Skip to content
Navigation Menu
Toggle navigation
Sign in
In this repository
All GitHub Enterprise
↵
Jump to
↵
No suggested jump to results
In this repository
All GitHub Enterprise
↵
Jump to
↵
In this organization
All GitHub Enterprise
↵
Jump to
↵
In this repository
All GitHub Enterprise
↵
Jump to
↵
Sign in
Reseting focus
You signed in with another tab or window.
Reload
to refresh your session.
You signed out in another tab or window.
Reload
to refresh your session.
You switched accounts on another tab or window.
Reload
to refresh your session.
Dismiss alert
{{ message }}
mariux64
/
linux
Public
Notifications
You must be signed in to change notification settings
Fork
0
Star
0
Code
Issues
2
Pull requests
0
Actions
Projects
0
Wiki
Security
Insights
Additional navigation options
Code
Issues
Pull requests
Actions
Projects
Wiki
Security
Insights
Files
f47233c
Documentation
arch
alpha
arc
arm
arm64
avr32
blackfin
c6x
cris
frv
hexagon
ia64
m32r
m68k
metag
microblaze
mips
mn10300
nios2
openrisc
parisc
powerpc
s390
score
sh
sparc
tile
um
unicore32
x86
boot
compressed
.gitignore
Makefile
aslr.c
cmdline.c
cpuflags.c
early_serial_console.c
eboot.c
eboot.h
efi_stub_32.S
efi_stub_64.S
head_32.S
head_64.S
misc.c
misc.h
mkpiggy.c
string.c
vmlinux.lds.S
tools
.gitignore
Makefile
a20.c
apm.c
bioscall.S
bitops.h
boot.h
cmdline.c
code16gcc.h
copy.S
cpu.c
cpucheck.c
cpuflags.c
cpuflags.h
ctype.h
early_serial_console.c
edd.c
header.S
install.sh
main.c
mca.c
memory.c
mkcpustr.c
mtools.conf.in
pm.c
pmjump.S
printf.c
regs.c
setup.ld
string.c
string.h
tty.c
version.c
vesa.h
video-bios.c
video-mode.c
video-vesa.c
video-vga.c
video.c
video.h
configs
crypto
ia32
include
kernel
kvm
lguest
lib
math-emu
mm
net
oprofile
pci
platform
power
purgatory
realmode
syscalls
tools
um
vdso
video
xen
.gitignore
Kbuild
Kconfig
Kconfig.cpu
Kconfig.debug
Makefile
Makefile.um
Makefile_32.cpu
xtensa
.gitignore
Kconfig
block
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
README
REPORTING-BUGS
Breadcrumbs
linux
/
arch
/
x86
/
boot
/
compressed
/
misc.c
Blame
Blame
Latest commit
History
History
435 lines (375 loc) · 11.2 KB
Breadcrumbs
linux
/
arch
/
x86
/
boot
/
compressed
/
misc.c
Top
File metadata and controls
Code
Blame
435 lines (375 loc) · 11.2 KB
Raw
/* * misc.c * * This is a collection of several routines from gzip-1.0.3 * adapted for Linux. * * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994 * puts by Nick Holloway 1993, better puts by Martin Mares 1995 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 */ #include "misc.h" #include "../string.h" /* WARNING!! * This code is compiled with -fPIC and it is relocated dynamically * at run time, but no relocation processing is performed. * This means that it is not safe to place pointers in static structures. */ /* * Getting to provable safe in place decompression is hard. * Worst case behaviours need to be analyzed. * Background information: * * The file layout is: * magic[2] * method[1] * flags[1] * timestamp[4] * extraflags[1] * os[1] * compressed data blocks[N] * crc[4] orig_len[4] * * resulting in 18 bytes of non compressed data overhead. * * Files divided into blocks * 1 bit (last block flag) * 2 bits (block type) * * 1 block occurs every 32K -1 bytes or when there 50% compression * has been achieved. The smallest block type encoding is always used. * * stored: * 32 bits length in bytes. * * fixed: * magic fixed tree. * symbols. * * dynamic: * dynamic tree encoding. * symbols. * * * The buffer for decompression in place is the length of the * uncompressed data, plus a small amount extra to keep the algorithm safe. * The compressed data is placed at the end of the buffer. The output * pointer is placed at the start of the buffer and the input pointer * is placed where the compressed data starts. Problems will occur * when the output pointer overruns the input pointer. * * The output pointer can only overrun the input pointer if the input * pointer is moving faster than the output pointer. A condition only * triggered by data whose compressed form is larger than the uncompressed * form. * * The worst case at the block level is a growth of the compressed data * of 5 bytes per 32767 bytes. * * The worst case internal to a compressed block is very hard to figure. * The worst case can at least be boundined by having one bit that represents * 32764 bytes