secure_fw/spm/spm_api.c

/*
 * Copyright (c) 2017, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *
 */

/* This file contains the apis exported by the SPM to tfm core */

#include <stdio.h>
#include "spm_db.h"
#include "spm_api.h"
#include "mpu_armv8m_drv.h"
#include "region_defs.h"
#include "secure_fw/core/tfm_core.h"

struct spm_service_db_t g_spm_service_db = {0,};

#define MPU_REGION_VENEERS   0
#define MPU_REGION_TFM_UNPRIV_CODE   1
#define MPU_REGION_TFM_UNPRIV_DATA   2
#define MPU_REGION_NS_DATA      3
#define SERVICE_REGION_RO       4
#define SERVICE_REGION_RW_STACK 5
#define SERVICE_REGION_PERIPH   6
#define SERVICE_REGION_SHARE    7

/* This should move to platform retarget */
struct mpu_armv8m_dev_t dev_mpu_s = { MPU_BASE };

typedef enum {
    TFM_INIT_FAILURE,
} ss_error_type_t;

/*
 * This function is called when a secure service causes an error.
 */
static void tfm_spm_service_err_handler(
    uint32_t ss_id, ss_error_type_t err_type, int32_t err_code)
{
    /*
     * FixMe: error handling to be added. E.g. service info to be updated with
     * init failed so that calls to the service are rejected
     */
#ifdef TFM_CORE_DEBUG
    if (err_type == TFM_INIT_FAILURE) {
        printf("Service init failed for service id 0x%08X\r\n", ss_id);
    } else {
        printf("Unknown service error %d for service id 0x%08X\r\n",
            err_type,
            ss_id);
    }
#endif
}

enum spm_err_t tfm_spm_db_init(void)
{
    /* This function initialises service db */
    g_spm_service_db.is_init = 1;

    g_spm_service_db.services_count =
        create_user_service_db(&g_spm_service_db, SPM_MAX_SERVICES);

    return SPM_ERR_OK;
}

#if TFM_LVL != 1
REGION_DECLARE(Image$$, TFM_UNPRIV_CODE, $$RO$$Base);
REGION_DECLARE(Image$$, TFM_UNPRIV_CODE, $$RO$$Limit);
REGION_DECLARE(Image$$, TFM_UNPRIV_RO_DATA, $$RW$$Base);
REGION_DECLARE(Image$$, TFM_UNPRIV_RO_DATA, $$ZI$$Limit);
REGION_DECLARE(Image$$, TFM_UNPRIV_SCRATCH, $$ZI$$Base);
REGION_DECLARE(Image$$, TFM_UNPRIV_SCRATCH, $$ZI$$Limit);

enum spm_err_t tfm_spm_mpu_init(void)
{
    mpu_armv8m_clean(&dev_mpu_s);

    struct mpu_armv8m_region_cfg_t region_cfg;

    /* Veneer region */
    region_cfg.region_nr = MPU_REGION_VENEERS;
    region_cfg.region_base = CMSE_VENEER_REGION_START;
    region_cfg.region_limit = CMSE_VENEER_REGION_LIMIT;
    region_cfg.attr_access = MPU_ARMV8M_AP_RO_PRIV_UNPRIV;
    region_cfg.attr_sh = MPU_ARMV8M_SH_NONE;
    region_cfg.attr_exec = MPU_ARMV8M_XN_EXEC_OK;
    mpu_armv8m_region_enable(&dev_mpu_s, &region_cfg);

    /* TFM Core unprivileged code region */
    region_cfg.region_nr = MPU_REGION_TFM_UNPRIV_CODE;
    region_cfg.region_base =
        (uint32_t)&REGION_NAME(Image$$, TFM_UNPRIV_CODE, $$RO$$Base);
    region_cfg.region_limit =
        (uint32_t)&REGION_NAME(Image$$, TFM_UNPRIV_CODE, $$RO$$Limit);
    region_cfg.attr_access = MPU_ARMV8M_AP_RO_PRIV_UNPRIV;
    region_cfg.attr_sh = MPU_ARMV8M_SH_NONE;
    region_cfg.attr_exec = MPU_ARMV8M_XN_EXEC_OK;
    mpu_armv8m_region_enable(&dev_mpu_s, &region_cfg);

    /* TFM Core unprivileged data region */
    region_cfg.region_nr = MPU_REGION_TFM_UNPRIV_DATA;
    region_cfg.region_base =
        (uint32_t)&REGION_NAME(Image$$, TFM_UNPRIV_RO_DATA, $$RW$$Base);
    region_cfg.region_limit =
        (uint32_t)&REGION_NAME(Image$$, TFM_UNPRIV_RO_DATA, $$ZI$$Limit);
    region_cfg.attr_access = MPU_ARMV8M_AP_RO_PRIV_UNPRIV;
    region_cfg.attr_sh = MPU_ARMV8M_SH_NONE;
    region_cfg.attr_exec = MPU_ARMV8M_XN_EXEC_NEVER;
    mpu_armv8m_region_enable(&dev_mpu_s, &region_cfg);

