442 lines
11 KiB
C
442 lines
11 KiB
C
/*
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* misc.c
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*
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* This is a collection of several routines from gzip-1.0.3
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* adapted for Linux.
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*
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* malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
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* puts by Nick Holloway 1993, better puts by Martin Mares 1995
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* High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
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*/
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/*
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* we have to be careful, because no indirections are allowed here, and
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* paravirt_ops is a kind of one. As it will only run in baremetal anyway,
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* we just keep it from happening
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*/
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#undef CONFIG_PARAVIRT
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#ifdef CONFIG_X86_32
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#define _ASM_X86_DESC_H 1
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#endif
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#ifdef CONFIG_X86_64
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#define _LINUX_STRING_H_ 1
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#define __LINUX_BITMAP_H 1
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#endif
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#include <linux/linkage.h>
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#include <linux/screen_info.h>
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#include <linux/elf.h>
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#include <linux/io.h>
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#include <asm/page.h>
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#include <asm/boot.h>
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#include <asm/bootparam.h>
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/* WARNING!!
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* This code is compiled with -fPIC and it is relocated dynamically
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* at run time, but no relocation processing is performed.
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* This means that it is not safe to place pointers in static structures.
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*/
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/*
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* Getting to provable safe in place decompression is hard.
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* Worst case behaviours need to be analyzed.
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* Background information:
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*
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* The file layout is:
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* magic[2]
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* method[1]
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* flags[1]
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* timestamp[4]
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* extraflags[1]
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* os[1]
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* compressed data blocks[N]
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* crc[4] orig_len[4]
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*
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* resulting in 18 bytes of non compressed data overhead.
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*
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* Files divided into blocks
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* 1 bit (last block flag)
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* 2 bits (block type)
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*
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* 1 block occurs every 32K -1 bytes or when there 50% compression
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* has been achieved. The smallest block type encoding is always used.
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*
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* stored:
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* 32 bits length in bytes.
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*
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* fixed:
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* magic fixed tree.
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* symbols.
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*
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* dynamic:
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* dynamic tree encoding.
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* symbols.
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*
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*
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* The buffer for decompression in place is the length of the
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* uncompressed data, plus a small amount extra to keep the algorithm safe.
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* The compressed data is placed at the end of the buffer. The output
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* pointer is placed at the start of the buffer and the input pointer
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* is placed where the compressed data starts. Problems will occur
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* when the output pointer overruns the input pointer.
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*
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* The output pointer can only overrun the input pointer if the input
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* pointer is moving faster than the output pointer. A condition only
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* triggered by data whose compressed form is larger than the uncompressed
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* form.
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*
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* The worst case at the block level is a growth of the compressed data
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* of 5 bytes per 32767 bytes.
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*
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* The worst case internal to a compressed block is very hard to figure.
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* The worst case can at least be boundined by having one bit that represents
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* 32764 bytes and then all of the rest of the bytes representing the very
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* very last byte.
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*
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* All of which is enough to compute an amount of extra data that is required
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* to be safe. To avoid problems at the block level allocating 5 extra bytes
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* per 32767 bytes of data is sufficient. To avoind problems internal to a
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* block adding an extra 32767 bytes (the worst case uncompressed block size)
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* is sufficient, to ensure that in the worst case the decompressed data for
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* block will stop the byte before the compressed data for a block begins.
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* To avoid problems with the compressed data's meta information an extra 18
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* bytes are needed. Leading to the formula:
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*
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* extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
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*
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* Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
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* Adding 32768 instead of 32767 just makes for round numbers.
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* Adding the decompressor_size is necessary as it musht live after all
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* of the data as well. Last I measured the decompressor is about 14K.
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* 10K of actual data and 4K of bss.
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*
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*/
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/*
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* gzip declarations
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*/
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#define OF(args) args
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#define STATIC static
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#undef memset
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#undef memcpy
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#define memzero(s, n) memset((s), 0, (n))
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typedef unsigned char uch;
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typedef unsigned short ush;
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typedef unsigned long ulg;
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/*
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* Window size must be at least 32k, and a power of two.
