4 * This is a collection of several routines from gzip-1.0.3
7 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
8 * puts by Nick Holloway 1993, better puts by Martin Mares 1995
9 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
15 * This code is compiled with -fPIC and it is relocated dynamically
16 * at run time, but no relocation processing is performed.
17 * This means that it is not safe to place pointers in static structures.
21 * Getting to provable safe in place decompression is hard.
22 * Worst case behaviours need to be analyzed.
23 * Background information:
32 * compressed data blocks[N]
35 * resulting in 18 bytes of non compressed data overhead.
37 * Files divided into blocks
38 * 1 bit (last block flag)
41 * 1 block occurs every 32K -1 bytes or when there 50% compression
42 * has been achieved. The smallest block type encoding is always used.
45 * 32 bits length in bytes.
52 * dynamic tree encoding.
56 * The buffer for decompression in place is the length of the
57 * uncompressed data, plus a small amount extra to keep the algorithm safe.
58 * The compressed data is placed at the end of the buffer. The output
59 * pointer is placed at the start of the buffer and the input pointer
60 * is placed where the compressed data starts. Problems will occur
61 * when the output pointer overruns the input pointer.
63 * The output pointer can only overrun the input pointer if the input
64 * pointer is moving faster than the output pointer. A condition only
65 * triggered by data whose compressed form is larger than the uncompressed
68 * The worst case at the block level is a growth of the compressed data
69 * of 5 bytes per 32767 bytes.
71 * The worst case internal to a compressed block is very hard to figure.
72 * The worst case can at least be boundined by having one bit that represents
73 * 32764 bytes and then all of the rest of the bytes representing the very
76 * All of which is enough to compute an amount of extra data that is required
77 * to be safe. To avoid problems at the block level allocating 5 extra bytes
78 * per 32767 bytes of data is sufficient. To avoind problems internal to a
79 * block adding an extra 32767 bytes (the worst case uncompressed block size)
80 * is sufficient, to ensure that in the worst case the decompressed data for
81 * block will stop the byte before the compressed data for a block begins.
82 * To avoid problems with the compressed data's meta information an extra 18
83 * bytes are needed. Leading to the formula:
85 * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
87 * Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
88 * Adding 32768 instead of 32767 just makes for round numbers.
89 * Adding the decompressor_size is necessary as it musht live after all
90 * of the data as well. Last I measured the decompressor is about 14K.
91 * 10K of actual data and 4K of bss.
102 #define memzero(s, n) memset((s), 0, (n))
105 static void error(char *m);
108 * This is set up by the setup-routine at boot-time
110 struct boot_params *real_mode; /* Pointer to real-mode data */
114 void *memset(void *s, int c, size_t n);
115 void *memcpy(void *dest, const void *src, size_t n);
120 #define memptr unsigned
123 static memptr free_mem_ptr;
124 static memptr free_mem_end_ptr;
128 static int lines, cols;
130 #ifdef CONFIG_KERNEL_GZIP
131 #include "../../../../lib/decompress_inflate.c"
134 #ifdef CONFIG_KERNEL_BZIP2
135 #include "../../../../lib/decompress_bunzip2.c"
138 #ifdef CONFIG_KERNEL_LZMA
139 #include "../../../../lib/decompress_unlzma.c"
142 #ifdef CONFIG_KERNEL_XZ
143 #include "../../../../lib/decompress_unxz.c"
146 #ifdef CONFIG_KERNEL_LZO
147 #include "../../../../lib/decompress_unlzo.c"
150 static void scroll(void)
154 memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
155 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
161 #define TXR 0 /* Transmit register (WRITE) */
162 #define LSR 5 /* Line Status */
163 static void serial_putchar(int ch)
165 unsigned timeout = 0xffff;
167 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
170 outb(ch, early_serial_base + TXR);
173 void __putstr(int error, const char *s)
178 #ifndef CONFIG_X86_VERBOSE_BOOTUP
182 if (early_serial_base) {
186 serial_putchar('\r');
187 serial_putchar(*str++);
191 if (real_mode->screen_info.orig_video_mode == 0 &&
192 lines == 0 && cols == 0)
195 x = real_mode->screen_info.orig_x;
196 y = real_mode->screen_info.orig_y;
198 while ((c = *s++) != '\0') {
206 vidmem[(x + cols * y) * 2] = c;
217 real_mode->screen_info.orig_x = x;
218 real_mode->screen_info.orig_y = y;
220 pos = (x + cols * y) * 2; /* Update cursor position */
222 outb(0xff & (pos >> 9), vidport+1);
224 outb(0xff & (pos >> 1), vidport+1);
227 void *memset(void *s, int c, size_t n)
232 for (i = 0; i < n; i++)
237 void *memcpy(void *dest, const void *src, size_t n)
244 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
245 : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
251 void *memcpy(void *dest, const void *src, size_t n)
258 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
259 : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
266 static void error(char *x)
270 __putstr(1, "\n\n -- System halted");
276 static void parse_elf(void *output)
280 Elf64_Phdr *phdrs, *phdr;
283 Elf32_Phdr *phdrs, *phdr;
288 memcpy(&ehdr, output, sizeof(ehdr));
289 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
290 ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
291 ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
292 ehdr.e_ident[EI_MAG3] != ELFMAG3) {
293 error("Kernel is not a valid ELF file");
298 putstr("Parsing ELF... ");
300 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
302 error("Failed to allocate space for phdrs");
304 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
306 for (i = 0; i < ehdr.e_phnum; i++) {
309 switch (phdr->p_type) {
311 #ifdef CONFIG_RELOCATABLE
313 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
315 dest = (void *)(phdr->p_paddr);
318 output + phdr->p_offset,
321 default: /* Ignore other PT_* */ break;
326 asmlinkage void decompress_kernel(void *rmode, memptr heap,
327 unsigned char *input_data,
328 unsigned long input_len,
329 unsigned char *output)
333 if (cmdline_find_option_bool("quiet"))
335 if (cmdline_find_option_bool("debug"))
338 if (real_mode->screen_info.orig_video_mode == 7) {
339 vidmem = (char *) 0xb0000;
342 vidmem = (char *) 0xb8000;
346 lines = real_mode->screen_info.orig_video_lines;
347 cols = real_mode->screen_info.orig_video_cols;
351 putstr("early console in decompress_kernel\n");
353 free_mem_ptr = heap; /* Heap */
354 free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
356 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
357 error("Destination address inappropriately aligned");
359 if (heap > 0x3fffffffffffUL)
360 error("Destination address too large");
362 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
363 error("Destination address too large");
365 #ifndef CONFIG_RELOCATABLE
366 if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
367 error("Wrong destination address");
371 putstr("\nDecompressing Linux... ");
372 decompress(input_data, input_len, NULL, NULL, output, NULL, error);
375 putstr("done.\nBooting the kernel.\n");