arch/alpha/boot/bootpz.c

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