drivers/crypto/nx/nx-842.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Cryptographic API for the NX-842 hardware compression.
   4  *
   5  * Copyright (C) IBM Corporation, 2011-2015
   6  *
   7  * Designer of the Power data compression engine:
   8  *   Bulent Abali <abali@us.ibm.com>
   9  *
  10  * Original Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
  11  *                   Seth Jennings <sjenning@linux.vnet.ibm.com>
  12  *
  13  * Rewrite: Dan Streetman <ddstreet@ieee.org>
  14  *
  15  * This is an interface to the NX-842 compression hardware in PowerPC
  16  * processors.  Most of the complexity of this drvier is due to the fact that
  17  * the NX-842 compression hardware requires the input and output data buffers
  18  * to be specifically aligned, to be a specific multiple in length, and within
  19  * specific minimum and maximum lengths.  Those restrictions, provided by the
  20  * nx-842 driver via nx842_constraints, mean this driver must use bounce
  21  * buffers and headers to correct misaligned in or out buffers, and to split
  22  * input buffers that are too large.
  23  *
  24  * This driver will fall back to software decompression if the hardware
  25  * decompression fails, so this driver's decompression should never fail as
  26  * long as the provided compressed buffer is valid.  Any compressed buffer
  27  * created by this driver will have a header (except ones where the input
  28  * perfectly matches the constraints); so users of this driver cannot simply
  29  * pass a compressed buffer created by this driver over to the 842 software
  30  * decompression library.  Instead, users must use this driver to decompress;
  31  * if the hardware fails or is unavailable, the compressed buffer will be
  32  * parsed and the header removed, and the raw 842 buffer(s) passed to the 842
  33  * software decompression library.
  34  *
  35  * This does not fall back to software compression, however, since the caller
  36  * of this function is specifically requesting hardware compression; if the
  37  * hardware compression fails, the caller can fall back to software
  38  * compression, and the raw 842 compressed buffer that the software compressor
  39  * creates can be passed to this driver for hardware decompression; any
  40  * buffer without our specific header magic is assumed to be a raw 842 buffer
  41  * and passed directly to the hardware.  Note that the software compression
  42  * library will produce a compressed buffer that is incompatible with the
  43  * hardware decompressor if the original input buffer length is not a multiple
  44  * of 8; if such a compressed buffer is passed to this driver for
  45  * decompression, the hardware will reject it and this driver will then pass
  46  * it over to the software library for decompression.
  47  */
  48
  49 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  50
  51 #include <linux/vmalloc.h>
  52 #include <linux/sw842.h>
  53 #include <linux/spinlock.h>
  54
  55 #include "nx-842.h"
  56
  57 /* The first 5 bits of this magic are 0x1f, which is an invalid 842 5-bit
  58  * template (see lib/842/842.h), so this magic number will never appear at
  59  * the start of a raw 842 compressed buffer.  That is important, as any buffer
  60  * passed to us without this magic is assumed to be a raw 842 compressed
  61  * buffer, and passed directly to the hardware to decompress.
  62  */
  63 #define NX842_CRYPTO_MAGIC      (0xf842)
  64 #define NX842_CRYPTO_HEADER_SIZE(g)                             \
  65         (sizeof(struct nx842_crypto_header) +                   \
  66          sizeof(struct nx842_crypto_header_group) * (g))
  67 #define NX842_CRYPTO_HEADER_MAX_SIZE                            \
  68         NX842_CRYPTO_HEADER_SIZE(NX842_CRYPTO_GROUP_MAX)
  69
  70 /* bounce buffer size */
  71 #define BOUNCE_BUFFER_ORDER     (2)
  72 #define BOUNCE_BUFFER_SIZE                                      \
  73         ((unsigned int)(PAGE_SIZE << BOUNCE_BUFFER_ORDER))
  74
  75 /* try longer on comp because we can fallback to sw decomp if hw is busy */
  76 #define COMP_BUSY_TIMEOUT       (250) /* ms */
