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
13 * we have to be careful, because no indirections are allowed here, and
14 * paravirt_ops is a kind of one. As it will only run in baremetal anyway,
15 * we just keep it from happening
17 #undef CONFIG_PARAVIRT
19 #define _ASM_X86_DESC_H 1
22 #include <linux/linkage.h>
23 #include <linux/screen_info.h>
24 #include <linux/elf.h>
28 #include <asm/bootparam.h>
31 * This code is compiled with -fPIC and it is relocated dynamically
32 * at run time, but no relocation processing is performed.
33 * This means that it is not safe to place pointers in static structures.
37 * Getting to provable safe in place decompression is hard.
38 * Worst case behaviours need to be analyzed.
39 * Background information:
48 * compressed data blocks[N]
51 * resulting in 18 bytes of non compressed data overhead.
53 * Files divided into blocks
54 * 1 bit (last block flag)
57 * 1 block occurs every 32K -1 bytes or when there 50% compression
58 * has been achieved. The smallest block type encoding is always used.
61 * 32 bits length in bytes.
68 * dynamic tree encoding.
72 * The buffer for decompression in place is the length of the
73 * uncompressed data, plus a small amount extra to keep the algorithm safe.
74 * The compressed data is placed at the end of the buffer. The output
75 * pointer is placed at the start of the buffer and the input pointer
76 * is placed where the compressed data starts. Problems will occur
77 * when the output pointer overruns the input pointer.
79 * The output pointer can only overrun the input pointer if the input
80 * pointer is moving faster than the output pointer. A condition only
81 * triggered by data whose compressed form is larger than the uncompressed
84 * The worst case at the block level is a growth of the compressed data
85 * of 5 bytes per 32767 bytes.
87 * The worst case internal to a compressed block is very hard to figure.
88 * The worst case can at least be boundined by having one bit that represents
89 * 32764 bytes and then all of the rest of the bytes representing the very
92 * All of which is enough to compute an amount of extra data that is required
93 * to be safe. To avoid problems at the block level allocating 5 extra bytes
94 * per 32767 bytes of data is sufficient. To avoind problems internal to a
95 * block adding an extra 32767 bytes (the worst case uncompressed block size)
96 * is sufficient, to ensure that in the worst case the decompressed data for
97 * block will stop the byte before the compressed data for a block begins.
98 * To avoid problems with the compressed data's meta information an extra 18
99 * bytes are needed. Leading to the formula:
101 * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size.
103 * Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
104 * Adding 32768 instead of 32767 just makes for round numbers.
105 * Adding the decompressor_size is necessary as it musht live after all
106 * of the data as well. Last I measured the decompressor is about 14K.
107 * 10K of actual data and 4K of bss.
114 #define STATIC static
118 #define memzero(s, n) memset((s), 0, (n))
121 static void error(char *m);
124 * This is set up by the setup-routine at boot-time
126 static struct boot_params *real_mode; /* Pointer to real-mode data */
129 void *memset(void *s, int c, size_t n);
130 void *memcpy(void *dest, const void *src, size_t n);
132 static void __putstr(int, const char *);
133 #define putstr(__x) __putstr(0, __x)
138 #define memptr unsigned
141 static memptr free_mem_ptr;
142 static memptr free_mem_end_ptr;
146 static int lines, cols;
148 #ifdef CONFIG_KERNEL_GZIP
149 #include "../../../../lib/decompress_inflate.c"
152 #ifdef CONFIG_KERNEL_BZIP2
153 #include "../../../../lib/decompress_bunzip2.c"
156 #ifdef CONFIG_KERNEL_LZMA
157 #include "../../../../lib/decompress_unlzma.c"
160 #ifdef CONFIG_KERNEL_LZO
161 #include "../../../../lib/decompress_unlzo.c"
164 static void scroll(void)
168 memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
169 for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
173 static void __putstr(int error, const char *s)
178 #ifndef CONFIG_X86_VERBOSE_BOOTUP
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)
235 for (i = 0; i < n; i++)
241 static void error(char *x)
245 __putstr(1, "\n\n -- System halted");
251 static void parse_elf(void *output)
255 Elf64_Phdr *phdrs, *phdr;
258 Elf32_Phdr *phdrs, *phdr;
263 memcpy(&ehdr, output, sizeof(ehdr));
264 if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
265 ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
266 ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
267 ehdr.e_ident[EI_MAG3] != ELFMAG3) {
268 error("Kernel is not a valid ELF file");
273 putstr("Parsing ELF... ");
275 phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
277 error("Failed to allocate space for phdrs");
279 memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
281 for (i = 0; i < ehdr.e_phnum; i++) {
284 switch (phdr->p_type) {
286 #ifdef CONFIG_RELOCATABLE
288 dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
290 dest = (void *)(phdr->p_paddr);
293 output + phdr->p_offset,
296 default: /* Ignore other PT_* */ break;
301 asmlinkage void decompress_kernel(void *rmode, memptr heap,
302 unsigned char *input_data,
303 unsigned long input_len,
304 unsigned char *output)
308 if (real_mode->hdr.loadflags & QUIET_FLAG)
311 if (real_mode->screen_info.orig_video_mode == 7) {
312 vidmem = (char *) 0xb0000;
315 vidmem = (char *) 0xb8000;
319 lines = real_mode->screen_info.orig_video_lines;
320 cols = real_mode->screen_info.orig_video_cols;
322 free_mem_ptr = heap; /* Heap */
323 free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
325 if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
326 error("Destination address inappropriately aligned");
328 if (heap > 0x3fffffffffffUL)
329 error("Destination address too large");
331 if (heap > ((-__PAGE_OFFSET-(512<<20)-1) & 0x7fffffff))
332 error("Destination address too large");
334 #ifndef CONFIG_RELOCATABLE
335 if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
336 error("Wrong destination address");
340 putstr("\nDecompressing Linux... ");
341 decompress(input_data, input_len, NULL, NULL, output, NULL, error);
344 putstr("done.\nBooting the kernel.\n");