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 = 255 container_of(&ctx->header, 256 struct nx842_crypto_header, hdr); 257 struct nx842_crypto_param p; 258 struct nx842_constraints c = *ctx->driver->constraints; 259 unsigned int groups, hdrsize, h; 260 int ret, n; 261 bool add_header; 262 u16 ignore = 0; 263 264 check_constraints(&c); 265 266 p.in = (u8 *)src; 267 p.iremain = slen; 268 p.out = dst; 269 p.oremain = *dlen; 270 p.ototal = 0; 271 272 *dlen = 0; 273 274 groups = min_t(unsigned int, NX842_CRYPTO_GROUP_MAX, 275 DIV_ROUND_UP(p.iremain, c.maximum)); 276 hdrsize = NX842_CRYPTO_HEADER_SIZE(groups); 277 278 spin_lock_bh(&ctx->lock); 279 280 /* skip adding header if the buffers meet all constraints */ 281 add_header = (p.iremain % c.multiple || 282 p.iremain < c.minimum || 283 p.iremain > c.maximum || 284 (u64)p.in % c.alignment || 285 p.oremain % c.multiple || 286 p.oremain < c.minimum || 287 p.oremain > c.maximum || 288 (u64)p.out % c.alignment); 289 290 hdr->magic = cpu_to_be16(NX842_CRYPTO_MAGIC); 291 hdr->groups = 0; 292 hdr->ignore = 0; 293 294 while (p.iremain > 0) { 295 n = hdr->groups++; 296 ret = -ENOSPC; 297 if (hdr->groups > NX842_CRYPTO_GROUP_MAX) 298 goto unlock; 299 300 /* header goes before first group */ 301 h = !n && add_header ? hdrsize : 0; 302 303 if (ignore) 304 pr_warn("internal error, ignore is set %x\n", ignore); 305 306 ret = compress(ctx, &p, &hdr->group[n], &c, &ignore, h); 307 if (ret) 308 goto unlock; 309 } 310 311 if (!add_header && hdr->groups > 1) { 312 pr_err("Internal error: No header but multiple groups\n"); 313 ret = -EINVAL; 314 goto unlock; 315 } 316 317 /* ignore indicates the input stream needed to be padded */ 318 hdr->ignore = cpu_to_be16(ignore); 319 if (ignore) 320 pr_debug("marked %d bytes as ignore\n", ignore); 321 322 if (add_header) 323 ret = nx842_crypto_add_header(hdr, dst); 324 if (ret) 325 goto unlock; 326 327 *dlen = p.ototal; 328 329 pr_debug("compress total slen %x dlen %x\n", slen, *dlen); 330 331 unlock: 332 spin_unlock_bh(&ctx->lock); 333 return ret; 334 } 335 EXPORT_SYMBOL_GPL(nx842_crypto_compress); 336 337 static int decompress(struct nx842_crypto_ctx *ctx, 338 struct nx842_crypto_param *p, 339 struct nx842_crypto_header_group *g, 340 struct nx842_constraints *c, 341 u16 ignore) 342 { 343 unsigned int slen = be32_to_cpu(g->compressed_length); 344 unsigned int required_len = be32_to_cpu(g->uncompressed_length); 345 unsigned int dlen = p->oremain, tmplen; 346 unsigned int adj_slen = slen; 347 u8 *src = p->in, *dst = p->out; 348 u16 padding = be16_to_cpu(g->padding); 349 int ret, spadding = 0; 350 ktime_t timeout; 351 352 if (!slen || !required_len) 353 return -EINVAL; 354 355 if (p->iremain <= 0 || padding + slen > p->iremain) 356 return -EOVERFLOW; 357 358 if (p->oremain <= 0 || required_len - ignore > p->oremain) 359 return -ENOSPC; 360 361 src += padding; 362 363 if (slen % c->multiple) 364 adj_slen = round_up(slen, c->multiple); 365 if (slen < c->minimum) 366 adj_slen = c->minimum; 367 if (slen > c->maximum) 368 goto usesw; 369 if (slen < adj_slen || (u64)src % c->alignment) { 370 /* we can append padding bytes because the 842 format defines 371 * an "end" template (see lib/842/842_decompress.c) and will 372 * ignore any bytes following it. 373 */ 374 if (slen < adj_slen) 375 memset(ctx->sbounce + slen, 0, adj_slen - slen); 376 memcpy(ctx->sbounce, src, slen); 377 src = ctx->sbounce; 378 spadding = adj_slen - slen; 379 slen = adj_slen; 380 pr_debug("using decomp sbounce buffer, len %x\n", slen); 381 } 382 383 if (dlen % c->multiple) 384 dlen = round_down(dlen, c->multiple); 385 if (dlen < required_len || (u64)dst % c->alignment) { 