  77 #define DECOMP_BUSY_TIMEOUT     (50) /* ms */
  78
  79 struct nx842_crypto_param {
  80         u8 *in;
  81         unsigned int iremain;
  82         u8 *out;
  83         unsigned int oremain;
  84         unsigned int ototal;
  85 };
  86
  87 static int update_param(struct nx842_crypto_param *p,
  88                         unsigned int slen, unsigned int dlen)
  89 {
  90         if (p->iremain < slen)
  91                 return -EOVERFLOW;
  92         if (p->oremain < dlen)
  93                 return -ENOSPC;
  94
  95         p->in += slen;
  96         p->iremain -= slen;
  97         p->out += dlen;
  98         p->oremain -= dlen;
  99         p->ototal += dlen;
 100
 101         return 0;
 102 }
 103
 104 int nx842_crypto_init(struct crypto_tfm *tfm, struct nx842_driver *driver)
 105 {
 106         struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm);
 107
 108         spin_lock_init(&ctx->lock);
 109         ctx->driver = driver;
 110         ctx->wmem = kmalloc(driver->workmem_size, GFP_KERNEL);
 111         ctx->sbounce = (u8 *)__get_free_pages(GFP_KERNEL, BOUNCE_BUFFER_ORDER);
 112         ctx->dbounce = (u8 *)__get_free_pages(GFP_KERNEL, BOUNCE_BUFFER_ORDER);
 113         if (!ctx->wmem || !ctx->sbounce || !ctx->dbounce) {
 114                 kfree(ctx->wmem);
 115                 free_page((unsigned long)ctx->sbounce);
 116                 free_page((unsigned long)ctx->dbounce);
 117                 return -ENOMEM;
 118         }
 119
 120         return 0;
 121 }
 122 EXPORT_SYMBOL_GPL(nx842_crypto_init);
 123
 124 void nx842_crypto_exit(struct crypto_tfm *tfm)
 125 {
 126         struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm);
 127
 128         kfree(ctx->wmem);
 129         free_page((unsigned long)ctx->sbounce);
 130         free_page((unsigned long)ctx->dbounce);
 131 }
 132 EXPORT_SYMBOL_GPL(nx842_crypto_exit);
 133
 134 static void check_constraints(struct nx842_constraints *c)
 135 {
 136         /* limit maximum, to always have enough bounce buffer to decompress */
 137         if (c->maximum > BOUNCE_BUFFER_SIZE)
 138                 c->maximum = BOUNCE_BUFFER_SIZE;
 139 }
 140
 141 static int nx842_crypto_add_header(struct nx842_crypto_header *hdr, u8 *buf)
 142 {
 143         int s = NX842_CRYPTO_HEADER_SIZE(hdr->groups);
 144
 145         /* compress should have added space for header */
 146         if (s > be16_to_cpu(hdr->group[0].padding)) {
 147                 pr_err("Internal error: no space for header\n");
 148                 return -EINVAL;
 149         }
 150
 151         memcpy(buf, hdr, s);
 152
 153         print_hex_dump_debug("header ", DUMP_PREFIX_OFFSET, 16, 1, buf, s, 0);
 154
 155         return 0;
 156 }
 157
 158 static int compress(struct nx842_crypto_ctx *ctx,
 159                     struct nx842_crypto_param *p,
 160                     struct nx842_crypto_header_group *g,
 161                     struct nx842_constraints *c,
 162                     u16 *ignore,
 163                     unsigned int hdrsize)
 164 {
 165         unsigned int slen = p->iremain, dlen = p->oremain, tmplen;
 166         unsigned int adj_slen = slen;
 167         u8 *src = p->in, *dst = p->out;
 168         int ret, dskip = 0;
 169         ktime_t timeout;
 170
 171         if (p->iremain == 0)
 172                 return -EOVERFLOW;
 173
 174         if (p->oremain == 0 || hdrsize + c->minimum > dlen)
 175                 return -ENOSPC;
 176
 177         if (slen % c->multiple)
 178                 adj_slen = round_up(slen, c->multiple);
 179         if (slen < c->minimum)
 180                 adj_slen = c->minimum;
 181         if (slen > c->maximum)
 182                 adj_slen = slen = c->maximum;
 183         if (adj_slen > slen || (u64)src % c->alignment) {
 184                 adj_slen = min(adj_slen, BOUNCE_BUFFER_SIZE);
 185                 slen = min(slen, BOUNCE_BUFFER_SIZE);
 186                 if (adj_slen > slen)
 187                         memset(ctx->sbounce + slen, 0, adj_slen - slen);
 188                 memcpy(ctx->sbounce, src, slen);
 189                 src = ctx->sbounce;
 190                 slen = adj_slen;
