arch/sparc64/kernel/setup.c

   1 /*  $Id: setup.c,v 1.72 2002/02/09 19:49:30 davem Exp $
   2  *  linux/arch/sparc64/kernel/setup.c
   3  *
   4  *  Copyright (C) 1995,1996  David S. Miller (davem@caip.rutgers.edu)
   5  *  Copyright (C) 1997       Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   6  */
   7
   8 #include <linux/errno.h>
   9 #include <linux/sched.h>
  10 #include <linux/kernel.h>
  11 #include <linux/mm.h>
  12 #include <linux/stddef.h>
  13 #include <linux/unistd.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/slab.h>
  16 #include <asm/smp.h>
  17 #include <linux/user.h>
  18 #include <linux/a.out.h>
  19 #include <linux/tty.h>
  20 #include <linux/delay.h>
  21 #include <linux/config.h>
  22 #include <linux/fs.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/syscalls.h>
  25 #include <linux/kdev_t.h>
  26 #include <linux/major.h>
  27 #include <linux/string.h>
  28 #include <linux/init.h>
  29 #include <linux/inet.h>
  30 #include <linux/console.h>
  31 #include <linux/root_dev.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/cpu.h>
  34 #include <linux/initrd.h>
  35
  36 #include <asm/segment.h>
  37 #include <asm/system.h>
  38 #include <asm/io.h>
  39 #include <asm/processor.h>
  40 #include <asm/oplib.h>
  41 #include <asm/page.h>
  42 #include <asm/pgtable.h>
  43 #include <asm/idprom.h>
  44 #include <asm/head.h>
  45 #include <asm/starfire.h>
  46 #include <asm/hardirq.h>
  47 #include <asm/mmu_context.h>
  48 #include <asm/timer.h>
  49 #include <asm/sections.h>
  50 #include <asm/setup.h>
  51
  52 #ifdef CONFIG_IP_PNP
  53 #include <net/ipconfig.h>
  54 #endif
  55
  56 struct screen_info screen_info = {
  57         0, 0,                   /* orig-x, orig-y */
  58         0,                      /* unused */
  59         0,                      /* orig-video-page */
  60         0,                      /* orig-video-mode */
  61         128,                    /* orig-video-cols */
  62         0, 0, 0,                /* unused, ega_bx, unused */
  63         54,                     /* orig-video-lines */
  64         0,                      /* orig-video-isVGA */
  65         16                      /* orig-video-points */
  66 };
  67
  68 /* Typing sync at the prom prompt calls the function pointed to by
  69  * the sync callback which I set to the following function.
  70  * This should sync all filesystems and return, for now it just
  71  * prints out pretty messages and returns.
  72  */
  73
  74 void (*prom_palette)(int);
  75 void (*prom_keyboard)(void);
  76
  77 static void
  78 prom_console_write(struct console *con, const char *s, unsigned n)
  79 {
  80         prom_write(s, n);
  81 }
  82
  83 static struct console prom_console = {
  84         .name =         "prom",
  85         .write =        prom_console_write,
  86         .flags =        CON_CONSDEV | CON_ENABLED,
  87         .index =        -1,
  88 };
  89
  90 #define PROM_TRUE       -1
  91 #define PROM_FALSE      0
  92
  93 /* Pretty sick eh? */
  94 int prom_callback(long *args)
  95 {
  96         struct console *cons, *saved_console = NULL;
  97         unsigned long flags;
  98         char *cmd;
  99         extern spinlock_t prom_entry_lock;
 100
 101         if (!args)
 102                 return -1;
 103         if (!(cmd = (char *)args[0]))
 104                 return -1;
 105
 106         /*
 107          * The callback can be invoked on the cpu that first dropped
 108          * into prom_cmdline after taking the serial interrupt, or on
 109          * a slave processor that was smp_captured() if the
 110          * administrator has done a switch-cpu inside obp. In either
 111          * case, the cpu is marked as in-interrupt. Drop IRQ locks.
