lib/crypto: s390/ghash: Migrate optimized code into library

Remove the "ghash-s390" crypto_shash algorithm, and replace it with an
implementation of ghash_blocks_arch() for the GHASH library.

This makes the GHASH library be optimized with CPACF.  It also greatly
reduces the amount of s390-specific glue code that is needed, and it
fixes the issue where this GHASH optimization was disabled by default.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260319061723.1140720-14-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

3 files changed, 0 insertions, 155 deletions

diff --git a/arch/s390/crypto/Kconfig b/arch/s390/crypto/Kconfig
index 79a2d0034258..ee83052dbc15 100644
--- a/arch/s390/crypto/Kconfig
+++ b/arch/s390/crypto/Kconfig
@@ -2,16 +2,6 @@
 
 menu "Accelerated Cryptographic Algorithms for CPU (s390)"
 
-config CRYPTO_GHASH_S390
-	tristate "Hash functions: GHASH"
-	select CRYPTO_HASH
-	help
-	  GCM GHASH hash function (NIST SP800-38D)
-
-	  Architecture: s390
-
-	  It is available as of z196.
-
 config CRYPTO_AES_S390
 	tristate "Ciphers: AES, modes: ECB, CBC, CTR, XTS, GCM"
 	select CRYPTO_SKCIPHER
diff --git a/arch/s390/crypto/Makefile b/arch/s390/crypto/Makefile
index 387a229e1038..4449c1b19ef5 100644
--- a/arch/s390/crypto/Makefile
+++ b/arch/s390/crypto/Makefile
@@ -7,7 +7,6 @@ obj-$(CONFIG_CRYPTO_DES_S390) += des_s390.o
 obj-$(CONFIG_CRYPTO_AES_S390) += aes_s390.o
 obj-$(CONFIG_CRYPTO_PAES_S390) += paes_s390.o
 obj-$(CONFIG_S390_PRNG) += prng.o
-obj-$(CONFIG_CRYPTO_GHASH_S390) += ghash_s390.o
 obj-$(CONFIG_CRYPTO_HMAC_S390) += hmac_s390.o
 obj-$(CONFIG_CRYPTO_PHMAC_S390) += phmac_s390.o
 obj-y += arch_random.o
diff --git a/arch/s390/crypto/ghash_s390.c b/arch/s390/crypto/ghash_s390.c
deleted file mode 100644
index dcbcee37cb63..000000000000
--- a/arch/s390/crypto/ghash_s390.c
+++ /dev/null
@@ -1,144 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Cryptographic API.
- *
- * s390 implementation of the GHASH algorithm for GCM (Galois/Counter Mode).
- *
- * Copyright IBM Corp. 2011
- * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
- */
-
-#include <asm/cpacf.h>
-#include <crypto/ghash.h>
-#include <crypto/internal/hash.h>
-#include <linux/cpufeature.h>
-#include <linux/err.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/string.h>
-
-struct s390_ghash_ctx {
-	u8 key[GHASH_BLOCK_SIZE];
-};
-
-struct s390_ghash_desc_ctx {
-	u8 icv[GHASH_BLOCK_SIZE];
-	u8 key[GHASH_BLOCK_SIZE];
-};
-
-static int ghash_init(struct shash_desc *desc)
-{
-	struct s390_ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
-	struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
-
-	memset(dctx, 0, sizeof(*dctx));
-	memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE);
-
-	return 0;
-}
-
-static int ghash_setkey(struct crypto_shash *tfm,
-			const u8 *key, unsigned int keylen)
-{
-	struct s390_ghash_ctx *ctx = crypto_shash_ctx(tfm);
-
-	if (keylen != GHASH_BLOCK_SIZE)
-		return -EINVAL;
-
-	memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
-
-	return 0;
-}
-
-static int ghash_update(struct shash_desc *desc,
-			 const u8 *src, unsigned int srclen)
-{
-	struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
-	unsigned int n;
-
-	n = srclen & ~(GHASH_BLOCK_SIZE - 1);
-	cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n);
-	return srclen - n;
-}
-
-static void ghash_flush(struct s390_ghash_desc_ctx *dctx, const u8 *src,
-			unsigned int len)
-{
-	if (len) {
-		u8 buf[GHASH_BLOCK_SIZE] = {};
-
-		memcpy(buf, src, len);
-		cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE);
-		memzero_explicit(buf, sizeof(buf));
-	}
-}
-
-static int ghash_finup(struct shash_desc *desc, const u8 *src,
-		       unsigned int len, u8 *dst)
-{
-	struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
-
-	ghash_flush(dctx, src, len);
-	memcpy(dst, dctx->icv, GHASH_BLOCK_SIZE);
-	return 0;
-}
-
-static int ghash_export(struct shash_desc *desc, void *out)
-{
-	struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
-
-	memcpy(out, dctx->icv, GHASH_DIGEST_SIZE);
-	return 0;
-}
-
-static int ghash_import(struct shash_desc *desc, const void *in)
-{
-	struct s390_ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
-	struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
-
-	memcpy(dctx->icv, in, GHASH_DIGEST_SIZE);
-	memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE);
-	return 0;
-}
-
-static struct shash_alg ghash_alg = {
-	.digestsize	= GHASH_DIGEST_SIZE,
-	.init		= ghash_init,
-	.update		= ghash_update,
-	.finup		= ghash_finup,
-	.setkey		= ghash_setkey,
-	.export		= ghash_export,
-	.import		= ghash_import,
-	.statesize	= sizeof(struct ghash_desc_ctx),
-	.descsize	= sizeof(struct s390_ghash_desc_ctx),
-	.base		= {
-		.cra_name		= "ghash",
-		.cra_driver_name	= "ghash-s390",
-		.cra_priority		= 300,
-		.cra_flags		= CRYPTO_AHASH_ALG_BLOCK_ONLY,
-		.cra_blocksize		= GHASH_BLOCK_SIZE,
-		.cra_ctxsize		= sizeof(struct s390_ghash_ctx),
-		.cra_module		= THIS_MODULE,
-	},
-};
-
-static int __init ghash_mod_init(void)
-{
-	if (!cpacf_query_func(CPACF_KIMD, CPACF_KIMD_GHASH))
-		return -ENODEV;
-
-	return crypto_register_shash(&ghash_alg);
-}
-
-static void __exit ghash_mod_exit(void)
-{
-	crypto_unregister_shash(&ghash_alg);
-}
-
-module_cpu_feature_match(S390_CPU_FEATURE_MSA, ghash_mod_init);
-module_exit(ghash_mod_exit);
-
-MODULE_ALIAS_CRYPTO("ghash");
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("GHASH hash function, s390 implementation");