linux/arch/ia64/kernel/process.c
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   1/*
   2 * Architecture-specific setup.
   3 *
   4 * Copyright (C) 1998-2003 Hewlett-Packard Co
   5 *      David Mosberger-Tang <davidm@hpl.hp.com>
   6 * 04/11/17 Ashok Raj   <ashok.raj@intel.com> Added CPU Hotplug Support
   7 *
   8 * 2005-10-07 Keith Owens <kaos@sgi.com>
   9 *            Add notify_die() hooks.
  10 */
  11#include <linux/cpu.h>
  12#include <linux/pm.h>
  13#include <linux/elf.h>
  14#include <linux/errno.h>
  15#include <linux/kallsyms.h>
  16#include <linux/kernel.h>
  17#include <linux/mm.h>
  18#include <linux/slab.h>
  19#include <linux/module.h>
  20#include <linux/notifier.h>
  21#include <linux/personality.h>
  22#include <linux/sched.h>
  23#include <linux/stddef.h>
  24#include <linux/thread_info.h>
  25#include <linux/unistd.h>
  26#include <linux/efi.h>
  27#include <linux/interrupt.h>
  28#include <linux/delay.h>
  29#include <linux/kdebug.h>
  30#include <linux/utsname.h>
  31#include <linux/tracehook.h>
  32#include <linux/rcupdate.h>
  33
  34#include <asm/cpu.h>
  35#include <asm/delay.h>
  36#include <asm/elf.h>
  37#include <asm/irq.h>
  38#include <asm/kexec.h>
  39#include <asm/pgalloc.h>
  40#include <asm/processor.h>
  41#include <asm/sal.h>
  42#include <asm/switch_to.h>
  43#include <asm/tlbflush.h>
  44#include <asm/uaccess.h>
  45#include <asm/unwind.h>
  46#include <asm/user.h>
  47
  48#include "entry.h"
  49
  50#ifdef CONFIG_PERFMON
  51# include <asm/perfmon.h>
  52#endif
  53
  54#include "sigframe.h"
  55
  56void (*ia64_mark_idle)(int);
  57
  58unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;
  59EXPORT_SYMBOL(boot_option_idle_override);
  60void (*pm_power_off) (void);
  61EXPORT_SYMBOL(pm_power_off);
  62
  63void
  64ia64_do_show_stack (struct unw_frame_info *info, void *arg)
  65{
  66        unsigned long ip, sp, bsp;
  67        char buf[128];                  /* don't make it so big that it overflows the stack! */
  68
  69        printk("\nCall Trace:\n");
  70        do {
  71                unw_get_ip(info, &ip);
  72                if (ip == 0)
  73                        break;
  74
  75                unw_get_sp(info, &sp);
  76                unw_get_bsp(info, &bsp);
  77                snprintf(buf, sizeof(buf),
  78                         " [<%016lx>] %%s\n"
  79                         "                                sp=%016lx bsp=%016lx\n",
  80                         ip, sp, bsp);
  81                print_symbol(buf, ip);
  82        } while (unw_unwind(info) >= 0);
  83}
  84
  85void
  86show_stack (struct task_struct *task, unsigned long *sp)
  87{
  88        if (!task)
  89                unw_init_running(ia64_do_show_stack, NULL);
  90        else {
  91                struct unw_frame_info info;
  92
  93                unw_init_from_blocked_task(&info, task);
  94                ia64_do_show_stack(&info, NULL);
  95        }
  96}
  97
  98void
  99show_regs (struct pt_regs *regs)
 100{
 101        unsigned long ip = regs->cr_iip + ia64_psr(regs)->ri;
 102
 103        print_modules();
 104        printk("\n");
 105        show_regs_print_info(KERN_DEFAULT);
 106        printk("psr : %016lx ifs : %016lx ip  : [<%016lx>]    %s (%s)\n",
 107               regs->cr_ipsr, regs->cr_ifs, ip, print_tainted(),
