esp-idf/components/esp_system/task_wdt/task_wdt.c

/*
 * SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <sys/queue.h>
#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/task_snapshot.h"
#include "esp_err.h"
#include "esp_attr.h"
#include "esp_check.h"
#include "esp_log.h"
#include "esp_debug_helpers.h"
#include "esp_freertos_hooks.h"
#include "esp_task_wdt.h"
#include "esp_private/system_internal.h"
#include "esp_private/crosscore_int.h"
#include "esp_private/esp_task_wdt.h"
#include "esp_private/esp_task_wdt_impl.h"

#if CONFIG_ESP_SYSTEM_USE_EH_FRAME
#include "esp_private/eh_frame_parser.h"
#endif // CONFIG_ESP_SYSTEM_USE_EH_FRAME


#if CONFIG_IDF_TARGET_ARCH_RISCV && !CONFIG_ESP_SYSTEM_USE_EH_FRAME
/* Function used to print all the registers pointed by the given frame .*/
extern void panic_print_registers(const void *frame, int core);
#endif // CONFIG_IDF_TARGET_ARCH_RISCV && !CONFIG_ESP_SYSTEM_USE_EH_FRAME

/* We will use this function in order to simulate an `abort()` occurring in
 * a different context than the one it's called from. */
extern void xt_unhandled_exception(void *frame);

/* Forward declaration of the idle hook callback */
static bool idle_hook_cb(void);

/* Global flag set to make the `panic` mechanism think a real `abort()` was
 * called. This is used in the ISR handler, in case we have to panic when
 * a task doesn't feed its timer. */
extern bool g_panic_abort;

/* Global flag marking whether the current ISR is a Task Watchdog ISR. */
bool g_twdt_isr = false;

// --------------------------------------------------- Definitions -----------------------------------------------------

// ---------------------- Typedefs -------------------------

/**
 * @brief Structure used for each subscribed task
 */
typedef struct twdt_entry twdt_entry_t;
struct twdt_entry {
    SLIST_ENTRY(twdt_entry) slist_entry;
    TaskHandle_t task_handle;   // NULL if user entry
    const char *user_name;      // NULL if task entry
    bool has_reset;
};

// Structure used to hold run time configuration of the TWDT
typedef struct twdt_obj twdt_obj_t;
struct twdt_obj {
    twdt_ctx_t impl_ctx;
    SLIST_HEAD(entry_list_head, twdt_entry) entries_slist;
    uint32_t idle_core_mask;    // Current core's who's idle tasks are subscribed
    bool panic; // Flag to trigger panic when TWDT times out
    bool waiting_for_task; // Flag to start the timer as soon as a task is added
};

// ----------------------- Objects -------------------------

static const char *TAG = "task_wdt";
static portMUX_TYPE spinlock = portMUX_INITIALIZER_UNLOCKED;
static twdt_obj_t *p_twdt_obj = NULL;

#if CONFIG_FREERTOS_SMP
#define CORE_USER_NAME_LEN      8   // Long enough for "CPU XXX"
static esp_task_wdt_user_handle_t core_user_handles[portNUM_PROCESSORS] = {NULL};
static char core_user_names[portNUM_PROCESSORS][CORE_USER_NAME_LEN];
#endif

// ----------------------------------------------------- Private -------------------------------------------------------

// ----------------------- Helpers -------------------------

/**
 * @brief Reset the timer and reset flags of each entry
 * When entering this function, the spinlock has already been taken, no need to take it back.
 */
static void task_wdt_timer_feed(void)
{
    esp_task_wdt_impl_timer_feed(p_twdt_obj->impl_ctx);

    /* Clear the has_reset flag in each entry */
    twdt_entry_t *entry;
    SLIST_FOREACH(entry, &p_twdt_obj->entries_slist, slist_entry) {
        entry->has_reset = false;
    }
}

/**
 * @brief Checks whether a user entry exists and if all other entries have been reset
 *
 * @param[in] user_entry User entry
 * @param[out] all_reset Whether all entries have been reset
 * @return Whether the user entry exists
 */
static bool find_entry_and_check_all_reset(twdt_entry_t *user_entry, bool *all_reset)
{
    bool found_user_entry = false;
    bool found_non_reset = false;

    twdt_entry_t *entry;
    SLIST_FOREACH(entry, &p_twdt_obj->entries_slist, slist_entry) {
        if (entry == user_entry) {
            found_user_entry = true;
        } else if (entry->has_reset == false) {
            found_non_reset = true;
        }
    }

