arch/x86/boot/compressed/misc.c

   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 /*
  13  * we have to be careful, because no indirections are allowed here, and
  14  * paravirt_ops is a kind of one. As it will only run in baremetal anyway,
  15  * we just keep it from happening
  16  */
  17 #undef CONFIG_PARAVIRT
  18 #ifdef CONFIG_X86_32
  19 #define _ASM_DESC_H_ 1
  20 #endif
  21
  22 #ifdef CONFIG_X86_64
  23 #define _LINUX_STRING_H_ 1
  24 #define __LINUX_BITMAP_H 1
  25 #endif
  26
  27 #include <linux/linkage.h>
  28 #include <linux/screen_info.h>
  29 #include <linux/elf.h>
  30 #include <asm/io.h>
  31 #include <asm/page.h>
  32 #include <asm/boot.h>
  33
  34 /* WARNING!!
  35  * This code is compiled with -fPIC and it is relocated dynamically
  36  * at run time, but no relocation processing is performed.
  37  * This means that it is not safe to place pointers in static structures.
  38  */
  39
  40 /*
  41  * Getting to provable safe in place decompression is hard.
  42  * Worst case behaviours need to be analyzed.
  43  * Background information:
  44  *
  45  * The file layout is:
  46  *    magic[2]
  47  *    method[1]
  48  *    flags[1]
  49  *    timestamp[4]
  50  *    extraflags[1]
  51  *    os[1]
  52  *    compressed data blocks[N]
  53  *    crc[4] orig_len[4]
  54  *
  55  * resulting in 18 bytes of non compressed data overhead.
  56  *
  57  * Files divided into blocks
  58  * 1 bit (last block flag)
  59  * 2 bits (block type)
  60  *
  61  * 1 block occurs every 32K -1 bytes or when there 50% compression has been achieved.
  62  * The smallest block type encoding is always used.
  63  *
  64  * stored:
  65  *    32 bits length in bytes.
  66  *
  67  * fixed:
  68  *    magic fixed tree.
  69  *    symbols.
  70  *
  71  * dynamic:
  72  *    dynamic tree encoding.
  73  *    symbols.
  74  *
  75  *
  76  * The buffer for decompression in place is the length of the
  77  * uncompressed data, plus a small amount extra to keep the algorithm safe.
  78  * The compressed data is placed at the end of the buffer.  The output
  79  * pointer is placed at the start of the buffer and the input pointer
  80  * is placed where the compressed data starts.  Problems will occur
  81  * when the output pointer overruns the input pointer.
  82  *
  83  * The output pointer can only overrun the input pointer if the input
  84  * pointer is moving faster than the output pointer.  A condition only
  85  * triggered by data whose compressed form is larger than the uncompressed
  86  * form.
  87  *
  88  * The worst case at the block level is a growth of the compressed data
  89  * of 5 bytes per 32767 bytes.
  90  *
  91  * The worst case internal to a compressed block is very hard to figure.
  92  * The worst case can at least be boundined by having one bit that represents
  93  * 32764 bytes and then all of the rest of the bytes representing the very
  94  * very last byte.
  95  *
  96  * All of which is enough to compute an amount of extra data that is required
  97  * to be safe.  To avoid problems at the block level allocating 5 extra bytes
  98  * per 32767 bytes of data is sufficient.  To avoind problems internal to a block
  99  * adding an extra 32767 bytes (the worst case uncompressed block size) is
 100  * sufficient, to ensure that in the worst case the decompressed data for
 101  * block will stop the byte before the compressed data for a block begins.
 102  * To avoid problems with the compressed data's meta information an extra 18
 103  * bytes are needed.  Leading to the formula:
 104  *
 105  * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
 106  *
 107  * Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
 108  * Adding 32768 instead of 32767 just makes for round numbers.
 109  * Adding the decompressor_size is necessary as it musht live after all
 110  * of the data as well.  Last I measured the decompressor is about 14K.
 111  * 10K of actual data and 4K of bss.
 112  *
 113  */
 114
 115 /*
 116  * gzip declarations
 117  */
 118
 119 #define OF(args)  args
 120 #define STATIC static
 121
 122 #undef memset
 123 #undef memcpy
 124 #define memzero(s, n)     memset ((s), 0, (n))
 125
 126 typedef unsigned char  uch;
 127 typedef unsigned short ush;
 128 typedef unsigned long  ulg;
 129
 130 #define WSIZE 0x80000000        /* Window size must be at least 32k,
 131                                  * and a power of two
 132                                  * We don't actually have a window just
 133                                  * a huge output buffer so I report
 134                                  * a 2G windows size, as that should
 135                                  * always be larger than our output buffer.
