This patch adds AES CTR routines to VMX module in order to
make use of VMX cryptographic acceleration instructions
on Power 8 CPU.
Signed-off-by: Leonidas S. Barbosa <leosilva@xxxxxxxxxxxxxxxxxx>
---
drivers/crypto/vmx/aes_ctr.c | 167 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 167 insertions(+)
create mode 100644 drivers/crypto/vmx/aes_ctr.c
diff --git a/drivers/crypto/vmx/aes_ctr.c b/drivers/crypto/vmx/aes_ctr.c
new file mode 100644
index 0000000..96dbee4
--- /dev/null
+++ b/drivers/crypto/vmx/aes_ctr.c
@@ -0,0 +1,167 @@
+/**
+ * AES CTR routines supporting VMX instructions on the 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 Foundation; 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 or FITNESS FOR A PARTICULAR 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: Marcelo Henrique Cerri <mhcerri@xxxxxxxxxx>
+ */
+
+#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 "aesp8-ppc.h"
+
+struct p8_aes_ctr_ctx {
+ struct crypto_blkcipher *fallback;
+ struct aes_key enc_key;
+};
+
+static int p8_aes_ctr_init(struct crypto_tfm *tfm)
+{
+ const char *alg;
+ struct crypto_blkcipher *fallback;
+ struct p8_aes_ctr_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_ctr_exit(struct crypto_tfm *tfm)
+{
+ struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ if (ctx->fallback) {
+ crypto_free_blkcipher(ctx->fallback);
+ ctx->fallback = NULL;
+ }
+}
+
+static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key,
+ unsigned int keylen)
+{
+ int ret;
+ struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ pagefault_disable();
+ enable_kernel_altivec();
+ ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
+ pagefault_enable();
+
+ ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen);
+ return ret;
+}
+
+static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx,
+ struct blkcipher_walk *walk)
+{
+ u8 *ctrblk = walk->iv;
+ u8 keystream[AES_BLOCK_SIZE];
+ u8 *src = walk->src.virt.addr;
+ u8 *dst = walk->dst.virt.addr;
+ unsigned int nbytes = walk->nbytes;
+
+ pagefault_disable();
+ enable_kernel_altivec();
+ aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
+ pagefault_enable();
+
+ crypto_xor(keystream, src, nbytes);
+ memcpy(dst, keystream, nbytes);
+ crypto_inc(ctrblk, AES_BLOCK_SIZE);
+}
+
+static int p8_aes_ctr_crypt(struct blkcipher_desc *desc,
+ struct scatterlist *dst, struct scatterlist *src,
+ unsigned int nbytes)
+{
+ int ret;
+ struct blkcipher_walk walk;
+ struct p8_aes_ctr_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 = crypto_blkcipher_encrypt(&fallback_desc, dst, src, nbytes);
+ } else {
+ blkcipher_walk_init(&walk, dst, src, nbytes);
+ ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
+ while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
+ pagefault_disable();
+ enable_kernel_altivec();
+ aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr, walk.dst.virt.addr,
+ (nbytes & AES_BLOCK_MASK)/AES_BLOCK_SIZE, &ctx->enc_key, walk.iv);
+ pagefault_enable();
+
+ crypto_inc(walk.iv, AES_BLOCK_SIZE);
+ nbytes &= AES_BLOCK_SIZE - 1;
+ ret = blkcipher_walk_done(desc, &walk, nbytes);
+ }
+ if (walk.nbytes) {
+ p8_aes_ctr_final(ctx, &walk);
+ ret = blkcipher_walk_done(desc, &walk, 0);
+ }
+ }
+
+ return ret;
+}
+
+struct crypto_alg p8_aes_ctr_alg = {
+ .cra_name = "ctr(aes)",
+ .cra_driver_name = "p8_aes_ctr",
+ .cra_module = THIS_MODULE,
+ .cra_priority = 1000,
+ .cra_type = &crypto_blkcipher_type,
+ .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
+ .cra_alignmask = 0,
+ .cra_blocksize = 1,
+ .cra_ctxsize = sizeof(struct p8_aes_ctr_ctx),
+ .cra_init = p8_aes_ctr_init,
+ .cra_exit = p8_aes_ctr_exit,
+ .cra_blkcipher = {
+ .ivsize = 0,
+ .min_keysize = AES_MIN_KEY_SIZE,
+ .max_keysize = AES_MAX_KEY_SIZE,
+ .setkey = p8_aes_ctr_setkey,
+ .encrypt = p8_aes_ctr_crypt,
+ .decrypt = p8_aes_ctr_crypt,
+ },
+};
--
2.1.0
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