On Mon, Dec 14, 2020 at 11:59:52AM +0800, Tony W Wang-oc wrote: Didn't I mention something about a comment? > static const struct x86_cpu_id crc32c_cpu_id[] = { > + X86_MATCH_VENDOR_FAM_FEATURE(ZHAOXIN, 0x6, X86_FEATURE_XMM4_2, 1), > + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(ZHAOXIN, 0x7, 0x1b, X86_FEATURE_XMM4_2, 1), > + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(ZHAOXIN, 0x7, 0x3b, X86_FEATURE_XMM4_2, 1), > + X86_MATCH_VENDOR_FAM_FEATURE(CENTAUR, 0x6, X86_FEATURE_XMM4_2, 1), > + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(CENTAUR, 0x7, 0x1b, X86_FEATURE_XMM4_2, 1), > + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(CENTAUR, 0x7, 0x3b, X86_FEATURE_XMM4_2, 1), > X86_MATCH_FEATURE(X86_FEATURE_XMM4_2, NULL), > {} Also, the above is weird in that is has the negative entries marked positive, and 1/NULL are inconsistent. Something like so then? --- diff --git a/arch/x86/crypto/crc32c-intel_glue.c b/arch/x86/crypto/crc32c-intel_glue.c index feccb5254c7e..f6e6669a5102 100644 --- a/arch/x86/crypto/crc32c-intel_glue.c +++ b/arch/x86/crypto/crc32c-intel_glue.c @@ -215,14 +215,31 @@ static struct shash_alg alg = { }; static const struct x86_cpu_id crc32c_cpu_id[] = { - X86_MATCH_FEATURE(X86_FEATURE_XMM4_2, NULL), + /* + * Negative entries; exclude these chips from using this driver. + * They match the positive rule below, but their CRC32 instruction + * implementation is so slow, it doesn't merrit use. + */ + X86_MATCH_VENDOR_FAM_FEATURE(ZHAOXIN, 0x6, X86_FEATURE_XMM4_2, false), + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(ZHAOXIN, 0x7, 0x1b, X86_FEATURE_XMM4_2, false), + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(ZHAOXIN, 0x7, 0x3b, X86_FEATURE_XMM4_2, false), + X86_MATCH_VENDOR_FAM_FEATURE(CENTAUR, 0x6, X86_FEATURE_XMM4_2, false), + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(CENTAUR, 0x7, 0x1b, X86_FEATURE_XMM4_2, false), + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(CENTAUR, 0x7, 0x3b, X86_FEATURE_XMM4_2, false), + /* + * Positive entry; SSE-4.2 instructions include special purpose CRC32 + * instructions. + */ + X86_MATCH_FEATURE(X86_FEATURE_XMM4_2, true), {} }; MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id); static int __init crc32c_intel_mod_init(void) { - if (!x86_match_cpu(crc32c_cpu_id)) + const struct x86_cpu_id *m = x86_match_cpu(crc32c_cpu_id); + + if (!m || !m->driver_data) return -ENODEV; #ifdef CONFIG_X86_64 if (boot_cpu_has(X86_FEATURE_PCLMULQDQ)) {