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