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2da572c9 DS |
1 | /* |
2 | * 842 Software Decompression | |
3 | * | |
4 | * Copyright (C) 2015 Dan Streetman, IBM Corp | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * See 842.h for details of the 842 compressed format. | |
17 | */ | |
18 | ||
19 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
20 | #define MODULE_NAME "842_decompress" | |
21 | ||
22 | #include "842.h" | |
23 | #include "842_debugfs.h" | |
24 | ||
25 | /* rolling fifo sizes */ | |
26 | #define I2_FIFO_SIZE (2 * (1 << I2_BITS)) | |
27 | #define I4_FIFO_SIZE (4 * (1 << I4_BITS)) | |
28 | #define I8_FIFO_SIZE (8 * (1 << I8_BITS)) | |
29 | ||
30 | static u8 decomp_ops[OPS_MAX][4] = { | |
31 | { D8, N0, N0, N0 }, | |
32 | { D4, D2, I2, N0 }, | |
33 | { D4, I2, D2, N0 }, | |
34 | { D4, I2, I2, N0 }, | |
35 | { D4, I4, N0, N0 }, | |
36 | { D2, I2, D4, N0 }, | |
37 | { D2, I2, D2, I2 }, | |
38 | { D2, I2, I2, D2 }, | |
39 | { D2, I2, I2, I2 }, | |
40 | { D2, I2, I4, N0 }, | |
41 | { I2, D2, D4, N0 }, | |
42 | { I2, D4, I2, N0 }, | |
43 | { I2, D2, I2, D2 }, | |
44 | { I2, D2, I2, I2 }, | |
45 | { I2, D2, I4, N0 }, | |
46 | { I2, I2, D4, N0 }, | |
47 | { I2, I2, D2, I2 }, | |
48 | { I2, I2, I2, D2 }, | |
49 | { I2, I2, I2, I2 }, | |
50 | { I2, I2, I4, N0 }, | |
51 | { I4, D4, N0, N0 }, | |
52 | { I4, D2, I2, N0 }, | |
53 | { I4, I2, D2, N0 }, | |
54 | { I4, I2, I2, N0 }, | |
55 | { I4, I4, N0, N0 }, | |
56 | { I8, N0, N0, N0 } | |
57 | }; | |
58 | ||
59 | struct sw842_param { | |
60 | u8 *in; | |
61 | u8 bit; | |
62 | u64 ilen; | |
63 | u8 *out; | |
64 | u8 *ostart; | |
65 | u64 olen; | |
66 | }; | |
67 | ||
68 | #define beN_to_cpu(d, s) \ | |
69 | ((s) == 2 ? be16_to_cpu(get_unaligned((__be16 *)d)) : \ | |
70 | (s) == 4 ? be32_to_cpu(get_unaligned((__be32 *)d)) : \ | |
71 | (s) == 8 ? be64_to_cpu(get_unaligned((__be64 *)d)) : \ | |
5ca636b9 | 72 | 0) |
2da572c9 DS |
73 | |
74 | static int next_bits(struct sw842_param *p, u64 *d, u8 n); | |
75 | ||
76 | static int __split_next_bits(struct sw842_param *p, u64 *d, u8 n, u8 s) | |
77 | { | |
78 | u64 tmp = 0; | |
79 | int ret; | |
80 | ||
81 | if (n <= s) { | |
82 | pr_debug("split_next_bits invalid n %u s %u\n", n, s); | |
83 | return -EINVAL; | |
84 | } | |
85 | ||
86 | ret = next_bits(p, &tmp, n - s); | |
87 | if (ret) | |
88 | return ret; | |
89 | ret = next_bits(p, d, s); | |
90 | if (ret) | |
91 | return ret; | |
92 | *d |= tmp << s; | |
93 | return 0; | |
94 | } | |
95 | ||
96 | static int next_bits(struct sw842_param *p, u64 *d, u8 n) | |
97 | { | |
98 | u8 *in = p->in, b = p->bit, bits = b + n; | |
99 | ||
100 | if (n > 64) { | |
101 | pr_debug("next_bits invalid n %u\n", n); | |
102 | return -EINVAL; | |
103 | } | |
104 | ||
105 | /* split this up if reading > 8 bytes, or if we're at the end of | |
106 | * the input buffer and would read past the end | |
107 | */ | |
108 | if (bits > 64) | |
109 | return __split_next_bits(p, d, n, 32); | |
