LXR linux/arch/s390/boot/compressed/misc.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Definitions and wrapper functions for kernel decompressor
   4 *
   5 * Copyright IBM Corp. 2010
   6 *
   7 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   8 */
   9
  10#include <linux/uaccess.h>
  11#include <asm/page.h>
  12#include <asm/sclp.h>
  13#include <asm/ipl.h>
  14#include "sizes.h"
  15
  16/*
  17 * gzip declarations
  18 */
  19#define STATIC static
  20
  21#undef memset
  22#undef memcpy
  23#undef memmove
  24#define memmove memmove
  25#define memzero(s, n) memset((s), 0, (n))
  26
  27/* Symbols defined by linker scripts */
  28extern char input_data[];
  29extern int input_len;
  30extern char _text, _end;
  31extern char _bss, _ebss;
  32
  33static void error(char *m);
  34
  35static unsigned long free_mem_ptr;
  36static unsigned long free_mem_end_ptr;
  37
  38#ifdef CONFIG_HAVE_KERNEL_BZIP2
  39#define HEAP_SIZE       0x400000
  40#else
  41#define HEAP_SIZE       0x10000
  42#endif
  43
  44#ifdef CONFIG_KERNEL_GZIP
  45#include "../../../../lib/decompress_inflate.c"
  46#endif
  47
  48#ifdef CONFIG_KERNEL_BZIP2
  49#include "../../../../lib/decompress_bunzip2.c"
  50#endif
  51
  52#ifdef CONFIG_KERNEL_LZ4
  53#include "../../../../lib/decompress_unlz4.c"
  54#endif
  55
  56#ifdef CONFIG_KERNEL_LZMA
  57#include "../../../../lib/decompress_unlzma.c"
  58#endif
  59
  60#ifdef CONFIG_KERNEL_LZO
  61#include "../../../../lib/decompress_unlzo.c"
  62#endif
  63
  64#ifdef CONFIG_KERNEL_XZ
  65#include "../../../../lib/decompress_unxz.c"
  66#endif
  67
  68static int puts(const char *s)
  69{
  70        sclp_early_printk(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        void *output, *kernel_end;
 146
 147        output = (void *) ALIGN((unsigned long) &_end + HEAP_SIZE, PAGE_SIZE);
 148        kernel_end = output + SZ__bss_start;
 149        check_ipl_parmblock((void *) 0, (unsigned long) kernel_end);
 150
 151#ifdef CONFIG_BLK_DEV_INITRD
 152        /*
 153         * Move the initrd right behind the end of the decompressed
 154         * kernel image. This also prevents initrd corruption caused by
 155         * bss clearing since kernel_end will always be located behind the
 156         * current bss section..
 157         */
 158        if (INITRD_START && INITRD_SIZE && kernel_end > (void *) INITRD_START) {
 159                check_ipl_parmblock(kernel_end, INITRD_SIZE);
 160                memmove(kernel_end, (void *) INITRD_START, INITRD_SIZE);
 161                INITRD_START = (unsigned long) kernel_end;
 162        }
 163#endif
 164
 165        /*
 166         * Clear bss section. free_mem_ptr and free_mem_end_ptr need to be
 167         * initialized afterwards since they reside in bss.
 168         */
 169        memset(&_bss, 0, &_ebss - &_bss);
 170        free_mem_ptr = (unsigned long) &_end;
 171        free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
 172
 173        __decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error);
 174        return (unsigned long) output;
 175}
 176
 177