 191                 pr_debug("using comp sbounce buffer, len %x\n", slen);
 192         }
 193
 194         dst += hdrsize;
 195         dlen -= hdrsize;
 196
 197         if ((u64)dst % c->alignment) {
 198                 dskip = (int)(PTR_ALIGN(dst, c->alignment) - dst);
 199                 dst += dskip;
 200                 dlen -= dskip;
 201         }
 202         if (dlen % c->multiple)
 203                 dlen = round_down(dlen, c->multiple);
 204         if (dlen < c->minimum) {
 205 nospc:
 206                 dst = ctx->dbounce;
 207                 dlen = min(p->oremain, BOUNCE_BUFFER_SIZE);
 208                 dlen = round_down(dlen, c->multiple);
 209                 dskip = 0;
 210                 pr_debug("using comp dbounce buffer, len %x\n", dlen);
 211         }
 212         if (dlen > c->maximum)
 213                 dlen = c->maximum;
 214
 215         tmplen = dlen;
 216         timeout = ktime_add_ms(ktime_get(), COMP_BUSY_TIMEOUT);
 217         do {
 218                 dlen = tmplen; /* reset dlen, if we're retrying */
 219                 ret = ctx->driver->compress(src, slen, dst, &dlen, ctx->wmem);
 220                 /* possibly we should reduce the slen here, instead of
 221                  * retrying with the dbounce buffer?
 222                  */
 223                 if (ret == -ENOSPC && dst != ctx->dbounce)
 224                         goto nospc;
 225         } while (ret == -EBUSY && ktime_before(ktime_get(), timeout));
 226         if (ret)
 227                 return ret;
 228
 229         dskip += hdrsize;
 230
 231         if (dst == ctx->dbounce)
 232                 memcpy(p->out + dskip, dst, dlen);
 233
 234         g->padding = cpu_to_be16(dskip);
 235         g->compressed_length = cpu_to_be32(dlen);
 236         g->uncompressed_length = cpu_to_be32(slen);
 237
 238         if (p->iremain < slen) {
 239                 *ignore = slen - p->iremain;
 240                 slen = p->iremain;
 241         }
 242
 243         pr_debug("compress slen %x ignore %x dlen %x padding %x\n",
 244                  slen, *ignore, dlen, dskip);
 245
 246         return update_param(p, slen, dskip + dlen);
 247 }
 248
 249 int nx842_crypto_compress(struct crypto_tfm *tfm,
 250                           const u8 *src, unsigned int slen,
 251                           u8 *dst, unsigned int *dlen)
 252 {
 253         struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm);
 254         struct nx842_crypto_header *hdr = &ctx->header;
 255         struct nx842_crypto_param p;
 256         struct nx842_constraints c = *ctx->driver->constraints;
 257         unsigned int groups, hdrsize, h;
 258         int ret, n;
 259         bool add_header;
 260         u16 ignore = 0;
 261
 262         check_constraints(&c);
 263
 264         p.in = (u8 *)src;
 265         p.iremain = slen;
 266         p.out = dst;
 267         p.oremain = *dlen;
 268         p.ototal = 0;
 269
 270         *dlen = 0;
 271
 272         groups = min_t(unsigned int, NX842_CRYPTO_GROUP_MAX,
 273                        DIV_ROUND_UP(p.iremain, c.maximum));
 274         hdrsize = NX842_CRYPTO_HEADER_SIZE(groups);
 275
 276         spin_lock_bh(&ctx->lock);
 277
 278         /* skip adding header if the buffers meet all constraints */
 279         add_header = (p.iremain % c.multiple    ||
 280                       p.iremain < c.minimum     ||
 281                       p.iremain > c.maximum     ||
 282                       (u64)p.in % c.alignment   ||
 283                       p.oremain % c.multiple    ||
 284                       p.oremain < c.minimum     ||
 285                       p.oremain > c.maximum     ||
 286                       (u64)p.out % c.alignment);
 287
 288         hdr->magic = cpu_to_be16(NX842_CRYPTO_MAGIC);
 289         hdr->groups = 0;
 290         hdr->ignore = 0;
 291
 292         while (p.iremain > 0) {
 293                 n = hdr->groups++;
 294                 ret = -ENOSPC;
 295                 if (hdr->groups > NX842_CRYPTO_GROUP_MAX)
 296                         goto unlock;
 297
 298                 /* header goes before first group */
 299                 h = !n && add_header ? hdrsize : 0;
