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_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
 121 typedef unsigned char  uch;
 122 typedef unsigned short ush;
 123 typedef 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
 133 static uch *inbuf;      /* input buffer */
 134 static uch *window;     /* Sliding window buffer, (and final output buffer) */
 135
 136 static unsigned insize;  /* valid bytes in inbuf */
 137 static unsigned inptr;   /* index of next byte to be processed in inbuf */
 138 static 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
 168 static int  fill_inbuf(void);
 169 static void flush_window(void);
 170 static void error(char *m);
 171 static void gzip_mark(void **);
 172 static void gzip_release(void **);
 173
 174 /*
 175  * This is set up by the setup-routine at boot-time
 176  */
 177 static 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
 185 extern unsigned char input_data[];
 186 extern int input_len;
 187
 188 static long bytes_out = 0;
 189
 190 static void *malloc(int size);
 191 static void free(void *where);
 192
 193 static void *memset(void *s, int c, unsigned n);
 194 static void *memcpy(void *dest, const void *src, unsigned n);
 195
 196 static void putstr(const char *);
 197
 198 #ifdef CONFIG_X86_64
 199 #define memptr long
 200 #else
 201 #define memptr unsigned
 202 #endif
 203
 204 static memptr free_mem_ptr;
 205 static 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
 213 static char *vidmem = (char *)0xb8000;
 214 static int vidport;
 215 static int lines, cols;
 216
 217 #ifdef CONFIG_X86_NUMAQ
 218 void *xquad_portio;
 219 #endif
 220
 221 #include "../../../../lib/inflate.c"
 222
 223 static 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
 241 static void free(void *where)
 242 {       /* Don't care */
 243 }
 244
 245 static void gzip_mark(void **ptr)
 246 {
 247         *ptr = (void *) free_mem_ptr;
 248 }
 249
 250 static void gzip_release(void **ptr)
 251 {
 252         free_mem_ptr = (memptr) *ptr;
 253 }
 254
 255 static 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
 264 static 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
 306 static 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
 315 static 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  */
 329 static 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  */
 339 static 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
 358 static 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
 368 asmlinkage 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 }