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