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);
116 memptr free_mem_end_ptr;
120 static int lines, cols;
122 #ifdef CONFIG_KERNEL_GZIP
123 #include "../../../../lib/decompress_inflate.c"
126 #ifdef CONFIG_KERNEL_BZIP2
127 #include "../../../../lib/decompress_bunzip2.c"
130 #ifdef CONFIG_KERNEL_LZMA
131 #include "../../../../lib/decompress_unlzma.c"
134 #ifdef CONFIG_KERNEL_XZ
135 #include "../../../../lib/decompress_unxz.c"
138 #ifdef CONFIG_KERNEL_LZO
139 #include "../../../../lib/decompress_unlzo.c"
142 #ifdef CONFIG_KERNEL_LZ4
143 #include "../../../../lib/decompress_unlz4.c"
146 static void scroll(void)
150 memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
151 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
157 #define TXR 0 /* Transmit register (WRITE) */
158 #define LSR 5 /* Line Status */
159 static void serial_putchar(int ch)
161 unsigned timeout = 0xffff;
163 while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
166 outb(ch, early_serial_base + TXR);
169 void __putstr(const char *s)
174 if (early_serial_base) {
178 serial_putchar('\r');
179 serial_putchar(*str++);
183 if (real_mode->screen_info.orig_video_mode == 0 &&
184 lines == 0 && cols == 0)
187 x = real_mode->screen_info.orig_x;
188 y = real_mode->screen_info.orig_y;
190 while ((c = *s++) != '\0') {
198 vidmem[(x + cols * y) * 2] = c;
209 real_mode->screen_info.orig_x = x;
210 real_mode->screen_info.orig_y = y;
212 pos = (x + cols * y) * 2; /* Update cursor position */
214 outb(0xff & (pos >> 9), vidport+1);
216 outb(0xff & (pos >> 1), vidport+1);
219 void *memset(void *s, int c, size_t n)
224 for (i = 0; i < n; i++)
229 void *memcpy(void *dest, const void *src, size_t n)
236 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
237 : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
243 void *memcpy(void *dest, const void *src, size_t n)
250 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
251 : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
258 static void error(char *x)
260 error_putstr("\n\n");
262 error_putstr("\n\n -- System halted");
268 #if CONFIG_X86_NEED_RELOCS
269 static void handle_relocations(void *output, unsigned long output_len)
272 unsigned long delta, map, ptr;
273 unsigned long min_addr = (unsigned long)output;
274 unsigned long max_addr = min_addr + output_len;
277 * Calculate the delta between where vmlinux was linked to load
278 * and where it was actually loaded.
280 delta = min_addr - LOAD_PHYSICAL_ADDR;
282 debug_putstr("No relocation needed... ");
285 debug_putstr("Performing relocations... ");
288 * The kernel contains a table of relocation addresses. Those
289 * addresses have the final load address of the kernel in virtual
290 * memory. We are currently working in the self map. So we need to
291 * create an adjustment for kernel memory addresses to the self map.
292 * This will involve subtracting out the base address of the kernel.
294 map = delta - __START_KERNEL_map;
297 * Process relocations: 32 bit relocations first then 64 bit after.
298 * Two sets of binary relocations are added to the end of the kernel
299 * before compression. Each relocation table entry is the kernel
300 * address of the location which needs to be updated stored as a
301 * 32-bit value which is sign extended to 64 bits.
306 * 0 - zero terminator for 64 bit relocations
307 * 64 bit relocation repeated
308 * 0 - zero terminator for 32 bit relocations
309 * 32 bit relocation repeated
311 * So we work backwards from the end of the decompressed image.
313 for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) {
314 int extended = *reloc;
317 ptr = (unsigned long)extended;
318 if (ptr < min_addr || ptr > max_addr)
319 error("32-bit relocation outside of kernel!\n");
321 *(uint32_t *)ptr += delta;
324 for (reloc--; *reloc; reloc--) {
325 long extended = *reloc;
328 ptr = (unsigned long)extended;
329 if (ptr < min_addr || ptr > max_addr)
330 error("64-bit relocation outside of kernel!\n");
332 *(uint64_t *)ptr += delta;
337 static inline void handle_relocations(void *output, unsigned long output_len)
341 static void parse_elf(void *output)
345 Elf64_Phdr *phdrs, *phdr;
348 Elf32_Phdr *phdrs, *phdr;
353 memcpy(&ehdr, output, sizeof(ehdr));
354 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
355 ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
356 ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
357 ehdr.e_ident[EI_MAG3] != ELFMAG3) {
358 error("Kernel is not a valid ELF file");
362 debug_putstr("Parsing ELF... ");
364 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
366 error("Failed to allocate space for phdrs");
368 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
370 for (i = 0; i < ehdr.e_phnum; i++) {
373 switch (phdr->p_type) {
375 #ifdef CONFIG_RELOCATABLE
377 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
379 dest = (void *)(phdr->p_paddr);
382 output + phdr->p_offset,
385 default: /* Ignore other PT_* */ break;
392 asmlinkage void *decompress_kernel(void *rmode, memptr heap,
393 unsigned char *input_data,
394 unsigned long input_len,
395 unsigned char *output,
396 unsigned long output_len)
400 sanitize_boot_params(real_mode);
402 if (real_mode->screen_info.orig_video_mode == 7) {
403 vidmem = (char *) 0xb0000;
406 vidmem = (char *) 0xb8000;
410 lines = real_mode->screen_info.orig_video_lines;
411 cols = real_mode->screen_info.orig_video_cols;
414 debug_putstr("early console in decompress_kernel\n");
416 free_mem_ptr = heap; /* Heap */
417 free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
419 output = choose_kernel_location(input_data, input_len,
422 /* Validate memory location choices. */
423 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
424 error("Destination address inappropriately aligned");
426 if (heap > 0x3fffffffffffUL)
427 error("Destination address too large");
429 if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
430 error("Destination address too large");
432 #ifndef CONFIG_RELOCATABLE
433 if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
434 error("Wrong destination address");
437 debug_putstr("\nDecompressing Linux... ");
438 decompress(input_data, input_len, NULL, NULL, output, NULL, error);
440 handle_relocations(output, output_len);
441 debug_putstr("done.\nBooting the kernel.\n");