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 */
28 extern char input_data[];
29 extern int input_len;
30 extern char _text, _end;
31 extern char _bss, _ebss;
32
33 static void error(char *m);
34
35 static unsigned long free_mem_ptr;
36 static 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
puts(const char * s)68 static int puts(const char *s)
69 {
70 sclp_early_printk(s);
71 return 0;
72 }
73
memset(void * s,int c,size_t n)74 void *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
memcpy(void * dest,const void * src,size_t n)84 void *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
memmove(void * dest,const void * src,size_t n)94 void *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
error(char * x)111 static 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 */
check_ipl_parmblock(void * start,unsigned long size)131 static 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
decompress_kernel(void)143 unsigned 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 puts("Uncompressing Linux... ");
174 __decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error);
175 puts("Ok, booting the kernel.\n");
176 return (unsigned long) output;
177 }
178
179