and then all of the rest of the bytes representing the very * very last byte. * * All of which is enough to compute an amount of extra data that is required * to be safe. To avoid problems at the block level allocating 5 extra bytes * per 32767 bytes of data is sufficient. To avoind problems internal to a * block adding an extra 32767 bytes (the worst case uncompressed block size) * is sufficient, to ensure that in the worst case the decompressed data for * block will stop the byte before the compressed data for a block begins. * To avoid problems with the compressed data's meta information an extra 18 * bytes are needed. Leading to the formula: * * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size. * * Adding 8 bytes per 32K is a bit excessive but much easier to calculate. * Adding 32768 instead of 32767 just makes for round numbers. * Adding the decompressor_size is necessary as it musht live after all * of the data as well. Last I measured the decompressor is about 14K. * 10K of actual data and 4K of bss. * */ /* * gzip declarations */ #define STATIC static #undef memcpy /* * Use a normal definition of memset() from string.c. There are already * included header files which expect a definition of memset() and by * the time we define memset macro, it is too late. */ #undef memset #define memzero(s, n) memset((s), 0, (n)) static void error(char *m); /* * This is set up by the setup-routine at boot-time */ struct boot_params *real_mode; /* Pointer to real-mode data */ memptr free_mem_ptr; memptr free_mem_end_ptr; static char *vidmem; static int vidport; static int lines, cols; #ifdef CONFIG_KERNEL_GZIP #include "../../../../lib/decompress_inflate.c" #endif #ifdef CONFIG_KERNEL_BZIP2 #include "../../../../lib/decompress_bunzip2.c" #endif #ifdef CONFIG_KERNEL_LZMA #include "../../../../lib/decompress_unlzma.c" #endif #ifdef CONFIG_KERNEL_XZ #include "../../../../lib/decompress_unxz.c" #endif #ifdef CONFIG_KERNEL_LZO #include "../../../../lib/decompress_unlzo.c" #endif #ifdef CONFIG_KERNEL_LZ4 #include "../../../../lib/decompress_unlz4.c" #endif static void scroll(void) { int i; memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2); for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2) vidmem[i] = ' '; } #define XMTRDY 0x20 #define TXR 0 /* Transmit register (WRITE) */ #define LSR 5 /* Line Status */ static void serial_putchar(int ch) { unsigned timeout = 0xffff; while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout) cpu_relax(); outb(ch, early_serial_base + TXR); } void __putstr(const char *s) { int x, y, pos; char c; if (early_serial_base) { const char *str = s; while (*str) { if (*str == '\n') serial_putchar('\r'); serial_putchar(*str++); } } if (real_mode->screen_info.orig_video_mode == 0 && lines == 0 && cols == 0) return; x = real_mode->screen_info.orig_x; y = real_mode->screen_info.orig_y; while ((c = *s++) != '\0') { if (c == '\n') { x = 0; if (++y >= lines) { scroll(); y--; } } else { vidmem[(x + cols * y) * 2] = c; if (++x >= cols) { x = 0; if (++y >= lines) { scroll(); y--; } } } } real_mode->screen_info.orig_x = x; real_mode->screen_info.orig_y = y; pos = (x + cols * y) * 2; /* Update cursor position */ outb(14, vidport); outb(0xff & (pos >> 9), vidport+1); outb(15, vidport); outb(0xff & (pos >> 1), vidport+1); } static void error(char *x) { error_putstr("\n\n"); error_putstr(x); error_putstr("\n\n -- System halted"); while (1) asm("hlt"); } #if CONFIG_X86_NEED_RELOCS static void handle_relocations(void *output, unsigned long output_len) { int *reloc; unsigned long delta, map, ptr; unsigned long min_addr = (unsigned long)output; unsigned long max_addr = min_addr + output_len; /* * Calculate the delta between where vmlinux was linked to load * and where it was actually loaded. */ delta = min_addr - LOAD_PHYSICAL_ADDR; if (!delta) { debug_putstr("No relocation needed... "); return; } debug_putstr("Performing relocations... "); /* * The kernel contains a table of relocation addresses. Those * addresses have the final load address of the kernel in virtual * memory. We are currently working in the self map. So we need to * create an adjustment for kernel memory addresses to the self map. * This will involve subtracting out the base address of the kernel. */ map = delta - __START_KERNEL_map; /* * Process relocations: 32 bit relocations first then 64 