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 */
113 void *memset(void *s, int c, size_t n);
114 void *memcpy(void *dest, const void *src, size_t n);
119 #define memptr unsigned
122 static memptr free_mem_ptr;
123 static memptr free_mem_end_ptr;
127 static int lines, cols;
129 #ifdef CONFIG_KERNEL_GZIP
130 #include "../../../../lib/decompress_inflate.c"
133 #ifdef CONFIG_KERNEL_BZIP2
134 #include "../../../../lib/decompress_bunzip2.c"
137 #ifdef CONFIG_KERNEL_LZMA
138 #include "../../../../lib/decompress_unlzma.c"
141 #ifdef CONFIG_KERNEL_XZ
142 #include "../../../../lib/decompress_unxz.c"
145 #ifdef CONFIG_KERNEL_LZO
146 #include "../../../../lib/decompress_unlzo.c"
149 static void scroll(void)
153 memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
154 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
160 #define TXR 0 /* Transmit register (WRITE) */
161 #define LSR 5 /* Line Status */
162 static void serial_putchar(int ch)
164 unsigned timeout = 0xffff;
166 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
169 outb(ch, early_serial_base + TXR);
172 void __putstr(int error, const char *s)
177 #ifndef CONFIG_X86_VERBOSE_BOOTUP
181 if (early_serial_base) {
185 serial_putchar('\r');
186 serial_putchar(*str++);
190 if (real_mode->screen_info.orig_video_mode == 0 &&
191 lines == 0 && cols == 0)
194 x = real_mode->screen_info.orig_x;
195 y = real_mode->screen_info.orig_y;
197 while ((c = *s++) != '\0') {
205 vidmem[(x + cols * y) * 2] = c;
216 real_mode->screen_info.orig_x = x;
217 real_mode->screen_info.orig_y = y;
219 pos = (x + cols * y) * 2; /* Update cursor position */
221 outb(0xff & (pos >> 9), vidport+1);
223 outb(0xff & (pos >> 1), vidport+1);
226 void *memset(void *s, int c, size_t n)
231 for (i = 0; i < n; i++)
236 void *memcpy(void *dest, const void *src, size_t n)
243 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
244 : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
250 void *memcpy(void *dest, const void *src, size_t n)
257 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
258 : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
265 static void error(char *x)
269 __putstr(1, "\n\n -- System halted");
275 static void parse_elf(void *output)
279 Elf64_Phdr *phdrs, *phdr;
282 Elf32_Phdr *phdrs, *phdr;
287 memcpy(&ehdr, output, sizeof(ehdr));
288 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
289 ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
290 ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
291 ehdr.e_ident[EI_MAG3] != ELFMAG3) {
292 error("Kernel is not a valid ELF file");
297 putstr("Parsing ELF... ");
299 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
301 error("Failed to allocate space for phdrs");
303 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
305 for (i = 0; i < ehdr.e_phnum; i++) {
308 switch (phdr->p_type) {
310 #ifdef CONFIG_RELOCATABLE
312 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
314 dest = (void *)(phdr->p_paddr);
317 output + phdr->p_offset,
320 default: /* Ignore other PT_* */ break;
327 asmlinkage void decompress_kernel(void *rmode, memptr heap,
328 unsigned char *input_data,
329 unsigned long input_len,
330 unsigned char *output)
334 if (cmdline_find_option_bool("debug"))
337 if (real_mode->screen_info.orig_video_mode == 7) {
338 vidmem = (char *) 0xb0000;
341 vidmem = (char *) 0xb8000;
345 lines = real_mode->screen_info.orig_video_lines;
346 cols = real_mode->screen_info.orig_video_cols;
350 putstr("early console in decompress_kernel\n");
352 free_mem_ptr = heap; /* Heap */
353 free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
355 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
356 error("Destination address inappropriately aligned");
358 if (heap > 0x3fffffffffffUL)
359 error("Destination address too large");
361 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
362 error("Destination address too large");
364 #ifndef CONFIG_RELOCATABLE
365 if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
366 error("Wrong destination address");
370 putstr("\nDecompressing Linux... ");
371 decompress(input_data, input_len, NULL, NULL, output, NULL, error);
374 putstr("done.\nBooting the kernel.\n");