esp-idf/components/app_trace/debug_stubs.c

/*
 * SPDX-FileCopyrightText: 2017-2023 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */

// This module implements debug/trace stubs. The stub is a piece of special code which can invoked by OpenOCD
// Currently one stub is used for GCOV functionality
//

#include "esp_private/startup_internal.h"
#include "dbg_stubs.h"
#include "esp_attr.h"

/*
    Debug stubs is actually a table of 4-byte entries. Every entry is equal to zero or must contain meaningfull data.
    The first entry is a service one and has the followinf format:
        - tramp_addr, 4 bytes; Address of buffer for trampoline/code. Max size is ESP_DBG_STUBS_CODE_BUF_SIZE.
        - min_stack_addr, 4 bytes; Start of the buffer for minimal onboard stack or data. Max size is ESP_DBG_STUBS_STACK_MIN_SIZE.
        - data_alloc, 4 bytes; Address of function to allocate memory on target.
        - data_free, 4 bytes; Address of function to free target memory.
    This entry is used by OpenOCD code to invoke other stub entries and allocate memory for them.
 */

#include "esp_log.h"
const static char *TAG = "esp_dbg_stubs";

#define ESP_DBG_STUBS_CODE_BUF_SIZE         32
#define ESP_DBG_STUBS_STACK_MIN_SIZE        2048

#define DBG_STUB_TRAMP_ATTR                 IRAM_ATTR

static struct {
    uint32_t    tramp_addr;
    uint32_t    min_stack_addr; // minimal stack addr
    uint32_t    data_alloc;
    uint32_t    data_free;
} s_dbg_stubs_ctl_data;

static uint32_t s_stub_entry[ESP_DBG_STUB_ENTRY_MAX];
static uint8_t s_stub_min_stack[ESP_DBG_STUBS_STACK_MIN_SIZE];
static DBG_STUB_TRAMP_ATTR uint8_t s_stub_code_buf[ESP_DBG_STUBS_CODE_BUF_SIZE];

extern void esp_dbg_stubs_ll_init(void *stub_table_addr);

// TODO: all called funcs should be in IRAM to work with disabled flash cache
static void * esp_dbg_stubs_data_alloc(uint32_t size)
{
    ESP_LOGV(TAG, "%s %"PRIu32, __func__, size);
    void *p = malloc(size);
    ESP_LOGV(TAG, "%s EXIT %p", __func__, p);
    return p;
}

static void esp_dbg_stubs_data_free(void *addr)
{
    ESP_LOGV(TAG, "%s %p", __func__, addr);
    free(addr);
}

void esp_dbg_stubs_init(void)
{
    s_dbg_stubs_ctl_data.tramp_addr     = (uint32_t)s_stub_code_buf;
    s_dbg_stubs_ctl_data.min_stack_addr = (uint32_t)s_stub_min_stack;
    s_dbg_stubs_ctl_data.data_alloc     = (uint32_t)esp_dbg_stubs_data_alloc;
    s_dbg_stubs_ctl_data.data_free      = (uint32_t)esp_dbg_stubs_data_free;

    s_stub_entry[ESP_DBG_STUB_MAGIC_NUM] = ESP_DBG_STUB_MAGIC_NUM_VAL;
    s_stub_entry[ESP_DBG_STUB_TABLE_SIZE] = ESP_DBG_STUB_ENTRY_MAX;
    s_stub_entry[ESP_DBG_STUB_CONTROL_DATA] = (uint32_t)&s_dbg_stubs_ctl_data;
    esp_dbg_stubs_ll_init(s_stub_entry);
}

// TODO: add lock mechanism. Not now but in the future ESP_DBG_STUB_ENTRY_CAPABILITIES can be set from different places.
esp_err_t esp_dbg_stub_entry_set(esp_dbg_stub_id_t id, uint32_t entry)
{
    if (id < ESP_DBG_STUB_ENTRY_FIRST || id >= ESP_DBG_STUB_ENTRY_MAX) {
        ESP_LOGE(TAG, "Invalid stub id %d!", id);
        return ESP_ERR_INVALID_ARG;
    }
    s_stub_entry[id] = entry;

    return ESP_OK;
}

esp_err_t esp_dbg_stub_entry_get(esp_dbg_stub_id_t id, uint32_t *entry)
{
    if (id < ESP_DBG_STUB_ENTRY_FIRST || id >= ESP_DBG_STUB_ENTRY_MAX) {
        ESP_LOGE(TAG, "Invalid stub id %d!", id);
        return ESP_ERR_INVALID_ARG;
    }
    *entry = s_stub_entry[id];

    return ESP_OK;
}

ESP_SYSTEM_INIT_FN(init_dbg_stubs, SECONDARY, BIT(0), 140)
{
    esp_dbg_stubs_init();
    return ESP_OK;
}