    *all_reset = !found_non_reset;
    return found_user_entry;
}

/**
 * @brief Find whether a task entry exists, and checks if all other entries have been reset
 *
 * @param[in] handle Task handle
 * @param[out] all_reset Whether all entries have been reset
 * @return Task entry, or NULL if not found
 */
static twdt_entry_t *find_entry_from_task_handle_and_check_all_reset(TaskHandle_t handle, bool *all_reset)
{
    twdt_entry_t *target = NULL;
    bool found_non_reset = false;

    twdt_entry_t *entry;
    SLIST_FOREACH(entry, &p_twdt_obj->entries_slist, slist_entry) {
        if (entry->task_handle == handle) {
            target = entry;
        } else if (entry->has_reset == false) {
            found_non_reset = true;
        }
    }

    *all_reset = !found_non_reset;
    return target;
}

/**
 * @brief Create a task/user entry and add it to the task WDT
 *
 * @param[in] is_task Whether the entry is a task entry or user entry
 * @param[in] entry_data Data associated with the entry (either a task handle or user entry name)
 * @param[out] entry_ret Pointer to created entry
 * @return ESP_OK if entry was added, failure otherwise
 */
static esp_err_t add_entry(bool is_task, void *entry_data, twdt_entry_t **entry_ret)
{
    esp_err_t ret;

    // Allocate entry object
    twdt_entry_t *entry = calloc(1, sizeof(twdt_entry_t));
    if (entry == NULL) {
        return ESP_ERR_NO_MEM;
    }
    if (is_task) {
        entry->task_handle = (TaskHandle_t)entry_data;
    } else {
        entry->user_name = (const char *)entry_data;
    }

    portENTER_CRITICAL(&spinlock);
    // Check TWDT state
    ESP_GOTO_ON_FALSE_ISR((p_twdt_obj != NULL), ESP_ERR_INVALID_STATE, state_err, TAG, "task watchdog was never initialized");
    // Check if the task is an entry, and if all entries have been reset
    bool all_reset;
    if (is_task) {
        twdt_entry_t *entry_found = find_entry_from_task_handle_and_check_all_reset(entry->task_handle, &all_reset);
        ESP_GOTO_ON_FALSE_ISR((entry_found == NULL), ESP_ERR_INVALID_ARG, state_err, TAG, "task is already subscribed");
    } else {
        bool entry_found = find_entry_and_check_all_reset(entry, &all_reset);
        ESP_GOTO_ON_FALSE_ISR(!entry_found, ESP_ERR_INVALID_ARG, state_err, TAG, "user is already subscribed");
    }
    // Add entry to list
    SLIST_INSERT_HEAD(&p_twdt_obj->entries_slist, entry, slist_entry);
    // Start the timer if it has not been started yet and was waiting on a task to registered
    if (p_twdt_obj->waiting_for_task) {
        esp_task_wdt_impl_timer_restart(p_twdt_obj->impl_ctx);
        p_twdt_obj->waiting_for_task = false;
    }
    if (all_reset) {   //Reset hardware timer if all other tasks in list have reset in
        task_wdt_timer_feed();
    }
    portEXIT_CRITICAL(&spinlock);
    *entry_ret = entry;
    return ESP_OK;

state_err:
    portEXIT_CRITICAL(&spinlock);
    free(entry);
    return ret;
}

/**
 * @brief Delete a task/user entry
 *
 * @param[in] is_task Whether the entry is a task entry or user entry
 * @param[in] entry_data Data associated with the entry (either a task handle or user entry name)
 * @return ESP_OK if entry was deleted, failure otherwise
 */
static esp_err_t delete_entry(bool is_task, void *entry_data)
{
    esp_err_t ret;

