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 149 150 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 */ 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 } 172 173 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 } 226 227 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_32 237 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 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 265 266 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 } 275 276 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 } 325 326 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