpm_features();
	if (plat_tpm_feat == NULL) {
		return INTERNAL_ERROR;
	}

	plat_dma_prot_feat = plat_drtm_get_dma_prot_features();
	if (plat_dma_prot_feat == NULL) {
		return INTERNAL_ERROR;
	}

	/*
	 * Add up minimum DLME data memory.
	 *
	 * For systems with complete DMA protection there is only one entry in
	 * the protected regions table.
	 */
	if (plat_dma_prot_feat->dma_protection_support ==
			ARM_DRTM_DMA_PROT_FEATURES_DMA_SUPPORT_COMPLETE) {
		dlme_data_min_size =
			sizeof(drtm_memory_region_descriptor_table_t) +
			sizeof(drtm_mem_region_t);
	} else {
		/*
		 * TODO set protected regions table size based on platform DMA
		 * protection configuration
		 */
		panic();
	}

	dlme_data_min_size += (drtm_get_address_map_size() +
			       PLAT_DRTM_EVENT_LOG_MAX_SIZE +
			       plat_drtm_get_tcb_hash_table_size() +
			       plat_drtm_get_imp_def_dlme_region_size());

	dlme_data_min_size = page_align(dlme_data_min_size, UP)/PAGE_SIZE;

	/* Fill out platform DRTM features structure */
	/* Only support default PCR schema (0x1) in this implementation. */
	ARM_DRTM_TPM_FEATURES_SET_PCR_SCHEMA(plat_drtm_features.tpm_features,
		ARM_DRTM_TPM_FEATURES_PCR_SCHEMA_DEFAULT);
	ARM_DRTM_TPM_FEATURES_SET_TPM_HASH(plat_drtm_features.tpm_features,
		plat_tpm_feat->tpm_based_hash_support);
	ARM_DRTM_TPM_FEATURES_SET_FW_HASH(plat_drtm_features.tpm_features,
		plat_tpm_feat->firmware_hash_algorithm);
	ARM_DRTM_MIN_MEM_REQ_SET_MIN_DLME_DATA_SIZE(plat_drtm_features.minimum_memory_requirement,
		dlme_data_min_size);
	ARM_DRTM_MIN_MEM_REQ_SET_DCE_SIZE(plat_drtm_features.minimum_memory_requirement,
		plat_drtm_get_min_size_normal_world_dce());
	ARM_DRTM_DMA_PROT_FEATURES_SET_MAX_REGIONS(plat_drtm_features.dma_prot_features,
		plat_dma_prot_feat->max_num_mem_prot_regions);
	ARM_DRTM_DMA_PROT_FEATURES_SET_DMA_SUPPORT(plat_drtm_features.dma_prot_features,
		plat_dma_prot_feat->dma_protection_support);
	ARM_DRTM_TCB_HASH_FEATURES_SET_MAX_NUM_HASHES(plat_drtm_features.tcb_hash_features,
		plat_drtm_get_tcb_hash_features());

	return 0;
}

static inline uint64_t drtm_features_tpm(void *ctx)
{
	SMC_RET2(ctx, 1ULL, /* TPM feature is supported */
		 plat_drtm_features.tpm_features);
}

static inline uint64_t drtm_features_mem_req(void *ctx)
{
	SMC_RET2(ctx, 1ULL, /* memory req Feature is supported */
		 plat_drtm_features.minimum_memory_requirement);
}

static inline uint64_t drtm_features_boot_pe_id(void *ctx)
{
	SMC_RET2(ctx, 1ULL, /* Boot PE feature is supported */
		 plat_drtm_features.boot_pe_id);
}

static inline uint64_t drtm_features_dma_prot(void *ctx)
{
	SMC_RET2(ctx, 1ULL, /* DMA protection feature is supported */
		 plat_drtm_features.dma_prot_features);
}

static inline uint64_t drtm_features_tcb_hashes(void *ctx)
{
	SMC_RET2(ctx, 1ULL, /* TCB hash feature is supported */
		 plat_drtm_features.tcb_hash_features);
}

static enum drtm_retc drtm_dl_check_caller_el(void *ctx)
{
	uint64_t spsr_el3 = read_ctx_reg(get_el3state_ctx(ctx), CTX_SPSR_EL3);
	uint64_t dl_caller_el;
	uint64_t dl_caller_aarch;

	dl_caller_el = spsr_el3 >> MODE_EL_SHIFT & MODE_EL_MASK;
	dl_caller_aarch = spsr_el3 >> MODE_RW_SHIFT & MODE_RW_MASK;