    portENTER_CRITICAL(&spinlock);
    // Check TWDT state
    ESP_GOTO_ON_FALSE_ISR((p_twdt_obj != NULL), ESP_ERR_INVALID_STATE, err, TAG, "task watchdog was never initialized");
    // Find entry for task
    bool all_reset;
    twdt_entry_t *entry;
    if (is_task) {
        entry = find_entry_from_task_handle_and_check_all_reset((TaskHandle_t)entry_data, &all_reset);
        ESP_GOTO_ON_FALSE_ISR((entry != NULL), ESP_ERR_NOT_FOUND, err, TAG, "task not found");
    } else {
        entry = (twdt_entry_t *)entry_data;
        bool entry_found = find_entry_and_check_all_reset(entry, &all_reset);
        ESP_GOTO_ON_FALSE_ISR(entry_found, ESP_ERR_NOT_FOUND, err, TAG, "user not found");
    }
    // Remove entry
    SLIST_REMOVE(&p_twdt_obj->entries_slist, entry, twdt_entry, slist_entry);
    /* Stop the timer if we don't have any more tasks/objects to watch */
    if (SLIST_EMPTY(&p_twdt_obj->entries_slist)) {
        p_twdt_obj->waiting_for_task = true;
        esp_task_wdt_impl_timer_stop(p_twdt_obj->impl_ctx);
    } else {
        p_twdt_obj->waiting_for_task = false;
    }
    /* Reset hardware timer if all remaining tasks have reset and if the list of tasks is not empty */
    if (!p_twdt_obj->waiting_for_task && all_reset) {
        task_wdt_timer_feed();
    }
    portEXIT_CRITICAL(&spinlock);
    free(entry);
    return ESP_OK;

err:
    portEXIT_CRITICAL(&spinlock);
    return ret;
}

/**
 * @brief Unsubscribe the idle tasks of one or more cores
 *
 * @param core_mask
 */
static void unsubscribe_idle(uint32_t core_mask)
{
    int core_num = 0;
    while (core_mask != 0) {
        if (core_mask & 0x1) {
#if CONFIG_FREERTOS_SMP
            assert(core_user_handles[core_num]);
            esp_deregister_freertos_idle_hook_for_cpu(idle_hook_cb, core_num);
            ESP_ERROR_CHECK(esp_task_wdt_delete_user(core_user_handles[core_num]));
            core_user_handles[core_num] = NULL;
#else // CONFIG_FREERTOS_SMP
            TaskHandle_t idle_task_handle = xTaskGetIdleTaskHandleForCPU(core_num);
            assert(idle_task_handle);
            esp_deregister_freertos_idle_hook_for_cpu(idle_hook_cb, core_num);
            ESP_ERROR_CHECK(esp_task_wdt_delete(idle_task_handle));
#endif // CONFIG_FREERTOS_SMP
        }
        core_mask >>= 1;
        core_num++;
    }
}


/**
 * @brief Subscribes the idle tasks of one or more cores
 *
 * @param core_mask Bit mask of cores to subscribe
 */
static void subscribe_idle(uint32_t core_mask)
{
    int core_num = 0;
    while (core_mask != 0) {
        if (core_mask & 0x1) {
#if CONFIG_FREERTOS_SMP
            snprintf(core_user_names[core_num], CORE_USER_NAME_LEN, "CPU %d", (uint8_t)core_num);
            ESP_ERROR_CHECK(esp_task_wdt_add_user((const char *)core_user_names[core_num], &core_user_handles[core_num]));
            ESP_ERROR_CHECK(esp_register_freertos_idle_hook_for_cpu(idle_hook_cb, core_num));
#else // CONFIG_FREERTOS_SMP
            TaskHandle_t idle_task_handle = xTaskGetIdleTaskHandleForCPU(core_num);
            assert(idle_task_handle);
            ESP_ERROR_CHECK(esp_task_wdt_add(idle_task_handle));
            ESP_ERROR_CHECK(esp_register_freertos_idle_hook_for_cpu(idle_hook_cb, core_num));
#endif // CONFIG_FREERTOS_SMP
        }
        core_mask >>= 1;
        core_num++;
    }
}


/**
 * The behavior of the Task Watchdog depends on the configuration from the `menuconfig`.
 * It can be summarized as follow, regardless of the target:
 * +------------------------+--------------------------------+--------------------------+
 * | \  Panic configuration |                                |                          |
 * |  +------------------+  | Panic Enabled                  | Panic Disabled           |
 * | TWDT triggered on    \ |                                |                          |
 * +------------------------+--------------------------------+--------------------------+
 * |                        | - Current core backtrace       | - Current core backtrace |
 * | Both Cores             | - Crosscore TWDT abort         | - Crosscore backtrace    |
 * |                        | - Wait for other core to abort |                          |
 * +------------------------+--------------------------------+--------------------------+
 * | Other Core             | - Crosscore TWDT abort         | - Crosscore backtrace    |
 * +------------------------+--------------------------------+--------------------------+
 * | Current Core           | - Abort from current CPU       | - Current core backtrace |
 * +------------------------+--------------------------------+--------------------------+
 *
 */