110 | else if (p->ilen < 8 && bits > 32 && bits <= 56) | |
111 | return __split_next_bits(p, d, n, 16); | |
112 | else if (p->ilen < 4 && bits > 16 && bits <= 24) | |
113 | return __split_next_bits(p, d, n, 8); | |
114 | ||
115 | if (DIV_ROUND_UP(bits, 8) > p->ilen) | |
116 | return -EOVERFLOW; | |
117 | ||
118 | if (bits <= 8) | |
119 | *d = *in >> (8 - bits); | |
120 | else if (bits <= 16) | |
121 | *d = be16_to_cpu(get_unaligned((__be16 *)in)) >> (16 - bits); | |
122 | else if (bits <= 32) | |
123 | *d = be32_to_cpu(get_unaligned((__be32 *)in)) >> (32 - bits); | |
124 | else | |
125 | *d = be64_to_cpu(get_unaligned((__be64 *)in)) >> (64 - bits); | |
126 | ||
127 | *d &= GENMASK_ULL(n - 1, 0); | |
128 | ||
129 | p->bit += n; | |
130 | ||
131 | if (p->bit > 7) { | |
132 | p->in += p->bit / 8; | |
133 | p->ilen -= p->bit / 8; | |
134 | p->bit %= 8; | |
135 | } | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
140 | static int do_data(struct sw842_param *p, u8 n) | |
141 | { | |
142 | u64 v; | |
143 | int ret; | |
144 | ||
145 | if (n > p->olen) | |
146 | return -ENOSPC; | |
147 | ||
148 | ret = next_bits(p, &v, n * 8); | |
149 | if (ret) | |
150 | return ret; | |
151 | ||
152 | switch (n) { | |
153 | case 2: | |
154 | put_unaligned(cpu_to_be16((u16)v), (__be16 *)p->out); | |
155 | break; | |
156 | case 4: | |
157 | put_unaligned(cpu_to_be32((u32)v), (__be32 *)p->out); | |
158 | break; | |
159 | case 8: | |
160 | put_unaligned(cpu_to_be64((u64)v), (__be64 *)p->out); | |
161 | break; | |
162 | default: | |
163 | return -EINVAL; | |
164 | } | |
165 | ||
166 | p->out += n; | |
167 | p->olen -= n; | |
168 | ||
169 | return 0; | |
170 | } | |
171 | ||
172 | static int __do_index(struct sw842_param *p, u8 size, u8 bits, u64 fsize) | |
173 | { | |
174 | u64 index, offset, total = round_down(p->out - p->ostart, 8); | |
175 | int ret; | |
176 | ||
177 | ret = next_bits(p, &index, bits); | |
178 | if (ret) | |
179 | return ret; | |
180 | ||
181 | offset = index * size; | |
182 | ||
183 | /* a ring buffer of fsize is used; correct the offset */ | |
184 | if (total > fsize) { | |
185 | /* this is where the current fifo is */ | |
186 | u64 section = round_down(total, fsize); | |
187 | /* the current pos in the fifo */ | |
ca7fc7e9 | 188 | u64 pos = total - section; |
2da572c9 DS |
189 | |
190 | /* if the offset is past/at the pos, we need to | |
191 | * go back to the last fifo section | |
192 | */ | |
193 | if (offset >= pos) | |
194 | section -= fsize; | |
195 | ||
196 | offset += section; | |
197 | } | |
198 | ||
199 | if (offset + size > total) { | |
200 | pr_debug("index%x %lx points past end %lx\n", size, | |
201 | (unsigned long)offset, (unsigned long)total); | |
202 | return -EINVAL; | |
203 | } | |
204 | ||
5ca636b9 DS |
205 | if (size != 2 && size != 4 && size != 8) |
206 | WARN(1, "__do_index invalid size %x\n", size); | |
207 | else | |
208 | pr_debug("index%x to %lx off %lx adjoff %lx tot %lx data %lx\n", | |
209 | size, (unsigned long)index, | |
