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From:   Stephan Mueller <stephan.mueller@atsec.com>
To:     Corentin Labbe <clabbe@baylibre.com>
Cc:     davem@davemloft.net, herbert@gondor.apana.org.au,
        mripard@kernel.org, wens@csie.org,
        linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com
Subject: Re: [PATCH v2 14/14] crypto: sun8i-ce: Add support for the TRNG
Date:   Fri, 24 Apr 2020 16:34:40 +0200
Message-ID: <3693153.CBanSm0cUG@tauon.chronox.de>
Organization: atsec information security GmbH
In-Reply-To: <1587736934-22801-15-git-send-email-clabbe@baylibre.com>
References: <1587736934-22801-1-git-send-email-clabbe@baylibre.com> <1587736934-22801-15-git-send-email-clabbe@baylibre.com>
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Am Freitag, 24. April 2020, 16:02:14 CEST schrieb Corentin Labbe:

Hi Corentin,

> This patch had support for the TRNG present in the CE.
> Note that according to the algorithm ID, 2 version of the TRNG exists,
> the first present in H3/H5/R40/A64 and the second present in H6.
> This patch adds support for both, but only the second is working
> reliabily accoridng to rngtest.
> 
> Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
> ---
>  drivers/crypto/allwinner/Kconfig              |   8 ++
>  drivers/crypto/allwinner/sun8i-ce/Makefile    |   1 +
>  .../crypto/allwinner/sun8i-ce/sun8i-ce-core.c |  18 +++
>  .../crypto/allwinner/sun8i-ce/sun8i-ce-trng.c | 123 ++++++++++++++++++
>  drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h  |  18 +++
>  5 files changed, 168 insertions(+)
>  create mode 100644 drivers/crypto/allwinner/sun8i-ce/sun8i-ce-trng.c
> 
> diff --git a/drivers/crypto/allwinner/Kconfig
> b/drivers/crypto/allwinner/Kconfig index 223a5823867c..6aec31f7d2be 100644
> --- a/drivers/crypto/allwinner/Kconfig
> +++ b/drivers/crypto/allwinner/Kconfig
> @@ -87,6 +87,14 @@ config CRYPTO_DEV_SUN8I_CE_PRNG
>  	  Select this option if you want to provide kernel-side support for
>  	  the Pseudo-Random Number Generator found in the Crypto Engine.
> 
> +config CRYPTO_DEV_SUN8I_CE_TRNG
> +	bool "Support for Allwinner Crypto Engine TRNG"
> +	depends on CRYPTO_DEV_SUN8I_CE
> +	select HW_RANDOM
> +	help
> +	  Select this option if you want to provide kernel-side support for
> +	  the True Random Number Generator found in the Crypto Engine.
> +
>  config CRYPTO_DEV_SUN8I_SS
>  	tristate "Support for Allwinner Security System cryptographic 
offloader"
>  	select CRYPTO_SKCIPHER
> diff --git a/drivers/crypto/allwinner/sun8i-ce/Makefile
> b/drivers/crypto/allwinner/sun8i-ce/Makefile index
> c0ea81da2c7d..0842eb2d9408 100644
> --- a/drivers/crypto/allwinner/sun8i-ce/Makefile
> +++ b/drivers/crypto/allwinner/sun8i-ce/Makefile
> @@ -2,3 +2,4 @@ obj-$(CONFIG_CRYPTO_DEV_SUN8I_CE) += sun8i-ce.o
>  sun8i-ce-y += sun8i-ce-core.o sun8i-ce-cipher.o
>  sun8i-ce-$(CONFIG_CRYPTO_DEV_SUN8I_CE_HASH) += sun8i-ce-hash.o
>  sun8i-ce-$(CONFIG_CRYPTO_DEV_SUN8I_CE_PRNG) += sun8i-ce-prng.o
> +sun8i-ce-$(CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG) += sun8i-ce-trng.o
> diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
> b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c index
> 23b9fc67d7ea..86d75789811f 100644
> --- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
> +++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
> @@ -47,6 +47,7 @@ static const struct ce_variant ce_h3_variant = {
>  		},
>  	.esr = ESR_H3,
>  	.prng = CE_ALG_PRNG,
> +	.trng = CE_ID_NOTSUPP,
>  };
> 
>  static const struct ce_variant ce_h5_variant = {
> @@ -63,6 +64,7 @@ static const struct ce_variant ce_h5_variant = {
>  		},
>  	.esr = ESR_H5,
>  	.prng = CE_ALG_PRNG,
> +	.trng = CE_ID_NOTSUPP,
>  };
> 
>  static const struct ce_variant ce_h6_variant = {
> @@ -76,6 +78,7 @@ static const struct ce_variant ce_h6_variant = {
>  	.cipher_t_dlen_in_bytes = true,
>  	.hash_t_dlen_in_bits = true,
>  	.prng_t_dlen_in_bytes = true,
> +	.trng_t_dlen_in_bytes = true,
>  	.ce_clks = {
>  		{ "bus", 0, 200000000 },
>  		{ "mod", 300000000, 0 },
> @@ -83,6 +86,7 @@ static const struct ce_variant ce_h6_variant = {
>  		},
>  	.esr = ESR_H6,
>  	.prng = CE_ALG_PRNG_V2,
> +	.trng = CE_ALG_TRNG_V2,
>  };
> 
