From patchwork Thu Dec 21 10:38:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Richard Fitzgerald X-Patchwork-Id: 758340 Received: from mx0b-001ae601.pphosted.com (mx0b-001ae601.pphosted.com [67.231.152.168]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E0E486A35A; Thu, 21 Dec 2023 10:39:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=opensource.cirrus.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=opensource.cirrus.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cirrus.com header.i=@cirrus.com header.b="Wbuvniu8" Received: from pps.filterd (m0077474.ppops.net [127.0.0.1]) by mx0b-001ae601.pphosted.com (8.17.1.24/8.17.1.24) with ESMTP id 3BL5AA93026850; Thu, 21 Dec 2023 04:39:02 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cirrus.com; h= from:to:cc:subject:date:message-id:mime-version:content-type :content-transfer-encoding; s=PODMain02222019; bh=8swxHzLIkGDzxO I8Vz/Y9c2HnswUaOPTF6vff2JboJ8=; b=Wbuvniu8ayMnN13D8UbM+PrBpqBKl0 EJ7oxwH1b2NXi42Q9t44nQD72ACQ7e0dWv64s3xBf118yFvdNQ3bSgivqpJ21HSv 1vmtSpFg1V7h0R72WTYK4udLVqfAnM3MuiG28yF6VKc74aiYbMs6P0vti1TT/91q eZOGSSS1zyj/E0FxIfwMFm7HyG27gez2dBSUhAe5oI+Iv/K7fH4zgcZk26cUU/Q2 NjbBGB/hmN7CF/qiGV90vLcrowjnvqjeIQtN+HjXlFdf7TOUj60pePmxuP32/H4G Lx9b/Mbh+6CIuRCWrI2vZVuQqWgTHQuu1DD3U5DpAMA6Prz49D8P/j7w== Received: from ediex02.ad.cirrus.com ([84.19.233.68]) by mx0b-001ae601.pphosted.com (PPS) with ESMTPS id 3v196nf3tk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 21 Dec 2023 04:39:01 -0600 (CST) Received: from ediex01.ad.cirrus.com (198.61.84.80) by ediex02.ad.cirrus.com (198.61.84.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Thu, 21 Dec 2023 10:39:00 +0000 Received: from ediswmail.ad.cirrus.com (198.61.86.93) by ediex01.ad.cirrus.com (198.61.84.80) with Microsoft SMTP Server id 15.2.1118.40 via Frontend Transport; Thu, 21 Dec 2023 10:39:00 +0000 Received: from work-debian.ad.cirrus.com (unknown [198.61.64.187]) by ediswmail.ad.cirrus.com (Postfix) with ESMTP id C722711D1; Thu, 21 Dec 2023 10:38:59 +0000 (UTC) From: Richard Fitzgerald To: , , CC: , , , , "Richard Fitzgerald" Subject: [PATCH v2 1/2] kunit: Allow passing function pointer to kunit_activate_static_stub() Date: Thu, 21 Dec 2023 10:38:56 +0000 Message-ID: <20231221103858.46010-1-rf@opensource.cirrus.com> X-Mailer: git-send-email 2.30.2 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-ORIG-GUID: iyZnRFjCVFG0a-1xJ0ABpQ3lQ2HcCyVa X-Proofpoint-GUID: iyZnRFjCVFG0a-1xJ0ABpQ3lQ2HcCyVa X-Proofpoint-Spam-Reason: safe Swap the arguments to typecheck_fn() in kunit_activate_static_stub() so that real_fn_addr can be either the function itself or a pointer to that function. This is useful to simplify redirecting static functions in a module. Having to pass the actual function meant that it must be exported from the module. Either making the 'static' and EXPORT_SYMBOL*() conditional (which makes the code messy), or change it to always exported (which increases the export namespace and prevents the compiler inlining a trivial stub function in non-test builds). With the original definition of kunit_activate_static_stub() the address of real_fn_addr was passed to typecheck_fn() as the type to be passed. This meant that if real_fn_addr was a pointer-to-function it would resolve to a ** instead of a *, giving an error like this: error: initialization of ‘int (**)(int)’ from incompatible pointer type ‘int (*)(int)’ [-Werror=incompatible-pointer-types] kunit_activate_static_stub(test, add_one_fn_ptr, subtract_one); | ^~~~~~~~~~~~ ./include/linux/typecheck.h:21:25: note: in definition of macro ‘typecheck_fn’ 21 | ({ typeof(type) __tmp = function; \ Swapping the arguments to typecheck_fn makes it take the type of a pointer to the replacement function. Either a function or a pointer to function can be assigned to that. For example: static int some_function(int x) { /* whatever */ } int (* some_function_ptr)(int) = some_function; static int replacement(int x) { /* whatever */ } Then: kunit_activate_static_stub(test, some_function, replacement); yields: typecheck_fn(typeof(&replacement), some_function); and: kunit_activate_static_stub(test, some_function_ptr, replacement); yields: typecheck_fn(typeof(&replacement), some_function_ptr); The two typecheck_fn() then resolve to: int (*__tmp)(int) = some_function; and int (*__tmp)(int) = some_function_ptr; Both of these are valid. In the first case the compiler inserts an implicit '&' to take the address of the supplied function, and in the second case the RHS is already a pointer to the same type. Signed-off-by: Richard Fitzgerald Reviewed-by: Rae Moar --- No changes since V1. --- include/kunit/static_stub.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/kunit/static_stub.h b/include/kunit/static_stub.h index 85315c80b303..bf940322dfc0 100644 --- a/include/kunit/static_stub.h +++ b/include/kunit/static_stub.h @@ -93,7 +93,7 @@ void __kunit_activate_static_stub(struct kunit *test, * The redirection can be disabled again with kunit_deactivate_static_stub(). */ #define kunit_activate_static_stub(test, real_fn_addr, replacement_addr) do { \ - typecheck_fn(typeof(&real_fn_addr), replacement_addr); \ + typecheck_fn(typeof(&replacement_addr), real_fn_addr); \ __kunit_activate_static_stub(test, real_fn_addr, replacement_addr); \ } while (0) From patchwork Thu Dec 21 10:38:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Fitzgerald X-Patchwork-Id: 757312 Received: from mx0b-001ae601.pphosted.com (mx0a-001ae601.pphosted.com [67.231.149.25]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E75C36A018; Thu, 21 Dec 2023 10:39:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=opensource.cirrus.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=opensource.cirrus.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cirrus.com header.i=@cirrus.com header.b="PijBGgiT" Received: from pps.filterd (m0077473.ppops.net [127.0.0.1]) by mx0a-001ae601.pphosted.com (8.17.1.24/8.17.1.24) with ESMTP id 3BL6AEek014182; Thu, 21 Dec 2023 04:39:03 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cirrus.com; h= from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding:content-type; s= PODMain02222019; bh=rNoek7i2hFRCbF498o2jHOYXWryLj1e8+AacX3XSeLs=; b= PijBGgiTMMk/lKX+rDChXaawdFoWoo/wCCtCY6Q/h9oR7gOQrvrtJhraKZlB9scW hXpzsTUuAFTo5OHnFkqh3kjWwDKjkc7Ng4eomcFkOUmxL3EShbArXvJqMNmuX4uJ g17acFQgTFYBGfqdxCwVbLCyGsBnielHLpTHoGGqgrUe8Aw+mZqgs69nPRJSRVLO Omq+4c/F0BTkkyBOWWAri0vWAqCn39bpGN9mTh+zDklzzSHiiUr85nAB1SSla8cx h5uOcbufgZjkrd8z5sGrzRotFd+kdhRXy48GdyYr7Ou5Y9YsYP4nYL1CClxPioOg L4qj0Svz6tLLWaPzmaJc3w== Received: from ediex01.ad.cirrus.com ([84.19.233.68]) by mx0a-001ae601.pphosted.com (PPS) with ESMTPS id 3v1a627625-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 21 Dec 2023 04:39:02 -0600 (CST) Received: from ediex02.ad.cirrus.com (198.61.84.81) by ediex01.ad.cirrus.com (198.61.84.80) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Thu, 21 Dec 2023 10:39:00 +0000 