misc.c

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/*
 * Definitions and wrapper functions for kernel decompressor
 *
 * Copyright IBM Corp. 2010
 *
 * Author(s): Martin Schwidefsky <[email protected]>
 */

#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/ipl.h>
#include "sizes.h"

/*
 * gzip declarations
 */
#define STATIC static

#undef memset
#undef memcpy
#undef memmove
#define memmove memmove
#define memzero(s, n) memset((s), 0, (n))

/* Symbols defined by linker scripts */
extern char input_data[];
extern int input_len;
extern char _text, _end;
extern char _bss, _ebss;

static void error(char *m);

static unsigned long free_mem_ptr;
static unsigned long free_mem_end_ptr;

#ifdef CONFIG_HAVE_KERNEL_BZIP2
#define HEAP_SIZE   0x400000
#else
#define HEAP_SIZE   0x10000
#endif

#ifdef CONFIG_KERNEL_GZIP
#include "../../../../lib/decompress_inflate.c"
#endif

#ifdef CONFIG_KERNEL_BZIP2
#include "../../../../lib/decompress_bunzip2.c"
#endif

#ifdef CONFIG_KERNEL_LZMA
#include "../../../../lib/decompress_unlzma.c"
#endif

#ifdef CONFIG_KERNEL_LZO
#include "../../../../lib/decompress_unlzo.c"
#endif

#ifdef CONFIG_KERNEL_XZ
#include "../../../../lib/decompress_unxz.c"
#endif

extern _sclp_print_early(const char *);

static int puts(const char *s)
{
    _sclp_print_early(s);
    return 0;
}

void *memset(void *s, int c, size_t n)
{
    char *xs;

    xs = s;
    while (n--)
        *xs++ = c;
    return s;
}

void *memcpy(void *dest, const void *src, size_t n)
{
    const char *s = src;
    char *d = dest;

    while (n--)
        *d++ = *s++;
    return dest;
}

void *memmove(void *dest, const void *src, size_t n)
{
    const char *s = src;
    char *d = dest;

    if (d <= s) {
        while (n--)
            *d++ = *s++;
    } else {
        d += n;
        s += n;
        while (n--)
            *--d = *--s;
    }
    return dest;
}

static void error(char *x)
{
    unsigned long long psw = 0x000a0000deadbeefULL;

    puts("\n\n");
    puts(x);
    puts("\n\n -- System halted");

    asm volatile("lpsw %0" : : "Q" (psw));
}

/*
 * Safe guard the ipl parameter block against a memory area that will be
 * overwritten. The validity check for the ipl parameter block is complex
 * (see cio_get_iplinfo and ipl_save_parameters) but if the pointer to
 * the ipl parameter block intersects with the passed memory area we can
 * safely assume that we can read from that memory. In that case just copy
 * the memory to IPL_PARMBLOCK_ORIGIN even if there is no ipl parameter
 * block.
 */
static void check_ipl_parmblock(void *start, unsigned long size)
{
    void *src, *dst;

    src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
    if (src + PAGE_SIZE <= start || src >= start + size)
        return;
    dst = (void *) IPL_PARMBLOCK_ORIGIN;
    memmove(dst, src, PAGE_SIZE);
    S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
}

unsigned long decompress_kernel(void)
{
    unsigned long output_addr;
    unsigned char *output;

    output_addr = ((unsigned long) &_end + HEAP_SIZE + 4095UL) & -4096UL;
    check_ipl_parmblock((void *) 0, output_addr + SZ__bss_start);
    memset(&_bss, 0, &_ebss - &_bss);
    free_mem_ptr = (unsigned long)&_end;
    free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
    output = (unsigned char *) output_addr;

#ifdef CONFIG_BLK_DEV_INITRD
    /*
     * Move the initrd right behind the end of the decompressed
     * kernel image.
     */
    if (INITRD_START && INITRD_SIZE &&
        INITRD_START < (unsigned long) output + SZ__bss_start) {
        check_ipl_parmblock(output + SZ__bss_start,
                    INITRD_START + INITRD_SIZE);
        memmove(output + SZ__bss_start,
            (void *) INITRD_START, INITRD_SIZE);
        INITRD_START = (unsigned long) output + SZ__bss_start;
    }
#endif

    puts("Uncompressing Linux... ");
    decompress(input_data, input_len, NULL, NULL, output, NULL, error);
    puts("Ok, booting the kernel.\n");
    return (unsigned long) output;
}