Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Definitions and wrapper functions for kernel decompressor
4 *
5 * Copyright IBM Corp. 2010
6 *
7 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
8 */
9
10#include <linux/uaccess.h>
11#include <asm/page.h>
12#include <asm/sclp.h>
13#include <asm/ipl.h>
14#include "sizes.h"
15
16/*
17 * gzip declarations
18 */
19#define STATIC static
20
21#undef memset
22#undef memcpy
23#undef memmove
24#define memmove memmove
25#define memzero(s, n) memset((s), 0, (n))
26
27/* Symbols defined by linker scripts */
28extern char input_data[];
29extern int input_len;
30extern char _text, _end;
31extern char _bss, _ebss;
32
33static void error(char *m);
34
35static unsigned long free_mem_ptr;
36static unsigned long free_mem_end_ptr;
37
38#ifdef CONFIG_HAVE_KERNEL_BZIP2
39#define HEAP_SIZE 0x400000
40#else
41#define HEAP_SIZE 0x10000
42#endif
43
44#ifdef CONFIG_KERNEL_GZIP
45#include "../../../../lib/decompress_inflate.c"
46#endif
47
48#ifdef CONFIG_KERNEL_BZIP2
49#include "../../../../lib/decompress_bunzip2.c"
50#endif
51
52#ifdef CONFIG_KERNEL_LZ4
53#include "../../../../lib/decompress_unlz4.c"
54#endif
55
56#ifdef CONFIG_KERNEL_LZMA
57#include "../../../../lib/decompress_unlzma.c"
58#endif
59
60#ifdef CONFIG_KERNEL_LZO
61#include "../../../../lib/decompress_unlzo.c"
62#endif
63
64#ifdef CONFIG_KERNEL_XZ
65#include "../../../../lib/decompress_unxz.c"
66#endif
67
68static int puts(const char *s)
69{
70 sclp_early_printk(s);
71 return 0;
72}
73
74void *memset(void *s, int c, size_t n)
75{
76 char *xs;
77
78 xs = s;
79 while (n--)
80 *xs++ = c;
81 return s;
82}
83
84void *memcpy(void *dest, const void *src, size_t n)
85{
86 const char *s = src;
87 char *d = dest;
88
89 while (n--)
90 *d++ = *s++;
91 return dest;
92}
93
94void *memmove(void *dest, const void *src, size_t n)
95{
96 const char *s = src;
97 char *d = dest;
98
99 if (d <= s) {
100 while (n--)
101 *d++ = *s++;
102 } else {
103 d += n;
104 s += n;
105 while (n--)
106 *--d = *--s;
107 }
108 return dest;
109}
110
111static void error(char *x)
112{
113 unsigned long long psw = 0x000a0000deadbeefULL;
114
115 puts("\n\n");
116 puts(x);
117 puts("\n\n -- System halted");
118
119 asm volatile("lpsw %0" : : "Q" (psw));
120}
121
122/*
123 * Safe guard the ipl parameter block against a memory area that will be
124 * overwritten. The validity check for the ipl parameter block is complex
125 * (see cio_get_iplinfo and ipl_save_parameters) but if the pointer to
126 * the ipl parameter block intersects with the passed memory area we can
127 * safely assume that we can read from that memory. In that case just copy
128 * the memory to IPL_PARMBLOCK_ORIGIN even if there is no ipl parameter
129 * block.
130 */
131static void check_ipl_parmblock(void *start, unsigned long size)
132{
133 void *src, *dst;
134
135 src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
136 if (src + PAGE_SIZE <= start || src >= start + size)
137 return;
138 dst = (void *) IPL_PARMBLOCK_ORIGIN;
139 memmove(dst, src, PAGE_SIZE);
140 S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
141}
142
143unsigned long decompress_kernel(void)
144{
145 void *output, *kernel_end;
146
147 output = (void *) ALIGN((unsigned long) &_end + HEAP_SIZE, PAGE_SIZE);
148 kernel_end = output + SZ__bss_start;
149 check_ipl_parmblock((void *) 0, (unsigned long) kernel_end);
150
151#ifdef CONFIG_BLK_DEV_INITRD
152 /*
153 * Move the initrd right behind the end of the decompressed
154 * kernel image. This also prevents initrd corruption caused by
155 * bss clearing since kernel_end will always be located behind the
156 * current bss section..
157 */
158 if (INITRD_START && INITRD_SIZE && kernel_end > (void *) INITRD_START) {
159 check_ipl_parmblock(kernel_end, INITRD_SIZE);
160 memmove(kernel_end, (void *) INITRD_START, INITRD_SIZE);
161 INITRD_START = (unsigned long) kernel_end;
162 }
163#endif
164
165 /*
166 * Clear bss section. free_mem_ptr and free_mem_end_ptr need to be
167 * initialized afterwards since they reside in bss.
168 */
169 memset(&_bss, 0, &_ebss - &_bss);
170 free_mem_ptr = (unsigned long) &_end;
171 free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
172
173 __decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error);
174 return (unsigned long) output;
175}
176