#if CONFIG_IDF_TARGET_ARCH_RISCV

static void task_wdt_timeout_handling(int cores_fail, bool panic)
{
    /* For RISC-V, make sure the cores that fail is only composed of core 0. */
    assert(cores_fail == BIT(0));

    const int current_core = 0;
    TaskSnapshot_t snapshot = { 0 };
    BaseType_t ret = vTaskGetSnapshot(xTaskGetCurrentTaskHandle(), &snapshot);

    if (p_twdt_obj->panic) {
        assert(ret == pdTRUE);
        ESP_EARLY_LOGE(TAG, "Aborting.");
        esp_reset_reason_set_hint(ESP_RST_TASK_WDT);
        /**
         * We cannot simply use `abort` here because the `panic` handler would
         * interpret it as if the task watchdog ISR aborted and so, print this
         * current ISR backtrace/context. We want to trick the `panic` handler
         * to think the task itself is aborting.
         * To do so, we need to get the interruptee's top of the stack. It contains
         * its own context, saved when the interrupt occurred.
         * We must also set the global flag that states that an abort occurred
         * (and not a panic)
         **/
        g_panic_abort = true;
        g_twdt_isr = true;
        void *frame = (void *) snapshot.pxTopOfStack;
#if CONFIG_ESP_SYSTEM_USE_EH_FRAME
        ESP_EARLY_LOGE(TAG, "Print CPU %d (current core) backtrace", current_core);
#endif // CONFIG_ESP_SYSTEM_USE_EH_FRAME
        xt_unhandled_exception(frame);
    } else {
        /* Targets based on a RISC-V CPU cannot perform backtracing that easily.
         * We have two options here:
         *     - Perform backtracing at runtime.
         *     - Let IDF monitor do the backtracing for us. Used during panic already.
         * This could be configurable, choosing one or the other depending on
         * CONFIG_ESP_SYSTEM_USE_EH_FRAME configuration option.
         *
         * In both cases, this takes time, and we are in an ISR, we must
         * exit this handler as fast as possible, then we will simply print
         * the interruptee's registers.
         */
        if (ret == pdTRUE) {
            void *frame = (void *) snapshot.pxTopOfStack;
#if CONFIG_ESP_SYSTEM_USE_EH_FRAME
            ESP_EARLY_LOGE(TAG, "Print CPU %d (current core) backtrace", current_core);
            esp_eh_frame_print_backtrace(frame);
#else // CONFIG_ESP_SYSTEM_USE_EH_FRAME
            ESP_EARLY_LOGE(TAG, "Print CPU %d (current core) registers", current_core);
            panic_print_registers(frame, current_core);
            esp_rom_printf("\r\n");
#endif // CONFIG_ESP_SYSTEM_USE_EH_FRAME
        }
    }
}

#else // CONFIG_IDF_TARGET_ARCH_RISCV

/**
 * Function simulating an abort coming from the interrupted task of the current
 * core.
 * It is called either by the function right below or by a crosscore interrupt,
 * in the case where the other core (than the main one) has to abort because one
 * of his tasks didn't reset the TWDT on time.
 */
void task_wdt_timeout_abort_xtensa(bool current_core)
{
    TaskSnapshot_t snapshot = { 0 };
    BaseType_t ret = pdTRUE;

    ESP_EARLY_LOGE(TAG, "Aborting.");
    esp_reset_reason_set_hint(ESP_RST_TASK_WDT);
    ret = vTaskGetSnapshot(xTaskGetCurrentTaskHandle(), &snapshot);
    assert(ret == pdTRUE);
    g_panic_abort = true;
    /* For Xtensa, we should set this flag as late as possible, as this function may
     * be called after a crosscore interrupt. Indeed, a higher interrupt may occur
     * after calling the crosscore interrupt, if its handler fails, this flag
     * shall not be set.
     * This flag will tell the coredump component (if activated) that yes, we are in
     * an ISR context, but it is intended, it is not because an ISR encountered an
     * exception. If we don't set such flag, later tested by coredump, the later would
     * switch the execution frame/context we are giving it to the interrupt stack.
     * For details about this behavior in the TODO task: IDF-5694
     */
    g_twdt_isr = true;
    void *frame = (void *) snapshot.pxTopOfStack;
    if (current_core) {
        ESP_EARLY_LOGE(TAG, "Print CPU %d (current core) backtrace", xPortGetCoreID());
    } else {
        ESP_EARLY_LOGE(TAG, "Print CPU %d backtrace", xPortGetCoreID());
    }
    xt_unhandled_exception(frame);
}

