[PATCH 6/9] crypto: powerpc/chacha - remove the skcipher algorithms

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

Since crypto/chacha.c now registers chacha20-$(ARCH), xchacha20-$(ARCH),
and xchacha12-$(ARCH) skcipher algorithms that use the architecture's
ChaCha and HChaCha library functions, individual architectures no longer
need to do the same.  Therefore, remove the redundant skcipher
algorithms and leave just the library functions.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 arch/powerpc/crypto/Kconfig           |   8 --
 arch/powerpc/crypto/chacha-p10-glue.c | 145 ++------------------------
 2 files changed, 6 insertions(+), 147 deletions(-)

diff --git a/arch/powerpc/crypto/Kconfig b/arch/powerpc/crypto/Kconfig
index 370db8192ce62..47dccdd496374 100644
--- a/arch/powerpc/crypto/Kconfig
+++ b/arch/powerpc/crypto/Kconfig
@@ -93,21 +93,13 @@ config CRYPTO_AES_GCM_P10
 	  later CPU. This module supports stitched acceleration for AES/GCM.
 
 config CRYPTO_CHACHA20_P10
 	tristate
 	depends on PPC64 && CPU_LITTLE_ENDIAN && VSX
-	select CRYPTO_SKCIPHER
 	select CRYPTO_LIB_CHACHA_GENERIC
 	select CRYPTO_ARCH_HAVE_LIB_CHACHA
 	default CRYPTO_LIB_CHACHA_INTERNAL
-	help
-	  Length-preserving ciphers: ChaCha20, XChaCha20, and XChaCha12
-	  stream cipher algorithms
-
-	  Architecture: PowerPC64
-	  - Power10 or later
-	  - Little-endian
 
 config CRYPTO_POLY1305_P10
 	tristate "Hash functions: Poly1305 (P10 or later)"
 	depends on PPC64 && CPU_LITTLE_ENDIAN && VSX
 	select CRYPTO_HASH
diff --git a/arch/powerpc/crypto/chacha-p10-glue.c b/arch/powerpc/crypto/chacha-p10-glue.c
index 3355305b6c7f8..9982929573add 100644
--- a/arch/powerpc/crypto/chacha-p10-glue.c
+++ b/arch/powerpc/crypto/chacha-p10-glue.c
@@ -1,17 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * PowerPC P10 (ppc64le) accelerated ChaCha and XChaCha stream ciphers,
- * including ChaCha20 (RFC7539)
+ * ChaCha stream cipher (P10 accelerated)
  *
  * Copyright 2023- IBM Corp. All rights reserved.
  */
 
-#include <crypto/algapi.h>
-#include <crypto/internal/chacha.h>
+#include <crypto/chacha.h>
 #include <crypto/internal/simd.h>
-#include <crypto/internal/skcipher.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/cpufeature.h>
 #include <linux/sizes.h>
 #include <asm/simd.h>
@@ -76,152 +73,22 @@ void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
 		dst += todo;
 	} while (bytes);
 }
 EXPORT_SYMBOL(chacha_crypt_arch);
 
