1 /*
2 * misc.c
3 *
4 * This is a collection of several routines from gzip-1.0.3
5 * adapted for Linux.
6 *
7 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
8 * puts by Nick Holloway 1993, better puts by Martin Mares 1995
9 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
10 */
11
12 #include "misc.h"
13
14 /* WARNING!!
15 * This code is compiled with -fPIC and it is relocated dynamically
16 * at run time, but no relocation processing is performed.
17 * This means that it is not safe to place pointers in static structures.
18 */
19
20 /*
21 * Getting to provable safe in place decompression is hard.
22 * Worst case behaviours need to be analyzed.
23 * Background information:
24 *
25 * The file layout is:
26 * magic[2]
27 * method[1]
28 * flags[1]
29 * timestamp[4]
30 * extraflags[1]
31 * os[1]
32 * compressed data blocks[N]
33 * crc[4] orig_len[4]
34 *
35 * resulting in 18 bytes of non compressed data overhead.
36 *
37 * Files divided into blocks
38 * 1 bit (last block flag)
39 * 2 bits (block type)
40 *
41 * 1 block occurs every 32K -1 bytes or when there 50% compression
42 * has been achieved. The smallest block type encoding is always used.
43 *
44 * stored:
45 * 32 bits length in bytes.
46 *
47 * fixed:
48 * magic fixed tree.
49 * symbols.
50 *
51 * dynamic:
52 * dynamic tree encoding.
53 * symbols.
54 *
55 *
56 * The buffer for decompression in place is the length of the
57 * uncompressed data, plus a small amount extra to keep the algorithm safe.
58 * The compressed data is placed at the end of the buffer. The output
59 * pointer is placed at the start of the buffer and the input pointer
60 * is placed where the compressed data starts. Problems will occur
61 * when the output pointer overruns the input pointer.
62 *
63 * The output pointer can only overrun the input pointer if the input
64 * pointer is moving faster than the output pointer. A condition only
65 * triggered by data whose compressed form is larger than the uncompressed
66 * form.
67 *
68 * The worst case at the block level is a growth of the compressed data
69 * of 5 bytes per 32767 bytes.
70 *
71 * The worst case internal to a compressed block is very hard to figure.
72 * The worst case can at least be boundined by having one bit that represents
73 * 32764 bytes and then all of the rest of the bytes representing the very
74 * very last byte.
75 *
76 * All of which is enough to compute an amount of extra data that is required
77 * to be safe. To avoid problems at the block level allocating 5 extra bytes
78 * per 32767 bytes of data is sufficient. To avoind problems internal to a
79 * block adding an extra 32767 bytes (the worst case uncompressed block size)
80 * is sufficient, to ensure that in the worst case the decompressed data for
81 * block will stop the byte before the compressed data for a block begins.
82 * To avoid problems with the compressed data's meta information an extra 18
83 * bytes are needed. Leading to the formula:
84 *
85 * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
86 *
87 * Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
88 * Adding 32768 instead of 32767 just makes for round numbers.
89 * Adding the decompressor_size is necessary as it musht live after all
90 * of the data as well. Last I measured the decompressor is about 14K.
91 * 10K of actual data and 4K of bss.
92 *
93 */
94
95 /*
96 * gzip declarations
97 */
98 #define STATIC static
99
100 #undef memset
101 #undef memcpy
102 #define memzero(s, n) memset((s), 0, (n))
103
104
105 static void error(char *m);
106
107 /*
108 * This is set up by the setup-routine at boot-time
109 */
110 struct boot_params *real_mode; /* Pointer to real-mode data */
111 static int quiet;
112 static int debug;
113
114 void *memset(void *s, int c, size_t n);
115 void *memcpy(void *dest, const void *src, size_t n);
116
117 #ifdef CONFIG_X86_64
118 #define memptr long
119 #else
120 #define memptr unsigned
121 #endif
122
123 static memptr free_mem_ptr;
124 static memptr free_mem_end_ptr;
125
126 static char *vidmem;
127 static int vidport;
128 static int lines, cols;
129
130 #ifdef CONFIG_KERNEL_GZIP
131 #include "../../../../lib/decompress_inflate.c"
132 #endif
133
134 #ifdef CONFIG_KERNEL_BZIP2
135 #include "../../../../lib/decompress_bunzip2.c"
136 #endif
137
138 #ifdef CONFIG_KERNEL_LZMA
139 #include "../../../../lib/decompress_unlzma.c"
140 #endif
141
142 #ifdef CONFIG_KERNEL_XZ
143 #include "../../../../lib/decompress_unxz.c"
144 #endif
145
146 #ifdef CONFIG_KERNEL_LZO
147 #include "../../../../lib/decompress_unlzo.c"
148 #endif
149
scroll(void)150 static void scroll(void)
151 {
152 int i;
153
154 memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
155 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
156 vidmem[i] = ' ';
157 }
158
159 #define XMTRDY 0x20
160
161 #define TXR 0 /* Transmit register (WRITE) */
162 #define LSR 5 /* Line Status */
serial_putchar(int ch)163 static void serial_putchar(int ch)
164 {
165 unsigned timeout = 0xffff;
166
167 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
168 cpu_relax();
169
170 outb(ch, early_serial_base + TXR);