 108               init_utsname()->release);
 109        print_symbol("ip is at %s\n", ip);
 110        printk("unat: %016lx pfs : %016lx rsc : %016lx\n",
 111               regs->ar_unat, regs->ar_pfs, regs->ar_rsc);
 112        printk("rnat: %016lx bsps: %016lx pr  : %016lx\n",
 113               regs->ar_rnat, regs->ar_bspstore, regs->pr);
 114        printk("ldrs: %016lx ccv : %016lx fpsr: %016lx\n",
 115               regs->loadrs, regs->ar_ccv, regs->ar_fpsr);
 116        printk("csd : %016lx ssd : %016lx\n", regs->ar_csd, regs->ar_ssd);
 117        printk("b0  : %016lx b6  : %016lx b7  : %016lx\n", regs->b0, regs->b6, regs->b7);
 118        printk("f6  : %05lx%016lx f7  : %05lx%016lx\n",
 119               regs->f6.u.bits[1], regs->f6.u.bits[0],
 120               regs->f7.u.bits[1], regs->f7.u.bits[0]);
 121        printk("f8  : %05lx%016lx f9  : %05lx%016lx\n",
 122               regs->f8.u.bits[1], regs->f8.u.bits[0],
 123               regs->f9.u.bits[1], regs->f9.u.bits[0]);
 124        printk("f10 : %05lx%016lx f11 : %05lx%016lx\n",
 125               regs->f10.u.bits[1], regs->f10.u.bits[0],
 126               regs->f11.u.bits[1], regs->f11.u.bits[0]);
 127
 128        printk("r1  : %016lx r2  : %016lx r3  : %016lx\n", regs->r1, regs->r2, regs->r3);
 129        printk("r8  : %016lx r9  : %016lx r10 : %016lx\n", regs->r8, regs->r9, regs->r10);
 130        printk("r11 : %016lx r12 : %016lx r13 : %016lx\n", regs->r11, regs->r12, regs->r13);
 131        printk("r14 : %016lx r15 : %016lx r16 : %016lx\n", regs->r14, regs->r15, regs->r16);
 132        printk("r17 : %016lx r18 : %016lx r19 : %016lx\n", regs->r17, regs->r18, regs->r19);
 133        printk("r20 : %016lx r21 : %016lx r22 : %016lx\n", regs->r20, regs->r21, regs->r22);
 134        printk("r23 : %016lx r24 : %016lx r25 : %016lx\n", regs->r23, regs->r24, regs->r25);
 135        printk("r26 : %016lx r27 : %016lx r28 : %016lx\n", regs->r26, regs->r27, regs->r28);
 136        printk("r29 : %016lx r30 : %016lx r31 : %016lx\n", regs->r29, regs->r30, regs->r31);
 137
 138        if (user_mode(regs)) {
 139                /* print the stacked registers */
 140                unsigned long val, *bsp, ndirty;
 141                int i, sof, is_nat = 0;
 142
 143                sof = regs->cr_ifs & 0x7f;      /* size of frame */
 144                ndirty = (regs->loadrs >> 19);
 145                bsp = ia64_rse_skip_regs((unsigned long *) regs->ar_bspstore, ndirty);
 146                for (i = 0; i < sof; ++i) {
 147                        get_user(val, (unsigned long __user *) ia64_rse_skip_regs(bsp, i));
 148                        printk("r%-3u:%c%016lx%s", 32 + i, is_nat ? '*' : ' ', val,
 149                               ((i == sof - 1) || (i % 3) == 2) ? "\n" : " ");
 150                }
 151        } else
 152                show_stack(NULL, NULL);
 153}
 154
 155/* local support for deprecated console_print */
 156void
 157console_print(const char *s)
 158{
 159        printk(KERN_EMERG "%s", s);
 160}
 161
 162void
 163do_notify_resume_user(sigset_t *unused, struct sigscratch *scr, long in_syscall)
 164{
 165        if (fsys_mode(current, &scr->pt)) {
 166                /*
 167                 * defer signal-handling etc. until we return to
 168                 * privilege-level 0.
