secure_fw/spm/cmsis_psa/spm_ipc.c

/*
 * Copyright (c) 2018-2021, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *
 */

#include <inttypes.h>
#include <stdbool.h>
#include "bitops.h"
#include "critical_section.h"
#include "current.h"
#include "fih.h"
#include "psa/client.h"
#include "psa/service.h"
#include "thread.h"
#include "internal_errors.h"
#include "tfm_spm_hal.h"
#include "tfm_api.h"
#include "tfm_secure_api.h"
#include "tfm_memory_utils.h"
#include "tfm_hal_defs.h"
#include "tfm_hal_interrupt.h"
#include "tfm_hal_isolation.h"
#include "spm_ipc.h"
#include "tfm_peripherals_def.h"
#include "tfm_core_utils.h"
#include "tfm_nspm.h"
#include "tfm_rpc.h"
#include "tfm_core_trustzone.h"
#include "lists.h"
#include "tfm_pools.h"
#include "region.h"
#include "psa_manifest/pid.h"
#include "ffm/backend.h"
#include "load/partition_defs.h"
#include "load/service_defs.h"
#include "load/asset_defs.h"
#include "load/spm_load_api.h"
#include "tfm_nspm.h"

/* Partition and service runtime data list head/runtime data table */
static struct service_head_t services_listhead;
struct service_t *stateless_services_ref_tbl[STATIC_HANDLE_NUM_LIMIT];

/* Pools */
TFM_POOL_DECLARE(conn_handle_pool, sizeof(struct tfm_conn_handle_t),
                 TFM_CONN_HANDLE_MAX_NUM);

/*********************** Connection handle conversion APIs *******************/

#define CONVERSION_FACTOR_BITOFFSET    3
#define CONVERSION_FACTOR_VALUE        (1 << CONVERSION_FACTOR_BITOFFSET)
/* Set 32 as the maximum */
#define CONVERSION_FACTOR_VALUE_MAX    0x20

#if CONVERSION_FACTOR_VALUE > CONVERSION_FACTOR_VALUE_MAX
#error "CONVERSION FACTOR OUT OF RANGE"
#endif

static uint32_t loop_index;

/*
 * A handle instance psa_handle_t allocated inside SPM is actually a memory
 * address among the handle pool. Return this handle to the client directly
 * exposes information of secure memory address. In this case, converting the
 * handle into another value does not represent the memory address to avoid
 * exposing secure memory directly to clients.
 *
 * This function converts the handle instance into another value by scaling the
 * handle in pool offset, the converted value is named as a user handle.
 *
 * The formula:
 *  user_handle = (handle_instance - POOL_START) * CONVERSION_FACTOR_VALUE +
 *                CLIENT_HANDLE_VALUE_MIN + loop_index
 * where:
 *  CONVERSION_FACTOR_VALUE = 1 << CONVERSION_FACTOR_BITOFFSET, and should not
 *  exceed CONVERSION_FACTOR_VALUE_MAX.
 *
 *  handle_instance in RANGE[POOL_START, POOL_END]
 *  user_handle     in RANGE[CLIENT_HANDLE_VALUE_MIN, 0x3FFFFFFF]
 *  loop_index      in RANGE[0, CONVERSION_FACTOR_VALUE - 1]
 *
 *  note:
 *  loop_index is used to promise same handle instance is converted into
 *  different user handles in short time.
 */
psa_handle_t tfm_spm_to_user_handle(struct tfm_conn_handle_t *handle_instance)
{
    psa_handle_t user_handle;

    loop_index = (loop_index + 1) % CONVERSION_FACTOR_VALUE;
    user_handle = (psa_handle_t)((((uintptr_t)handle_instance -
                  (uintptr_t)conn_handle_pool) << CONVERSION_FACTOR_BITOFFSET) +
                  CLIENT_HANDLE_VALUE_MIN + loop_index);

