arch/alpha/boot/bootp.c

   1 /*
   2  * arch/alpha/boot/bootp.c
   3  *
   4  * Copyright (C) 1997 Jay Estabrook
   5  *
   6  * This file is used for creating a bootp file for the Linux/AXP kernel
   7  *
   8  * based significantly on the arch/alpha/boot/main.c of Linus Torvalds
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/string.h>
  12 #include <linux/version.h>
  13 #include <linux/mm.h>
  14
  15 #include <asm/system.h>
  16 #include <asm/console.h>
  17 #include <asm/hwrpb.h>
  18 #include <asm/pgtable.h>
  19 #include <asm/io.h>
  20
  21 #include <stdarg.h>
  22
  23 #include "ksize.h"
  24
  25 extern unsigned long switch_to_osf_pal(unsigned long nr,
  26         struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
  27         unsigned long *vptb);
  28
  29 struct hwrpb_struct *hwrpb = INIT_HWRPB;
  30 static struct pcb_struct pcb_va[1];
  31
  32 /*
  33  * Find a physical address of a virtual object..
  34  *
  35  * This is easy using the virtual page table address.
  36  */
  37
  38 static inline void *
  39 find_pa(unsigned long *vptb, void *ptr)
  40 {
  41         unsigned long address = (unsigned long) ptr;
  42         unsigned long result;
  43
  44         result = vptb[address >> 13];
  45         result >>= 32;
  46         result <<= 13;
  47         result |= address & 0x1fff;
  48         return (void *) result;
  49 }
  50
  51 /*
  52  * This function moves into OSF/1 pal-code, and has a temporary
  53  * PCB for that. The kernel proper should replace this PCB with
  54  * the real one as soon as possible.
  55  *
  56  * The page table muckery in here depends on the fact that the boot
  57  * code has the L1 page table identity-map itself in the second PTE
  58  * in the L1 page table. Thus the L1-page is virtually addressable
  59  * itself (through three levels) at virtual address 0x200802000.
  60  */
  61
  62 #define VPTB    ((unsigned long *) 0x200000000)
  63 #define L1      ((unsigned long *) 0x200802000)
  64
  65 void
  66 pal_init(void)
  67 {
  68         unsigned long i, rev;
  69         struct percpu_struct * percpu;
  70         struct pcb_struct * pcb_pa;
  71
  72         /* Create the dummy PCB.  */
  73         pcb_va->ksp = 0;
  74         pcb_va->usp = 0;
  75         pcb_va->ptbr = L1[1] >> 32;
  76         pcb_va->asn = 0;
  77         pcb_va->pcc = 0;
  78         pcb_va->unique = 0;
  79         pcb_va->flags = 1;
  80         pcb_va->res1 = 0;
  81         pcb_va->res2 = 0;
  82         pcb_pa = find_pa(VPTB, pcb_va);
  83
  84         /*
  85          * a0 = 2 (OSF)
  86          * a1 = return address, but we give the asm the vaddr of the PCB
  87          * a2 = physical addr of PCB
  88          * a3 = new virtual page table pointer
  89          * a4 = KSP (but the asm sets it)
  90          */
  91         srm_printk("Switching to OSF PAL-code .. ");
  92
  93         i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
  94         if (i) {
  95                 srm_printk("failed, code %ld\n", i);
  96                 halt();
  97         }
  98
  99         percpu = (struct percpu_struct *)
 100                 (INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
 101         rev = percpu->pal_revision = percpu->palcode_avail[2];
 102
 103         srm_printk("Ok (rev %lx)\n", rev);
 104
 105         tbia(); /* do it directly in case we are SMP */
 106 }
 107
 108 static inline void
 109 load(unsigned long dst, unsigned long src, unsigned long count)
 110 {
 111         memcpy((void *)dst, (void *)src, count);
 112 }
 113
 114 /*
 115  * Start the kernel.
