676b1855de
Spelling fixes in arch/x86_64/. Signed-off-by: Simon Arlott <simon@fire.lp0.eu> Signed-off-by: Adrian Bunk <bunk@kernel.org>
372 lines
9.5 KiB
C
372 lines
9.5 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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#define _LINUX_STRING_H_ 1
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#define __LINUX_BITMAP_H 1
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#include <linux/linkage.h>
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#include <linux/screen_info.h>
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#include <asm/io.h>
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#include <asm/page.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 has been achieved.
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* 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 block
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* adding an extra 32767 bytes (the worst case uncompressed block size) is
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* 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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#define WSIZE 0x80000000 /* Window size must be at least 32k,
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* and a power of two
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* We don't actually have a window just
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* a huge output buffer so I report
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* a 2G windows size, as that should
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* always be larger than our output buffer.
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*/
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static uch *inbuf; /* input buffer */
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static uch *window; /* Sliding window buffer, (and final output buffer) */
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static unsigned insize; /* valid bytes in inbuf */
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static unsigned inptr; /* index of next byte to be processed in inbuf */
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static unsigned outcnt; /* bytes in output buffer */
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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 gzip file */
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#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
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#define ORIG_NAME 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) {if(!(cond)) error(msg);}
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# define Trace(x) fprintf x
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# define Tracev(x) {if (verbose) fprintf x ;}
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# define Tracevv(x) {if (verbose>1) fprintf x ;}
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# define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
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# define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
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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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static void gzip_mark(void **);
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static void gzip_release(void **);
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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 unsigned char *real_mode; /* Pointer to real-mode data */
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#define RM_EXT_MEM_K (*(unsigned short *)(real_mode + 0x2))
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#ifndef STANDARD_MEMORY_BIOS_CALL
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#define RM_ALT_MEM_K (*(unsigned long *)(real_mode + 0x1e0))
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#endif
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#define RM_SCREEN_INFO (*(struct screen_info *)(real_mode+0))
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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 = 0;
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static void *malloc(int size);
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static void free(void *where);
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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(const char *);
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static long free_mem_ptr;
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static long free_mem_end_ptr;
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#define HEAP_SIZE 0x7000
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static char *vidmem = (char *)0xb8000;
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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 *malloc(int size)
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{
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void *p;
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if (size <0) error("Malloc error");
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if (free_mem_ptr <= 0) error("Memory error");
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free_mem_ptr = (free_mem_ptr + 3) & ~3; /* Align */
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p = (void *)free_mem_ptr;
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free_mem_ptr += size;
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if (free_mem_ptr >= free_mem_end_ptr)
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error("Out of memory");
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return p;
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}
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static void free(void *where)
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{ /* Don't care */
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}
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static void gzip_mark(void **ptr)
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{
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*ptr = (void *) free_mem_ptr;
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}
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static void gzip_release(void **ptr)
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{
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free_mem_ptr = (long) *ptr;
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}
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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(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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x = RM_SCREEN_INFO.orig_x;
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y = RM_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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RM_SCREEN_INFO.orig_x = x;
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RM_SCREEN_INFO.orig_y = y;
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pos = (x + cols * y) * 2; /* Update cursor position */
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outb_p(14, vidport);
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outb_p(0xff & (pos >> 9), vidport+1);
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outb_p(15, vidport);
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outb_p(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 = (char*)s;
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for (i=0;i<n;i++) 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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char *d = (char *)dest, *s = (char *)src;
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for (i=0;i<n;i++) 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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ulg c = crc; /* temporary variable */
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unsigned n;
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uch *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 += (ulg)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("\n\n");
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putstr(x);
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putstr("\n\n -- System halted");
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while(1); /* Halt */
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}
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asmlinkage void decompress_kernel(void *rmode, unsigned long heap,
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uch *input_data, unsigned long input_len, uch *output)
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{
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real_mode = rmode;
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if (RM_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 = RM_SCREEN_INFO.orig_video_lines;
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cols = RM_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 + 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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if ((ulg)output & (__KERNEL_ALIGN - 1))
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error("Destination address not 2M aligned");
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if ((ulg)output >= 0xffffffffffUL)
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error("Destination address too large");
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makecrc();
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putstr(".\nDecompressing Linux...");
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gunzip();
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putstr("done.\nBooting the kernel.\n");
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return;
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}
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