    return user_handle;
}

/*
 * This function converts a user handle into a corresponded handle instance.
 * The converted value is validated before returning, an invalid handle instance
 * is returned as NULL.
 *
 * The formula:
 *  handle_instance = ((user_handle - CLIENT_HANDLE_VALUE_MIN) /
 *                    CONVERSION_FACTOR_VALUE) + POOL_START
 * where:
 *  CONVERSION_FACTOR_VALUE = 1 << CONVERSION_FACTOR_BITOFFSET, and should not
 *  exceed CONVERSION_FACTOR_VALUE_MAX.
 *
 *  handle_instance in RANGE[POOL_START, POOL_END]
 *  user_handle     in RANGE[CLIENT_HANDLE_VALUE_MIN, 0x3FFFFFFF]
 *  loop_index      in RANGE[0, CONVERSION_FACTOR_VALUE - 1]
 */
struct tfm_conn_handle_t *tfm_spm_to_handle_instance(psa_handle_t user_handle)
{
    struct tfm_conn_handle_t *handle_instance;

    if (user_handle == PSA_NULL_HANDLE) {
        return NULL;
    }

    handle_instance = (struct tfm_conn_handle_t *)((((uintptr_t)user_handle -
                      CLIENT_HANDLE_VALUE_MIN) >> CONVERSION_FACTOR_BITOFFSET) +
                      (uintptr_t)conn_handle_pool);

    return handle_instance;
}

/* Service handle management functions */
struct tfm_conn_handle_t *tfm_spm_create_conn_handle(struct service_t *service,
                                                     int32_t client_id)
{
    struct tfm_conn_handle_t *p_handle;

    TFM_CORE_ASSERT(service);

    /* Get buffer for handle list structure from handle pool */
    p_handle = (struct tfm_conn_handle_t *)tfm_pool_alloc(conn_handle_pool);
    if (!p_handle) {
        return NULL;
    }

    p_handle->internal_msg.service = service;
    p_handle->status = TFM_HANDLE_STATUS_IDLE;
    p_handle->client_id = client_id;

    /* Add handle node to list for next psa functions */
    BI_LIST_INSERT_BEFORE(&service->handle_list, &p_handle->list);

    return p_handle;
}

int32_t tfm_spm_validate_conn_handle(
                                    const struct tfm_conn_handle_t *conn_handle,
                                    int32_t client_id)
{
    /* Check the handle address is validated */
    if (is_valid_chunk_data_in_pool(conn_handle_pool,
                                    (uint8_t *)conn_handle) != true) {
        return SPM_ERROR_GENERIC;
    }

    /* Check the handle caller is correct */
    if (conn_handle->client_id != client_id) {
        return SPM_ERROR_GENERIC;
    }

    return SPM_SUCCESS;
}

int32_t tfm_spm_free_conn_handle(struct service_t *service,
                                 struct tfm_conn_handle_t *conn_handle)
{
    TFM_CORE_ASSERT(service);
    TFM_CORE_ASSERT(conn_handle != NULL);

    /* Clear magic as the handler is not used anymore */
    conn_handle->internal_msg.magic = 0;

    /* Remove node from handle list */
    BI_LIST_REMOVE_NODE(&conn_handle->list);

    /* Back handle buffer to pool */
    tfm_pool_free(conn_handle_pool, conn_handle);
    return SPM_SUCCESS;
}

int32_t tfm_spm_set_rhandle(struct service_t *service,
                            struct tfm_conn_handle_t *conn_handle,
                            void *rhandle)
{
    TFM_CORE_ASSERT(service);
    /* Set reverse handle value only be allowed for a connected handle */
    TFM_CORE_ASSERT(conn_handle != NULL);

    conn_handle->rhandle = rhandle;
    return SPM_SUCCESS;
}

/**
 * \brief                   Get reverse handle value from connection handle.
 *
 * \param[in] service       Target service context pointer
 * \param[in] conn_handle   Connection handle created by
 *                          tfm_spm_create_conn_handle()
 *
 * \retval void *           Success
 * \retval "Does not return"  Panic for those:
 *                              service pointer are NULL
 *                              handle is \ref PSA_NULL_HANDLE
 *                              handle node does not be found
 */
static void *tfm_spm_get_rhandle(struct service_t *service,
                                 struct tfm_conn_handle_t *conn_handle)
{
    TFM_CORE_ASSERT(service);
    /* Get reverse handle value only be allowed for a connected handle */
    TFM_CORE_ASSERT(conn_handle != NULL);

