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 #ifdef CONFIG_KERNEL_LZ4
149 #include "../../../../lib/decompress_unlz4.c"
152 static void scroll(void)
156 memcpy(vidmem
, vidmem
+ cols
* 2, (lines
- 1) * cols
* 2);
157 for (i
= (lines
- 1) * cols
* 2; i
< lines
* cols
* 2; i
+= 2)
163 #define TXR 0 /* Transmit register (WRITE) */
164 #define LSR 5 /* Line Status */
165 static void serial_putchar(int ch
)
167 unsigned timeout
= 0xffff;
169 while ((inb(early_serial_base
+ LSR
) & XMTRDY
) == 0 && --timeout
)
172 outb(ch
, early_serial_base
+ TXR
);
175 void __putstr(const char *s
)
180 if (early_serial_base
) {
184 serial_putchar('\r');
185 serial_putchar(*str
++);
189 if (real_mode
->screen_info
.orig_video_mode
== 0 &&
190 lines
== 0 && cols
== 0)
193 x
= real_mode
->screen_info
.orig_x
;
194 y
= real_mode
->screen_info
.orig_y
;
196 while ((c
= *s
++) != '\0') {
204 vidmem
[(x
+ cols
* y
) * 2] = c
;
215 real_mode
->screen_info
.orig_x
= x
;
216 real_mode
->screen_info
.orig_y
= y
;
218 pos
= (x
+ cols
* y
) * 2; /* Update cursor position */
220 outb(0xff & (pos
>> 9), vidport
+1);
222 outb(0xff & (pos
>> 1), vidport
+1);
225 void *memset(void *s
, int c
, size_t n
)
230 for (i
= 0; i
< n
; i
++)
235 void *memcpy(void *dest
, const void *src
, size_t n
)
242 : "=&c" (d0
), "=&D" (d1
), "=&S" (d2
)
243 : "0" (n
>> 2), "g" (n
& 3), "1" (dest
), "2" (src
)
249 void *memcpy(void *dest
, const void *src
, size_t n
)
256 : "=&c" (d0
), "=&D" (d1
), "=&S" (d2
)
257 : "0" (n
>> 3), "g" (n
& 7), "1" (dest
), "2" (src
)
264 static void error(char *x
)
266 error_putstr("\n\n");
268 error_putstr("\n\n -- System halted");
274 static void parse_elf(void *output
)
278 Elf64_Phdr
*phdrs
, *phdr
;
281 Elf32_Phdr
*phdrs
, *phdr
;
286 memcpy(&ehdr
, output
, sizeof(ehdr
));
287 if (ehdr
.e_ident
[EI_MAG0
] != ELFMAG0
||
288 ehdr
.e_ident
[EI_MAG1
] != ELFMAG1
||
289 ehdr
.e_ident
[EI_MAG2
] != ELFMAG2
||
290 ehdr
.e_ident
[EI_MAG3
] != ELFMAG3
) {
291 error("Kernel is not a valid ELF file");
295 debug_putstr("Parsing ELF... ");
297 phdrs
= malloc(sizeof(*phdrs
) * ehdr
.e_phnum
);
299 error("Failed to allocate space for phdrs");
301 memcpy(phdrs
, output
+ ehdr
.e_phoff
, sizeof(*phdrs
) * ehdr
.e_phnum
);
303 for (i
= 0; i
< ehdr
.e_phnum
; i
++) {
306 switch (phdr
->p_type
) {
308 #ifdef CONFIG_RELOCATABLE
310 dest
+= (phdr
->p_paddr
- LOAD_PHYSICAL_ADDR
);
312 dest
= (void *)(phdr
->p_paddr
);
315 output
+ phdr
->p_offset
,
318 default: /* Ignore other PT_* */ break;
325 asmlinkage
void decompress_kernel(void *rmode
, memptr heap
,
326 unsigned char *input_data
,
327 unsigned long input_len
,
328 unsigned char *output
)
332 sanitize_boot_params(real_mode
);
334 if (real_mode
->screen_info
.orig_video_mode
== 7) {
335 vidmem
= (char *) 0xb0000;
338 vidmem
= (char *) 0xb8000;
342 lines
= real_mode
->screen_info
.orig_video_lines
;
343 cols
= real_mode
->screen_info
.orig_video_cols
;
346 debug_putstr("early console in decompress_kernel\n");
348 free_mem_ptr
= heap
; /* Heap */
349 free_mem_end_ptr
= heap
+ BOOT_HEAP_SIZE
;
351 if ((unsigned long)output
& (MIN_KERNEL_ALIGN
- 1))
352 error("Destination address inappropriately aligned");
354 if (heap
> 0x3fffffffffffUL
)
355 error("Destination address too large");
357 if (heap
> ((-__PAGE_OFFSET
-(128<<20)-1) & 0x7fffffff))
358 error("Destination address too large");
360 #ifndef CONFIG_RELOCATABLE
361 if ((unsigned long)output
!= LOAD_PHYSICAL_ADDR
)
362 error("Wrong destination address");
365 debug_putstr("\nDecompressing Linux... ");
366 decompress(input_data
, input_len
, NULL
, NULL
, output
, NULL
, error
);
368 debug_putstr("done.\nBooting the kernel.\n");