Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Definitions and wrapper functions for kernel decompressor
3 *
4 * Copyright IBM Corp. 2010
5 *
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7 */
8
9#include <linux/uaccess.h>
10#include <asm/page.h>
11#include <asm/sclp.h>
12#include <asm/ipl.h>
13#include "sizes.h"
14
15/*
16 * gzip declarations
17 */
18#define STATIC static
19
20#undef memset
21#undef memcpy
22#undef memmove
23#define memmove memmove
24#define memzero(s, n) memset((s), 0, (n))
25
26/* Symbols defined by linker scripts */
27extern char input_data[];
28extern int input_len;
29extern char _text, _end;
30extern char _bss, _ebss;
31
32static void error(char *m);
33
34static unsigned long free_mem_ptr;
35static unsigned long free_mem_end_ptr;
36
37#ifdef CONFIG_HAVE_KERNEL_BZIP2
38#define HEAP_SIZE 0x400000
39#else
40#define HEAP_SIZE 0x10000
41#endif
42
43#ifdef CONFIG_KERNEL_GZIP
44#include "../../../../lib/decompress_inflate.c"
45#endif
46
47#ifdef CONFIG_KERNEL_BZIP2
48#include "../../../../lib/decompress_bunzip2.c"
49#endif
50
51#ifdef CONFIG_KERNEL_LZ4
52#include "../../../../lib/decompress_unlz4.c"
53#endif
54
55#ifdef CONFIG_KERNEL_LZMA
56#include "../../../../lib/decompress_unlzma.c"
57#endif
58
59#ifdef CONFIG_KERNEL_LZO
60#include "../../../../lib/decompress_unlzo.c"
61#endif
62
63#ifdef CONFIG_KERNEL_XZ
64#include "../../../../lib/decompress_unxz.c"
65#endif
66
67static int puts(const char *s)
68{
69 sclp_early_printk(s);
70 return 0;
71}
72
73void *memset(void *s, int c, size_t n)
74{
75 char *xs;
76
77 xs = s;
78 while (n--)
79 *xs++ = c;
80 return s;
81}
82
83void *memcpy(void *dest, const void *src, size_t n)
84{
85 const char *s = src;
86 char *d = dest;
87
88 while (n--)
89 *d++ = *s++;
90 return dest;
91}
92
93void *memmove(void *dest, const void *src, size_t n)
94{
95 const char *s = src;
96 char *d = dest;
97
98 if (d <= s) {
99 while (n--)
100 *d++ = *s++;
101 } else {
102 d += n;
103 s += n;
104 while (n--)
105 *--d = *--s;
106 }
107 return dest;
108}
109
110static void error(char *x)
111{
112 unsigned long long psw = 0x000a0000deadbeefULL;
113
114 puts("\n\n");
115 puts(x);
116 puts("\n\n -- System halted");
117
118 asm volatile("lpsw %0" : : "Q" (psw));
119}
120
121/*
122 * Safe guard the ipl parameter block against a memory area that will be
123 * overwritten. The validity check for the ipl parameter block is complex
124 * (see cio_get_iplinfo and ipl_save_parameters) but if the pointer to
125 * the ipl parameter block intersects with the passed memory area we can
126 * safely assume that we can read from that memory. In that case just copy
127 * the memory to IPL_PARMBLOCK_ORIGIN even if there is no ipl parameter
128 * block.
129 */
130static void check_ipl_parmblock(void *start, unsigned long size)
131{
132 void *src, *dst;
133
134 src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
135 if (src + PAGE_SIZE <= start || src >= start + size)
136 return;
137 dst = (void *) IPL_PARMBLOCK_ORIGIN;
138 memmove(dst, src, PAGE_SIZE);
139 S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
140}
141
142unsigned long decompress_kernel(void)
143{
144 void *output, *kernel_end;
145
146 output = (void *) ALIGN((unsigned long) &_end + HEAP_SIZE, PAGE_SIZE);
147 kernel_end = output + SZ__bss_start;
148 check_ipl_parmblock((void *) 0, (unsigned long) kernel_end);
149
150#ifdef CONFIG_BLK_DEV_INITRD
151 /*
152 * Move the initrd right behind the end of the decompressed
153 * kernel image. This also prevents initrd corruption caused by
154 * bss clearing since kernel_end will always be located behind the
155 * current bss section..
156 */
157 if (INITRD_START && INITRD_SIZE && kernel_end > (void *) INITRD_START) {
158 check_ipl_parmblock(kernel_end, INITRD_SIZE);
159 memmove(kernel_end, (void *) INITRD_START, INITRD_SIZE);
160 INITRD_START = (unsigned long) kernel_end;
161 }
162#endif
163
164 /*
165 * Clear bss section. free_mem_ptr and free_mem_end_ptr need to be
166 * initialized afterwards since they reside in bss.
167 */
168 memset(&_bss, 0, &_ebss - &_bss);
169 free_mem_ptr = (unsigned long) &_end;
170 free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
171
172 puts("Uncompressing Linux... ");
173 __decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error);
174 puts("Ok, booting the kernel.\n");
175 return (unsigned long) output;
176}
177