linux/arch/alpha/boot/bootpz.c
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   1/*
   2 * arch/alpha/boot/bootpz.c
   3 *
   4 * Copyright (C) 1997 Jay Estabrook
   5 *
   6 * This file is used for creating a compressed BOOTP file for the
   7 * Linux/AXP kernel
   8 *
   9 * based significantly on the arch/alpha/boot/main.c of Linus Torvalds
  10 * and the decompression code from MILO.
  11 */
  12#include <linux/kernel.h>
  13#include <linux/slab.h>
  14#include <linux/string.h>
  15#include <generated/utsrelease.h>
  16#include <linux/mm.h>
  17
  18#include <asm/console.h>
  19#include <asm/hwrpb.h>
  20#include <asm/pgtable.h>
  21#include <asm/io.h>
  22
  23#include <stdarg.h>
  24
  25#include "kzsize.h"
  26
  27/* FIXME FIXME FIXME */
  28#define MALLOC_AREA_SIZE 0x200000 /* 2MB for now */
  29/* FIXME FIXME FIXME */
  30
  31
  32/*
  33  WARNING NOTE
  34
  35  It is very possible that turning on additional messages may cause
  36  kernel image corruption due to stack usage to do the printing.
  37
  38*/
  39
  40#undef DEBUG_CHECK_RANGE
  41#undef DEBUG_ADDRESSES
  42#undef DEBUG_LAST_STEPS
  43
  44extern unsigned long switch_to_osf_pal(unsigned long nr,
  45        struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
  46        unsigned long *vptb);
  47
  48extern int decompress_kernel(void* destination, void *source,
  49                             size_t ksize, size_t kzsize);
  50
  51extern void move_stack(unsigned long new_stack);
  52
  53struct hwrpb_struct *hwrpb = INIT_HWRPB;
  54static struct pcb_struct pcb_va[1];
  55
  56/*
  57 * Find a physical address of a virtual object..
  58 *
  59 * This is easy using the virtual page table address.
  60 */
  61#define VPTB    ((unsigned long *) 0x200000000)
  62
  63static inline unsigned long
  64find_pa(unsigned long address)
  65{
  66        unsigned long result;
  67
  68        result = VPTB[address >> 13];
  69        result >>= 32;
  70        result <<= 13;
  71        result |= address & 0x1fff;
  72        return result;
  73}       
  74
  75int
  76check_range(unsigned long vstart, unsigned long vend,
  77            unsigned long kstart, unsigned long kend)
  78{
  79        unsigned long vaddr, kaddr;
  80
  81#ifdef DEBUG_CHECK_RANGE
  82        srm_printk("check_range: V[0x%lx:0x%lx] K[0x%lx:0x%lx]\n",
  83                   vstart, vend, kstart, kend);
  84#endif
  85        /* do some range checking for detecting an overlap... */
  86        for (vaddr = vstart; vaddr <= vend; vaddr += PAGE_SIZE)
  87        {
  88                kaddr = (find_pa(vaddr) | PAGE_OFFSET);
  89                if (kaddr >= kstart && kaddr <= kend)
  90                {
  91#ifdef DEBUG_CHECK_RANGE
  92                        srm_printk("OVERLAP: vaddr 0x%lx kaddr 0x%lx"
  93                                   " [0x%lx:0x%lx]\n",
  94                                   vaddr, kaddr, kstart, kend);
  95#endif
  96                        return 1;
  97                }
  98        }
  99        return 0;
 100}
 101
 102/*
 103 * This function moves into OSF/1 pal-code, and has a temporary
 104 * PCB for that. The kernel proper should replace this PCB with
 105 * the real one as soon as possible.
 106 *
 107 * The page table muckery in here depends on the fact that the boot
 108 * code has the L1 page table identity-map itself in the second PTE
 109 * in the L1 page table. Thus the L1-page is virtually addressable
 110 * itself (through three levels) at virtual address 0x200802000.
 111 */
 112
 113#define L1      ((unsigned long *) 0x200802000)
 114
 115void
 116pal_init(void)
 117{
 118        unsigned long i, rev;
 119        struct percpu_struct * percpu;
 120        struct pcb_struct * pcb_pa;
 121
 122        /* Create the dummy PCB.  */
 123        pcb_va->ksp = 0;
 124        pcb_va->usp = 0;
 125        pcb_va->ptbr = L1[1] >> 32;
 126        pcb_va->asn = 0;
 127        pcb_va->pcc = 0;
 128        pcb_va->unique = 0;
 129        pcb_va->flags = 1;
 130        pcb_va->res1 = 0;
 131        pcb_va->res2 = 0;
 132        pcb_pa = (struct pcb_struct *)find_pa((unsigned long)pcb_va);
 133
 134        /*
 135         * a0 = 2 (OSF)
 136         * a1 = return address, but we give the asm the vaddr of the PCB
 137         * a2 = physical addr of PCB
 138         * a3 = new virtual page table pointer
 139         * a4 = KSP (but the asm sets it)
 140         */
 141        srm_printk("Switching to OSF PAL-code... ");
 142
 143        i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
 144        if (i) {
 145                srm_printk("failed, code %ld\n", i);
 146                __halt();
 147        }
 148
 149        percpu = (struct percpu_struct *)
 150                (INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
 151        rev = percpu->pal_revision = percpu->palcode_avail[2];
 152
 153        srm_printk("OK (rev %lx)\n", rev);
 154
 155        tbia(); /* do it directly in case we are SMP */
 156}
 157
 158/*
 159 * Start the kernel.
