crypto: vmx - Adding support for XTS

This patch add XTS support using VMX-crypto driver.

Signed-off-by: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com>
Signed-off-by: Paulo Flabiano Smorigo <pfsmorigo@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

3 files changed, 193 insertions, 1 deletions

diff --git a/drivers/crypto/vmx/Makefile b/drivers/crypto/vmx/Makefile
index d28ab96a2475..de6e241b0866 100644
--- a/drivers/crypto/vmx/Makefile
+++ b/drivers/crypto/vmx/Makefile
@@ -1,5 +1,5 @@
 obj-$(CONFIG_CRYPTO_DEV_VMX_ENCRYPT) += vmx-crypto.o
-vmx-crypto-objs := vmx.o aesp8-ppc.o ghashp8-ppc.o aes.o aes_cbc.o aes_ctr.o ghash.o
+vmx-crypto-objs := vmx.o aesp8-ppc.o ghashp8-ppc.o aes.o aes_cbc.o aes_ctr.o aes_xts.o ghash.o
 
 ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)
 TARGET := linux-ppc64le
diff --git a/drivers/crypto/vmx/aes_xts.c b/drivers/crypto/vmx/aes_xts.c
new file mode 100644
index 000000000000..cfb25413917c
--- /dev/null
+++ b/drivers/crypto/vmx/aes_xts.c
@@ -0,0 +1,190 @@
+/**
+ * AES XTS routines supporting VMX In-core instructions on Power 8
+ *
+ * Copyright (C) 2015 International Business Machines Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundations; version 2 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY of FITNESS FOR A PARTICUPAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Author: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com>
+ */
+
+#include <linux/types.h>
+#include <linux/err.h>
+#include <linux/crypto.h>
+#include <linux/delay.h>
+#include <linux/hardirq.h>
+#include <asm/switch_to.h>
+#include <crypto/aes.h>
+#include <crypto/scatterwalk.h>
+#include <crypto/xts.h>
+
+#include "aesp8-ppc.h"
+
+struct p8_aes_xts_ctx {
+        struct crypto_blkcipher *fallback;
+        struct aes_key enc_key;
+        struct aes_key dec_key;
+        struct aes_key tweak_key;
+};
+
+static int p8_aes_xts_init(struct crypto_tfm *tfm)
+{
+        const char *alg;
+        struct crypto_blkcipher *fallback;
+        struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
+
+        if (!(alg = crypto_tfm_alg_name(tfm))) {
+                printk(KERN_ERR "Failed to get algorithm name.\n");
+                return -ENOENT;
+        }
+
+        fallback =
+                crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
+        if (IS_ERR(fallback)) {
+                printk(KERN_ERR
+                        "Failed to allocate transformation for '%s': %ld\n",
+                        alg, PTR_ERR(fallback));
+                return PTR_ERR(fallback);
+        }
+        printk(KERN_INFO "Using '%s' as fallback implementation.\n",
+                crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));
+
+        crypto_blkcipher_set_flags(
+                fallback,
+                crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm));
+        ctx->fallback = fallback;
+
+        return 0;
+}
+
+static void p8_aes_xts_exit(struct crypto_tfm *tfm)
+{
+        struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
+
+        if (ctx->fallback) {
+                crypto_free_blkcipher(ctx->fallback);
+                ctx->fallback = NULL;
+        }
+}
+
+static int p8_aes_xts_setkey(struct crypto_tfm *tfm, const u8 *key,
+                             unsigned int keylen)
+{
+        int ret;
+        struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
+
+        ret = xts_check_key(tfm, key, keylen);
+        if (ret)
+                return ret;
+
+        preempt_disable();
+        pagefault_disable();
+        enable_kernel_vsx();
+        ret = aes_p8_set_encrypt_key(key + keylen/2, (keylen/2) * 8, &ctx->tweak_key);
+        ret += aes_p8_set_encrypt_key(key, (keylen/2) * 8, &ctx->enc_key);
+        ret += aes_p8_set_decrypt_key(key, (keylen/2) * 8, &ctx->dec_key);
+        disable_kernel_vsx();
+        pagefault_enable();
+        preempt_enable();
+
+        ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen);
+        return ret;
