[PATCHv3,07/10] lib: add crc64 tests

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 14b89aa37c5c..149de11ae903 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2214,6 +2214,10 @@  config TEST_UUID
 config TEST_XARRAY
 	tristate "Test the XArray code at runtime"
 
+config TEST_CRC64
+	depends on CRC64
+	tristate "Test the crc64 code at runtime"
+
 config TEST_OVERFLOW
 	tristate "Test check_*_overflow() functions at runtime"
 
diff --git a/lib/Makefile b/lib/Makefile
index 130bed83cdf2..0895a3fc3f5a 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -103,6 +103,7 @@  obj-$(CONFIG_TEST_HMM) += test_hmm.o
 obj-$(CONFIG_TEST_FREE_PAGES) += test_free_pages.o
 obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
 obj-$(CONFIG_TEST_REF_TRACKER) += test_ref_tracker.o
+obj-$(CONFIG_TEST_CRC64) += test_crc64.o
 #
 # CFLAGS for compiling floating point code inside the kernel. x86/Makefile turns
 # off the generation of FPU/SSE* instructions for kernel proper but FPU_FLAGS
diff --git a/lib/test_crc64.c b/lib/test_crc64.c
new file mode 100644
index 000000000000..281aacd20f0a
--- /dev/null
+++ b/lib/test_crc64.c
@@ -0,0 +1,133 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Tests were selected from NVM Express NVM Command Set Specification 1.0a,
+ * section 5.2.1.3.5 "64b CRC Test Cases" available here:
+ *
+ *   https://nvmexpress.org/wp-content/uploads/NVMe-NVM-Command-Set-Specification-1.0a-2021.07.26-Ratified.pdf
+ *
+ * Copyright 2022 Keith Busch <kbusch@kernel.org>
+ */
+
+#include <linux/crc64.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/random.h>
+
+static unsigned int tests_passed;
+static unsigned int tests_run;
+
+#define ALL_ZEROS 0x6482D367EB22B64EULL
+#define ALL_FFS 0xC0DDBA7302ECA3ACULL
+#define INC 0x3E729F5F6750449CULL
+#define DEC 0x9A2DF64B8E9E517EULL
+
+static u8 buffer[4096];
+
+#define CRC_CHECK(c, v) do {					\
+	tests_run++;						\
+	if (c != v)						\
+		printk("BUG at %s:%d expected:%llx got:%llx\n", \
+			__func__, __LINE__, v, c);		\
+	else							\
+		tests_passed++;					\
+} while (0)
+
+static void randomize(u64 *b, int size)
+{
+	int i;
+
+	for (i = 0; i < size / 8; i++)
+		b[i] = get_random_u64();
+}
+
+static void crc_speed_tests(void)
+{
+	unsigned long size = 1 << 20;
+	unsigned test_size;
+	void *b;
+
+	b = vmalloc(size);
+	if (!b)
+		return;
+
+	test_size = 512;
+	while (test_size <= size) {
+		ktime_t start_time, end_time;
+		u64 crc1, crc2;
+		s64 t1, t2;
+		int i;
+
+		randomize(b, test_size);
+		crc1 = crc2 = ~0ULL;
+
+		start_time = ktime_get();
+		for (i = 0; i < 1024; i++)
+			crc1 = crc64_rocksoft_generic(crc1, b, test_size);
+		end_time = ktime_get();
+		t1 = ktime_us_delta(end_time, start_time);
+
+		start_time = ktime_get();
+		for (i = 0; i < 1024; i++)
+			crc2 = crc64_rocksoft_update(crc2, b, test_size);
+		end_time = ktime_get();
+		t2 = ktime_us_delta(end_time, start_time);
+
+		printk("Size:%-7u Generic:%-7lld Library:%lld\n", test_size,
+			t1, t2);
+		CRC_CHECK(crc1, crc2);
+
+		test_size <<= 1;
+	}
+
+        vfree(b);
+}
+
+static int crc_tests(void)
+{
+	__u64 crc;
+	int i;
+
+	memset(buffer, 0, sizeof(buffer));
+	crc = crc64_rocksoft_generic(~0ULL, buffer, 4096);
+	CRC_CHECK(crc, ALL_ZEROS);
+
+	crc = crc64_rocksoft(buffer, 4096);
+	CRC_CHECK(crc, ALL_ZEROS);
+
+	memset(buffer, 0xff, sizeof(buffer));
+	crc = crc64_rocksoft_generic(~0ULL, buffer, 4096);
+	CRC_CHECK(crc, ALL_FFS);
+
+	crc = crc64_rocksoft(buffer, 4096);
+	CRC_CHECK(crc, ALL_FFS);
+
+	for (i = 0; i < 4096; i++)
+		buffer[i] = i & 0xff;
+	crc = crc64_rocksoft_generic(~0ULL, buffer, 4096);
+	CRC_CHECK(crc, INC);
+
+	crc = crc64_rocksoft(buffer, 4096);
+	CRC_CHECK(crc, INC);
+
+	for (i = 0; i < 4096; i++)
+		buffer[i] = 0xff - (i & 0xff);
+	crc = crc64_rocksoft_generic(~0ULL, buffer, 4096);
+	CRC_CHECK(crc, DEC);
+
+	crc = crc64_rocksoft(buffer, 4096);
+	CRC_CHECK(crc, DEC);
+
+	crc_speed_tests();
+
+	printk("CRC64: %u of %u tests passed\n", tests_passed, tests_run);
+	return (tests_run == tests_passed) ? 0 : -EINVAL;
+}
+
+static void crc_exit(void)
+{
+}
+
+module_init(crc_tests);
+module_exit(crc_exit);
+MODULE_AUTHOR("Keith Busch <kbusch@kernel.org>");
+MODULE_LICENSE("GPL");