static void task_wdt_timeout_handling(int cores_fail, bool panic)
{
    const int current_core = xPortGetCoreID();

    if (panic) {
#if !CONFIG_FREERTOS_UNICORE
        const int other_core = !current_core;

        if ((cores_fail & BIT(0)) && (cores_fail & BIT(1))) {
            /* In the case where both CPUs have failing tasks, print the current CPU backtrace and then let the
             * other core fail. */
            ESP_EARLY_LOGE(TAG, "Print CPU %d (current core) backtrace", current_core);
            esp_backtrace_print(100);
            /* TODO: the interrupt we send should have the highest priority */
            esp_crosscore_int_send_twdt_abort(other_core);
            /* We are going to abort, on the other core, we have nothing to
             * do anymore here, just wait until we crash */
            while (1) {}
        } else if (cores_fail & BIT(other_core)) {
            /* If only the other core is failing, we can tell it to abort. */
            esp_crosscore_int_send_twdt_abort(other_core);
            while (1) {}
        }
#endif // !CONFIG_FREERTOS_UNICORE
        /* Current core is failing, abort right now */
        task_wdt_timeout_abort_xtensa(true);
    } else {
        /* Print backtrace of the core that failed to reset the watchdog */
        if (cores_fail & BIT(current_core)) {
            ESP_EARLY_LOGE(TAG, "Print CPU %d (current core) backtrace", current_core);
            esp_backtrace_print(100);
        }
#if !CONFIG_FREERTOS_UNICORE
        const int other_core = !current_core;
        if (cores_fail & BIT(other_core)) {
            ESP_EARLY_LOGE(TAG, "Print CPU %d backtrace", other_core);
            esp_crosscore_int_send_print_backtrace(other_core);
        }
#endif // !CONFIG_FREERTOS_UNICORE
    }
}

#endif // CONFIG_IDF_TARGET_ARCH_RISCV


// ---------------------- Callbacks ------------------------

/**
 * @brief Idle hook callback
 *
 * Idle hook callback called by the idle tasks to feed the TWDT
 *
 * @return Whether the idle tasks should continue idling
 */
static bool idle_hook_cb(void)
{
#if CONFIG_FREERTOS_SMP
    esp_task_wdt_reset_user(core_user_handles[xPortGetCoreID()]);
#else // CONFIG_FREERTOS_SMP
    esp_task_wdt_reset();
#endif // CONFIG_FREERTOS_SMP
    return true;
}

/**
 * @brief TWDT timeout ISR function
 *
 * The ISR checks which entries have not been reset, prints some debugging information, and triggers a panic if
 * configured to do so.
 *
 * @param arg ISR argument
 */
static void task_wdt_isr(void *arg)
{
    portENTER_CRITICAL_ISR(&spinlock);
    esp_task_wdt_impl_timeout_triggered(p_twdt_obj->impl_ctx);

    // If there are no entries, there's nothing to do.
    if (SLIST_EMPTY(&p_twdt_obj->entries_slist)) {
        portEXIT_CRITICAL_ISR(&spinlock);
        return;
    }
    // Find what entries triggered the TWDT timeout (i.e., which entries have not been reset)
    /*
    Note: We are currently in a critical section, thus under normal circumstances, logging should not be allowed.
    However, TWDT timeouts count as fatal errors, thus reporting the fatal error is considered more important than
    minimizing interrupt latency. Thus we allow logging in critical sections in this narrow case.
    */
    ESP_EARLY_LOGE(TAG, "Task watchdog got triggered. The following tasks/users did not reset the watchdog in time:");
    twdt_entry_t *entry;
    /* Keep a bitmap of CPU cores having tasks that have not reset TWDT.
     * Bit 0 represents core 0, bit 1 represents core 1, and so on. */
    int cpus_fail = 0;
    bool panic = p_twdt_obj->panic;

