arch/s390/boot/compressed/misc.c

   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
  68 static int puts(const char *s)
  69 {
  70         sclp_early_printk(s);
  71         return 0;
  72 }
  73
  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
  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
  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
 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  */
 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
 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