Move the existing shared ChaCha code into lib/crypto, and at the
same time, split the support header into a public version, and an
internal version that is only intended for consumption by crypto
implementations.

While at it, tidy up lib/crypto/Makefile a bit so we are ready for
some new arrivals.

Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
---
 arch/arm/crypto/chacha-neon-glue.c   |  2 +-
 arch/arm64/crypto/chacha-neon-glue.c |  2 +-
 arch/x86/crypto/chacha_glue.c        |  2 +-
 crypto/chacha_generic.c              | 42 ++------------------
 include/crypto/chacha.h              | 37 ++++++++++-------
 include/crypto/internal/chacha.h     | 25 ++++++++++++
 lib/Makefile                         |  3 +-
 lib/crypto/Makefile                  | 19 +++++----
 lib/{ => crypto}/chacha.c            | 23 +++++++++++
 9 files changed, 89 insertions(+), 66 deletions(-)

diff --git a/arch/arm/crypto/chacha-neon-glue.c 
b/arch/arm/crypto/chacha-neon-glue.c
index a8e9b534c8da..26576772f18b 100644
--- a/arch/arm/crypto/chacha-neon-glue.c
+++ b/arch/arm/crypto/chacha-neon-glue.c
@@ -20,7 +20,7 @@
  */
 
 #include <crypto/algapi.h>
-#include <crypto/chacha.h>
+#include <crypto/internal/chacha.h>
 #include <crypto/internal/simd.h>
 #include <crypto/internal/skcipher.h>
 #include <linux/kernel.h>
diff --git a/arch/arm64/crypto/chacha-neon-glue.c 
b/arch/arm64/crypto/chacha-neon-glue.c
index 1495d2b18518..d4cc61bfe79d 100644
--- a/arch/arm64/crypto/chacha-neon-glue.c
+++ b/arch/arm64/crypto/chacha-neon-glue.c
@@ -20,7 +20,7 @@
  */
 
 #include <crypto/algapi.h>
-#include <crypto/chacha.h>
+#include <crypto/internal/chacha.h>
 #include <crypto/internal/simd.h>
 #include <crypto/internal/skcipher.h>
 #include <linux/kernel.h>
diff --git a/arch/x86/crypto/chacha_glue.c b/arch/x86/crypto/chacha_glue.c
index 388f95a4ec24..bc62daa8dafd 100644
--- a/arch/x86/crypto/chacha_glue.c
+++ b/arch/x86/crypto/chacha_glue.c
@@ -7,7 +7,7 @@
  */
 
 #include <crypto/algapi.h>
-#include <crypto/chacha.h>
+#include <crypto/internal/chacha.h>
 #include <crypto/internal/simd.h>
 #include <crypto/internal/skcipher.h>
 #include <linux/kernel.h>
diff --git a/crypto/chacha_generic.c b/crypto/chacha_generic.c
index 085d8d219987..0a0847eacfc8 100644
--- a/crypto/chacha_generic.c
+++ b/crypto/chacha_generic.c
@@ -8,29 +8,10 @@
 
 #include <asm/unaligned.h>
 #include <crypto/algapi.h>
-#include <crypto/chacha.h>
+#include <crypto/internal/chacha.h>
 #include <crypto/internal/skcipher.h>
 #include <linux/module.h>
 
-static void chacha_docrypt(u32 *state, u8 *dst, const u8 *src,
-                          unsigned int bytes, int nrounds)
-{
-       /* aligned to potentially speed up crypto_xor() */
-       u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long));
-
-       while (bytes >= CHACHA_BLOCK_SIZE) {
-               chacha_block(state, stream, nrounds);
-               crypto_xor_cpy(dst, src, stream, CHACHA_BLOCK_SIZE);
-               bytes -= CHACHA_BLOCK_SIZE;
-               dst += CHACHA_BLOCK_SIZE;
-               src += CHACHA_BLOCK_SIZE;
-       }
-       if (bytes) {
-               chacha_block(state, stream, nrounds);
-               crypto_xor_cpy(dst, src, stream, bytes);
-       }
-}
-
 static int chacha_stream_xor(struct skcipher_request *req,
                             const struct chacha_ctx *ctx, const u8 *iv)
 {
@@ -48,8 +29,8 @@ static int chacha_stream_xor(struct skcipher_request *req,
                if (nbytes < walk.total)
                        nbytes = round_down(nbytes, CHACHA_BLOCK_SIZE);
 
