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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * 842 Software Compression4 *5 * Copyright (C) 2015 Dan Streetman, IBM Corp6 *7 * See 842.h for details of the 842 compressed format.8 */9 10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt11#define MODULE_NAME "842_compress"12 13#include <linux/hashtable.h>14 15#include "842.h"16#include "842_debugfs.h"17 18#define SW842_HASHTABLE8_BITS (10)19#define SW842_HASHTABLE4_BITS (11)20#define SW842_HASHTABLE2_BITS (10)21 22/* By default, we allow compressing input buffers of any length, but we must23 * use the non-standard "short data" template so the decompressor can correctly24 * reproduce the uncompressed data buffer at the right length. However the25 * hardware 842 compressor will not recognize the "short data" template, and26 * will fail to decompress any compressed buffer containing it (I have no idea27 * why anyone would want to use software to compress and hardware to decompress28 * but that's beside the point). This parameter forces the compression29 * function to simply reject any input buffer that isn't a multiple of 8 bytes30 * long, instead of using the "short data" template, so that all compressed31 * buffers produced by this function will be decompressable by the 842 hardware32 * decompressor. Unless you have a specific need for that, leave this disabled33 * so that any length buffer can be compressed.34 */35static bool sw842_strict;36module_param_named(strict, sw842_strict, bool, 0644);37 38static u8 comp_ops[OPS_MAX][5] = { /* params size in bits */39 { I8, N0, N0, N0, 0x19 }, /* 8 */40 { I4, I4, N0, N0, 0x18 }, /* 18 */41 { I4, I2, I2, N0, 0x17 }, /* 25 */42 { I2, I2, I4, N0, 0x13 }, /* 25 */43 { I2, I2, I2, I2, 0x12 }, /* 32 */44 { I4, I2, D2, N0, 0x16 }, /* 33 */45 { I4, D2, I2, N0, 0x15 }, /* 33 */46 { I2, D2, I4, N0, 0x0e }, /* 33 */47 { D2, I2, I4, N0, 0x09 }, /* 33 */48 { I2, I2, I2, D2, 0x11 }, /* 40 */49 { I2, I2, D2, I2, 0x10 }, /* 40 */50 { I2, D2, I2, I2, 0x0d }, /* 40 */51 { D2, I2, I2, I2, 0x08 }, /* 40 */52 { I4, D4, N0, N0, 0x14 }, /* 41 */53 { D4, I4, N0, N0, 0x04 }, /* 41 */54 { I2, I2, D4, N0, 0x0f }, /* 48 */55 { I2, D2, I2, D2, 0x0c }, /* 48 */56 { I2, D4, I2, N0, 0x0b }, /* 48 */57 { D2, I2, I2, D2, 0x07 }, /* 48 */58 { D2, I2, D2, I2, 0x06 }, /* 48 */59 { D4, I2, I2, N0, 0x03 }, /* 48 */60 { I2, D2, D4, N0, 0x0a }, /* 56 */61 { D2, I2, D4, N0, 0x05 }, /* 56 */62 { D4, I2, D2, N0, 0x02 }, /* 56 */63 { D4, D2, I2, N0, 0x01 }, /* 56 */64 { D8, N0, N0, N0, 0x00 }, /* 64 */65};66 67struct sw842_hlist_node8 {68 struct hlist_node node;69 u64 data;70 u8 index;71};72 73struct sw842_hlist_node4 {74 struct hlist_node node;75 u32 data;76 u16 index;77};78 79struct sw842_hlist_node2 {80 struct hlist_node node;81 u16 data;82 u8 index;83};84 85#define INDEX_NOT_FOUND (-1)86#define INDEX_NOT_CHECKED (-2)87 88struct sw842_param {89 u8 *in;90 u8 *instart;91 u64 ilen;92 u8 *out;93 u64 olen;94 u8 bit;95 u64 data8[1];96 u32 data4[2];97 u16 data2[4];98 int index8[1];99 int index4[2];100 int index2[4];101 DECLARE_HASHTABLE(htable8, SW842_HASHTABLE8_BITS);102 