cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sun8i-ce-trng.c (2929B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * sun8i-ce-trng.c - hardware cryptographic offloader for
      4 * Allwinner H3/A64/H5/H2+/H6/R40 SoC
      5 *
      6 * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
      7 *
      8 * This file handle the TRNG
      9 *
     10 * You could find a link for the datasheet in Documentation/arm/sunxi.rst
     11 */
     12#include "sun8i-ce.h"
     13#include <linux/dma-mapping.h>
     14#include <linux/pm_runtime.h>
     15#include <linux/hw_random.h>
     16/*
     17 * Note that according to the algorithm ID, 2 versions of the TRNG exists,
     18 * The first present in H3/H5/R40/A64 and the second present in H6.
     19 * This file adds support for both, but only the second is working
     20 * reliabily according to rngtest.
     21 **/
     22
     23static int sun8i_ce_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
     24{
     25	struct sun8i_ce_dev *ce;
     26	dma_addr_t dma_dst;
     27	int err = 0;
     28	int flow = 3;
     29	unsigned int todo;
     30	struct sun8i_ce_flow *chan;
     31	struct ce_task *cet;
     32	u32 common;
     33	void *d;
     34
     35	ce = container_of(rng, struct sun8i_ce_dev, trng);
     36
     37	/* round the data length to a multiple of 32*/
     38	todo = max + 32;
     39	todo -= todo % 32;
     40
     41	d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
     42	if (!d)
     43		return -ENOMEM;
     44
     45#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
     46	ce->hwrng_stat_req++;
     47	ce->hwrng_stat_bytes += todo;
     48#endif
     49
     50	dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
     51	if (dma_mapping_error(ce->dev, dma_dst)) {
     52		dev_err(ce->dev, "Cannot DMA MAP DST\n");
     53		err = -EFAULT;
     54		goto err_dst;
     55	}
     56
     57	err = pm_runtime_get_sync(ce->dev);
     58	if (err < 0) {
     59		pm_runtime_put_noidle(ce->dev);
     60		goto err_pm;
     61	}
     62
     63	mutex_lock(&ce->rnglock);
     64	chan = &ce->chanlist[flow];
     65
     66	cet = &chan->tl[0];
     67	memset(cet, 0, sizeof(struct ce_task));
     68
     69	cet->t_id = cpu_to_le32(flow);
     70	common = ce->variant->trng | CE_COMM_INT;
     71	cet->t_common_ctl = cpu_to_le32(common);
     72
     73	/* recent CE (H6) need length in bytes, in word otherwise */
     74	if (ce->variant->trng_t_dlen_in_bytes)
     75		cet->t_dlen = cpu_to_le32(todo);
     76	else
     77		cet->t_dlen = cpu_to_le32(todo / 4);
     78
     79	cet->t_sym_ctl = 0;
     80	cet->t_asym_ctl = 0;
     81
     82	cet->t_dst[0].addr = cpu_to_le32(dma_dst);
     83	cet->t_dst[0].len = cpu_to_le32(todo / 4);
     84	ce->chanlist[flow].timeout = todo;
     85
     86	err = sun8i_ce_run_task(ce, 3, "TRNG");
     87	mutex_unlock(&ce->rnglock);
     88
     89	pm_runtime_put(ce->dev);
     90
     91err_pm:
     92	dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
     93
     94	if (!err) {
     95		memcpy(data, d, max);
     96		err = max;
     97	}
     98err_dst:
     99	kfree_sensitive(d);
    100	return err;
    101}
    102
    103int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce)
    104{
    105	int ret;
    106
    107	if (ce->variant->trng == CE_ID_NOTSUPP) {
    108		dev_info(ce->dev, "TRNG not supported\n");
    109		return 0;
    110	}
    111	ce->trng.name = "sun8i Crypto Engine TRNG";
    112	ce->trng.read = sun8i_ce_trng_read;
    113	ce->trng.quality = 1000;
    114
    115	ret = hwrng_register(&ce->trng);
    116	if (ret)
    117		dev_err(ce->dev, "Fail to register the TRNG\n");
    118	return ret;
    119}
    120
    121void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce)
    122{
    123	if (ce->variant->trng == CE_ID_NOTSUPP)
    124		return;
    125	hwrng_unregister(&ce->trng);
    126}