ANDROID: Add kunit targets.

The kunit targets build in-tree kunit modules with a pre-set
defconfig fragment.

This is the defconfig fragment to be applied to enable kunit tests
as modules. Because we apply defconfig fragments after running
make defconfig, the individual tests must be enabled instead of
a global CONFIG_KUNIT_ALL_TESTS flag.

Note: Comparing to the change on android-mainline, this change
deletes the following tests because they do not present in
android14-5.15:

  CONFIG_NETDEV_ADDR_LIST_TEST
  CONFIG_REGMAP_KUNIT
  CONFIG_INPUT_KUNIT_TEST
  CONFIG_SND_SOC_UTILS_KUNIT_TEST
  CONFIG_HID_KUNIT_TEST
  CONFIG_IIO_FORMAT_KUNIT_TEST
  CONFIG_CLK_KUNIT_TEST
  CONFIG_CLK_GATE_KUNIT_TEST

Comparing to the change on android-mainline, this change
adds a symbol list for kunit tests. To update this symbol list:

  bazel run //common:kunit_aarch64_abi_update_symbol_list

Comparing to the change on android-mainline, this change
does not contain a target for riscv64.

Test: manually build with
  bazel run //common:kunit_aarch64_dist
  bazel run //common:kunit_x86_64_dist
  bazel run //common:kunit_riscv64_dist
Bug: 296116800
Bug: 304616548
Bug: 305290382
Change-Id: If3b94f495aa64b657508781b12e3e0716c725f3f
Signed-off-by: Yifan Hong <elsk@google.com>

BUILD.bazel

@@ -96,6 +96,7 @@ filegroup(
         "android/abi_gki_aarch64_db845c",
         "android/abi_gki_aarch64_exynos",
         "android/abi_gki_aarch64_fips140",
+        "android/abi_gki_aarch64_kunit",
         "android/abi_gki_aarch64_lenovo",
         "android/abi_gki_aarch64_mtkott",
         "android/abi_gki_aarch64_mtktv",
@@ -614,6 +615,70 @@ kernel_build(
     visibility = ["//visibility:private"],
 )
 
+# KUnit test targets
+
+# Modules defined by tools/testing/kunit/configs/android/kunit_defconfig
+_KUNIT_COMMON_MODULES = [
+    # keep sorted
+    "drivers/rtc/lib_test.ko",
+    "fs/ext4/ext4-inode-test.ko",
+    "fs/fat/fat_test.ko",
+    "kernel/time/time_test.ko",
+    "lib/kunit/kunit-example-test.ko",
+    "lib/kunit/kunit-test.ko",
+    "mm/kfence/kfence_test.ko",
+    "sound/soc/soc-topology-test.ko",
+]
+
+kernel_build(
+    name = "kunit_aarch64",
+    outs = [],
+    arch = "arm64",
+    base_kernel = ":kernel_aarch64",
+    build_config = "build.config.kunit.aarch64",
+    defconfig_fragments = [
+        "tools/testing/kunit/configs/android/kunit_defconfig",
+    ],
+    kmi_symbol_list = "android/abi_gki_aarch64_kunit",
+    make_goals = ["modules"],
+    module_outs = _KUNIT_COMMON_MODULES,
+)
+
+copy_to_dist_dir(
+    name = "kunit_aarch64_dist",
+    data = [":kunit_aarch64"],
+    dist_dir = "out/kunit_aarch64/dist",
+    flat = True,
+    log = "info",
+)
+
+kernel_abi(
+    name = "kunit_aarch64_abi",
+    kernel_build = ":kunit_aarch64",
+    kmi_symbol_list_add_only = True,
+)
+
+kernel_build(
+    name = "kunit_x86_64",
+    outs = [],
+    arch = "x86_64",
+    base_kernel = ":kernel_x86_64",
+    build_config = "build.config.kunit.x86_64",
+    defconfig_fragments = [
+        "tools/testing/kunit/configs/android/kunit_defconfig",
+    ],
+    make_goals = ["modules"],
+    module_outs = _KUNIT_COMMON_MODULES,
+)
+
+copy_to_dist_dir(
+    name = "kunit_x86_64_dist",
+    data = [":kunit_x86_64"],
+    dist_dir = "out/kunit_x86_64/dist",
+    flat = True,
+    log = "info",
+)
+
 # DDK Headers
 # All headers. These are the public targets for DDK modules to use.
 alias(

