Re: [PATCH V2 4/4] crypto: Add Xilinx AES driver

Corentin Labbe
2019-09-02T06:59:03Z

On Sun, Sep 01, 2019 at 07:24:58PM +0530, Kalyani Akula wrote:
> This patch adds AES driver support for the Xilinx
> ZynqMP SoC.
>
> Signed-off-by: Kalyani Akula <kalyani.akula@xilinx.com>
> ---

Hello

I have some comment below

> drivers/crypto/Kconfig | 11 ++
> drivers/crypto/Makefile | 1 +
> drivers/crypto/zynqmp-aes-gcm.c | 297 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 309 insertions(+)
> create mode 100644 drivers/crypto/zynqmp-aes-gcm.c
>
> diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
> index 603413f..a0d058a 100644
> --- a/drivers/crypto/Kconfig
> +++ b/drivers/crypto/Kconfig
> @@ -677,6 +677,17 @@ config CRYPTO_DEV_ROCKCHIP
> This driver interfaces with the hardware crypto accelerator.
> Supporting cbc/ecb chainmode, and aes/des/des3_ede cipher mode.
>
> +config CRYPTO_DEV_ZYNQMP_AES
> + tristate "Support for Xilinx ZynqMP AES hw accelerator"
> + depends on ARCH_ZYNQMP || COMPILE_TEST
> + select CRYPTO_AES
> + select CRYPTO_SKCIPHER
> + help
> + Xilinx ZynqMP has AES-GCM engine used for symmetric key
> + encryption and decryption. This driver interfaces with AES hw
> + accelerator. Select this if you want to use the ZynqMP module
> + for AES algorithms.
> +
> config CRYPTO_DEV_MEDIATEK
> tristate "MediaTek's EIP97 Cryptographic Engine driver"
> depends on (ARM && ARCH_MEDIATEK) || COMPILE_TEST
> diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile
> index afc4753..c99663a 100644
> --- a/drivers/crypto/Makefile
> +++ b/drivers/crypto/Makefile
> @@ -48,3 +48,4 @@ obj-$(CONFIG_CRYPTO_DEV_BCM_SPU) += bcm/
> obj-$(CONFIG_CRYPTO_DEV_SAFEXCEL) += inside-secure/
> obj-$(CONFIG_CRYPTO_DEV_ARTPEC6) += axis/
> obj-y += hisilicon/
> +obj-$(CONFIG_CRYPTO_DEV_ZYNQMP_AES) += zynqmp-aes-gcm.o
> diff --git a/drivers/crypto/zynqmp-aes-gcm.c b/drivers/crypto/zynqmp-aes-gcm.c
> new file mode 100644
> index 0000000..d65f038
> --- /dev/null
> +++ b/drivers/crypto/zynqmp-aes-gcm.c
> @@ -0,0 +1,297 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Xilinx ZynqMP AES Driver.
> + * Copyright (c) 2019 Xilinx Inc.
> + */
> +
> +#include <crypto/aes.h>
> +#include <crypto/scatterwalk.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/scatterlist.h>
> +#include <linux/firmware/xlnx-zynqmp.h>
> +
> +#define ZYNQMP_AES_IV_SIZE 12
> +#define ZYNQMP_AES_GCM_SIZE 16
> +#define ZYNQMP_AES_KEY_SIZE 32
> +
> +#define ZYNQMP_AES_DECRYPT 0
> +#define ZYNQMP_AES_ENCRYPT 1
> +
> +#define ZYNQMP_AES_KUP_KEY 0
> +#define ZYNQMP_AES_DEVICE_KEY 1
> +#define ZYNQMP_AES_PUF_KEY 2
> +
> +#define ZYNQMP_AES_GCM_TAG_MISMATCH_ERR 0x01
> +#define ZYNQMP_AES_SIZE_ERR 0x06
> +#define ZYNQMP_AES_WRONG_KEY_SRC_ERR 0x13
> +#define ZYNQMP_AES_PUF_NOT_PROGRAMMED 0xE300
> +
> +#define ZYNQMP_AES_BLOCKSIZE 0x04
> +
> +static const struct zynqmp_eemi_ops *eemi_ops;
> +struct zynqmp_aes_dev *aes_dd;

I still think that using a global variable for storing device driver data is bad.

