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 */ 111 112 void *memset(void *s, int c, size_t n); 113 void *memcpy(void *dest, const void *src, size_t n); 114 115 memptr free_mem_ptr; 116 memptr free_mem_end_ptr; 117 118 static char *vidmem; 119 static int vidport; 120 static int lines, cols; 121 122 #ifdef CONFIG_KERNEL_GZIP 123 #include "../../../../lib/decompress_inflate.c" 124 #endif 125 126 #ifdef CONFIG_KERNEL_BZIP2 127 #include "../../../../lib/decompress_bunzip2.c" 128 #endif 129 130 #ifdef CONFIG_KERNEL_LZMA 131 #include "../../../../lib/decompress_unlzma.c" 132 #endif 133 134 #ifdef CONFIG_KERNEL_XZ 135 #include "../../../../lib/decompress_unxz.c" 136 #endif 137 138 #ifdef CONFIG_KERNEL_LZO 139 #include "../../../../lib/decompress_unlzo.c" 140 #endif 141 142 #ifdef CONFIG_KERNEL_LZ4 143 #include "../../../../lib/decompress_unlz4.c" 144 #endif 145 146 static void scroll(void) 147 { 148 int i; 149 150 memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2); 151 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2) 152 vidmem[i] = ' '; 153 } 154 155 #define XMTRDY 0x20 156 157 #define TXR 0 /* Transmit register (WRITE) */ 158 #define LSR 5 /* Line Status */ 159 static void serial_putchar(int ch) 160 { 161 unsigned timeout = 0xffff; 162 163 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout) 164 cpu_relax(); 165 166 outb(ch, early_serial_base + TXR); 167 } 168 169 void __putstr(const char *s) 170 { 171 int x, y, pos; 172 char c; 173 174 if (early_serial_base) { 175 const char *str = s; 176 while (*str) { 177 if (*str == '\n') 178 serial_putchar('\r'); 179 serial_putchar(*str++); 180 } 181 } 182 183 if (real_mode->screen_info.orig_video_mode == 0 && 184 lines == 0 && cols == 0) 185 return; 186 187 x = real_mode->screen_info.orig_x; 188 y = real_mode->screen_info.orig_y; 189 190 while ((c = *s++) != '\0') { 191 if (c == '\n') { 192 x = 0; 193 if (++y >= lines) { 194 scroll(); 195 y--; 196 } 197 } else { 198 vidmem[(x + cols * y) * 2] = c; 199 if (++x >= cols) { 200 x = 0; 201 if (++y >= lines) { 202 scroll(); 203 y--; 204 } 205 } 206 } 207 } 208 209 real_mode->screen_info.orig_x = x; 210 real_mode->screen_info.orig_y = y; 211 212 pos = (x + cols * y) * 2; /* Update cursor position */ 213 outb(14, vidport); 214 outb(0xff & (pos >> 9), vidport+1); 215 outb(15, vidport); 216 outb(0xff & (pos >> 1), vidport+1); 217 } 218 219 void *memset(void *s, int c, size_t n) 220 { 221 int i; 222 char *ss = s; 223 224 for (i = 0; i < n; i++) 225 ss[i] = c; 226 return s; 227 } 228 #ifdef CONFIG_X86_32 229 void *memcpy(void *dest, const void *src, size_t n) 230 { 231 int d0, d1, d2; 232 asm volatile( 233 "rep ; movsl\n\t" 234 "movl %4,%%ecx\n\t" 235 "rep ; movsb\n\t" 236 : "=&c" (d0), "=&D" (d1), "=&S" (d2) 237 : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src) 238 : "memory"); 239 240 return dest; 241 } 242 #else 243 void *memcpy(void *dest, const void *src, size_t n) 244 { 245 long d0, d1, d2; 246 asm volatile( 247 "rep ; movsq\n\t" 248 "movq %4,%%rcx\n\t" 249 "rep ; movsb\n\t" 250 : "=&c" (d0), "=&D" (d1), "=&S" (d2) 251 : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src) 252 : "memory"); 253 254 return dest; 255 } 256 #endif 257 258 static void error(char *x) 259 { 260 error_putstr("\n\n"); 261 error_putstr(x); 262 error_putstr("\n\n -- System halted"); 263 264 while (1) 265 asm("hlt"); 266 } 267 268 #if CONFIG_X86_NEED_RELOCS 269 static void handle_relocations(void *output, unsigned long output_len) 270 { 271 int *reloc; 272 unsigned long delta, map, ptr; 273 unsigned long min_addr = (unsigned long)output; 274 unsigned long max_addr = min_addr + output_len; 275 276 /* 277 * Calculate the delta between where vmlinux was linked to load 278 * and where it was actually loaded. 279 */ 280 delta = min_addr - LOAD_PHYSICAL_ADDR; 281 if (!delta) { 282 debug_putstr("No relocation needed... "); 283 return; 284 } 285 debug_putstr("Performing relocations... "); 286 287 /* 288 * The kernel contains a table of relocation addresses. Those 289 * addresses have the final load address of the kernel in virtual 290 * memory. We are currently working in the self map. So we need to 291 * create an adjustment for kernel memory addresses to the self map. 292 * This will involve subtracting out the base address of the kernel. 