LXR linux/arch/alpha/boot/main.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * arch/alpha/boot/main.c
   4 *
   5 * Copyright (C) 1994, 1995 Linus Torvalds
   6 *
   7 * This file is the bootloader for the Linux/AXP kernel
   8 */
   9#include <linux/kernel.h>
  10#include <linux/slab.h>
  11#include <linux/string.h>
  12#include <generated/utsrelease.h>
  13#include <linux/mm.h>
  14
  15#include <asm/console.h>
  16#include <asm/hwrpb.h>
  17
  18#include <stdarg.h>
  19
  20#include "ksize.h"
  21
  22extern unsigned long switch_to_osf_pal(unsigned long nr,
  23        struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
  24        unsigned long *vptb);
  25struct hwrpb_struct *hwrpb = INIT_HWRPB;
  26static struct pcb_struct pcb_va[1];
  27
  28/*
  29 * Find a physical address of a virtual object..
  30 *
  31 * This is easy using the virtual page table address.
  32 */
  33
  34static inline void *
  35find_pa(unsigned long *vptb, void *ptr)
  36{
  37        unsigned long address = (unsigned long) ptr;
  38        unsigned long result;
  39
  40        result = vptb[address >> 13];
  41        result >>= 32;
  42        result <<= 13;
  43        result |= address & 0x1fff;
  44        return (void *) result;
  45}       
  46
  47/*
  48 * This function moves into OSF/1 pal-code, and has a temporary
  49 * PCB for that. The kernel proper should replace this PCB with
  50 * the real one as soon as possible.
  51 *
  52 * The page table muckery in here depends on the fact that the boot
  53 * code has the L1 page table identity-map itself in the second PTE
  54 * in the L1 page table. Thus the L1-page is virtually addressable
  55 * itself (through three levels) at virtual address 0x200802000.
  56 */
  57
  58#define VPTB    ((unsigned long *) 0x200000000)
  59#define L1      ((unsigned long *) 0x200802000)
  60
  61void
  62pal_init(void)
  63{
  64        unsigned long i, rev;
  65        struct percpu_struct * percpu;
  66        struct pcb_struct * pcb_pa;
  67
  68        /* Create the dummy PCB.  */
  69        pcb_va->ksp = 0;
  70        pcb_va->usp = 0;
  71        pcb_va->ptbr = L1[1] >> 32;
  72        pcb_va->asn = 0;
  73        pcb_va->pcc = 0;
  74        pcb_va->unique = 0;
  75        pcb_va->flags = 1;
  76        pcb_va->res1 = 0;
  77        pcb_va->res2 = 0;
  78        pcb_pa = find_pa(VPTB, pcb_va);
  79
  80        /*
  81         * a0 = 2 (OSF)
  82         * a1 = return address, but we give the asm the vaddr of the PCB
  83         * a2 = physical addr of PCB
  84         * a3 = new virtual page table pointer
  85         * a4 = KSP (but the asm sets it)
  86         */
  87        srm_printk("Switching to OSF PAL-code .. ");
  88
  89        i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
  90        if (i) {
  91                srm_printk("failed, code %ld\n", i);
  92                __halt();
  93        }
  94
  95        percpu = (struct percpu_struct *)
  96                (INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
  97        rev = percpu->pal_revision = percpu->palcode_avail[2];
  98
  99        srm_printk("Ok (rev %lx)\n", rev);
 100
 101        tbia(); /* do it directly in case we are SMP */
 102}
 103
 104static inline long openboot(void)
 105{
 106        char bootdev[256];
 107        long result;
 108
 109        result = callback_getenv(ENV_BOOTED_DEV, bootdev, 255);
 110        if (result < 0)
 111                return result;
 112        return callback_open(bootdev, result & 255);
 113}
 114
 115static inline long close(long dev)
 116{
 117        return callback_close(dev);
 118}
 119
 120static inline long load(long dev, unsigned long addr, unsigned long count)
 121{
 122        char bootfile[256];
 123        extern char _end;
 124        long result, boot_size = &_end - (char *) BOOT_ADDR;
 125
 126        result = callback_getenv(ENV_BOOTED_FILE, bootfile, 255);
 127        if (result < 0)
 128                return result;
 129        result &= 255;
 130        bootfile[result] = '\0';
 131        if (result)
 132                srm_printk("Boot file specification (%s) not implemented\n",
 133                       bootfile);
 134        return callback_read(dev, count, (void *)addr, boot_size/512 + 1);
 135}
 136
 137/*
 138 * Start the kernel.
 139 */
 140static void runkernel(void)
 141{
 142        __asm__ __volatile__(
 143                "bis %1,%1,$30\n\t"
 144                "bis %0,%0,$26\n\t"
 145                "ret ($26)"
 146                : /* no outputs: it doesn't even return */
 147                : "r" (START_ADDR),
 148                  "r" (PAGE_SIZE + INIT_STACK));
 149}
 150
 151void start_kernel(void)
 152{
 153        long i;
 154        long dev;
 155        int nbytes;
 156        char envval[256];
 157
 158        srm_printk("Linux/AXP bootloader for Linux " UTS_RELEASE "\n");
 159        if (INIT_HWRPB->pagesize != 8192) {
 160                srm_printk("Expected 8kB pages, got %ldkB\n", INIT_HWRPB->pagesize >> 10);
 161                return;
 162        }
 163        pal_init();
 164        dev = openboot();
 165        if (dev < 0) {
 166                srm_printk("Unable to open boot device: %016lx\n", dev);
 167                return;
 168        }
 169        dev &= 0xffffffff;
 170        srm_printk("Loading vmlinux ...");
 171        i = load(dev, START_ADDR, KERNEL_SIZE);
 172        close(dev);
 173        if (i != KERNEL_SIZE) {
 174                srm_printk("Failed (%lx)\n", i);
 175                return;
 176        }
 177
 178        nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
 179        if (nbytes < 0) {
 180                nbytes = 0;
 181        }
 182        envval[nbytes] = '\0';
 183        strcpy((char*)ZERO_PGE, envval);
 184
 185        srm_printk(" Ok\nNow booting the kernel\n");
 186        runkernel();
 187        for (i = 0 ; i < 0x100000000 ; i++)
 188                /* nothing */;
 189        __halt();
 190}
 191