drivers/crypto/ccree/cc_ivgen.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2012-2018 ARM Limited or its affiliates. */
   3
   4 #include <crypto/ctr.h>
   5 #include "cc_driver.h"
   6 #include "cc_ivgen.h"
   7 #include "cc_request_mgr.h"
   8 #include "cc_sram_mgr.h"
   9 #include "cc_buffer_mgr.h"
  10
  11 /* The max. size of pool *MUST* be <= SRAM total size */
  12 #define CC_IVPOOL_SIZE 1024
  13 /* The first 32B fraction of pool are dedicated to the
  14  * next encryption "key" & "IV" for pool regeneration
  15  */
  16 #define CC_IVPOOL_META_SIZE (CC_AES_IV_SIZE + AES_KEYSIZE_128)
  17 #define CC_IVPOOL_GEN_SEQ_LEN   4
  18
  19 /**
  20  * struct cc_ivgen_ctx -IV pool generation context
  21  * @pool:          the start address of the iv-pool resides in internal RAM
  22  * @ctr_key_dma:   address of pool's encryption key material in internal RAM
  23  * @ctr_iv_dma:    address of pool's counter iv in internal RAM
  24  * @next_iv_ofs:   the offset to the next available IV in pool
  25  * @pool_meta:     virt. address of the initial enc. key/IV
  26  * @pool_meta_dma: phys. address of the initial enc. key/IV
  27  */
  28 struct cc_ivgen_ctx {
  29         cc_sram_addr_t pool;
  30         cc_sram_addr_t ctr_key;
  31         cc_sram_addr_t ctr_iv;
  32         u32 next_iv_ofs;
  33         u8 *pool_meta;
  34         dma_addr_t pool_meta_dma;
  35 };
  36
  37 /*!
  38  * Generates CC_IVPOOL_SIZE of random bytes by
  39  * encrypting 0's using AES128-CTR.
  40  *
  41  * \param ivgen iv-pool context
  42  * \param iv_seq IN/OUT array to the descriptors sequence
  43  * \param iv_seq_len IN/OUT pointer to the sequence length
  44  */
  45 static int cc_gen_iv_pool(struct cc_ivgen_ctx *ivgen_ctx,
  46                           struct cc_hw_desc iv_seq[], unsigned int *iv_seq_len)
  47 {
  48         unsigned int idx = *iv_seq_len;
  49
  50         if ((*iv_seq_len + CC_IVPOOL_GEN_SEQ_LEN) > CC_IVPOOL_SEQ_LEN) {
  51                 /* The sequence will be longer than allowed */
  52                 return -EINVAL;
  53         }
  54         /* Setup key */
  55         hw_desc_init(&iv_seq[idx]);
  56         set_din_sram(&iv_seq[idx], ivgen_ctx->ctr_key, AES_KEYSIZE_128);
  57         set_setup_mode(&iv_seq[idx], SETUP_LOAD_KEY0);
  58         set_cipher_config0(&iv_seq[idx], DESC_DIRECTION_ENCRYPT_ENCRYPT);
  59         set_flow_mode(&iv_seq[idx], S_DIN_to_AES);
  60         set_key_size_aes(&iv_seq[idx], CC_AES_128_BIT_KEY_SIZE);
  61         set_cipher_mode(&iv_seq[idx], DRV_CIPHER_CTR);
  62         idx++;
  63
  64         /* Setup cipher state */
  65         hw_desc_init(&iv_seq[idx]);
  66         set_din_sram(&iv_seq[idx], ivgen_ctx->ctr_iv, CC_AES_IV_SIZE);
  67         set_cipher_config0(&iv_seq[idx], DESC_DIRECTION_ENCRYPT_ENCRYPT);
  68         set_flow_mode(&iv_seq[idx], S_DIN_to_AES);
  69         set_setup_mode(&iv_seq[idx], SETUP_LOAD_STATE1);
  70         set_key_size_aes(&iv_seq[idx], CC_AES_128_BIT_KEY_SIZE);
  71         set_cipher_mode(&iv_seq[idx], DRV_CIPHER_CTR);
  72         idx++;
  73
  74         /* Perform dummy encrypt to skip first block */
  75         hw_desc_init(&iv_seq[idx]);
  76         set_din_const(&iv_seq[idx], 0, CC_AES_IV_SIZE);
  77         set_dout_sram(&iv_seq[idx], ivgen_ctx->pool, CC_AES_IV_SIZE);
  78         set_flow_mode(&iv_seq[idx], DIN_AES_DOUT);
  79         idx++;
  80
  81         /* Generate IV pool */
  82         hw_desc_init(&iv_seq[idx]);
  83         set_din_const(&iv_seq[idx], 0, CC_IVPOOL_SIZE);
  84         set_dout_sram(&iv_seq[idx], ivgen_ctx->pool, CC_IVPOOL_SIZE);
  85         set_flow_mode(&iv_seq[idx], DIN_AES_DOUT);
  86         idx++;
  87
  88         *iv_seq_len = idx; /* Update sequence length */
  89
  90         /* queue ordering assures pool readiness */
  91         ivgen_ctx->next_iv_ofs = CC_IVPOOL_META_SIZE;
  92
  93         return 0;
  94 }
  95
  96 /*!
