1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * LZO1X Compressor from LZO 4 * 5 * Copyright (C) 1996-2012 Markus F.X.J. Oberhumer <markus@oberhumer.com> 6 * 7 * The full LZO package can be found at: 8 * http://www.oberhumer.com/opensource/lzo/ 9 * 10 * Changed for Linux kernel use by: 11 * Nitin Gupta <nitingupta910@gmail.com> 12 * Richard Purdie <rpurdie@openedhand.com> 13 */ 14 15 #include <linux/module.h> 16 #include <linux/kernel.h> 17 #include <asm/unaligned.h> 18 #include <linux/lzo.h> 19 #include "lzodefs.h" 20 21 static noinline size_t 22 lzo1x_1_do_compress(const unsigned char *in, size_t in_len, 23 unsigned char *out, size_t *out_len, 24 size_t ti, void *wrkmem, signed char *state_offset, 25 const unsigned char bitstream_version) 26 { 27 const unsigned char *ip; 28 unsigned char *op; 29 const unsigned char * const in_end = in + in_len; 30 const unsigned char * const ip_end = in + in_len - 20; 31 const unsigned char *ii; 32 lzo_dict_t * const dict = (lzo_dict_t *) wrkmem; 33 34 op = out; 35 ip = in; 36 ii = ip; 37 ip += ti < 4 ? 4 - ti : 0; 38 39 for (;;) { 40 const unsigned char *m_pos = NULL; 41 size_t t, m_len, m_off; 42 u32 dv; 43 u32 run_length = 0; 44 literal: 45 ip += 1 + ((ip - ii) >> 5); 46 next: 47 if (unlikely(ip >= ip_end)) 48 break; 49 dv = get_unaligned_le32(ip); 50 51 if (dv == 0 && bitstream_version) { 52 const unsigned char *ir = ip + 4; 53 const unsigned char *limit = ip_end 54 < (ip + MAX_ZERO_RUN_LENGTH + 1) 55 ? ip_end : ip + MAX_ZERO_RUN_LENGTH + 1; 56 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && \ 57 defined(LZO_FAST_64BIT_MEMORY_ACCESS) 58 u64 dv64; 59 60 for (; (ir + 32) <= limit; ir += 32) { 61 dv64 = get_unaligned((u64 *)ir); 62 dv64 |= get_unaligned((u64 *)ir + 1); 63 dv64 |= get_unaligned((u64 *)ir + 2); 64 dv64 |= get_unaligned((u64 *)ir + 3); 65 if (dv64) 66 break; 67 } 68 for (; (ir + 8) <= limit; ir += 8) { 69 dv64 = get_unaligned((u64 *)ir); 70 if (dv64) { 71 # if defined(__LITTLE_ENDIAN) 72 ir += __builtin_ctzll(dv64) >> 3; 73 # elif defined(__BIG_ENDIAN) 74 ir += __builtin_clzll(dv64) >> 3; 75 # else 76 # error "missing endian definition" 77 # endif 78 break; 79 } 80 } 81 #else 82 while ((ir < (const unsigned char *) 83 ALIGN((uintptr_t)ir, 4)) && 84 (ir < limit) && (*ir == 0)) 85 ir++; 86 if (IS_ALIGNED((uintptr_t)ir, 4)) { 87 for (; (ir + 4) <= limit; ir += 4) { 88 dv = *((u32 *)ir); 89 if (dv) { 90 # if defined(__LITTLE_ENDIAN) 91 ir += __builtin_ctz(dv) >> 3; 92 # elif defined(__BIG_ENDIAN) 93 ir += __builtin_clz(dv) >> 3; 94 # else 95 # error "missing endian definition" 96 # endif 97 break; 98 } 99 } 100 } 101 #endif 102 while (likely(ir < limit) && unlikely(*ir == 0)) 103 ir++; 104 run_length = ir - ip; 105 if (run_length > MAX_ZERO_RUN_LENGTH) 106 run_length = MAX_ZERO_RUN_LENGTH; 107 } else { 108 t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK; 109 m_pos = in + dict[t]; 110 dict[t] = (lzo_dict_t) (ip - in); 111 if (unlikely(dv != get_unaligned_le32(m_pos))) 112 goto literal; 113 } 114 115 ii -= ti; 116 ti = 0; 117 t = ip - ii; 118 if (t != 0) { 119 if (t <= 3) { 120 op[*state_offset] |= t; 121 COPY4(op, ii); 122 op += t; 123 } else if (t <= 16) { 124 *op++ = (t - 3); 125 COPY8(op, ii); 126 COPY8(op + 8, ii + 8); 127 op += t; 128 } else { 129 if (t <= 18) { 130 *op++ = (t - 3); 131 } else { 132 