[PATCHv3 06/10] crypto: add rocksoft 64b crc framework

[Keith Busch]

Hardware specific features may be able to calculate a crc64, so provide
a framework for drivers to register their implementation. If nothing is
registered, fallback to the generic table lookup implementation. The
implementation is modeled after the crct10dif equivalent.

Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
---
 crypto/Kconfig                  |   9 +++
 crypto/Makefile                 |   1 +
 crypto/crc64_rocksoft_generic.c | 104 +++++++++++++++++++++++++
 include/linux/crc64.h           |   5 ++
 lib/Kconfig                     |   9 +++
 lib/Makefile                    |   1 +
 lib/crc64-rocksoft.c            | 129 ++++++++++++++++++++++++++++++++
 7 files changed, 258 insertions(+)
 create mode 100644 crypto/crc64_rocksoft_generic.c
 create mode 100644 lib/crc64-rocksoft.c

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 442765219c37..e343147b9f8f 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -735,6 +735,15 @@ config CRYPTO_CRCT10DIF_VPMSUM
 	  multiply-sum (vpmsum) instructions, introduced in POWER8. Enable on
 	  POWER8 and newer processors for improved performance.
 
+config CRYPTO_CRC64_ROCKSOFT
+	tristate "Rocksoft Model CRC64 algorithm"
+	depends on CRC64
+	select CRYPTO_HASH
+	help
+	  Rocksoft Model CRC64 computation is being cast as a crypto
+	  transform. This allows for faster crc64 transforms to be used
+	  if they are available.
+
 config CRYPTO_VPMSUM_TESTER
 	tristate "Powerpc64 vpmsum hardware acceleration tester"
 	depends on CRYPTO_CRCT10DIF_VPMSUM && CRYPTO_CRC32C_VPMSUM
diff --git a/crypto/Makefile b/crypto/Makefile
index d76bff8d0ffd..f754c4d17d6b 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -152,6 +152,7 @@ obj-$(CONFIG_CRYPTO_MICHAEL_MIC) += michael_mic.o
 obj-$(CONFIG_CRYPTO_CRC32C) += crc32c_generic.o
 obj-$(CONFIG_CRYPTO_CRC32) += crc32_generic.o
 obj-$(CONFIG_CRYPTO_CRCT10DIF) += crct10dif_common.o crct10dif_generic.o
+obj-$(CONFIG_CRYPTO_CRC64_ROCKSOFT) += crc64_rocksoft_generic.o
 obj-$(CONFIG_CRYPTO_AUTHENC) += authenc.o authencesn.o
 obj-$(CONFIG_CRYPTO_LZO) += lzo.o lzo-rle.o
 obj-$(CONFIG_CRYPTO_LZ4) += lz4.o
diff --git a/crypto/crc64_rocksoft_generic.c b/crypto/crc64_rocksoft_generic.c
new file mode 100644
index 000000000000..55bad1939614
--- /dev/null
+++ b/crypto/crc64_rocksoft_generic.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Cryptographic API.
+ *
+ * Rocksoft^TM model CRC64 Crypto Transform
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/crc64.h>
+#include <crypto/internal/hash.h>
+#include <crypto/internal/simd.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <asm/cpufeatures.h>
+#include <asm/cpu_device_id.h>
+#include <asm/simd.h>
+
+struct chksum_desc_ctx {
+	u64 crc;
+};
+
+static int chksum_init(struct shash_desc *desc)
+{
+	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+	ctx->crc = 0;
+
+	return 0;
+}
+
+static int chksum_update(struct shash_desc *desc, const u8 *data,
+			 unsigned int length)
+{
+	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+	ctx->crc = crc64_rocksoft_generic(ctx->crc, data, length);
+	return 0;
+}
+
+static int chksum_final(struct shash_desc *desc, u8 *out)
+{
+	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+	*(u64 *)out = ctx->crc;
+	return 0;
+}
+
+static int __chksum_finup(u64 crc, const u8 *data, unsigned int len, u8 *out)
+{
+	*(u64 *)out = crc64_rocksoft_generic(crc, data, len);
+	return 0;
+}
+
+static int chksum_finup(struct shash_desc *desc, const u8 *data,
+			unsigned int len, u8 *out)
+{
+	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+	return __chksum_finup(ctx->crc, data, len, out);
+}
+
+static int chksum_digest(struct shash_desc *desc, const u8 *data,
+			 unsigned int length, u8 *out)
+{
+	return __chksum_finup(0, data, length, out);
+}
+
+static struct shash_alg alg = {
+	.digestsize	= 	8,
+	.init		=	chksum_init,
+	.update		=	chksum_update,
+	.final		=	chksum_final,
+	.finup		=	chksum_finup,
+	.digest		=	chksum_digest,
+	.descsize	=	sizeof(struct chksum_desc_ctx),
+	.base		=	{
+		.cra_name		=	CRC64_ROCKSOFT_STRING,
+		.cra_driver_name	=	"crc64-rocksoft-generic",
+		.cra_priority		=	200,
+		.cra_blocksize		=	1,
+		.cra_module		=	THIS_MODULE,
+	}
+};
+
+static int __init crc64_rocksoft_x86_mod_init(void)
+{
+	return crypto_register_shash(&alg);
+}
+
+static void __exit crc64_rocksoft_x86_mod_fini(void)
+{
+	crypto_unregister_shash(&alg);
+}
+
+module_init(crc64_rocksoft_x86_mod_init);
+module_exit(crc64_rocksoft_x86_mod_fini);
+
+MODULE_AUTHOR("Keith Busch <kbusch@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Rocksoft model CRC64 calculation.");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_CRYPTO("crc64-rocksoft");
+MODULE_ALIAS_CRYPTO("crc64-rocksoft-generic");
diff --git a/include/linux/crc64.h b/include/linux/crc64.h
index 9480f38cc7cf..e044c60d1e61 100644
--- a/include/linux/crc64.h
+++ b/include/linux/crc64.h
@@ -7,7 +7,12 @@
 