	/* Caller's security state is checked from drtm_smc_handle function */

	/* Caller can be NS-EL2/EL1 */
	if (dl_caller_el == MODE_EL3) {
		ERROR("DRTM: invalid launch from EL3\n");
		return DENIED;
	}

	if (dl_caller_aarch != MODE_RW_64) {
		ERROR("DRTM: invalid launch from non-AArch64 execution state\n");
		return DENIED;
	}

	return SUCCESS;
}

static enum drtm_retc drtm_dl_check_cores(void)
{
	bool running_on_single_core;
	uint64_t this_pe_aff_value = read_mpidr_el1() & MPIDR_AFFINITY_MASK;

	if (this_pe_aff_value != plat_drtm_features.boot_pe_id) {
		ERROR("DRTM: invalid launch on a non-boot PE\n");
		return DENIED;
	}

	running_on_single_core = psci_is_last_on_cpu_safe();
	if (!running_on_single_core) {
		ERROR("DRTM: invalid launch due to non-boot PE not being turned off\n");
		return DENIED;
	}

	return SUCCESS;
}

static uint64_t drtm_dynamic_launch(uint64_t x1, void *handle)
{
	enum drtm_retc ret = SUCCESS;

	/* Ensure that only boot PE is powered on */
	ret = drtm_dl_check_cores();
	if (ret != SUCCESS) {
		SMC_RET1(handle, ret);
	}

	/*
	 * Ensure that execution state is AArch64 and the caller
	 * is highest non-secure exception level
	 */
	ret = drtm_dl_check_caller_el(handle);
	if (ret != SUCCESS) {
		SMC_RET1(handle, ret);
	}

	SMC_RET1(handle, ret);
}

uint64_t drtm_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)
{
	/* Check that the SMC call is from the Normal World. */
	if (!is_caller_non_secure(flags)) {
		SMC_RET1(handle, NOT_SUPPORTED);
	}

	switch (smc_fid) {
	case ARM_DRTM_SVC_VERSION:
		INFO("DRTM service handler: version\n");
		/* Return the version of current implementation */
		SMC_RET1(handle, ARM_DRTM_VERSION);
		break;	/* not reached */

	case ARM_DRTM_SVC_FEATURES:
		if (((x1 >> ARM_DRTM_FUNC_SHIFT) & ARM_DRTM_FUNC_MASK) ==
		    ARM_DRTM_FUNC_ID) {
			/* Dispatch function-based queries. */
			switch (x1 & FUNCID_MASK) {
			case ARM_DRTM_SVC_VERSION:
				SMC_RET1(handle, SUCCESS);
				break;	/* not reached */

			case ARM_DRTM_SVC_FEATURES:
				SMC_RET1(handle, SUCCESS);
				break;	/* not reached */

			case ARM_DRTM_SVC_UNPROTECT_MEM:
				SMC_RET1(handle, SUCCESS);
				break;	/* not reached */

			case ARM_DRTM_SVC_DYNAMIC_LAUNCH:
				SMC_RET1(handle, SUCCESS);
				break;	/* not reached */

			case ARM_DRTM_SVC_CLOSE_LOCALITY:
				WARN("ARM_DRTM_SVC_CLOSE_LOCALITY feature %s",
				     "is not supported\n");
				SMC_RET1(handle, NOT_SUPPORTED);
				break;	/* not reached */

			case ARM_DRTM_SVC_GET_ERROR:
				SMC_RET1(handle, SUCCESS);
				break;	/* not reached */