 160 */
 161static inline void
 162runkernel(void)
 163{
 164        __asm__ __volatile__(
 165                "bis %0,%0,$27\n\t"
 166                "jmp ($27)"
 167                : /* no outputs: it doesn't even return */
 168                : "r" (START_ADDR));
 169}
 170
 171/* Must record the SP (it is virtual) on entry, so we can make sure
 172   not to overwrite it during movement or decompression. */
 173unsigned long SP_on_entry;
 174
 175/* Calculate the kernel image address based on the end of the BOOTP
 176   bootstrapper (ie this program).
 177*/
 178extern char _end;
 179#define KERNEL_ORIGIN \
 180        ((((unsigned long)&_end) + 511) & ~511)
 181
 182/* Round address to next higher page boundary. */
 183#define NEXT_PAGE(a)    (((a) | (PAGE_SIZE - 1)) + 1)
 184
 185#ifdef INITRD_IMAGE_SIZE
 186# define REAL_INITRD_SIZE INITRD_IMAGE_SIZE
 187#else
 188# define REAL_INITRD_SIZE 0
 189#endif
 190
 191/* Defines from include/asm-alpha/system.h
 192
 193        BOOT_ADDR       Virtual address at which the consoles loads
 194                        the BOOTP image.
 195
 196        KERNEL_START    KSEG address at which the kernel is built to run,
 197                        which includes some initial data pages before the
 198                        code.
 199
 200        START_ADDR      KSEG address of the entry point of kernel code.
 201
 202        ZERO_PGE        KSEG address of page full of zeroes, but 
 203                        upon entry to kerne cvan be expected
 204                        to hold the parameter list and possible
 205                        INTRD information.
 206
 207   These are used in the local defines below.
 208*/
 209  
 210
 211/* Virtual addresses for the BOOTP image. Note that this includes the
 212   bootstrapper code as well as the compressed kernel image, and
 213   possibly the INITRD image.
 214
 215   Oh, and do NOT forget the STACK, which appears to be placed virtually
 216   beyond the end of the loaded image.
 217*/
 218#define V_BOOT_IMAGE_START      BOOT_ADDR
 219#define V_BOOT_IMAGE_END        SP_on_entry
 220
 221/* Virtual addresses for just the bootstrapper part of the BOOTP image. */
 222#define V_BOOTSTRAPPER_START    BOOT_ADDR
 223#define V_BOOTSTRAPPER_END      KERNEL_ORIGIN
 224
 225/* Virtual addresses for just the data part of the BOOTP
 226   image. This may also include the INITRD image, but always
 227   includes the STACK.
 228*/
 229#define V_DATA_START            KERNEL_ORIGIN
 230#define V_INITRD_START          (KERNEL_ORIGIN + KERNEL_Z_SIZE)
 231#define V_INTRD_END             (V_INITRD_START + REAL_INITRD_SIZE)
 232#define V_DATA_END              V_BOOT_IMAGE_END
 233
 234/* KSEG addresses for the uncompressed kernel.
 235
 236   Note that the end address includes workspace for the decompression.
 237   Note also that the DATA_START address is ZERO_PGE, to which we write
 238   just before jumping to the kernel image at START_ADDR.
 239 */
 240#define K_KERNEL_DATA_START     ZERO_PGE
 241#define K_KERNEL_IMAGE_START    START_ADDR
 242#define K_KERNEL_IMAGE_END      (START_ADDR + KERNEL_SIZE)
 243
 244/* Define to where we may have to decompress the kernel image, before
 245   we move it to the final position, in case of overlap. This will be
 246   above the final position of the kernel.
 247
 248   Regardless of overlap, we move the INITRD image to the end of this
 249   copy area, because there needs to be a buffer area after the kernel
 250   for "bootmem" anyway.
