lib/crc_kunit.c: add KUnit test suite for CRC library functions

Add a KUnit test suite for the crc16, crc_t10dif, crc32_le, crc32_be,
crc32c, and crc64_be library functions.  It avoids code duplication by
sharing most logic among all CRC variants.  The test suite includes:

- Differential fuzz test of each CRC function against a simple
  bit-at-a-time reference implementation.
- Test for CRC combination, when implemented by a CRC variant.
- Optional benchmark of each CRC function with various data lengths.

This is intended as a replacement for crc32test and crc16_kunit, as well
as a new test for CRC variants which didn't previously have a test.

Reviewed-by: Ard Biesheuvel <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Cc: Vinicius Peixoto <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Eric Biggers <[email protected]>

lib/Kconfig.debug

@@ -2838,6 +2838,26 @@ config HW_BREAKPOINT_KUNIT_TEST
 
 	  If unsure, say N.
 
+config CRC_KUNIT_TEST
+	tristate "KUnit tests for CRC functions" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	select CRC16
+	select CRC_T10DIF
+	select CRC32
+	select CRC64
+	help
+	  Unit tests for the CRC library functions.
+
+	  This is intended to help people writing architecture-specific
+	  optimized versions.  If unsure, say N.
+
+config CRC_BENCHMARK
+	bool "Benchmark for the CRC functions"
+	depends on CRC_KUNIT_TEST
+	help
+	  Include benchmarks in the KUnit test suite for the CRC functions.
+
 config SIPHASH_KUNIT_TEST
 	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
 	depends on KUNIT

lib/Makefile

@@ -391,6 +391,7 @@ CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-overread)
 CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-truncation)
 CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN)
 obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
+obj-$(CONFIG_CRC_KUNIT_TEST) += crc_kunit.o
 obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o
 obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o
 obj-$(CONFIG_CRC16_KUNIT_TEST) += crc16_kunit.o