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_LZMA
  51 #include "../../../../lib/decompress_unlzma.c"
  52 #endif
  53
  54 #ifdef CONFIG_KERNEL_LZO
  55 #include "../../../../lib/decompress_unlzo.c"
  56 #endif
  57
  58 #ifdef CONFIG_KERNEL_XZ
  59 #include "../../../../lib/decompress_unxz.c"
  60 #endif
  61
  62 extern _sclp_print_early(const char *);
  63
  64 static int puts(const char *s)
  65 {
  66         _sclp_print_early(s);
  67         return 0;
  68 }
  69
  70 void *memset(void *s, int c, size_t n)
  71 {
  72         char *xs;
  73
  74         xs = s;
  75         while (n--)
  76                 *xs++ = c;
  77         return s;
  78 }
  79
  80 void *memcpy(void *dest, const void *src, size_t n)
  81 {
  82         const char *s = src;
  83         char *d = dest;
  84
  85         while (n--)
  86                 *d++ = *s++;
  87         return dest;
  88 }
  89
  90 void *memmove(void *dest, const void *src, size_t n)
  91 {
  92         const char *s = src;
  93         char *d = dest;
  94
  95         if (d <= s) {
  96                 while (n--)
  97                         *d++ = *s++;
  98         } else {
  99                 d += n;
 100                 s += n;
 101                 while (n--)
 102                         *--d = *--s;
 103         }
 104         return dest;
 105 }
 106
 107 static void error(char *x)
 108 {
 109         unsigned long long psw = 0x000a0000deadbeefULL;
 110
 111         puts("\n\n");
 112         puts(x);
 113         puts("\n\n -- System halted");
 114
 115         asm volatile("lpsw %0" : : "Q" (psw));
 116 }
 117
 118 /*
 119  * Safe guard the ipl parameter block against a memory area that will be
 120  * overwritten. The validity check for the ipl parameter block is complex
 121  * (see cio_get_iplinfo and ipl_save_parameters) but if the pointer to
 122  * the ipl parameter block intersects with the passed memory area we can
 123  * safely assume that we can read from that memory. In that case just copy
 124  * the memory to IPL_PARMBLOCK_ORIGIN even if there is no ipl parameter
 125  * block.
 126  */
 127 static void check_ipl_parmblock(void *start, unsigned long size)
 128 {
 129         void *src, *dst;
 130
 131         src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
 132         if (src + PAGE_SIZE <= start || src >= start + size)
 133                 return;
 134         dst = (void *) IPL_PARMBLOCK_ORIGIN;
 135         memmove(dst, src, PAGE_SIZE);
 136         S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
 137 }
 138
 139 unsigned long decompress_kernel(void)
 140 {
 141         unsigned long output_addr;
 142         unsigned char *output;
 143
 144         output_addr = ((unsigned long) &_end + HEAP_SIZE + 4095UL) & -4096UL;
 145         check_ipl_parmblock((void *) 0, output_addr + SZ__bss_start);
 146         memset(&_bss, 0, &_ebss - &_bss);
 147         free_mem_ptr = (unsigned long)&_end;
 148         free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
 149         output = (unsigned char *) output_addr;
 150
 151 #ifdef CONFIG_BLK_DEV_INITRD
 152         /*
 153          * Move the initrd right behind the end of the decompressed
 154          * kernel image.
 155          */
 156         if (INITRD_START && INITRD_SIZE &&
 157             INITRD_START < (unsigned long) output + SZ__bss_start) {
 158                 check_ipl_parmblock(output + SZ__bss_start,
 159                                     INITRD_START + INITRD_SIZE);
 160                 memmove(output + SZ__bss_start,
 161                         (void *) INITRD_START, INITRD_SIZE);
 162                 INITRD_START = (unsigned long) output + SZ__bss_start;
 163         }
 164 #endif
 165
 166         puts("Uncompressing Linux... ");
 167         decompress(input_data, input_len, NULL, NULL, output, NULL, error);
 168         puts("Ok, booting the kernel.\n");
 169         return (unsigned long) output;
 170 }
 171