drivers/crypto/ccp/ccp-crypto-main.c

   1 /*
   2  * AMD Cryptographic Coprocessor (CCP) crypto API support
   3  *
   4  * Copyright (C) 2013 Advanced Micro Devices, Inc.
   5  *
   6  * Author: Tom Lendacky <thomas.lendacky@amd.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/kernel.h>
  16 #include <linux/list.h>
  17 #include <linux/ccp.h>
  18 #include <linux/scatterlist.h>
  19 #include <crypto/internal/hash.h>
  20
  21 #include "ccp-crypto.h"
  22
  23 MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
  24 MODULE_LICENSE("GPL");
  25 MODULE_VERSION("1.0.0");
  26 MODULE_DESCRIPTION("AMD Cryptographic Coprocessor crypto API support");
  27
  28 static unsigned int aes_disable;
  29 module_param(aes_disable, uint, 0444);
  30 MODULE_PARM_DESC(aes_disable, "Disable use of AES - any non-zero value");
  31
  32 static unsigned int sha_disable;
  33 module_param(sha_disable, uint, 0444);
  34 MODULE_PARM_DESC(sha_disable, "Disable use of SHA - any non-zero value");
  35
  36
  37 /* List heads for the supported algorithms */
  38 static LIST_HEAD(hash_algs);
  39 static LIST_HEAD(cipher_algs);
  40
  41 /* For any tfm, requests for that tfm must be returned on the order
  42  * received.  With multiple queues available, the CCP can process more
  43  * than one cmd at a time.  Therefore we must maintain a cmd list to insure
  44  * the proper ordering of requests on a given tfm.
  45  */
  46 struct ccp_crypto_queue {
  47         struct list_head cmds;
  48         struct list_head *backlog;
  49         unsigned int cmd_count;
  50 };
  51 #define CCP_CRYPTO_MAX_QLEN     100
  52
  53 static struct ccp_crypto_queue req_queue;
  54 static spinlock_t req_queue_lock;
  55
  56 struct ccp_crypto_cmd {
  57         struct list_head entry;
  58
  59         struct ccp_cmd *cmd;
  60
  61         /* Save the crypto_tfm and crypto_async_request addresses
  62          * separately to avoid any reference to a possibly invalid
  63          * crypto_async_request structure after invoking the request
  64          * callback
  65          */
  66         struct crypto_async_request *req;
  67         struct crypto_tfm *tfm;
  68
  69         /* Used for held command processing to determine state */
  70         int ret;
  71 };
  72
  73 struct ccp_crypto_cpu {
  74         struct work_struct work;
  75         struct completion completion;
  76         struct ccp_crypto_cmd *crypto_cmd;
  77         int err;
  78 };
  79
  80
  81 static inline bool ccp_crypto_success(int err)
  82 {
  83         if (err && (err != -EINPROGRESS) && (err != -EBUSY))
  84                 return false;
  85
  86         return true;
  87 }
  88
  89 static struct ccp_crypto_cmd *ccp_crypto_cmd_complete(
  90         struct ccp_crypto_cmd *crypto_cmd, struct ccp_crypto_cmd **backlog)
  91 {
  92         struct ccp_crypto_cmd *held = NULL, *tmp;
  93         unsigned long flags;
  94
  95         *backlog = NULL;
  96
  97         spin_lock_irqsave(&req_queue_lock, flags);
  98
  99         /* Held cmds will be after the current cmd in the queue so start
 100          * searching for a cmd with a matching tfm for submission.
 101          */
 102         tmp = crypto_cmd;
 103         list_for_each_entry_continue(tmp, &req_queue.cmds, entry) {
 104                 if (crypto_cmd->tfm != tmp->tfm)
 105                         continue;
 106                 held = tmp;
 107                 break;
 108         }
 109
 110         /* Process the backlog:
 111          *   Because cmds can be executed from any point in the cmd list
 112          *   special precautions have to be taken when handling the backlog.
 113          */
 114         if (req_queue.backlog != &req_queue.cmds) {
 115                 /* Skip over this cmd if it is the next backlog cmd */
 116                 if (req_queue.backlog == &crypto_cmd->entry)
 117                         req_queue.backlog = crypto_cmd->entry.next;
 118
 119                 *backlog = container_of(req_queue.backlog,
 120                                         struct ccp_crypto_cmd, entry);
 121                 req_queue.backlog = req_queue.backlog->next;
 122
 123                 /* Skip over this cmd if it is now the next backlog cmd */
 124                 if (req_queue.backlog == &crypto_cmd->entry)
 125                         req_queue.backlog = crypto_cmd->entry.next;
 126         }
 127
 128         /* Remove the cmd entry from the list of cmds */
 129         req_queue.cmd_count--;
 130         list_del(&crypto_cmd->entry);
 131
 132         spin_unlock_irqrestore(&req_queue_lock, flags);
 133
 134         return held;
 135 }
 136
 137 static void ccp_crypto_complete(void *data, int err)
 138 {
 139         struct ccp_crypto_cmd *crypto_cmd = data;
 140         struct ccp_crypto_cmd *held, *next, *backlog;
 141         struct crypto_async_request *req = crypto_cmd->req;
 142         struct ccp_ctx *ctx = crypto_tfm_ctx(req->tfm);
 143         int ret;
 144
 145         if (err == -EINPROGRESS) {
 146                 /* Only propogate the -EINPROGRESS if necessary */
 147                 if (crypto_cmd->ret == -EBUSY) {
 148                         crypto_cmd->ret = -EINPROGRESS;
 149                         req->complete(req, -EINPROGRESS);
 150                 }
 151
 152                 return;
 153         }
 154
 155         /* Operation has completed - update the queue before invoking
 156          * the completion callbacks and retrieve the next cmd (cmd with
 157          * a matching tfm) that can be submitted to the CCP.