 169                 */
 170                if (!ia64_psr(&scr->pt)->lp)
 171                        ia64_psr(&scr->pt)->lp = 1;
 172                return;
 173        }
 174
 175#ifdef CONFIG_PERFMON
 176        if (current->thread.pfm_needs_checking)
 177                /*
 178                 * Note: pfm_handle_work() allow us to call it with interrupts
 179                 * disabled, and may enable interrupts within the function.
 180                 */
 181                pfm_handle_work();
 182#endif
 183
 184        /* deal with pending signal delivery */
 185        if (test_thread_flag(TIF_SIGPENDING)) {
 186                local_irq_enable();     /* force interrupt enable */
 187                ia64_do_signal(scr, in_syscall);
 188        }
 189
 190        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
 191                local_irq_enable();     /* force interrupt enable */
 192                tracehook_notify_resume(&scr->pt);
 193        }
 194
 195        /* copy user rbs to kernel rbs */
 196        if (unlikely(test_thread_flag(TIF_RESTORE_RSE))) {
 197                local_irq_enable();     /* force interrupt enable */
 198                ia64_sync_krbs();
 199        }
 200
 201        local_irq_disable();    /* force interrupt disable */
 202}
 203
 204static int __init nohalt_setup(char * str)
 205{
 206        cpu_idle_poll_ctrl(true);
 207        return 1;
 208}
 209__setup("nohalt", nohalt_setup);
 210
 211#ifdef CONFIG_HOTPLUG_CPU
 212/* We don't actually take CPU down, just spin without interrupts. */
 213static inline void play_dead(void)
 214{
 215        unsigned int this_cpu = smp_processor_id();
 216
 217        /* Ack it */
 218        __get_cpu_var(cpu_state) = CPU_DEAD;
 219
 220        max_xtp();
 221        local_irq_disable();
 222        idle_task_exit();
 223        ia64_jump_to_sal(&sal_boot_rendez_state[this_cpu]);
 224        /*
 225         * The above is a point of no-return, the processor is
 226         * expected to be in SAL loop now.
 227         */
 228        BUG();
 229}
 230#else
 231static inline void play_dead(void)
 232{
 233        BUG();
 234}
 235#endif /* CONFIG_HOTPLUG_CPU */
 236
 237void arch_cpu_idle_dead(void)
 238{
 239        play_dead();
 240}
 241
 242void arch_cpu_idle(void)
 243{
 244        void (*mark_idle)(int) = ia64_mark_idle;
 245
 246#ifdef CONFIG_SMP
 247        min_xtp();
 248#endif
 249        rmb();
 250        if (mark_idle)
 251                (*mark_idle)(1);
 252
 253        safe_halt();
 254
 255        if (mark_idle)
 256                (*mark_idle)(0);
 257#ifdef CONFIG_SMP
 258        normal_xtp();
 259#endif
 260}
 261
 262void
 263ia64_save_extra (struct task_struct *task)
 264{
 265#ifdef CONFIG_PERFMON
 266        unsigned long info;
 267#endif
 268
 269        if ((task->thread.flags & IA64_THREAD_DBG_VALID) != 0)
 270                ia64_save_debug_regs(&task->thread.dbr[0]);
 271
 272#ifdef CONFIG_PERFMON
 273        if ((task->thread.flags & IA64_THREAD_PM_VALID) != 0)
 274                pfm_save_regs(task);
 275
 276        info = __get_cpu_var(pfm_syst_info);
 277        if (info & PFM_CPUINFO_SYST_WIDE)
 278                pfm_syst_wide_update_task(task, info, 0);
 279#endif
 280}
 281
 282void
 283ia64_load_extra (struct task_struct *task)
 284{
 285#ifdef CONFIG_PERFMON
 286        unsigned long info;
 287#endif
 288
 289        if ((task->thread.flags & IA64_THREAD_DBG_VALID) != 0)
 290                ia64_load_debug_regs(&task->thread.dbr[0]);
 291
 292#ifdef CONFIG_PERFMON
 293        if ((task->thread.flags & IA64_THREAD_PM_VALID) != 0)
 294                pfm_load_regs(task);
 295
 296        info = __get_cpu_var(pfm_syst_info);
 297        if (info & PFM_CPUINFO_SYST_WIDE) 
 298                pfm_syst_wide_update_task(task, info, 1);
 299#endif
 300}
 301
 302/*
 303 * Copy the state of an ia-64 thread.