210 | (unsigned long)(index * size), (unsigned long)offset, | |
211 | (unsigned long)total, | |
212 | (unsigned long)beN_to_cpu(&p->ostart[offset], size)); | |
2da572c9 DS |
213 | |
214 | memcpy(p->out, &p->ostart[offset], size); | |
215 | p->out += size; | |
216 | p->olen -= size; | |
217 | ||
218 | return 0; | |
219 | } | |
220 | ||
f7ead7b4 | 221 | static int do_index(struct sw842_param *p, u8 n) |
2da572c9 DS |
222 | { |
223 | switch (n) { | |
224 | case 2: | |
225 | return __do_index(p, 2, I2_BITS, I2_FIFO_SIZE); | |
226 | case 4: | |
227 | return __do_index(p, 4, I4_BITS, I4_FIFO_SIZE); | |
228 | case 8: | |
229 | return __do_index(p, 8, I8_BITS, I8_FIFO_SIZE); | |
230 | default: | |
231 | return -EINVAL; | |
232 | } | |
233 | } | |
234 | ||
f7ead7b4 | 235 | static int do_op(struct sw842_param *p, u8 o) |
2da572c9 DS |
236 | { |
237 | int i, ret = 0; | |
238 | ||
239 | if (o >= OPS_MAX) | |
240 | return -EINVAL; | |
241 | ||
242 | for (i = 0; i < 4; i++) { | |
243 | u8 op = decomp_ops[o][i]; | |
244 | ||
245 | pr_debug("op is %x\n", op); | |
246 | ||
247 | switch (op & OP_ACTION) { | |
248 | case OP_ACTION_DATA: | |
249 | ret = do_data(p, op & OP_AMOUNT); | |
250 | break; | |
251 | case OP_ACTION_INDEX: | |
252 | ret = do_index(p, op & OP_AMOUNT); | |
253 | break; | |
254 | case OP_ACTION_NOOP: | |
255 | break; | |
256 | default: | |
fc4fa6e1 | 257 | pr_err("Internal error, invalid op %x\n", op); |
2da572c9 DS |
258 | return -EINVAL; |
259 | } | |
260 | ||
261 | if (ret) | |
262 | return ret; | |
263 | } | |
264 | ||
265 | if (sw842_template_counts) | |
266 | atomic_inc(&template_count[o]); | |
267 | ||
268 | return 0; | |
269 | } | |
270 | ||
271 | /** | |
272 | * sw842_decompress | |
273 | * | |
274 | * Decompress the 842-compressed buffer of length @ilen at @in | |
275 | * to the output buffer @out, using no more than @olen bytes. | |
276 | * | |
277 | * The compressed buffer must be only a single 842-compressed buffer, | |
278 | * with the standard format described in the comments in 842.h | |
279 | * Processing will stop when the 842 "END" template is detected, | |
280 | * not the end of the buffer. | |
281 | * | |
282 | * Returns: 0 on success, error on failure. The @olen parameter | |
283 | * will contain the number of output bytes written on success, or | |
284 | * 0 on error. | |
285 | */ | |
286 | int sw842_decompress(const u8 *in, unsigned int ilen, | |
287 | u8 *out, unsigned int *olen) | |
288 | { | |
289 | struct sw842_param p; | |
290 | int ret; | |
291 | u64 op, rep, tmp, bytes, total; | |
ea0b3984 | 292 | u64 crc; |
2da572c9 DS |
293 | |
294 | p.in = (u8 *)in; | |
295 | p.bit = 0; | |
296 | p.ilen = ilen; | |
297 | p.out = out; | |
298 | p.ostart = out; | |
299 | p.olen = *olen; | |
300 | ||
301 | total = p.olen; | |
302 | ||
303 | *olen = 0; | |
304 | ||
305 | do { | |
306 | ret = next_bits(&p, &op, OP_BITS); | |
307 | if (ret) | |
308 | return ret; | |
309 | ||
310 | pr_debug("template is %lx\n", (unsigned long)op); | |
311 | ||
312 | switch (op) { | |