    SLIST_FOREACH(entry, &p_twdt_obj->entries_slist, slist_entry) {
        if (!entry->has_reset) {
            if (entry->task_handle) {
#if CONFIG_FREERTOS_SMP
#if configNUM_CORES > 1
                // Log the task's name and its affinity
                const UBaseType_t affinity = vTaskCoreAffinityGet(entry->task_handle);
                ESP_EARLY_LOGE(TAG, " - %s (0x%x)", pcTaskGetName(entry->task_handle), affinity);
                cpus_fail |= affinity;
#else // configNUM_CORES > 1
                // Log the task's name
                ESP_EARLY_LOGE(TAG, " - %s", pcTaskGetName(entry->task_handle));
                cpus_fail |= BIT(0);
#endif // configNUM_CORES > 1
#else // CONFIG_FREERTOS_SMP
                BaseType_t task_affinity = xTaskGetAffinity(entry->task_handle);
                const char *cpu;
                if (task_affinity == 0) {
                    cpu = DRAM_STR("CPU 0");
                    cpus_fail |= BIT(0);
                } else if (task_affinity == 1) {
                    cpu = DRAM_STR("CPU 1");
                    cpus_fail |= BIT(1);
                } else {
                    cpu = DRAM_STR("CPU 0/1");
                    cpus_fail |= BIT(1) | BIT(0);
                }
                ESP_EARLY_LOGE(TAG, " - %s (%s)", pcTaskGetName(entry->task_handle), cpu);
#endif // CONFIG_FREERTOS_SMP
            } else {
                /* User entry, we cannot predict on which core it is scheduled to run,
                 * so let's mark all cores as failing */
#if configNUM_CORES > 1
                cpus_fail = BIT(1) | BIT(0);
#else // configNUM_CORES > 1
                cpus_fail = BIT(0);
#endif // configNUM_CORES > 1
                ESP_EARLY_LOGE(TAG, " - %s", entry->user_name);
            }
        }
    }
    ESP_EARLY_LOGE(TAG, "%s", DRAM_STR("Tasks currently running:"));
    for (int x = 0; x < portNUM_PROCESSORS; x++) {
        ESP_EARLY_LOGE(TAG, "CPU %d: %s", x, pcTaskGetName(xTaskGetCurrentTaskHandleForCPU(x)));
    }
    portEXIT_CRITICAL_ISR(&spinlock);

    /* Run user ISR handler.
     * This function has been declared as weak, thus, it may be possible that it was not defines.
     * to check this, we can directly test its address. In any case, the linker will get rid of
     * this `if` when linking, this means that if the function was not defined, the whole `if`
     * block will be discarded (zero runtime overhead), else only the function call will be kept.
     */
    if (esp_task_wdt_isr_user_handler != NULL) {
        esp_task_wdt_isr_user_handler();
    }

    // Trigger configured timeout behavior (e.g., panic or print backtrace)
    assert(cpus_fail != 0);
    task_wdt_timeout_handling(cpus_fail, panic);
}

// ----------------------------------------------------- Public --------------------------------------------------------

esp_err_t esp_task_wdt_init(const esp_task_wdt_config_t *config)
{
    ESP_RETURN_ON_FALSE((config != NULL && config->idle_core_mask < (1 << portNUM_PROCESSORS)), ESP_ERR_INVALID_ARG, TAG, "Invalid arguments");
    ESP_RETURN_ON_FALSE(p_twdt_obj == NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT already initialized");
    esp_err_t ret = ESP_OK;
    twdt_obj_t *obj = NULL;

    /* Allocate and initialize the global object */
    obj = calloc(1, sizeof(twdt_obj_t));
    ESP_GOTO_ON_FALSE((obj != NULL), ESP_ERR_NO_MEM, err, TAG, "insufficient memory");
    SLIST_INIT(&obj->entries_slist);
    obj->panic = config->trigger_panic;

    /* Allocate the timer itself, NOT STARTED */
    ret = esp_task_wdt_impl_timer_allocate(config, task_wdt_isr, &obj->impl_ctx);
    if (ret != ESP_OK) {
        goto err;
    }

    /* No error so far, we can assign it to the driver object */
    p_twdt_obj = obj;

    /* Update which core's idle tasks are subscribed */
    p_twdt_obj->idle_core_mask = config->idle_core_mask;
    if (config->idle_core_mask) {
        /* Subscribe the new cores idle tasks */
        subscribe_idle(config->idle_core_mask);
    }

    /* Start the timer only if we are watching some tasks */
    if (!SLIST_EMPTY(&p_twdt_obj->entries_slist)) {
        p_twdt_obj->waiting_for_task = false;
        esp_task_wdt_impl_timer_restart(p_twdt_obj->impl_ctx);
    } else {
        p_twdt_obj->waiting_for_task = true;
    }

    return ESP_OK;
err:
    free(obj);
    return ret;
}

esp_err_t esp_task_wdt_reconfigure(const esp_task_wdt_config_t *config)
{
    ESP_RETURN_ON_FALSE((config != NULL && config->idle_core_mask < (1 << portNUM_PROCESSORS)), ESP_ERR_INVALID_ARG, TAG, "Invalid arguments");
    ESP_RETURN_ON_FALSE(p_twdt_obj != NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT not initialized yet");
    uint32_t old_core_mask = 0;
    esp_err_t ret = ESP_OK;