 136                                  */
 137
 138 static uch *inbuf;      /* input buffer */
 139 static uch *window;     /* Sliding window buffer, (and final output buffer) */
 140
 141 static unsigned insize;  /* valid bytes in inbuf */
 142 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 143 static unsigned outcnt;  /* bytes in output buffer */
 144
 145 /* gzip flag byte */
 146 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 147 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 148 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 149 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 150 #define COMMENT      0x10 /* bit 4 set: file comment present */
 151 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 152 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 153
 154 #define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
 155
 156 /* Diagnostic functions */
 157 #ifdef DEBUG
 158 #  define Assert(cond,msg) {if(!(cond)) error(msg);}
 159 #  define Trace(x) fprintf x
 160 #  define Tracev(x) {if (verbose) fprintf x ;}
 161 #  define Tracevv(x) {if (verbose>1) fprintf x ;}
 162 #  define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
 163 #  define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
 164 #else
 165 #  define Assert(cond,msg)
 166 #  define Trace(x)
 167 #  define Tracev(x)
 168 #  define Tracevv(x)
 169 #  define Tracec(c,x)
 170 #  define Tracecv(c,x)
 171 #endif
 172
 173 static int  fill_inbuf(void);
 174 static void flush_window(void);
 175 static void error(char *m);
 176 static void gzip_mark(void **);
 177 static void gzip_release(void **);
 178
 179 /*
 180  * This is set up by the setup-routine at boot-time
 181  */
 182 static unsigned char *real_mode; /* Pointer to real-mode data */
 183
 184 #define RM_EXT_MEM_K   (*(unsigned short *)(real_mode + 0x2))
 185 #ifndef STANDARD_MEMORY_BIOS_CALL
 186 #define RM_ALT_MEM_K   (*(unsigned long *)(real_mode + 0x1e0))
 187 #endif
 188 #define RM_SCREEN_INFO (*(struct screen_info *)(real_mode+0))
 189
 190 extern unsigned char input_data[];
 191 extern int input_len;
 192
 193 static long bytes_out = 0;
 194
 195 static void *malloc(int size);
 196 static void free(void *where);
 197
 198 static void *memset(void *s, int c, unsigned n);
 199 static void *memcpy(void *dest, const void *src, unsigned n);
 200
 201 static void putstr(const char *);
 202
 203 #ifdef CONFIG_X86_64
 204 #define memptr long
 205 #else
 206 #define memptr unsigned
 207 #endif
 208
 209 static memptr free_mem_ptr;
 210 static memptr free_mem_end_ptr;
 211
 212 #ifdef CONFIG_X86_64
 213 #define HEAP_SIZE             0x7000
 214 #else
 215 #define HEAP_SIZE             0x4000
 216 #endif
 217
 218 static char *vidmem = (char *)0xb8000;
 219 static int vidport;
 220 static int lines, cols;
 221
 222 #ifdef CONFIG_X86_NUMAQ
 223 void *xquad_portio;
 224 #endif
 225
 226 #include "../../../../lib/inflate.c"
 227
 228 static void *malloc(int size)
 229 {
 230         void *p;
 231
 232         if (size <0) error("Malloc error");
 233         if (free_mem_ptr <= 0) error("Memory error");
 234
 235         free_mem_ptr = (free_mem_ptr + 3) & ~3; /* Align */
 236
 237         p = (void *)free_mem_ptr;
 238         free_mem_ptr += size;
 239
 240         if (free_mem_ptr >= free_mem_end_ptr)
 241                 error("Out of memory");
 242
 243         return p;
 244 }
 245
 246 static void free(void *where)
 247 {       /* Don't care */
 248 }
 249
 250 static void gzip_mark(void **ptr)
 251 {
 252         *ptr = (void *) free_mem_ptr;
 253 }
 254
 255 static void gzip_release(void **ptr)
 256 {
 257         free_mem_ptr = (memptr) *ptr;
 258 }
 259
 260 static void scroll(void)
 261 {
 262         int i;
 263
 264         memcpy ( vidmem, vidmem + cols * 2, ( lines - 1 ) * cols * 2 );
 265         for ( i = ( lines - 1 ) * cols * 2; i < lines * cols * 2; i += 2 )
 266                 vidmem[i] = ' ';
 267 }
 268
 269 static void putstr(const char *s)
 270 {
 271         int x,y,pos;
 272         char c;
 273
 274 #ifdef CONFIG_X86_32
 275         if (RM_SCREEN_INFO.orig_video_mode == 0 && lines == 0 && cols == 0)
 276                 return;
 277 #endif
 278
 279         x = RM_SCREEN_INFO.orig_x;
 280         y = RM_SCREEN_INFO.orig_y;
 281
 282         while ( ( c = *s++ ) != '\0' ) {
 283                 if ( c == '\n' ) {
 284                         x = 0;
 285                         if ( ++y >= lines ) {
 286                                 scroll();
 287                                 y--;
 288                         }
 289                 } else {
 290                         vidmem [(x + cols * y) * 2] = c;
 291                         if ( ++x >= cols ) {
 292                                 x = 0;
 293                                 if ( ++y >= lines ) {
 294                                         scroll();
 295                                         y--;
 296                                 }
 297                         }
 298                 }
 299         }
 300
 301         RM_SCREEN_INFO.orig_x = x;
 302         RM_SCREEN_INFO.orig_y = y;
 303
 304         pos = (x + cols * y) * 2;       /* Update cursor position */
 305         outb(14, vidport);
 306         outb(0xff & (pos >> 9), vidport+1);
 307         outb(15, vidport);
 308         outb(0xff & (pos >> 1), vidport+1);
 309 }
 310
 311 static void* memset(void* s, int c, unsigned n)
 312 {
 313         int i;
 314         char *ss = s;
 315
 316         for (i=0;i<n;i++) ss[i] = c;
 317         return s;
 318 }
 319
 320 static void* memcpy(void* dest, const void* src, unsigned n)
 321 {
 322         int i;
 323         const char *s = src;
 324         char *d = dest;
 325
 326         for (i=0;i<n;i++) d[i] = s[i];
 327         return dest;
 328 }
 329
 330 /* ===========================================================================
 331  * Fill the input buffer. This is called only when the buffer is empty
 332  * and at least one byte is really needed.