 #include <linux/types.h>
 
+#define CRC64_ROCKSOFT_STRING "crc64-rocksoft"
+
 u64 __pure crc64_be(u64 crc, const void *p, size_t len);
 u64 __pure crc64_rocksoft_generic(u64 crc, const void *p, size_t len);
 
+u64 crc64_rocksoft(const unsigned char *buffer, size_t len);
+u64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len);
+
 #endif /* _LINUX_CRC64_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index c80fde816a7e..d4a46d635cb1 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -146,6 +146,15 @@ config CRC_T10DIF
 	  kernel tree needs to calculate CRC checks for use with the
 	  SCSI data integrity subsystem.
 
+config CRC64_ROCKSOFT
+	tristate "CRC calculation for the Rocksoft^TM model CRC64"
+	select CRYPTO
+	select CRYPTO_CRC64_ROCKSOFT
+	help
+	  This option is only needed if a module that's not in the
+	  kernel tree needs to calculate CRC checks for use with the
+	  rocksoft model parameters.
+
 config CRC_ITU_T
 	tristate "CRC ITU-T V.41 functions"
 	help
diff --git a/lib/Makefile b/lib/Makefile
index 300f569c626b..130bed83cdf2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -177,6 +177,7 @@ obj-$(CONFIG_LIBCRC32C)	+= libcrc32c.o
 obj-$(CONFIG_CRC8)	+= crc8.o
 obj-$(CONFIG_XXHASH)	+= xxhash.o
 obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
+obj-$(CONFIG_CRC64_ROCKSOFT) += crc64-rocksoft.o
 