    /* Stop the timer to make sure we don't get into the ISR while reconfiguring the TWDT */
    portENTER_CRITICAL(&spinlock);
    ret = esp_task_wdt_impl_timer_stop(p_twdt_obj->impl_ctx);
    if (ret != ESP_OK) {
        goto err;
    }

    /* We can start reconfiguring the tasks */
    p_twdt_obj->panic = config->trigger_panic;

    /* Reconfigure the timer underneath (without restarting it) */
    ret = esp_task_wdt_impl_timer_reconfigure(p_twdt_obj->impl_ctx, config);
    if (ret != ESP_OK) {
        goto err;
    }

    old_core_mask = p_twdt_obj->idle_core_mask;
    /* If the new mask is different than the old one, we have to subscribe the new idle tasks */
    if (old_core_mask != config->idle_core_mask) {
        p_twdt_obj->idle_core_mask = config->idle_core_mask;

        /* Unsubscribe all previously watched core idle tasks */
        unsubscribe_idle(old_core_mask);

        if (config->idle_core_mask) {
            /* Subscribe the new cores idle tasks */
            subscribe_idle(config->idle_core_mask);
        }
    }

    /* Start the timer only if we are watching some tasks */
    if (!SLIST_EMPTY(&p_twdt_obj->entries_slist)) {
        esp_task_wdt_impl_timer_restart(p_twdt_obj->impl_ctx);
    }

    portEXIT_CRITICAL(&spinlock);
err:
    return ESP_OK;
}

esp_err_t esp_task_wdt_stop(void)
{
    esp_err_t ret = ESP_OK;

    /* If the timer has not been initialized, do not attempt to stop it */
    if (p_twdt_obj == NULL) {
        ret = ESP_ERR_INVALID_STATE;
    }

    if (ret == ESP_OK) {
        portENTER_CRITICAL(&spinlock);
        ret = esp_task_wdt_impl_timer_stop(p_twdt_obj->impl_ctx);
        portEXIT_CRITICAL(&spinlock);
    }

    return ret;
}

esp_err_t esp_task_wdt_restart(void)
{
    esp_err_t ret = ESP_OK;

    /* If the timer has not been initialized, do not attempt to stop it */
    if (p_twdt_obj == NULL) {
        ret = ESP_ERR_INVALID_STATE;
    }

    if (ret == ESP_OK) {
        portENTER_CRITICAL(&spinlock);
        ret = esp_task_wdt_impl_timer_restart(p_twdt_obj->impl_ctx);
        portEXIT_CRITICAL(&spinlock);
    }

    return ret;
}

esp_err_t esp_task_wdt_deinit(void)
{
    esp_err_t ret;

    ESP_RETURN_ON_FALSE(p_twdt_obj != NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT was never initialized");

    // Unsubscribe all previously watched core idle tasks
    unsubscribe_idle(p_twdt_obj->idle_core_mask);

    // Check TWDT state
    ESP_GOTO_ON_FALSE_ISR(SLIST_EMPTY(&p_twdt_obj->entries_slist), ESP_ERR_INVALID_STATE, err, TAG, "Tasks/users still subscribed");

    // Disable the timer
    esp_task_wdt_impl_timer_stop(p_twdt_obj->impl_ctx);

    // Free driver resources
    esp_task_wdt_impl_timer_free(p_twdt_obj->impl_ctx);

    // Free the global object
    free(p_twdt_obj);
    p_twdt_obj = NULL;

    return ESP_OK;

err:
    subscribe_idle(p_twdt_obj->idle_core_mask); // Resubscribe idle tasks
    return ret;
}

esp_err_t esp_task_wdt_add(TaskHandle_t task_handle)
{
    ESP_RETURN_ON_FALSE(p_twdt_obj != NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT was never initialized");
    esp_err_t ret;
    if (task_handle == NULL) {   // Get handle of current task if none is provided
        task_handle = xTaskGetCurrentTaskHandle();
    }

    twdt_entry_t *entry;
    ret = add_entry(true, (void *)task_handle, &entry);
    (void) entry; // Returned entry pointer not used
    return ret;
}

