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/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
  44 extern 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
  48 extern int decompress_kernel(void* destination, void *source,
  49                              size_t ksize, size_t kzsize);
  50
  51 extern void move_stack(unsigned long new_stack);
  52
  53 struct hwrpb_struct *hwrpb = INIT_HWRPB;
  54 static 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
  63 static inline unsigned long
  64 find_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
  75 int
  76 check_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
 115 void
 116 pal_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  */
 161 static inline void
 162 runkernel(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. */
 173 unsigned long SP_on_entry;
 174
 175 /* Calculate the kernel image address based on the end of the BOOTP
 176    bootstrapper (ie this program).
 177 */
 178 extern 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
 261 void
 262 start_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. */
 472 void *__kmalloc(size_t size, gfp_t flags)
 473 {
 474         return (void *)NULL;
 475 }