 158          */
 159         held = ccp_crypto_cmd_complete(crypto_cmd, &backlog);
 160         if (backlog) {
 161                 backlog->ret = -EINPROGRESS;
 162                 backlog->req->complete(backlog->req, -EINPROGRESS);
 163         }
 164
 165         /* Transition the state from -EBUSY to -EINPROGRESS first */
 166         if (crypto_cmd->ret == -EBUSY)
 167                 req->complete(req, -EINPROGRESS);
 168
 169         /* Completion callbacks */
 170         ret = err;
 171         if (ctx->complete)
 172                 ret = ctx->complete(req, ret);
 173         req->complete(req, ret);
 174
 175         /* Submit the next cmd */
 176         while (held) {
 177                 /* Since we have already queued the cmd, we must indicate that
 178                  * we can backlog so as not to "lose" this request.
 179                  */
 180                 held->cmd->flags |= CCP_CMD_MAY_BACKLOG;
 181                 ret = ccp_enqueue_cmd(held->cmd);
 182                 if (ccp_crypto_success(ret))
 183                         break;
 184
 185                 /* Error occurred, report it and get the next entry */
 186                 ctx = crypto_tfm_ctx(held->req->tfm);
 187                 if (ctx->complete)
 188                         ret = ctx->complete(held->req, ret);
 189                 held->req->complete(held->req, ret);
 190
 191                 next = ccp_crypto_cmd_complete(held, &backlog);
 192                 if (backlog) {
 193                         backlog->ret = -EINPROGRESS;
 194                         backlog->req->complete(backlog->req, -EINPROGRESS);
 195                 }
 196
 197                 kfree(held);
 198                 held = next;
 199         }
 200
 201         kfree(crypto_cmd);
 202 }
 203
 204 static int ccp_crypto_enqueue_cmd(struct ccp_crypto_cmd *crypto_cmd)
 205 {
 206         struct ccp_crypto_cmd *active = NULL, *tmp;
 207         unsigned long flags;
 208         bool free_cmd = true;
 209         int ret;
 210
 211         spin_lock_irqsave(&req_queue_lock, flags);
 212
 213         /* Check if the cmd can/should be queued */
 214         if (req_queue.cmd_count >= CCP_CRYPTO_MAX_QLEN) {
 215                 ret = -EBUSY;
 216                 if (!(crypto_cmd->cmd->flags & CCP_CMD_MAY_BACKLOG))
 217                         goto e_lock;
 218         }
 219
 220         /* Look for an entry with the same tfm.  If there is a cmd
 221          * with the same tfm in the list then the current cmd cannot
 222          * be submitted to the CCP yet.
 223          */
 224         list_for_each_entry(tmp, &req_queue.cmds, entry) {
 225                 if (crypto_cmd->tfm != tmp->tfm)
 226                         continue;
 227                 active = tmp;
 228                 break;
 229         }
 230
 231         ret = -EINPROGRESS;
 232         if (!active) {
 233                 ret = ccp_enqueue_cmd(crypto_cmd->cmd);
 234                 if (!ccp_crypto_success(ret))
 235                         goto e_lock;    /* Error, don't queue it */
 236                 if ((ret == -EBUSY) &&
 237                     !(crypto_cmd->cmd->flags & CCP_CMD_MAY_BACKLOG))
 238                         goto e_lock;    /* Not backlogging, don't queue it */
 239         }
 240
 241         if (req_queue.cmd_count >= CCP_CRYPTO_MAX_QLEN) {
 242                 ret = -EBUSY;
 243                 if (req_queue.backlog == &req_queue.cmds)
 244                         req_queue.backlog = &crypto_cmd->entry;
 245         }
 246         crypto_cmd->ret = ret;
 247
 248         req_queue.cmd_count++;
 249         list_add_tail(&crypto_cmd->entry, &req_queue.cmds);
 250
 251         free_cmd = false;
 252
 253 e_lock:
 254         spin_unlock_irqrestore(&req_queue_lock, flags);
 255
 256         if (free_cmd)
 257                 kfree(crypto_cmd);
 258
 259         return ret;
 260 }
 261
 262 /**
 263  * ccp_crypto_enqueue_request - queue an crypto async request for processing
 264  *                              by the CCP
 265  *
 266  * @req: crypto_async_request struct to be processed
 267  * @cmd: ccp_cmd struct to be sent to the CCP
 268  */
 269 int ccp_crypto_enqueue_request(struct crypto_async_request *req,
 270                                struct ccp_cmd *cmd)
 271 {
 272         struct ccp_crypto_cmd *crypto_cmd;
 273         gfp_t gfp;
 274
 275         gfp = req->flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL : GFP_ATOMIC;
 276
 277         crypto_cmd = kzalloc(sizeof(*crypto_cmd), gfp);
 278         if (!crypto_cmd)
 279                 return -ENOMEM;
 280
 281         /* The tfm pointer must be saved and not referenced from the
 282          * crypto_async_request (req) pointer because it is used after
 283          * completion callback for the request and the req pointer
 284          * might not be valid anymore.