 304 *
 305 * We get here through the following  call chain:
 306 *
 307 *      from user-level:        from kernel:
 308 *
 309 *      <clone syscall>         <some kernel call frames>
 310 *      sys_clone                  :
 311 *      do_fork                 do_fork
 312 *      copy_thread             copy_thread
 313 *
 314 * This means that the stack layout is as follows:
 315 *
 316 *      +---------------------+ (highest addr)
 317 *      |   struct pt_regs    |
 318 *      +---------------------+
 319 *      | struct switch_stack |
 320 *      +---------------------+
 321 *      |                     |
 322 *      |    memory stack     |
 323 *      |                     | <-- sp (lowest addr)
 324 *      +---------------------+
 325 *
 326 * Observe that we copy the unat values that are in pt_regs and switch_stack.  Spilling an
 327 * integer to address X causes bit N in ar.unat to be set to the NaT bit of the register,
 328 * with N=(X & 0x1ff)/8.  Thus, copying the unat value preserves the NaT bits ONLY if the
 329 * pt_regs structure in the parent is congruent to that of the child, modulo 512.  Since
 330 * the stack is page aligned and the page size is at least 4KB, this is always the case,
 331 * so there is nothing to worry about.
 332 */
 333int
 334copy_thread(unsigned long clone_flags,
 335             unsigned long user_stack_base, unsigned long user_stack_size,
 336             struct task_struct *p)
 337{
 338        extern char ia64_ret_from_clone;
 339        struct switch_stack *child_stack, *stack;
 340        unsigned long rbs, child_rbs, rbs_size;
 341        struct pt_regs *child_ptregs;
 342        struct pt_regs *regs = current_pt_regs();
 343        int retval = 0;
 344
 345        child_ptregs = (struct pt_regs *) ((unsigned long) p + IA64_STK_OFFSET) - 1;
 346        child_stack = (struct switch_stack *) child_ptregs - 1;
 347
 348        rbs = (unsigned long) current + IA64_RBS_OFFSET;
 349        child_rbs = (unsigned long) p + IA64_RBS_OFFSET;
 350
 351        /* copy parts of thread_struct: */
 352        p->thread.ksp = (unsigned long) child_stack - 16;
 353
 354        /*
 355         * NOTE: The calling convention considers all floating point
 356         * registers in the high partition (fph) to be scratch.  Since
 357         * the only way to get to this point is through a system call,
 358         * we know that the values in fph are all dead.  Hence, there
 359         * is no need to inherit the fph state from the parent to the
 360         * child and all we have to do is to make sure that
 361         * IA64_THREAD_FPH_VALID is cleared in the child.
 362         *
 363         * XXX We could push this optimization a bit further by
 364         * clearing IA64_THREAD_FPH_VALID on ANY system call.
 365         * However, it's not clear this is worth doing.  Also, it
 366         * would be a slight deviation from the normal Linux system
 367         * call behavior where scratch registers are preserved across
 368         * system calls (unless used by the system call itself).
