1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2019 HUAWEI, Inc. 4 * https://www.huawei.com/ 5 */ 6 #include "compress.h" 7 #include <linux/module.h> 8 #include <linux/lz4.h> 9 10 #ifndef LZ4_DISTANCE_MAX /* history window size */ 11 #define LZ4_DISTANCE_MAX 65535 /* set to maximum value by default */ 12 #endif 13 14 #define LZ4_MAX_DISTANCE_PAGES (DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1) 15 #ifndef LZ4_DECOMPRESS_INPLACE_MARGIN 16 #define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize) (((srcsize) >> 8) + 32) 17 #endif 18 19 struct z_erofs_lz4_decompress_ctx { 20 struct z_erofs_decompress_req *rq; 21 /* # of encoded, decoded pages */ 22 unsigned int inpages, outpages; 23 /* decoded block total length (used for in-place decompression) */ 24 unsigned int oend; 25 }; 26 27 static int z_erofs_load_lz4_config(struct super_block *sb, 28 struct erofs_super_block *dsb, void *data, int size) 29 { 30 struct erofs_sb_info *sbi = EROFS_SB(sb); 31 struct z_erofs_lz4_cfgs *lz4 = data; 32 u16 distance; 33 34 if (lz4) { 35 if (size < sizeof(struct z_erofs_lz4_cfgs)) { 36 erofs_err(sb, "invalid lz4 cfgs, size=%u", size); 37 return -EINVAL; 38 } 39 distance = le16_to_cpu(lz4->max_distance); 40 41 sbi->lz4.max_pclusterblks = le16_to_cpu(lz4->max_pclusterblks); 42 if (!sbi->lz4.max_pclusterblks) { 43 sbi->lz4.max_pclusterblks = 1; /* reserved case */ 44 } else if (sbi->lz4.max_pclusterblks > 45 erofs_blknr(sb, Z_EROFS_PCLUSTER_MAX_SIZE)) { 46 erofs_err(sb, "too large lz4 pclusterblks %u", 47 sbi->lz4.max_pclusterblks); 48 return -EINVAL; 49 } 50 } else { 51 distance = le16_to_cpu(dsb->u1.lz4_max_distance); 52 sbi->lz4.max_pclusterblks = 1; 53 } 54 55 sbi->lz4.max_distance_pages = distance ? 56 DIV_ROUND_UP(distance, PAGE_SIZE) + 1 : 57 LZ4_MAX_DISTANCE_PAGES; 58 return erofs_pcpubuf_growsize(sbi->lz4.max_pclusterblks); 59 } 60 61 /* 62 * Fill all gaps with bounce pages if it's a sparse page list. Also check if 63 * all physical pages are consecutive, which can be seen for moderate CR. 64 */ 65 static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx, 66 struct page **pagepool) 67 { 68 struct z_erofs_decompress_req *rq = ctx->rq; 69 struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL }; 70 unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES, 71 BITS_PER_LONG)] = { 0 }; 72 unsigned int lz4_max_distance_pages = 73 EROFS_SB(rq->sb)->lz4.max_distance_pages; 74 void *kaddr = NULL; 75 unsigned int i, j, top; 76 77 top = 0; 78 for (i = j = 0; i < ctx->outpages; ++i, ++j) { 79 struct page *const page = rq->out[i]; 80 struct page *victim; 81 82 if (j >= lz4_max_distance_pages) 83 j = 0; 84 85 /* 'valid' bounced can only be tested after a complete round */ 86 if (!rq->fillgaps && test_bit(j, bounced)) { 87 DBG_BUGON(i < lz4_max_distance_pages); 88 DBG_BUGON(top >= lz4_max_distance_pages); 89 availables[top++] = rq->out[i - lz4_max_distance_pages]; 90 } 91 92 if (page) { 93 __clear_bit(j, bounced); 94 if (!PageHighMem(page)) { 95 if (!i) { 96 kaddr = page_address(page); 97 continue; 98 } 99 if (kaddr && 100 kaddr + PAGE_SIZE == page_address(page)) { 101 kaddr += PAGE_SIZE; 102 continue; 103 } 104 } 105 kaddr = NULL; 106 continue; 107 } 108 kaddr = NULL; 109 __set_bit(j, bounced); 110 111 if (top) { 112 victim = availables[--top]; 113 get_page(victim); 114 } else { 115 victim = erofs_allocpage(pagepool, 116 GFP_KERNEL | __GFP_NOFAIL); 117 set_page_private(victim, Z_EROFS_SHORTLIVED_PAGE); 118 } 119 rq->out[i] = victim; 120 } 121 return kaddr ? 