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