 112          */
 113         irq_exit();
 114
 115         /* XXX Revisit the locking here someday.  This is a debugging
 116          * XXX feature so it isnt all that critical.  -DaveM
 117          */
 118         local_irq_save(flags);
 119
 120         spin_unlock(&prom_entry_lock);
 121         cons = console_drivers;
 122         while (cons) {
 123                 unregister_console(cons);
 124                 cons->flags &= ~(CON_PRINTBUFFER);
 125                 cons->next = saved_console;
 126                 saved_console = cons;
 127                 cons = console_drivers;
 128         }
 129         register_console(&prom_console);
 130         if (!strcmp(cmd, "sync")) {
 131                 prom_printf("PROM `%s' command...\n", cmd);
 132                 show_free_areas();
 133                 if (current->pid != 0) {
 134                         local_irq_enable();
 135                         sys_sync();
 136                         local_irq_disable();
 137                 }
 138                 args[2] = 0;
 139                 args[args[1] + 3] = -1;
 140                 prom_printf("Returning to PROM\n");
 141         } else if (!strcmp(cmd, "va>tte-data")) {
 142                 unsigned long ctx, va;
 143                 unsigned long tte = 0;
 144                 long res = PROM_FALSE;
 145
 146                 ctx = args[3];
 147                 va = args[4];
 148                 if (ctx) {
 149                         /*
 150                          * Find process owning ctx, lookup mapping.
 151                          */
 152                         struct task_struct *p;
 153                         struct mm_struct *mm = NULL;
 154                         pgd_t *pgdp;
 155                         pmd_t *pmdp;
 156                         pte_t *ptep;
 157
 158                         for_each_process(p) {
 159                                 mm = p->mm;
 160                                 if (CTX_HWBITS(mm->context) == ctx)
 161                                         break;
 162                         }
 163                         if (!mm ||
 164                             CTX_HWBITS(mm->context) != ctx)
 165                                 goto done;
 166
 167                         pgdp = pgd_offset(mm, va);
 168                         if (pgd_none(*pgdp))
 169                                 goto done;
 170                         pmdp = pmd_offset(pgdp, va);
 171                         if (pmd_none(*pmdp))
 172                                 goto done;
 173
 174                         /* Preemption implicitly disabled by virtue of
 175                          * being called from inside OBP.
 176                          */
 177                         ptep = pte_offset_map(pmdp, va);
 178                         if (pte_present(*ptep)) {
 179                                 tte = pte_val(*ptep);
 180                                 res = PROM_TRUE;
 181                         }
 182                         pte_unmap(ptep);
 183                         goto done;
 184                 }
 185
 186                 if ((va >= KERNBASE) && (va < (KERNBASE + (4 * 1024 * 1024)))) {
 187                         /* Spitfire Errata #32 workaround */
 188                         __asm__ __volatile__("stxa      %0, [%1] %2\n\t"
 189                                              "flush     %%g6"
 190                                              : /* No outputs */
 191                                              : "r" (0),
 192                                              "r" (PRIMARY_CONTEXT), "i" (ASI_DMMU));
 193
 194                         /*
 195                          * Locked down tlb entry.
 196                          */
 197
 198                         if (tlb_type == spitfire)
 199                                 tte = spitfire_get_dtlb_data(SPITFIRE_HIGHEST_LOCKED_TLBENT);
 200                         else if (tlb_type == cheetah || tlb_type == cheetah_plus)
 201                                 tte = cheetah_get_ldtlb_data(CHEETAH_HIGHEST_LOCKED_TLBENT);
 202
 203                         res = PROM_TRUE;
 204                         goto done;
 205                 }
 206
 207                 if (va < PGDIR_SIZE) {
 208                         /*
 209                          * vmalloc or prom_inherited mapping.
 210                          */
 211                         pgd_t *pgdp;
 212                         pmd_t *pmdp;
 213                         pte_t *ptep;
 214                         int error;
 215
 216                         if ((va >= LOW_OBP_ADDRESS) && (va < HI_OBP_ADDRESS)) {
 217                                 tte = prom_virt_to_phys(va, &error);
 218                                 if (!error)
 219                                         res = PROM_TRUE;
 220                                 goto done;
 221                         }
 222                         pgdp = pgd_offset_k(va);
 223                         if (pgd_none(*pgdp))
 224                                 goto done;
 225                         pmdp = pmd_offset(pgdp, va);
 226                         if (pmd_none(*pmdp))
 227                                 goto done;
 228
 229                         /* Preemption implicitly disabled by virtue of
 230                          * being called from inside OBP.
 231                          */
 232                         ptep = pte_offset_kernel(pmdp, va);
 233                         if (pte_present(*ptep)) {
 234                                 tte = pte_val(*ptep);
 235                                 res = PROM_TRUE;
 236                         }
 237                         goto done;
 238                 }
 239
 240                 if (va < PAGE_OFFSET) {
 241                         /*
 242                          * No mappings here.