  97  * Generates the initial pool in SRAM.
  98  * This function should be invoked when resuming driver.
  99  *
 100  * \param drvdata
 101  *
 102  * \return int Zero for success, negative value otherwise.
 103  */
 104 int cc_init_iv_sram(struct cc_drvdata *drvdata)
 105 {
 106         struct cc_ivgen_ctx *ivgen_ctx = drvdata->ivgen_handle;
 107         struct cc_hw_desc iv_seq[CC_IVPOOL_SEQ_LEN];
 108         unsigned int iv_seq_len = 0;
 109         int rc;
 110
 111         /* Generate initial enc. key/iv */
 112         get_random_bytes(ivgen_ctx->pool_meta, CC_IVPOOL_META_SIZE);
 113
 114         /* The first 32B reserved for the enc. Key/IV */
 115         ivgen_ctx->ctr_key = ivgen_ctx->pool;
 116         ivgen_ctx->ctr_iv = ivgen_ctx->pool + AES_KEYSIZE_128;
 117
 118         /* Copy initial enc. key and IV to SRAM at a single descriptor */
 119         hw_desc_init(&iv_seq[iv_seq_len]);
 120         set_din_type(&iv_seq[iv_seq_len], DMA_DLLI, ivgen_ctx->pool_meta_dma,
 121                      CC_IVPOOL_META_SIZE, NS_BIT);
 122         set_dout_sram(&iv_seq[iv_seq_len], ivgen_ctx->pool,
 123                       CC_IVPOOL_META_SIZE);
 124         set_flow_mode(&iv_seq[iv_seq_len], BYPASS);
 125         iv_seq_len++;
 126
 127         /* Generate initial pool */
 128         rc = cc_gen_iv_pool(ivgen_ctx, iv_seq, &iv_seq_len);
 129         if (rc)
 130                 return rc;
 131
 132         /* Fire-and-forget */
 133         return send_request_init(drvdata, iv_seq, iv_seq_len);
 134 }
 135
 136 /*!
 137  * Free iv-pool and ivgen context.
 138  *
 139  * \param drvdata
 140  */
 141 void cc_ivgen_fini(struct cc_drvdata *drvdata)
 142 {
 143         struct cc_ivgen_ctx *ivgen_ctx = drvdata->ivgen_handle;
 144         struct device *device = &drvdata->plat_dev->dev;
 145
 146         if (!ivgen_ctx)
 147                 return;
 148
 149         if (ivgen_ctx->pool_meta) {
 150                 memset(ivgen_ctx->pool_meta, 0, CC_IVPOOL_META_SIZE);
 151                 dma_free_coherent(device, CC_IVPOOL_META_SIZE,
 152                                   ivgen_ctx->pool_meta,
 153                                   ivgen_ctx->pool_meta_dma);
 154         }
 155
 156         ivgen_ctx->pool = NULL_SRAM_ADDR;
 157 }
 158
 159 /*!
 160  * Allocates iv-pool and maps resources.
 161  * This function generates the first IV pool.
 162  *
 163  * \param drvdata Driver's private context
 164  *
 165  * \return int Zero for success, negative value otherwise.
