[RFC PATCH 6/9] crypto: crc-t10dif/arm - move PMULL based code into core library

[Ard Biesheuvel]

Move the PMULL based routines out of the crypto API into the core
CRC-T10DIF library.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
 arch/arm/crypto/crct10dif-ce-glue.c | 78 ++++++--------------
 1 file changed, 22 insertions(+), 56 deletions(-)

diff --git a/arch/arm/crypto/crct10dif-ce-glue.c b/arch/arm/crypto/crct10dif-ce-glue.c
index d428355cf38d..2020d9c29ff1 100644
--- a/arch/arm/crypto/crct10dif-ce-glue.c
+++ b/arch/arm/crypto/crct10dif-ce-glue.c
@@ -10,12 +10,11 @@
 
 #include <linux/crc-t10dif.h>
 #include <linux/init.h>
+#include <linux/ffp.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/string.h>
 
-#include <crypto/internal/hash.h>
-
 #include <asm/neon.h>
 #include <asm/simd.h>
 
@@ -23,74 +22,42 @@
 
 asmlinkage u16 crc_t10dif_pmull(u16 init_crc, const u8 buf[], u32 len);
 
-static int crct10dif_init(struct shash_desc *desc)
+static __u16 crct10dif_update_arm(__u16 crc, const u8 *data, unsigned int length)
 {
-	u16 *crc = shash_desc_ctx(desc);
-
-	*crc = 0;
-	return 0;
-}
-
-static int crct10dif_update(struct shash_desc *desc, const u8 *data,
-			    unsigned int length)
-{
-	u16 *crc = shash_desc_ctx(desc);
 	unsigned int l;
 
-	if (!may_use_simd()) {
-		*crc = crc_t10dif_generic(*crc, data, length);
-	} else {
-		if (unlikely((u32)data % CRC_T10DIF_PMULL_CHUNK_SIZE)) {
-			l = min_t(u32, length, CRC_T10DIF_PMULL_CHUNK_SIZE -
-				  ((u32)data % CRC_T10DIF_PMULL_CHUNK_SIZE));
+	if (!may_use_simd())
+		return crc_t10dif_generic(crc, data, length);
 
-			*crc = crc_t10dif_generic(*crc, data, l);
+	if (unlikely((u32)data % CRC_T10DIF_PMULL_CHUNK_SIZE)) {
+		l = min_t(u32, length, CRC_T10DIF_PMULL_CHUNK_SIZE -
+			  ((u32)data % CRC_T10DIF_PMULL_CHUNK_SIZE));
 
-			length -= l;
-			data += l;
-		}
-		if (length > 0) {
-			kernel_neon_begin();
-			*crc = crc_t10dif_pmull(*crc, data, length);
-			kernel_neon_end();
-		}
-	}
-	return 0;
-}
+		crc = crc_t10dif_generic(crc, data, l);
 
-static int crct10dif_final(struct shash_desc *desc, u8 *out)
-{
-	u16 *crc = shash_desc_ctx(desc);
-
-	*(u16 *)out = *crc;
-	return 0;
+		length -= l;
+		data += l;
+	}
+	if (length > 0) {
+		kernel_neon_begin();
+		crc = crc_t10dif_pmull(crc, data, length);
+		kernel_neon_end();
+	}
+	return crc;
 }
 
-static struct shash_alg crc_t10dif_alg = {
-	.digestsize		= CRC_T10DIF_DIGEST_SIZE,
-	.init			= crct10dif_init,
-	.update			= crct10dif_update,
-	.final			= crct10dif_final,
-	.descsize		= CRC_T10DIF_DIGEST_SIZE,
-
-	.base.cra_name		= "crct10dif",
-	.base.cra_driver_name	= "crct10dif-arm-ce",
-	.base.cra_priority	= 200,
-	.base.cra_blocksize	= CRC_T10DIF_BLOCK_SIZE,
-	.base.cra_module	= THIS_MODULE,
-};
-
 static int __init crc_t10dif_mod_init(void)
 {
-	if (!(elf_hwcap2 & HWCAP2_PMULL))
-		return -ENODEV;
+	SET_FFP(crc_t10dif_update_arch, crct10dif_update_arm);
 
-	return crypto_register_shash(&crc_t10dif_alg);
+	return 0;
 }
 
 static void __exit crc_t10dif_mod_exit(void)
 {
-	crypto_unregister_shash(&crc_t10dif_alg);
+	RESET_FFP(crc_t10dif_update_arch);
+	/* wait for all users to switch back to the old version */
+	synchronize_rcu();
 }
 
 module_init(crc_t10dif_mod_init);
@@ -98,4 +65,3 @@ module_exit(crc_t10dif_mod_exit);
 
 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>");
 MODULE_LICENSE("GPL v2");
-MODULE_ALIAS_CRYPTO("crct10dif");
-- 
2.11.0