 243                          */
 244                         goto done;
 245                 }
 246
 247                 if (va & (1UL << 40)) {
 248                         /*
 249                          * I/O page.
 250                          */
 251
 252                         tte = (__pa(va) & _PAGE_PADDR) |
 253                               _PAGE_VALID | _PAGE_SZ4MB |
 254                               _PAGE_E | _PAGE_P | _PAGE_W;
 255                         res = PROM_TRUE;
 256                         goto done;
 257                 }
 258
 259                 /*
 260                  * Normal page.
 261                  */
 262                 tte = (__pa(va) & _PAGE_PADDR) |
 263                       _PAGE_VALID | _PAGE_SZ4MB |
 264                       _PAGE_CP | _PAGE_CV | _PAGE_P | _PAGE_W;
 265                 res = PROM_TRUE;
 266
 267         done:
 268                 if (res == PROM_TRUE) {
 269                         args[2] = 3;
 270                         args[args[1] + 3] = 0;
 271                         args[args[1] + 4] = res;
 272                         args[args[1] + 5] = tte;
 273                 } else {
 274                         args[2] = 2;
 275                         args[args[1] + 3] = 0;
 276                         args[args[1] + 4] = res;
 277                 }
 278         } else if (!strcmp(cmd, ".soft1")) {
 279                 unsigned long tte;
 280
 281                 tte = args[3];
 282                 prom_printf("%lx:\"%s%s%s%s%s\" ",
 283                             (tte & _PAGE_SOFT) >> 7,
 284                             tte & _PAGE_MODIFIED ? "M" : "-",
 285                             tte & _PAGE_ACCESSED ? "A" : "-",
 286                             tte & _PAGE_READ     ? "W" : "-",
 287                             tte & _PAGE_WRITE    ? "R" : "-",
 288                             tte & _PAGE_PRESENT  ? "P" : "-");
 289
 290                 args[2] = 2;
 291                 args[args[1] + 3] = 0;
 292                 args[args[1] + 4] = PROM_TRUE;
 293         } else if (!strcmp(cmd, ".soft2")) {
 294                 unsigned long tte;
 295
 296                 tte = args[3];
 297                 prom_printf("%lx ", (tte & 0x07FC000000000000UL) >> 50);
 298
 299                 args[2] = 2;
 300                 args[args[1] + 3] = 0;
 301                 args[args[1] + 4] = PROM_TRUE;
 302         } else {
 303                 prom_printf("unknown PROM `%s' command...\n", cmd);
 304         }
 305         unregister_console(&prom_console);
 306         while (saved_console) {
 307                 cons = saved_console;
 308                 saved_console = cons->next;
 309                 register_console(cons);
 310         }
 311         spin_lock(&prom_entry_lock);
 312         local_irq_restore(flags);
 313
 314         /*
 315          * Restore in-interrupt status for a resume from obp.
 316          */
 317         irq_enter();
 318         return 0;
 319 }
 320
 321 unsigned int boot_flags = 0;
 322 #define BOOTME_DEBUG  0x1
 323 #define BOOTME_SINGLE 0x2
 324
 325 /* Exported for mm/init.c:paging_init. */
 326 unsigned long cmdline_memory_size = 0;
 327
 328 static struct console prom_debug_console = {
 329         .name =         "debug",
 330         .write =        prom_console_write,
 331         .flags =        CON_PRINTBUFFER,
 332         .index =        -1,
 333 };
 334
 335 /* XXX Implement this at some point... */
 336 void kernel_enter_debugger(void)
 337 {
 338 }
 339
 340 int obp_system_intr(void)
 341 {
 342         if (boot_flags & BOOTME_DEBUG) {
 343                 printk("OBP: system interrupted\n");
 344                 prom_halt();
 345                 return 1;
 346         }
 347         return 0;
 348 }
 349
 350 /*
 351  * Process kernel command line switches that are specific to the
 352  * SPARC or that require special low-level processing.