1 : 0; 122 } 123 124 static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx, 125 void *inpage, void *out, unsigned int *inputmargin, 126 int *maptype, bool may_inplace) 127 { 128 struct z_erofs_decompress_req *rq = ctx->rq; 129 unsigned int omargin, total, i; 130 struct page **in; 131 void *src, *tmp; 132 133 if (rq->inplace_io) { 134 omargin = PAGE_ALIGN(ctx->oend) - ctx->oend; 135 if (rq->partial_decoding || !may_inplace || 136 omargin < LZ4_DECOMPRESS_INPLACE_MARGIN(rq->inputsize)) 137 goto docopy; 138 139 for (i = 0; i < ctx->inpages; ++i) 140 if (rq->out[ctx->outpages - ctx->inpages + i] != 141 rq->in[i]) 142 goto docopy; 143 kunmap_local(inpage); 144 *maptype = 3; 145 return out + ((ctx->outpages - ctx->inpages) << PAGE_SHIFT); 146 } 147 148 if (ctx->inpages <= 1) { 149 *maptype = 0; 150 return inpage; 151 } 152 kunmap_local(inpage); 153 src = erofs_vm_map_ram(rq->in, ctx->inpages); 154 if (!src) 155 return ERR_PTR(-ENOMEM); 156 *maptype = 1; 157 return src; 158 159 docopy: 160 /* Or copy compressed data which can be overlapped to per-CPU buffer */ 161 in = rq->in; 162 src = erofs_get_pcpubuf(ctx->inpages); 163 if (!src) { 164 DBG_BUGON(1); 165 kunmap_local(inpage); 166 return ERR_PTR(-EFAULT); 167 } 168 169 tmp = src; 170 total = rq->inputsize; 171 while (total) { 172 unsigned int page_copycnt = 173 min_t(unsigned int, total, PAGE_SIZE - *inputmargin); 174 175 if (!inpage) 176 inpage = kmap_local_page(*in); 177 memcpy(tmp, inpage + *inputmargin, page_copycnt); 178 kunmap_local(inpage); 179 inpage = NULL; 180 tmp += page_copycnt; 181 total -= page_copycnt; 182 ++in; 183 *inputmargin = 0; 184 } 185 *maptype = 2; 186 return src; 187 } 188 189 /* 190 * Get the exact inputsize with zero_padding feature. 191 * - For LZ4, it should work if zero_padding feature is on (5.3+); 192 * - For MicroLZMA, it'd be enabled all the time. 193 */ 194 int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf, 195 unsigned int padbufsize) 196 { 197 const char *padend; 198 199 padend = memchr_inv(padbuf, 0, padbufsize); 200 if (!padend) 201 return -EFSCORRUPTED; 202 rq->inputsize -= padend - padbuf; 203 rq->pageofs_in += padend - padbuf; 204 return 0; 205 } 206 207 static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx, 208 u8 *dst) 209 { 210 struct z_erofs_decompress_req *rq = ctx->rq; 211 bool support_0padding = false, may_inplace = false; 212 unsigned int inputmargin; 213 u8 *out, *headpage, *src; 214 int ret, maptype; 215 216 DBG_BUGON(*rq->in == NULL); 217 headpage = kmap_local_page(*rq->in); 218 219 /* LZ4 decompression inplace is only safe if zero_padding is enabled */ 220 if (erofs_sb_has_zero_padding(EROFS_SB(rq->sb))) { 221 support_0padding = true; 222 ret = z_erofs_fixup_insize(rq, headpage + rq->pageofs_in, 223 min_t(unsigned int, rq->inputsize, 224 rq->sb->s_blocksize - rq->pageofs_in)); 225 if (ret) { 226 kunmap_local(headpage); 227 return ret; 228 } 229 may_inplace = !