DECLARE_HASHTABLE(htable4, SW842_HASHTABLE4_BITS);103 DECLARE_HASHTABLE(htable2, SW842_HASHTABLE2_BITS);104 struct sw842_hlist_node8 node8[1 << I8_BITS];105 struct sw842_hlist_node4 node4[1 << I4_BITS];106 struct sw842_hlist_node2 node2[1 << I2_BITS];107};108 109#define get_input_data(p, o, b) \110 be##b##_to_cpu(get_unaligned((__be##b *)((p)->in + (o))))111 112#define init_hashtable_nodes(p, b) do { \113 int _i; \114 hash_init((p)->htable##b); \115 for (_i = 0; _i < ARRAY_SIZE((p)->node##b); _i++) { \116 (p)->node##b[_i].index = _i; \117 (p)->node##b[_i].data = 0; \118 INIT_HLIST_NODE(&(p)->node##b[_i].node); \119 } \120} while (0)121 122#define find_index(p, b, n) ({ \123 struct sw842_hlist_node##b *_n; \124 p->index##b[n] = INDEX_NOT_FOUND; \125 hash_for_each_possible(p->htable##b, _n, node, p->data##b[n]) { \126 if (p->data##b[n] == _n->data) { \127 p->index##b[n] = _n->index; \128 break; \129 } \130 } \131 p->index##b[n] >= 0; \132})133 134#define check_index(p, b, n) \135 ((p)->index##b[n] == INDEX_NOT_CHECKED \136 ? find_index(p, b, n) \137 : (p)->index##b[n] >= 0)138 139#define replace_hash(p, b, i, d) do { \140 struct sw842_hlist_node##b *_n = &(p)->node##b[(i)+(d)]; \141 hash_del(&_n->node); \142 _n->data = (p)->data##b[d]; \143 pr_debug("add hash index%x %x pos %x data %lx\n", b, \144 (unsigned int)_n->index, \145 (unsigned int)((p)->in - (p)->instart), \146 (unsigned long)_n->data); \147 hash_add((p)->htable##b, &_n->node, _n->data); \148} while (0)149 150static u8 bmask[8] = { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe };151 152static int add_bits(struct sw842_param *p, u64 d, u8 n);153 154static int __split_add_bits(struct sw842_param *p, u64 d, u8 n, u8 s)155{156 int ret;157 158 if (n <= s)159 return -EINVAL;160 161 ret = add_bits(p, d >> s, n - s);162 if (ret)163 return ret;164 return add_bits(p, d & GENMASK_ULL(s - 1, 0), s);165}166 167static int add_bits(struct sw842_param *p, u64 d, u8 n)168{169 int b = p->bit, bits = b + n, s = round_up(bits, 8) - bits;170 u64 o;171 u8 *out = p->out;172 173 pr_debug("add %u bits %lx\n", (unsigned char)n, (unsigned long)d);174 175 if (n > 64)176 return -EINVAL;177 178 /* split this up if writing to > 8 bytes (i.e. n == 64 && p->bit > 0),179 * or if we're at the end of the output buffer and would write past end180 */181 if (bits > 64)182 return __split_add_bits(p, d, n, 32);183 else if (p->olen < 8 && bits > 32 && bits <= 56)184 return __split_add_bits(p, d, n, 16);185 else if (p->olen < 4 && bits > 16 && bits <= 24)186 return __split_add_bits(p, d, n, 8);187 188 if (DIV_ROUND_UP(bits, 8) > p->olen)189 return -ENOSPC;190 191 o = *out & bmask[b];192 d <<= s;193 194 if (bits <= 8)195 *out = o | d;196 else if (bits <= 16)197 put_unaligned(cpu_to_be16(o << 8 | d), (__be16 *)out);198 else if (bits <= 24)199 put_unaligned(cpu_to_be32(o << 24 | d << 8), (__be32 *)out);200 else if (bits <= 32)201 put_unaligned(cpu_to_be32(o << 24 | d), (__be32 *)out);202 else if (bits <= 40)203 put_unaligned(cpu_to_be64(o << 56 | d << 24), (__be64 *)out);204 else if (bits <= 48)205 put_unaligned(cpu_to_be64(o << 56 | d << 16), (__be64 *)out);206 else if (bits <= 56)207 put_unaligned(cpu_to_be64(o << 56 | d << 8), (__be64 *)out);208 else209 put_unaligned(cpu_to_be64(o << 56 | d), (__be64 *)out);210 211 p->bit += n;212 213 if (p->bit > 7) {214 p->out += p->bit / 8;215 p->olen -= p->bit / 8;216 p->bit %= 8;217 }218 219 return 0;220}221 222static int add_template(struct sw842_param *p, u8 c)223{224 int ret, i, b = 0;225 u8 *t = comp_ops[c];226 bool inv = false;227 228 if (c >= OPS_MAX)229 return -EINVAL;230 231 pr_debug("template %x\n", t[4]);232 233 ret = add_bits(p, t[4], OP_BITS);234 if (ret)235 return ret;236 237 for (i = 0; i < 4; i++) {238 pr_debug("op %x\n", t[i]);239 240 switch (t[i] & OP_AMOUNT) {241 case OP_AMOUNT_8:242 if (b)243 inv = true;244 else if (t[i] & OP_ACTION_INDEX)245 ret = add_bits(p, p->index8[0], I8_BITS);246 else if (t[i] & OP_ACTION_DATA)247 ret = add_bits(p, p->data8[0], 64);248 else249 inv = true;250 break;251 case OP_AMOUNT_4:252 if (b == 2 && t[i] & OP_ACTION_DATA)253 ret = add_bits(p, get_input_data(p, 2, 32), 32);254 else if (b != 0 && b != 4)255 inv = true;256 else if (t[i] & OP_ACTION_INDEX)257 ret = add_bits(p, p->index4[b >> 2], I4_BITS);258 else if (t[i] & OP_ACTION_DATA)259 ret = add_bits(p, p->data4[b >> 2], 32);260 else261 inv = true;262 break;263 case OP_AMOUNT_2:264 if (b != 0 && b != 2 && b != 4 && b != 6)265 inv = true;266 if (t[i] & OP_ACTION_INDEX)267 ret = add_bits(p, p->index2[b >> 1], I2_BITS);268 else if (t[i] & OP_ACTION_DATA)269 ret = add_bits(p, p->data2[b >> 1], 16);270 else271 inv = true;272 break;273 case OP_AMOUNT_0:274 inv = (b != 8) || !(t[i] & OP_ACTION_NOOP);275 break;276 default:277 inv = true;278 break;279 }280 281 if (ret)282 return ret;283 284 if (inv) {285 pr_err("Invalid templ %x op %d : %x %x %x %x\n",286 c, i, t[0], t[1], t[2], t[3]);287 return -EINVAL;288 }289 290 b += t[i] & OP_AMOUNT;291 }292 293 if (b != 8) {294 pr_err("Invalid template %x len %x : %x %x %x %x\n",295 c, b, t[0], t[1], t[2], t[3]);296 return -EINVAL;297 }298 299 if (sw842_template_counts)300 atomic_inc(&template_count[t[4]]);301 302 return 0;303}304 305static int add_repeat_template(struct sw842_param *p, u8 r)306{307 int ret;308 309 /* repeat param is 0-based */310 if (!r || --r > REPEAT_BITS_MAX)311 return -EINVAL;312 313 ret = add_bits(p, OP_REPEAT, OP_BITS);314 if (ret)315 return ret;316 317 ret = add_bits(p, r, REPEAT_BITS);318 if (ret)319 return ret;320 321 if (sw842_template_counts)322 atomic_inc(&template_repeat_count);323 324 return 0;325}326 327static int add_short_data_template(struct sw842_param *p, u8 b)328{329 int ret, i;330 331 if (!b || b > SHORT_DATA_BITS_MAX)332 return -EINVAL;333 334 ret = add_bits(p, OP_SHORT_DATA, OP_BITS);335 if (ret)336 return ret;337 338 ret = add_bits(p, b, SHORT_DATA_BITS);339 if (ret)340 return ret;341 342 for (i = 0; i < b; i++) {343 ret = add_bits(p, p->in[i], 8);344 if (ret)345 return ret;346 }347 348 if (sw842_template_counts)349 atomic_inc(&template_short_data_count);350 351 return 0;352}353 354static int add_zeros_template(struct sw842_param *p)355{356 int ret = add_bits(p, OP_ZEROS, OP_BITS);357 358 if (ret)359 return ret;360 361 if (sw842_template_counts)362 