 353  */
 354 static void __init process_switch(char c)
 355 {
 356         switch (c) {
 357         case 'd':
 358                 boot_flags |= BOOTME_DEBUG;
 359                 break;
 360         case 's':
 361                 boot_flags |= BOOTME_SINGLE;
 362                 break;
 363         case 'h':
 364                 prom_printf("boot_flags_init: Halt!\n");
 365                 prom_halt();
 366                 break;
 367         case 'p':
 368                 /* Use PROM debug console. */
 369                 register_console(&prom_debug_console);
 370                 break;
 371         default:
 372                 printk("Unknown boot switch (-%c)\n", c);
 373                 break;
 374         }
 375 }
 376
 377 static void __init process_console(char *commands)
 378 {
 379         serial_console = 0;
 380         commands += 8;
 381         /* Linux-style serial */
 382         if (!strncmp(commands, "ttyS", 4))
 383                 serial_console = simple_strtoul(commands + 4, NULL, 10) + 1;
 384         else if (!strncmp(commands, "tty", 3)) {
 385                 char c = *(commands + 3);
 386                 /* Solaris-style serial */
 387                 if (c == 'a' || c == 'b') {
 388                         serial_console = c - 'a' + 1;
 389                         prom_printf ("Using /dev/tty%c as console.\n", c);
 390                 }
 391                 /* else Linux-style fbcon, not serial */
 392         }
 393 #if defined(CONFIG_PROM_CONSOLE)
 394         if (!strncmp(commands, "prom", 4)) {
 395                 char *p;
 396
 397                 for (p = commands - 8; *p && *p != ' '; p++)
 398                         *p = ' ';
 399                 conswitchp = &prom_con;
 400         }
 401 #endif
 402 }
 403
 404 static void __init boot_flags_init(char *commands)
 405 {
 406         while (*commands) {
 407                 /* Move to the start of the next "argument". */
 408                 while (*commands && *commands == ' ')
 409                         commands++;
 410
 411                 /* Process any command switches, otherwise skip it. */
 412                 if (*commands == '\0')
 413                         break;
 414                 if (*commands == '-') {
 415                         commands++;
 416                         while (*commands && *commands != ' ')
 417                                 process_switch(*commands++);
 418                         continue;
 419                 }
 420                 if (!strncmp(commands, "console=", 8)) {
 421                         process_console(commands);
 422                 } else if (!strncmp(commands, "mem=", 4)) {
 423                         /*
 424                          * "mem=XXX[kKmM]" overrides the PROM-reported
 425                          * memory size.
 426                          */
 427                         cmdline_memory_size = simple_strtoul(commands + 4,
 428                                                              &commands, 0);
 429                         if (*commands == 'K' || *commands == 'k') {
 430                                 cmdline_memory_size <<= 10;
 431                                 commands++;
 432                         } else if (*commands=='M' || *commands=='m') {
 433                                 cmdline_memory_size <<= 20;
 434                                 commands++;
 435                         }
 436                 }
 437                 while (*commands && *commands != ' ')
 438                         commands++;
 439         }
 440 }
 441
 442 extern int prom_probe_memory(void);
 443 extern unsigned long start, end;
 444 extern void panic_setup(char *, int *);
 445
 446 extern unsigned short root_flags;
 447 extern unsigned short root_dev;
 448 extern unsigned short ram_flags;
 449 #define RAMDISK_IMAGE_START_MASK        0x07FF
 450 #define RAMDISK_PROMPT_FLAG             0x8000
 451 #define RAMDISK_LOAD_FLAG               0x4000
 452
 453 extern int root_mountflags;
 454
 455 char reboot_command[COMMAND_LINE_SIZE];
 456
 457 static struct pt_regs fake_swapper_regs = { { 0, }, 0, 0, 0, 0 };
 458
 459 void register_prom_callbacks(void)
 460 {
 461         prom_setcallback(prom_callback);
 462         prom_feval(": linux-va>tte-data 2 \" va>tte-data\" $callback drop ; "
