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#include <asm/pgtable.h>
  18
  19#include <stdarg.h>
  20
  21#include "ksize.h"
  22
  23extern unsigned long switch_to_osf_pal(unsigned long nr,
  24        struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
  25        unsigned long *vptb);
  26struct hwrpb_struct *hwrpb = INIT_HWRPB;
  27static struct pcb_struct pcb_va[1];
  28
  29/*
  30 * Find a physical address of a virtual object..
  31 *
  32 * This is easy using the virtual page table address.
  33 */
  34
  35static inline void *
  36find_pa(unsigned long *vptb, void *ptr)
  37{
  38        unsigned long address = (unsigned long) ptr;
  39        unsigned long result;
  40
  41        result = vptb[address >> 13];
  42        result >>= 32;
  43        result <<= 13;
  44        result |= address & 0x1fff;
  45        return (void *) result;
  46}       
  47
  48/*
  49 * This function moves into OSF/1 pal-code, and has a temporary
  50 * PCB for that. The kernel proper should replace this PCB with
  51 * the real one as soon as possible.
  52 *
  53 * The page table muckery in here depends on the fact that the boot
  54 * code has the L1 page table identity-map itself in the second PTE
  55 * in the L1 page table. Thus the L1-page is virtually addressable
  56 * itself (through three levels) at virtual address 0x200802000.
  57 */
  58
  59#define VPTB    ((unsigned long *) 0x200000000)
  60#define L1      ((unsigned long *) 0x200802000)
  61
  62void
  63pal_init(void)
  64{
  65        unsigned long i, rev;
  66        struct percpu_struct * percpu;
  67        struct pcb_struct * pcb_pa;
  68
  69        /* Create the dummy PCB.  */
  70        pcb_va->ksp = 0;
  71        pcb_va->usp = 0;
  72        pcb_va->ptbr = L1[1] >> 32;
  73        pcb_va->asn = 0;
  74        pcb_va->pcc = 0;
  75        pcb_va->unique = 0;
  76        pcb_va->flags = 1;
  77        pcb_va->res1 = 0;
  78        pcb_va->res2 = 0;
  79        pcb_pa = find_pa(VPTB, pcb_va);
  80
  81        /*
  82         * a0 = 2 (OSF)
  83         * a1 = return address, but we give the asm the vaddr of the PCB
  84         * a2 = physical addr of PCB
  85         * a3 = new virtual page table pointer
  86         * a4 = KSP (but the asm sets it)
  87         */
  88        srm_printk("Switching to OSF PAL-code .. ");
  89
  90        i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
  91        if (i) {
  92                srm_printk("failed, code %ld\n", i);
  93                __halt();
  94        }
  95
  96        percpu = (struct percpu_struct *)
  97                (INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
  98        rev = percpu->pal_revision = percpu->palcode_avail[2];
  99
 100        srm_printk("Ok (rev %lx)\n", rev);
 101
 102        tbia(); /* do it directly in case we are SMP */
 103}
 104
 105static inline long openboot(void)
 106{
 107        char bootdev[256];
 108        long result;
 109
 110        result = callback_getenv(ENV_BOOTED_DEV, bootdev, 255);
 111        if (result < 0)
 112                return result;
 113        return callback_open(bootdev, result & 255);
 114}
 115
 116static inline long close(long dev)
 117{
 118        return callback_close(dev);
 119}
 120
 121static inline long load(long dev, unsigned long addr, unsigned long count)
 122{
 123        char bootfile[256];
 124        extern char _end;
 125        long result, boot_size = &_end - (char *) BOOT_ADDR;
 126
 127        result = callback_getenv(ENV_BOOTED_FILE, bootfile, 255);
 128        if (result < 0)
 129                return result;
 130        result &= 255;
 131        bootfile[result] = '\0';
 132        if (result)
 133                srm_printk("Boot file specification (%s) not implemented\n",
 134                       bootfile);
 135        return callback_read(dev, count, (void *)addr, boot_size/512 + 1);
 136}
 137
 138/*
 139 * Start the kernel.
 140 */
 141static void runkernel(void)
 142{
 143        __asm__ __volatile__(
 144                "bis %1,%1,$30\n\t"
 145                "bis %0,%0,$26\n\t"
 146                "ret ($26)"
 147                : /* no outputs: it doesn't even return */
 148                : "r" (START_ADDR),
 149                  "r" (PAGE_SIZE + INIT_STACK));
 150}
 151
 152void start_kernel(void)
 153{
 154        long i;
 155        long dev;
 156        int nbytes;
 157        char envval[256];
 158
 159        srm_printk("Linux/AXP bootloader for Linux " UTS_RELEASE "\n");
 160        if (INIT_HWRPB->pagesize != 8192) {
 161                srm_printk("Expected 8kB pages, got %ldkB\n", INIT_HWRPB->pagesize >> 10);
 162                return;
 163        }
 164        pal_init();
 165        dev = openboot();
 166        if (dev < 0) {
 167                srm_printk("Unable to open boot device: %016lx\n", dev);
 168                return;
 169        }
 170        dev &= 0xffffffff;
 171        srm_printk("Loading vmlinux ...");
 172        i = load(dev, START_ADDR, KERNEL_SIZE);
 173        close(dev);
 174        if (i != KERNEL_SIZE) {
 175                srm_printk("Failed (%lx)\n", i);
 176                return;
 177        }
 178
 179        nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
 180        if (nbytes < 0) {
 181                nbytes = 0;
 182        }
 183        envval[nbytes] = '\0';
 184        strcpy((char*)ZERO_PGE, envval);
 185
 186        srm_printk(" Ok\nNow booting the kernel\n");
 187        runkernel();
 188        for (i = 0 ; i < 0x100000000 ; i++)
 189                /* nothing */;
 190        __halt();
 191}
 192