atomic_inc(&template_zeros_count);363 364 return 0;365}366 367static int add_end_template(struct sw842_param *p)368{369 int ret = add_bits(p, OP_END, OP_BITS);370 371 if (ret)372 return ret;373 374 if (sw842_template_counts)375 atomic_inc(&template_end_count);376 377 return 0;378}379 380static bool check_template(struct sw842_param *p, u8 c)381{382 u8 *t = comp_ops[c];383 int i, match, b = 0;384 385 if (c >= OPS_MAX)386 return false;387 388 for (i = 0; i < 4; i++) {389 if (t[i] & OP_ACTION_INDEX) {390 if (t[i] & OP_AMOUNT_2)391 match = check_index(p, 2, b >> 1);392 else if (t[i] & OP_AMOUNT_4)393 match = check_index(p, 4, b >> 2);394 else if (t[i] & OP_AMOUNT_8)395 match = check_index(p, 8, 0);396 else397 return false;398 if (!match)399 return false;400 }401 402 b += t[i] & OP_AMOUNT;403 }404 405 return true;406}407 408static void get_next_data(struct sw842_param *p)409{410 p->data8[0] = get_input_data(p, 0, 64);411 p->data4[0] = get_input_data(p, 0, 32);412 p->data4[1] = get_input_data(p, 4, 32);413 p->data2[0] = get_input_data(p, 0, 16);414 p->data2[1] = get_input_data(p, 2, 16);415 p->data2[2] = get_input_data(p, 4, 16);416 p->data2[3] = get_input_data(p, 6, 16);417}418 419/* update the hashtable entries.420 * only call this after finding/adding the current template421 * the dataN fields for the current 8 byte block must be already updated422 */423static void update_hashtables(struct sw842_param *p)424{425 u64 pos = p->in - p->instart;426 u64 n8 = (pos >> 3) % (1 << I8_BITS);427 u64 n4 = (pos >> 2) % (1 << I4_BITS);428 u64 n2 = (pos >> 1) % (1 << I2_BITS);429 430 replace_hash(p, 8, n8, 0);431 replace_hash(p, 4, n4, 0);432 replace_hash(p, 4, n4, 1);433 replace_hash(p, 2, n2, 0);434 replace_hash(p, 2, n2, 1);435 replace_hash(p, 2, n2, 2);436 replace_hash(p, 2, n2, 3);437}438 439/* find the next template to use, and add it440 * the p->dataN fields must already be set for the current 8 byte block441 */442static int process_next(struct sw842_param *p)443{444 int ret, i;445 446 p->index8[0] = INDEX_NOT_CHECKED;447 p->index4[0] = INDEX_NOT_CHECKED;448 p->index4[1] = INDEX_NOT_CHECKED;449 p->index2[0] = INDEX_NOT_CHECKED;450 p->index2[1] = INDEX_NOT_CHECKED;451 p->index2[2] = INDEX_NOT_CHECKED;452 p->index2[3] = INDEX_NOT_CHECKED;453 454 /* check up to OPS_MAX - 1; last op is our fallback */455 for (i = 0; i < OPS_MAX - 1; i++) {456 if (check_template(p, i))457 break;458 }459 460 ret = add_template(p, i);461 if (ret)462 return ret;463 464 return 0;465}466 467/**468 * sw842_compress469 *470 * Compress the uncompressed buffer of length @ilen at @in to the output buffer471 * @out, using no more than @olen bytes, using the 842 compression format.472 *473 * Returns: 0 on success, error on failure. The @olen parameter474 * will contain the number of output bytes written on success, or475 * 0 on error.476 */477int sw842_compress(const u8 *in, unsigned int ilen,478 u8 *out, unsigned int *olen, void *wmem)479{480 struct sw842_param *p = (struct sw842_param *)wmem;481 int ret;482 u64 last, next, pad, total;483 u8 repeat_count = 0;484 u32 crc;485 486 BUILD_BUG_ON(sizeof(*p) > SW842_MEM_COMPRESS);487 