    return conn_handle->rhandle;
}

/* Partition management functions */

struct tfm_msg_body_t *tfm_spm_get_msg_by_signal(struct partition_t *partition,
                                                 psa_signal_t signal)
{
    struct bi_list_node_t *node, *head;
    struct tfm_msg_body_t *tmp_msg, *msg = NULL;
    struct critical_section_t cs_assert = CRITICAL_SECTION_STATIC_INIT;

    TFM_CORE_ASSERT(partition);

    head = &partition->msg_list;

    if (BI_LIST_IS_EMPTY(head)) {
        return NULL;
    }

    /*
     * There may be multiple messages for this RoT Service signal, do not clear
     * partition mask until no remaining message. Search may be optimized.
     */
    BI_LIST_FOR_EACH(node, head) {
        tmp_msg = TO_CONTAINER(node, struct tfm_msg_body_t, msg_node);
        if (tmp_msg->service->p_ldinf->signal == signal && msg) {
            return msg;
        } else if (tmp_msg->service->p_ldinf->signal == signal) {
            msg = tmp_msg;
            BI_LIST_REMOVE_NODE(node);
        }
    }

    CRITICAL_SECTION_ENTER(cs_assert);
    partition->signals_asserted &= ~signal;
    CRITICAL_SECTION_LEAVE(cs_assert);

    return msg;
}

uint32_t tfm_spm_partition_get_privileged_mode(uint32_t partition_flags)
{
#if TFM_LVL == 1
    return TFM_PARTITION_PRIVILEGED_MODE;
#else /* TFM_LVL == 1 */
    if (partition_flags & PARTITION_MODEL_PSA_ROT) {
        return TFM_PARTITION_PRIVILEGED_MODE;
    } else {
        return TFM_PARTITION_UNPRIVILEGED_MODE;
    }
#endif /* TFM_LVL == 1 */
}

struct service_t *tfm_spm_get_service_by_sid(uint32_t sid)
{
    struct service_t *p_prev, *p_curr;

    UNI_LIST_FOR_EACH_PREV(p_prev, p_curr, &services_listhead) {
        if (p_curr->p_ldinf->sid == sid) {
            UNI_LIST_MOVE_AFTER(&services_listhead, p_prev, p_curr);
            return p_curr;
        }
    }

    return NULL;
}

/**
 * \brief                   Get the partition context by partition ID.
 *
 * \param[in] partition_id  Partition identity
 *
 * \retval NULL             Failed
 * \retval "Not NULL"       Target partition context pointer,
 *                          \ref partition_t structures
 */
struct partition_t *tfm_spm_get_partition_by_id(int32_t partition_id)
{
    struct partition_t *p_part;

    UNI_LIST_FOR_EACH(p_part, PARTITION_LIST_ADDR) {
        if (p_part->p_ldinf->pid == partition_id) {
            return p_part;
        }
    }

    return NULL;
}

struct partition_t *tfm_spm_get_running_partition(void)
{
    return GET_CURRENT_COMPONENT();
}

int32_t tfm_spm_check_client_version(struct service_t *service,
                                     uint32_t version)
{
    TFM_CORE_ASSERT(service);

    switch (SERVICE_GET_VERSION_POLICY(service->p_ldinf->flags)) {
    case SERVICE_VERSION_POLICY_RELAXED:
        if (version > service->p_ldinf->version) {
            return SPM_ERROR_VERSION;
        }
        break;
    case SERVICE_VERSION_POLICY_STRICT:
        if (version != service->p_ldinf->version) {
            return SPM_ERROR_VERSION;
        }
        break;
    default:
        return SPM_ERROR_VERSION;
    }
    return SPM_SUCCESS;
}

int32_t tfm_spm_check_authorization(uint32_t sid,
                                    struct service_t *service,
                                    bool ns_caller)
{
    struct partition_t *partition = NULL;
    uint32_t *dep;
    int32_t i;