 251*/
 252#define K_COPY_IMAGE_START      NEXT_PAGE(K_KERNEL_IMAGE_END)
 253/* Reserve one page below INITRD for the new stack. */
 254#define K_INITRD_START \
 255    NEXT_PAGE(K_COPY_IMAGE_START + KERNEL_SIZE + PAGE_SIZE)
 256#define K_COPY_IMAGE_END \
 257    (K_INITRD_START + REAL_INITRD_SIZE + MALLOC_AREA_SIZE)
 258#define K_COPY_IMAGE_SIZE \
 259    NEXT_PAGE(K_COPY_IMAGE_END - K_COPY_IMAGE_START)
 260
 261void
 262start_kernel(void)
 263{
 264        int must_move = 0;
 265
 266        /* Initialize these for the decompression-in-place situation,
 267           which is the smallest amount of work and most likely to
 268           occur when using the normal START_ADDR of the kernel
 269           (currently set to 16MB, to clear all console code.
 270        */
 271        unsigned long uncompressed_image_start = K_KERNEL_IMAGE_START;
 272        unsigned long uncompressed_image_end = K_KERNEL_IMAGE_END;
 273
 274        unsigned long initrd_image_start = K_INITRD_START;
 275
 276        /*
 277         * Note that this crufty stuff with static and envval
 278         * and envbuf is because:
 279         *
 280         * 1. Frequently, the stack is short, and we don't want to overrun;
 281         * 2. Frequently the stack is where we are going to copy the kernel to;
 282         * 3. A certain SRM console required the GET_ENV output to stack.
 283         *    ??? A comment in the aboot sources indicates that the GET_ENV
 284         *    destination must be quadword aligned.  Might this explain the
 285         *    behaviour, rather than requiring output to the stack, which
 286         *    seems rather far-fetched.
 287         */
 288        static long nbytes;
 289        static char envval[256] __attribute__((aligned(8)));
 290        register unsigned long asm_sp asm("30");
 291
 292        SP_on_entry = asm_sp;
 293
 294        srm_printk("Linux/Alpha BOOTPZ Loader for Linux " UTS_RELEASE "\n");
 295
 296        /* Validity check the HWRPB. */
 297        if (INIT_HWRPB->pagesize != 8192) {
 298                srm_printk("Expected 8kB pages, got %ldkB\n",
 299                           INIT_HWRPB->pagesize >> 10);
 300                return;
 301        }
 302        if (INIT_HWRPB->vptb != (unsigned long) VPTB) {
 303                srm_printk("Expected vptb at %p, got %p\n",
 304                           VPTB, (void *)INIT_HWRPB->vptb);
 305                return;
 306        }
 307
 308        /* PALcode (re)initialization. */
 309        pal_init();
 310
 311        /* Get the parameter list from the console environment variable. */
 312        nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
 313        if (nbytes < 0 || nbytes >= sizeof(envval)) {
 314                nbytes = 0;
 315        }
 316        envval[nbytes] = '\0';
 317
 318#ifdef DEBUG_ADDRESSES
 319        srm_printk("START_ADDR 0x%lx\n", START_ADDR);
 320        srm_printk("KERNEL_ORIGIN 0x%lx\n", KERNEL_ORIGIN);
 321        srm_printk("KERNEL_SIZE 0x%x\n", KERNEL_SIZE);
 322        srm_printk("KERNEL_Z_SIZE 0x%x\n", KERNEL_Z_SIZE);
 323#endif
 324
 325        /* Since all the SRM consoles load the BOOTP image at virtual
 326         * 0x20000000, we have to ensure that the physical memory
 327         * pages occupied by that image do NOT overlap the physical
 328         * address range where the kernel wants to be run.  This
 329         * causes real problems when attempting to cdecompress the
 330         * former into the latter... :-(
 331         *
 332         * So, we may have to decompress/move the kernel/INITRD image
 333         * virtual-to-physical someplace else first before moving
 334         * kernel /INITRD to their final resting places... ;-}
 335         *
 336         * Sigh...
 337         */
 338
 339        /* First, check to see if the range of addresses occupied by
 340           the bootstrapper part of the BOOTP image include any of the
 341           physical pages into which the kernel will be placed for
 342           execution.
 343
 344           We only need check on the final kernel image range, since we
 345           will put the INITRD someplace that we can be sure is not
 346           in conflict.
 347         */
 348        if (check_range(V_BOOTSTRAPPER_START, V_BOOTSTRAPPER_END,
 349                        K_KERNEL_DATA_START, K_KERNEL_IMAGE_END))
 350        {
 351                srm_printk("FATAL ERROR: overlap of bootstrapper code\n");
 352                __halt();
 353        }
 354
 355        /* Next, check to see if the range of addresses occupied by
 356           the compressed kernel/INITRD/stack portion of the BOOTP
 357           image include any of the physical pages into which the
 358           decompressed kernel or the INITRD will be placed for
 359           execution.