171 }
172
__putstr(int error,const char * s)173 void __putstr(int error, const char *s)
174 {
175 int x, y, pos;
176 char c;
177
178 #ifndef CONFIG_X86_VERBOSE_BOOTUP
179 if (!error)
180 return;
181 #endif
182 if (early_serial_base) {
183 const char *str = s;
184 while (*str) {
185 if (*str == '\n')
186 serial_putchar('\r');
187 serial_putchar(*str++);
188 }
189 }
190
191 if (real_mode->screen_info.orig_video_mode == 0 &&
192 lines == 0 && cols == 0)
193 return;
194
195 x = real_mode->screen_info.orig_x;
196 y = real_mode->screen_info.orig_y;
197
198 while ((c = *s++) != '\0') {
199 if (c == '\n') {
200 x = 0;
201 if (++y >= lines) {
202 scroll();
203 y--;
204 }
205 } else {
206 vidmem[(x + cols * y) * 2] = c;
207 if (++x >= cols) {
208 x = 0;
209 if (++y >= lines) {
210 scroll();
211 y--;
212 }
213 }
214 }
215 }
216
217 real_mode->screen_info.orig_x = x;
218 real_mode->screen_info.orig_y = y;
219
220 pos = (x + cols * y) * 2; /* Update cursor position */
221 outb(14, vidport);
222 outb(0xff & (pos >> 9), vidport+1);
223 outb(15, vidport);
224 outb(0xff & (pos >> 1), vidport+1);
225 }
226
memset(void * s,int c,size_t n)227 void *memset(void *s, int c, size_t n)
228 {
229 int i;
230 char *ss = s;
231
232 for (i = 0; i < n; i++)
233 ss[i] = c;
234 return s;
235 }
236 #ifdef CONFIG_X86_32
memcpy(void * dest,const void * src,size_t n)237 void *memcpy(void *dest, const void *src, size_t n)
238 {
239 int d0, d1, d2;
240 asm volatile(
241 "rep ; movsl\n\t"
242 "movl %4,%%ecx\n\t"
243 "rep ; movsb\n\t"
244 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
245 : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
246 : "memory");
247
248 return dest;
249 }
250 #else
memcpy(void * dest,const void * src,size_t n)251 void *memcpy(void *dest, const void *src, size_t n)
252 {
253 long d0, d1, d2;
254 asm volatile(
255 "rep ; movsq\n\t"
256 "movq %4,%%rcx\n\t"
257 "rep ; movsb\n\t"
258 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
259 : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
260 : "memory");
261
262 return dest;
263 }
264 #endif
265
error(char * x)266 static void error(char *x)
267 {
268 __putstr(1, "\n\n");
269 __putstr(1, x);
270 __putstr(1, "\n\n -- System halted");
271
272 while (1)
273 asm("hlt");
274 }
275
parse_elf(void * output)276 static void parse_elf(void *output)
277 {
278 #ifdef CONFIG_X86_64
279 Elf64_Ehdr ehdr;
280 Elf64_Phdr *phdrs, *phdr;
281 #else
282 Elf32_Ehdr ehdr;
283 Elf32_Phdr *phdrs, *phdr;
284 #endif
285 void *dest;
286 int i;
287
288 memcpy(&ehdr, output, sizeof(ehdr));
289 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
290 ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
291 ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
292 ehdr.e_ident[EI_MAG3] != ELFMAG3) {
293 error("Kernel is not a valid ELF file");
294 return;
295 }
296
297 if (!quiet)
298 putstr("Parsing ELF... ");
299
300 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
301 if (!phdrs)
302 error("Failed to allocate space for phdrs");
303
304 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
305
306 for (i = 0; i < ehdr.e_phnum; i++) {
307 phdr = &phdrs[i];
308
309 switch (phdr->p_type) {
310 case PT_LOAD:
311 #ifdef CONFIG_RELOCATABLE
312 dest = output;
313 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
314 #else
315 dest = (void *)(phdr->p_paddr);
316 #endif
317 memcpy(dest,
318 output + phdr->p_offset,
319 phdr->p_filesz);
320 break;
321 default: /* Ignore other PT_* */ break;
322 }
323 }
324 }
325
decompress_kernel(void * rmode,memptr heap,unsigned char * input_data,unsigned long input_len,unsigned char * output)326 asmlinkage void decompress_kernel(void *rmode, memptr heap,
327 unsigned char *input_data,
328 unsigned long input_len,
329 unsigned char *output)
330 {
331 real_mode = rmode;
332
333 if (cmdline_find_option_bool("quiet"))
334 quiet = 1;
335 if (cmdline_find_option_bool("debug"))
336 debug = 1;
337
338 if (real_mode->screen_info.orig_video_mode == 7) {
339 vidmem = (char *) 0xb0000;
340 vidport = 0x3b4;
341 } else {
342 vidmem = (char *) 0xb8000;
343 vidport = 0x3d4;
344 }
345
346 lines = real_mode->screen_info.orig_video_lines;
347 cols = real_mode->screen_info.orig_video_cols;
348
349 console_init();
350 if (debug)
351 putstr("early console in decompress_kernel\n");
352
353 free_mem_ptr = heap; /* Heap */
354 free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
355
356 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
357 error("Destination address inappropriately aligned");
358 #ifdef CONFIG_X86_64
359 if (heap > 0x3fffffffffffUL)
360 error("Destination address too large");
361 #else
362 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
363 error("Destination address too large");
364 #endif
365 #ifndef CONFIG_RELOCATABLE
366 if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
367 error("Wrong destination address");
368 #endif
369
370 if (!quiet)
371 putstr("\nDecompressing Linux... ");
372 decompress(input_data, input_len, NULL, NULL, output, NULL, error);
373 parse_elf(output);
374 if (!quiet)
375 putstr("done.\nBooting the kernel.\n");
376 return;
377 }
378