> +
> +struct zynqmp_aes_dev {
> + struct device *dev;
> +};
> +
> +struct zynqmp_aes_op {
> + struct zynqmp_aes_dev *dd;
> + void *src;
> + void *dst;
> + int len;
> + u8 key[ZYNQMP_AES_KEY_SIZE];
> + u8 *iv;
> + u32 keylen;
> + u32 keytype;
> +};
> +
> +struct zynqmp_aes_data {
> + u64 src;
> + u64 iv;
> + u64 key;
> + u64 dst;
> + u64 size;
> + u64 optype;
> + u64 keysrc;
> +};
> +
> +static int zynqmp_setkey_blk(struct crypto_tfm *tfm, const u8 *key,
> + unsigned int len)
> +{
> + struct zynqmp_aes_op *op = crypto_tfm_ctx(tfm);
> +
> + if (((len != 1) && (len != ZYNQMP_AES_KEY_SIZE)) || (!key))

typo, two space

> + return -EINVAL;
> +
> + if (len == 1) {
> + op->keytype = *key;
> +
> + if ((op->keytype < ZYNQMP_AES_KUP_KEY) ||
> + (op->keytype > ZYNQMP_AES_PUF_KEY))
> + return -EINVAL;
> +
> + } else if (len == ZYNQMP_AES_KEY_SIZE) {
> + op->keytype = ZYNQMP_AES_KUP_KEY;
> + op->keylen = len;
> + memcpy(op->key, key, len);
> + }
> +
> + return 0;
> +}

It seems your driver does not support AES keysize of 128/196, you need to fallback in that case.
You need to comment the keylen=1 usecase and use a define for this value.