((rq->pageofs_in + rq->inputsize) & 230 (rq->sb->s_blocksize - 1)); 231 } 232 233 inputmargin = rq->pageofs_in; 234 src = z_erofs_lz4_handle_overlap(ctx, headpage, dst, &inputmargin, 235 &maptype, may_inplace); 236 if (IS_ERR(src)) 237 return PTR_ERR(src); 238 239 out = dst + rq->pageofs_out; 240 /* legacy format could compress extra data in a pcluster. */ 241 if (rq->partial_decoding || !support_0padding) 242 ret = LZ4_decompress_safe_partial(src + inputmargin, out, 243 rq->inputsize, rq->outputsize, rq->outputsize); 244 else 245 ret = LZ4_decompress_safe(src + inputmargin, out, 246 rq->inputsize, rq->outputsize); 247 248 if (ret != rq->outputsize) { 249 erofs_err(rq->sb, "failed to decompress %d in[%u, %u] out[%u]", 250 ret, rq->inputsize, inputmargin, rq->outputsize); 251 252 print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET, 253 16, 1, src + inputmargin, rq->inputsize, true); 254 print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET, 255 16, 1, out, rq->outputsize, true); 256 257 if (ret >= 0) 258 memset(out + ret, 0, rq->outputsize - ret); 259 ret = -EIO; 260 } else { 261 ret = 0; 262 } 263 264 if (maptype == 0) { 265 kunmap_local(headpage); 266 } else if (maptype == 1) { 267 vm_unmap_ram(src, ctx->inpages); 268 } else if (maptype == 2) { 269 erofs_put_pcpubuf(src); 270 } else if (maptype != 3) { 271 DBG_BUGON(1); 272 return -EFAULT; 273 } 274 return ret; 275 } 276 277 static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, 278 struct page **pagepool) 279 { 280 struct z_erofs_lz4_decompress_ctx ctx; 281 unsigned int dst_maptype; 282 void *dst; 283 int ret; 284 285 ctx.rq = rq; 286 ctx.oend = rq->pageofs_out + rq->outputsize; 287 ctx.outpages = PAGE_ALIGN(ctx.oend) >> PAGE_SHIFT; 288 ctx.inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT; 289 290 /* one optimized fast path only for non bigpcluster cases yet */ 291 if (ctx.inpages == 1 && ctx.outpages == 1 && !rq->inplace_io) { 292 DBG_BUGON(!*rq->out); 293 dst = kmap_local_page(*rq->out); 294 dst_maptype = 0; 295 goto dstmap_out; 296 } 297 298 /* general decoding path which can be used for all cases */ 299 ret = z_erofs_lz4_prepare_dstpages(&ctx, pagepool); 300 if (ret < 0) { 301 return ret; 302 } else if (ret > 0) { 303 dst = page_address(*rq->out); 304 dst_maptype = 1; 305 } else { 306 dst = erofs_vm_map_ram(rq->out, ctx.outpages); 307 if (!dst) 308 return -ENOMEM; 309 dst_maptype = 2; 310 } 311 312 dstmap_out: 313 ret = z_erofs_lz4_decompress_mem(&ctx, dst); 314 if (!dst_maptype) 315 kunmap_local(dst); 316 else if (dst_maptype == 2) 317 vm_unmap_ram(dst, ctx.outpages); 318 return ret; 319 } 320 321 static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq, 322 struct page **pagepool) 323 { 324 const unsigned int inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT; 325 const unsigned int outpages = 326 PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; 327 const unsigned int righthalf = min_t(unsigned int, rq->outputsize, 328 PAGE_SIZE - rq->pageofs_out); 329 const unsigned int lefthalf = rq->outputsize - righthalf; 330 const unsigned int interlaced_offset = 331 rq->alg == Z_EROFS_COMPRESSION_SHIFTED ? 