size_t tt = t - 18; 133 *op++ = 0; 134 while (unlikely(tt > 255)) { 135 tt -= 255; 136 *op++ = 0; 137 } 138 *op++ = tt; 139 } 140 do { 141 COPY8(op, ii); 142 COPY8(op + 8, ii + 8); 143 op += 16; 144 ii += 16; 145 t -= 16; 146 } while (t >= 16); 147 if (t > 0) do { 148 *op++ = *ii++; 149 } while (--t > 0); 150 } 151 } 152 153 if (unlikely(run_length)) { 154 ip += run_length; 155 run_length -= MIN_ZERO_RUN_LENGTH; 156 put_unaligned_le32((run_length << 21) | 0xfffc18 157 | (run_length & 0x7), op); 158 op += 4; 159 run_length = 0; 160 *state_offset = -3; 161 goto finished_writing_instruction; 162 } 163 164 m_len = 4; 165 { 166 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ64) 167 u64 v; 168 v = get_unaligned((const u64 *) (ip + m_len)) ^ 169 get_unaligned((const u64 *) (m_pos + m_len)); 170 if (unlikely(v == 0)) { 171 do { 172 m_len += 8; 173 v = get_unaligned((const u64 *) (ip + m_len)) ^ 174 get_unaligned((const u64 *) (m_pos + m_len)); 175 if (unlikely(ip + m_len >= ip_end)) 176 goto m_len_done; 177 } while (v == 0); 178 } 179 # if defined(__LITTLE_ENDIAN) 180 m_len += (unsigned) __builtin_ctzll(v) / 8; 181 # elif defined(__BIG_ENDIAN) 182 m_len += (unsigned) __builtin_clzll(v) / 8; 183 # else 184 # error "missing endian definition" 185 # endif 186 #elif defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ32) 187 u32 v; 188 v = get_unaligned((const u32 *) (ip + m_len)) ^ 189 get_unaligned((const u32 *) (m_pos + m_len)); 190 if (unlikely(v == 0)) { 191 do { 192 m_len += 4; 193 v = get_unaligned((const u32 *) (ip + m_len)) ^ 194 get_unaligned((const u32 *) (m_pos + m_len)); 195 if (v != 0) 196 break; 197 m_len += 4; 198 v = get_unaligned((const u32 *) (ip + m_len)) ^ 199 get_unaligned((const u32 *) (m_pos + m_len)); 200 if (unlikely(ip + m_len >= ip_end)) 201 goto m_len_done; 202 } while (v == 0); 203 } 204 # if defined(__LITTLE_ENDIAN) 205 m_len += (unsigned) __builtin_ctz(v) / 8; 206 # elif defined(__BIG_ENDIAN) 207 m_len += (unsigned) __builtin_clz(v) / 8; 208 # else 209 # error "missing endian definition" 210 # endif 211 #else 212 if (unlikely(ip[m_len] == m_pos[m_len])) { 213 do { 214 m_len += 1; 215 if (ip[m_len] != m_pos[m_len]) 216 break; 217 m_len += 1; 218 if (ip[m_len] != m_pos[m_len]) 219 break; 220 m_len += 1; 221 if (ip[m_len] != m_pos[m_len]) 222 break; 223 m_len += 1; 224 if (ip[m_len] != m_pos[m_len]) 225 break; 226 m_len += 1; 227 if (ip[m_len] != m_pos[m_len]) 228 break; 229 m_len += 1; 230 if (ip[m_len] != m_pos[m_len]) 231 break; 232 m_len += 1; 233 if (ip[m_len] != m_pos[m_len]) 234 break; 235 m_len += 1; 236 if (unlikely(ip + m_len >= ip_end)) 237 goto m_len_done; 238 } while (ip[m_len] == m_pos[m_len]); 239 } 240 #endif 241 } 242 m_len_done: 243 244 m_off = ip - m_pos; 245 ip += m_len; 246 if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) { 247 m_off -= 1; 248 *op++ = (((m_len - 1) << 5) | ((m_off & 7) << 2)); 249 *op++ = (m_off >> 3); 250 } else if (m_off <= M3_MAX_OFFSET) { 251 m_off -= 1; 252 if (m_len <= M3_MAX_LEN) 253 *op++ = (M3_MARKER | (m_len - 2)); 254 else { 255 m_len -= M3_MAX_LEN; 256 *op++ = M3_MARKER | 0; 257 while (unlikely(m_len > 255)) { 258 m_len -= 255; 259 *op++ = 0; 260 } 261 *op++ = (m_len); 262 } 263 *op++ = (m_off << 2); 264 *op++ = (m_off >> 6); 265 } else { 266 m_off -= 0x4000; 267 if (m_len <= M4_MAX_LEN) 268 *op++ = (M4_MARKER | ((m_off >> 11) & 8) 269 | (m_len - 2)); 270 else { 271 if (unlikely(((m_off & 0x403f) == 0x403f) 272 && (m_len >= 261) 273 && (m_len <= 264)) 274 && likely(bitstream_version)) { 275 // Under lzo-rle, block copies 276 // for 261 <= length <= 264 and 277 // (distance & 0x80f3) == 0x80f3 278 // can result in ambiguous 279 // output. Adjust length 280 // to 260 to prevent ambiguity. 