 463                    "' linux-va>tte-data to va>tte-data");
 464         prom_feval(": linux-.soft1 1 \" .soft1\" $callback 2drop ; "
 465                    "' linux-.soft1 to .soft1");
 466         prom_feval(": linux-.soft2 1 \" .soft2\" $callback 2drop ; "
 467                    "' linux-.soft2 to .soft2");
 468 }
 469
 470 extern void paging_init(void);
 471
 472 void __init setup_arch(char **cmdline_p)
 473 {
 474         unsigned long highest_paddr;
 475         int i;
 476
 477         /* Initialize PROM console and command line. */
 478         *cmdline_p = prom_getbootargs();
 479         strcpy(saved_command_line, *cmdline_p);
 480
 481         printk("ARCH: SUN4U\n");
 482
 483 #ifdef CONFIG_DUMMY_CONSOLE
 484         conswitchp = &dummy_con;
 485 #elif defined(CONFIG_PROM_CONSOLE)
 486         conswitchp = &prom_con;
 487 #endif
 488
 489 #ifdef CONFIG_SMP
 490         i = (unsigned long)&irq_stat[1] - (unsigned long)&irq_stat[0];
 491         if ((i == SMP_CACHE_BYTES) || (i == (2 * SMP_CACHE_BYTES))) {
 492                 extern unsigned int irqsz_patchme[1];
 493                 irqsz_patchme[0] |= ((i == SMP_CACHE_BYTES) ? SMP_CACHE_BYTES_SHIFT : \
 494                                                         SMP_CACHE_BYTES_SHIFT + 1);
 495                 flushi((long)&irqsz_patchme[0]);
 496         } else {
 497                 prom_printf("Unexpected size of irq_stat[] elements\n");
 498                 prom_halt();
 499         }
 500 #endif
 501         /* Work out if we are starfire early on */
 502         check_if_starfire();
 503
 504         boot_flags_init(*cmdline_p);
 505
 506         idprom_init();
 507         (void) prom_probe_memory();
 508
 509         /* In paging_init() we tip off this value to see if we need
 510          * to change init_mm.pgd to point to the real alias mapping.
 511          */
 512         phys_base = 0xffffffffffffffffUL;
 513         highest_paddr = 0UL;
 514         for (i = 0; sp_banks[i].num_bytes != 0; i++) {
 515                 unsigned long top;
 516
 517                 if (sp_banks[i].base_addr < phys_base)
 518                         phys_base = sp_banks[i].base_addr;
 519                 top = sp_banks[i].base_addr +
 520                         sp_banks[i].num_bytes;
 521                 if (highest_paddr < top)
 522                         highest_paddr = top;
 523         }
 524         pfn_base = phys_base >> PAGE_SHIFT;
 525
 526         switch (tlb_type) {
 527         default:
 528         case spitfire:
 529                 kern_base = spitfire_get_itlb_data(sparc64_highest_locked_tlbent());
 530                 kern_base &= _PAGE_PADDR_SF;
 531                 break;
 532
 533         case cheetah:
 534         case cheetah_plus:
 535                 kern_base = cheetah_get_litlb_data(sparc64_highest_locked_tlbent());
 536                 kern_base &= _PAGE_PADDR;
 537                 break;
 538         };
 539
 540         kern_size = (unsigned long)&_end - (unsigned long)KERNBASE;
 541
 542         if (!root_flags)
 543                 root_mountflags &= ~MS_RDONLY;
 544         ROOT_DEV = old_decode_dev(root_dev);
 545 #ifdef CONFIG_BLK_DEV_INITRD
 546         rd_image_start = ram_flags & RAMDISK_IMAGE_START_MASK;
 547         rd_prompt = ((ram_flags & RAMDISK_PROMPT_FLAG) != 0);
 548         rd_doload = ((ram_flags & RAMDISK_LOAD_FLAG) != 0);
 549 #endif
 550
 551         init_task.thread_info->kregs = &fake_swapper_regs;
 552
 553 #ifdef CONFIG_IP_PNP
 554         if (!ic_set_manually) {
 555                 int chosen = prom_finddevice ("/chosen");
 556                 u32 cl, sv, gw;
 557
 558                 cl = prom_getintdefault (chosen, "client-ip", 0);
 559                 sv = prom_getintdefault (chosen, "server-ip", 0);
 560                 gw = prom_getintdefault (chosen, "gateway-ip", 0);
 561                 if (cl && sv) {
 562                         ic_myaddr = cl;
 563                         ic_servaddr = sv;
 564                         if (gw)
 565                                 ic_gateway = gw;
 566 #if defined(CONFIG_IP_PNP_BOOTP) || defined(CONFIG_IP_PNP_RARP)
 567                         ic_proto_enabled = 0;
 568 #endif
 569                 }
 570         }
 571 #endif
 572
 573         paging_init();
 574 }
 575
 576 static int __init set_preferred_console(void)
