Il CD di internet/CD.iso/SOURCE/KERNEL-S/V1.2/LINUX-1.2/LINUX-1/linux/arch/alpha/boot/main.c

C/C++ Source or Header | 1995-01-29 | 4.8 KB | 208 lines

/*
 * arch/alpha/boot/main.c
 *
 * Copyright (C) 1994, 1995 Linus Torvalds
 *
 * This file is the bootloader for the Linux/AXP kernel
 */
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/version.h>
#include <linux/mm.h>

#include <asm/system.h>
#include <asm/console.h>
#include <asm/hwrpb.h>

#include <stdarg.h>

extern int vsprintf(char *, const char *, va_list);
extern unsigned long switch_to_osf_pal(unsigned long nr,
    struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
    unsigned long vptb, unsigned long *kstk);

int printk(const char * fmt, ...)
{
    va_list args;
    int i;
    static char buf[1024];

    va_start(args, fmt);
    i = vsprintf(buf, fmt, args);
    va_end(args);
    puts(buf,i);
    return i;
}

#define hwrpb (*INIT_HWRPB)

/*
 * Find a physical address of a virtual object..
 *
 * This is easy using the virtual page table address.
 */
struct pcb_struct * find_pa(unsigned long *vptb, struct pcb_struct * pcb)
{
    unsigned long address = (unsigned long) pcb;
    unsigned long result;

    result = vptb[address >> 13];
    result >>= 32;
    result <<= 13;
    result |= address & 0x1fff;
    return (struct pcb_struct *) result;
}

/*
 * This function moves into OSF/1 pal-code, and has a temporary
 * PCB for that. The kernel proper should replace this PCB with
 * the real one as soon as possible.
 *
 * The page table muckery in here depends on the fact that the boot
 * code has the L1 page table identity-map itself in the second PTE
 * in the L1 page table. Thus the L1-page is virtually addressable
 * itself (through three levels) at virtual address 0x200802000.
 *
 * As we don't want it there anyway, we also move the L1 self-map
 * up as high as we can, so that the last entry in the L1 page table
 * maps the page tables.
 *
 * As a result, the OSF/1 pal-code will instead use a virtual page table
 * map located at 0xffffffe00000000.
 */
#define pcb_va ((struct pcb_struct *) 0x20000000)
#define old_vptb (0x0000000200000000UL)
#define new_vptb (0xfffffffe00000000UL)
void pal_init(void)
{
    unsigned long i, rev, sum;
    unsigned long *L1, *l;
    struct percpu_struct * percpu;
    struct pcb_struct * pcb_pa;

    /* Find the level 1 page table and duplicate it in high memory */
    L1 = (unsigned long *) 0x200802000UL; /* (1<<33 | 1<<23 | 1<<13) */
    L1[1023] = L1[1];

    percpu = (struct percpu_struct *) (hwrpb.processor_offset + (unsigned long) &hwrpb),

    pcb_va->ksp = 0;
    pcb_va->usp = 0;
    pcb_va->ptbr = L1[1] >> 32;
    pcb_va->asn = 0;
    pcb_va->pcc = 0;
    pcb_va->unique = 0;
    pcb_va->flags = 1;
    pcb_pa = find_pa((unsigned long *) old_vptb, pcb_va);
    printk("Switching to OSF PAL-code .. ");
    /*
     * a0 = 2 (OSF)
     * a1 = return address, but we give the asm the virtual addr of the PCB
     * a2 = physical addr of PCB
     * a3 = new virtual page table pointer
     * a4 = KSP (but we give it 0, asm sets it)
     */
    i = switch_to_osf_pal(
        2,
        pcb_va,
        pcb_pa,
        new_vptb,
        0);
    if (i) {
        printk("failed, code %ld\n", i);
        halt();
    }
    rev = percpu->pal_revision = percpu->palcode_avail[2];

    hwrpb.vptb = new_vptb;

    /* update checksum: */
    sum = 0;
    for (l = (unsigned long *) &hwrpb; l < (unsigned long *) &hwrpb.chksum; ++l)
        sum += *l;
    hwrpb.chksum = sum;

    printk("Ok (rev %lx)\n", rev);
    /* remove the old virtual page-table mapping */
    L1[1] = 0;
    invalidate_all();
}

extern int _end;

static inline long openboot(void)
{
    char bootdev[256];
    long result;

    result = dispatch(CCB_GET_ENV, ENV_BOOTED_DEV, bootdev, 255);
    if (result < 0)
        return result;
    return dispatch(CCB_OPEN, bootdev, result & 255);
}

static inline long close(long dev)
{
    return dispatch(CCB_CLOSE, dev);
}

static inline long load(long dev, unsigned long addr, unsigned long count)
{
    char bootfile[256];
    long result;

    result = dispatch(CCB_GET_ENV, ENV_BOOTED_FILE, bootfile, 255);
    if (result < 0)
        return result;
    result &= 255;
    bootfile[result] = '\0';
    if (result)
        printk("Boot file specification (%s) not implemented\n", bootfile);
    return dispatch(CCB_READ, dev, count, addr, BOOT_SIZE/512 + 1);
}

/*
 * Start the kernel.
 */
static void runkernel(void)
{
    __asm__ __volatile__(
        "bis %1,%1,$30\n\t"
        "bis %0,%0,$26\n\t"
        "ret ($26)"
        : /* no outputs: it doesn't even return */
        : "r" (START_ADDR),
          "r" (PAGE_SIZE + INIT_STACK));
}

void start_kernel(void)
{
    long i;
    long dev;

    printk("Linux/AXP bootloader for Linux " UTS_RELEASE "\n");
    if (hwrpb.pagesize != 8192) {
        printk("Expected 8kB pages, got %ldkB\n", hwrpb.pagesize >> 10);
        return;
    }
    pal_init();
    dev = openboot();
    if (dev < 0) {
        printk("Unable to open boot device: %016lx\n", dev);
        return;
    }
    dev &= 0xffffffff;
    printk("Loading vmlinux ...");
    i = load(dev, START_ADDR, START_SIZE);
    close(dev);
    if (i != START_SIZE) {
        printk("Failed (%lx)\n", i);
        return;
    }
    printk(" Ok\nNow booting the kernel\n");
    runkernel();
    for (i = 0 ; i < 0x100000000 ; i++)
        /* nothing */;
    halt();
}