feat(esp_gdbstub): support watchpoint trigger reason

components/esp_gdbstub/private_include/esp_gdbstub_common.h

@@ -169,6 +169,15 @@ void esp_gdbstub_clear_step(void);
 void esp_gdbstub_do_step(esp_gdbstub_frame_t *regs_frame);
 void esp_gdbstub_trigger_cpu(void);
 
+#ifdef CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
+/**
+ * Check if a watchpoint triggered the current debug exception.
+ * @param[out] addr  Address of the triggered watchpoint (only valid if return is true)
+ * @return true if a watchpoint triggered, false otherwise (breakpoint/step/other)
+ */
+bool esp_gdbstub_get_watchpoint_trigger_addr(uint32_t *addr);
+#endif // CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
+
 /**
  * Write a value to register in frame
  * @param frame  gdbstub frame

components/esp_gdbstub/src/gdbstub.c

@@ -28,6 +28,10 @@
 #define GDBSTUB_QXFER_SUPPORTED_STR ""
 #endif
 
+#ifdef CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
+static void send_watchpoint_reason(void);
+#endif
+
 #ifdef CONFIG_ESP_GDBSTUB_SUPPORT_TASKS
 static inline int gdb_tid_to_task_index(int tid);
 static inline int task_index_to_gdb_tid(int tid);
@@ -110,6 +114,9 @@ static void send_reason(void)
     esp_gdbstub_send_start();
     esp_gdbstub_send_char('T');
     esp_gdbstub_send_hex(s_scratch.signal, 8);
+#ifdef CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
+    send_watchpoint_reason();
+#endif // CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
     esp_gdbstub_send_end();
 }
 
@@ -215,6 +222,35 @@ static bool not_send_reason = false;
 static bool process_gdb_kill = false;
 static bool gdb_debug_int = false;
 
+/**
+ * Detect if a watchpoint triggered and append the corresponding
+ * GDB RSP stop-reply field (watch/rwatch/awatch) to the current packet.
+ */
+static void send_watchpoint_reason(void)
+{
+    uint32_t wp_addr = 0;
+    if (!esp_gdbstub_get_watchpoint_trigger_addr(&wp_addr)) {
+        return;
+    }
+
+    const char *type_str = "watch";
+    for (size_t i = 0; i < SOC_CPU_WATCHPOINTS_NUM; i++) {
+        if (wp_list[i] == wp_addr) {
+            if (wp_access[i] == ESP_CPU_WATCHPOINT_LOAD) {
+                type_str = "rwatch";
+            } else if (wp_access[i] == ESP_CPU_WATCHPOINT_ACCESS) {
+                type_str = "awatch";
+            }
+            break;
+        }
+    }
+
+    esp_gdbstub_send_str(type_str);
+    esp_gdbstub_send_char(':');
+    esp_gdbstub_send_hex(wp_addr, 32);
+    esp_gdbstub_send_char(';');
+}
+
 /**
  * @brief Handle UART interrupt
  *

components/esp_gdbstub/src/port/riscv/gdbstub_riscv.c

@@ -250,6 +250,22 @@ void esp_gdbstub_init_dports(void)
 {
 }
 
+bool esp_gdbstub_get_watchpoint_trigger_addr(uint32_t *addr)
+{
+    for (int i = 0; i < SOC_CPU_BREAKPOINTS_NUM; i++) {
+        RV_WRITE_CSR(tselect, i);
+        uint32_t tdata1 = RV_READ_CSR(tdata1);
+        bool is_load = tdata1 & TDATA1_LOAD;
+        bool is_store = tdata1 & TDATA1_STORE;
+        bool is_exec = tdata1 & TDATA1_EXECUTE;
+        if (!is_exec && (is_load || is_store)) {
+            *addr = RV_READ_CSR(tdata2);
+            return true;
+        }
+    }
+    return false;
+}
+
 #endif // CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
 
 #if (!CONFIG_ESP_SYSTEM_SINGLE_CORE_MODE) && CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME

components/esp_gdbstub/src/port/xtensa/gdbstub_xtensa.c

@@ -307,6 +307,23 @@ void esp_gdbstub_init_dports(void)
 {
 }
 
+#ifdef CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
+bool esp_gdbstub_get_watchpoint_trigger_addr(uint32_t *addr)
+{
+    uint32_t debugcause;
+    RSR(XT_REG_DEBUGCAUSE, debugcause);
+    if (debugcause & XCHAL_DEBUGCAUSE_DBREAK_MASK) {
+        if (debugcause & (1 << 8)) {
+            RSR(XT_REG_DBREAKA_1, *addr);
+        } else {
+            RSR(XT_REG_DBREAKA_0, *addr);
+        }
+        return true;
+    }
+    return false;
+}
+#endif // CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
+
 #if CONFIG_IDF_TARGET_ARCH_XTENSA && (!CONFIG_ESP_SYSTEM_SINGLE_CORE_MODE) && CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
 static bool stall_started = false;
 #endif

tools/test_apps/system/gdbstub_runtime/pytest_gdbstub_runtime.py

@@ -371,14 +371,11 @@ def test_gdbstub_runtime(dut: PanicTestDut) -> None:
     assert dut.find_gdb_response('done', 'result', responses) is not None
     cmd = '-exec-continue'
     payload = run_and_break(dut, cmd)
-    assert payload['reason'] == 'signal-received'
+    assert payload['reason'] == 'watchpoint-trigger'
+    assert int(payload['value']['new']) == int(payload['value']['old']) + 2
     assert payload['frame']['func'] == 'foo'
+    assert payload['frame']['line'] == str(get_line_number('var_2--;'))
     assert payload['stopped-threads'] == 'all'
-    # Uncomment this when implement send reason to gdb: GCC-313
-    #
-    # assert payload['reason'] == 'watchpoint-trigger'
-    # assert int(payload['value']['new']) == int(payload['value']['old']) + 1
-    # assert payload['frame']['line'] == '14'
 
     cmd = '-break-delete 2'
     responses = dut.gdb_write(cmd)