    TFM_CORE_ASSERT(service);

    if (ns_caller) {
        if (!SERVICE_IS_NS_ACCESSIBLE(service->p_ldinf->flags)) {
            return SPM_ERROR_GENERIC;
        }
    } else {
        partition = tfm_spm_get_running_partition();
        if (!partition) {
            tfm_core_panic();
        }

        dep = (uint32_t *)LOAD_INFO_DEPS(partition->p_ldinf);
        for (i = 0; i < partition->p_ldinf->ndeps; i++) {
            if (dep[i] == sid) {
                break;
            }
        }

        if (i == partition->p_ldinf->ndeps) {
            return SPM_ERROR_GENERIC;
        }
    }
    return SPM_SUCCESS;
}

/* Message functions */

struct tfm_msg_body_t *tfm_spm_get_msg_from_handle(psa_handle_t msg_handle)
{
    /*
     * The message handler passed by the caller is considered invalid in the
     * following cases:
     *   1. Not a valid message handle. (The address of a message is not the
     *      address of a possible handle from the pool
     *   2. Handle not belongs to the caller partition (The handle is either
     *      unused, or owned by anither partition)
     * Check the conditions above
     */
    struct tfm_msg_body_t *p_msg;
    int32_t partition_id;
    struct tfm_conn_handle_t *p_conn_handle =
                                    tfm_spm_to_handle_instance(msg_handle);

    if (is_valid_chunk_data_in_pool(
        conn_handle_pool, (uint8_t *)p_conn_handle) != 1) {
        return NULL;
    }

    p_msg = &p_conn_handle->internal_msg;

    /*
     * Check that the magic number is correct. This proves that the message
     * structure contains an active message.
     */
    if (p_msg->magic != TFM_MSG_MAGIC) {
        return NULL;
    }

    /* Check that the running partition owns the message */
    partition_id = tfm_spm_partition_get_running_partition_id();
    if (partition_id != p_msg->service->partition->p_ldinf->pid) {
        return NULL;
    }

    return p_msg;
}

struct tfm_msg_body_t *
 tfm_spm_get_msg_buffer_from_conn_handle(struct tfm_conn_handle_t *conn_handle)
{
    TFM_CORE_ASSERT(conn_handle != NULL);

    return &(conn_handle->internal_msg);
}

void tfm_spm_fill_msg(struct tfm_msg_body_t *msg,
                      struct service_t *service,
                      psa_handle_t handle,
                      int32_t type, int32_t client_id,
                      psa_invec *invec, size_t in_len,
                      psa_outvec *outvec, size_t out_len,
                      psa_outvec *caller_outvec)
{
    uint32_t i;
    struct tfm_conn_handle_t *conn_handle;

    TFM_CORE_ASSERT(msg);
    TFM_CORE_ASSERT(service);
    TFM_CORE_ASSERT(!(invec == NULL && in_len != 0));
    TFM_CORE_ASSERT(!(outvec == NULL && out_len != 0));
    TFM_CORE_ASSERT(in_len <= PSA_MAX_IOVEC);
    TFM_CORE_ASSERT(out_len <= PSA_MAX_IOVEC);
    TFM_CORE_ASSERT(in_len + out_len <= PSA_MAX_IOVEC);

    /* Clear message buffer before using it */
    spm_memset(&msg->msg, 0, sizeof(psa_msg_t));

    THRD_SYNC_INIT(&msg->ack_evnt);
    msg->magic = TFM_MSG_MAGIC;
    msg->service = service;
    msg->p_client = GET_CURRENT_COMPONENT();
    msg->caller_outvec = caller_outvec;
    msg->msg.client_id = client_id;

    /* Copy contents */
    msg->msg.type = type;

    for (i = 0; i < in_len; i++) {
        msg->msg.in_size[i] = invec[i].len;
        msg->invec[i].base = invec[i].base;
    }

    for (i = 0; i < out_len; i++) {
        msg->msg.out_size[i] = outvec[i].len;
        msg->outvec[i].base = outvec[i].base;
        /* Out len is used to record the writed number, set 0 here again */
        msg->outvec[i].len = 0;
    }

