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
lzo1x_1_do_compress(const unsigned char * in,size_t in_len,unsigned char * out,size_t * out_len,size_t ti,void * wrkmem,signed char * state_offset,const unsigned char bitstream_version)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 
lzogeneric1x_1_compress(const unsigned char * in,size_t in_len,unsigned char * out,size_t * out_len,void * wrkmem,const unsigned char bitstream_version)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 
lzo1x_1_compress(const unsigned char * in,size_t in_len,unsigned char * out,size_t * out_len,void * wrkmem)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 
lzorle1x_1_compress(const unsigned char * in,size_t in_len,unsigned char * out,size_t * out_len,void * wrkmem)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