 369         */
 370#       define THREAD_FLAGS_TO_CLEAR    (IA64_THREAD_FPH_VALID | IA64_THREAD_DBG_VALID \
 371                                         | IA64_THREAD_PM_VALID)
 372#       define THREAD_FLAGS_TO_SET      0
 373        p->thread.flags = ((current->thread.flags & ~THREAD_FLAGS_TO_CLEAR)
 374                           | THREAD_FLAGS_TO_SET);
 375
 376        ia64_drop_fpu(p);       /* don't pick up stale state from a CPU's fph */
 377
 378        if (unlikely(p->flags & PF_KTHREAD)) {
 379                if (unlikely(!user_stack_base)) {
 380                        /* fork_idle() called us */
 381                        return 0;
 382                }
 383                memset(child_stack, 0, sizeof(*child_ptregs) + sizeof(*child_stack));
 384                child_stack->r4 = user_stack_base;      /* payload */
 385                child_stack->r5 = user_stack_size;      /* argument */
 386                /*
 387                 * Preserve PSR bits, except for bits 32-34 and 37-45,
 388                 * which we can't read.
 389                 */
 390                child_ptregs->cr_ipsr = ia64_getreg(_IA64_REG_PSR) | IA64_PSR_BN;
 391                /* mark as valid, empty frame */
 392                child_ptregs->cr_ifs = 1UL << 63;
 393                child_stack->ar_fpsr = child_ptregs->ar_fpsr
 394                        = ia64_getreg(_IA64_REG_AR_FPSR);
 395                child_stack->pr = (1 << PRED_KERNEL_STACK);
 396                child_stack->ar_bspstore = child_rbs;
 397                child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
 398
 399                /* stop some PSR bits from being inherited.
 400                 * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
 401                 * therefore we must specify them explicitly here and not include them in
 402                 * IA64_PSR_BITS_TO_CLEAR.
 403                 */
 404                child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
 405                                 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
 406
 407                return 0;
 408        }
 409        stack = ((struct switch_stack *) regs) - 1;
 410        /* copy parent's switch_stack & pt_regs to child: */
 411        memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack));
 412
 413        /* copy the parent's register backing store to the child: */
 414        rbs_size = stack->ar_bspstore - rbs;
 415        memcpy((void *) child_rbs, (void *) rbs, rbs_size);
 416        if (clone_flags & CLONE_SETTLS)
 417                child_ptregs->r13 = regs->r16;  /* see sys_clone2() in entry.S */
 418        if (user_stack_base) {
 419                child_ptregs->r12 = user_stack_base + user_stack_size - 16;
 420                child_ptregs->ar_bspstore = user_stack_base;
 421                child_ptregs->ar_rnat = 0;
 422                child_ptregs->loadrs = 0;
 423        }
 424        child_stack->ar_bspstore = child_rbs + rbs_size;
 425        child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
 426
 427        /* stop some PSR bits from being inherited.
 428         * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
 429         * therefore we must specify them explicitly here and not include them in
 430         * IA64_PSR_BITS_TO_CLEAR.
 431         */
 432        child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
 433                                 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
 434
 435#ifdef CONFIG_PERFMON
 436        if (current->thread.pfm_context)
 437                pfm_inherit(p, child_ptregs);
 438#endif
 439        return retval;
 440}
 441
 442static void
 443do_copy_task_regs (struct task_struct *task, struct unw_frame_info *info, void *arg)
 444{
 445        unsigned long mask, sp, nat_bits = 0, ar_rnat, urbs_end, cfm;
 446        unsigned long uninitialized_var(ip);    /* GCC be quiet */