-static int chacha_p10_stream_xor(struct skcipher_request *req,
-				 const struct chacha_ctx *ctx, const u8 *iv)
-{
-	struct skcipher_walk walk;
-	u32 state[16];
-	int err;
-
-	err = skcipher_walk_virt(&walk, req, false);
-	if (err)
-		return err;
-
-	chacha_init(state, ctx->key, iv);
-
-	while (walk.nbytes > 0) {
-		unsigned int nbytes = walk.nbytes;
-
-		if (nbytes < walk.total)
-			nbytes = rounddown(nbytes, walk.stride);
-
-		if (!crypto_simd_usable()) {
-			chacha_crypt_generic(state, walk.dst.virt.addr,
-					     walk.src.virt.addr, nbytes,
-					     ctx->nrounds);
-		} else {
-			vsx_begin();
-			chacha_p10_do_8x(state, walk.dst.virt.addr,
-				      walk.src.virt.addr, nbytes, ctx->nrounds);
-			vsx_end();
-		}
-		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
-		if (err)
-			break;
-	}
-
-	return err;
-}
-
-static int chacha_p10(struct skcipher_request *req)
-{
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
-
-	return chacha_p10_stream_xor(req, ctx, req->iv);
-}
-
-static int xchacha_p10(struct skcipher_request *req)
-{
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
-	struct chacha_ctx subctx;
-	u32 state[16];
-	u8 real_iv[16];
-
-	chacha_init(state, ctx->key, req->iv);
-	hchacha_block_arch(state, subctx.key, ctx->nrounds);
-	subctx.nrounds = ctx->nrounds;
-
-	memcpy(&real_iv[0], req->iv + 24, 8);
-	memcpy(&real_iv[8], req->iv + 16, 8);
-	return chacha_p10_stream_xor(req, &subctx, real_iv);
-}
-
-static struct skcipher_alg algs[] = {
-	{
-		.base.cra_name		= "chacha20",
-		.base.cra_driver_name	= "chacha20-p10",
-		.base.cra_priority	= 300,
-		.base.cra_blocksize	= 1,
-		.base.cra_ctxsize	= sizeof(struct chacha_ctx),
-		.base.cra_module	= THIS_MODULE,
-
-		.min_keysize		= CHACHA_KEY_SIZE,
-		.max_keysize		= CHACHA_KEY_SIZE,
-		.ivsize			= CHACHA_IV_SIZE,
-		.chunksize		= CHACHA_BLOCK_SIZE,
-		.setkey			= chacha20_setkey,
-		.encrypt		= chacha_p10,
-		.decrypt		= chacha_p10,
-	}, {
-		.base.cra_name		= "xchacha20",
-		.base.cra_driver_name	= "xchacha20-p10",
-		.base.cra_priority	= 300,
-		.base.cra_blocksize	= 1,
-		.base.cra_ctxsize	= sizeof(struct chacha_ctx),
-		.base.cra_module	= THIS_MODULE,
-
-		.min_keysize		= CHACHA_KEY_SIZE,
-		.max_keysize		= CHACHA_KEY_SIZE,
-		.ivsize			= XCHACHA_IV_SIZE,
-		.chunksize		= CHACHA_BLOCK_SIZE,
-		.setkey			= chacha20_setkey,
-		.encrypt		= xchacha_p10,
-		.decrypt		= xchacha_p10,
-	}, {
-		.base.cra_name		= "xchacha12",
-		.base.cra_driver_name	= "xchacha12-p10",
-		.base.cra_priority	= 300,
-		.base.cra_blocksize	= 1,
-		.base.cra_ctxsize	= sizeof(struct chacha_ctx),
-		.base.cra_module	= THIS_MODULE,
-
-		.min_keysize		= CHACHA_KEY_SIZE,
-		.max_keysize		= CHACHA_KEY_SIZE,
-		.ivsize			= XCHACHA_IV_SIZE,
-		.chunksize		= CHACHA_BLOCK_SIZE,
-		.setkey			= chacha12_setkey,
-		.encrypt		= xchacha_p10,
-		.decrypt		= xchacha_p10,
-	}
-};
-
 bool chacha_is_arch_optimized(void)
 {
 	return static_key_enabled(&have_p10);
 }
 EXPORT_SYMBOL(chacha_is_arch_optimized);
 
 static int __init chacha_p10_init(void)
 {
-	if (!cpu_has_feature(CPU_FTR_ARCH_31))
-		return 0;
-
-	static_branch_enable(&have_p10);
-
-	return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
-}
-
-static void __exit chacha_p10_exit(void)
-{
-	if (!static_branch_likely(&have_p10))
-		return;
-
-	crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
+	if (cpu_has_feature(CPU_FTR_ARCH_31))
+		static_branch_enable(&have_p10);
+	return 0;
 }
-
 arch_initcall(chacha_p10_init);
-module_exit(chacha_p10_exit);
 
-MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (P10 accelerated)");
+MODULE_DESCRIPTION("ChaCha stream cipher (P10 accelerated)");
 MODULE_AUTHOR("Danny Tsen <dtsen@linux.ibm.com>");
 MODULE_LICENSE("GPL v2");
-MODULE_ALIAS_CRYPTO("chacha20");
-MODULE_ALIAS_CRYPTO("chacha20-p10");
-MODULE_ALIAS_CRYPTO("xchacha20");
-MODULE_ALIAS_CRYPTO("xchacha20-p10");
-MODULE_ALIAS_CRYPTO("xchacha12");
-MODULE_ALIAS_CRYPTO("xchacha12-p10");
-- 
2.49.0