 577 {
 578         int idev, odev;
 579
 580         /* The user has requested a console so this is already set up. */
 581         if (serial_console >= 0)
 582                 return -EBUSY;
 583
 584         idev = prom_query_input_device();
 585         odev = prom_query_output_device();
 586         if (idev == PROMDEV_IKBD && odev == PROMDEV_OSCREEN) {
 587                 serial_console = 0;
 588         } else if (idev == PROMDEV_ITTYA && odev == PROMDEV_OTTYA) {
 589                 serial_console = 1;
 590         } else if (idev == PROMDEV_ITTYB && odev == PROMDEV_OTTYB) {
 591                 serial_console = 2;
 592         } else {
 593                 prom_printf("Inconsistent console: "
 594                             "input %d, output %d\n",
 595                             idev, odev);
 596                 prom_halt();
 597         }
 598
 599         if (serial_console)
 600                 return add_preferred_console("ttyS", serial_console - 1, NULL);
 601
 602         return -ENODEV;
 603 }
 604 console_initcall(set_preferred_console);
 605
 606 /* BUFFER is PAGE_SIZE bytes long. */
 607
 608 extern char *sparc_cpu_type;
 609 extern char *sparc_fpu_type;
 610
 611 extern void smp_info(struct seq_file *);
 612 extern void smp_bogo(struct seq_file *);
 613 extern void mmu_info(struct seq_file *);
 614
 615 static int show_cpuinfo(struct seq_file *m, void *__unused)
 616 {
 617         seq_printf(m,
 618                    "cpu\t\t: %s\n"
 619                    "fpu\t\t: %s\n"
 620                    "promlib\t\t: Version 3 Revision %d\n"
 621                    "prom\t\t: %d.%d.%d\n"
 622                    "type\t\t: sun4u\n"
 623                    "ncpus probed\t: %ld\n"
 624                    "ncpus active\t: %ld\n"
 625 #ifndef CONFIG_SMP
 626                    "Cpu0Bogo\t: %lu.%02lu\n"
 627                    "Cpu0ClkTck\t: %016lx\n"
 628 #endif
 629                    ,
 630                    sparc_cpu_type,
 631                    sparc_fpu_type,
 632                    prom_rev,
 633                    prom_prev >> 16,
 634                    (prom_prev >> 8) & 0xff,
 635                    prom_prev & 0xff,
 636                    (long)num_possible_cpus(),
 637                    (long)num_online_cpus()
 638 #ifndef CONFIG_SMP
 639                    , cpu_data(0).udelay_val/(500000/HZ),
 640                    (cpu_data(0).udelay_val/(5000/HZ)) % 100,
 641                    cpu_data(0).clock_tick
 642 #endif
 643                 );
 644 #ifdef CONFIG_SMP
 645         smp_bogo(m);
 646 #endif
 647         mmu_info(m);
 648 #ifdef CONFIG_SMP
 649         smp_info(m);
 650 #endif
 651         return 0;
 652 }
 653
 654 static void *c_start(struct seq_file *m, loff_t *pos)
 655 {
 656         /* The pointer we are returning is arbitrary,
 657          * it just has to be non-NULL and not IS_ERR
 658          * in the success case.
 659          */
 660         return *pos == 0 ? &c_start : NULL;
 661 }
 662
 663 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 664 {
 665         ++*pos;
 666         return c_start(m, pos);
 667 }
 668
 669 static void c_stop(struct seq_file *m, void *v)
 670 {
 671 }
 672
 673 struct seq_operations cpuinfo_op = {
 674         .start =c_start,
 675         .next = c_next,
 676         .stop = c_stop,
 677         .show = show_cpuinfo,
 678 };
 679
 680 extern int stop_a_enabled;
 681
 682 void sun_do_break(void)
 683 {
 684         if (!stop_a_enabled)
 685                 return;
 686
 687         prom_printf("\n");
 688         flush_user_windows();
 689
 690         prom_cmdline();
 691 }
 692
 693 int serial_console = -1;
 694 int stop_a_enabled = 1;
 695
 696 static int __init topology_init(void)
 697 {
 698         int i, err;
 699
 700         err = -ENOMEM;
 701         for (i = 0; i < NR_CPUS; i++) {
 702                 if (cpu_possible(i)) {
 703                         struct cpu *p = kmalloc(sizeof(*p), GFP_KERNEL);
 704
 705                         if (p) {
 706                                 memset(p, 0, sizeof(*p));
 707                                 register_cpu(p, i, NULL);
 708                                 err = 0;
 709                         }
 710                 }
 711         }
 712
 713         return err;
 714 }
 715
 716 subsys_initcall(topology_init);