293 */ 294 map = delta - __START_KERNEL_map; 295 296 /* 297 * Process relocations: 32 bit relocations first then 64 bit after. 298 * Two sets of binary relocations are added to the end of the kernel 299 * before compression. Each relocation table entry is the kernel 300 * address of the location which needs to be updated stored as a 301 * 32-bit value which is sign extended to 64 bits. 302 * 303 * Format is: 304 * 305 * kernel bits... 306 * 0 - zero terminator for 64 bit relocations 307 * 64 bit relocation repeated 308 * 0 - zero terminator for 32 bit relocations 309 * 32 bit relocation repeated 310 * 311 * So we work backwards from the end of the decompressed image. 312 */ 313 for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) { 314 int extended = *reloc; 315 extended += map; 316 317 ptr = (unsigned long)extended; 318 if (ptr < min_addr || ptr > max_addr) 319 error("32-bit relocation outside of kernel!\n"); 320 321 *(uint32_t *)ptr += delta; 322 } 323 #ifdef CONFIG_X86_64 324 for (reloc--; *reloc; reloc--) { 325 long extended = *reloc; 326 extended += map; 327 328 ptr = (unsigned long)extended; 329 if (ptr < min_addr || ptr > max_addr) 330 error("64-bit relocation outside of kernel!\n"); 331 332 *(uint64_t *)ptr += delta; 333 } 334 #endif 335 } 336 #else 337 static inline void handle_relocations(void *output, unsigned long output_len) 338 { } 339 #endif 340 341 static void parse_elf(void *output) 342 { 343 #ifdef CONFIG_X86_64 344 Elf64_Ehdr ehdr; 345 Elf64_Phdr *phdrs, *phdr; 346 #else 347 Elf32_Ehdr ehdr; 348 Elf32_Phdr *phdrs, *phdr; 349 #endif 350 void *dest; 351 int i; 352 353 memcpy(&ehdr, output, sizeof(ehdr)); 354 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 || 355 ehdr.e_ident[EI_MAG1] != ELFMAG1 || 356 ehdr.e_ident[EI_MAG2] != ELFMAG2 || 357 ehdr.e_ident[EI_MAG3] != ELFMAG3) { 358 error("Kernel is not a valid ELF file"); 359 return; 360 } 361 362 debug_putstr("Parsing ELF... "); 363 364 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum); 365 if (!phdrs) 366 error("Failed to allocate space for phdrs"); 367 368 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum); 369 370 for (i = 0; i < ehdr.e_phnum; i++) { 371 phdr = &phdrs[i]; 372 373 switch (phdr->p_type) { 374 case PT_LOAD: 375 #ifdef CONFIG_RELOCATABLE 376 dest = output; 377 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR); 378 #else 379 dest = (void *)(phdr->p_paddr); 380 #endif 381 memcpy(dest, 382 output + phdr->p_offset, 383 phdr->p_filesz); 384 break; 385 default: /* Ignore other PT_* */ break; 386 } 387 } 388 389 free(phdrs); 390 } 391 392 asmlinkage void *decompress_kernel(void *rmode, memptr heap, 393 unsigned char *input_data, 394 unsigned long input_len, 395 unsigned char *output, 396 unsigned long output_len) 397 { 398 real_mode = rmode; 399 400 sanitize_boot_params(real_mode); 401 402 if (real_mode->screen_info.orig_video_mode == 7) { 403 vidmem = (char *) 0xb0000; 404 vidport = 0x3b4; 405 } else { 406 vidmem = (char *) 0xb8000; 407 vidport = 0x3d4; 408 } 409 410 lines = real_mode->screen_info.orig_video_lines; 411 cols = real_mode->screen_info.orig_video_cols; 412 413 console_init(); 414 debug_putstr("early console in decompress_kernel\n"); 415 416 free_mem_ptr = heap; /* Heap */ 417 free_mem_end_ptr = heap + BOOT_HEAP_SIZE; 418 419 output = choose_kernel_location(input_data, input_len, 420 output, output_len); 421 422 /* Validate memory location choices. */ 423 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1)) 424 error("Destination address inappropriately aligned"); 425 #ifdef CONFIG_X86_64 426 if (heap > 0x3fffffffffffUL) 427 error("Destination address too large"); 428 #else 429 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff)) 430 error("Destination address too large"); 431 #endif 432 #ifndef CONFIG_RELOCATABLE 433 if ((unsigned long)output != LOAD_PHYSICAL_ADDR) 434 error("Wrong destination address"); 435 #endif 436 437 debug_putstr("\nDecompressing Linux... "); 438 decompress(input_data, input_len, NULL, NULL, output, NULL, error); 439 parse_elf(output); 440 handle_relocations(output, output_len); 441 debug_putstr("done.\nBooting the kernel.\n"); 442 return output; 443 } 444