 447        elf_greg_t *dst = arg;
 448        struct pt_regs *pt;
 449        char nat;
 450        int i;
 451
 452        memset(dst, 0, sizeof(elf_gregset_t));  /* don't leak any kernel bits to user-level */
 453
 454        if (unw_unwind_to_user(info) < 0)
 455                return;
 456
 457        unw_get_sp(info, &sp);
 458        pt = (struct pt_regs *) (sp + 16);
 459
 460        urbs_end = ia64_get_user_rbs_end(task, pt, &cfm);
 461
 462        if (ia64_sync_user_rbs(task, info->sw, pt->ar_bspstore, urbs_end) < 0)
 463                return;
 464
 465        ia64_peek(task, info->sw, urbs_end, (long) ia64_rse_rnat_addr((long *) urbs_end),
 466                  &ar_rnat);
 467
 468        /*
 469         * coredump format:
 470         *      r0-r31
 471         *      NaT bits (for r0-r31; bit N == 1 iff rN is a NaT)
 472         *      predicate registers (p0-p63)
 473         *      b0-b7
 474         *      ip cfm user-mask
 475         *      ar.rsc ar.bsp ar.bspstore ar.rnat
 476         *      ar.ccv ar.unat ar.fpsr ar.pfs ar.lc ar.ec
 477         */
 478
 479        /* r0 is zero */
 480        for (i = 1, mask = (1UL << i); i < 32; ++i) {
 481                unw_get_gr(info, i, &dst[i], &nat);
 482                if (nat)
 483                        nat_bits |= mask;
 484                mask <<= 1;
 485        }
 486        dst[32] = nat_bits;
 487        unw_get_pr(info, &dst[33]);
 488
 489        for (i = 0; i < 8; ++i)
 490                unw_get_br(info, i, &dst[34 + i]);
 491
 492        unw_get_rp(info, &ip);
 493        dst[42] = ip + ia64_psr(pt)->ri;
 494        dst[43] = cfm;
 495        dst[44] = pt->cr_ipsr & IA64_PSR_UM;
 496
 497        unw_get_ar(info, UNW_AR_RSC, &dst[45]);
 498        /*
 499         * For bsp and bspstore, unw_get_ar() would return the kernel
 500         * addresses, but we need the user-level addresses instead:
 501         */
 502        dst[46] = urbs_end;     /* note: by convention PT_AR_BSP points to the end of the urbs! */
 503        dst[47] = pt->ar_bspstore;
 504        dst[48] = ar_rnat;
 505        unw_get_ar(info, UNW_AR_CCV, &dst[49]);
 506        unw_get_ar(info, UNW_AR_UNAT, &dst[50]);
 507        unw_get_ar(info, UNW_AR_FPSR, &dst[51]);
 508        dst[52] = pt->ar_pfs;   /* UNW_AR_PFS is == to pt->cr_ifs for interrupt frames */
 509        unw_get_ar(info, UNW_AR_LC, &dst[53]);
 510        unw_get_ar(info, UNW_AR_EC, &dst[54]);
 511        unw_get_ar(info, UNW_AR_CSD, &dst[55]);
 512        unw_get_ar(info, UNW_AR_SSD, &dst[56]);
 513}
 514
 515void
 516do_dump_task_fpu (struct task_struct *task, struct unw_frame_info *info, void *arg)
 517{
 518        elf_fpreg_t *dst = arg;
 519        int i;
 520
 521        memset(dst, 0, sizeof(elf_fpregset_t)); /* don't leak any "random" bits */
 522
 523        if (unw_unwind_to_user(info) < 0)
 524                return;
 525
 526        /* f0 is 0.0, f1 is 1.0 */
 527
 528        for (i = 2; i < 32; ++i)
 529                unw_get_fr(info, i, dst + i);
 530
 531        ia64_flush_fph(task);
 532        if ((task->thread.flags & IA64_THREAD_FPH_VALID) != 0)
 533                memcpy(dst + 32, task->thread.fph, 96*16);
 534}
 535
 536void
 537do_copy_regs (struct unw_frame_info *info, void *arg)
 538{
 539        do_copy_task_regs(current, info, arg);
 540}
 541
 542void
 543do_dump_fpu (struct unw_frame_info *info, void *arg)
 544{
 545        do_dump_task_fpu(current, info, arg);
 546}
 547
 548void
 549ia64_elf_core_copy_regs (struct pt_regs *pt, elf_gregset_t dst)
 550{
 551        unw_init_running(do_copy_regs, dst);
 552}
 553
 554int
 555dump_fpu (struct pt_regs *pt, elf_fpregset_t dst)
 556{
 557        unw_init_running(do_dump_fpu, dst);
 558        return 1;       /* f0-f31 are always valid so we always return 1 */
 559}
 560
 561/*
 562 * Flush thread state.  This is called when a thread does an execve().
