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 <linux/uaccess.h>
  10 #include <asm/page.h>
  11 #include <asm/sclp.h>
  12 #include <asm/ipl.h>
  13 #include "sizes.h"
  14
  15 /*
  16  * gzip declarations
  17  */
  18 #define STATIC static
  19
  20 #undef memset
  21 #undef memcpy
  22 #undef memmove
  23 #define memmove memmove
  24 #define memzero(s, n) memset((s), 0, (n))
  25
  26 /* Symbols defined by linker scripts */
  27 extern char input_data[];
  28 extern int input_len;
  29 extern char _text, _end;
  30 extern char _bss, _ebss;
  31
  32 static void error(char *m);
  33
  34 static unsigned long free_mem_ptr;
  35 static unsigned long free_mem_end_ptr;
  36
  37 #ifdef CONFIG_HAVE_KERNEL_BZIP2
  38 #define HEAP_SIZE       0x400000
  39 #else
  40 #define HEAP_SIZE       0x10000
  41 #endif
  42
  43 #ifdef CONFIG_KERNEL_GZIP
  44 #include "../../../../lib/decompress_inflate.c"
  45 #endif
  46
  47 #ifdef CONFIG_KERNEL_BZIP2
  48 #include "../../../../lib/decompress_bunzip2.c"
  49 #endif
  50
  51 #ifdef CONFIG_KERNEL_LZ4
  52 #include "../../../../lib/decompress_unlz4.c"
  53 #endif
  54
  55 #ifdef CONFIG_KERNEL_LZMA
  56 #include "../../../../lib/decompress_unlzma.c"
  57 #endif
  58
  59 #ifdef CONFIG_KERNEL_LZO
  60 #include "../../../../lib/decompress_unlzo.c"
  61 #endif
  62
  63 #ifdef CONFIG_KERNEL_XZ
  64 #include "../../../../lib/decompress_unxz.c"
  65 #endif
  66
  67 static int puts(const char *s)
  68 {
  69         sclp_early_printk(s);
  70         return 0;
  71 }
  72
  73 void *memset(void *s, int c, size_t n)
  74 {
  75         char *xs;
  76
  77         xs = s;
  78         while (n--)
  79                 *xs++ = c;
  80         return s;
  81 }
  82
  83 void *memcpy(void *dest, const void *src, size_t n)
  84 {
  85         const char *s = src;
  86         char *d = dest;
  87
  88         while (n--)
  89                 *d++ = *s++;
  90         return dest;
  91 }
  92
  93 void *memmove(void *dest, const void *src, size_t n)
  94 {
  95         const char *s = src;
  96         char *d = dest;
  97
  98         if (d <= s) {
  99                 while (n--)
 100                         *d++ = *s++;
 101         } else {
 102                 d += n;
 103                 s += n;
 104                 while (n--)
 105                         *--d = *--s;
 106         }
 107         return dest;
 108 }
 109
 110 static void error(char *x)
 111 {
 112         unsigned long long psw = 0x000a0000deadbeefULL;
 113
 114         puts("\n\n");
 115         puts(x);
 116         puts("\n\n -- System halted");
 117
 118         asm volatile("lpsw %0" : : "Q" (psw));
 119 }
 120
 121 /*
 122  * Safe guard the ipl parameter block against a memory area that will be
 123  * overwritten. The validity check for the ipl parameter block is complex
 124  * (see cio_get_iplinfo and ipl_save_parameters) but if the pointer to
 125  * the ipl parameter block intersects with the passed memory area we can
 126  * safely assume that we can read from that memory. In that case just copy
 127  * the memory to IPL_PARMBLOCK_ORIGIN even if there is no ipl parameter
 128  * block.
 129  */
 130 static void check_ipl_parmblock(void *start, unsigned long size)
 131 {
 132         void *src, *dst;
 133
 134         src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
 135         if (src + PAGE_SIZE <= start || src >= start + size)
 136                 return;
 137         dst = (void *) IPL_PARMBLOCK_ORIGIN;
 138         memmove(dst, src, PAGE_SIZE);
 139         S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
 140 }
 141
 142 unsigned long decompress_kernel(void)
 143 {
 144         unsigned long output_addr;
 145         unsigned char *output;
 146
 147         output_addr = ((unsigned long) &_end + HEAP_SIZE + 4095UL) & -4096UL;
 148         check_ipl_parmblock((void *) 0, output_addr + SZ__bss_start);
 149         memset(&_bss, 0, &_ebss - &_bss);
 150         free_mem_ptr = (unsigned long)&_end;
 151         free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
 152         output = (unsigned char *) output_addr;
 153
 154 #ifdef CONFIG_BLK_DEV_INITRD
 155         /*
 156          * Move the initrd right behind the end of the decompressed
 157          * kernel image.
 158          */
 159         if (INITRD_START && INITRD_SIZE &&
 160             INITRD_START < (unsigned long) output + SZ__bss_start) {
 161                 check_ipl_parmblock(output + SZ__bss_start,
 162                                     INITRD_START + INITRD_SIZE);
 163                 memmove(output + SZ__bss_start,
 164                         (void *) INITRD_START, INITRD_SIZE);
 165                 INITRD_START = (unsigned long) output + SZ__bss_start;
 166         }
 167 #endif
 168
 169         puts("Uncompressing Linux... ");
 170         __decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error);
 171         puts("Ok, booting the kernel.\n");
 172         return (unsigned long) output;
 173 }
 174