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Diffstat (limited to 'arch/x86_64/boot/compressed/misc_64.c')
| -rw-r--r-- | arch/x86_64/boot/compressed/misc_64.c | 371 |
1 files changed, 371 insertions, 0 deletions
diff --git a/arch/x86_64/boot/compressed/misc_64.c b/arch/x86_64/boot/compressed/misc_64.c new file mode 100644 index 000000000000..f932b0e89096 --- /dev/null +++ b/arch/x86_64/boot/compressed/misc_64.c @@ -0,0 +1,371 @@ +/* + * misc.c + * + * This is a collection of several routines from gzip-1.0.3 + * adapted for Linux. + * + * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994 + * puts by Nick Holloway 1993, better puts by Martin Mares 1995 + * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 + */ + +#define _LINUX_STRING_H_ 1 +#define __LINUX_BITMAP_H 1 + +#include <linux/linkage.h> +#include <linux/screen_info.h> +#include <asm/io.h> +#include <asm/page.h> + +/* WARNING!! + * This code is compiled with -fPIC and it is relocated dynamically + * at run time, but no relocation processing is performed. + * This means that it is not safe to place pointers in static structures. + */ + +/* + * Getting to provable safe in place decompression is hard. + * Worst case behaviours need to be analized. + * Background information: + * + * The file layout is: + * magic[2] + * method[1] + * flags[1] + * timestamp[4] + * extraflags[1] + * os[1] + * compressed data blocks[N] + * crc[4] orig_len[4] + * + * resulting in 18 bytes of non compressed data overhead. + * + * Files divided into blocks + * 1 bit (last block flag) + * 2 bits (block type) + * + * 1 block occurs every 32K -1 bytes or when there 50% compression has been achieved. + * The smallest block type encoding is always used. + * + * stored: + * 32 bits length in bytes. + * + * fixed: + * magic fixed tree. + * symbols. + * + * dynamic: + * dynamic tree encoding. + * symbols. + * + * + * The buffer for decompression in place is the length of the + * uncompressed data, plus a small amount extra to keep the algorithm safe. + * The compressed data is placed at the end of the buffer. The output + * pointer is placed at the start of the buffer and the input pointer + * is placed where the compressed data starts. Problems will occur + * when the output pointer overruns the input pointer. + * + * The output pointer can only overrun the input pointer if the input + * pointer is moving faster than the output pointer. A condition only + * triggered by data whose compressed form is larger than the uncompressed + * form. + * + * The worst case at the block level is a growth of the compressed data + * of 5 bytes per 32767 bytes. + * + * The worst case internal to a compressed block is very hard to figure. + * The worst case can at least be boundined by having one bit that represents + * 32764 bytes and then all of the rest of the bytes representing the very + * very last byte. + * + * All of which is enough to compute an amount of extra data that is required + * to be safe. To avoid problems at the block level allocating 5 extra bytes + * per 32767 bytes of data is sufficient. To avoind problems internal to a block + * adding an extra 32767 bytes (the worst case uncompressed block size) is + * sufficient, to ensure that in the worst case the decompressed data for + * block will stop the byte before the compressed data for a block begins. + * To avoid problems with the compressed data's meta information an extra 18 + * bytes are needed. Leading to the formula: + * + * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size. + * + * Adding 8 bytes per 32K is a bit excessive but much easier to calculate. + * Adding 32768 instead of 32767 just makes for round numbers. + * Adding the decompressor_size is necessary as it musht live after all + * of the data as well. Last I measured the decompressor is about 14K. + * 10K of actuall data and 4K of bss. + * + */ + +/* + * gzip declarations + */ + +#define OF(args) args +#define STATIC static + +#undef memset +#undef memcpy +#define memzero(s, n) memset ((s), 0, (n)) + +typedef unsigned char uch; +typedef unsigned short ush; +typedef unsigned long ulg; + +#define WSIZE 0x80000000 /* Window size must be at least 32k, + * and a power of two + * We don't actually have a window just + * a huge output buffer so I report + * a 2G windows size, as that should + * always be larger than our output buffer. + */ + +static uch *inbuf; /* input buffer */ +static uch *window; /* Sliding window buffer, (and final output buffer) */ + +static unsigned insize; /* valid bytes in inbuf */ +static unsigned inptr; /* index of next byte to be processed in inbuf */ +static unsigned outcnt; /* bytes in output buffer */ + +/* gzip flag byte */ +#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ +#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ +#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ +#define ORIG_NAME 0x08 /* bit 3 set: original file name present */ +#define COMMENT 0x10 /* bit 4 set: file comment present */ +#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ +#define RESERVED 0xC0 /* bit 6,7: reserved */ + +#define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf()) + +/* Diagnostic functions */ +#ifdef DEBUG +# define Assert(cond,msg) {if(!