313 | case OP_REPEAT: | |
314 | ret = next_bits(&p, &rep, REPEAT_BITS); | |
315 | if (ret) | |
316 | return ret; | |
317 | ||
318 | if (p.out == out) /* no previous bytes */ | |
319 | return -EINVAL; | |
320 | ||
321 | /* copy rep + 1 */ | |
322 | rep++; | |
323 | ||
324 | if (rep * 8 > p.olen) | |
325 | return -ENOSPC; | |
326 | ||
327 | while (rep-- > 0) { | |
328 | memcpy(p.out, p.out - 8, 8); | |
329 | p.out += 8; | |
330 | p.olen -= 8; | |
331 | } | |
332 | ||
333 | if (sw842_template_counts) | |
334 | atomic_inc(&template_repeat_count); | |
335 | ||
336 | break; | |
337 | case OP_ZEROS: | |
338 | if (8 > p.olen) | |
339 | return -ENOSPC; | |
340 | ||
341 | memset(p.out, 0, 8); | |
342 | p.out += 8; | |
343 | p.olen -= 8; | |
344 | ||
345 | if (sw842_template_counts) | |
346 | atomic_inc(&template_zeros_count); | |
347 | ||
348 | break; | |
349 | case OP_SHORT_DATA: | |
350 | ret = next_bits(&p, &bytes, SHORT_DATA_BITS); | |
351 | if (ret) | |
352 | return ret; | |
353 | ||
354 | if (!bytes || bytes > SHORT_DATA_BITS_MAX) | |
355 | return -EINVAL; | |
356 | ||
357 | while (bytes-- > 0) { | |
358 | ret = next_bits(&p, &tmp, 8); | |
359 | if (ret) | |
360 | return ret; | |
361 | *p.out = (u8)tmp; | |
362 | p.out++; | |
363 | p.olen--; | |
364 | } | |
365 | ||
366 | if (sw842_template_counts) | |
367 | atomic_inc(&template_short_data_count); | |
368 | ||
369 | break; | |
370 | case OP_END: | |
371 | if (sw842_template_counts) | |
372 | atomic_inc(&template_end_count); | |
373 | ||
374 | break; | |
375 | default: /* use template */ | |
376 | ret = do_op(&p, op); | |
377 | if (ret) | |
378 | return ret; | |
379 | break; | |
380 | } | |
381 | } while (op != OP_END); | |
382 | ||
ea0b3984 HM |
383 | /* |
384 | * crc(0:31) is saved in compressed data starting with the | |
385 | * next bit after End of stream template. | |
386 | */ | |
387 | ret = next_bits(&p, &crc, CRC_BITS); | |
388 | if (ret) | |
389 | return ret; | |
390 | ||
391 | /* | |
392 | * Validate CRC saved in compressed data. | |
393 | */ | |
394 | if (crc != (u64)crc32_be(0, out, total - p.olen)) { | |
395 | pr_debug("CRC mismatch for decompression\n"); | |
396 | return -EINVAL; | |
397 | } | |
398 | ||
2da572c9 DS |
399 | if (unlikely((total - p.olen) > UINT_MAX)) |
400 | return -ENOSPC; | |
401 | ||
402 | *olen = total - p.olen; | |
403 | ||
404 | return 0; | |
405 | } | |
406 | EXPORT_SYMBOL_GPL(sw842_decompress); | |
407 | ||
408 | static int __init sw842_init(void) | |
409 | { | |
410 | if (sw842_template_counts) | |
411 | sw842_debugfs_create(); | |
412 | ||
413 | return 0; | |
414 | } | |
415 | module_init(sw842_init); | |
416 | ||
417 | static void __exit sw842_exit(void) | |
418 | { | |
419 | if (sw842_template_counts) | |
420 | sw842_debugfs_remove(); | |
421 | } | |
422 | module_exit(sw842_exit); | |
423 | ||
424 | MODULE_LICENSE("GPL"); | |
425 | MODULE_DESCRIPTION("Software 842 Decompressor"); | |
426 | MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>"); |