 285          */
 286         crypto_cmd->cmd = cmd;
 287         crypto_cmd->req = req;
 288         crypto_cmd->tfm = req->tfm;
 289
 290         cmd->callback = ccp_crypto_complete;
 291         cmd->data = crypto_cmd;
 292
 293         if (req->flags & CRYPTO_TFM_REQ_MAY_BACKLOG)
 294                 cmd->flags |= CCP_CMD_MAY_BACKLOG;
 295         else
 296                 cmd->flags &= ~CCP_CMD_MAY_BACKLOG;
 297
 298         return ccp_crypto_enqueue_cmd(crypto_cmd);
 299 }
 300
 301 struct scatterlist *ccp_crypto_sg_table_add(struct sg_table *table,
 302                                             struct scatterlist *sg_add)
 303 {
 304         struct scatterlist *sg, *sg_last = NULL;
 305
 306         for (sg = table->sgl; sg; sg = sg_next(sg))
 307                 if (!sg_page(sg))
 308                         break;
 309         BUG_ON(!sg);
 310
 311         for (; sg && sg_add; sg = sg_next(sg), sg_add = sg_next(sg_add)) {
 312                 sg_set_page(sg, sg_page(sg_add), sg_add->length,
 313                             sg_add->offset);
 314                 sg_last = sg;
 315         }
 316         BUG_ON(sg_add);
 317
 318         return sg_last;
 319 }
 320
 321 static int ccp_register_algs(void)
 322 {
 323         int ret;
 324
 325         if (!aes_disable) {
 326                 ret = ccp_register_aes_algs(&cipher_algs);
 327                 if (ret)
 328                         return ret;
 329
 330                 ret = ccp_register_aes_cmac_algs(&hash_algs);
 331                 if (ret)
 332                         return ret;
 333
 334                 ret = ccp_register_aes_xts_algs(&cipher_algs);
 335                 if (ret)
 336                         return ret;
 337         }
 338
 339         if (!sha_disable) {
 340                 ret = ccp_register_sha_algs(&hash_algs);
 341                 if (ret)
 342                         return ret;
 343         }
 344
 345         return 0;
 346 }
 347
 348 static void ccp_unregister_algs(void)
 349 {
 350         struct ccp_crypto_ahash_alg *ahash_alg, *ahash_tmp;
 351         struct ccp_crypto_ablkcipher_alg *ablk_alg, *ablk_tmp;
 352
 353         list_for_each_entry_safe(ahash_alg, ahash_tmp, &hash_algs, entry) {
 354                 crypto_unregister_ahash(&ahash_alg->alg);
 355                 list_del(&ahash_alg->entry);
 356                 kfree(ahash_alg);
 357         }
 358
 359         list_for_each_entry_safe(ablk_alg, ablk_tmp, &cipher_algs, entry) {
 360                 crypto_unregister_alg(&ablk_alg->alg);
 361                 list_del(&ablk_alg->entry);
 362                 kfree(ablk_alg);
 363         }
 364 }
 365
 366 static int ccp_crypto_init(void)
 367 {
 368         int ret;
 369
 370         ret = ccp_present();
 371         if (ret)
 372                 return ret;
 373
 374         spin_lock_init(&req_queue_lock);
 375         INIT_LIST_HEAD(&req_queue.cmds);
 376         req_queue.backlog = &req_queue.cmds;
 377         req_queue.cmd_count = 0;
 378
 379         ret = ccp_register_algs();
 380         if (ret)
 381                 ccp_unregister_algs();
 382
 383         return ret;
 384 }
 385
 386 static void ccp_crypto_exit(void)
 387 {
 388         ccp_unregister_algs();
 389 }
 390
 391 module_init(ccp_crypto_init);
 392 module_exit(ccp_crypto_exit);