Merge branch 'bugfix/esp32c2_missing_eh_frame_sections' into 'master'

espsystem: add missing eh_frame sections on esp32c2

See merge request espressif/esp-idf!18629

components/esp_system/ld/esp32c2/memory.ld.in

@@ -96,3 +96,8 @@ _heap_end = 0x40000000;
   ASSERT(_flash_rodata_dummy_start == ORIGIN(default_rodata_seg),
          ".flash_rodata_dummy section must be placed at the beginning of the rodata segment.")
 #endif
+
+#if CONFIG_ESP_SYSTEM_USE_EH_FRAME
+    ASSERT ((__eh_frame_end > __eh_frame), "Error: eh_frame size is null!");
+    ASSERT ((__eh_frame_hdr_end > __eh_frame_hdr), "Error: eh_frame_hdr size is null!");
+#endif

components/esp_system/ld/esp32c2/sections.ld.in

@@ -175,9 +175,6 @@ SECTIONS
     *(.gcc_except_table .gcc_except_table.*)
     *(.gnu.linkonce.e.*)
     *(.gnu.version_r)
-    . = (. + 3) & ~ 3;
-    __eh_frame = ABSOLUTE(.);
-    KEEP(*(.eh_frame))
     . = (. + 7) & ~ 3;
     /*
      * C++ constructor and destructor tables
@@ -226,7 +223,27 @@ SECTIONS
     *(.tbss.*)
     _thread_local_end = ABSOLUTE(.);
     _rodata_reserved_end = ABSOLUTE(.);
-    . = ALIGN(4);
+    . = ALIGN(ALIGNOF(.eh_frame));
+  } > default_rodata_seg
+
+  /* Keep this section shall be at least aligned on 4 */
+  .eh_frame : ALIGN(8)
+  {
+    __eh_frame = ABSOLUTE(.);
+    KEEP (*(.eh_frame))
+    __eh_frame_end = ABSOLUTE(.);
+    /* Guarantee that this section and the next one will be merged by making
+     * them adjacent. */
+    . = ALIGN(ALIGNOF(.eh_frame_hdr));
+  } > default_rodata_seg
+
+  /* To avoid any exception in C++ exception frame unwinding code, this section
+   * shall be aligned on 8. */
+  .eh_frame_hdr : ALIGN(8)
+  {
+    __eh_frame_hdr = ABSOLUTE(.);
+    KEEP (*(.eh_frame_hdr))
+    __eh_frame_hdr_end = ABSOLUTE(.);
   } > default_rodata_seg
 
   .flash.rodata_noload (NOLOAD) :

tools/test_apps/system/eh_frame/CMakeLists.txt

@@ -0,0 +1,6 @@
+# The following lines of boilerplate have to be in your project's CMakeLists
+# in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(eh_frame)

tools/test_apps/system/eh_frame/README.md

@@ -0,0 +1,16 @@
+| Supported Targets | ESP32-C3 | ESP32-H2 | ESP32-C2 |
+| ----------------- | -------- | -------- | -------- |
+
+# Building and running
+
+The main goal of this test is to check whether the compiler/linker generates non-empty sections `.eh_frame` and `.eh_frame_hdr`.
+ 
+Thus, as soon as this example compiles we can considered it passed. However, it will also print the addresses of both sections on the UART.
+
+In order to build and run the example, use the following commands:
+
+```
+idf.py set-target <esp32c3/esp32h2/esp32c2>
+idf.py build
+idf.py flash monitor
+``` 

tools/test_apps/system/eh_frame/main/CMakeLists.txt

@@ -0,0 +1,3 @@
+idf_component_register(SRCS "eh_frame_main.c"
+                       INCLUDE_DIRS "."
+                       REQUIRES esp_system)

tools/test_apps/system/eh_frame/main/eh_frame_main.c

@@ -0,0 +1,40 @@
+/*
+ * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <assert.h>
+#include <string.h>
+
+/**
+ * @brief Symbols defined by the linker.
+ * Retrieve the addresses of both .eh_frame_hdr and .eh_frame sections.
+ */
+extern char __eh_frame_hdr;
+extern char __eh_frame_hdr_end;
+extern char __eh_frame;
+extern char __eh_frame_end;
+
+/**
+ * @brief Pointers to both .eh_frame_hdr and .eh_frame sections.
+ */
+#define EH_FRAME_HDR_ADDR       ((void*) (&__eh_frame_hdr))
+#define EH_FRAME_HDR_END_ADDR   ((void*) (&__eh_frame_hdr_end))
+#define EH_FRAME_ADDR           ((void*) (&__eh_frame))
+#define EH_FRAME_END_ADDR       ((void*) (&__eh_frame_end))
+
+
+void app_main(void)
+{
+    /* As soon as this test compiles, it can be considered passed. The linker should
+     * test that the eh_frame and eh_frame_hdr sections are not empty but let's make
+     * sure again that they are not empty. */
+    assert((EH_FRAME_END_ADDR > EH_FRAME_ADDR) && ".eh_frame section must not be empty");
+    assert((EH_FRAME_HDR_END_ADDR > EH_FRAME_HDR_ADDR) && ".eh_frame_hdr section must not be empty");
+
+    /* Use the symbols just to make sure they won't be optimized away */
+    printf(".eh_frame start: %p, end: %p\n", EH_FRAME_ADDR, EH_FRAME_END_ADDR);
+    printf(".eh_frame_hdr start: %p, end: %p\n", EH_FRAME_HDR_ADDR, EH_FRAME_HDR_END_ADDR);
+}

tools/test_apps/system/eh_frame/sdkconfig.defaults

@@ -0,0 +1,2 @@
+# Enable eh_frame sections generation
+CONFIG_ESP_SYSTEM_USE_EH_FRAME=y