 360         */
 361        if (check_range(V_DATA_START, V_DATA_END,
 362                        K_KERNEL_IMAGE_START, K_COPY_IMAGE_END))
 363        {
 364#ifdef DEBUG_ADDRESSES
 365                srm_printk("OVERLAP: cannot decompress in place\n");
 366#endif
 367                uncompressed_image_start = K_COPY_IMAGE_START;
 368                uncompressed_image_end = K_COPY_IMAGE_END;
 369                must_move = 1;
 370
 371                /* Finally, check to see if the range of addresses
 372                   occupied by the compressed kernel/INITRD part of
 373                   the BOOTP image include any of the physical pages
 374                   into which that part is to be copied for
 375                   decompression.
 376                */
 377                while (check_range(V_DATA_START, V_DATA_END,
 378                                   uncompressed_image_start,
 379                                   uncompressed_image_end))
 380                {
 381#if 0
 382                        uncompressed_image_start += K_COPY_IMAGE_SIZE;
 383                        uncompressed_image_end += K_COPY_IMAGE_SIZE;
 384                        initrd_image_start += K_COPY_IMAGE_SIZE;
 385#else
 386                        /* Keep as close as possible to end of BOOTP image. */
 387                        uncompressed_image_start += PAGE_SIZE;
 388                        uncompressed_image_end += PAGE_SIZE;
 389                        initrd_image_start += PAGE_SIZE;
 390#endif
 391                }
 392        }
 393
 394        srm_printk("Starting to load the kernel with args '%s'\n", envval);
 395
 396#ifdef DEBUG_ADDRESSES
 397        srm_printk("Decompressing the kernel...\n"
 398                   "...from 0x%lx to 0x%lx size 0x%x\n",
 399                   V_DATA_START,
 400                   uncompressed_image_start,
 401                   KERNEL_SIZE);
 402#endif
 403        decompress_kernel((void *)uncompressed_image_start,
 404                          (void *)V_DATA_START,
 405                          KERNEL_SIZE, KERNEL_Z_SIZE);
 406
 407        /*
 408         * Now, move things to their final positions, if/as required.
 409         */
 410
 411#ifdef INITRD_IMAGE_SIZE
 412
 413        /* First, we always move the INITRD image, if present. */
 414#ifdef DEBUG_ADDRESSES
 415        srm_printk("Moving the INITRD image...\n"
 416                   " from 0x%lx to 0x%lx size 0x%x\n",
 417                   V_INITRD_START,
 418                   initrd_image_start,
 419                   INITRD_IMAGE_SIZE);
 420#endif
 421        memcpy((void *)initrd_image_start, (void *)V_INITRD_START,
 422               INITRD_IMAGE_SIZE);
 423
 424#endif /* INITRD_IMAGE_SIZE */
 425
 426        /* Next, we may have to move the uncompressed kernel to the
 427           final destination.
 428         */
 429        if (must_move) {
 430#ifdef DEBUG_ADDRESSES
 431                srm_printk("Moving the uncompressed kernel...\n"
 432                           "...from 0x%lx to 0x%lx size 0x%x\n",
 433                           uncompressed_image_start,
 434                           K_KERNEL_IMAGE_START,
 435                           (unsigned)KERNEL_SIZE);
 436#endif
 437                /*
 438                 * Move the stack to a safe place to ensure it won't be
 439                 * overwritten by kernel image.
 440                 */
 441                move_stack(initrd_image_start - PAGE_SIZE);
 442
 443                memcpy((void *)K_KERNEL_IMAGE_START,
 444                       (void *)uncompressed_image_start, KERNEL_SIZE);
 445        }
 446        
 447        /* Clear the zero page, then move the argument list in. */
 448#ifdef DEBUG_LAST_STEPS
 449        srm_printk("Preparing ZERO_PGE...\n");
 450#endif
 451        memset((char*)ZERO_PGE, 0, PAGE_SIZE);
 452        strcpy((char*)ZERO_PGE, envval);
 453
 454#ifdef INITRD_IMAGE_SIZE
 455
 456#ifdef DEBUG_LAST_STEPS
 457        srm_printk("Preparing INITRD info...\n");
 458#endif
 459        /* Finally, set the INITRD paramenters for the kernel. */
 460        ((long *)(ZERO_PGE+256))[0] = initrd_image_start;
 461        ((long *)(ZERO_PGE+256))[1] = INITRD_IMAGE_SIZE;
 462
 463#endif /* INITRD_IMAGE_SIZE */
 464
 465#ifdef DEBUG_LAST_STEPS
 466        srm_printk("Doing 'runkernel()'...\n");
 467#endif
 468        runkernel();
 469}
 470
 471 /* dummy function, should never be called. */
 472void *__kmalloc(size_t size, gfp_t flags)
 473{
 474        return (void *)NULL;
 475}
 476