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 static void scroll(void) 149 { 150 int i; 151 152 memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2); 153 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2) 154 vidmem[i] = ' '; 155 } 156 157 #define XMTRDY 0x20 158 159 #define TXR 0 /* Transmit register (WRITE) */ 160 #define LSR 5 /* Line Status */ 161 static void serial_putchar(int ch) 162 { 163 unsigned timeout = 0xffff; 164 165 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout) 166 cpu_relax(); 167 168 outb(ch, early_serial_base + TXR); 169 } 170 171 void __putstr(const char *s) 172 { 173 int x, y, pos; 174 char c; 175 176 if (early_serial_base) { 177 const char *str = s; 178 while (*str) { 179 if (*str == '\n') 180 serial_putchar('\r'); 181 serial_putchar(*str++); 182 } 183 } 184 185 if (real_mode->screen_info.orig_video_mode == 0 && 186 lines == 0 && cols == 0) 187 return; 188 189 x = real_mode->screen_info.orig_x; 190 y = real_mode->screen_info.orig_y; 191 192 while ((c = *s++) != '\0') { 193 if (c == '\n') { 194 x = 0; 195 if (++y >= lines) { 196 scroll(); 197 y--; 198 } 199 } else { 200 vidmem[(x + cols * y) * 2] = c; 201 if (++x >= cols) { 202 x = 0; 203 if (++y >= lines) { 204 scroll(); 205 y--; 206 } 207 } 208 } 209 } 210 211 real_mode->screen_info.orig_x = x; 212 real_mode->screen_info.orig_y = y; 213 214 pos = (x + cols * y) * 2; /* Update cursor position */ 215 outb(14, vidport); 216 outb(0xff & (pos >> 9), vidport+1); 217 outb(15, vidport); 218 outb(0xff & (pos >> 1), vidport+1); 219 } 220 221 void *memset(void *s, int c, size_t n) 222 { 223 int i; 224 char *ss = s; 225 226 for (i = 0; i < n; i++) 227 ss[i] = c; 228 return s; 229 } 230 #ifdef CONFIG_X86_32 231 void *memcpy(void *dest, const void *src, size_t n) 232 { 233 int d0, d1, d2; 234 asm volatile( 235 "rep ; movsl\n\t" 236 "movl %4,%%ecx\n\t" 237 "rep ; movsb\n\t" 238 : "=&c" (d0), "=&D" (d1), "=&S" (d2) 239 : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src) 240 : "memory"); 241 242 return dest; 243 } 244 #else 245 void *memcpy(void *dest, const void *src, size_t n) 246 { 247 long d0, d1, d2; 248 asm volatile( 249 "rep ; movsq\n\t" 250 "movq %4,%%rcx\n\t" 251 "rep ; movsb\n\t" 252 : "=&c" (d0), "=&D" (d1), "=&S" (d2) 253 : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src) 254 : "memory"); 255 256 return dest; 257 } 258 #endif 259 260 static void error(char *x) 261 { 262 error_putstr("\n\n"); 263 error_putstr(x); 264 error_putstr("\n\n -- System halted"); 265 266 while (1) 267 asm("hlt"); 268 } 269 270 static void parse_elf(void *output) 271 { 272 #ifdef CONFIG_X86_64 273 Elf64_Ehdr ehdr; 274 Elf64_Phdr *phdrs, *phdr; 275 #else 276 Elf32_Ehdr ehdr; 277 Elf32_Phdr *phdrs, *phdr; 278 #endif 279 void *dest; 280 int i; 281 282 memcpy(&ehdr, output, sizeof(ehdr)); 283 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 || 284 ehdr.e_ident[EI_MAG1] != ELFMAG1 || 285 ehdr.e_ident[EI_MAG2] != ELFMAG2 || 286 ehdr.e_ident[EI_MAG3] != ELFMAG3) { 287 error("Kernel is not a valid ELF file"); 288 return; 289 } 290 291 debug_putstr("Parsing ELF... "); 292 293 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum); 294 if (!phdrs) 295 error("Failed to allocate space for phdrs"); 296 297 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum); 298 299 for (i = 0; i < ehdr.e_phnum; i++) { 300 phdr = &phdrs[i]; 301 302 switch (phdr->p_type) { 303 case PT_LOAD: 304 #ifdef CONFIG_RELOCATABLE 305 dest = output; 306 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR); 307 #else 308 dest = (void *)(phdr->p_paddr); 309 #endif 310 memcpy(dest, 311 output + phdr->p_offset, 312 phdr->p_filesz); 313 break; 314 default: /* Ignore other PT_* */ break; 315 } 316 } 317 318 free(phdrs); 319 } 320 321 asmlinkage void decompress_kernel(void *rmode, memptr heap, 322 unsigned char *input_data, 323 unsigned long input_len, 324 unsigned char *output) 325 { 326 real_mode = rmode; 327 328 if (real_mode->screen_info.orig_video_mode == 7) { 329 vidmem = (char *) 0xb0000; 330 vidport = 0x3b4; 331 } else { 332 vidmem = (char *) 0xb8000; 333 vidport = 0x3d4; 334 } 335 336 lines = real_mode->screen_info.orig_video_lines; 337 cols = real_mode->screen_info.orig_video_cols; 338 339 console_init(); 340 debug_putstr("early console in decompress_kernel\n"); 341 342 free_mem_ptr = heap; /* Heap */ 343 free_mem_end_ptr = heap + BOOT_HEAP_SIZE; 344 345 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1)) 346 error("Destination address inappropriately aligned"); 347 #ifdef CONFIG_X86_64 348 if (heap > 0x3fffffffffffUL) 349 error("Destination address too large"); 350 #else 351 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff)) 352 error("Destination address too large"); 353 #endif 354 #ifndef CONFIG_RELOCATABLE 355 if ((unsigned long)output != LOAD_PHYSICAL_ADDR) 356 error("Wrong destination address"); 357 #endif 358 359 debug_putstr("\nDecompressing Linux... "); 360 decompress(input_data, input_len, NULL, NULL, output, NULL, error); 361 parse_elf(output); 362 debug_putstr("done.\nBooting the kernel.\n"); 363 return; 364 } 365