 300
 301                 if (ignore)
 302                         pr_warn("internal error, ignore is set %x\n", ignore);
 303
 304                 ret = compress(ctx, &p, &hdr->group[n], &c, &ignore, h);
 305                 if (ret)
 306                         goto unlock;
 307         }
 308
 309         if (!add_header && hdr->groups > 1) {
 310                 pr_err("Internal error: No header but multiple groups\n");
 311                 ret = -EINVAL;
 312                 goto unlock;
 313         }
 314
 315         /* ignore indicates the input stream needed to be padded */
 316         hdr->ignore = cpu_to_be16(ignore);
 317         if (ignore)
 318                 pr_debug("marked %d bytes as ignore\n", ignore);
 319
 320         if (add_header)
 321                 ret = nx842_crypto_add_header(hdr, dst);
 322         if (ret)
 323                 goto unlock;
 324
 325         *dlen = p.ototal;
 326
 327         pr_debug("compress total slen %x dlen %x\n", slen, *dlen);
 328
 329 unlock:
 330         spin_unlock_bh(&ctx->lock);
 331         return ret;
 332 }
 333 EXPORT_SYMBOL_GPL(nx842_crypto_compress);
 334
 335 static int decompress(struct nx842_crypto_ctx *ctx,
 336                       struct nx842_crypto_param *p,
 337                       struct nx842_crypto_header_group *g,
 338                       struct nx842_constraints *c,
 339                       u16 ignore)
 340 {
 341         unsigned int slen = be32_to_cpu(g->compressed_length);
 342         unsigned int required_len = be32_to_cpu(g->uncompressed_length);
 343         unsigned int dlen = p->oremain, tmplen;
 344         unsigned int adj_slen = slen;
 345         u8 *src = p->in, *dst = p->out;
 346         u16 padding = be16_to_cpu(g->padding);
 347         int ret, spadding = 0;
 348         ktime_t timeout;
 349
 350         if (!slen || !required_len)
 351                 return -EINVAL;
 352
 353         if (p->iremain <= 0 || padding + slen > p->iremain)
 354                 return -EOVERFLOW;
 355
 356         if (p->oremain <= 0 || required_len - ignore > p->oremain)
 357                 return -ENOSPC;
 358
 359         src += padding;
 360
 361         if (slen % c->multiple)
 362                 adj_slen = round_up(slen, c->multiple);
 363         if (slen < c->minimum)
 364                 adj_slen = c->minimum;
 365         if (slen > c->maximum)
 366                 goto usesw;
 367         if (slen < adj_slen || (u64)src % c->alignment) {
 368                 /* we can append padding bytes because the 842 format defines
 369                  * an "end" template (see lib/842/842_decompress.c) and will
 370                  * ignore any bytes following it.
 371                  */
 372                 if (slen < adj_slen)
 373                         memset(ctx->sbounce + slen, 0, adj_slen - slen);
 374                 memcpy(ctx->sbounce, src, slen);
 375                 src = ctx->sbounce;
 376                 spadding = adj_slen - slen;
 377                 slen = adj_slen;
 378                 pr_debug("using decomp sbounce buffer, len %x\n", slen);
 379         }
 380
 381         if (dlen % c->multiple)
 382                 dlen = round_down(dlen, c->multiple);
 383         if (dlen < required_len || (u64)dst % c->alignment) {
 384                 dst = ctx->dbounce;
 385                 dlen = min(required_len, BOUNCE_BUFFER_SIZE);
 386                 pr_debug("using decomp dbounce buffer, len %x\n", dlen);
 387         }
 388         if (dlen < c->minimum)
 389                 goto usesw;
 390         if (dlen > c->maximum)
 391                 dlen = c->maximum;
 392
 393         tmplen = dlen;
 394         timeout = ktime_add_ms(ktime_get(), DECOMP_BUSY_TIMEOUT);
 395         do {
 396                 dlen = tmplen; /* reset dlen, if we're retrying */
 397                 ret = ctx->driver->decompress(src, slen, dst, &dlen, ctx->wmem);
 398         } while (ret == -EBUSY && ktime_before(ktime_get(), timeout));
 399         if (ret) {
 400 usesw:
 401                 /* reset everything, sw doesn't have constraints */
 402                 src = p->in + padding;
