378 lines
8.8 KiB
C
378 lines
8.8 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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#include "misc.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 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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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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struct boot_params *real_mode; /* Pointer to real-mode data */
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static int quiet;
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static int debug;
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void *memset(void *s, int c, size_t n);
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void *memcpy(void *dest, const void *src, size_t n);
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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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#ifdef CONFIG_KERNEL_GZIP
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#include "../../../../lib/decompress_inflate.c"
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#endif
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#ifdef CONFIG_KERNEL_BZIP2
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#include "../../../../lib/decompress_bunzip2.c"
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#endif
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#ifdef CONFIG_KERNEL_LZMA
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#include "../../../../lib/decompress_unlzma.c"
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#endif
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#ifdef CONFIG_KERNEL_XZ
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#include "../../../../lib/decompress_unxz.c"
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#endif
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#ifdef CONFIG_KERNEL_LZO
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#include "../../../../lib/decompress_unlzo.c"
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#endif
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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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#define XMTRDY 0x20
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#define TXR 0 /* Transmit register (WRITE) */
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#define LSR 5 /* Line Status */
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static void serial_putchar(int ch)
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{
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unsigned timeout = 0xffff;
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while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
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cpu_relax();
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outb(ch, early_serial_base + TXR);
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}
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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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if (early_serial_base) {
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const char *str = s;
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while (*str) {
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if (*str == '\n')
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serial_putchar('\r');
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serial_putchar(*str++);
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}
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}
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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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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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void *memset(void *s, int c, size_t 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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#ifdef CONFIG_X86_32
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void *memcpy(void *dest, const void *src, size_t n)
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{
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int d0, d1, d2;
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asm volatile(
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"rep ; movsl\n\t"
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"movl %4,%%ecx\n\t"
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"rep ; movsb\n\t"
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: "=&c" (d0), "=&D" (d1), "=&S" (d2)
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: "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
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: "memory");
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return dest;
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}
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#else
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void *memcpy(void *dest, const void *src, size_t n)
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{
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long d0, d1, d2;
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asm volatile(
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"rep ; movsq\n\t"
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"movq %4,%%rcx\n\t"
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"rep ; movsb\n\t"
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: "=&c" (d0), "=&D" (d1), "=&S" (d2)
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: "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
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: "memory");
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return dest;
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}
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#endif
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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 (cmdline_find_option_bool("quiet"))
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quiet = 1;
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if (cmdline_find_option_bool("debug"))
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debug = 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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console_init();
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if (debug)
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putstr("early console in decompress_kernel\n");
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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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if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
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error("Destination address inappropriately aligned");
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#ifdef CONFIG_X86_64
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if (heap > 0x3fffffffffffUL)
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error("Destination address too large");
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#else
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if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
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error("Destination address too large");
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#endif
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#ifndef CONFIG_RELOCATABLE
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if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
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error("Wrong destination address");
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#endif
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if (!quiet)
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putstr("\nDecompressing Linux... ");
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decompress(input_data, input_len, NULL, NULL, output, NULL, error);
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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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