 obj-$(CONFIG_842_COMPRESS) += 842/
 obj-$(CONFIG_842_DECOMPRESS) += 842/
diff --git a/lib/crc64-rocksoft.c b/lib/crc64-rocksoft.c
new file mode 100644
index 000000000000..49d7418ea827
--- /dev/null
+++ b/lib/crc64-rocksoft.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Rocksoft^TM model CRC64 calculation
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/crc64.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <crypto/hash.h>
+#include <crypto/algapi.h>
+#include <linux/static_key.h>
+#include <linux/notifier.h>
+
+static struct crypto_shash __rcu *crc64_rocksoft_tfm;
+static DEFINE_STATIC_KEY_TRUE(crc64_rocksoft_fallback);
+static DEFINE_MUTEX(crc64_rocksoft_mutex);
+static struct work_struct crc64_rocksoft_rehash_work;
+
+static int crc64_rocksoft_notify(struct notifier_block *self, unsigned long val, void *data)
+{
+	struct crypto_alg *alg = data;
+
+	if (val != CRYPTO_MSG_ALG_LOADED ||
+	    strcmp(alg->cra_name, CRC64_ROCKSOFT_STRING))
+		return NOTIFY_DONE;
+
+	schedule_work(&crc64_rocksoft_rehash_work);
+	return NOTIFY_OK;
+}
+
+static void crc64_rocksoft_rehash(struct work_struct *work)
+{
+	struct crypto_shash *new, *old;
+
+	mutex_lock(&crc64_rocksoft_mutex);
+	old = rcu_dereference_protected(crc64_rocksoft_tfm,
+					lockdep_is_held(&crc64_rocksoft_mutex));
+	new = crypto_alloc_shash(CRC64_ROCKSOFT_STRING, 0, 0);
+	if (IS_ERR(new)) {
+		mutex_unlock(&crc64_rocksoft_mutex);
+		return;
+	}
+	rcu_assign_pointer(crc64_rocksoft_tfm, new);
+	mutex_unlock(&crc64_rocksoft_mutex);
+
+	if (old) {
+		synchronize_rcu();
+		crypto_free_shash(old);
+	} else {
+		static_branch_disable(&crc64_rocksoft_fallback);
+	}
+}
+
+static struct notifier_block crc64_rocksoft_nb = {
+	.notifier_call = crc64_rocksoft_notify,
+};
+
+u64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len)
+{
+	struct {
+		struct shash_desc shash;
+		u64 crc;
+	} desc;
+	int err;
+
+	if (static_branch_unlikely(&crc64_rocksoft_fallback))
+		return crc64_rocksoft_generic(crc, buffer, len);
+
+	rcu_read_lock();
+	desc.shash.tfm = rcu_dereference(crc64_rocksoft_tfm);
+	desc.crc = crc;
+	err = crypto_shash_update(&desc.shash, buffer, len);
+	rcu_read_unlock();
+
+	BUG_ON(err);
+
+	return desc.crc;
+}
+EXPORT_SYMBOL(crc64_rocksoft_update);
+
+u64 crc64_rocksoft(const unsigned char *buffer, size_t len)
+{
+	return crc64_rocksoft_update(~0ULL, buffer, len);
+}
+EXPORT_SYMBOL(crc64_rocksoft);
+
+static int __init crc64_rocksoft_mod_init(void)
+{
+	INIT_WORK(&crc64_rocksoft_rehash_work, crc64_rocksoft_rehash);
+	crypto_register_notifier(&crc64_rocksoft_nb);
+	crc64_rocksoft_rehash(&crc64_rocksoft_rehash_work);
+	return 0;
+}
+
+static void __exit crc64_rocksoft_mod_fini(void)
+{
+	crypto_unregister_notifier(&crc64_rocksoft_nb);
+	cancel_work_sync(&crc64_rocksoft_rehash_work);
+	crypto_free_shash(rcu_dereference_protected(crc64_rocksoft_tfm, 1));
+}
+
+module_init(crc64_rocksoft_mod_init);
+module_exit(crc64_rocksoft_mod_fini);
+
+static int crc64_rocksoft_transform_show(char *buffer, const struct kernel_param *kp)
+{
+	struct crypto_shash *tfm;
+	int len;
+
+	if (static_branch_unlikely(&crc64_rocksoft_fallback))
+		return sprintf(buffer, "fallback\n");
+
+	rcu_read_lock();
+	tfm = rcu_dereference(crc64_rocksoft_tfm);
+	len = snprintf(buffer, PAGE_SIZE, "%s\n",
+		       crypto_shash_driver_name(tfm));
+	rcu_read_unlock();
+
+	return len;
+}
+
+module_param_call(transform, NULL, crc64_rocksoft_transform_show, NULL, 0444);
+
+MODULE_AUTHOR("Keith Busch <kbusch@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Rocksoft model CRC64 calculation (library API)");
+MODULE_LICENSE("GPL");
+MODULE_SOFTDEP("pre: crc64");
-- 
2.25.4