KUnit has several macros and functions intended for use from non-test code. These hooks, currently the kunit_get_current_test() and kunit_fail_current_test() macros, didn't work when CONFIG_KUNIT=m. In order to support this case, the required functions and static data need to be available unconditionally, even when KUnit itself is not built-in. The new 'hooks.c' file is therefore always included, and has both the static key required for kunit_get_current_test(), and a function pointer to the real implementation of __kunit_fail_current_test(), which is populated when the KUnit module is loaded. This can then be extended for future features which require similar "hook" behaviour, such as static stubs: https://lore.kernel.org/all/20221208061841.2186447-1-davidgow@xxxxxxxxxx/ Signed-off-by: David Gow <davidgow@xxxxxxxxxx> --- This is basically a prerequisite for the stub features working when KUnit is built as a module, and should nicely make a few other tests work then, too. I'm not 100% sold on the whole "fill in a table of function pointers when kunit.ko is loaded" trick: it is basically just working around the sensible limitations on depending on modules. I think it should be safe here, as the functions/macros all have fallback behaviour when no test is running, and this is just another case of that. Similarly, I'm sure there must be a better way to compile hooks.o in when KUNIT=y or KUNIT=m, but the trick of adding it separately as an obj-y in the lib/ Makefile, then having an #if IS_ENABLED() check in the file is the only one I've been able to come up with using my meagre knowledge of Kbuild. Better suggestions welcome! --- Documentation/dev-tools/kunit/usage.rst | 14 ++++++-------- include/kunit/test-bug.h | 15 ++++++++------- lib/Makefile | 4 ++++ lib/kunit/Makefile | 3 +++ lib/kunit/hooks.c | 23 +++++++++++++++++++++++ lib/kunit/test.c | 10 ++++------ 6 files changed, 48 insertions(+), 21 deletions(-) create mode 100644 lib/kunit/hooks.c diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst index 48f8196d5aad..6424493b93cb 100644 --- a/Documentation/dev-tools/kunit/usage.rst +++ b/Documentation/dev-tools/kunit/usage.rst @@ -648,10 +648,9 @@ We can do this via the ``kunit_test`` field in ``task_struct``, which we can access using the ``kunit_get_current_test()`` function in ``kunit/test-bug.h``. ``kunit_get_current_test()`` is safe to call even if KUnit is not enabled. If -KUnit is not enabled, was built as a module (``CONFIG_KUNIT=m``), or no test is -running in the current task, it will return ``NULL``. This compiles down to -either a no-op or a static key check, so will have a negligible performance -impact when no test is running. +KUnit is not enabled, or if no test is running in the current task, it will +return ``NULL``. This compiles down to either a no-op or a static key check, +so will have a negligible performance impact when no test is running. The example below uses this to implement a "mock" implementation of a function, ``foo``: @@ -726,8 +725,7 @@ structures as shown below: #endif ``kunit_fail_current_test()`` is safe to call even if KUnit is not enabled. If -KUnit is not enabled, was built as a module (``CONFIG_KUNIT=m``), or no test is -running in the current task, it will do nothing. This compiles down to either a -no-op or a static key check, so will have a negligible performance impact when -no test is running. +KUnit is not enabled, or if no test is running in the current task, it will do +nothing. This compiles down to either a no-op or a static key check, so will +have a negligible performance impact when no test is running. diff --git a/include/kunit/test-bug.h b/include/kunit/test-bug.h index c1b2e14eab64..122f50198903 100644 --- a/include/kunit/test-bug.h +++ b/include/kunit/test-bug.h @@ -1,6 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0 */ /* - * KUnit API allowing dynamic analysis tools to interact with KUnit tests + * KUnit API providing hooks for non-test code to interact with tests. * * Copyright (C) 2020, Google LLC. * Author: Uriel Guajardo <urielguajardo@xxxxxxxxxx> @@ -9,7 +9,7 @@ #ifndef _KUNIT_TEST_BUG_H #define _KUNIT_TEST_BUG_H -#if IS_BUILTIN(CONFIG_KUNIT) +#if IS_ENABLED(CONFIG_KUNIT) #include <linux/jump_label.h> /* For static branch */ #include <linux/sched.h> @@ -43,20 +43,21 @@ static inline struct kunit *kunit_get_current_test(void) * kunit_fail_current_test() - If a KUnit test is running, fail it. * * If a KUnit test is running in the current task, mark that test as failed. - * - * This macro will only work if KUnit is built-in (though the tests - * themselves can be modules). Otherwise, it compiles down to nothing. */ #define kunit_fail_current_test(fmt, ...) do { \ if (static_branch_unlikely(&kunit_running)) { \ + /* Guaranteed to be non-NULL when kunit_running true*/ \ __kunit_fail_current_test(__FILE__, __LINE__, \ fmt, ##__VA_ARGS__); \ } \ } while (0) -extern __printf(3, 4) void __kunit_fail_current_test(const char *file, int line, - const char *fmt, ...); +/* Function pointer defined as a hook in hooks.c, and implemented in test.c */ +typedef __printf(3, 4) void kunit_hook_fn_fail_current_test(const char *file, + int line, + const char *fmt, ...); +extern kunit_hook_fn_fail_current_test *__kunit_fail_current_test; #else diff --git a/lib/Makefile b/lib/Makefile index 4d9461bfea42..9031de6ca73c 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -126,6 +126,10 @@ CFLAGS_test_fpu.o += $(FPU_CFLAGS) obj-$(CONFIG_TEST_LIVEPATCH) += livepatch/ obj-$(CONFIG_KUNIT) += kunit/ +# Include the KUnit hooks unconditionally. They'll compile to nothing if +# CONFIG_KUNIT=n, otherwise will be a small table of static data (static key, +# function pointers) which need to be built-in even when KUnit is a module. +obj-y += kunit/hooks.o ifeq ($(CONFIG_DEBUG_KOBJECT),y) CFLAGS_kobject.o += -DDEBUG diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile index 29aff6562b42..deeb46cc879b 100644 --- a/lib/kunit/Makefile +++ b/lib/kunit/Makefile @@ -11,6 +11,9 @@ ifeq ($(CONFIG_KUNIT_DEBUGFS),y) kunit-objs += debugfs.o endif +# KUnit 'hooks' are built-in even when KUnit is built as a module. +lib-y += hooks.o + obj-$(CONFIG_KUNIT_TEST) += kunit-test.o # string-stream-test compiles built-in only. diff --git a/lib/kunit/hooks.c b/lib/kunit/hooks.c new file mode 100644 index 000000000000..48189567a774 --- /dev/null +++ b/lib/kunit/hooks.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit 'Hooks' implementation. + * + * This file contains code / structures which should be built-in even when + * KUnit itself is built as a module. + * + * Copyright (C) 2022, Google LLC. + * Author: David Gow <davidgow@xxxxxxxxxx> + */ + +/* This file is always built-in, so make sure it's empty if CONFIG_KUNIT=n */ +#if IS_ENABLED(CONFIG_KUNIT) + +#include <kunit/test-bug.h> + +DEFINE_STATIC_KEY_FALSE(kunit_running); +EXPORT_SYMBOL(kunit_running); + +/* Function pointers for hooks. */ +kunit_hook_fn_fail_current_test *__kunit_fail_current_test; +EXPORT_SYMBOL_GPL(__kunit_fail_current_test); +#endif diff --git a/lib/kunit/test.c b/lib/kunit/test.c index c9ebf975e56b..711fdcce6de8 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -20,13 +20,10 @@ #include "string-stream.h" #include "try-catch-impl.h" -DEFINE_STATIC_KEY_FALSE(kunit_running); - -#if IS_BUILTIN(CONFIG_KUNIT) /* * Fail the current test and print an error message to the log. */ -void __kunit_fail_current_test(const char *file, int line, const char *fmt, ...) +void __kunit_fail_current_test_impl(const char *file, int line, const char *fmt, ...) { va_list args; int len; @@ -53,8 +50,6 @@ void __kunit_fail_current_test(const char *file, int line, const char *fmt, ...) kunit_err(current->kunit_test, "%s:%d: %s", file, line, buffer); kunit_kfree(current->kunit_test, buffer); } -EXPORT_SYMBOL_GPL(__kunit_fail_current_test); -#endif /* * Enable KUnit tests to run. @@ -777,6 +772,9 @@ EXPORT_SYMBOL_GPL(kunit_cleanup); static int __init kunit_init(void) { + /* Install the KUnit hook functions. */ + __kunit_fail_current_test = __kunit_fail_current_test_impl; + kunit_debugfs_init(); #ifdef CONFIG_MODULES return register_module_notifier(&kunit_mod_nb); -- 2.39.0.314.g84b9a713c41-goog