bit after. * Three sets of binary relocations are added to the end of the kernel * before compression. Each relocation table entry is the kernel * address of the location which needs to be updated stored as a * 32-bit value which is sign extended to 64 bits. * * Format is: * * kernel bits... * 0 - zero terminator for 64 bit relocations * 64 bit relocation repeated * 0 - zero terminator for inverse 32 bit relocations * 32 bit inverse relocation repeated * 0 - zero terminator for 32 bit relocations * 32 bit relocation repeated * * So we work backwards from the end of the decompressed image. */ for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) { int extended = *reloc; extended += map; ptr = (unsigned long)extended; if (ptr < min_addr || ptr > max_addr) error("32-bit relocation outside of kernel!\n"); *(uint32_t *)ptr += delta; } #ifdef CONFIG_X86_64 while (*--reloc) { long extended = *reloc; extended += map; ptr = (unsigned long)extended; if (ptr < min_addr || ptr > max_addr) error("inverse 32-bit relocation outside of kernel!\n"); *(int32_t *)ptr -= delta; } for (reloc--; *reloc; reloc--) { long extended = *reloc; extended += map; ptr = (unsigned long)extended; if (ptr < min_addr || ptr > max_addr) error("64-bit relocation outside of kernel!\n"); *(uint64_t *)ptr += delta; } #endif } #else static inline void handle_relocations(void *output, unsigned long output_len) { } #endif static void parse_elf(void *output) { #ifdef CONFIG_X86_64 Elf64_Ehdr ehdr; Elf64_Phdr *phdrs, *phdr; #else Elf32_Ehdr ehdr; Elf32_Phdr *phdrs, *phdr; #endif void *dest; int i; memcpy(&ehdr, output, sizeof(ehdr)); if (ehdr.e_ident[EI_MAG0] != ELFMAG0 || ehdr.e_ident[EI_MAG1] != ELFMAG1 || ehdr.e_ident[EI_MAG2] != ELFMAG2 || ehdr.e_ident[EI_MAG3] != ELFMAG3) { error("Kernel is not a valid ELF file"); return; } debug_putstr("Parsing ELF... "); phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum); if (!phdrs) error("Failed to allocate space for phdrs"); memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum); for (i = 0; i < ehdr.e_phnum; i++) { phdr = &phdrs[i]; switch (phdr->p_type) { case PT_LOAD: #ifdef CONFIG_RELOCATABLE dest = output; dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR); #else dest = (void *)(phdr->p_paddr); #endif memcpy(dest, output + phdr->p_offset, phdr->p_filesz); break; default: /* Ignore other PT_* */ break; } } free(phdrs); } asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap, unsigned char *input_data, unsigned long input_len, unsigned char *output, unsigned long output_len, unsigned long run_size) { unsigned char *output_orig = output; real_mode = rmode; sanitize_boot_params(real_mode); if (real_mode->screen_info.orig_video_mode == 7) { vidmem = (char *) 0xb0000; vidport = 0x3b4; } else { vidmem = (char *) 0xb8000; vidport = 0x3d4; } lines = real_mode->screen_info.orig_video_lines; cols = real_mode->screen_info.orig_video_cols; console_init(); debug_putstr("early console in decompress_kernel\n"); free_mem_ptr = heap; /* Heap */ free_mem_end_ptr = heap + BOOT_HEAP_SIZE; /* * The memory hole needed for the kernel is the larger of either * the entire decompressed kernel plus relocation table, or the * entire decompressed kernel plus .bss and .brk sections. */ output = choose_kernel_location(real_mode, input_data, input_len, output, output_len > run_size ? output_len : run_size); /* Validate memory location choices. */ if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1)) error("Destination address inappropriately aligned"); #ifdef CONFIG_X86_64 if (heap > 0x3fffffffffffUL) error("Destination address too large"); #else if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff)) error("Destination address too large"); #endif #ifndef CONFIG_RELOCATABLE if ((unsigned long)output != LOAD_PHYSICAL_ADDR) error("Wrong destination address"); #endif debug_putstr("\nDecompressing Linux... "); decompress(input_data, input_len, NULL, NULL, output, NULL, error); parse_elf(output); /* * 32-bit always performs relocations. 64-bit relocations are only * needed if kASLR has chosen a different load address. */ if (!IS_ENABLED(CONFIG_X86_64) || output != output_orig) handle_relocations(output, output_len); debug_putstr("done.\nBooting the kernel.\n"); return output; }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
You can’t perform that action at this time.