diff --git a/components/esp_system/dbg_stubs.c b/components/esp_system/dbg_stubs.c
new file mode 100644
index 0000000000..1ee9124897
--- /dev/null
+++ b/components/esp_system/dbg_stubs.c
@@ -0,0 +1,95 @@
+// Copyright 2017 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// 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 "eri.h"
+#include "xtensa-debug-module.h"
+#include "esp_private/dbg_stubs.h"
+#include "esp_attr.h"
+
+#if CONFIG_ESP_DEBUG_STUBS_ENABLE
+/*
+    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.
+ */
+
+#define LOG_LOCAL_LEVEL CONFIG_LOG_DEFAULT_LEVEL
+#include "esp_log.h"
+const static char *TAG = "esp_dbg_stubs";
+
+#define ESP_DBG_STUBS_TRAX_REG              ERI_TRAX_TRIGGERPC
+#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];
+
+// 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 %d", __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);
+    ESP_LOGV(TAG, "%s EXIT %p", __func__, 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_CONTROL_DATA] = (uint32_t)&s_dbg_stubs_ctl_data;
+    eri_write(ESP_DBG_STUBS_TRAX_REG, (uint32_t)s_stub_entry);
+    ESP_LOGV(TAG, "%s stubs %x", __func__, eri_read(ESP_DBG_STUBS_TRAX_REG));
+}
+
+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;
+}
+
+#endif