			case ARM_DRTM_SVC_SET_ERROR:
				SMC_RET1(handle, SUCCESS);
				break;	/* not reached */

			case ARM_DRTM_SVC_SET_TCB_HASH:
				WARN("ARM_DRTM_SVC_TCB_HASH feature %s",
				     "is not supported\n");
				SMC_RET1(handle, NOT_SUPPORTED);
				break;	/* not reached */

			case ARM_DRTM_SVC_LOCK_TCB_HASH:
				WARN("ARM_DRTM_SVC_LOCK_TCB_HASH feature %s",
				     "is not supported\n");
				SMC_RET1(handle, NOT_SUPPORTED);
				break;	/* not reached */

			default:
				ERROR("Unknown DRTM service function\n");
				SMC_RET1(handle, NOT_SUPPORTED);
				break;	/* not reached */
			}
		} else {
			/* Dispatch feature-based queries. */
			switch (x1 & ARM_DRTM_FEAT_ID_MASK) {
			case ARM_DRTM_FEATURES_TPM:
				INFO("++ DRTM service handler: TPM features\n");
				return drtm_features_tpm(handle);
				break;	/* not reached */

			case ARM_DRTM_FEATURES_MEM_REQ:
				INFO("++ DRTM service handler: Min. mem."
				     " requirement features\n");
				return drtm_features_mem_req(handle);
				break;	/* not reached */

			case ARM_DRTM_FEATURES_DMA_PROT:
				INFO("++ DRTM service handler: "
				     "DMA protection features\n");
				return drtm_features_dma_prot(handle);
				break;	/* not reached */

			case ARM_DRTM_FEATURES_BOOT_PE_ID:
				INFO("++ DRTM service handler: "
				     "Boot PE ID features\n");
				return drtm_features_boot_pe_id(handle);
				break;	/* not reached */

			case ARM_DRTM_FEATURES_TCB_HASHES:
				INFO("++ DRTM service handler: "
				     "TCB-hashes features\n");
				return drtm_features_tcb_hashes(handle);
				break;	/* not reached */

			default:
				ERROR("Unknown ARM DRTM service feature\n");
				SMC_RET1(handle, NOT_SUPPORTED);
				break;	/* not reached */
			}
		}

	case ARM_DRTM_SVC_UNPROTECT_MEM:
		INFO("DRTM service handler: unprotect mem\n");
		SMC_RET1(handle, SMC_OK);
		break;	/* not reached */

	case ARM_DRTM_SVC_DYNAMIC_LAUNCH:
		INFO("DRTM service handler: dynamic launch\n");
		return drtm_dynamic_launch(x1, handle);
		break;	/* not reached */

	case ARM_DRTM_SVC_CLOSE_LOCALITY:
		WARN("DRTM service handler: close locality %s\n",
		     "is not supported");
		SMC_RET1(handle, NOT_SUPPORTED);
		break;	/* not reached */

	case ARM_DRTM_SVC_GET_ERROR:
		INFO("DRTM service handler: get error\n");
		SMC_RET2(handle, SMC_OK, 0);
		break;	/* not reached */

	case ARM_DRTM_SVC_SET_ERROR:
		INFO("DRTM service handler: set error\n");
		SMC_RET1(handle, SMC_OK);
		break;	/* not reached */

	case ARM_DRTM_SVC_SET_TCB_HASH:
		WARN("DRTM service handler: set TCB hash %s\n",
		     "is not supported");
		SMC_RET1(handle, NOT_SUPPORTED);
		break;  /* not reached */

	case ARM_DRTM_SVC_LOCK_TCB_HASH:
		WARN("DRTM service handler: lock TCB hash %s\n",
		     "is not supported");
		SMC_RET1(handle, NOT_SUPPORTED);
		break;  /* not reached */

	default:
		ERROR("Unknown DRTM service function: 0x%x\n", smc_fid);
		SMC_RET1(handle, SMC_UNK);
		break;	/* not reached */
	}

	/* not reached */
	SMC_RET1(handle, SMC_UNK);
}