0 : rq->pageofs_out; 332 u8 *src; 333 334 if (outpages > 2 && rq->alg == Z_EROFS_COMPRESSION_SHIFTED) { 335 DBG_BUGON(1); 336 return -EFSCORRUPTED; 337 } 338 339 if (rq->out[0] == *rq->in) { 340 DBG_BUGON(rq->pageofs_out); 341 return 0; 342 } 343 344 src = kmap_local_page(rq->in[inpages - 1]) + rq->pageofs_in; 345 if (rq->out[0]) 346 memcpy_to_page(rq->out[0], rq->pageofs_out, 347 src + interlaced_offset, righthalf); 348 349 if (outpages > inpages) { 350 DBG_BUGON(!rq->out[outpages - 1]); 351 if (rq->out[outpages - 1] != rq->in[inpages - 1]) { 352 memcpy_to_page(rq->out[outpages - 1], 0, src + 353 (interlaced_offset ? 0 : righthalf), 354 lefthalf); 355 } else if (!interlaced_offset) { 356 memmove(src, src + righthalf, lefthalf); 357 flush_dcache_page(rq->in[inpages - 1]); 358 } 359 } 360 kunmap_local(src); 361 return 0; 362 } 363 364 const struct z_erofs_decompressor erofs_decompressors[] = { 365 [Z_EROFS_COMPRESSION_SHIFTED] = { 366 .decompress = z_erofs_transform_plain, 367 .name = "shifted" 368 }, 369 [Z_EROFS_COMPRESSION_INTERLACED] = { 370 .decompress = z_erofs_transform_plain, 371 .name = "interlaced" 372 }, 373 [Z_EROFS_COMPRESSION_LZ4] = { 374 .config = z_erofs_load_lz4_config, 375 .decompress = z_erofs_lz4_decompress, 376 .name = "lz4" 377 }, 378 #ifdef CONFIG_EROFS_FS_ZIP_LZMA 379 [Z_EROFS_COMPRESSION_LZMA] = { 380 .config = z_erofs_load_lzma_config, 381 .decompress = z_erofs_lzma_decompress, 382 .name = "lzma" 383 }, 384 #endif 385 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE 386 [Z_EROFS_COMPRESSION_DEFLATE] = { 387 .config = z_erofs_load_deflate_config, 388 .decompress = z_erofs_deflate_decompress, 389 .name = "deflate" 390 }, 391 #endif 392 }; 393 394 int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb) 395 { 396 struct erofs_sb_info *sbi = EROFS_SB(sb); 397 struct erofs_buf buf = __EROFS_BUF_INITIALIZER; 398 unsigned int algs, alg; 399 erofs_off_t offset; 400 int size, ret = 0; 401 402 if (!erofs_sb_has_compr_cfgs(sbi)) { 403 sbi->available_compr_algs = 1 << Z_EROFS_COMPRESSION_LZ4; 404 return z_erofs_load_lz4_config(sb, dsb, NULL, 0); 405 } 406 407 sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs); 408 if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) { 409 erofs_err(sb, "unidentified algorithms %x, please upgrade kernel", 410 sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS); 411 return -EOPNOTSUPP; 412 } 413 414 erofs_init_metabuf(&buf, sb); 415 offset = EROFS_SUPER_OFFSET + sbi->sb_size; 416 alg = 0; 417 for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) { 418 void *data; 419 420 if (!(algs & 1)) 421 continue; 422 423 data = erofs_read_metadata(sb, &buf, &offset, &size); 424 if (IS_ERR(data)) { 425 ret = PTR_ERR(data); 426 break; 427 } 428 429 if (alg >= ARRAY_SIZE(erofs_decompressors) || 430 !erofs_decompressors[alg].config) { 431 erofs_err(sb, "algorithm %d isn't enabled on this kernel", 432 alg); 433 ret = -EOPNOTSUPP; 434 } else { 435 ret = erofs_decompressors[alg].config(sb, 436 dsb, data, size); 437 } 438 439 kfree(data); 440 if (ret) 441 break; 442 } 443 erofs_put_metabuf(&buf); 444 return ret; 445 } 446