linux/arch/x86/boot/compressed/misc.c
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   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_64
  19#define _LINUX_STRING_H_ 1
  20#define __LINUX_BITMAP_H 1
  21#endif
  22
  23#include <linux/linkage.h>
  24#include <linux/screen_info.h>
  25#include <asm/io.h>
  26#include <asm/page.h>
  27#include <asm/boot.h>
  28
  29/* WARNING!!
  30 * This code is compiled with -fPIC and it is relocated dynamically
  31 * at run time, but no relocation processing is performed.
  32 * This means that it is not safe to place pointers in static structures.
  33 */
  34
  35/*
  36 * Getting to provable safe in place decompression is hard.
  37 * Worst case behaviours need to be analyzed.
  38 * Background information:
  39 *
  40 * The file layout is:
  41 *    magic[2]
  42 *    method[1]
  43 *    flags[1]
  44 *    timestamp[4]
  45 *    extraflags[1]
  46 *    os[1]
  47 *    compressed data blocks[N]
  48 *    crc[4] orig_len[4]
  49 *
  50 * resulting in 18 bytes of non compressed data overhead.
  51 *
  52 * Files divided into blocks
  53 * 1 bit (last block flag)
  54 * 2 bits (block type)
  55 *
  56 * 1 block occurs every 32K -1 bytes or when there 50% compression has been achieved.
  57 * The smallest block type encoding is always used.
  58 *
  59 * stored:
  60 *    32 bits length in bytes.
  61 *
  62 * fixed:
  63 *    magic fixed tree.
  64 *    symbols.
  65 *
  66 * dynamic:
  67 *    dynamic tree encoding.
  68 *    symbols.
  69 *
  70 *
  71 * The buffer for decompression in place is the length of the
  72 * uncompressed data, plus a small amount extra to keep the algorithm safe.
  73 * The compressed data is placed at the end of the buffer.  The output
  74 * pointer is placed at the start of the buffer and the input pointer
  75 * is placed where the compressed data starts.  Problems will occur
  76 * when the output pointer overruns the input pointer.
  77 *
  78 * The output pointer can only overrun the input pointer if the input
  79 * pointer is moving faster than the output pointer.  A condition only
  80 * triggered by data whose compressed form is larger than the uncompressed
  81 * form.
  82 *
  83 * The worst case at the block level is a growth of the compressed data
  84 * of 5 bytes per 32767 bytes.
  85 *
  86 * The worst case internal to a compressed block is very hard to figure.
  87 * The worst case can at least be boundined by having one bit that represents
  88 * 32764 bytes and then all of the rest of the bytes representing the very
  89 * very last byte.
  90 *
  91 * All of which is enough to compute an amount of extra data that is required
  92 * to be safe.  To avoid problems at the block level allocating 5 extra bytes
  93 * per 32767 bytes of data is sufficient.  To avoind problems internal to a block
  94 * adding an extra 32767 bytes (the worst case uncompressed block size) is
  95 * sufficient, to ensure that in the worst case the decompressed data for
  96 * block will stop the byte before the compressed data for a block begins.
  97 * To avoid problems with the compressed data's meta information an extra 18
  98 * bytes are needed.  Leading to the formula:
  99 *
 100 * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
 101 *
 102 * Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
 103 * Adding 32768 instead of 32767 just makes for round numbers.
 104 * Adding the decompressor_size is necessary as it musht live after all
 105 * of the data as well.  Last I measured the decompressor is about 14K.
 106 * 10K of actual data and 4K of bss.
 107 *
 108 */
 109
 110/*
 111 * gzip declarations
 112 */
 113
 114#define OF(args)  args
 115#define STATIC static
 116
 117#undef memset
 118#undef memcpy
 119#define memzero(s, n)     memset ((s), 0, (n))
 120
 121typedef unsigned char  uch;
 122typedef unsigned short ush;
 123typedef unsigned long  ulg;
 124
 125#define WSIZE 0x80000000        /* Window size must be at least 32k,
 126                                 * and a power of two
 127                                 * We don't actually have a window just
 128                                 * a huge output buffer so I report
 129                                 * a 2G windows size, as that should
 130                                 * always be larger than our output buffer.