 116  */
 117 static inline void
 118 runkernel(void)
 119 {
 120         __asm__ __volatile__(
 121                 "bis %1,%1,$30\n\t"
 122                 "bis %0,%0,$27\n\t"
 123                 "jmp ($27)"
 124                 : /* no outputs: it doesn't even return */
 125                 : "r" (START_ADDR),
 126                   "r" (PAGE_SIZE + INIT_STACK));
 127 }
 128
 129 extern char _end;
 130 #define KERNEL_ORIGIN \
 131         ((((unsigned long)&_end) + 511) & ~511)
 132
 133 void
 134 start_kernel(void)
 135 {
 136         /*
 137          * Note that this crufty stuff with static and envval
 138          * and envbuf is because:
 139          *
 140          * 1. Frequently, the stack is short, and we don't want to overrun;
 141          * 2. Frequently the stack is where we are going to copy the kernel to;
 142          * 3. A certain SRM console required the GET_ENV output to stack.
 143          *    ??? A comment in the aboot sources indicates that the GET_ENV
 144          *    destination must be quadword aligned.  Might this explain the
 145          *    behaviour, rather than requiring output to the stack, which
 146          *    seems rather far-fetched.
 147          */
 148         static long nbytes;
 149         static char envval[256] __attribute__((aligned(8)));
 150 #ifdef INITRD_SIZE
 151         static unsigned long initrd_start;
 152 #endif
 153
 154         srm_printk("Linux/AXP bootp loader for Linux " UTS_RELEASE "\n");
 155         if (INIT_HWRPB->pagesize != 8192) {
 156                 srm_printk("Expected 8kB pages, got %ldkB\n",
 157                            INIT_HWRPB->pagesize >> 10);
 158                 return;
 159         }
 160         if (INIT_HWRPB->vptb != (unsigned long) VPTB) {
 161                 srm_printk("Expected vptb at %p, got %p\n",
 162                            VPTB, (void *)INIT_HWRPB->vptb);
 163                 return;
 164         }
 165         pal_init();
 166
 167 #ifdef INITRD_SIZE
 168         /* The initrd must be page-aligned.  See below for the
 169            cause of the magic number 5.  */
 170         initrd_start = ((START_ADDR + 5*KERNEL_SIZE) | (PAGE_SIZE-1)) + 1;
 171         srm_printk("Initrd positioned at %#lx\n", initrd_start);
 172 #endif
 173
 174         nbytes = srm_dispatch(CCB_GET_ENV, ENV_BOOTED_OSFLAGS,
 175                               envval, sizeof(envval));
 176         if (nbytes < 0 || nbytes >= sizeof(envval)) {
 177                 nbytes = 0;
 178         }
 179         envval[nbytes] = '\0';
 180         srm_printk("Loading the kernel...'%s'\n", envval);
 181
 182         /* NOTE: *no* callbacks or printouts from here on out!!! */
 183
 184         /*
 185          * This is a hack, as some consoles seem to get virtual 20000000
 186          * (ie where the SRM console puts the kernel bootp image) memory
 187          * overlapping physical 310000 memory, which causes real problems
 188          * when attempting to copy the former to the latter... :-(
 189          *
 190          * So, we first move the kernel virtual-to-physical way above where
 191          * we physically want the kernel to end up, then copy it from there
 192          * to its final resting place... ;-}
 193          *
 194          * Sigh...
 195          */
 196
 197 #ifdef INITRD_SIZE
 198         load(initrd_start, KERNEL_ORIGIN+KERNEL_SIZE, INITRD_SIZE);
 199 #endif
 200         load(START_ADDR+(4*KERNEL_SIZE), KERNEL_ORIGIN, KERNEL_SIZE);
 201         load(START_ADDR, START_ADDR+(4*KERNEL_SIZE), KERNEL_SIZE);
 202
 203         memset((char*)ZERO_PAGE(0), 0, PAGE_SIZE);
 204         strcpy((char*)ZERO_PAGE(0), envval);
 205 #ifdef INITRD_SIZE
 206         ((long *)(ZERO_PAGE(0)+256))[0] = initrd_start;
 207         ((long *)(ZERO_PAGE(0)+256))[1] = INITRD_SIZE;
 208 #endif
 209
 210         runkernel();
 211 }