LXR linux/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/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 */
  27extern char input_data[];
  28extern int input_len;
  29extern char _text, _end;
  30extern char _bss, _ebss;
  31
  32static void error(char *m);
  33
  34static unsigned long free_mem_ptr;
  35static 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
  67static int puts(const char *s)
  68{
  69        _sclp_print_early(s);
  70        return 0;
  71}
  72
  73void *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
  83void *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
  93void *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
 110static 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 */
 130static 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
 142unsigned 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
 175