>  static const struct ce_variant ce_a64_variant = {
> @@ -99,6 +103,7 @@ static const struct ce_variant ce_a64_variant = {
>  		},
>  	.esr = ESR_A64,
>  	.prng = CE_ALG_PRNG,
> +	.trng = CE_ID_NOTSUPP,
>  };
> 
>  static const struct ce_variant ce_r40_variant = {
> @@ -115,6 +120,7 @@ static const struct ce_variant ce_r40_variant = {
>  		},
>  	.esr = ESR_R40,
>  	.prng = CE_ALG_PRNG,
> +	.trng = CE_ID_NOTSUPP,
>  };
> 
>  /*
> @@ -579,6 +585,10 @@ static int sun8i_ce_dbgfs_read(struct seq_file *seq,
> void *v) break;
>  		}
>  	}
> +#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG
> +	seq_printf(seq, "HWRNG %lu %lu\n",
> +		   ce->hwrng_stat_req, ce->hwrng_stat_bytes);
> +#endif
>  	return 0;
>  }
> 
> @@ -928,6 +938,10 @@ static int sun8i_ce_probe(struct platform_device *pdev)
> if (err < 0)
>  		goto error_alg;
> 
> +#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG
> +	sun8i_ce_hwrng_register(ce);
> +#endif
> +
>  	v = readl(ce->base + CE_CTR);
>  	v >>= CE_DIE_ID_SHIFT;
>  	v &= CE_DIE_ID_MASK;
> @@ -957,6 +971,10 @@ static int sun8i_ce_remove(struct platform_device
> *pdev) {
>  	struct sun8i_ce_dev *ce = platform_get_drvdata(pdev);
> 
> +#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG
> +	sun8i_ce_hwrng_unregister(ce);
> +#endif
> +
>  	sun8i_ce_unregister_algs(ce);
> 
>  #ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
> diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-trng.c
> b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-trng.c new file mode 100644
> index 000000000000..5e4effe29ed3
> --- /dev/null
> +++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-trng.c
> @@ -0,0 +1,123 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * sun8i-ce-trng.c - hardware cryptographic offloader for
> + * Allwinner H3/A64/H5/H2+/H6/R40 SoC
> + *
> + * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
> + *
> + * This file handle the TRNG
> + *
> + * You could find a link for the datasheet in
> Documentation/arm/sunxi/README + */
> +#include "sun8i-ce.h"
> +#include <linux/pm_runtime.h>
> +#include <linux/hw_random.h>
> +/*
> + * Note that according to the algorithm ID, 2 versions of the TRNG exists,
> + * The first present in H3/H5/R40/A64 and the second present in H6.
> + * This file adds support for both, but only the second is working
> + * reliabily according to rngtest.
> + **/
> +
> +int sun8i_ce_trng_read(struct hwrng *rng, void *data, size_t max, bool
> wait) +{
> +	struct sun8i_ce_dev *ce;
> +	dma_addr_t dma_dst;
> +	int err = 0;
> +	int flow = 3;
> +	unsigned int todo;
> +	struct sun8i_ce_flow *chan;
> +	struct ce_task *cet;
> +	u32 common;
> +	void *d;
> +
> +	ce = container_of(rng, struct sun8i_ce_dev, trng);
> +
> +	todo = max + 32;
> +	todo -= todo % 32;
> +
> +	d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
> +	if (!d)
> +		return -ENOMEM;
> +
> +#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
> +	ce->hwrng_stat_req++;
> +	ce->hwrng_stat_bytes += todo;
> +#endif
> +
> +	dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
> +	if (dma_mapping_error(ce->dev, dma_dst)) {
> +		dev_err(ce->dev, "Cannot DMA MAP DST\n");
> +		err = -EFAULT;
> +		goto err_dst;
> +	}
> +
> +	err = pm_runtime_get_sync(ce->dev);
> +	if (err < 0)
> +		goto err_pm;
> +
> +	mutex_lock(&ce->rnglock);
> +	chan = &ce->chanlist[flow];
> +
> +	cet = &chan->tl[0];
> +	memset(cet, 0, sizeof(struct ce_task));
> +
> +	cet->t_id = cpu_to_le32(flow);
> +	common = ce->variant->trng | CE_COMM_INT;
> +	cet->t_common_ctl = cpu_to_le32(common);
> +
> +	/* recent CE (H6) need length in bytes, in word otherwise */
> +	if (ce->variant->trng_t_dlen_in_bytes)
> +		cet->t_dlen = cpu_to_le32(todo);
> +	else
> +		cet->t_dlen = cpu_to_le32(todo / 4);
> +
> +	cet->t_sym_ctl = 0;
> +	cet->t_asym_ctl = 0;
> +
> +	cet->t_dst[0].addr = cpu_to_le32(dma_dst);
> +	cet->t_dst[0].len = cpu_to_le32(todo / 4);
> +	ce->chanlist[flow].timeout = 2000;
> +
> +	err = sun8i_ce_run_task(ce, 3, "TRNG");
> +	mutex_unlock(&ce->rnglock);
> +
> +	pm_runtime_put(ce->dev);
> +
> +err_pm:
> +	dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
> +
> +	if (!err) {
> +		memcpy(data, d, max);
> +		err = max;
> +	}
> +
> +err_dst:
> +	kfree(d);

