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 */
112 void *memset(void *s, int c, size_t n);
113 void *memcpy(void *dest, const void *src, size_t n);
118 #define memptr unsigned
121 static memptr free_mem_ptr;
122 static memptr free_mem_end_ptr;
126 static int lines, cols;
128 #ifdef CONFIG_KERNEL_GZIP
129 #include "../../../../lib/decompress_inflate.c"
132 #ifdef CONFIG_KERNEL_BZIP2
133 #include "../../../../lib/decompress_bunzip2.c"
136 #ifdef CONFIG_KERNEL_LZMA
137 #include "../../../../lib/decompress_unlzma.c"
140 #ifdef CONFIG_KERNEL_XZ
141 #include "../../../../lib/decompress_unxz.c"
144 #ifdef CONFIG_KERNEL_LZO
145 #include "../../../../lib/decompress_unlzo.c"
148 static void scroll(void)
152 memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
153 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
159 #define TXR 0 /* Transmit register (WRITE) */
160 #define LSR 5 /* Line Status */
161 static void serial_putchar(int ch)
163 unsigned timeout = 0xffff;
165 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
168 outb(ch, early_serial_base + TXR);
171 void __putstr(const char *s)
176 if (early_serial_base) {
180 serial_putchar('\r');
181 serial_putchar(*str++);
185 if (real_mode->screen_info.orig_video_mode == 0 &&
186 lines == 0 && cols == 0)
189 x = real_mode->screen_info.orig_x;
190 y = real_mode->screen_info.orig_y;
192 while ((c = *s++) != '\0') {
200 vidmem[(x + cols * y) * 2] = c;
211 real_mode->screen_info.orig_x = x;
212 real_mode->screen_info.orig_y = y;
214 pos = (x + cols * y) * 2; /* Update cursor position */
216 outb(0xff & (pos >> 9), vidport+1);
218 outb(0xff & (pos >> 1), vidport+1);
221 void *memset(void *s, int c, size_t n)
226 for (i = 0; i < n; i++)
231 void *memcpy(void *dest, const void *src, size_t n)
238 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
239 : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
245 void *memcpy(void *dest, const void *src, size_t n)
252 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
253 : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
260 static void error(char *x)
262 error_putstr("\n\n");
264 error_putstr("\n\n -- System halted");
270 static void parse_elf(void *output)
274 Elf64_Phdr *phdrs, *phdr;
277 Elf32_Phdr *phdrs, *phdr;
282 memcpy(&ehdr, output, sizeof(ehdr));
283 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
284 ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
285 ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
286 ehdr.e_ident[EI_MAG3] != ELFMAG3) {
287 error("Kernel is not a valid ELF file");
291 debug_putstr("Parsing ELF... ");
293 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
295 error("Failed to allocate space for phdrs");
297 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
299 for (i = 0; i < ehdr.e_phnum; i++) {
302 switch (phdr->p_type) {
304 #ifdef CONFIG_RELOCATABLE
306 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
308 dest = (void *)(phdr->p_paddr);
311 output + phdr->p_offset,
314 default: /* Ignore other PT_* */ break;
321 asmlinkage void decompress_kernel(void *rmode, memptr heap,
322 unsigned char *input_data,
323 unsigned long input_len,
324 unsigned char *output)
328 if (real_mode->screen_info.orig_video_mode == 7) {
329 vidmem = (char *) 0xb0000;
332 vidmem = (char *) 0xb8000;
336 lines = real_mode->screen_info.orig_video_lines;
337 cols = real_mode->screen_info.orig_video_cols;
340 debug_putstr("early console in decompress_kernel\n");
342 free_mem_ptr = heap; /* Heap */
343 free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
345 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
346 error("Destination address inappropriately aligned");
348 if (heap > 0x3fffffffffffUL)
349 error("Destination address too large");
351 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
352 error("Destination address too large");
354 #ifndef CONFIG_RELOCATABLE
355 if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
356 error("Wrong destination address");
359 debug_putstr("\nDecompressing Linux... ");
360 decompress(input_data, input_len, NULL, NULL, output, NULL, error);
362 debug_putstr("done.\nBooting the kernel.\n");