    /* Use the user connect handle as the message handle */
    msg->msg.handle = handle;

    conn_handle = tfm_spm_to_handle_instance(handle);
    /* For connected handle, set rhandle to every message */
    if (conn_handle) {
        msg->msg.rhandle = tfm_spm_get_rhandle(service, conn_handle);
    }

    /* Set the private data of NSPE client caller in multi-core topology */
    if (TFM_CLIENT_ID_IS_NS(client_id)) {
        tfm_rpc_set_caller_data(msg, client_id);
    }
}

int32_t tfm_spm_partition_get_running_partition_id(void)
{
    struct partition_t *partition;

    partition = tfm_spm_get_running_partition();
    if (partition && partition->p_ldinf) {
        return partition->p_ldinf->pid;
    } else {
        return INVALID_PARTITION_ID;
    }
}

int32_t tfm_memory_check(const void *buffer, size_t len, bool ns_caller,
                         enum tfm_memory_access_e access,
                         uint32_t privileged)
{
    enum tfm_hal_status_t err;
    uint32_t attr = 0;

    /* If len is zero, this indicates an empty buffer and base is ignored */
    if (len == 0) {
        return SPM_SUCCESS;
    }

    if (!buffer) {
        return SPM_ERROR_BAD_PARAMETERS;
    }

    if ((uintptr_t)buffer > (UINTPTR_MAX - len)) {
        return SPM_ERROR_MEMORY_CHECK;
    }

    if (access == TFM_MEMORY_ACCESS_RW) {
        attr |= (TFM_HAL_ACCESS_READABLE | TFM_HAL_ACCESS_WRITABLE);
    } else {
        attr |= TFM_HAL_ACCESS_READABLE;
    }

    if (privileged == TFM_PARTITION_UNPRIVILEGED_MODE) {
        attr |= TFM_HAL_ACCESS_UNPRIVILEGED;
    } else {
        attr &= ~TFM_HAL_ACCESS_UNPRIVILEGED;
    }

    if (ns_caller) {
        attr |= TFM_HAL_ACCESS_NS;
    }

    err = tfm_hal_memory_has_access((uintptr_t)buffer, len, attr);

    if (err == TFM_HAL_SUCCESS) {
        return SPM_SUCCESS;
    }

    return SPM_ERROR_MEMORY_CHECK;
}

bool tfm_spm_is_ns_caller(void)
{
#if defined(TFM_MULTI_CORE_TOPOLOGY) || defined(FORWARD_PROT_MSG)
    /* Multi-core NS PSA API request is processed by pendSV. */
    return (__get_active_exc_num() == EXC_NUM_PENDSV);
#else
    struct partition_t *partition = tfm_spm_get_running_partition();

    if (!partition) {
        tfm_core_panic();
    }

    return (partition->p_ldinf->pid == TFM_SP_NON_SECURE_ID);
#endif
}

uint32_t tfm_spm_get_caller_privilege_mode(void)
{
    struct partition_t *partition;

#if defined(TFM_MULTI_CORE_TOPOLOGY) || defined(FORWARD_PROT_MSG)
    /*
     * In multi-core topology, if PSA request is from mailbox, the client
     * is unprivileged.
     */
    if (__get_active_exc_num() == EXC_NUM_PENDSV) {
        return TFM_PARTITION_UNPRIVILEGED_MODE;
    }
#endif
    partition = tfm_spm_get_running_partition();
    if (!partition) {
        tfm_core_panic();
    }

    return tfm_spm_partition_get_privileged_mode(partition->p_ldinf->flags);
}

int32_t tfm_spm_get_client_id(bool ns_caller)
{
    int32_t client_id;

    if (ns_caller) {
        client_id = tfm_nspm_get_current_client_id();
    } else {
        client_id = tfm_spm_partition_get_running_partition_id();
    }

    if (ns_caller != (client_id < 0)) {
        /* NS client ID must be negative and Secure ID must >= 0 */
        tfm_core_panic();
    }

    return client_id;
}

uint32_t tfm_spm_init(void)
{
    struct partition_t *partition;
    const struct partition_load_info_t *p_pldi;
    uint32_t service_setting = 0;

