arch/sparc/kernel/process_64.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*  arch/sparc64/kernel/process.c
   3  *
   4  *  Copyright (C) 1995, 1996, 2008 David S. Miller (davem@davemloft.net)
   5  *  Copyright (C) 1996       Eddie C. Dost   (ecd@skynet.be)
   6  *  Copyright (C) 1997, 1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
   7  */
   8
   9 /*
  10  * This file handles the architecture-dependent parts of process handling..
  11  */
  12 #include <linux/errno.h>
  13 #include <linux/export.h>
  14 #include <linux/sched.h>
  15 #include <linux/sched/debug.h>
  16 #include <linux/sched/task.h>
  17 #include <linux/sched/task_stack.h>
  18 #include <linux/kernel.h>
  19 #include <linux/mm.h>
  20 #include <linux/fs.h>
  21 #include <linux/smp.h>
  22 #include <linux/stddef.h>
  23 #include <linux/ptrace.h>
  24 #include <linux/slab.h>
  25 #include <linux/user.h>
  26 #include <linux/delay.h>
  27 #include <linux/compat.h>
  28 #include <linux/tick.h>
  29 #include <linux/init.h>
  30 #include <linux/cpu.h>
  31 #include <linux/perf_event.h>
  32 #include <linux/elfcore.h>
  33 #include <linux/sysrq.h>
  34 #include <linux/nmi.h>
  35 #include <linux/context_tracking.h>
  36 #include <linux/signal.h>
  37
  38 #include <linux/uaccess.h>
  39 #include <asm/page.h>
  40 #include <asm/pgalloc.h>
  41 #include <asm/processor.h>
  42 #include <asm/pstate.h>
  43 #include <asm/elf.h>
  44 #include <asm/fpumacro.h>
  45 #include <asm/head.h>
  46 #include <asm/cpudata.h>
  47 #include <asm/mmu_context.h>
  48 #include <asm/unistd.h>
  49 #include <asm/hypervisor.h>
  50 #include <asm/syscalls.h>
  51 #include <asm/irq_regs.h>
  52 #include <asm/smp.h>
  53 #include <asm/pcr.h>
  54
  55 #include "kstack.h"
  56
  57 /* Idle loop support on sparc64. */
  58 void arch_cpu_idle(void)
  59 {
  60         if (tlb_type != hypervisor) {
  61                 touch_nmi_watchdog();
  62         } else {
  63                 unsigned long pstate;
  64
  65                 raw_local_irq_enable();
  66
  67                 /* The sun4v sleeping code requires that we have PSTATE.IE cleared over
  68                  * the cpu sleep hypervisor call.
  69                  */
  70                 __asm__ __volatile__(
  71                         "rdpr %%pstate, %0\n\t"
  72                         "andn %0, %1, %0\n\t"
  73                         "wrpr %0, %%g0, %%pstate"
  74                         : "=&r" (pstate)
  75                         : "i" (PSTATE_IE));
  76
  77                 if (!need_resched() && !cpu_is_offline(smp_processor_id())) {
  78                         sun4v_cpu_yield();
  79                         /* If resumed by cpu_poke then we need to explicitly
  80                          * call scheduler_ipi().
  81                          */
  82                         scheduler_poke();
  83                 }
  84
  85                 /* Re-enable interrupts. */
  86                 __asm__ __volatile__(
  87                         "rdpr %%pstate, %0\n\t"
  88                         "or %0, %1, %0\n\t"
  89                         "wrpr %0, %%g0, %%pstate"
  90                         : "=&r" (pstate)
  91                         : "i" (PSTATE_IE));
  92
  93                 raw_local_irq_disable();
  94         }
  95 }
  96
  97 #ifdef CONFIG_HOTPLUG_CPU
  98 void __noreturn arch_cpu_idle_dead(void)
  99 {
 100         sched_preempt_enable_no_resched();
 101         cpu_play_dead();
 102 }
 103 #endif
 104
 105 #ifdef CONFIG_COMPAT
 106 static void show_regwindow32(struct pt_regs *regs)
 107 {
 108         struct reg_window32 __user *rw;
 109         struct reg_window32 r_w;
 110
 111         __asm__ __volatile__ ("flushw");
 112         rw = compat_ptr((unsigned int)regs->u_regs[14]);
 113         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 114                 return;
 115         }
 116
 117         printk("l0: %08x l1: %08x l2: %08x l3: %08x "
 118                "l4: %08x l5: %08x l6: %08x l7: %08x\n",
 119                r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
 120                r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
 121         printk("i0: %08x i1: %08x i2: %08x i3: %08x "
 122                "i4: %08x i5: %08x i6: %08x i7: %08x\n",
 123                r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
 124                r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
 125 }
 126 #else
 127 #define show_regwindow32(regs)  do { } while (0)
 128 #endif
 129
 130 static void show_regwindow(struct pt_regs *regs)
 131 {
 132         struct reg_window __user *rw;
 133         struct reg_window *rwk;
 134         struct reg_window r_w;
 135
 136         if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
 137                 __asm__ __volatile__ ("flushw");
 138                 rw = (struct reg_window __user *)
 139                         (regs->u_regs[14] + STACK_BIAS);
 140                 rwk = (struct reg_window *)
 141                         (regs->u_regs[14] + STACK_BIAS);
 142                 if (!(regs->tstate & TSTATE_PRIV)) {
 143                         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 144                                 return;