    /* TFM Core unprivileged non-secure data region */
    region_cfg.region_nr = MPU_REGION_NS_DATA;
    region_cfg.region_base = NS_DATA_START;
    region_cfg.region_limit = NS_DATA_LIMIT;
    region_cfg.attr_access = MPU_ARMV8M_AP_RW_PRIV_UNPRIV;
    region_cfg.attr_sh = MPU_ARMV8M_SH_NONE;
    region_cfg.attr_exec = MPU_ARMV8M_XN_EXEC_NEVER;
    mpu_armv8m_region_enable(&dev_mpu_s, &region_cfg);

    mpu_armv8m_enable(&dev_mpu_s, 1, 1);

    return SPM_ERR_OK;
}

enum spm_err_t tfm_spm_set_share_region(enum tfm_buffer_share_region_e share)
{
    enum spm_err_t res = SPM_ERR_INVALID_CONFIG;
    uint32_t scratch_base =
        (uint32_t)&REGION_NAME(Image$$, TFM_UNPRIV_SCRATCH, $$ZI$$Base);
    uint32_t scratch_limit =
        (uint32_t)&REGION_NAME(Image$$, TFM_UNPRIV_SCRATCH, $$ZI$$Limit);

    mpu_armv8m_disable(&dev_mpu_s);

    if (share == TFM_BUFFER_SHARE_DISABLE) {
        mpu_armv8m_region_disable(&dev_mpu_s, SERVICE_REGION_SHARE);
    } else {
        struct mpu_armv8m_region_cfg_t region_cfg;

        region_cfg.region_nr = SERVICE_REGION_SHARE;
        region_cfg.attr_access = MPU_ARMV8M_AP_RW_PRIV_UNPRIV;
        region_cfg.attr_sh = MPU_ARMV8M_SH_NONE;
        region_cfg.attr_exec = MPU_ARMV8M_XN_EXEC_NEVER;
        switch (share) {
        case TFM_BUFFER_SHARE_SCRATCH:
            /* Use scratch area for service-to-service data sharing */
            region_cfg.region_base = scratch_base;
            region_cfg.region_limit = scratch_limit;
            res = SPM_ERR_OK;
            break;
        case TFM_BUFFER_SHARE_NS_CODE:
            region_cfg.region_base = NS_CODE_START;
            region_cfg.region_limit = NS_CODE_LIMIT;
            /* Only allow read access to NS code region and keep
             * exec.never attribute
             */
            region_cfg.attr_access = MPU_ARMV8M_AP_RO_PRIV_UNPRIV;
            res = SPM_ERR_OK;
            break;
        default:
            res = SPM_ERR_INVALID_CONFIG;
            break;
        }
        if (res == SPM_ERR_OK) {
            mpu_armv8m_region_enable(&dev_mpu_s, &region_cfg);
        }
    }
    mpu_armv8m_enable(&dev_mpu_s, 1, 1);

    return res;
}
#endif

enum spm_err_t tfm_spm_service_init(void)
{
    struct spm_service_region_t *serv;
    int32_t fail_cnt = 0;
    uint32_t i;

    /* Call the init function for each service */
    /* FixMe: This implementation only fits level 1 isolation.
     * On higher levels MPU (and PPC) configuration need to be in place to have
     * proper isolation during init.
     */
    for (i = 0; i < g_spm_service_db.services_count; ++i) {
        serv = &g_spm_service_db.services[i];
        if (serv->periph_start) {
            ppc_configure_to_secure(serv->periph_ppc_bank,
                                    serv->periph_ppc_loc);
        }
        if (serv->service_init != 0) {
            int32_t ret = serv->service_init();

            if (ret != 0) {
                tfm_spm_service_err_handler(serv->service_id,
                    TFM_INIT_FAILURE, ret);
                fail_cnt++;
            }
        }
    }

    if (fail_cnt == 0) {
        return SPM_ERR_OK;
    } else {
        return SPM_ERR_SERV_NOT_AVAILABLE;
    }
}

#if TFM_LVL != 1
enum spm_err_t tfm_spm_service_sandbox_config(uint32_t service_id)
{
    /* This function takes a service id and enables the
     * SPM partition for that service
     */

    struct spm_service_region_t *serv;
    struct mpu_armv8m_region_cfg_t region_cfg;

    if (!g_spm_service_db.is_init) {
        return SPM_ERR_SERV_DB_NOT_INIT;
    }

    /*brute force id*/
    serv = &g_spm_service_db.services[SERVICE_ID_GET(service_id)];

    mpu_armv8m_disable(&dev_mpu_s);

