To reduce the number of copies of boilerplate code throughout
the tree, this patch implements generic glue for the SHA-256
algorithm. This allows a specific arch or hardware implementation
to only implement the special handling that it needs.

Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
---
 crypto/Kconfig       |   4 ++
 crypto/Makefile      |   1 +
 crypto/sha256_base.c | 140 +++++++++++++++++++++++++++++++++++++++++++++++++++
 include/crypto/sha.h |  17 +++++++
 4 files changed, 162 insertions(+)
 create mode 100644 crypto/sha256_base.c

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 3400cf4e3cdb..1664bd68b97d 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -602,6 +602,10 @@ config CRYPTO_SHA1_MB
          lanes remain unfilled, a flush operation will be initiated to
          process the crypto jobs, adding a slight latency.
 
+
+config CRYPTO_SHA256_BASE
+       tristate
+
 config CRYPTO_SHA256
        tristate "SHA224 and SHA256 digest algorithm"
        select CRYPTO_HASH
diff --git a/crypto/Makefile b/crypto/Makefile
index 6174bf2592fe..bb9bafeb3ac7 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_CRYPTO_RMD160) += rmd160.o
 obj-$(CONFIG_CRYPTO_RMD256) += rmd256.o
 obj-$(CONFIG_CRYPTO_RMD320) += rmd320.o
 obj-$(CONFIG_CRYPTO_SHA1) += sha1_generic.o
+obj-$(CONFIG_CRYPTO_SHA256_BASE) += sha256_base.o
 obj-$(CONFIG_CRYPTO_SHA256) += sha256_generic.o
 obj-$(CONFIG_CRYPTO_SHA512_BASE) += sha512_base.o
 obj-$(CONFIG_CRYPTO_SHA512) += sha512_generic.o
diff --git a/crypto/sha256_base.c b/crypto/sha256_base.c
new file mode 100644
index 000000000000..5fd728066912
--- /dev/null
+++ b/crypto/sha256_base.c
@@ -0,0 +1,140 @@
+/*
+ * sha256_base.c - core logic for SHA-256 implementations
+ *
+ * Copyright (C) 2015 Linaro Ltd <ard.biesheu...@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <crypto/internal/hash.h>
+#include <crypto/sha.h>
+#include <linux/crypto.h>
+#include <linux/module.h>
+
+#include <asm/unaligned.h>
+
+int crypto_sha224_base_init(struct shash_desc *desc)
+{
+       static const u32 sha224_init_state[] = {
+               SHA224_H0, SHA224_H1, SHA224_H2, SHA224_H3,
+               SHA224_H4, SHA224_H5, SHA224_H6, SHA224_H7,
+       };
+       struct sha256_state *sctx = shash_desc_ctx(desc);
+
+       memcpy(sctx->state, sha224_init_state, sizeof(sctx->state));
+       sctx->count = 0;
+       return 0;
+}
+EXPORT_SYMBOL(crypto_sha224_base_init);
+
+int crypto_sha256_base_init(struct shash_desc *desc)
+{
+       static const u32 sha256_init_state[] = {
+               SHA256_H0, SHA256_H1, SHA256_H2, SHA256_H3,
+               SHA256_H4, SHA256_H5, SHA256_H6, SHA256_H7,
+       };
+       struct sha256_state *sctx = shash_desc_ctx(desc);
+
+       memcpy(sctx->state, sha256_init_state, sizeof(sctx->state));
+       sctx->count = 0;
+       return 0;
+}
+EXPORT_SYMBOL(crypto_sha256_base_init);
+
+int crypto_sha256_base_export(struct shash_desc *desc, void *out)
+{
+       struct sha256_state *sctx = shash_desc_ctx(desc);
+       struct sha256_state *dst = out;
+
+       *dst = *sctx;
+
+       return 0;
+}
+EXPORT_SYMBOL(crypto_sha256_base_export);
+
+int crypto_sha256_base_import(struct shash_desc *desc, const void *in)
+{
+       struct sha256_state *sctx = shash_desc_ctx(desc);
+       struct sha256_state const *src = in;
+
+       *sctx = *src;
+
+       return 0;
+}
+EXPORT_SYMBOL(crypto_sha256_base_import);
+
+int crypto_sha256_base_do_update(struct shash_desc *desc, const u8 *data,
+                                unsigned int len, sha256_block_fn *block_fn,
+                                void *p)
+{
+       struct sha256_state *sctx = shash_desc_ctx(desc);
