arch/s390/boot/compressed/misc.c

   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 <asm/uaccess.h>
  10 #include <asm/page.h>
  11 #include <asm/ipl.h>
  12 #include "sizes.h"
  13
  14 /*
  15  * gzip declarations
  16  */
  17 #define STATIC static
  18
  19 #undef memset
  20 #undef memcpy
  21 #undef memmove
  22 #define memmove memmove
  23 #define memzero(s, n) memset((s), 0, (n))
  24
  25 /* Symbols defined by linker scripts */
  26 extern char input_data[];
  27 extern int input_len;
  28 extern char _text, _end;
  29 extern char _bss, _ebss;
  30
  31 static void error(char *m);
  32
  33 static unsigned long free_mem_ptr;
  34 static unsigned long free_mem_end_ptr;
  35
  36 #ifdef CONFIG_HAVE_KERNEL_BZIP2
  37 #define HEAP_SIZE       0x400000
  38 #else
  39 #define HEAP_SIZE       0x10000
  40 #endif
  41
  42 #ifdef CONFIG_KERNEL_GZIP
  43 #include "../../../../lib/decompress_inflate.c"
  44 #endif
  45
  46 #ifdef CONFIG_KERNEL_BZIP2
  47 #include "../../../../lib/decompress_bunzip2.c"
  48 #endif
  49
  50 #ifdef CONFIG_KERNEL_LZ4
  51 #include "../../../../lib/decompress_unlz4.c"
  52 #endif
  53
  54 #ifdef CONFIG_KERNEL_LZMA
  55 #include "../../../../lib/decompress_unlzma.c"
  56 #endif
  57
  58 #ifdef CONFIG_KERNEL_LZO
  59 #include "../../../../lib/decompress_unlzo.c"
  60 #endif
  61
  62 #ifdef CONFIG_KERNEL_XZ
  63 #include "../../../../lib/decompress_unxz.c"
  64 #endif
  65
  66 extern _sclp_print_early(const char *);
  67
  68 static int puts(const char *s)
  69 {
  70         _sclp_print_early(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         unsigned long output_addr;
 146         unsigned char *output;
 147
 148         output_addr = ((unsigned long) &_end + HEAP_SIZE + 4095UL) & -4096UL;
 149         check_ipl_parmblock((void *) 0, output_addr + SZ__bss_start);
 150         memset(&_bss, 0, &_ebss - &_bss);
 151         free_mem_ptr = (unsigned long)&_end;
 152         free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
 153         output = (unsigned char *) output_addr;
 154
 155 #ifdef CONFIG_BLK_DEV_INITRD
 156         /*
 157          * Move the initrd right behind the end of the decompressed
 158          * kernel image.
 159          */
 160         if (INITRD_START && INITRD_SIZE &&
 161             INITRD_START < (unsigned long) output + SZ__bss_start) {
 162                 check_ipl_parmblock(output + SZ__bss_start,
 163                                     INITRD_START + INITRD_SIZE);
 164                 memmove(output + SZ__bss_start,
 165                         (void *) INITRD_START, INITRD_SIZE);
 166                 INITRD_START = (unsigned long) output + SZ__bss_start;
 167         }
 168 #endif
 169
 170         puts("Uncompressing Linux... ");
 171         decompress(input_data, input_len, NULL, NULL, output, NULL, error);
 172         puts("Ok, booting the kernel.\n");
 173         return (unsigned long) output;
 174 }
 175