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
21static noinline size_t
22lzo1x_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;
44literal:
45		ip += 1 + ((ip - ii) >> 5);
46next:
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 = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
54#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && \
55	defined(LZO_FAST_64BIT_MEMORY_ACCESS)
56			u64 dv64;
57
58			for (; (ir + 32) <= limit; ir += 32) {
59				dv64 = get_unaligned((u64 *)ir);
60				dv64 |= get_unaligned((u64 *)ir + 1);
61				dv64 |= get_unaligned((u64 *)ir + 2);
62				dv64 |= get_unaligned((u64 *)ir + 3);
63				if (dv64)
64					break;
65			}
66			for (; (ir + 8) <= limit; ir += 8) {
67				dv64 = get_unaligned((u64 *)ir);
68				if (dv64) {
69#  if defined(__LITTLE_ENDIAN)
70					ir += __builtin_ctzll(dv64) >> 3;
71#  elif defined(__BIG_ENDIAN)
72					ir += __builtin_clzll(dv64) >> 3;
73#  else
74#    error "missing endian definition"
75#  endif
76					break;
77				}
78			}
79#else
80			while ((ir < (const unsigned char *)
81					ALIGN((uintptr_t)ir, 4)) &&
82					(ir < limit) && (*ir == 0))
83				ir++;
84			if (IS_ALIGNED((uintptr_t)ir, 4)) {
85				for (; (ir + 4) <= limit; ir += 4) {
86					dv = *((u32 *)ir);
87					if (dv) {
88#  if defined(__LITTLE_ENDIAN)
89						ir += __builtin_ctz(dv) >> 3;
90#  elif defined(__BIG_ENDIAN)
91						ir += __builtin_clz(dv) >> 3;
92#  else
93#    error "missing endian definition"
94#  endif
95						break;
96					}
97				}
98			}
99#endif
100			while (likely(ir < limit) && unlikely(*ir == 0))
101				ir++;
102			run_length = ir - ip;
103			if (run_length > MAX_ZERO_RUN_LENGTH)
104				run_length = MAX_ZERO_RUN_LENGTH;
105		} else {
106			t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK;
107			m_pos = in + dict[t];
108			dict[t] = (lzo_dict_t) (ip - in);
109			if (unlikely(dv != get_unaligned_le32(m_pos)))
110				goto literal;
111		}
112
113		ii -= ti;
114		ti = 0;
115		t = ip - ii;
116		if (t != 0) {
117			if (t <= 3) {
118				op[*state_offset] |= t;
119				COPY4(op, ii);
120				op += t;
121			} else if (t <= 16) {
122				*op++ = (t - 3);
123				COPY8(op, ii);
124				COPY8(op + 8, ii + 8);
125				op += t;
126			} else {
127				if (t <= 18) {
128					*op++ = (t - 3);
129				} else {
130					size_t tt = t - 18;
131					*op++ = 0;
132					while (unlikely(tt > 255)) {
133						tt -= 255;
134						*op++ = 0;
135					}
136					*op++ = tt;
137				}
138				do {
139					COPY8(op, ii);
140					COPY8(op + 8, ii + 8);
141					op += 16;
142					ii += 16;
143					t -= 16;
144				} while (t >= 16);
145				if (t > 0) do {
146					*op++ = *ii++;
147				} while (--t > 0);
148			}
149		}
150
151		if (unlikely(run_length)) {
152			ip += run_length;
153			run_length -= MIN_ZERO_RUN_LENGTH;
154			put_unaligned_le32((run_length << 21) | 0xfffc18
155					   | (run_length & 0x7), op);
156			op += 4;
157			run_length = 0;
158			*state_offset = -3;
159			goto finished_writing_instruction;
160		}
161
162		m_len = 4;
163		{
164#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ64)
165		u64 v;
166		v = get_unaligned((const u64 *) (ip + m_len)) ^
167		    get_unaligned((const u64 *) (m_pos + m_len));