 145                         }
 146                         rwk = &r_w;
 147                 }
 148         } else {
 149                 show_regwindow32(regs);
 150                 return;
 151         }
 152         printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
 153                rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
 154         printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
 155                rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
 156         printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
 157                rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
 158         printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
 159                rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
 160         if (regs->tstate & TSTATE_PRIV)
 161                 printk("I7: <%pS>\n", (void *) rwk->ins[7]);
 162 }
 163
 164 void show_regs(struct pt_regs *regs)
 165 {
 166         show_regs_print_info(KERN_DEFAULT);
 167
 168         printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
 169                regs->tpc, regs->tnpc, regs->y, print_tainted());
 170         printk("TPC: <%pS>\n", (void *) regs->tpc);
 171         printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
 172                regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
 173                regs->u_regs[3]);
 174         printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
 175                regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
 176                regs->u_regs[7]);
 177         printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
 178                regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
 179                regs->u_regs[11]);
 180         printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
 181                regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
 182                regs->u_regs[15]);
 183         printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
 184         show_regwindow(regs);
 185         show_stack(current, (unsigned long *)regs->u_regs[UREG_FP], KERN_DEFAULT);
 186 }
 187
 188 union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
 189 static DEFINE_SPINLOCK(global_cpu_snapshot_lock);
 190
 191 static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
 192                               int this_cpu)
 193 {
 194         struct global_reg_snapshot *rp;
 195
 196         flushw_all();
 197
 198         rp = &global_cpu_snapshot[this_cpu].reg;
 199
 200         rp->tstate = regs->tstate;
 201         rp->tpc = regs->tpc;
 202         rp->tnpc = regs->tnpc;
 203         rp->o7 = regs->u_regs[UREG_I7];
 204
 205         if (regs->tstate & TSTATE_PRIV) {
 206                 struct reg_window *rw;
 207
 208                 rw = (struct reg_window *)
 209                         (regs->u_regs[UREG_FP] + STACK_BIAS);
 210                 if (kstack_valid(tp, (unsigned long) rw)) {
 211                         rp->i7 = rw->ins[7];
 212                         rw = (struct reg_window *)
 213                                 (rw->ins[6] + STACK_BIAS);
 214                         if (kstack_valid(tp, (unsigned long) rw))
 215                                 rp->rpc = rw->ins[7];
 216                 }
 217         } else {
 218                 rp->i7 = 0;
 219                 rp->rpc = 0;
 220         }
 221         rp->thread = tp;
 222 }
 223
 224 /* In order to avoid hangs we do not try to synchronize with the
 225  * global register dump client cpus.  The last store they make is to
 226  * the thread pointer, so do a short poll waiting for that to become
 227  * non-NULL.
 228  */
 229 static void __global_reg_poll(struct global_reg_snapshot *gp)
 230 {
 231         int limit = 0;
 232
 233         while (!gp->thread && ++limit < 100) {
 234                 barrier();
 235                 udelay(1);
 236         }
 237 }
 238
 239 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu)
 240 {
 241         struct thread_info *tp = current_thread_info();
 242         struct pt_regs *regs = get_irq_regs();
 243         unsigned long flags;
 244         int this_cpu, cpu;
 245
 246         if (!regs)
 247                 regs = tp->kregs;
 248
 249         spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
 250
 251         this_cpu = raw_smp_processor_id();
 252
 253         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 254
 255         if (cpumask_test_cpu(this_cpu, mask) && this_cpu != exclude_cpu)
 256                 __global_reg_self(tp, regs, this_cpu);
 257
 258         smp_fetch_global_regs();
 259
 260         for_each_cpu(cpu, mask) {
 261                 struct global_reg_snapshot *gp;
 262
 263                 if (cpu == exclude_cpu)
 264                         continue;
 265
 266                 gp = &global_cpu_snapshot[cpu].reg;
 267
 268                 __global_reg_poll(gp);
 269
 270                 tp = gp->thread;
 271                 printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
 272                        (cpu == this_cpu ? '*' : ' '), cpu,