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* We don't actually have a window just a huge output buffer,
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* so we report a 2G window size, as that should always be
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* larger than our output buffer:
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*/
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#define WSIZE 0x80000000
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/* Input buffer: */
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static unsigned char *inbuf;
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/* Sliding window buffer (and final output buffer): */
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static unsigned char *window;
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/* Valid bytes in inbuf: */
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static unsigned insize;
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/* Index of next byte to be processed in inbuf: */
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static unsigned inptr;
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/* Bytes in output buffer: */
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static unsigned outcnt;
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/* gzip flag byte */
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#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
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#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gz file */
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#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
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#define ORIG_NAM 0x08 /* bit 3 set: original file name present */
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#define COMMENT 0x10 /* bit 4 set: file comment present */
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#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
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#define RESERVED 0xC0 /* bit 6, 7: reserved */
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#define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf())
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/* Diagnostic functions */
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#ifdef DEBUG
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# define Assert(cond, msg) do { if (!(cond)) error(msg); } while (0)
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# define Trace(x) do { fprintf x; } while (0)
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# define Tracev(x) do { if (verbose) fprintf x ; } while (0)
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# define Tracevv(x) do { if (verbose > 1) fprintf x ; } while (0)
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# define Tracec(c, x) do { if (verbose && (c)) fprintf x ; } while (0)
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# define Tracecv(c, x) do { if (verbose > 1 && (c)) fprintf x ; } while (0)
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#else
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# define Assert(cond, msg)
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# define Trace(x)
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# define Tracev(x)
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# define Tracevv(x)
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# define Tracec(c, x)
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# define Tracecv(c, x)
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#endif
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static int fill_inbuf(void);
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static void flush_window(void);
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static void error(char *m);
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/*
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* This is set up by the setup-routine at boot-time
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*/
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static struct boot_params *real_mode; /* Pointer to real-mode data */
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static int quiet;
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extern unsigned char input_data[];
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extern int input_len;
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static long bytes_out;
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static void *memset(void *s, int c, unsigned n);
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static void *memcpy(void *dest, const void *src, unsigned n);
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static void __putstr(int, const char *);
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#define putstr(__x) __putstr(0, __x)
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#ifdef CONFIG_X86_64
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#define memptr long
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#else
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#define memptr unsigned
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#endif
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static memptr free_mem_ptr;
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static memptr free_mem_end_ptr;
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static char *vidmem;
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static int vidport;
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static int lines, cols;
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#include "../../../../lib/inflate.c"
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static void scroll(void)
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{
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int i;
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memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
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for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
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vidmem[i] = ' ';
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}
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static void __putstr(int error, const char *s)
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{
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int x, y, pos;
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char c;
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#ifndef CONFIG_X86_VERBOSE_BOOTUP
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if (!error)
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return;
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#endif
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#ifdef CONFIG_X86_32
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if (real_mode->screen_info.orig_video_mode == 0 &&
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lines == 0 && cols == 0)
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return;
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#endif
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x = real_mode->screen_info.orig_x;
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y = real_mode->screen_info.orig_y;
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while ((c = *s++) != '\0') {
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if (c == '\n') {
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x = 0;
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if (++y >= lines) {
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scroll();
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y--;
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}
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} else {
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vidmem[(x + cols * y) * 2] = c;
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if (++x >= cols) {
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x = 0;
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if (++y >= lines) {
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scroll();
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y--;
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}
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}
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}
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}
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real_mode->screen_info.orig_x = x;
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real_mode->screen_info.orig_y = y;
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pos = (x + cols * y) * 2; /* Update cursor position */
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outb(14, vidport);
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outb(0xff & (pos >> 9), vidport+1);
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outb(15, vidport);
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outb(0xff & (pos >> 1), vidport+1);
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}
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static void *memset(void *s, int c, unsigned n)
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{
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int i;
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char *ss = s;
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for (i = 0; i < n; i++)
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ss[i] = c;
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return s;
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}
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static void *memcpy(void *dest, const void *src, unsigned n)
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{
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int i;
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const char *s = src;
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char *d = dest;
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for (i = 0; i < n; i++)
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d[i] = s[i];
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return dest;
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}
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/* ===========================================================================
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* Fill the input buffer. This is called only when the buffer is empty
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* and at least one byte is really needed.