#ifdef TFM_FIH_PROFILE_ON
    fih_int fih_rc = FIH_FAILURE;
#endif

    tfm_pool_init(conn_handle_pool,
                  POOL_BUFFER_SIZE(conn_handle_pool),
                  sizeof(struct tfm_conn_handle_t),
                  TFM_CONN_HANDLE_MAX_NUM);

    UNI_LISI_INIT_HEAD(PARTITION_LIST_ADDR);
    UNI_LISI_INIT_HEAD(&services_listhead);

    /* Init the nonsecure context. */
#ifndef TFM_MULTI_CORE_TOPOLOGY
     tfm_nspm_ctx_init();
#endif

    while (1) {
        partition = load_a_partition_assuredly(PARTITION_LIST_ADDR);
        if (partition == NO_MORE_PARTITION) {
            break;
        }

        p_pldi = partition->p_ldinf;

        if (p_pldi->nservices) {
            service_setting = load_services_assuredly(
                                partition,
                                &services_listhead,
                                stateless_services_ref_tbl,
                                sizeof(stateless_services_ref_tbl));
        }

        if (p_pldi->nirqs) {
            load_irqs_assuredly(partition);
        }

        /* Bind the partition with platform. */
#if TFM_FIH_PROFILE_ON
        FIH_CALL(tfm_hal_bind_boundaries, fih_rc, partition->p_ldinf,
                 &partition->p_boundaries);
        if (fih_not_eq(fih_rc, fih_int_encode(TFM_HAL_SUCCESS))) {
            tfm_core_panic();
        }
#else /* TFM_FIH_PROFILE_ON */
        if (tfm_hal_bind_boundaries(partition->p_ldinf,
                                    &partition->p_boundaries)
                != TFM_HAL_SUCCESS) {
            tfm_core_panic();
        }
#endif /* TFM_FIH_PROFILE_ON */

        backend_instance.comp_init_assuredly(partition, service_setting);
    }

    return backend_instance.system_run();
}

/*
 * Return both current and next context to assembly via AAPCS trick:
 *   - Returning a 64 bit integer by 32-bit R0 and R1.
 *
 * This is architecture-specific, hence the scheduler entry and this
 * 'do_schedule' MAY be different on another architecture.
 */
union returning_contexts_t {
    struct {
        uint32_t curr;
        uint32_t next;
    } ctx;

    uint64_t curr_next_ctxs;
};

uint64_t do_schedule(void)
{
    union returning_contexts_t ret;
    struct partition_t *p_part_curr, *p_part_next;
    struct thread_t *pth_next = thrd_next();

    p_part_curr = GET_THRD_OWNER(CURRENT_THREAD);
    p_part_next = GET_THRD_OWNER(pth_next);

    if (pth_next != NULL && p_part_curr != p_part_next) {
        /* Check if there is enough room on stack to save more context */
        if ((p_part_curr->ctx_ctrl.sp_limit +
             sizeof(struct tfm_additional_context_t)) > __get_PSP()) {
            tfm_core_panic();
        }

        /*
         * If required, let the platform update boundary based on its
         * implementation. Change privilege, MPU or other configurations.
         */
        if (p_part_curr->p_boundaries != p_part_next->p_boundaries) {
            if (tfm_hal_update_boundaries(p_part_next->p_ldinf,
                                          p_part_next->p_boundaries)
                                                        != TFM_HAL_SUCCESS) {
                tfm_core_panic();
            }
        }
        ARCH_FLUSH_FP_CONTEXT();
    }

    /*
     * Handle pending mailbox message from NS in multi-core topology.
     * Empty operation on single Armv8-M platform.
     */
    tfm_rpc_client_call_handler();

    ret.ctx.curr = (uint32_t)CURRENT_THREAD->p_context_ctrl;
    ret.ctx.next = (uint32_t)pth_next->p_context_ctrl;

