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/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 */
  26extern char input_data[];
  27extern int input_len;
  28extern char _text, _end;
  29extern char _bss, _ebss;
  30
  31static void error(char *m);
  32
  33static unsigned long free_mem_ptr;
  34static 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_LZ4
  51#include "../../../../lib/decompress_unlz4.c"
  52#endif
  53
  54#ifdef CONFIG_KERNEL_LZMA
  55#include "../../../../lib/decompress_unlzma.c"
  56#endif
  57
  58#ifdef CONFIG_KERNEL_LZO
  59#include "../../../../lib/decompress_unlzo.c"
  60#endif
  61
  62#ifdef CONFIG_KERNEL_XZ
  63#include "../../../../lib/decompress_unxz.c"
  64#endif
  65
  66extern _sclp_print_early(const char *);
  67
  68static int puts(const char *s)
  69{
  70        _sclp_print_early(s);
  71        return 0;
  72}
  73
  74void *memset(void *s, int c, size_t n)
  75{
  76        char *xs;
  77
  78        xs = s;
  79        while (n--)
  80                *xs++ = c;
  81        return s;
  82}
  83
  84void *memcpy(void *dest, const void *src, size_t n)
  85{
  86        const char *s = src;
  87        char *d = dest;
  88
  89        while (n--)
  90                *d++ = *s++;
  91        return dest;
  92}
  93
  94void *memmove(void *dest, const void *src, size_t n)
  95{
  96        const char *s = src;
  97        char *d = dest;
  98
  99        if (d <= s) {
 100                while (n--)
 101                        *d++ = *s++;
 102        } else {
 103                d += n;
 104                s += n;
 105                while (n--)
 106                        *--d = *--s;
 107        }
 108        return dest;
 109}
 110
 111static void error(char *x)
 112{
 113        unsigned long long psw = 0x000a0000deadbeefULL;
 114
 115        puts("\n\n");
 116        puts(x);
 117        puts("\n\n -- System halted");
 118
 119        asm volatile("lpsw %0" : : "Q" (psw));
 120}
 121
 122/*
 123 * Safe guard the ipl parameter block against a memory area that will be
 124 * overwritten. The validity check for the ipl parameter block is complex
 125 * (see cio_get_iplinfo and ipl_save_parameters) but if the pointer to
 126 * the ipl parameter block intersects with the passed memory area we can
 127 * safely assume that we can read from that memory. In that case just copy
 128 * the memory to IPL_PARMBLOCK_ORIGIN even if there is no ipl parameter
 129 * block.
 130 */
 131static void check_ipl_parmblock(void *start, unsigned long size)
 132{
 133        void *src, *dst;
 134
 135        src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
 136        if (src + PAGE_SIZE <= start || src >= start + size)
 137                return;
 138        dst = (void *) IPL_PARMBLOCK_ORIGIN;
 139        memmove(dst, src, PAGE_SIZE);
 140        S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
 141}
 142
 143unsigned long decompress_kernel(void)
 144{
 145        unsigned long output_addr;
 146        unsigned char *output;
 147
 148        output_addr = ((unsigned long) &_end + HEAP_SIZE + 4095UL) & -4096UL;
 149        check_ipl_parmblock((void *) 0, output_addr + SZ__bss_start);
 150        memset(&_bss, 0, &_ebss - &_bss);
 151        free_mem_ptr = (unsigned long)&_end;
 152        free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
 153        output = (unsigned char *) output_addr;
 154
 155#ifdef CONFIG_BLK_DEV_INITRD
 156        /*
 157         * Move the initrd right behind the end of the decompressed
 158         * kernel image.
 159         */
 160        if (INITRD_START && INITRD_SIZE &&
 161            INITRD_START < (unsigned long) output + SZ__bss_start) {
 162                check_ipl_parmblock(output + SZ__bss_start,
 163                                    INITRD_START + INITRD_SIZE);
 164                memmove(output + SZ__bss_start,
 165                        (void *) INITRD_START, INITRD_SIZE);
 166                INITRD_START = (unsigned long) output + SZ__bss_start;
 167        }
 168#endif
 169
 170        puts("Uncompressing Linux... ");
 171        decompress(input_data, input_len, NULL, NULL, output, NULL, error);
 172        puts("Ok, booting the kernel.\n");
 173        return (unsigned long) output;
 174}
 175
 176