+       unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
+
+       sctx->count += len;
+
+       if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
+               int blocks;
+
+               if (partial) {
+                       int p = SHA256_BLOCK_SIZE - partial;
+
+                       memcpy(sctx->buf + partial, data, p);
+                       data += p;
+                       len -= p;
+               }
+
+               blocks = len / SHA256_BLOCK_SIZE;
+               len %= SHA256_BLOCK_SIZE;
+
+               block_fn(blocks, data, sctx->state,
+                        partial ? sctx->buf : NULL, p);
+               data += blocks * SHA256_BLOCK_SIZE;
+               partial = 0;
+       }
+       if (len)
+               memcpy(sctx->buf + partial, data, len);
+
+       return 0;
+}
+EXPORT_SYMBOL(crypto_sha256_base_do_update);
+
+int crypto_sha256_base_do_finalize(struct shash_desc *desc,
+                                  sha256_block_fn *block_fn, void *p)
+{
+       const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
+       struct sha256_state *sctx = shash_desc_ctx(desc);
+       __be64 *bits = (__be64 *)(sctx->buf + bit_offset);
+       unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
+
+       sctx->buf[partial++] = 0x80;
+       if (partial > bit_offset) {
+               memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
+               partial = 0;
+
+               block_fn(1, sctx->buf, sctx->state, NULL, p);
+       }
+
+       memset(sctx->buf + partial, 0x0, bit_offset - partial);
+       *bits = cpu_to_be64(sctx->count << 3);
+       block_fn(1, sctx->buf, sctx->state, NULL, p);
+
+       return 0;
+}
+EXPORT_SYMBOL(crypto_sha256_base_do_finalize);
+
+int crypto_sha256_base_finish(struct shash_desc *desc, u8 *out)
+{
+       unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
+       struct sha256_state *sctx = shash_desc_ctx(desc);
+       __be32 *digest = (__be32 *)out;
+       int i;
+
+       for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
+               put_unaligned_be32(sctx->state[i], digest++);
+
+       *sctx = (struct sha256_state){};
+       return 0;
+}
+EXPORT_SYMBOL(crypto_sha256_base_finish);
diff --git a/include/crypto/sha.h b/include/crypto/sha.h
index 85997a17d4e2..0ed6630d7c40 100644
--- a/include/crypto/sha.h
+++ b/include/crypto/sha.h
@@ -82,6 +82,8 @@ struct sha512_state {
        u8 buf[SHA512_BLOCK_SIZE];
 };
 
+typedef void (sha256_block_fn)(int blocks, u8 const *src, u32 *state,
+                              const u8 *head, void *p);
 typedef void (sha512_block_fn)(int blocks, u8 const *src, u64 *state,
                               const u8 *head, void *p);
 
@@ -112,4 +114,19 @@ extern int crypto_sha512_base_do_finalize(struct 
shash_desc *desc,
 
 extern int crypto_sha512_base_finish(struct shash_desc *desc, u8 *out);
 
+extern int crypto_sha224_base_init(struct shash_desc *desc);
+extern int crypto_sha256_base_init(struct shash_desc *desc);
+
+extern int crypto_sha256_base_export(struct shash_desc *desc, void *out);
+extern int crypto_sha256_base_import(struct shash_desc *desc, const void *in);
+
+extern int crypto_sha256_base_do_update(struct shash_desc *desc, const u8 
*data,
+                                unsigned int len, sha256_block_fn *block_fn,
+                                void *p);
+
+extern int crypto_sha256_base_do_finalize(struct shash_desc *desc,
+                                  sha256_block_fn *block_fn, void *p);
+
+extern int crypto_sha256_base_finish(struct shash_desc *desc, u8 *out);
+
 #endif
-- 
1.8.3.2

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