386 dst = ctx->dbounce; 387 dlen = min(required_len, BOUNCE_BUFFER_SIZE); 388 pr_debug("using decomp dbounce buffer, len %x\n", dlen); 389 } 390 if (dlen < c->minimum) 391 goto usesw; 392 if (dlen > c->maximum) 393 dlen = c->maximum; 394 395 tmplen = dlen; 396 timeout = ktime_add_ms(ktime_get(), DECOMP_BUSY_TIMEOUT); 397 do { 398 dlen = tmplen; /* reset dlen, if we're retrying */ 399 ret = ctx->driver->decompress(src, slen, dst, &dlen, ctx->wmem); 400 } while (ret == -EBUSY && ktime_before(ktime_get(), timeout)); 401 if (ret) { 402 usesw: 403 /* reset everything, sw doesn't have constraints */ 404 src = p->in + padding; 405 slen = be32_to_cpu(g->compressed_length); 406 spadding = 0; 407 dst = p->out; 408 dlen = p->oremain; 409 if (dlen < required_len) { /* have ignore bytes */ 410 dst = ctx->dbounce; 411 dlen = BOUNCE_BUFFER_SIZE; 412 } 413 pr_info_ratelimited("using software 842 decompression\n"); 414 ret = sw842_decompress(src, slen, dst, &dlen); 415 } 416 if (ret) 417 return ret; 418 419 slen -= spadding; 420 421 dlen -= ignore; 422 if (ignore) 423 pr_debug("ignoring last %x bytes\n", ignore); 424 425 if (dst == ctx->dbounce) 426 memcpy(p->out, dst, dlen); 427 428 pr_debug("decompress slen %x padding %x dlen %x ignore %x\n", 429 slen, padding, dlen, ignore); 430 431 return update_param(p, slen + padding, dlen); 432 } 433 434 int nx842_crypto_decompress(struct crypto_tfm *tfm, 435 const u8 *src, unsigned int slen, 436 u8 *dst, unsigned int *dlen) 437 { 438 struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm); 439 struct nx842_crypto_header *hdr; 440 struct nx842_crypto_param p; 441 struct nx842_constraints c = *ctx->driver->constraints; 442 int n, ret, hdr_len; 443 u16 ignore = 0; 444 445 check_constraints(&c); 446 447 p.in = (u8 *)src; 448 p.iremain = slen; 449 p.out = dst; 450 p.oremain = *dlen; 451 p.ototal = 0; 452 453 *dlen = 0; 454 455 hdr = (struct nx842_crypto_header *)src; 456 457 spin_lock_bh(&ctx->lock); 458 459 /* If it doesn't start with our header magic number, assume it's a raw 460 * 842 compressed buffer and pass it directly to the hardware driver 461 */ 462 if (be16_to_cpu(hdr->magic) != NX842_CRYPTO_MAGIC) { 463 struct nx842_crypto_header_group g = { 464 .padding = 0, 465 .compressed_length = cpu_to_be32(p.iremain), 466 .uncompressed_length = cpu_to_be32(p.oremain), 467 }; 468 469 ret = decompress(ctx, &p, &g, &c, 0); 470 if (ret) 471 goto unlock; 472 473 goto success; 474 } 475 476 if (!hdr->groups) { 477 pr_err("header has no groups\n"); 478 ret = -EINVAL; 479 goto unlock; 480 } 481 if (hdr->groups > NX842_CRYPTO_GROUP_MAX) { 482 pr_err("header has too many groups %x, max %x\n", 483 hdr->groups, NX842_CRYPTO_GROUP_MAX); 484 ret = -EINVAL; 485 goto unlock; 486 } 487 488 hdr_len = NX842_CRYPTO_HEADER_SIZE(hdr->groups); 489 if (hdr_len > slen) { 490 ret = -EOVERFLOW; 491 goto unlock; 492 } 493 494 memcpy(&ctx->header, src, hdr_len); 495 hdr = container_of(&ctx->header, struct nx842_crypto_header, hdr); 496 497 for (n = 0; n < hdr->groups; n++) { 498 /* ignore applies to last group */ 499 if (n + 1 == hdr->groups) 500 ignore = be16_to_cpu(hdr->ignore); 501 502 ret = decompress(ctx, &p, &hdr->group[n], &c, ignore); 503 if (ret) 504 goto unlock; 505 } 506 507 success: 508 *dlen = p.ototal; 509 510 pr_debug("decompress total slen %x dlen %x\n", slen, *dlen); 511 512 ret = 0; 513 514 unlock: 515 spin_unlock_bh(&ctx->lock); 516 517 return ret; 518 } 519 EXPORT_SYMBOL_GPL(nx842_crypto_decompress); 520 521 MODULE_LICENSE("GPL"); 522 MODULE_DESCRIPTION("IBM PowerPC Nest (NX) 842 Hardware Compression Driver"); 523 MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>"); 524