168		if (unlikely(v == 0)) {
169			do {
170				m_len += 8;
171				v = get_unaligned((const u64 *) (ip + m_len)) ^
172				    get_unaligned((const u64 *) (m_pos + m_len));
173				if (unlikely(ip + m_len >= ip_end))
174					goto m_len_done;
175			} while (v == 0);
176		}
177#  if defined(__LITTLE_ENDIAN)
178		m_len += (unsigned) __builtin_ctzll(v) / 8;
179#  elif defined(__BIG_ENDIAN)
180		m_len += (unsigned) __builtin_clzll(v) / 8;
181#  else
182#    error "missing endian definition"
183#  endif
184#elif defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ32)
185		u32 v;
186		v = get_unaligned((const u32 *) (ip + m_len)) ^
187		    get_unaligned((const u32 *) (m_pos + m_len));
188		if (unlikely(v == 0)) {
189			do {
190				m_len += 4;
191				v = get_unaligned((const u32 *) (ip + m_len)) ^
192				    get_unaligned((const u32 *) (m_pos + m_len));
193				if (v != 0)
194					break;
195				m_len += 4;
196				v = get_unaligned((const u32 *) (ip + m_len)) ^
197				    get_unaligned((const u32 *) (m_pos + m_len));
198				if (unlikely(ip + m_len >= ip_end))
199					goto m_len_done;
200			} while (v == 0);
201		}
202#  if defined(__LITTLE_ENDIAN)
203		m_len += (unsigned) __builtin_ctz(v) / 8;
204#  elif defined(__BIG_ENDIAN)
205		m_len += (unsigned) __builtin_clz(v) / 8;
206#  else
207#    error "missing endian definition"
208#  endif
209#else
210		if (unlikely(ip[m_len] == m_pos[m_len])) {
211			do {
212				m_len += 1;
213				if (ip[m_len] != m_pos[m_len])
214					break;
215				m_len += 1;
216				if (ip[m_len] != m_pos[m_len])
217					break;
218				m_len += 1;
219				if (ip[m_len] != m_pos[m_len])
220					break;
221				m_len += 1;
222				if (ip[m_len] != m_pos[m_len])
223					break;
224				m_len += 1;
225				if (ip[m_len] != m_pos[m_len])
226					break;
227				m_len += 1;
228				if (ip[m_len] != m_pos[m_len])
229					break;
230				m_len += 1;
231				if (ip[m_len] != m_pos[m_len])
232					break;
233				m_len += 1;
234				if (unlikely(ip + m_len >= ip_end))
235					goto m_len_done;
236			} while (ip[m_len] == m_pos[m_len]);
237		}
238#endif
239		}
240m_len_done:
241
242		m_off = ip - m_pos;
243		ip += m_len;
244		if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
245			m_off -= 1;
246			*op++ = (((m_len - 1) << 5) | ((m_off & 7) << 2));
247			*op++ = (m_off >> 3);
248		} else if (m_off <= M3_MAX_OFFSET) {
249			m_off -= 1;
250			if (m_len <= M3_MAX_LEN)
251				*op++ = (M3_MARKER | (m_len - 2));
252			else {
253				m_len -= M3_MAX_LEN;
254				*op++ = M3_MARKER | 0;
255				while (unlikely(m_len > 255)) {
256					m_len -= 255;
257					*op++ = 0;
258				}
259				*op++ = (m_len);
260			}
261			*op++ = (m_off << 2);
262			*op++ = (m_off >> 6);
263		} else {
264			m_off -= 0x4000;
265			if (m_len <= M4_MAX_LEN)
266				*op++ = (M4_MARKER | ((m_off >> 11) & 8)
267						| (m_len - 2));
268			else {
269				if (unlikely(((m_off & 0x403f) == 0x403f)
270						&& (m_len >= 261)
271						&& (m_len <= 264))
272						&& likely(bitstream_version)) {
273					// Under lzo-rle, block copies
274					// for 261 <= length <= 264 and
275					// (distance & 0x80f3) == 0x80f3
276					// can result in ambiguous
277					// output. Adjust length
278					// to 260 to prevent ambiguity.