Received: from ediswmail.ad.cirrus.com (198.61.86.93) by anon-ediex02.ad.cirrus.com (198.61.84.81) with Microsoft SMTP Server id 15.2.1118.40 via Frontend Transport; Thu, 21 Dec 2023 10:39:00 +0000 Received: from work-debian.ad.cirrus.com (unknown [198.61.64.187]) by ediswmail.ad.cirrus.com (Postfix) with ESMTP id 3EC9311CC; Thu, 21 Dec 2023 10:39:00 +0000 (UTC) From: Richard Fitzgerald To: , , CC: , , , , "Richard Fitzgerald" Subject: [PATCH v2 2/2] kunit: Add example of kunit_activate_static_stub() with pointer-to-function Date: Thu, 21 Dec 2023 10:38:57 +0000 Message-ID: <20231221103858.46010-2-rf@opensource.cirrus.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20231221103858.46010-1-rf@opensource.cirrus.com> References: <20231221103858.46010-1-rf@opensource.cirrus.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-GUID: 90crQN90oj-4uhzrdwETgjBfHpjxCXbE X-Proofpoint-ORIG-GUID: 90crQN90oj-4uhzrdwETgjBfHpjxCXbE X-Proofpoint-Spam-Reason: safe Adds a variant of example_static_stub_test() that shows use of a pointer-to-function with kunit_activate_static_stub(). A const pointer to the add_one() function is declared. This pointer-to-function is passed to kunit_activate_static_stub() and kunit_deactivate_static_stub() instead of passing add_one directly. Signed-off-by: Richard Fitzgerald Reviewed-by: David Gow --- V2: Added comment for add_one_fn_ptr. --- lib/kunit/kunit-example-test.c | 35 ++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c index 359dbee10201..798924f7cc86 100644 --- a/lib/kunit/kunit-example-test.c +++ b/lib/kunit/kunit-example-test.c @@ -168,6 +168,16 @@ static int subtract_one(int i) return i - 1; } +/* + * If the function to be replaced is static within a module it is + * useful to export a pointer to that function instead of having + * to change the static function to a non-static exported function. + * + * This pointer simulates a module exporting a pointer to a static + * function. + */ +static int (* const add_one_fn_ptr)(int i) = add_one; + /* * This test shows the use of static stubs. */ @@ -187,6 +197,30 @@ static void example_static_stub_test(struct kunit *test) KUNIT_EXPECT_EQ(test, add_one(1), 2); } +/* + * This test shows the use of static stubs when the function being + * replaced is provided as a pointer-to-function instead of the + * actual function. This is useful for providing access to static + * functions in a module by exporting a pointer to that function + * instead of having to change the static function to a non-static + * exported function. + */ +static void example_static_stub_using_fn_ptr_test(struct kunit *test) +{ + /* By default, function is not stubbed. */ + KUNIT_EXPECT_EQ(test, add_one(1), 2); + + /* Replace add_one() with subtract_one(). */ + kunit_activate_static_stub(test, add_one_fn_ptr, subtract_one); + + /* add_one() is now replaced. */ + KUNIT_EXPECT_EQ(test, add_one(1), 0); + + /* Return add_one() to normal. */ + kunit_deactivate_static_stub(test, add_one_fn_ptr); + KUNIT_EXPECT_EQ(test, add_one(1), 2); +} + static const struct example_param { int value; } example_params_array[] = { @@ -259,6 +293,7 @@ static struct kunit_case example_test_cases[] = { KUNIT_CASE(example_mark_skipped_test), KUNIT_CASE(example_all_expect_macros_test), KUNIT_CASE(example_static_stub_test), + KUNIT_CASE(example_static_stub_using_fn_ptr_test), KUNIT_CASE(example_priv_test), KUNIT_CASE_PARAM(example_params_test, example_gen_params), KUNIT_CASE_SLOW(example_slow_test),