android/abi_gki_aarch64_kunit

@@ -0,0 +1,94 @@
+[abi_symbol_list]
+# commonly used symbols
+  kfree
+  kmalloc_caches
+  kunit_binary_assert_format
+  kunit_do_assertion
+  kunit_fail_assert_format
+  kunit_kmalloc_array
+  kunit_log_append
+  kunit_ptr_not_err_assert_format
+  __kunit_test_suites_exit
+  __kunit_test_suites_init
+  kunit_try_catch_throw
+  kunit_unary_assert_format
+  memset
+  module_layout
+  _printk
+  __put_task_struct
+  _raw_spin_lock_irqsave
+  _raw_spin_unlock_irqrestore
+  scnprintf
+  __stack_chk_fail
+  strcmp
+  strscpy
+  __ubsan_handle_cfi_check_fail_abort
+
+# required by fat_test.ko
+  fat_time_fat2unix
+  fat_time_unix2fat
+
+# required by kfence_test.ko
+  for_each_kernel_tracepoint
+  jiffies
+  kasan_flag_enabled
+  __kfence_pool
+  __kmalloc
+  kmem_cache_alloc
+  kmem_cache_alloc_bulk
+  kmem_cache_create
+  kmem_cache_destroy
+  kmem_cache_free
+  kmem_cache_free_bulk
+  kmem_cache_shrink
+  krealloc
+  ksize
+  prandom_u32
+  rcu_barrier
+  __rcu_read_lock
+  __rcu_read_unlock
+  strchr
+  strnstr
+  strstr
+  synchronize_rcu
+  synchronize_srcu
+  tracepoint_probe_register
+  tracepoint_probe_unregister
+  tracepoint_srcu
+
+# required by kunit-test.ko
+  arm64_const_caps_ready
+  __cfi_slowpath_diag
+  cpu_hwcap_keys
+  kmem_cache_alloc_trace
+  kunit_add_named_resource
+  kunit_add_resource
+  kunit_alloc_and_get_resource
+  kunit_binary_ptr_assert_format
+  kunit_binary_str_assert_format
+  kunit_cleanup
+  kunit_destroy_resource
+  kunit_init_test
+  kunit_try_catch_run
+  refcount_warn_saturate
+
+# required by lib_test.ko
+  rtc_month_days
+  rtc_time64_to_tm
+
+# required by soc-topology-test.ko
+  get_device
+  memcpy
+  put_device
+  __root_device_register
+  root_device_unregister
+  snd_soc_add_component
+  snd_soc_component_initialize
+  snd_soc_register_card
+  snd_soc_tplg_component_load
+  snd_soc_tplg_component_remove
+  snd_soc_unregister_card
+  snd_soc_unregister_component
+
+# required by time_test.ko
+  time64_to_tm

build.config.kunit.aarch64

@@ -0,0 +1,4 @@
+. ${ROOT_DIR}/${KERNEL_DIR}/build.config.common
+. ${ROOT_DIR}/${KERNEL_DIR}/build.config.aarch64
+
+DEFCONFIG=gki_defconfig

build.config.kunit.x86_64

@@ -0,0 +1,4 @@
+. ${ROOT_DIR}/${KERNEL_DIR}/build.config.common
+. ${ROOT_DIR}/${KERNEL_DIR}/build.config.x86_64
+
+DEFCONFIG=gki_defconfig

tools/testing/kunit/configs/android/kunit_defconfig

@@ -0,0 +1,31 @@
+# Defconfig fragment for Android Kunit targets
+#
+# Instead of setting CONFIG_KUNIT_ALL_TESTS=m, we enable individual tests
+# because:
+# - The defconfig fragment is applied after make defconfig
+# - If additional tests are added to CONFIG_KUNIT_ALL_TESTS in the future,
+#   //common:kunit_* module_outs needs to be updated.
+
+# CONFIG_MODULE_SIG_ALL is not set
+
+# Corresponds to BUILD.bazel, _KUNIT_COMMON_MODULES
+CONFIG_TIME_KUNIT_TEST=m
+CONFIG_SND_SOC_TOPOLOGY_KUNIT_TEST=m
+CONFIG_RTC_LIB_KUNIT_TEST=m
+CONFIG_EXT4_KUNIT_TESTS=m
+CONFIG_FAT_KUNIT_TEST=m
+CONFIG_KFENCE_KUNIT_TEST=m
+CONFIG_KUNIT_TEST=m
+CONFIG_KUNIT_EXAMPLE_TEST=m
+
+# CONFIG_NET_HANDSHAKE is not enabled in gki_defconfig.
+# CONFIG_NET_HANDSHAKE_KUNIT_TEST=m
+
+# TODO(b/296116800): Enable these tests
+# CONFIG_DRM_KUNIT_TEST=m
+# CONFIG_KASAN_KUNIT_TEST=m
+
+# TODO(b/296116800): These are booleans, not tristates.
+# CONFIG_BINFMT_ELF_KUNIT_TEST=y
+# CONFIG_PM_QOS_KUNIT_TEST=y
+# CONFIG_DRIVER_PE_KUNIT_TEST=y