279					ip -= m_len - 260;
280					m_len = 260;
281				}
282				m_len -= M4_MAX_LEN;
283				*op++ = (M4_MARKER | ((m_off >> 11) & 8));
284				while (unlikely(m_len > 255)) {
285					m_len -= 255;
286					*op++ = 0;
287				}
288				*op++ = (m_len);
289			}
290			*op++ = (m_off << 2);
291			*op++ = (m_off >> 6);
292		}
293		*state_offset = -2;
294finished_writing_instruction:
295		ii = ip;
296		goto next;
297	}
298	*out_len = op - out;
299	return in_end - (ii - ti);
300}
301
302static int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
303		     unsigned char *out, size_t *out_len,
304		     void *wrkmem, const unsigned char bitstream_version)
305{
306	const unsigned char *ip = in;
307	unsigned char *op = out;
308	unsigned char *data_start;
309	size_t l = in_len;
310	size_t t = 0;
311	signed char state_offset = -2;
312	unsigned int m4_max_offset;
313
314	// LZO v0 will never write 17 as first byte (except for zero-length
315	// input), so this is used to version the bitstream
316	if (bitstream_version > 0) {
317		*op++ = 17;
318		*op++ = bitstream_version;
319		m4_max_offset = M4_MAX_OFFSET_V1;
320	} else {
321		m4_max_offset = M4_MAX_OFFSET_V0;
322	}
323
324	data_start = op;
325
326	while (l > 20) {
327		size_t ll = min_t(size_t, l, m4_max_offset + 1);
328		uintptr_t ll_end = (uintptr_t) ip + ll;
329		if ((ll_end + ((t + ll) >> 5)) <= ll_end)
330			break;
331		BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS);
332		memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t));
333		t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem,
334					&state_offset, bitstream_version);
335		ip += ll;
336		op += *out_len;
337		l  -= ll;
338	}
339	t += l;
340
341	if (t > 0) {
342		const unsigned char *ii = in + in_len - t;
343
344		if (op == data_start && t <= 238) {
345			*op++ = (17 + t);
346		} else if (t <= 3) {
347			op[state_offset] |= t;
348		} else if (t <= 18) {
349			*op++ = (t - 3);
350		} else {
351			size_t tt = t - 18;
352			*op++ = 0;
353			while (tt > 255) {
354				tt -= 255;
355				*op++ = 0;
356			}
357			*op++ = tt;
358		}
359		if (t >= 16) do {
360			COPY8(op, ii);
361			COPY8(op + 8, ii + 8);
362			op += 16;
363			ii += 16;
364			t -= 16;
365		} while (t >= 16);
366		if (t > 0) do {
367			*op++ = *ii++;
368		} while (--t > 0);
369	}
370
371	*op++ = M4_MARKER | 1;
372	*op++ = 0;
373	*op++ = 0;
374
375	*out_len = op - out;
376	return LZO_E_OK;
377}
378
379int lzo1x_1_compress(const unsigned char *in, size_t in_len,
380		     unsigned char *out, size_t *out_len,
381		     void *wrkmem)
382{
383	return lzogeneric1x_1_compress(in, in_len, out, out_len, wrkmem, 0);
384}
385
386int lzorle1x_1_compress(const unsigned char *in, size_t in_len,
387		     unsigned char *out, size_t *out_len,
388		     void *wrkmem)
389{
390	return lzogeneric1x_1_compress(in, in_len, out, out_len,
391				       wrkmem, LZO_VERSION);
392}
393
394EXPORT_SYMBOL_GPL(lzo1x_1_compress);
395EXPORT_SYMBOL_GPL(lzorle1x_1_compress);
396
397MODULE_LICENSE("GPL");
398MODULE_DESCRIPTION("LZO1X-1 Compressor");
399