281 ip -= m_len - 260; 282 m_len = 260; 283 } 284 m_len -= M4_MAX_LEN; 285 *op++ = (M4_MARKER | ((m_off >> 11) & 8)); 286 while (unlikely(m_len > 255)) { 287 m_len -= 255; 288 *op++ = 0; 289 } 290 *op++ = (m_len); 291 } 292 *op++ = (m_off << 2); 293 *op++ = (m_off >> 6); 294 } 295 *state_offset = -2; 296 finished_writing_instruction: 297 ii = ip; 298 goto next; 299 } 300 *out_len = op - out; 301 return in_end - (ii - ti); 302 } 303 304 static int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len, 305 unsigned char *out, size_t *out_len, 306 void *wrkmem, const unsigned char bitstream_version) 307 { 308 const unsigned char *ip = in; 309 unsigned char *op = out; 310 unsigned char *data_start; 311 size_t l = in_len; 312 size_t t = 0; 313 signed char state_offset = -2; 314 unsigned int m4_max_offset; 315 316 // LZO v0 will never write 17 as first byte (except for zero-length 317 // input), so this is used to version the bitstream 318 if (bitstream_version > 0) { 319 *op++ = 17; 320 *op++ = bitstream_version; 321 m4_max_offset = M4_MAX_OFFSET_V1; 322 } else { 323 m4_max_offset = M4_MAX_OFFSET_V0; 324 } 325 326 data_start = op; 327 328 while (l > 20) { 329 size_t ll = l <= (m4_max_offset + 1) ? l : (m4_max_offset + 1); 330 uintptr_t ll_end = (uintptr_t) ip + ll; 331 if ((ll_end + ((t + ll) >> 5)) <= ll_end) 332 break; 333 BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS); 334 memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t)); 335 t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem, 336 &state_offset, bitstream_version); 337 ip += ll; 338 op += *out_len; 339 l -= ll; 340 } 341 t += l; 342 343 if (t > 0) { 344 const unsigned char *ii = in + in_len - t; 345 346 if (op == data_start && t <= 238) { 347 *op++ = (17 + t); 348 } else if (t <= 3) { 349 op[state_offset] |= t; 350 } else if (t <= 18) { 351 *op++ = (t - 3); 352 } else { 353 size_t tt = t - 18; 354 *op++ = 0; 355 while (tt > 255) { 356 tt -= 255; 357 *op++ = 0; 358 } 359 *op++ = tt; 360 } 361 if (t >= 16) do { 362 COPY8(op, ii); 363 COPY8(op + 8, ii + 8); 364 op += 16; 365 ii += 16; 366 t -= 16; 367 } while (t >= 16); 368 if (t > 0) do { 369 *op++ = *ii++; 370 } while (--t > 0); 371 } 372 373 *op++ = M4_MARKER | 1; 374 *op++ = 0; 375 *op++ = 0; 376 377 *out_len = op - out; 378 return LZO_E_OK; 379 } 380 381 int lzo1x_1_compress(const unsigned char *in, size_t in_len, 382 unsigned char *out, size_t *out_len, 383 void *wrkmem) 384 { 385 return lzogeneric1x_1_compress(in, in_len, out, out_len, wrkmem, 0); 386 } 387 388 int lzorle1x_1_compress(const unsigned char *in, size_t in_len, 389 unsigned char *out, size_t *out_len, 390 void *wrkmem) 391 { 392 return lzogeneric1x_1_compress(in, in_len, out, out_len, 393 wrkmem, LZO_VERSION); 394 } 395 396 EXPORT_SYMBOL_GPL(lzo1x_1_compress); 397 EXPORT_SYMBOL_GPL(lzorle1x_1_compress); 398 399 MODULE_LICENSE("GPL"); 400 MODULE_DESCRIPTION("LZO1X-1 Compressor"); 401