release/src-rt-6.x/linux/linux-2.6/arch/i386/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 #undef CONFIG_PARAVIRT
  13 #include <linux/linkage.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/screen_info.h>
  16 #include <asm/io.h>
  17 #include <asm/page.h>
  18 #include <asm/boot.h>
  19
  20 /* WARNING!!
  21  * This code is compiled with -fPIC and it is relocated dynamically
  22  * at run time, but no relocation processing is performed.
  23  * This means that it is not safe to place pointers in static structures.
  24  */
  25
  26 /*
  27  * Getting to provable safe in place decompression is hard.
  28  * Worst case behaviours need to be analized.
  29  * Background information:
  30  *
  31  * The file layout is:
  32  *    magic[2]
  33  *    method[1]
  34  *    flags[1]
  35  *    timestamp[4]
  36  *    extraflags[1]
  37  *    os[1]
  38  *    compressed data blocks[N]
  39  *    crc[4] orig_len[4]
  40  *
  41  * resulting in 18 bytes of non compressed data overhead.
  42  *
  43  * Files divided into blocks
  44  * 1 bit (last block flag)
  45  * 2 bits (block type)
  46  *
  47  * 1 block occurs every 32K -1 bytes or when there 50% compression has been achieved.
  48  * The smallest block type encoding is always used.
  49  *
  50  * stored:
  51  *    32 bits length in bytes.
  52  *
  53  * fixed:
  54  *    magic fixed tree.
  55  *    symbols.
  56  *
  57  * dynamic:
  58  *    dynamic tree encoding.
  59  *    symbols.
  60  *
  61  *
  62  * The buffer for decompression in place is the length of the
  63  * uncompressed data, plus a small amount extra to keep the algorithm safe.
  64  * The compressed data is placed at the end of the buffer.  The output
  65  * pointer is placed at the start of the buffer and the input pointer
  66  * is placed where the compressed data starts.  Problems will occur
  67  * when the output pointer overruns the input pointer.
  68  *
  69  * The output pointer can only overrun the input pointer if the input
  70  * pointer is moving faster than the output pointer.  A condition only
  71  * triggered by data whose compressed form is larger than the uncompressed
  72  * form.
  73  *
  74  * The worst case at the block level is a growth of the compressed data
  75  * of 5 bytes per 32767 bytes.
  76  *
  77  * The worst case internal to a compressed block is very hard to figure.
  78  * The worst case can at least be boundined by having one bit that represents
  79  * 32764 bytes and then all of the rest of the bytes representing the very
  80  * very last byte.
  81  *
  82  * All of which is enough to compute an amount of extra data that is required
  83  * to be safe.  To avoid problems at the block level allocating 5 extra bytes
  84  * per 32767 bytes of data is sufficient.  To avoind problems internal to a block
  85  * adding an extra 32767 bytes (the worst case uncompressed block size) is
  86  * sufficient, to ensure that in the worst case the decompressed data for
  87  * block will stop the byte before the compressed data for a block begins.
  88  * To avoid problems with the compressed data's meta information an extra 18
  89  * bytes are needed.  Leading to the formula:
  90  *
  91  * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
  92  *
  93  * Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
  94  * Adding 32768 instead of 32767 just makes for round numbers.
  95  * Adding the decompressor_size is necessary as it musht live after all
  96  * of the data as well.  Last I measured the decompressor is about 14K.
  97  * 10K of actuall data and 4K of bss.
  98  *
  99  */
 100
 101 /*
 102  * gzip declarations
 103  */
 104
 105 #define OF(args)  args
 106 #define STATIC static
 107
 108 #undef memset
 109 #undef memcpy
 110 #define memzero(s, n)     memset ((s), 0, (n))
 111
 112 typedef unsigned char  uch;
 113 typedef unsigned short ush;
 114 typedef unsigned long  ulg;
 115
 116 #define WSIZE 0x80000000        /* Window size must be at least 32k,
 117                                  * and a power of two
 118                                  * We don't actually have a window just
 119                                  * a huge output buffer so I report
 120                                  * a 2G windows size, as that should
 121                                  * always be larger than our output buffer.
