test(esp_common): Add Linux host test for portable section macros

Add a test app that verifies PLACE_IN_SECTION, _SECTION_ATTR_SYMBOL_DECL_GENERIC,
_SECTION_START and _SECTION_END macros work correctly on Linux.

The test places 5 uint32_t values into a custom .test_data_table section from
two separate translation units, then iterates the section at runtime to verify
the correct count and content of all entries.

Includes:
- Custom linker script (ld/test_section.ld)
- Build-test-rules entry (linux only)
- pytest host_test marker

components/esp_common/include/esp_attr.h

@@ -248,13 +248,13 @@ FORCE_INLINE_ATTR TYPE& operator<<=(TYPE& a, int b) { a = a << b; return a; }
 #if defined(__APPLE__) && defined(__MACH__)
 /* ---------- macOS (Mach-O) ---------- */
 #include <mach-o/getsect.h>
+#include <mach-o/ldsyms.h>
 #include <mach-o/dyld.h>
 
-#define PLACE_IN_SECTION(SECTION) \
+#define _SECTION_ATTR_IMPL_GENERIC(SECTION, COUNTER) \
     __attribute__((used, aligned(4), section("__DATA," SECTION)))
 
-#define _SECTION_ATTR_IMPL_GENERIC(SECTION, COUNTER) \
-    __attribute__((aligned(4), section("__DATA," SECTION)))
+#define PLACE_IN_SECTION(SECTION) _SECTION_ATTR_IMPL_GENERIC(SECTION, __COUNTER__)
 
 #define _SECTION_ATTR_SYMBOL_DECL_GENERIC(TYPE, SECTION_NAME) \
     static const TYPE *_##SECTION_NAME##_start_ptr; \
@@ -278,11 +278,10 @@ FORCE_INLINE_ATTR TYPE& operator<<=(TYPE& a, int b) { a = a << b; return a; }
 
 #else /* ELF targets (Linux and embedded) */
 
-#define PLACE_IN_SECTION(SECTION) \
-    __attribute__((used, aligned(4), section("." SECTION)))
-
 #define _SECTION_ATTR_IMPL_GENERIC(SECTION, COUNTER) \
-    __attribute__((aligned(4), section("." SECTION "." _COUNTER_STRINGIFY(COUNTER))))
+    __attribute__((used, aligned(4), section("." SECTION "." _COUNTER_STRINGIFY(COUNTER))))
+
+#define PLACE_IN_SECTION(SECTION) _SECTION_ATTR_IMPL_GENERIC(SECTION, __COUNTER__)
 
 #define _SECTION_ATTR_SYMBOL_DECL_GENERIC(TYPE, SECTION_NAME) \
     extern TYPE _##SECTION_NAME##_start; \

components/esp_common/test_apps/.build-test-rules.yml

@@ -8,3 +8,9 @@ components/esp_common/test_apps/esp_common:
   depends_components:
     - esp_common
     - esp_system # Defines the section placement for attributes
+
+components/esp_common/test_apps/section_macros:
+  enable:
+    - if: IDF_TARGET == "linux"
+  depends_components:
+    - esp_common

components/esp_common/test_apps/section_macros/CMakeLists.txt

@@ -0,0 +1,10 @@
+# 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 3.22)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+# "Trim" the build. Include the minimal set of components, main, and anything it depends on.
+set(COMPONENTS main)
+
+project(test_section_macros)

components/esp_common/test_apps/section_macros/ld/test_section.ld

@@ -0,0 +1,19 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Linker script for the section macros test on Linux host builds.
+ * Collects all uint32_t entries placed in the .test_data_table section.
+ */
+
+SECTIONS
+{
+    .test_data_table :
+    {
+        PROVIDE(_test_data_table_start = .);
+        KEEP(*(SORT(.test_data_table*)))
+        PROVIDE(_test_data_table_end = .);
+    }
+}
+INSERT AFTER .data;

components/esp_common/test_apps/section_macros/main/CMakeLists.txt

@@ -0,0 +1,11 @@
+idf_component_register(SRCS "test_section_macros.c" "test_entries_a.c" "test_entries_b.c"
+                       INCLUDE_DIRS "."
+                       WHOLE_ARCHIVE)
+
+if(CONFIG_IDF_TARGET_LINUX AND NOT CMAKE_HOST_SYSTEM_NAME STREQUAL "Darwin")
+    # Add linker script that collects the .test_data_table section
+    # On macOS, custom sections are handled via Mach-O __DATA segments
+    # and do not require linker scripts (which use GNU ld -T syntax).
+    target_link_options(${COMPONENT_LIB} INTERFACE
+        "-Wl,-T,${CMAKE_CURRENT_LIST_DIR}/../ld/test_section.ld")
+endif()