+}
+
+static int p8_aes_xts_crypt(struct blkcipher_desc *desc,
+                            struct scatterlist *dst,
+                            struct scatterlist *src,
+                            unsigned int nbytes, int enc)
+{
+        int ret;
+        u8 tweak[AES_BLOCK_SIZE];
+        u8 *iv;
+        struct blkcipher_walk walk;
+        struct p8_aes_xts_ctx *ctx =
+                crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
+        struct blkcipher_desc fallback_desc = {
+                .tfm = ctx->fallback,
+                .info = desc->info,
+                .flags = desc->flags
+        };
+
+        if (in_interrupt()) {
+                ret = enc ? crypto_blkcipher_encrypt(&fallback_desc, dst, src, nbytes) :
+                            crypto_blkcipher_decrypt(&fallback_desc, dst, src, nbytes);
+        } else {
+                preempt_disable();
+                pagefault_disable();
+                enable_kernel_vsx();
+
+                blkcipher_walk_init(&walk, dst, src, nbytes);
+
+                iv = (u8 *)walk.iv;
+                ret = blkcipher_walk_virt(desc, &walk);
+                memset(tweak, 0, AES_BLOCK_SIZE);
+                aes_p8_encrypt(iv, tweak, &ctx->tweak_key);
+
+                while ((nbytes = walk.nbytes)) {
+                        if (enc)
+                                aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
+                                                nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak);
+                        else
+                                aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
+                                                nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak);
+
+                        nbytes &= AES_BLOCK_SIZE - 1;
+                        ret = blkcipher_walk_done(desc, &walk, nbytes);
+                }
+
+                disable_kernel_vsx();
+                pagefault_enable();
+                preempt_enable();
+        }
+        return ret;
+}
+
+static int p8_aes_xts_encrypt(struct blkcipher_desc *desc,
+                              struct scatterlist *dst,
+                              struct scatterlist *src, unsigned int nbytes)
+{
+        return p8_aes_xts_crypt(desc, dst, src, nbytes, 1);
+}
+
+static int p8_aes_xts_decrypt(struct blkcipher_desc *desc,
+                              struct scatterlist *dst,
+                              struct scatterlist *src, unsigned int nbytes)
+{
+        return p8_aes_xts_crypt(desc, dst, src, nbytes, 0);
+}
+
+struct crypto_alg p8_aes_xts_alg = {
+        .cra_name = "xts(aes)",
+        .cra_driver_name = "p8_aes_xts",
+        .cra_module = THIS_MODULE,
+        .cra_priority = 2000,
+        .cra_type = &crypto_blkcipher_type,
+        .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
+        .cra_alignmask = 0,
+        .cra_blocksize = AES_BLOCK_SIZE,
+        .cra_ctxsize = sizeof(struct p8_aes_xts_ctx),
+        .cra_init = p8_aes_xts_init,
+        .cra_exit = p8_aes_xts_exit,
+        .cra_blkcipher = {
+                        .ivsize = AES_BLOCK_SIZE,
+                        .min_keysize = 2 * AES_MIN_KEY_SIZE,
+                        .max_keysize = 2 * AES_MAX_KEY_SIZE,
+                        .setkey  = p8_aes_xts_setkey,
+                        .encrypt = p8_aes_xts_encrypt,
+                        .decrypt = p8_aes_xts_decrypt,
+        }
+};
diff --git a/drivers/crypto/vmx/vmx.c b/drivers/crypto/vmx/vmx.c
index e163d5770438..f688c32fbcc7 100644
--- a/drivers/crypto/vmx/vmx.c
+++ b/drivers/crypto/vmx/vmx.c
@@ -31,10 +31,12 @@ extern struct shash_alg p8_ghash_alg;
 extern struct crypto_alg p8_aes_alg;
 extern struct crypto_alg p8_aes_cbc_alg;
 extern struct crypto_alg p8_aes_ctr_alg;
+extern struct crypto_alg p8_aes_xts_alg;
 static struct crypto_alg *algs[] = {
         &p8_aes_alg,
         &p8_aes_cbc_alg,
         &p8_aes_ctr_alg,
+        &p8_aes_xts_alg,
         NULL,
 };