esp_err_t esp_task_wdt_add_user(const char *user_name, esp_task_wdt_user_handle_t *user_handle_ret)
{
    ESP_RETURN_ON_FALSE((user_name != NULL && user_handle_ret != NULL), ESP_ERR_INVALID_ARG, TAG, "Invalid arguments");
    ESP_RETURN_ON_FALSE(p_twdt_obj != NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT was never initialized");
    esp_err_t ret;
    twdt_entry_t *entry;
    ret = add_entry(false, (void *)user_name, &entry);
    if (ret == ESP_OK) {
        *user_handle_ret = (esp_task_wdt_user_handle_t)entry;
    }
    return ret;
}

esp_err_t esp_task_wdt_reset(void)
{
    ESP_RETURN_ON_FALSE(p_twdt_obj != NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT was never initialized");
    esp_err_t ret;
    TaskHandle_t handle = xTaskGetCurrentTaskHandle();

    portENTER_CRITICAL(&spinlock);
    // Find entry from task handle
    bool all_reset;
    twdt_entry_t *entry;
    entry = find_entry_from_task_handle_and_check_all_reset(handle, &all_reset);
    ESP_GOTO_ON_FALSE_ISR((entry != NULL), ESP_ERR_NOT_FOUND, err, TAG, "task not found");
    // Mark entry as reset and issue timer reset if all entries have been reset
    entry->has_reset = true;    // Reset the task if it's on the task list
    if (all_reset) {    // Reset if all other tasks in list have reset in
        task_wdt_timer_feed();
    }
    ret = ESP_OK;
err:
    portEXIT_CRITICAL(&spinlock);

    return ret;
}

esp_err_t esp_task_wdt_reset_user(esp_task_wdt_user_handle_t user_handle)
{
    ESP_RETURN_ON_FALSE(user_handle != NULL, ESP_ERR_INVALID_ARG, TAG, "Invalid arguments");
    ESP_RETURN_ON_FALSE(p_twdt_obj != NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT was never initialized");
    esp_err_t ret;

    portENTER_CRITICAL(&spinlock);
    // Check if entry exists
    bool all_reset;
    twdt_entry_t *entry = (twdt_entry_t *)user_handle;
    bool entry_found = find_entry_and_check_all_reset(entry, &all_reset);
    ESP_GOTO_ON_FALSE_ISR(entry_found, ESP_ERR_NOT_FOUND, err, TAG, "user handle not found");
    // Mark entry as reset and issue timer reset if all entries have been reset
    entry->has_reset = true;    // Reset the task if it's on the task list
    if (all_reset) {    // Reset if all other tasks in list have reset in
        task_wdt_timer_feed();
    }
    ret = ESP_OK;
err:
    portEXIT_CRITICAL(&spinlock);

    return ret;
}

esp_err_t esp_task_wdt_delete(TaskHandle_t task_handle)
{
    ESP_RETURN_ON_FALSE(p_twdt_obj != NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT was never initialized");
    esp_err_t ret;
    if (task_handle == NULL) {
        task_handle = xTaskGetCurrentTaskHandle();
    }

    ret = delete_entry(true, (void *)task_handle);
    return ret;
}

esp_err_t esp_task_wdt_delete_user(esp_task_wdt_user_handle_t user_handle)
{
    ESP_RETURN_ON_FALSE(user_handle != NULL, ESP_ERR_INVALID_ARG, TAG, "Invalid arguments");
    ESP_RETURN_ON_FALSE(p_twdt_obj != NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT was never initialized");
    return delete_entry(false, (void *)user_handle);
}

esp_err_t esp_task_wdt_status(TaskHandle_t task_handle)
{
    ESP_RETURN_ON_FALSE(p_twdt_obj != NULL, ESP_ERR_INVALID_STATE, TAG, "TWDT was never initialized");
    esp_err_t ret;
    if (task_handle == NULL) {
        task_handle = xTaskGetCurrentTaskHandle();
    }

    portENTER_CRITICAL(&spinlock);
    // Find entry for task
    bool all_reset;
    twdt_entry_t *entry;
    entry = find_entry_from_task_handle_and_check_all_reset(task_handle, &all_reset);
    (void) all_reset;   // Unused
    ret = (entry != NULL) ? ESP_OK : ESP_ERR_NOT_FOUND;
    portEXIT_CRITICAL(&spinlock);

    return ret;
}