 403                 slen = be32_to_cpu(g->compressed_length);
 404                 spadding = 0;
 405                 dst = p->out;
 406                 dlen = p->oremain;
 407                 if (dlen < required_len) { /* have ignore bytes */
 408                         dst = ctx->dbounce;
 409                         dlen = BOUNCE_BUFFER_SIZE;
 410                 }
 411                 pr_info_ratelimited("using software 842 decompression\n");
 412                 ret = sw842_decompress(src, slen, dst, &dlen);
 413         }
 414         if (ret)
 415                 return ret;
 416
 417         slen -= spadding;
 418
 419         dlen -= ignore;
 420         if (ignore)
 421                 pr_debug("ignoring last %x bytes\n", ignore);
 422
 423         if (dst == ctx->dbounce)
 424                 memcpy(p->out, dst, dlen);
 425
 426         pr_debug("decompress slen %x padding %x dlen %x ignore %x\n",
 427                  slen, padding, dlen, ignore);
 428
 429         return update_param(p, slen + padding, dlen);
 430 }
 431
 432 int nx842_crypto_decompress(struct crypto_tfm *tfm,
 433                             const u8 *src, unsigned int slen,
 434                             u8 *dst, unsigned int *dlen)
 435 {
 436         struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm);
 437         struct nx842_crypto_header *hdr;
 438         struct nx842_crypto_param p;
 439         struct nx842_constraints c = *ctx->driver->constraints;
 440         int n, ret, hdr_len;
 441         u16 ignore = 0;
 442
 443         check_constraints(&c);
 444
 445         p.in = (u8 *)src;
 446         p.iremain = slen;
 447         p.out = dst;
 448         p.oremain = *dlen;
 449         p.ototal = 0;
 450
 451         *dlen = 0;
 452
 453         hdr = (struct nx842_crypto_header *)src;
 454
 455         spin_lock_bh(&ctx->lock);
 456
 457         /* If it doesn't start with our header magic number, assume it's a raw
 458          * 842 compressed buffer and pass it directly to the hardware driver
 459          */
 460         if (be16_to_cpu(hdr->magic) != NX842_CRYPTO_MAGIC) {
 461                 struct nx842_crypto_header_group g = {
 462                         .padding =              0,
 463                         .compressed_length =    cpu_to_be32(p.iremain),
 464                         .uncompressed_length =  cpu_to_be32(p.oremain),
 465                 };
 466
 467                 ret = decompress(ctx, &p, &g, &c, 0);
 468                 if (ret)
 469                         goto unlock;
 470
 471                 goto success;
 472         }
 473
 474         if (!hdr->groups) {
 475                 pr_err("header has no groups\n");
 476                 ret = -EINVAL;
 477                 goto unlock;
 478         }
 479         if (hdr->groups > NX842_CRYPTO_GROUP_MAX) {
 480                 pr_err("header has too many groups %x, max %x\n",
 481                        hdr->groups, NX842_CRYPTO_GROUP_MAX);
 482                 ret = -EINVAL;
 483                 goto unlock;
 484         }
 485
 486         hdr_len = NX842_CRYPTO_HEADER_SIZE(hdr->groups);
 487         if (hdr_len > slen) {
 488                 ret = -EOVERFLOW;
 489                 goto unlock;
 490         }
 491
 492         memcpy(&ctx->header, src, hdr_len);
 493         hdr = &ctx->header;
 494
 495         for (n = 0; n < hdr->groups; n++) {
 496                 /* ignore applies to last group */
 497                 if (n + 1 == hdr->groups)
 498                         ignore = be16_to_cpu(hdr->ignore);
 499
 500                 ret = decompress(ctx, &p, &hdr->group[n], &c, ignore);
 501                 if (ret)
 502                         goto unlock;
 503         }
 504
 505 success:
 506         *dlen = p.ototal;
 507
 508         pr_debug("decompress total slen %x dlen %x\n", slen, *dlen);
 509
 510         ret = 0;
 511
 512 unlock:
 513         spin_unlock_bh(&ctx->lock);
 514
 515         return ret;
 516 }
 517 EXPORT_SYMBOL_GPL(nx842_crypto_decompress);
 518
 519 MODULE_LICENSE("GPL");
 520 MODULE_DESCRIPTION("IBM PowerPC Nest (NX) 842 Hardware Compression Driver");
 521 MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");