 122                                  */
 123
 124 static uch *inbuf;      /* input buffer */
 125 static uch *window;     /* Sliding window buffer, (and final output buffer) */
 126
 127 static unsigned insize;  /* valid bytes in inbuf */
 128 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 129 static unsigned outcnt;  /* bytes in output buffer */
 130
 131 /* gzip flag byte */
 132 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 133 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 134 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 135 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 136 #define COMMENT      0x10 /* bit 4 set: file comment present */
 137 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 138 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 139
 140 #define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
 141
 142 /* Diagnostic functions */
 143 #ifdef DEBUG
 144 #  define Assert(cond,msg) {if(!(cond)) error(msg);}
 145 #  define Trace(x) fprintf x
 146 #  define Tracev(x) {if (verbose) fprintf x ;}
 147 #  define Tracevv(x) {if (verbose>1) fprintf x ;}
 148 #  define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
 149 #  define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
 150 #else
 151 #  define Assert(cond,msg)
 152 #  define Trace(x)
 153 #  define Tracev(x)
 154 #  define Tracevv(x)
 155 #  define Tracec(c,x)
 156 #  define Tracecv(c,x)
 157 #endif
 158
 159 static int  fill_inbuf(void);
 160 static void flush_window(void);
 161 static void error(char *m);
 162 static void gzip_mark(void **);
 163 static void gzip_release(void **);
 164
 165 /*
 166  * This is set up by the setup-routine at boot-time
 167  */
 168 static unsigned char *real_mode; /* Pointer to real-mode data */
 169
 170 #define RM_EXT_MEM_K   (*(unsigned short *)(real_mode + 0x2))
 171 #ifndef STANDARD_MEMORY_BIOS_CALL
 172 #define RM_ALT_MEM_K   (*(unsigned long *)(real_mode + 0x1e0))
 173 #endif
 174 #define RM_SCREEN_INFO (*(struct screen_info *)(real_mode+0))
 175
 176 extern unsigned char input_data[];
 177 extern int input_len;
 178
 179 static long bytes_out = 0;
 180
 181 static void *malloc(int size);
 182 static void free(void *where);
 183
 184 static void *memset(void *s, int c, unsigned n);
 185 static void *memcpy(void *dest, const void *src, unsigned n);
 186
 187 static void putstr(const char *);
 188
 189 static unsigned long free_mem_ptr;
 190 static unsigned long free_mem_end_ptr;
 191
 192 #define HEAP_SIZE             0x4000
 193
 194 static char *vidmem = (char *)0xb8000;
 195 static int vidport;
 196 static int lines, cols;
 197
 198 #ifdef CONFIG_X86_NUMAQ
 199 void *xquad_portio;
 200 #endif
 201
 202 #include "../../../../lib/inflate.c"
 203
 204 static void *malloc(int size)
 205 {
 206         void *p;
 207
 208         if (size <0) error("Malloc error");
 209         if (free_mem_ptr <= 0) error("Memory error");
 210
 211         free_mem_ptr = (free_mem_ptr + 3) & ~3; /* Align */
 212
 213         p = (void *)free_mem_ptr;
 214         free_mem_ptr += size;
 215
 216         if (free_mem_ptr >= free_mem_end_ptr)
 217                 error("Out of memory");
 218
 219         return p;
 220 }
 221
 222 static void free(void *where)
 223 {       /* Don't care */
 224 }
 225
 226 static void gzip_mark(void **ptr)
 227 {
 228         *ptr = (void *) free_mem_ptr;
 229 }
 230
 231 static void gzip_release(void **ptr)
 232 {
 233         free_mem_ptr = (unsigned long) *ptr;
 234 }
 235
 236 static void scroll(void)
 237 {
 238         int i;
 239
 240         memcpy ( vidmem, vidmem + cols * 2, ( lines - 1 ) * cols * 2 );
 241         for ( i = ( lines - 1 ) * cols * 2; i < lines * cols * 2; i += 2 )
 242                 vidmem[i] = ' ';
 243 }
 244
 245 static void putstr(const char *s)
 246 {
 247         int x,y,pos;
 248         char c;
 249
 250         x = RM_SCREEN_INFO.orig_x;
 251         y = RM_SCREEN_INFO.orig_y;
 252
 253         while ( ( c = *s++ ) != '\0' ) {
 254                 if ( c == '\n' ) {
 255                         x = 0;
 256                         if ( ++y >= lines ) {