components/esp_common/test_apps/section_macros/main/test_entries_a.c

@@ -0,0 +1,16 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "esp_attr.h"
+#include <stdint.h>
+
+/*
+ * Three entries placed in the test_data_table section from translation unit A.
+ * The test verifies these values are discoverable at link time.
+ */
+static const uint32_t entry_a1 PLACE_IN_SECTION("test_data_table") = 0xDEADBEEF;
+static const uint32_t entry_a2 PLACE_IN_SECTION("test_data_table") = 0xCAFEBABE;
+static const uint32_t entry_a3 PLACE_IN_SECTION("test_data_table") = 0x12345678;

components/esp_common/test_apps/section_macros/main/test_entries_b.c

@@ -0,0 +1,16 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "esp_attr.h"
+#include <stdint.h>
+
+/*
+ * Two entries placed in the test_data_table section from a DIFFERENT
+ * translation unit.  This verifies the linker collects entries across
+ * multiple object files.
+ */
+static const uint32_t entry_b1 PLACE_IN_SECTION("test_data_table") = 0xAAAAAAAA;
+static const uint32_t entry_b2 PLACE_IN_SECTION("test_data_table") = 0x55555555;

components/esp_common/test_apps/section_macros/main/test_section_macros.c

@@ -0,0 +1,81 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include "esp_attr.h"
+
+/*
+ * Test for the portable link-time section macros defined in esp_attr.h.
+ *
+ * Two separate translation units (test_entries_a.c and test_entries_b.c)
+ * place uint32_t values into the "test_data_table" section using
+ * PLACE_IN_SECTION().  This main function uses _SECTION_ATTR_SYMBOL_DECL_GENERIC
+ * and _SECTION_START/_SECTION_END to iterate the collected entries and verify:
+ *   1. The total count matches the expected number (5 entries).
+ *   2. Every expected value is present in the section.
+ */
+
+_SECTION_ATTR_SYMBOL_DECL_GENERIC(uint32_t, test_data_table)
+
+/* Expected values — order is linker-determined, so we check membership */
+static const uint32_t expected_values[] = {
+    0xDEADBEEF,
+    0xCAFEBABE,
+    0x12345678,
+    0xAAAAAAAA,
+    0x55555555,
+};
+
+#define EXPECTED_COUNT (sizeof(expected_values) / sizeof(expected_values[0]))
+
+void app_main(void)
+{
+    const uint32_t *start = _SECTION_START(test_data_table);
+    const uint32_t *end   = _SECTION_END(test_data_table);
+
+    /* --- Check 1: entry count -------------------------------------------- */
+    size_t count = (size_t)(end - start);
+    printf("Section entry count: %zu (expected %zu)\n", count, (size_t)EXPECTED_COUNT);
+
+    if (count != EXPECTED_COUNT) {
+        printf("FAIL: entry count mismatch\n");
+        exit(1);
+    }
+
+    /* --- Check 2: every expected value is present ------------------------ */
+    for (size_t i = 0; i < EXPECTED_COUNT; i++) {
+        int found = 0;
+        for (size_t j = 0; j < count; j++) {
+            if (start[j] == expected_values[i]) {
+                found = 1;
+                break;
+            }
+        }
+        if (!found) {
+            printf("FAIL: expected value 0x%08X not found in section\n", expected_values[i]);
+            exit(1);
+        }
+    }
+
+    /* --- Check 3: no unexpected values ----------------------------------- */
+    for (size_t j = 0; j < count; j++) {
+        int known = 0;
+        for (size_t i = 0; i < EXPECTED_COUNT; i++) {
+            if (start[j] == expected_values[i]) {
+                known = 1;
+                break;
+            }
+        }
+        if (!known) {
+            printf("FAIL: unexpected value 0x%08X found in section\n", start[j]);
+            exit(1);
+        }
+    }
+
+    printf("SUCCESS: All %zu section entries verified.\n", count);
+}

components/esp_common/test_apps/section_macros/pytest_section_macros.py

@@ -0,0 +1,19 @@
+# SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: Apache-2.0
+
+import pytest
+from pytest_embedded import Dut
+from pytest_embedded_idf.utils import idf_parametrize
+
+
+@pytest.mark.host_test
+@idf_parametrize('target', ['linux'], indirect=['target'])
+def test_section_macros(dut: Dut) -> None:
+    dut.expect('SUCCESS: All 5 section entries verified.')
+
+
+@pytest.mark.host_test
+@pytest.mark.macos
+@idf_parametrize('target', ['linux'], indirect=['target'])
+def test_section_macros_macos(dut: Dut) -> None:
+    dut.expect('SUCCESS: All 5 section entries verified.')

components/esp_common/test_apps/section_macros/sdkconfig.defaults

@@ -0,0 +1 @@
+CONFIG_IDF_TARGET="linux"