[CRYPTO] padlock: Fix spurious ECB page fault

The xcryptecb instruction always processes an even number of blocks so
we need to ensure th existence of an extra block if we have to process
an odd number of blocks.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/padlock-aes.c

@@ -419,13 +419,58 @@ static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 /* ====== Encryption/decryption routines ====== */
 
 /* These are the real call to PadLock. */
+static inline void padlock_xcrypt(const u8 *input, u8 *output, void *key,
+				  void *control_word)
+{
+	asm volatile (".byte 0xf3,0x0f,0xa7,0xc8"	/* rep xcryptecb */
+		      : "+S"(input), "+D"(output)
+		      : "d"(control_word), "b"(key), "c"(1));
+}
+
+static void aes_crypt_copy(const u8 *in, u8 *out, u32 *key, struct cword *cword)
+{
+	u8 tmp[AES_BLOCK_SIZE * 2]
+		__attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
+
+	memcpy(tmp, in, AES_BLOCK_SIZE);
+	padlock_xcrypt(tmp, out, key, cword);
+}
+
+static inline void aes_crypt(const u8 *in, u8 *out, u32 *key,
+			     struct cword *cword)
+{
+	asm volatile ("pushfl; popfl");
+
+	/* padlock_xcrypt requires at least two blocks of data. */
+	if (unlikely(!(((unsigned long)in ^ (PAGE_SIZE - AES_BLOCK_SIZE)) &
+		       (PAGE_SIZE - 1)))) {
+		aes_crypt_copy(in, out, key, cword);
+		return;
+	}
+
+	padlock_xcrypt(in, out, key, cword);
+}
+
 static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key,
 				      void *control_word, u32 count)
 {
+	if (count == 1) {
+		aes_crypt(input, output, key, control_word);
+		return;
+	}
+
 	asm volatile ("pushfl; popfl");		/* enforce key reload. */
-	asm volatile (".byte 0xf3,0x0f,0xa7,0xc8"	/* rep xcryptecb */
+	asm volatile ("test $1, %%cl;"
+		      "je 1f;"
+		      "lea -1(%%ecx), %%eax;"
+		      "mov $1, %%ecx;"
+		      ".byte 0xf3,0x0f,0xa7,0xc8;"	/* rep xcryptecb */
+		      "mov %%eax, %%ecx;"
+		      "1:"
+		      ".byte 0xf3,0x0f,0xa7,0xc8"	/* rep xcryptecb */
 		      : "+S"(input), "+D"(output)
-		      : "d"(control_word), "b"(key), "c"(count));
+		      : "d"(control_word), "b"(key), "c"(count)
+		      : "ax");
 }
 
 static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
@@ -443,13 +488,13 @@ static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
 static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 {
 	struct aes_ctx *ctx = aes_ctx(tfm);
-	padlock_xcrypt_ecb(in, out, ctx->E, &ctx->cword.encrypt, 1);
+	aes_crypt(in, out, ctx->E, &ctx->cword.encrypt);
 }
 
 static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 {
 	struct aes_ctx *ctx = aes_ctx(tfm);
-	padlock_xcrypt_ecb(in, out, ctx->D, &ctx->cword.decrypt, 1);
+	aes_crypt(in, out, ctx->D, &ctx->cword.decrypt);
 }
 
 static struct crypto_alg aes_alg = {