linux-kernel - Re: [PATCH V3 2/2] lib/test_bits.c: Add tests for GENMASK

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Message-ID: <e452648d-fbbd-475d-b8e5-a199f56dfd98@arm.com>
Date: Tue, 20 Aug 2024 09:06:10 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: linux-kernel@...r.kernel.org
Cc: ardb@...nel.org, Andrew Morton <akpm@...ux-foundation.org>,
 Yury Norov <yury.norov@...il.com>,
 Rasmus Villemoes <linux@...musvillemoes.dk>, Arnd Bergmann <arnd@...db.de>,
 linux-arch@...r.kernel.org
Subject: Re: [PATCH V3 2/2] lib/test_bits.c: Add tests for GENMASK_U128()



On 8/1/24 12:46, Anshuman Khandual wrote:
> This adds GENMASK_U128() tests although currently only 64 bit wide masks
> are being tested.
> 
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: linux-kernel@...r.kernel.org
> Reviewed-by: Arnd Bergmann <arnd@...db.de>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
> ---
>  lib/test_bits.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/lib/test_bits.c b/lib/test_bits.c
> index 01313980f175..d3d858b24e02 100644
> --- a/lib/test_bits.c
> +++ b/lib/test_bits.c
> @@ -39,6 +39,26 @@ static void genmask_ull_test(struct kunit *test)
>  #endif
>  }
>  
> +static void genmask_u128_test(struct kunit *test)
> +{
> +#ifdef CONFIG_ARCH_SUPPORTS_INT128
> +	/* Tests mask generation only when the mask width is within 64 bits */
> +	KUNIT_EXPECT_EQ(test, 0x0000000000ff0000ULL, GENMASK_U128(87, 80) >> 64);
> +	KUNIT_EXPECT_EQ(test, 0x0000000000ffffffULL, GENMASK_U128(87, 64) >> 64);
> +	KUNIT_EXPECT_EQ(test, 0x0000000000000001ULL, GENMASK_U128(0, 0));
> +	KUNIT_EXPECT_EQ(test, 0xffffffffffffffffULL, GENMASK_U128(63, 0));
> +	KUNIT_EXPECT_EQ(test, 0xffffffffffffffffULL, GENMASK_U128(64, 0) >> 1);
> +	KUNIT_EXPECT_EQ(test, 0x00000000ffffffffULL, GENMASK_U128(81, 50) >> 50);
> +
> +#ifdef TEST_GENMASK_FAILURES
> +	/* these should fail compilation */
> +	GENMASK_U128(0, 1);
> +	GENMASK_U128(0, 10);
> +	GENMASK_U128(9, 10);
> +#endif /* TEST_GENMASK_FAILURES */
> +#endif /* CONFIG_ARCH_SUPPORTS_INT128 */
> +}
> +
>  static void genmask_input_check_test(struct kunit *test)
>  {
>  	unsigned int x, y;
> @@ -56,12 +76,15 @@ static void genmask_input_check_test(struct kunit *test)
>  	/* Valid input */
>  	KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(1, 1));
>  	KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(39, 21));
> +	KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(100, 80));
> +	KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(110, 65));
>  }
>  
>  
>  static struct kunit_case bits_test_cases[] = {
>  	KUNIT_CASE(genmask_test),
>  	KUNIT_CASE(genmask_ull_test),
> +	KUNIT_CASE(genmask_u128_test),
>  	KUNIT_CASE(genmask_input_check_test),
>  	{}
>  };

Here is the updated test case to cover some more corner cases. Please
do let me know if something more can be added here to the list.

--- a/lib/test_bits.c
+++ b/lib/test_bits.c
@@ -39,6 +39,36 @@ static void genmask_ull_test(struct kunit *test)
 #endif
 }
 
+static void genmask_u128_test(struct kunit *test)
+{
+#ifdef CONFIG_ARCH_SUPPORTS_INT128
+       /* Below 64 bit masks */
+       KUNIT_EXPECT_EQ(test, 0x0000000000000001ull, GENMASK_U128(0, 0));
+       KUNIT_EXPECT_EQ(test, 0x0000000000000003ull, GENMASK_U128(1, 0));
+       KUNIT_EXPECT_EQ(test, 0x0000000000000006ull, GENMASK_U128(2, 1));
+       KUNIT_EXPECT_EQ(test, 0x00000000ffffffffull, GENMASK_U128(31, 0));
+       KUNIT_EXPECT_EQ(test, 0x000000ffffe00000ull, GENMASK_U128(39, 21));
+       KUNIT_EXPECT_EQ(test, 0xffffffffffffffffull, GENMASK_U128(63, 0));
+
+       /* Above 64 bit masks - only 64 bit portion can be validated once */
+       KUNIT_EXPECT_EQ(test, 0xffffffffffffffffull, GENMASK_U128(64, 0) >> 1);
+       KUNIT_EXPECT_EQ(test, 0x00000000ffffffffull, GENMASK_U128(81, 50) >> 50);
+       KUNIT_EXPECT_EQ(test, 0x0000000000ffffffull, GENMASK_U128(87, 64) >> 64);
+       KUNIT_EXPECT_EQ(test, 0x0000000000ff0000ull, GENMASK_U128(87, 80) >> 64);
+
+       KUNIT_EXPECT_EQ(test, 0xffffffffffffffffull, GENMASK_U128(127, 0) >> 64);
+       KUNIT_EXPECT_EQ(test, 0xffffffffffffffffull, (u64)GENMASK_U128(127, 0));
+       KUNIT_EXPECT_EQ(test, 0x0000000000000003ull, GENMASK_U128(127, 126) >> 126);
+       KUNIT_EXPECT_EQ(test, 0x0000000000000001ull, GENMASK_U128(127, 127) >> 127);
+#ifdef TEST_GENMASK_FAILURES
+       /* these should fail compilation */
+       GENMASK_U128(0, 1);
+       GENMASK_U128(0, 10);
+       GENMASK_U128(9, 10);
+#endif /* TEST_GENMASK_FAILURES */
+#endif /* CONFIG_ARCH_SUPPORTS_INT128 */
+}
+
 static void genmask_input_check_test(struct kunit *test)
 {
        unsigned int x, y;
@@ -56,12 +86,16 @@ static void genmask_input_check_test(struct kunit *test)
        /* Valid input */
        KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(1, 1));
        KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(39, 21));
+       KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(100, 80));
+       KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(110, 65));
+       KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(127, 0));
 }
 
 
 static struct kunit_case bits_test_cases[] = {
        KUNIT_CASE(genmask_test),
        KUNIT_CASE(genmask_ull_test),
+       KUNIT_CASE(genmask_u128_test),
        KUNIT_CASE(genmask_input_check_test),
        {}
 };
(END)