 131                                 */
 132
 133static uch *inbuf;      /* input buffer */
 134static uch *window;     /* Sliding window buffer, (and final output buffer) */
 135
 136static unsigned insize;  /* valid bytes in inbuf */
 137static unsigned inptr;   /* index of next byte to be processed in inbuf */
 138static unsigned outcnt;  /* bytes in output buffer */
 139
 140/* gzip flag byte */
 141#define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 142#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 143#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 144#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 145#define COMMENT      0x10 /* bit 4 set: file comment present */
 146#define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 147#define RESERVED     0xC0 /* bit 6,7:   reserved */
 148
 149#define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
 150                
 151/* Diagnostic functions */
 152#ifdef DEBUG
 153#  define Assert(cond,msg) {if(!(cond)) error(msg);}
 154#  define Trace(x) fprintf x
 155#  define Tracev(x) {if (verbose) fprintf x ;}
 156#  define Tracevv(x) {if (verbose>1) fprintf x ;}
 157#  define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
 158#  define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
 159#else
 160#  define Assert(cond,msg)
 161#  define Trace(x)
 162#  define Tracev(x)
 163#  define Tracevv(x)
 164#  define Tracec(c,x)
 165#  define Tracecv(c,x)
 166#endif
 167
 168static int  fill_inbuf(void);
 169static void flush_window(void);
 170static void error(char *m);
 171static void gzip_mark(void **);
 172static void gzip_release(void **);
 173  
 174/*
 175 * This is set up by the setup-routine at boot-time
 176 */
 177static unsigned char *real_mode; /* Pointer to real-mode data */
 178
 179#define RM_EXT_MEM_K   (*(unsigned short *)(real_mode + 0x2))
 180#ifndef STANDARD_MEMORY_BIOS_CALL
 181#define RM_ALT_MEM_K   (*(unsigned long *)(real_mode + 0x1e0))
 182#endif
 183#define RM_SCREEN_INFO (*(struct screen_info *)(real_mode+0))
 184
 185extern unsigned char input_data[];
 186extern int input_len;
 187
 188static long bytes_out = 0;
 189
 190static void *malloc(int size);
 191static void free(void *where);
 192
 193static void *memset(void *s, int c, unsigned n);
 194static void *memcpy(void *dest, const void *src, unsigned n);
 195
 196static void putstr(const char *);
 197
 198#ifdef CONFIG_X86_64
 199#define memptr long
 200#else
 201#define memptr unsigned
 202#endif
 203
 204static memptr free_mem_ptr;
 205static memptr free_mem_end_ptr;
 206
 207#ifdef CONFIG_X86_64
 208#define HEAP_SIZE             0x7000
 209#else
 210#define HEAP_SIZE             0x4000
 211#endif
 212
 213static char *vidmem = (char *)0xb8000;
 214static int vidport;
 215static int lines, cols;
 216
 217#ifdef CONFIG_X86_NUMAQ
 218void *xquad_portio;
 219#endif
 220
 221#include "../../../../lib/inflate.c"
 222
 223static void *malloc(int size)
 224{
 225        void *p;
 226
 227        if (size <0) error("Malloc error");
 228        if (free_mem_ptr <= 0) error("Memory error");
 229
 230        free_mem_ptr = (free_mem_ptr + 3) & ~3; /* Align */
 231
 232        p = (void *)free_mem_ptr;
 233        free_mem_ptr += size;
 234
 235        if (free_mem_ptr >= free_mem_end_ptr)
 236                error("Out of memory");
 237
 238        return p;
 239}
 240
 241static void free(void *where)
 242{       /* Don't care */
 243}
 244
 245static void gzip_mark(void **ptr)
 246{
 247        *ptr = (void *) free_mem_ptr;
 248}
 249
 250static void gzip_release(void **ptr)
 251{
 252        free_mem_ptr = (memptr) *ptr;
 253}
 254 
 255static void scroll(void)
 256{
 257        int i;
 258
 259        memcpy ( vidmem, vidmem + cols * 2, ( lines - 1 ) * cols * 2 );
 260        for ( i = ( lines - 1 ) * cols * 2; i < lines * cols * 2; i += 2 )
 261                vidmem[i] = ' ';
 262}
 263
 264static void putstr(const char *s)
 265{
 266        int x,y,pos;
 267        char c;
 268
 269#ifdef CONFIG_X86_32
 270        if (RM_SCREEN_INFO.orig_video_mode == 0 && lines == 0 && cols == 0)
 271                return;
 272#endif
 273
 274        x = RM_SCREEN_INFO.orig_x;
 275        y = RM_SCREEN_INFO.orig_y;
 276
 277        while ( ( c = *s++ ) != '\0' ) {
 278                if ( c == '\n' ) {
 279                        x = 0;
 280                        if ( ++y >= lines ) {