> +
> +static int zynqmp_aes_xcrypt(struct blkcipher_desc *desc,
> + struct scatterlist *dst,
> + struct scatterlist *src,
> + unsigned int nbytes,
> + unsigned int flags)
> +{
> + struct zynqmp_aes_op *op = crypto_blkcipher_ctx(desc->tfm);
> + struct zynqmp_aes_dev *dd = aes_dd;
> + int err, ret, copy_bytes, src_data = 0, dst_data = 0;
> + dma_addr_t dma_addr, dma_addr_buf;
> + struct zynqmp_aes_data *abuf;
> + struct blkcipher_walk walk;
> + unsigned int data_size;
> + size_t dma_size;
> + char *kbuf;
> +
> + if (!eemi_ops->aes)
> + return -ENOTSUPP;
> +
> + if (op->keytype == ZYNQMP_AES_KUP_KEY)
> + dma_size = nbytes + ZYNQMP_AES_KEY_SIZE
> + + ZYNQMP_AES_IV_SIZE;
> + else
> + dma_size = nbytes + ZYNQMP_AES_IV_SIZE;
> +
> + kbuf = dma_alloc_coherent(dd->dev, dma_size, &dma_addr, GFP_KERNEL);
> + if (!kbuf)
> + return -ENOMEM;
> +
> + abuf = dma_alloc_coherent(dd->dev, sizeof(struct zynqmp_aes_data),
> + &dma_addr_buf, GFP_KERNEL);
> + if (!abuf) {
> + dma_free_coherent(dd->dev, dma_size, kbuf, dma_addr);
> + return -ENOMEM;
> + }
> +
> + data_size = nbytes;
> + blkcipher_walk_init(&walk, dst, src, data_size);
> + err = blkcipher_walk_virt(desc, &walk);
> + op->iv = walk.iv;
> +
> + while ((nbytes = walk.nbytes)) {
> + op->src = walk.src.virt.addr;
> + memcpy(kbuf + src_data, op->src, nbytes);
> + src_data = src_data + nbytes;
> + nbytes &= (ZYNQMP_AES_BLOCKSIZE - 1);
> + err = blkcipher_walk_done(desc, &walk, nbytes);
> + }
> + memcpy(kbuf + data_size, op->iv, ZYNQMP_AES_IV_SIZE);
> + abuf->src = dma_addr;
> + abuf->dst = dma_addr;
> + abuf->iv = abuf->src + data_size;
> + abuf->size = data_size - ZYNQMP_AES_GCM_SIZE;
> + abuf->optype = flags;
> + abuf->keysrc = op->keytype;
> +
> + if (op->keytype == ZYNQMP_AES_KUP_KEY) {
> + memcpy(kbuf + data_size + ZYNQMP_AES_IV_SIZE,
> + op->key, ZYNQMP_AES_KEY_SIZE);
> +
> + abuf->key = abuf->src + data_size + ZYNQMP_AES_IV_SIZE;
> + } else {
> + abuf->key = 0;
> + }
> + eemi_ops->aes(dma_addr_buf, &ret);
> +
> + if (ret != 0) {
> + switch (ret) {
> + case ZYNQMP_AES_GCM_TAG_MISMATCH_ERR:
> + dev_err(dd->dev, "ERROR: Gcm Tag mismatch\n\r");
> + break;
> + case ZYNQMP_AES_SIZE_ERR:
> + dev_err(dd->dev, "ERROR : Non word aligned data\n\r");
> + break;
> + case ZYNQMP_AES_WRONG_KEY_SRC_ERR:
> + dev_err(dd->dev, "ERROR: Wrong KeySrc, enable secure mode\n\r");
> + break;
> + case ZYNQMP_AES_PUF_NOT_PROGRAMMED:
> + dev_err(dd->dev, "ERROR: PUF is not registered\r\n");
> + break;
> + default:
> + dev_err(dd->dev, "ERROR: Invalid");
> + break;
> + }
> + goto END;
> + }
> + if (flags)
> + copy_bytes = data_size;
> + else
> + copy_bytes = data_size - ZYNQMP_AES_GCM_SIZE;
> +
> + blkcipher_walk_init(&walk, dst, src, copy_bytes);
> + err = blkcipher_walk_virt(desc, &walk);
> +
> + while ((nbytes = walk.nbytes)) {
> + memcpy(walk.dst.virt.addr, kbuf + dst_data, nbytes);
> + dst_data = dst_data + nbytes;
> + nbytes &= (ZYNQMP_AES_BLOCKSIZE - 1);
> + err = blkcipher_walk_done(desc, &walk, nbytes);
> + }
> +END:
> + memset(kbuf, 0, dma_size);
> + memset(abuf, 0, sizeof(struct zynqmp_aes_data));
> + dma_free_coherent(dd->dev, dma_size, kbuf, dma_addr);
> + dma_free_coherent(dd->dev, sizeof(struct zynqmp_aes_data),
> + abuf, dma_addr_buf);
> + return err;
> +}
> +
> +static int zynqmp_aes_decrypt(struct blkcipher_desc *desc,
> + struct scatterlist *dst,
> + struct scatterlist *src,
> + unsigned int nbytes)
> +{
> + return zynqmp_aes_xcrypt(desc, dst, src, nbytes, ZYNQMP_AES_DECRYPT);
> +}
> +
> +static int zynqmp_aes_encrypt(struct blkcipher_desc *desc,
> + struct scatterlist *dst,
> + struct scatterlist *src,
> + unsigned int nbytes)
> +{
> + return zynqmp_aes_xcrypt(desc, dst, src, nbytes, ZYNQMP_AES_ENCRYPT);
> +}
> +
> +static struct crypto_alg zynqmp_alg = {
> + .cra_name = "xilinx-zynqmp-aes",
> + .cra_driver_name = "zynqmp-aes-gcm",
> + .cra_priority = 400,
> + .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER |
> + CRYPTO_ALG_KERN_DRIVER_ONLY,
> + .cra_blocksize = ZYNQMP_AES_BLOCKSIZE,
> + .cra_ctxsize = sizeof(struct zynqmp_aes_op),
> + .cra_alignmask = 15,
> + .cra_type = &crypto_blkcipher_type,
> + .cra_module = THIS_MODULE,
> + .cra_u = {
> + .blkcipher = {
> + .min_keysize = 0,

Are you sure to accept this a keysize of 0 ?

Regards