diff --git a/include/crypto/gf128hash.h b/include/crypto/gf128hash.h
index 5ffa86f5c13f..1052041e3499 100644
--- a/include/crypto/gf128hash.h
+++ b/include/crypto/gf128hash.h
@@ -44,20 +44,14 @@ struct polyval_elem {
  * exponentiation repeats the POLYVAL dot operation, with its "extra" x^-128.
  */
 struct polyval_key {
-#ifdef CONFIG_CRYPTO_LIB_GF128HASH_ARCH
-#ifdef CONFIG_ARM64
-	/** @h_powers: Powers of the hash key H^8 through H^1 */
-	struct polyval_elem h_powers[8];
-#elif defined(CONFIG_X86)
+#if defined(CONFIG_CRYPTO_LIB_GF128HASH_ARCH) && \
+	(defined(CONFIG_ARM64) || defined(CONFIG_X86))
 	/** @h_powers: Powers of the hash key H^8 through H^1 */
 	struct polyval_elem h_powers[8];
 #else
-#error "Unhandled arch"
-#endif
-#else /* CONFIG_CRYPTO_LIB_GF128HASH_ARCH */
 	/** @h: The hash key H */
 	struct polyval_elem h;
-#endif /* !CONFIG_CRYPTO_LIB_GF128HASH_ARCH */
+#endif
 };
 
 /**
@@ -84,19 +78,9 @@ struct polyval_ctx {
  *
  * Context: Any context.
  */
-#ifdef CONFIG_CRYPTO_LIB_GF128HASH_ARCH
 void polyval_preparekey(struct polyval_key *key,
 			const u8 raw_key[POLYVAL_BLOCK_SIZE]);
 
-#else
-static inline void polyval_preparekey(struct polyval_key *key,
-				      const u8 raw_key[POLYVAL_BLOCK_SIZE])
-{
-	/* Just a simple copy, so inline it. */
-	memcpy(key->h.bytes, raw_key, POLYVAL_BLOCK_SIZE);
-}
-#endif
-
 /**
  * polyval_init() - Initialize a POLYVAL context for a new message
  * @ctx: The context to initialize
diff --git a/lib/crypto/arm64/gf128hash.h b/lib/crypto/arm64/gf128hash.h
index c1012007adcf..796c36804dda 100644
--- a/lib/crypto/arm64/gf128hash.h
+++ b/lib/crypto/arm64/gf128hash.h
@@ -17,6 +17,7 @@ asmlinkage void polyval_blocks_pmull(struct polyval_elem *acc,
 				     const struct polyval_key *key,
 				     const u8 *data, size_t nblocks);
 
+#define polyval_preparekey_arch polyval_preparekey_arch
 static void polyval_preparekey_arch(struct polyval_key *key,
 				    const u8 raw_key[POLYVAL_BLOCK_SIZE])
 {
@@ -40,6 +41,7 @@ static void polyval_preparekey_arch(struct polyval_key *key,
 	}
 }
 
+#define polyval_mul_arch polyval_mul_arch
 static void polyval_mul_arch(struct polyval_elem *acc,
 			     const struct polyval_key *key)
 {
@@ -51,6 +53,7 @@ static void polyval_mul_arch(struct polyval_elem *acc,
 	}
 }
 
+#define polyval_blocks_arch polyval_blocks_arch
 static void polyval_blocks_arch(struct polyval_elem *acc,
 				const struct polyval_key *key,
 				const u8 *data, size_t nblocks)
diff --git a/lib/crypto/gf128hash.c b/lib/crypto/gf128hash.c
index 8bb848bf26b7..05f44a9193f7 100644
--- a/lib/crypto/gf128hash.c
+++ b/lib/crypto/gf128hash.c
@@ -217,16 +217,20 @@ polyval_blocks_generic(struct polyval_elem *acc, const struct polyval_elem *key,
 	} while (--nblocks);
 }
 
-/* Include the arch-optimized implementation of POLYVAL, if one is available. */
 #ifdef CONFIG_CRYPTO_LIB_GF128HASH_ARCH
 #include "gf128hash.h" /* $(SRCARCH)/gf128hash.h */
+#endif
+
 void polyval_preparekey(struct polyval_key *key,
 			const u8 raw_key[POLYVAL_BLOCK_SIZE])
 {
+#ifdef polyval_preparekey_arch
 	polyval_preparekey_arch(key, raw_key);
+#else
+	memcpy(key->h.bytes, raw_key, POLYVAL_BLOCK_SIZE);
+#endif
 }
 EXPORT_SYMBOL_GPL(polyval_preparekey);
-#endif /* Else, polyval_preparekey() is an inline function. */
 
 /*
  * polyval_mul_generic() and polyval_blocks_generic() take the key as a
@@ -238,8 +242,12 @@ EXPORT_SYMBOL_GPL(polyval_preparekey);
 
 static void polyval_mul(struct polyval_ctx *ctx)
 {
-#ifdef CONFIG_CRYPTO_LIB_GF128HASH_ARCH
+#ifdef polyval_mul_arch
 	polyval_mul_arch(&ctx->acc, ctx->key);
+#elif defined(polyval_blocks_arch)
+	static const u8 zeroes[POLYVAL_BLOCK_SIZE];
+
+	polyval_blocks_arch(&ctx->acc, ctx->key, zeroes, 1);
 #else
 	polyval_mul_generic(&ctx->acc, &ctx->key->h);
 #endif
@@ -248,7 +256,7 @@ static void polyval_mul(struct polyval_ctx *ctx)
 static void polyval_blocks(struct polyval_ctx *ctx,
 			   const u8 *data, size_t nblocks)
 {
-#ifdef CONFIG_CRYPTO_LIB_GF128HASH_ARCH
+#ifdef polyval_blocks_arch
 	polyval_blocks_arch(&ctx->acc, ctx->key, data, nblocks);
 #else
 	polyval_blocks_generic(&ctx->acc, &ctx->key->h, data, nblocks);
diff --git a/lib/crypto/x86/gf128hash.h b/lib/crypto/x86/gf128hash.h
index fe506cf6431b..adf6147ea677 100644
--- a/lib/crypto/x86/gf128hash.h
+++ b/lib/crypto/x86/gf128hash.h
@@ -17,6 +17,7 @@ asmlinkage void polyval_blocks_pclmul_avx(struct polyval_elem *acc,
 					  const struct polyval_key *key,
 					  const u8 *data, size_t nblocks);
 
+#define polyval_preparekey_arch polyval_preparekey_arch
 static void polyval_preparekey_arch(struct polyval_key *key,
 				    const u8 raw_key[POLYVAL_BLOCK_SIZE])
 {
@@ -40,6 +41,7 @@ static void polyval_preparekey_arch(struct polyval_key *key,
 	}
 }
 
+#define polyval_mul_arch polyval_mul_arch
 static void polyval_mul_arch(struct polyval_elem *acc,
 			     const struct polyval_key *key)
 {
@@ -52,6 +54,7 @@ static void polyval_mul_arch(struct polyval_elem *acc,
 	}
 }
 
+#define polyval_blocks_arch polyval_blocks_arch
 static void polyval_blocks_arch(struct polyval_elem *acc,
 				const struct polyval_key *key,
 				const u8 *data, size_t nblocks)