arch/alpha/boot/main.c

   1 /*
   2  * arch/alpha/boot/main.c
   3  *
   4  * Copyright (C) 1994, 1995 Linus Torvalds
   5  *
   6  * This file is the bootloader for the Linux/AXP kernel
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/slab.h>
  10 #include <linux/string.h>
  11 #include <generated/utsrelease.h>
  12 #include <linux/mm.h>
  13
  14 #include <asm/system.h>
  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
  23 extern int vsprintf(char *, const char *, va_list);
  24 extern unsigned long switch_to_osf_pal(unsigned long nr,
  25         struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
  26         unsigned long *vptb);
  27 struct hwrpb_struct *hwrpb = INIT_HWRPB;
  28 static struct pcb_struct pcb_va[1];
  29
  30 /*
  31  * Find a physical address of a virtual object..
  32  *
  33  * This is easy using the virtual page table address.
  34  */
  35
  36 static inline void *
  37 find_pa(unsigned long *vptb, void *ptr)
  38 {
  39         unsigned long address = (unsigned long) ptr;
  40         unsigned long result;
  41
  42         result = vptb[address >> 13];
  43         result >>= 32;
  44         result <<= 13;
  45         result |= address & 0x1fff;
  46         return (void *) result;
  47 }
  48
  49 /*
  50  * This function moves into OSF/1 pal-code, and has a temporary
  51  * PCB for that. The kernel proper should replace this PCB with
  52  * the real one as soon as possible.
  53  *
  54  * The page table muckery in here depends on the fact that the boot
  55  * code has the L1 page table identity-map itself in the second PTE
  56  * in the L1 page table. Thus the L1-page is virtually addressable
  57  * itself (through three levels) at virtual address 0x200802000.
  58  */
  59
  60 #define VPTB    ((unsigned long *) 0x200000000)
  61 #define L1      ((unsigned long *) 0x200802000)
  62
  63 void
  64 pal_init(void)
  65 {
  66         unsigned long i, rev;
  67         struct percpu_struct * percpu;
  68         struct pcb_struct * pcb_pa;
  69
  70         /* Create the dummy PCB.  */
  71         pcb_va->ksp = 0;
  72         pcb_va->usp = 0;
  73         pcb_va->ptbr = L1[1] >> 32;
  74         pcb_va->asn = 0;
  75         pcb_va->pcc = 0;
  76         pcb_va->unique = 0;
  77         pcb_va->flags = 1;
  78         pcb_va->res1 = 0;
  79         pcb_va->res2 = 0;
  80         pcb_pa = find_pa(VPTB, pcb_va);
  81
  82         /*
  83          * a0 = 2 (OSF)
  84          * a1 = return address, but we give the asm the vaddr of the PCB
  85          * a2 = physical addr of PCB
  86          * a3 = new virtual page table pointer
  87          * a4 = KSP (but the asm sets it)
  88          */
  89         srm_printk("Switching to OSF PAL-code .. ");
  90
  91         i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
  92         if (i) {
  93                 srm_printk("failed, code %ld\n", i);
  94                 __halt();
  95         }
  96
  97         percpu = (struct percpu_struct *)
  98                 (INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
  99         rev = percpu->pal_revision = percpu->palcode_avail[2];
 100
 101         srm_printk("Ok (rev %lx)\n", rev);
 102
 103         tbia(); /* do it directly in case we are SMP */
 104 }
 105
 106 static inline long openboot(void)
 107 {
 108         char bootdev[256];
 109         long result;
 110
 111         result = callback_getenv(ENV_BOOTED_DEV, bootdev, 255);
 112         if (result < 0)
 113                 return result;
 114         return callback_open(bootdev, result & 255);
 115 }
 116
 117 static inline long close(long dev)
 118 {
 119         return callback_close(dev);
 120 }
 121
 122 static inline long load(long dev, unsigned long addr, unsigned long count)
 123 {
 124         char bootfile[256];
 125         extern char _end;
 126         long result, boot_size = &_end - (char *) BOOT_ADDR;
 127
 128         result = callback_getenv(ENV_BOOTED_FILE, bootfile, 255);
 129         if (result < 0)
 130                 return result;
 131         result &= 255;
 132         bootfile[result] = '\0';
 133         if (result)
 134                 srm_printk("Boot file specification (%s) not implemented\n",
 135                        bootfile);
 136         return callback_read(dev, count, (void *)addr, boot_size/512 + 1);
 137 }
 138
 139 /*
 140  * Start the kernel.
 141  */
 142 static void runkernel(void)
 143 {
 144         __asm__ __volatile__(
 145                 "bis %1,%1,$30\n\t"
 146                 "bis %0,%0,$26\n\t"
 147                 "ret ($26)"
 148                 : /* no outputs: it doesn't even return */
 149                 : "r" (START_ADDR),
 150                   "r" (PAGE_SIZE + INIT_STACK));
 151 }
 152
 153 void start_kernel(void)
 154 {
 155         long i;
 156         long dev;
 157         int nbytes;
 158         char envval[256];
 159
 160         srm_printk("Linux/AXP bootloader for Linux " UTS_RELEASE "\n");
 161         if (INIT_HWRPB->pagesize != 8192) {
 162                 srm_printk("Expected 8kB pages, got %ldkB\n", INIT_HWRPB->pagesize >> 10);
 163                 return;
 164         }
 165         pal_init();
 166         dev = openboot();
 167         if (dev < 0) {
 168                 srm_printk("Unable to open boot device: %016lx\n", dev);
 169                 return;
 170         }
 171         dev &= 0xffffffff;
 172         srm_printk("Loading vmlinux ...");
 173         i = load(dev, START_ADDR, KERNEL_SIZE);
 174         close(dev);
 175         if (i != KERNEL_SIZE) {
 176                 srm_printk("Failed (%lx)\n", i);
 177                 return;
 178         }
 179
 180         nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
 181         if (nbytes < 0) {
 182                 nbytes = 0;
 183         }
 184         envval[nbytes] = '\0';
 185         strcpy((char*)ZERO_PGE, envval);
 186
 187         srm_printk(" Ok\nNow booting the kernel\n");
 188         runkernel();
 189         for (i = 0 ; i < 0x100000000 ; i++)
 190                 /* nothing */;
 191         __halt();
 192 }