    /* Configure Regions */

    /* RO region*/
    region_cfg.region_nr = SERVICE_REGION_RO;
    region_cfg.region_base = serv->ro_start;
    region_cfg.region_limit = serv->ro_limit;
    region_cfg.attr_access = MPU_ARMV8M_AP_RO_PRIV_UNPRIV;
    region_cfg.attr_sh = MPU_ARMV8M_SH_NONE;
    region_cfg.attr_exec = MPU_ARMV8M_XN_EXEC_OK;

    mpu_armv8m_region_enable(&dev_mpu_s, &region_cfg);

    /* RW, ZI and stack as one region*/
    region_cfg.region_nr = SERVICE_REGION_RW_STACK;
    region_cfg.region_base = serv->rw_start;
    region_cfg.region_limit = serv->stack_top;
    region_cfg.attr_access = MPU_ARMV8M_AP_RW_PRIV_UNPRIV;
    region_cfg.attr_sh = MPU_ARMV8M_SH_NONE;
    region_cfg.attr_exec = MPU_ARMV8M_XN_EXEC_NEVER;

    mpu_armv8m_region_enable(&dev_mpu_s, &region_cfg);

    if (serv->periph_start) {
        /* Peripheral */
        region_cfg.region_nr = SERVICE_REGION_PERIPH;
        region_cfg.region_base = serv->periph_start;
        region_cfg.region_limit = serv->periph_limit;
        region_cfg.attr_access = MPU_ARMV8M_AP_RW_PRIV_UNPRIV;
        region_cfg.attr_sh = MPU_ARMV8M_SH_NONE;
        region_cfg.attr_exec = MPU_ARMV8M_XN_EXEC_NEVER;
        mpu_armv8m_region_enable(&dev_mpu_s, &region_cfg);

        ppc_en_secure_unpriv(serv->periph_ppc_bank, serv->periph_ppc_loc);
    }

    mpu_armv8m_enable(&dev_mpu_s, 1, 1);

#ifndef UNPRIV_JUMP_TO_NS
    /* FixMe: if jump_to_ns_code() from unprivileged is solved,
     * this code can be removed
     */
    /* Initialization is done, set thread mode to unprivileged.
     */
    CONTROL_Type ctrl;

    ctrl.w = __get_CONTROL();
    ctrl.b.nPRIV = 1;
    __set_CONTROL(ctrl.w);
    __DSB();
    __ISB();
#endif

    return SPM_ERR_OK;
}

enum spm_err_t tfm_spm_service_sandbox_deconfig(uint32_t service_id)
{
    /* This function takes a service id and disables the
     * SPM partition for that service
     */

#ifndef UNPRIV_JUMP_TO_NS
    /* FixMe: if jump_to_ns_code() from unprivileged is solved,
     * this code can be removed
     */
    CONTROL_Type ctrl;

    ctrl.w = __get_CONTROL();
    ctrl.b.nPRIV = 0;
    __set_CONTROL(ctrl.w);
    __DSB();
    __ISB();
#endif

    struct spm_service_region_t *serv;

    serv = &g_spm_service_db.services[SERVICE_ID_GET(service_id)];

    if (serv->periph_start) {
        /* Peripheral */
        ppc_clr_secure_unpriv(serv->periph_ppc_bank, serv->periph_ppc_loc);
    }

    mpu_armv8m_disable(&dev_mpu_s);
    mpu_armv8m_region_disable(&dev_mpu_s, SERVICE_REGION_RO);
    mpu_armv8m_region_disable(&dev_mpu_s, SERVICE_REGION_RW_STACK);
    mpu_armv8m_region_disable(&dev_mpu_s, SERVICE_REGION_PERIPH);
    mpu_armv8m_region_disable(&dev_mpu_s, SERVICE_REGION_SHARE);
    mpu_armv8m_enable(&dev_mpu_s, 1, 1);

    return SPM_ERR_OK;
}

uint32_t tfm_spm_service_get_stack(uint32_t service_id)
{
    return g_spm_service_db.services[SERVICE_ID_GET(service_id)].stack_ptr;
}

uint32_t tfm_spm_service_get_stack_bottom(uint32_t service_id)
{
    return g_spm_service_db.services[SERVICE_ID_GET(service_id)].stack_bottom;
}

uint32_t tfm_spm_service_get_stack_top(uint32_t service_id)
{
    return g_spm_service_db.services[SERVICE_ID_GET(service_id)].stack_top;
}

void tfm_spm_service_set_stack(uint32_t service_id, uint32_t stack_ptr)
{
    g_spm_service_db.services[SERVICE_ID_GET(service_id)].stack_ptr = stack_ptr;
}
#endif