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 #ifdef CONFIG_X86_64 116 #define memptr long 117 #else 118 #define memptr unsigned 119 #endif 120 121 static memptr free_mem_ptr; 122 static memptr free_mem_end_ptr; 123 124 static char *vidmem; 125 static int vidport; 126 static int lines, cols; 127 128 #ifdef CONFIG_KERNEL_GZIP 129 #include "../../../../lib/decompress_inflate.c" 130 #endif 131 132 #ifdef CONFIG_KERNEL_BZIP2 133 #include "../../../../lib/decompress_bunzip2.c" 134 #endif 135 136 #ifdef CONFIG_KERNEL_LZMA 137 #include "../../../../lib/decompress_unlzma.c" 138 #endif 139 140 #ifdef CONFIG_KERNEL_XZ 141 #include "../../../../lib/decompress_unxz.c" 142 #endif 143 144 #ifdef CONFIG_KERNEL_LZO 145 #include "../../../../lib/decompress_unlzo.c" 146 #endif 147 148 #ifdef CONFIG_KERNEL_LZ4 149 #include "../../../../lib/decompress_unlz4.c" 150 #endif 151 152 static void scroll(void) 153 { 154 int i; 155 156 memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2); 157 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2) 158 vidmem[i] = ' '; 159 } 160 161 #define XMTRDY 0x20 162 163 #define TXR 0 /* Transmit register (WRITE) */ 164 #define LSR 5 /* Line Status */ 165 static void serial_putchar(int ch) 166 { 167 unsigned timeout = 0xffff; 168 169 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout) 170 cpu_relax(); 171 172 outb(ch, early_serial_base + TXR); 173 } 174 175 void __putstr(const char *s) 176 { 177 int x, y, pos; 178 char c; 179 180 if (early_serial_base) { 181 const char *str = s; 182 while (*str) { 183 if (*str == '\n') 184 serial_putchar('\r'); 185 serial_putchar(*str++); 186 } 187 } 188 189 if (real_mode->screen_info.orig_video_mode == 0 && 190 lines == 0 && cols == 0) 191 return; 192 193 x = real_mode->screen_info.orig_x; 194 y = real_mode->screen_info.orig_y; 195 196 while ((c = *s++) != '\0') { 197 if (c == '\n') { 198 x = 0; 199 if (++y >= lines) { 200 scroll(); 201 y--; 202 } 203 } else { 204 vidmem[(x + cols * y) * 2] = c; 205 if (++x >= cols) { 206 x = 0; 207 if (++y >= lines) { 208 scroll(); 209 y--; 210 } 211 } 212 } 213 } 214 215 real_mode->screen_info.orig_x = x; 216 real_mode->screen_info.orig_y = y; 217 218 pos = (x + cols * y) * 2; /* Update cursor position */ 219 outb(14, vidport); 220 outb(0xff & (pos >> 9), vidport+1); 221 outb(15, vidport); 222 outb(0xff & (pos >> 1), vidport+1); 223 } 224 225 void *memset(void *s, int c, size_t n) 226 { 227 int i; 228 char *ss = s; 229 230 for (i = 0; i < n; i++) 231 ss[i] = c; 232 return s; 233 } 234 #ifdef CONFIG_X86_32 235 void *memcpy(void *dest, const void *src, size_t n) 236 { 237 int d0, d1, d2; 238 asm volatile( 239 "rep ; movsl\n\t" 240 "movl %4,%%ecx\n\t" 241 "rep ; movsb\n\t" 242 : "=&c" (d0), "=&D" (d1), "=&S" (d2) 243 : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src) 244 : "memory"); 245 246 return dest; 247 } 248 #else 249 void *memcpy(void *dest, const void *src, size_t n) 250 { 251 long d0, d1, d2; 252 asm volatile( 253 "rep ; movsq\n\t" 254 "movq %4,%%rcx\n\t" 255 "rep ; movsb\n\t" 256 : "=&c" (d0), "=&D" (d1), "=&S" (d2) 257 : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src) 258 : "memory"); 259 260 return dest; 261 } 262 #endif 263 264 static void error(char *x) 265 { 266 error_putstr("\n\n"); 267 error_putstr(x); 268 error_putstr("\n\n -- System halted"); 269 270 while (1) 271 asm("hlt"); 272 } 273 274 #if CONFIG_X86_NEED_RELOCS 275 static void handle_relocations(void *output, unsigned long output_len) 276 { 277 int *reloc; 278 unsigned long delta, map, ptr; 279 unsigned long min_addr = (unsigned long)output; 280 unsigned long max_addr = min_addr + output_len; 281 282 /* 283 * Calculate the delta between where vmlinux was linked to load 284 * and where it was actually loaded. 285 */ 286 delta = min_addr - LOAD_PHYSICAL_ADDR; 287 if (!delta) { 288 debug_putstr("No relocation needed... "); 289 return; 290 } 291 debug_putstr("Performing relocations... "); 292 293 /* 294 * The kernel contains a table of relocation addresses. Those 295 * addresses have the final load address of the kernel in virtual 296 * memory. We are currently working in the self map. So we need to 297 * create an adjustment for kernel memory addresses to the self map. 298 * This will involve subtracting out the base address of the kernel. 