kzfree? I would assume d contains sensitive data, no?

> +	return err;
> +}
> +
> +int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce)
> +{
> +	int ret;
> +
> +	if (ce->variant->trng == CE_ID_NOTSUPP) {
> +		dev_info(ce->dev, "TRNG not supported\n");
> +		return 0;
> +	}
> +	ce->trng.name = "sun8i Crypto Engine TRNG";
> +	ce->trng.read = sun8i_ce_trng_read;
> +	ce->trng.quality = 1000;
> +
> +	ret = hwrng_register(&ce->trng);
> +	if (ret)
> +		dev_err(ce->dev, "Fail to register the TRNG\n");
> +	return ret;
> +}
> +
> +void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce)
> +{
> +	if (ce->variant->trng == CE_ID_NOTSUPP)
> +		return;
> +	hwrng_unregister(&ce->trng);
> +}
> diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
> b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h index
> 2ef0c3814367..746e56c254d4 100644
> --- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
> +++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
> @@ -12,6 +12,7 @@
>  #include <linux/atomic.h>
>  #include <linux/debugfs.h>
>  #include <linux/crypto.h>
> +#include <linux/hw_random.h>
>  #include <crypto/internal/hash.h>
>  #include <crypto/md5.h>
>  #include <crypto/rng.h>
> @@ -55,7 +56,9 @@
>  #define CE_ALG_SHA256           19
>  #define CE_ALG_SHA384           20
>  #define CE_ALG_SHA512           21
> +#define CE_ALG_TRNG		48
>  #define CE_ALG_PRNG		49
> +#define CE_ALG_TRNG_V2		0x1c
>  #define CE_ALG_PRNG_V2		0x1d
> 
>  /* Used in ce_variant */
> @@ -129,9 +132,12 @@ struct ce_clock {
>   *				bits or words
>   * @prng_t_dlen_in_bytes:	Does the request size for PRNG is in
>   *				bytes or words
> + * @trng_t_dlen_in_bytes:	Does the request size for TRNG is in
> + *				bytes or words
>   * @ce_clks:	list of clocks needed by this variant
>   * @esr:	The type of error register
>   * @prng:	The CE_ALG_XXX value for the PRNG
> + * @trng:	The CE_ALG_XXX value for the TRNG
>   */
>  struct ce_variant {
>  	char alg_cipher[CE_ID_CIPHER_MAX];
> @@ -140,9 +146,11 @@ struct ce_variant {
>  	bool cipher_t_dlen_in_bytes;
>  	bool hash_t_dlen_in_bits;
>  	bool prng_t_dlen_in_bytes;
> +	bool trng_t_dlen_in_bytes;
>  	struct ce_clock ce_clks[CE_MAX_CLOCKS];
>  	int esr;
>  	char prng;
> +	char trng;
>  };
> 
>  struct sginfo {
> @@ -218,6 +226,13 @@ struct sun8i_ce_dev {
>  	struct dentry *dbgfs_dir;
>  	struct dentry *dbgfs_stats;
>  #endif
> +#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG
> +	struct hwrng trng;
> +#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
> +	unsigned long hwrng_stat_req;
> +	unsigned long hwrng_stat_bytes;
> +#endif
> +#endif
>  };
> 
>  /*
> @@ -349,3 +364,6 @@ int sun8i_ce_prng_generate(struct crypto_rng *tfm, const
> u8 *src, int sun8i_ce_prng_seed(struct crypto_rng *tfm, const u8 *seed,
> unsigned int slen); void sun8i_ce_prng_exit(struct crypto_tfm *tfm);
>  int sun8i_ce_prng_init(struct crypto_tfm *tfm);
> +
> +int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce);
> +void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce);


Ciao
Stephan
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