 281                                scroll();
 282                                y--;
 283                        }
 284                } else {
 285                        vidmem [(x + cols * y) * 2] = c;
 286                        if ( ++x >= cols ) {
 287                                x = 0;
 288                                if ( ++y >= lines ) {
 289                                        scroll();
 290                                        y--;
 291                                }
 292                        }
 293                }
 294        }
 295
 296        RM_SCREEN_INFO.orig_x = x;
 297        RM_SCREEN_INFO.orig_y = y;
 298
 299        pos = (x + cols * y) * 2;       /* Update cursor position */
 300        outb(14, vidport);
 301        outb(0xff & (pos >> 9), vidport+1);
 302        outb(15, vidport);
 303        outb(0xff & (pos >> 1), vidport+1);
 304}
 305
 306static void* memset(void* s, int c, unsigned n)
 307{
 308        int i;
 309        char *ss = s;
 310
 311        for (i=0;i<n;i++) ss[i] = c;
 312        return s;
 313}
 314
 315static void* memcpy(void* dest, const void* src, unsigned n)
 316{
 317        int i;
 318        const char *s = src;
 319        char *d = dest;
 320
 321        for (i=0;i<n;i++) d[i] = s[i];
 322        return dest;
 323}
 324
 325/* ===========================================================================
 326 * Fill the input buffer. This is called only when the buffer is empty
 327 * and at least one byte is really needed.
 328 */
 329static int fill_inbuf(void)
 330{
 331        error("ran out of input data");
 332        return 0;
 333}
 334
 335/* ===========================================================================
 336 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 337 * (Used for the decompressed data only.)
 338 */
 339static void flush_window(void)
 340{
 341        /* With my window equal to my output buffer
 342         * I only need to compute the crc here.
 343         */
 344        ulg c = crc;         /* temporary variable */
 345        unsigned n;
 346        uch *in, ch;
 347
 348        in = window;
 349        for (n = 0; n < outcnt; n++) {
 350                ch = *in++;
 351                c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
 352        }
 353        crc = c;
 354        bytes_out += (ulg)outcnt;
 355        outcnt = 0;
 356}
 357
 358static void error(char *x)
 359{
 360        putstr("\n\n");
 361        putstr(x);
 362        putstr("\n\n -- System halted");
 363
 364        while (1)
 365                asm("hlt");
 366}
 367
 368asmlinkage void decompress_kernel(void *rmode, memptr heap,
 369                                  uch *input_data, unsigned long input_len,
 370                                  uch *output)
 371{
 372        real_mode = rmode;
 373
 374        if (RM_SCREEN_INFO.orig_video_mode == 7) {
 375                vidmem = (char *) 0xb0000;
 376                vidport = 0x3b4;
 377        } else {
 378                vidmem = (char *) 0xb8000;
 379                vidport = 0x3d4;
 380        }
 381
 382        lines = RM_SCREEN_INFO.orig_video_lines;
 383        cols = RM_SCREEN_INFO.orig_video_cols;
 384
 385        window = output;                /* Output buffer (Normally at 1M) */
 386        free_mem_ptr     = heap;        /* Heap */
 387        free_mem_end_ptr = heap + HEAP_SIZE;
 388        inbuf  = input_data;            /* Input buffer */
 389        insize = input_len;
 390        inptr  = 0;
 391
 392#ifdef CONFIG_X86_64
 393        if ((ulg)output & (__KERNEL_ALIGN - 1))
 394                error("Destination address not 2M aligned");
 395        if ((ulg)output >= 0xffffffffffUL)
 396                error("Destination address too large");
 397#else
 398        if ((u32)output & (CONFIG_PHYSICAL_ALIGN -1))
 399                error("Destination address not CONFIG_PHYSICAL_ALIGN aligned");
 400        if (heap > ((-__PAGE_OFFSET-(512<<20)-1) & 0x7fffffff))
 401                error("Destination address too large");
 402#ifndef CONFIG_RELOCATABLE
 403        if ((u32)output != LOAD_PHYSICAL_ADDR)
 404                error("Wrong destination address");
 405#endif
 406#endif
 407
 408        makecrc();
 409        putstr("\nDecompressing Linux... ");
 410        gunzip();
 411        putstr("done.\nBooting the kernel.\n");
 412        return;
 413}
 414
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