    CURRENT_THREAD = pth_next;

    return ret.curr_next_ctxs;
}

void update_caller_outvec_len(struct tfm_msg_body_t *msg)
{
    uint32_t i;

    /*
     * FixeMe: abstract these part into dedicated functions to avoid
     * accessing thread context in psa layer
     */
    /*
     * If it is a NS request via RPC, the owner of this message is not set.
     * Or if it is a SFN message, it does not have owner thread state either.
     */
    if ((!is_tfm_rpc_msg(msg)) && (msg->sfn_magic != TFM_MSG_MAGIC_SFN)) {
        TFM_CORE_ASSERT(msg->ack_evnt.owner->state == THRD_STATE_BLOCK);
    }

    for (i = 0; i < PSA_MAX_IOVEC; i++) {
        if (msg->msg.out_size[i] == 0) {
            continue;
        }

        TFM_CORE_ASSERT(msg->caller_outvec[i].base == msg->outvec[i].base);

        msg->caller_outvec[i].len = msg->outvec[i].len;
    }
}

void spm_assert_signal(void *p_pt, psa_signal_t signal)
{
    struct critical_section_t cs_assert = CRITICAL_SECTION_STATIC_INIT;
    struct partition_t *partition = (struct partition_t *)p_pt;

    if (!partition) {
        tfm_core_panic();
    }

    CRITICAL_SECTION_ENTER(cs_assert);

    partition->signals_asserted |= signal;

    if (partition->signals_waiting & signal) {
        thrd_wake_up(&partition->waitobj,
                     partition->signals_asserted & partition->signals_waiting);
        partition->signals_waiting &= ~signal;
    }

    CRITICAL_SECTION_LEAVE(cs_assert);
}

__attribute__((naked))
static psa_flih_result_t tfm_flih_deprivileged_handling(void *p_pt,
                                                        uintptr_t fn_flih,
                                                        void *p_context_ctrl)
{
    __ASM volatile("SVC %0           \n"
                   "BX LR            \n"
                   : : "I" (TFM_SVC_PREPARE_DEPRIV_FLIH));
}

void spm_handle_interrupt(void *p_pt, struct irq_load_info_t *p_ildi)
{
    psa_flih_result_t flih_result;
    struct partition_t *p_part;

    if (!p_pt || !p_ildi) {
        tfm_core_panic();
    }

    p_part = (struct partition_t *)p_pt;

    if (p_ildi->pid != p_part->p_ldinf->pid) {
        tfm_core_panic();
    }

    if (p_ildi->flih_func == NULL) {
        /* SLIH Model Handling */
        tfm_hal_irq_disable(p_ildi->source);
        flih_result = PSA_FLIH_SIGNAL;
    } else {
        /* FLIH Model Handling */
        if (tfm_spm_partition_get_privileged_mode(p_part->p_ldinf->flags) ==
                                                TFM_PARTITION_PRIVILEGED_MODE) {
            flih_result = p_ildi->flih_func();
        } else {
            flih_result = tfm_flih_deprivileged_handling(
                                                p_part,
                                                (uintptr_t)p_ildi->flih_func,
                                                CURRENT_THREAD->p_context_ctrl);
        }
    }

    if (flih_result == PSA_FLIH_SIGNAL) {
        spm_assert_signal(p_pt, p_ildi->signal);
    }
}

struct irq_load_info_t *get_irq_info_for_signal(
                                    const struct partition_load_info_t *p_ldinf,
                                    psa_signal_t signal)
{
    size_t i;
    struct irq_load_info_t *irq_info;

    if (!IS_ONLY_ONE_BIT_IN_UINT32(signal)) {
        return NULL;
    }

    irq_info = (struct irq_load_info_t *)LOAD_INFO_IRQ(p_ldinf);
    for (i = 0; i < p_ldinf->nirqs; i++) {
        if (irq_info[i].signal == signal) {
            return &irq_info[i];
        }
    }

    return NULL;
}