arch/x86_64/boot/compressed/misc_64.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 #define _LINUX_STRING_H_ 1
  13 #define __LINUX_BITMAP_H 1
  14
  15 #include <linux/linkage.h>
  16 #include <linux/screen_info.h>
  17 #include <asm/io.h>
  18 #include <asm/page.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 long free_mem_ptr;
 190 static long free_mem_end_ptr;
 191
 192 #define HEAP_SIZE             0x7000
 193
 194 static char *vidmem = (char *)0xb8000;
 195 static int vidport;
 196 static int lines, cols;
 197
 198 #include "../../../../lib/inflate.c"
 199
 200 static void *malloc(int size)
 201 {
 202         void *p;
 203
 204         if (size <0) error("Malloc error");
 205         if (free_mem_ptr <= 0) error("Memory error");
 206
 207         free_mem_ptr = (free_mem_ptr + 3) & ~3; /* Align */
 208
 209         p = (void *)free_mem_ptr;
 210         free_mem_ptr += size;
 211
 212         if (free_mem_ptr >= free_mem_end_ptr)
 213                 error("Out of memory");
 214
 215         return p;
 216 }
 217
 218 static void free(void *where)
 219 {       /* Don't care */
 220 }
 221
 222 static void gzip_mark(void **ptr)
 223 {
 224         *ptr = (void *) free_mem_ptr;
 225 }
 226
 227 static void gzip_release(void **ptr)
 228 {
 229         free_mem_ptr = (long) *ptr;
 230 }
 231
 232 static void scroll(void)
 233 {
 234         int i;
 235
 236         memcpy ( vidmem, vidmem + cols * 2, ( lines - 1 ) * cols * 2 );
 237         for ( i = ( lines - 1 ) * cols * 2; i < lines * cols * 2; i += 2 )
 238                 vidmem[i] = ' ';
 239 }
 240
 241 static void putstr(const char *s)
 242 {
 243         int x,y,pos;
 244         char c;
 245
 246         x = RM_SCREEN_INFO.orig_x;
 247         y = RM_SCREEN_INFO.orig_y;
 248
 249         while ( ( c = *s++ ) != '\0' ) {
 250                 if ( c == '\n' ) {
 251                         x = 0;
 252                         if ( ++y >= lines ) {
 253                                 scroll();
 254                                 y--;
 255                         }
 256                 } else {
 257                         vidmem [ ( x + cols * y ) * 2 ] = c;
 258                         if ( ++x >= cols ) {
 259                                 x = 0;
 260                                 if ( ++y >= lines ) {
 261                                         scroll();
 262                                         y--;
 263                                 }
 264                         }
 265                 }
 266         }
 267
 268         RM_SCREEN_INFO.orig_x = x;
 269         RM_SCREEN_INFO.orig_y = y;
 270
 271         pos = (x + cols * y) * 2;       /* Update cursor position */
 272         outb_p(14, vidport);
 273         outb_p(0xff & (pos >> 9), vidport+1);
 274         outb_p(15, vidport);
 275         outb_p(0xff & (pos >> 1), vidport+1);
 276 }
 277
 278 static void* memset(void* s, int c, unsigned n)
 279 {
 280         int i;
 281         char *ss = (char*)s;
 282
 283         for (i=0;i<n;i++) ss[i] = c;
 284         return s;
 285 }
 286
 287 static void* memcpy(void* dest, const void* src, unsigned n)
 288 {
 289         int i;
 290         char *d = (char *)dest, *s = (char *)src;
 291
 292         for (i=0;i<n;i++) d[i] = s[i];
 293         return dest;
 294 }
 295
 296 /* ===========================================================================
 297  * Fill the input buffer. This is called only when the buffer is empty
 298  * and at least one byte is really needed.
 299  */
 300 static int fill_inbuf(void)
 301 {
 302         error("ran out of input data");
 303         return 0;
 304 }
 305
 306 /* ===========================================================================
 307  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 308  * (Used for the decompressed data only.)
 309  */
 310 static void flush_window(void)
 311 {
 312         /* With my window equal to my output buffer
 313          * I only need to compute the crc here.
 314          */
 315         ulg c = crc;         /* temporary variable */
 316         unsigned n;
 317         uch *in, ch;
 318
 319         in = window;
 320         for (n = 0; n < outcnt; n++) {
 321                 ch = *in++;
 322                 c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 323         }
 324         crc = c;
 325         bytes_out += (ulg)outcnt;
 326         outcnt = 0;
 327 }
 328
 329 static void error(char *x)
 330 {
 331         putstr("\n\n");
 332         putstr(x);
 333         putstr("\n\n -- System halted");
 334
 335         while(1);       /* Halt */
 336 }
 337
 338 asmlinkage void decompress_kernel(void *rmode, unsigned long heap,
 339         uch *input_data, unsigned long input_len, uch *output)
 340 {
 341         real_mode = rmode;
 342
 343         if (RM_SCREEN_INFO.orig_video_mode == 7) {
 344                 vidmem = (char *) 0xb0000;
 345                 vidport = 0x3b4;
 346         } else {
 347                 vidmem = (char *) 0xb8000;
 348                 vidport = 0x3d4;
 349         }
 350
 351         lines = RM_SCREEN_INFO.orig_video_lines;
 352         cols = RM_SCREEN_INFO.orig_video_cols;
 353
 354         window = output;                /* Output buffer (Normally at 1M) */
 355         free_mem_ptr     = heap;        /* Heap  */
 356         free_mem_end_ptr = heap + HEAP_SIZE;
 357         inbuf  = input_data;            /* Input buffer */
 358         insize = input_len;
 359         inptr  = 0;
 360
 361         if ((ulg)output & (__KERNEL_ALIGN - 1))
 362                 error("Destination address not 2M aligned");
 363         if ((ulg)output >= 0xffffffffffUL)
 364                 error("Destination address too large");
 365
 366         makecrc();
 367         putstr(".\nDecompressing Linux...");
 368         gunzip();
 369         putstr("done.\nBooting the kernel.\n");
 370         return;
 371 }