-               chacha_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
-                              nbytes, ctx->nrounds);
+               chacha_crypt(state, walk.dst.virt.addr, walk.src.virt.addr,
+                            nbytes, ctx->nrounds);
                err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
        }
 
@@ -58,22 +39,7 @@ static int chacha_stream_xor(struct skcipher_request *req,
 
 void crypto_chacha_init(u32 *state, const struct chacha_ctx *ctx, const u8 *iv)
 {
-       state[0]  = 0x61707865; /* "expa" */
-       state[1]  = 0x3320646e; /* "nd 3" */
-       state[2]  = 0x79622d32; /* "2-by" */
-       state[3]  = 0x6b206574; /* "te k" */
-       state[4]  = ctx->key[0];
-       state[5]  = ctx->key[1];
-       state[6]  = ctx->key[2];
-       state[7]  = ctx->key[3];
-       state[8]  = ctx->key[4];
-       state[9]  = ctx->key[5];
-       state[10] = ctx->key[6];
-       state[11] = ctx->key[7];
-       state[12] = get_unaligned_le32(iv +  0);
-       state[13] = get_unaligned_le32(iv +  4);
-       state[14] = get_unaligned_le32(iv +  8);
-       state[15] = get_unaligned_le32(iv + 12);
+       chacha_init(state, ctx->key, iv);
 }
 EXPORT_SYMBOL_GPL(crypto_chacha_init);
 
diff --git a/include/crypto/chacha.h b/include/crypto/chacha.h
index d1e723c6a37d..b2aaf711f2e7 100644
--- a/include/crypto/chacha.h
+++ b/include/crypto/chacha.h
@@ -15,9 +15,8 @@
 #ifndef _CRYPTO_CHACHA_H
 #define _CRYPTO_CHACHA_H
 
-#include <crypto/skcipher.h>
+#include <asm/unaligned.h>
 #include <linux/types.h>
-#include <linux/crypto.h>
 
 /* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */
 #define CHACHA_IV_SIZE         16
@@ -29,11 +28,6 @@
 /* 192-bit nonce, then 64-bit stream position */
 #define XCHACHA_IV_SIZE                32
 
-struct chacha_ctx {
-       u32 key[8];
-       int nrounds;
-};
-
 void chacha_block(u32 *state, u8 *stream, int nrounds);
 static inline void chacha20_block(u32 *state, u8 *stream)
 {
@@ -41,14 +35,27 @@ static inline void chacha20_block(u32 *state, u8 *stream)
 }
 void hchacha_block(const u32 *in, u32 *out, int nrounds);
 
-void crypto_chacha_init(u32 *state, const struct chacha_ctx *ctx, const u8 
*iv);
-
-int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
-                          unsigned int keysize);
-int crypto_chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key,
-                          unsigned int keysize);
+static inline void chacha_init(u32 *state, const u32 *key, const u8 *iv)
+{
+       state[0]  = 0x61707865; /* "expa" */
+       state[1]  = 0x3320646e; /* "nd 3" */
+       state[2]  = 0x79622d32; /* "2-by" */
+       state[3]  = 0x6b206574; /* "te k" */
+       state[4]  = key[0];
+       state[5]  = key[1];
+       state[6]  = key[2];
+       state[7]  = key[3];
+       state[8]  = key[4];
+       state[9]  = key[5];
+       state[10] = key[6];
+       state[11] = key[7];
+       state[12] = get_unaligned_le32(iv +  0);
+       state[13] = get_unaligned_le32(iv +  4);
+       state[14] = get_unaligned_le32(iv +  8);
+       state[15] = get_unaligned_le32(iv + 12);
+}
 
-int crypto_chacha_crypt(struct skcipher_request *req);
-int crypto_xchacha_crypt(struct skcipher_request *req);
+void chacha_crypt(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
+                 int nrounds);
 