 166  */
 167 int cc_ivgen_init(struct cc_drvdata *drvdata)
 168 {
 169         struct cc_ivgen_ctx *ivgen_ctx;
 170         struct device *device = &drvdata->plat_dev->dev;
 171         int rc;
 172
 173         /* Allocate "this" context */
 174         ivgen_ctx = devm_kzalloc(device, sizeof(*ivgen_ctx), GFP_KERNEL);
 175         if (!ivgen_ctx)
 176                 return -ENOMEM;
 177
 178         drvdata->ivgen_handle = ivgen_ctx;
 179
 180         /* Allocate pool's header for initial enc. key/IV */
 181         ivgen_ctx->pool_meta = dma_alloc_coherent(device, CC_IVPOOL_META_SIZE,
 182                                                   &ivgen_ctx->pool_meta_dma,
 183                                                   GFP_KERNEL);
 184         if (!ivgen_ctx->pool_meta) {
 185                 dev_err(device, "Not enough memory to allocate DMA of pool_meta (%u B)\n",
 186                         CC_IVPOOL_META_SIZE);
 187                 rc = -ENOMEM;
 188                 goto out;
 189         }
 190         /* Allocate IV pool in SRAM */
 191         ivgen_ctx->pool = cc_sram_alloc(drvdata, CC_IVPOOL_SIZE);
 192         if (ivgen_ctx->pool == NULL_SRAM_ADDR) {
 193                 dev_err(device, "SRAM pool exhausted\n");
 194                 rc = -ENOMEM;
 195                 goto out;
 196         }
 197
 198         return cc_init_iv_sram(drvdata);
 199
 200 out:
 201         cc_ivgen_fini(drvdata);
 202         return rc;
 203 }
 204
 205 /*!
 206  * Acquires 16 Bytes IV from the iv-pool
 207  *
 208  * \param drvdata Driver private context
 209  * \param iv_out_dma Array of physical IV out addresses
 210  * \param iv_out_dma_len Length of iv_out_dma array (additional elements
 211  *                       of iv_out_dma array are ignore)
 212  * \param iv_out_size May be 8 or 16 bytes long
 213  * \param iv_seq IN/OUT array to the descriptors sequence
 214  * \param iv_seq_len IN/OUT pointer to the sequence length
 215  *
 216  * \return int Zero for success, negative value otherwise.
 217  */
 218 int cc_get_iv(struct cc_drvdata *drvdata, dma_addr_t iv_out_dma[],
 219               unsigned int iv_out_dma_len, unsigned int iv_out_size,
 220               struct cc_hw_desc iv_seq[], unsigned int *iv_seq_len)
 221 {
 222         struct cc_ivgen_ctx *ivgen_ctx = drvdata->ivgen_handle;
 223         unsigned int idx = *iv_seq_len;
 224         struct device *dev = drvdata_to_dev(drvdata);
 225         unsigned int t;
 226
 227         if (iv_out_size != CC_AES_IV_SIZE &&
 228             iv_out_size != CTR_RFC3686_IV_SIZE) {
 229                 return -EINVAL;
 230         }
 231         if ((iv_out_dma_len + 1) > CC_IVPOOL_SEQ_LEN) {
 232                 /* The sequence will be longer than allowed */
 233                 return -EINVAL;
 234         }
 235
 236         /* check that number of generated IV is limited to max dma address
 237          * iv buffer size
 238          */
 239         if (iv_out_dma_len > CC_MAX_IVGEN_DMA_ADDRESSES) {
 240                 /* The sequence will be longer than allowed */
 241                 return -EINVAL;
 242         }
 243
 244         for (t = 0; t < iv_out_dma_len; t++) {
 245                 /* Acquire IV from pool */
 246                 hw_desc_init(&iv_seq[idx]);
 247                 set_din_sram(&iv_seq[idx], (ivgen_ctx->pool +
 248                                             ivgen_ctx->next_iv_ofs),
 249                              iv_out_size);
 250                 set_dout_dlli(&iv_seq[idx], iv_out_dma[t], iv_out_size,
 251                               NS_BIT, 0);
 252                 set_flow_mode(&iv_seq[idx], BYPASS);
 253                 idx++;
 254         }
 255
 256         /* Bypass operation is proceeded by crypto sequence, hence must
 257          *  assure bypass-write-transaction by a memory barrier
 258          */
 259         hw_desc_init(&iv_seq[idx]);
 260         set_din_no_dma(&iv_seq[idx], 0, 0xfffff0);
 261         set_dout_no_dma(&iv_seq[idx], 0, 0, 1);
 262         idx++;
 263
 264         *iv_seq_len = idx; /* update seq length */
 265
 266         /* Update iv index */
 267         ivgen_ctx->next_iv_ofs += iv_out_size;
 268
 269         if ((CC_IVPOOL_SIZE - ivgen_ctx->next_iv_ofs) < CC_AES_IV_SIZE) {
 270                 dev_dbg(dev, "Pool exhausted, regenerating iv-pool\n");
 271                 /* pool is drained -regenerate it! */
 272                 return cc_gen_iv_pool(ivgen_ctx, iv_seq, iv_seq_len);
 273         }
 274
 275         return 0;
 276 }