[RFC PATCH 02/20] crypto: x86/chacha - expose SIMD ChaCha routine as library function

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

Wire the existing x86 SIMD ChaCha code into the new ChaCha library
interface.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/crypto/chacha_glue.c | 14 ++++++++++++++
 crypto/Kconfig                |  1 +
 include/crypto/chacha.h       |  9 +++++++++
 3 files changed, 24 insertions(+)

diff --git a/arch/x86/crypto/chacha_glue.c b/arch/x86/crypto/chacha_glue.c
index bc62daa8dafd..1ea31d77fa00 100644
--- a/arch/x86/crypto/chacha_glue.c
+++ b/arch/x86/crypto/chacha_glue.c
@@ -123,6 +123,20 @@ static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
 	}
 }
 
+void chacha_crypt(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
+		  int nrounds)
+{
+	state = PTR_ALIGN(state, CHACHA_STATE_ALIGN);
+
+	if (bytes <= CHACHA_BLOCK_SIZE || !crypto_simd_usable())
+		return chacha_crypt_generic(state, dst, src, bytes, nrounds);
+
+	kernel_fpu_begin();
+	chacha_dosimd(state, dst, src, bytes, nrounds);
+	kernel_fpu_end();
+}
+EXPORT_SYMBOL(chacha_crypt);
+
 static int chacha_simd_stream_xor(struct skcipher_walk *walk,
 				  const struct chacha_ctx *ctx, const u8 *iv)
 {
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 5826381aca3a..780d080fc5ec 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1408,6 +1408,7 @@ config CRYPTO_CHACHA20_X86_64
 	depends on X86 && 64BIT
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_CHACHA20
+	select CRYPTO_ARCH_HAVE_LIB_CHACHA
 	help
 	  SSSE3, AVX2, and AVX-512VL optimized implementations of the ChaCha20,
 	  XChaCha20, and XChaCha12 stream ciphers.
diff --git a/include/crypto/chacha.h b/include/crypto/chacha.h
index c29d8f7d69ed..23747b20d470 100644
--- a/include/crypto/chacha.h
+++ b/include/crypto/chacha.h
@@ -25,6 +25,12 @@
 #define CHACHA_BLOCK_SIZE	64
 #define CHACHAPOLY_IV_SIZE	12
 
+#ifdef CONFIG_X86_64
+#define CHACHA_STATE_WORDS	((CHACHA_BLOCK_SIZE + 12) / sizeof(u32))
+#else
+#define CHACHA_STATE_WORDS	(CHACHA_BLOCK_SIZE / sizeof(u32))
+#endif
+
 /* 192-bit nonce, then 64-bit stream position */
 #define XCHACHA_IV_SIZE		32
 
@@ -57,6 +63,9 @@ static inline void chacha_init_generic(u32 *state, const u32 *key, const u8 *iv)
 
 static inline void chacha_init(u32 *state, const u32 *key, const u8 *iv)
 {
+	if (IS_ENABLED(CONFIG_X86_64))
+		state = PTR_ALIGN(state, 16);
+
 	chacha_init_generic(state, key, iv);
 }
 
-- 
2.17.1