488 init_hashtable_nodes(p, 8);489 init_hashtable_nodes(p, 4);490 init_hashtable_nodes(p, 2);491 492 p->in = (u8 *)in;493 p->instart = p->in;494 p->ilen = ilen;495 p->out = out;496 p->olen = *olen;497 p->bit = 0;498 499 total = p->olen;500 501 *olen = 0;502 503 /* if using strict mode, we can only compress a multiple of 8 */504 if (sw842_strict && (ilen % 8)) {505 pr_err("Using strict mode, can't compress len %d\n", ilen);506 return -EINVAL;507 }508 509 /* let's compress at least 8 bytes, mkay? */510 if (unlikely(ilen < 8))511 goto skip_comp;512 513 /* make initial 'last' different so we don't match the first time */514 last = ~get_unaligned((u64 *)p->in);515 516 while (p->ilen > 7) {517 next = get_unaligned((u64 *)p->in);518 519 /* must get the next data, as we need to update the hashtable520 * entries with the new data every time521 */522 get_next_data(p);523 524 /* we don't care about endianness in last or next;525 * we're just comparing 8 bytes to another 8 bytes,526 * they're both the same endianness527 */528 if (next == last) {529 /* repeat count bits are 0-based, so we stop at +1 */530 if (++repeat_count <= REPEAT_BITS_MAX)531 goto repeat;532 }533 if (repeat_count) {534 ret = add_repeat_template(p, repeat_count);535 repeat_count = 0;536 if (next == last) /* reached max repeat bits */537 goto repeat;538 }539 540 if (next == 0)541 ret = add_zeros_template(p);542 else543 ret = process_next(p);544 545 if (ret)546 return ret;547 548repeat:549 last = next;550 update_hashtables(p);551 p->in += 8;552 p->ilen -= 8;553 }554 555 if (repeat_count) {556 ret = add_repeat_template(p, repeat_count);557 if (ret)558 return ret;559 }560 561skip_comp:562 if (p->ilen > 0) {563 ret = add_short_data_template(p, p->ilen);564 if (ret)565 return ret;566 567 p->in += p->ilen;568 p->ilen = 0;569 }570 571 ret = add_end_template(p);572 if (ret)573 return ret;574 575 /*576 * crc(0:31) is appended to target data starting with the next577 * bit after End of stream template.578 * nx842 calculates CRC for data in big-endian format. So doing579 * same here so that sw842 decompression can be used for both580 * compressed data.581 */582 crc = crc32_be(0, in, ilen);583 ret = add_bits(p, crc, CRC_BITS);584 if (ret)585 return ret;586 587 if (p->bit) {588 p->out++;589 p->olen--;590 p->bit = 0;591 }592 593 /* pad compressed length to multiple of 8 */594 pad = (8 - ((total - p->olen) % 8)) % 8;595 if (pad) {596 if (pad > p->olen) /* we were so close! */597 return -ENOSPC;598 memset(p->out, 0, pad);599 p->out += pad;600 p->olen -= pad;601 }602 603 if (unlikely((total - p->olen) > UINT_MAX))604 return -ENOSPC;605 606 *olen = total - p->olen;607 608 return 0;609}610EXPORT_SYMBOL_GPL(sw842_compress);611 612static int __init sw842_init(void)613{614 if (sw842_template_counts)615 sw842_debugfs_create();616 617 return 0;618}619module_init(sw842_init);620 621static void __exit sw842_exit(void)622{623 if (sw842_template_counts)624 sw842_debugfs_remove();625}626module_exit(sw842_exit);627 628MODULE_LICENSE("GPL");629MODULE_DESCRIPTION("Software 842 Compressor");630MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");631