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 memzero(s, n) memset((s), 0, (n))
  23
  24 /* Symbols defined by linker scripts */
  25 extern char input_data[];
  26 extern int input_len;
  27 extern int _text;
  28 extern int _end;
  29
  30 static void error(char *m);
  31
  32 static unsigned long free_mem_ptr;
  33 static unsigned long free_mem_end_ptr;
  34
  35 #ifdef CONFIG_HAVE_KERNEL_BZIP2
  36 #define HEAP_SIZE       0x400000
  37 #else
  38 #define HEAP_SIZE       0x10000
  39 #endif
  40
  41 #ifdef CONFIG_KERNEL_GZIP
  42 #include "../../../../lib/decompress_inflate.c"
  43 #endif
  44
  45 #ifdef CONFIG_KERNEL_BZIP2
  46 #include "../../../../lib/decompress_bunzip2.c"
  47 #endif
  48
  49 #ifdef CONFIG_KERNEL_LZMA
  50 #include "../../../../lib/decompress_unlzma.c"
  51 #endif
  52
  53 extern _sclp_print_early(const char *);
  54
  55 int puts(const char *s)
  56 {
  57         _sclp_print_early(s);
  58         return 0;
  59 }
  60
  61 void *memset(void *s, int c, size_t n)
  62 {
  63         char *xs;
  64
  65         if (c == 0)
  66                 return __builtin_memset(s, 0, n);
  67
  68         xs = (char *) s;
  69         if (n > 0)
  70                 do {
  71                         *xs++ = c;
  72                 } while (--n > 0);
  73         return s;
  74 }
  75
  76 void *memcpy(void *__dest, __const void *__src, size_t __n)
  77 {
  78         return __builtin_memcpy(__dest, __src, __n);
  79 }
  80
  81 void *memmove(void *__dest, __const void *__src, size_t __n)
  82 {
  83         char *d;
  84         const char *s;
  85
  86         if (__dest <= __src)
  87                 return __builtin_memcpy(__dest, __src, __n);
  88         d = __dest + __n;
  89         s = __src + __n;
  90         while (__n--)
  91                 *--d = *--s;
  92         return __dest;
  93 }
  94
  95 static void error(char *x)
  96 {
  97         unsigned long long psw = 0x000a0000deadbeefULL;
  98
  99         puts("\n\n");
 100         puts(x);
 101         puts("\n\n -- System halted");
 102
 103         asm volatile("lpsw %0" : : "Q" (psw));
 104 }
 105
 106 /*
 107  * Safe guard the ipl parameter block against a memory area that will be
 108  * overwritten. The validity check for the ipl parameter block is complex
 109  * (see cio_get_iplinfo and ipl_save_parameters) but if the pointer to
 110  * the ipl parameter block intersects with the passed memory area we can
 111  * safely assume that we can read from that memory. In that case just copy
 112  * the memory to IPL_PARMBLOCK_ORIGIN even if there is no ipl parameter
 113  * block.
 114  */
 115 static void check_ipl_parmblock(void *start, unsigned long size)
 116 {
 117         void *src, *dst;
 118
 119         src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
 120         if (src + PAGE_SIZE <= start || src >= start + size)
 121                 return;
 122         dst = (void *) IPL_PARMBLOCK_ORIGIN;
 123         memmove(dst, src, PAGE_SIZE);
 124         S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
 125 }
 126
 127 unsigned long decompress_kernel(void)
 128 {
 129         unsigned long output_addr;
 130         unsigned char *output;
 131
 132         free_mem_ptr = (unsigned long)&_end;
 133         free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
 134         output = (unsigned char *) ((free_mem_end_ptr + 4095UL) & -4096UL);
 135
 136         check_ipl_parmblock((void *) 0, (unsigned long) output + SZ__bss_start);
 137
 138 #ifdef CONFIG_BLK_DEV_INITRD
 139         /*
 140          * Move the initrd right behind the end of the decompressed
 141          * kernel image.
 142          */
 143         if (INITRD_START && INITRD_SIZE &&
 144             INITRD_START < (unsigned long) output + SZ__bss_start) {
 145                 check_ipl_parmblock(output + SZ__bss_start,
 146                                     INITRD_START + INITRD_SIZE);
 147                 memmove(output + SZ__bss_start,
 148                         (void *) INITRD_START, INITRD_SIZE);
 149                 INITRD_START = (unsigned long) output + SZ__bss_start;
 150         }
 151 #endif
 152
 153         puts("Uncompressing Linux... ");
 154         decompress(input_data, input_len, NULL, NULL, output, NULL, error);
 155         puts("Ok, booting the kernel.\n");
 156         return (unsigned long) output;
 157 }
 158