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*/
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static int fill_inbuf(void)
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{
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error("ran out of input data");
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return 0;
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}
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/* ===========================================================================
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* Write the output window window[0..outcnt-1] and update crc and bytes_out.
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* (Used for the decompressed data only.)
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*/
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static void flush_window(void)
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{
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/* With my window equal to my output buffer
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* I only need to compute the crc here.
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*/
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unsigned long c = crc; /* temporary variable */
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unsigned n;
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unsigned char *in, ch;
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in = window;
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for (n = 0; n < outcnt; n++) {
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ch = *in++;
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c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
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}
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crc = c;
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bytes_out += (unsigned long)outcnt;
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outcnt = 0;
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}
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static void error(char *x)
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{
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__putstr(1, "\n\n");
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__putstr(1, x);
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__putstr(1, "\n\n -- System halted");
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while (1)
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asm("hlt");
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}
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static void parse_elf(void *output)
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{
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#ifdef CONFIG_X86_64
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Elf64_Ehdr ehdr;
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Elf64_Phdr *phdrs, *phdr;
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#else
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Elf32_Ehdr ehdr;
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Elf32_Phdr *phdrs, *phdr;
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#endif
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void *dest;
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int i;
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memcpy(&ehdr, output, sizeof(ehdr));
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if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
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ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
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ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
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ehdr.e_ident[EI_MAG3] != ELFMAG3) {
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error("Kernel is not a valid ELF file");
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return;
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}
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if (!quiet)
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putstr("Parsing ELF... ");
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phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
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if (!phdrs)
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error("Failed to allocate space for phdrs");
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memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
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for (i = 0; i < ehdr.e_phnum; i++) {
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phdr = &phdrs[i];
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switch (phdr->p_type) {
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case PT_LOAD:
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#ifdef CONFIG_RELOCATABLE
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dest = output;
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dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
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#else
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dest = (void *)(phdr->p_paddr);
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#endif
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memcpy(dest,
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output + phdr->p_offset,
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phdr->p_filesz);
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break;
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default: /* Ignore other PT_* */ break;
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}
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}
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}
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asmlinkage void decompress_kernel(void *rmode, memptr heap,
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unsigned char *input_data,
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unsigned long input_len,
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unsigned char *output)
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{
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real_mode = rmode;
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if (real_mode->hdr.loadflags & QUIET_FLAG)
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quiet = 1;
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if (real_mode->screen_info.orig_video_mode == 7) {
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vidmem = (char *) 0xb0000;
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vidport = 0x3b4;
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} else {
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vidmem = (char *) 0xb8000;
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vidport = 0x3d4;
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}
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lines = real_mode->screen_info.orig_video_lines;
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cols = real_mode->screen_info.orig_video_cols;
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window = output; /* Output buffer (Normally at 1M) */
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free_mem_ptr = heap; /* Heap */
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free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
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inbuf = input_data; /* Input buffer */
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insize = input_len;
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inptr = 0;
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#ifdef CONFIG_X86_64
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if ((unsigned long)output & (__KERNEL_ALIGN - 1))
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error("Destination address not 2M aligned");
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if ((unsigned long)output >= 0xffffffffffUL)
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error("Destination address too large");
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#else
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if ((u32)output & (CONFIG_PHYSICAL_ALIGN - 1))
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error("Destination address not CONFIG_PHYSICAL_ALIGN aligned");
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if (heap > ((-__PAGE_OFFSET-(512<<20)-1) & 0x7fffffff))
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error("Destination address too large");
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#ifndef CONFIG_RELOCATABLE
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if ((u32)output != LOAD_PHYSICAL_ADDR)
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error("Wrong destination address");
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#endif
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#endif
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makecrc();
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if (!quiet)
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putstr("\nDecompressing Linux... ");
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gunzip();
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parse_elf(output);
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if (!quiet)
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putstr("done.\nBooting the kernel.\n");
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return;
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}
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