 563 */
 564void
 565flush_thread (void)
 566{
 567        /* drop floating-point and debug-register state if it exists: */
 568        current->thread.flags &= ~(IA64_THREAD_FPH_VALID | IA64_THREAD_DBG_VALID);
 569        ia64_drop_fpu(current);
 570}
 571
 572/*
 573 * Clean up state associated with current thread.  This is called when
 574 * the thread calls exit().
 575 */
 576void
 577exit_thread (void)
 578{
 579
 580        ia64_drop_fpu(current);
 581#ifdef CONFIG_PERFMON
 582       /* if needed, stop monitoring and flush state to perfmon context */
 583        if (current->thread.pfm_context)
 584                pfm_exit_thread(current);
 585
 586        /* free debug register resources */
 587        if (current->thread.flags & IA64_THREAD_DBG_VALID)
 588                pfm_release_debug_registers(current);
 589#endif
 590}
 591
 592unsigned long
 593get_wchan (struct task_struct *p)
 594{
 595        struct unw_frame_info info;
 596        unsigned long ip;
 597        int count = 0;
 598
 599        if (!p || p == current || p->state == TASK_RUNNING)
 600                return 0;
 601
 602        /*
 603         * Note: p may not be a blocked task (it could be current or
 604         * another process running on some other CPU.  Rather than
 605         * trying to determine if p is really blocked, we just assume
 606         * it's blocked and rely on the unwind routines to fail
 607         * gracefully if the process wasn't really blocked after all.
 608         * --davidm 99/12/15
 609         */
 610        unw_init_from_blocked_task(&info, p);
 611        do {
 612                if (p->state == TASK_RUNNING)
 613                        return 0;
 614                if (unw_unwind(&info) < 0)
 615                        return 0;
 616                unw_get_ip(&info, &ip);
 617                if (!in_sched_functions(ip))
 618                        return ip;
 619        } while (count++ < 16);
 620        return 0;
 621}
 622
 623void
 624cpu_halt (void)
 625{
 626        pal_power_mgmt_info_u_t power_info[8];
 627        unsigned long min_power;
 628        int i, min_power_state;
 629
 630        if (ia64_pal_halt_info(power_info) != 0)
 631                return;
 632
 633        min_power_state = 0;
 634        min_power = power_info[0].pal_power_mgmt_info_s.power_consumption;
 635        for (i = 1; i < 8; ++i)
 636                if (power_info[i].pal_power_mgmt_info_s.im
 637                    && power_info[i].pal_power_mgmt_info_s.power_consumption < min_power) {
 638                        min_power = power_info[i].pal_power_mgmt_info_s.power_consumption;
 639                        min_power_state = i;
 640                }
 641
 642        while (1)
 643                ia64_pal_halt(min_power_state);
 644}
 645
 646void machine_shutdown(void)
 647{
 648#ifdef CONFIG_HOTPLUG_CPU
 649        int cpu;
 650
 651        for_each_online_cpu(cpu) {
 652                if (cpu != smp_processor_id())
 653                        cpu_down(cpu);
 654        }
 655#endif
 656#ifdef CONFIG_KEXEC
 657        kexec_disable_iosapic();
 658#endif
 659}
 660
 661void
 662machine_restart (char *restart_cmd)
 663{
 664        (void) notify_die(DIE_MACHINE_RESTART, restart_cmd, NULL, 0, 0, 0);
 665        efi_reboot(REBOOT_WARM, NULL);
 666}
 667
 668void
 669machine_halt (void)
 670{
 671        (void) notify_die(DIE_MACHINE_HALT, "", NULL, 0, 0, 0);
 672        cpu_halt();
 673}
 674
 675void
 676machine_power_off (void)
 677{
 678        if (pm_power_off)
 679                pm_power_off();
 680        machine_halt();
 681}
 682
 683