 333  */
 334 static int fill_inbuf(void)
 335 {
 336         error("ran out of input data");
 337         return 0;
 338 }
 339
 340 /* ===========================================================================
 341  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 342  * (Used for the decompressed data only.)
 343  */
 344 static void flush_window(void)
 345 {
 346         /* With my window equal to my output buffer
 347          * I only need to compute the crc here.
 348          */
 349         ulg c = crc;         /* temporary variable */
 350         unsigned n;
 351         uch *in, ch;
 352
 353         in = window;
 354         for (n = 0; n < outcnt; n++) {
 355                 ch = *in++;
 356                 c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 357         }
 358         crc = c;
 359         bytes_out += (ulg)outcnt;
 360         outcnt = 0;
 361 }
 362
 363 static void error(char *x)
 364 {
 365         putstr("\n\n");
 366         putstr(x);
 367         putstr("\n\n -- System halted");
 368
 369         while (1)
 370                 asm("hlt");
 371 }
 372
 373 static void parse_elf(void *output)
 374 {
 375 #ifdef CONFIG_X86_64
 376         Elf64_Ehdr ehdr;
 377         Elf64_Phdr *phdrs, *phdr;
 378 #else
 379         Elf32_Ehdr ehdr;
 380         Elf32_Phdr *phdrs, *phdr;
 381 #endif
 382         void *dest;
 383         int i;
 384
 385         memcpy(&ehdr, output, sizeof(ehdr));
 386         if(ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
 387            ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
 388            ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
 389            ehdr.e_ident[EI_MAG3] != ELFMAG3)
 390         {
 391                 error("Kernel is not a valid ELF file");
 392                 return;
 393         }
 394
 395         putstr("Parsing ELF... ");
 396
 397         phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
 398         if (!phdrs)
 399                 error("Failed to allocate space for phdrs");
 400
 401         memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
 402
 403         for (i=0; i<ehdr.e_phnum; i++) {
 404                 phdr = &phdrs[i];
 405
 406                 switch (phdr->p_type) {
 407                 case PT_LOAD:
 408 #ifdef CONFIG_RELOCATABLE
 409                         dest = output;
 410                         dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
 411 #else
 412                         dest = (void*)(phdr->p_paddr);
 413 #endif
 414                         memcpy(dest,
 415                                output + phdr->p_offset,
 416                                phdr->p_filesz);
 417                         break;
 418                 default: /* Ignore other PT_* */ break;
 419                 }
 420         }
 421 }
 422
 423 asmlinkage void decompress_kernel(void *rmode, memptr heap,
 424                                   uch *input_data, unsigned long input_len,
 425                                   uch *output)
 426 {
 427         real_mode = rmode;
 428
 429         if (RM_SCREEN_INFO.orig_video_mode == 7) {
 430                 vidmem = (char *) 0xb0000;
 431                 vidport = 0x3b4;
 432         } else {
 433                 vidmem = (char *) 0xb8000;
 434                 vidport = 0x3d4;
 435         }
 436
 437         lines = RM_SCREEN_INFO.orig_video_lines;
 438         cols = RM_SCREEN_INFO.orig_video_cols;
 439
 440         window = output;                /* Output buffer (Normally at 1M) */
 441         free_mem_ptr     = heap;        /* Heap */
 442         free_mem_end_ptr = heap + HEAP_SIZE;
 443         inbuf  = input_data;            /* Input buffer */
 444         insize = input_len;
 445         inptr  = 0;
 446
 447 #ifdef CONFIG_X86_64
 448         if ((ulg)output & (__KERNEL_ALIGN - 1))
 449                 error("Destination address not 2M aligned");
 450         if ((ulg)output >= 0xffffffffffUL)
 451                 error("Destination address too large");
 452 #else
 453         if ((u32)output & (CONFIG_PHYSICAL_ALIGN -1))
 454                 error("Destination address not CONFIG_PHYSICAL_ALIGN aligned");
 455         if (heap > ((-__PAGE_OFFSET-(512<<20)-1) & 0x7fffffff))
 456                 error("Destination address too large");
 457 #ifndef CONFIG_RELOCATABLE
 458         if ((u32)output != LOAD_PHYSICAL_ADDR)
 459                 error("Wrong destination address");
 460 #endif
 461 #endif
 462
 463         makecrc();
 464         putstr("\nDecompressing Linux... ");
 465         gunzip();
 466         parse_elf(output);
 467         putstr("done.\nBooting the kernel.\n");
 468         return;
 469 }