299 */ 300 map = delta - __START_KERNEL_map; 301 302 /* 303 * Process relocations: 32 bit relocations first then 64 bit after. 304 * Two sets of binary relocations are added to the end of the kernel 305 * before compression. Each relocation table entry is the kernel 306 * address of the location which needs to be updated stored as a 307 * 32-bit value which is sign extended to 64 bits. 308 * 309 * Format is: 310 * 311 * kernel bits... 312 * 0 - zero terminator for 64 bit relocations 313 * 64 bit relocation repeated 314 * 0 - zero terminator for 32 bit relocations 315 * 32 bit relocation repeated 316 * 317 * So we work backwards from the end of the decompressed image. 318 */ 319 for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) { 320 int extended = *reloc; 321 extended += map; 322 323 ptr = (unsigned long)extended; 324 if (ptr < min_addr || ptr > max_addr) 325 error("32-bit relocation outside of kernel!\n"); 326 327 *(uint32_t *)ptr += delta; 328 } 329 #ifdef CONFIG_X86_64 330 for (reloc--; *reloc; reloc--) { 331 long extended = *reloc; 332 extended += map; 333 334 ptr = (unsigned long)extended; 335 if (ptr < min_addr || ptr > max_addr) 336 error("64-bit relocation outside of kernel!\n"); 337 338 *(uint64_t *)ptr += delta; 339 } 340 #endif 341 } 342 #else 343 static inline void handle_relocations(void *output, unsigned long output_len) 344 { } 345 #endif 346 347 static void parse_elf(void *output) 348 { 349 #ifdef CONFIG_X86_64 350 Elf64_Ehdr ehdr; 351 Elf64_Phdr *phdrs, *phdr; 352 #else 353 Elf32_Ehdr ehdr; 354 Elf32_Phdr *phdrs, *phdr; 355 #endif 356 void *dest; 357 int i; 358 359 memcpy(&ehdr, output, sizeof(ehdr)); 360 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 || 361 ehdr.e_ident[EI_MAG1] != ELFMAG1 || 362 ehdr.e_ident[EI_MAG2] != ELFMAG2 || 363 ehdr.e_ident[EI_MAG3] != ELFMAG3) { 364 error("Kernel is not a valid ELF file"); 365 return; 366 } 367 368 debug_putstr("Parsing ELF... "); 369 370 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum); 371 if (!phdrs) 372 error("Failed to allocate space for phdrs"); 373 374 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum); 375 376 for (i = 0; i < ehdr.e_phnum; i++) { 377 phdr = &phdrs[i]; 378 379 switch (phdr->p_type) { 380 case PT_LOAD: 381 #ifdef CONFIG_RELOCATABLE 382 dest = output; 383 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR); 384 #else 385 dest = (void *)(phdr->p_paddr); 386 #endif 387 memcpy(dest, 388 output + phdr->p_offset, 389 phdr->p_filesz); 390 break; 391 default: /* Ignore other PT_* */ break; 392 } 393 } 394 395 free(phdrs); 396 } 397 398 asmlinkage void decompress_kernel(void *rmode, memptr heap, 399 unsigned char *input_data, 400 unsigned long input_len, 401 unsigned char *output, 402 unsigned long output_len) 403 { 404 real_mode = rmode; 405 406 sanitize_boot_params(real_mode); 407 408 if (real_mode->screen_info.orig_video_mode == 7) { 409 vidmem = (char *) 0xb0000; 410 vidport = 0x3b4; 411 } else { 412 vidmem = (char *) 0xb8000; 413 vidport = 0x3d4; 414 } 415 416 lines = real_mode->screen_info.orig_video_lines; 417 cols = real_mode->screen_info.orig_video_cols; 418 419 console_init(); 420 debug_putstr("early console in decompress_kernel\n"); 421 422 free_mem_ptr = heap; /* Heap */ 423 free_mem_end_ptr = heap + BOOT_HEAP_SIZE; 424 425 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1)) 426 error("Destination address inappropriately aligned"); 427 #ifdef CONFIG_X86_64 428 if (heap > 0x3fffffffffffUL) 429 error("Destination address too large"); 430 #else 431 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff)) 432 error("Destination address too large"); 433 #endif 434 #ifndef CONFIG_RELOCATABLE 435 if ((unsigned long)output != LOAD_PHYSICAL_ADDR) 436 error("Wrong destination address"); 437 #endif 438 439 debug_putstr("\nDecompressing Linux... "); 440 decompress(input_data, input_len, NULL, NULL, output, NULL, error); 441 parse_elf(output); 442 handle_relocations(output, output_len); 443 debug_putstr("done.\nBooting the kernel.\n"); 444 return; 445 } 446