(cond)) error(msg);} +# define Trace(x) fprintf x +# define Tracev(x) {if (verbose) fprintf x ;} +# define Tracevv(x) {if (verbose>1) fprintf x ;} +# define Tracec(c,x) {if (verbose && (c)) fprintf x ;} +# define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;} +#else +# define Assert(cond,msg) +# define Trace(x) +# define Tracev(x) +# define Tracevv(x) +# define Tracec(c,x) +# define Tracecv(c,x) +#endif + +static int fill_inbuf(void); +static void flush_window(void); +static void error(char *m); +static void gzip_mark(void **); +static void gzip_release(void **); + +/* + * This is set up by the setup-routine at boot-time + */ +static unsigned char *real_mode; /* Pointer to real-mode data */ + +#define RM_EXT_MEM_K (*(unsigned short *)(real_mode + 0x2)) +#ifndef STANDARD_MEMORY_BIOS_CALL +#define RM_ALT_MEM_K (*(unsigned long *)(real_mode + 0x1e0)) +#endif +#define RM_SCREEN_INFO (*(struct screen_info *)(real_mode+0)) + +extern unsigned char input_data[]; +extern int input_len; + +static long bytes_out = 0; + +static void *malloc(int size); +static void free(void *where); + +static void *memset(void *s, int c, unsigned n); +static void *memcpy(void *dest, const void *src, unsigned n); + +static void putstr(const char *); + +static long free_mem_ptr; +static long free_mem_end_ptr; + +#define HEAP_SIZE 0x7000 + +static char *vidmem = (char *)0xb8000; +static int vidport; +static int lines, cols; + +#include "../../../../lib/inflate.c" + +static void *malloc(int size) +{ + void *p; + + if (size <0) error("Malloc error"); + if (free_mem_ptr <= 0) error("Memory error"); + + free_mem_ptr = (free_mem_ptr + 3) & ~3; /* Align */ + + p = (void *)free_mem_ptr; + free_mem_ptr += size; + + if (free_mem_ptr >= free_mem_end_ptr) + error("Out of memory"); + + return p; +} + +static void free(void *where) +{ /* Don't care */ +} + +static void gzip_mark(void **ptr) +{ + *ptr = (void *) free_mem_ptr; +} + +static void gzip_release(void **ptr) +{ + free_mem_ptr = (long) *ptr; +} + +static void scroll(void) +{ + int i; + + memcpy ( vidmem, vidmem + cols * 2, ( lines - 1 ) * cols * 2 ); + for ( i = ( lines - 1 ) * cols * 2; i < lines * cols * 2; i += 2 ) + vidmem[i] = ' '; +} + +static void putstr(const char *s) +{ + int x,y,pos; + char c; + + x = RM_SCREEN_INFO.orig_x; + y = RM_SCREEN_INFO.orig_y; + + while ( ( c = *s++ ) != '\0' ) { + if ( c == '\n' ) { + x = 0; + if ( ++y >= lines ) { + scroll(); + y--; + } + } else { + vidmem [ ( x + cols * y ) * 2 ] = c; + if ( ++x >= cols ) { + x = 0; + if ( ++y >= lines ) { + scroll(); + y--; + } + } + } + } + + RM_SCREEN_INFO.orig_x = x; + RM_SCREEN_INFO.orig_y = y; + + pos = (x + cols * y) * 2; /* Update cursor position */ + outb_p(14, vidport); + outb_p(0xff & (pos >> 9), vidport+1); + outb_p(15, vidport); + outb_p(0xff & (pos >> 1), vidport+1); +} + +static void* memset(void* s, int c, unsigned n) +{ + int i; + char *ss = (char*)s; + + for (i=0;i<n;i++) ss[i] = c; + return s; +} + +static void* memcpy(void* dest, const void* src, unsigned n) +{ + int i; + char *d = (char *)dest, *s = (char *)src; + + for (i=0;i<n;i++) d[i] = s[i]; + return dest; +} + +/* =========================================================================== + * Fill the input buffer. This is called only when the buffer is empty + * and at least one byte is really needed. + */ +static int fill_inbuf(void) +{ + error("ran out of input data"); + return 0; +} + +/* =========================================================================== + * Write the output window window[0..outcnt-1] and update crc and bytes_out. + * (Used for the decompressed data only.) + */ +static void flush_window(void) +{ + /* With my window equal to my output buffer + * I only need to compute the crc here. + */ + ulg c = crc; /* temporary variable */ + unsigned n; + uch *in, ch; + + in = window; + for (n = 0; n < outcnt; n++) { + ch = *in++; + c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8); + } + crc = c; + bytes_out += (ulg)outcnt; + outcnt = 0; +} + +static void error(char *x) +{ + putstr("\n\n"); + putstr(x); + putstr("\n\n -- System halted"); + + while(1); /* Halt */ +} + +asmlinkage void decompress_kernel(void *rmode, unsigned long heap, + uch *input_data, unsigned long input_len, uch *output) +{ + real_mode = rmode; + + if (RM_SCREEN_INFO.orig_video_mode == 7) { + vidmem = (char *) 0xb0000; + vidport = 0x3b4; + } else { + vidmem = (char *) 0xb8000; + vidport = 0x3d4; + } + + lines = RM_SCREEN_INFO.orig_video_lines; + cols = RM_SCREEN_INFO.orig_video_cols; + + window = output; /* Output buffer (Normally at 1M) */ + free_mem_ptr = heap; /* Heap */ + free_mem_end_ptr = heap + HEAP_SIZE; + inbuf = input_data; /* Input buffer */ + insize = input_len; + inptr = 0; + + if ((ulg)output & (__KERNEL_ALIGN - 1)) + error("Destination address not 2M aligned"); + if ((ulg)output >= 0xffffffffffUL) + error("Destination address too large"); + + makecrc(); + putstr(".\nDecompressing Linux..."); + gunzip(); + putstr("done.\nBooting the kernel.\n"); + return; +} |