 #endif /* _CRYPTO_CHACHA_H */
diff --git a/include/crypto/internal/chacha.h b/include/crypto/internal/chacha.h
new file mode 100644
index 000000000000..f7ffe0f3fa47
--- /dev/null
+++ b/include/crypto/internal/chacha.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _CRYPTO_INTERNAL_CHACHA_H
+#define _CRYPTO_INTERNAL_CHACHA_H
+
+#include <crypto/chacha.h>
+#include <crypto/skcipher.h>
+#include <linux/crypto.h>
+
+struct chacha_ctx {
+       u32 key[8];
+       int nrounds;
+};
+
+void crypto_chacha_init(u32 *state, const struct chacha_ctx *ctx, const u8 
*iv);
+
+int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
+                          unsigned int keysize);
+int crypto_chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key,
+                          unsigned int keysize);
+
+int crypto_chacha_crypt(struct skcipher_request *req);
+int crypto_xchacha_crypt(struct skcipher_request *req);
+
+#endif /* _CRYPTO_CHACHA_H */
diff --git a/lib/Makefile b/lib/Makefile
index 29c02a924973..1436c9608fdb 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -30,8 +30,7 @@ endif
 
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
         rbtree.o radix-tree.o timerqueue.o xarray.o \
-        idr.o extable.o \
-        sha1.o chacha.o irq_regs.o argv_split.o \
+        idr.o extable.o sha1.o irq_regs.o argv_split.o \
         flex_proportions.o ratelimit.o show_mem.o \
         is_single_threaded.o plist.o decompress.o kobject_uevent.o \
         earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
index cbe0b6a6450d..24dad058f2ae 100644
--- a/lib/crypto/Makefile
+++ b/lib/crypto/Makefile
@@ -1,13 +1,16 @@
 # SPDX-License-Identifier: GPL-2.0
 
-obj-$(CONFIG_CRYPTO_LIB_AES) += libaes.o
-libaes-y := aes.o
+# chacha is used by the /dev/random driver which is always builtin
+obj-y                                          += chacha.o
 
-obj-$(CONFIG_CRYPTO_LIB_ARC4) += libarc4.o
-libarc4-y := arc4.o
+obj-$(CONFIG_CRYPTO_LIB_AES)                   += libaes.o
+libaes-y                                       := aes.o
 
-obj-$(CONFIG_CRYPTO_LIB_DES) += libdes.o
-libdes-y := des.o
+obj-$(CONFIG_CRYPTO_LIB_ARC4)                  += libarc4.o
+libarc4-y                                      := arc4.o
 
-obj-$(CONFIG_CRYPTO_LIB_SHA256) += libsha256.o
-libsha256-y := sha256.o
+obj-$(CONFIG_CRYPTO_LIB_DES)                   += libdes.o
+libdes-y                                       := des.o
+
+obj-$(CONFIG_CRYPTO_LIB_SHA256)                        += libsha256.o
+libsha256-y                                    := sha256.o
diff --git a/lib/chacha.c b/lib/crypto/chacha.c
similarity index 85%
rename from lib/chacha.c
rename to lib/crypto/chacha.c
index c7c9826564d3..429adac51f66 100644
--- a/lib/chacha.c
+++ b/lib/crypto/chacha.c
@@ -5,11 +5,14 @@
  * Copyright (C) 2015 Martin Willi
  */
 
+#include <linux/bug.h>
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/bitops.h>
+#include <linux/string.h>
 #include <linux/cryptohash.h>
 #include <asm/unaligned.h>
+#include <crypto/algapi.h> // for crypto_xor_cpy
 #include <crypto/chacha.h>
 
 static void chacha_permute(u32 *x, int nrounds)
@@ -111,3 +114,23 @@ void hchacha_block(const u32 *in, u32 *out, int nrounds)
        memcpy(&out[4], &x[12], 16);
 }
 EXPORT_SYMBOL(hchacha_block);
+
+void chacha_crypt(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
+                 int nrounds)
+{
+       /* aligned to potentially speed up crypto_xor() */
+       u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long));
+
+       while (bytes >= CHACHA_BLOCK_SIZE) {
+               chacha_block(state, stream, nrounds);
+               crypto_xor_cpy(dst, src, stream, CHACHA_BLOCK_SIZE);
+               bytes -= CHACHA_BLOCK_SIZE;
+               dst += CHACHA_BLOCK_SIZE;
+               src += CHACHA_BLOCK_SIZE;
+       }
+       if (bytes) {
+               chacha_block(state, stream, nrounds);
+               crypto_xor_cpy(dst, src, stream, bytes);
+       }
+}
+EXPORT_SYMBOL(chacha_crypt);
-- 
2.20.1

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