 257                                 scroll();
 258                                 y--;
 259                         }
 260                 } else {
 261                         vidmem [ ( x + cols * y ) * 2 ] = c;
 262                         if ( ++x >= cols ) {
 263                                 x = 0;
 264                                 if ( ++y >= lines ) {
 265                                         scroll();
 266                                         y--;
 267                                 }
 268                         }
 269                 }
 270         }
 271
 272         RM_SCREEN_INFO.orig_x = x;
 273         RM_SCREEN_INFO.orig_y = y;
 274
 275         pos = (x + cols * y) * 2;       /* Update cursor position */
 276         outb_p(14, vidport);
 277         outb_p(0xff & (pos >> 9), vidport+1);
 278         outb_p(15, vidport);
 279         outb_p(0xff & (pos >> 1), vidport+1);
 280 }
 281
 282 static void* memset(void* s, int c, unsigned n)
 283 {
 284         int i;
 285         char *ss = (char*)s;
 286
 287         for (i=0;i<n;i++) ss[i] = c;
 288         return s;
 289 }
 290
 291 static void* memcpy(void* dest, const void* src, unsigned n)
 292 {
 293         int i;
 294         char *d = (char *)dest, *s = (char *)src;
 295
 296         for (i=0;i<n;i++) d[i] = s[i];
 297         return dest;
 298 }
 299
 300 /* ===========================================================================
 301  * Fill the input buffer. This is called only when the buffer is empty
 302  * and at least one byte is really needed.
 303  */
 304 static int fill_inbuf(void)
 305 {
 306         error("ran out of input data");
 307         return 0;
 308 }
 309
 310 /* ===========================================================================
 311  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 312  * (Used for the decompressed data only.)
 313  */
 314 static void flush_window(void)
 315 {
 316         /* With my window equal to my output buffer
 317          * I only need to compute the crc here.
 318          */
 319         ulg c = crc;         /* temporary variable */
 320         unsigned n;
 321         uch *in, ch;
 322
 323         in = window;
 324         for (n = 0; n < outcnt; n++) {
 325                 ch = *in++;
 326                 c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 327         }
 328         crc = c;
 329         bytes_out += (ulg)outcnt;
 330         outcnt = 0;
 331 }
 332
 333 static void error(char *x)
 334 {
 335         putstr("\n\n");
 336         putstr(x);
 337         putstr("\n\n -- System halted");
 338
 339         while(1);       /* Halt */
 340 }
 341
 342 asmlinkage void decompress_kernel(void *rmode, unsigned long end,
 343                         uch *input_data, unsigned long input_len, uch *output)
 344 {
 345         real_mode = rmode;
 346
 347         if (RM_SCREEN_INFO.orig_video_mode == 7) {
 348                 vidmem = (char *) 0xb0000;
 349                 vidport = 0x3b4;
 350         } else {
 351                 vidmem = (char *) 0xb8000;
 352                 vidport = 0x3d4;
 353         }
 354
 355         lines = RM_SCREEN_INFO.orig_video_lines;
 356         cols = RM_SCREEN_INFO.orig_video_cols;
 357
 358         window = output;        /* Output buffer (Normally at 1M) */
 359         free_mem_ptr     = end; /* Heap  */
 360         free_mem_end_ptr = end + HEAP_SIZE;
 361         inbuf  = input_data;    /* Input buffer */
 362         insize = input_len;
 363         inptr  = 0;
 364
 365         if ((u32)output & (CONFIG_PHYSICAL_ALIGN -1))
 366                 error("Destination address not CONFIG_PHYSICAL_ALIGN aligned");
 367         if (end > ((-__PAGE_OFFSET-(512 <<20)-1) & 0x7fffffff))
 368                 error("Destination address too large");
 369 #ifndef CONFIG_RELOCATABLE
 370         if ((u32)output != LOAD_PHYSICAL_ADDR)
 371                 error("Wrong destination address");
 372 #endif
 373
 374         makecrc();
 375         putstr("Uncompressing Linux... ");
 376         gunzip();
 377         putstr("Ok, booting the kernel.\n");
 378         return;
 379 }