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
  22 extern unsigned long switch_to_osf_pal(unsigned long nr,
  23         struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
  24         unsigned long *vptb);
  25 struct hwrpb_struct *hwrpb = INIT_HWRPB;
  26 static 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
  34 static inline void *
  35 find_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
  61 void
  62 pal_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
 104 static 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
 115 static inline long close(long dev)
 116 {
 117         return callback_close(dev);
 118 }
 119
 120 static 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  */
 140 static 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
 151 void 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 }