 273                        gp->tstate, gp->tpc, gp->tnpc,
 274                        ((tp && tp->task) ? tp->task->comm : "NULL"),
 275                        ((tp && tp->task) ? tp->task->pid : -1));
 276
 277                 if (gp->tstate & TSTATE_PRIV) {
 278                         printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
 279                                (void *) gp->tpc,
 280                                (void *) gp->o7,
 281                                (void *) gp->i7,
 282                                (void *) gp->rpc);
 283                 } else {
 284                         printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
 285                                gp->tpc, gp->o7, gp->i7, gp->rpc);
 286                 }
 287
 288                 touch_nmi_watchdog();
 289         }
 290
 291         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 292
 293         spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
 294 }
 295
 296 #ifdef CONFIG_MAGIC_SYSRQ
 297
 298 static void sysrq_handle_globreg(u8 key)
 299 {
 300         trigger_all_cpu_backtrace();
 301 }
 302
 303 static const struct sysrq_key_op sparc_globalreg_op = {
 304         .handler        = sysrq_handle_globreg,
 305         .help_msg       = "global-regs(y)",
 306         .action_msg     = "Show Global CPU Regs",
 307 };
 308
 309 static void __global_pmu_self(int this_cpu)
 310 {
 311         struct global_pmu_snapshot *pp;
 312         int i, num;
 313
 314         if (!pcr_ops)
 315                 return;
 316
 317         pp = &global_cpu_snapshot[this_cpu].pmu;
 318
 319         num = 1;
 320         if (tlb_type == hypervisor &&
 321             sun4v_chip_type >= SUN4V_CHIP_NIAGARA4)
 322                 num = 4;
 323
 324         for (i = 0; i < num; i++) {
 325                 pp->pcr[i] = pcr_ops->read_pcr(i);
 326                 pp->pic[i] = pcr_ops->read_pic(i);
 327         }
 328 }
 329
 330 static void __global_pmu_poll(struct global_pmu_snapshot *pp)
 331 {
 332         int limit = 0;
 333
 334         while (!pp->pcr[0] && ++limit < 100) {
 335                 barrier();
 336                 udelay(1);
 337         }
 338 }
 339
 340 static void pmu_snapshot_all_cpus(void)
 341 {
 342         unsigned long flags;
 343         int this_cpu, cpu;
 344
 345         spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
 346
 347         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 348
 349         this_cpu = raw_smp_processor_id();
 350
 351         __global_pmu_self(this_cpu);
 352
 353         smp_fetch_global_pmu();
 354
 355         for_each_online_cpu(cpu) {
 356                 struct global_pmu_snapshot *pp = &global_cpu_snapshot[cpu].pmu;
 357
 358                 __global_pmu_poll(pp);
 359
 360                 printk("%c CPU[%3d]: PCR[%08lx:%08lx:%08lx:%08lx] PIC[%08lx:%08lx:%08lx:%08lx]\n",
 361                        (cpu == this_cpu ? '*' : ' '), cpu,
 362                        pp->pcr[0], pp->pcr[1], pp->pcr[2], pp->pcr[3],
 363                        pp->pic[0], pp->pic[1], pp->pic[2], pp->pic[3]);
 364
 365                 touch_nmi_watchdog();
 366         }
 367
 368         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 369
 370         spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
 371 }
 372
 373 static void sysrq_handle_globpmu(u8 key)
 374 {
 375         pmu_snapshot_all_cpus();
 376 }
 377
 378 static const struct sysrq_key_op sparc_globalpmu_op = {
 379         .handler        = sysrq_handle_globpmu,
 380         .help_msg       = "global-pmu(x)",
 381         .action_msg     = "Show Global PMU Regs",
 382 };
 383
 384 static int __init sparc_sysrq_init(void)
 385 {
 386         int ret = register_sysrq_key('y', &sparc_globalreg_op);
 387
 388         if (!ret)
 389                 ret = register_sysrq_key('x', &sparc_globalpmu_op);
 390         return ret;
 391 }
 392
 393 core_initcall(sparc_sysrq_init);
 394
 395 #endif
 396
 397 /* Free current thread data structures etc.. */
 398 void exit_thread(struct task_struct *tsk)
 399 {
 400         struct thread_info *t = task_thread_info(tsk);
 401
 402         if (t->utraps) {
 403                 if (t->utraps[0] < 2)
 404                         kfree (t->utraps);
 405                 else
 406                         t->utraps[0]--;
 407         }
 408 }
 409
 410 void flush_thread(void)
 411 {
 412         struct thread_info *t = current_thread_info();
 413         struct mm_struct *mm;
 414
 415         mm = t->task->mm;
 416         if (mm)
 417                 tsb_context_switch(mm);
 418
 419         set_thread_wsaved(0);
 420
 421         /* Clear FPU register state. */
 422         t->fpsaved[0] = 0;
 423 }
 424
 425 /* It's a bit more tricky when 64-bit tasks are involved... */
 426 static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
 427 {
 428         bool stack_64bit = test_thread_64bit_stack(psp);
 429         unsigned long fp, distance, rval;
 430
 431         if (stack_64bit) {
 432                 csp += STACK_BIAS;
 433                 psp += STACK_BIAS;
 434                 __get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
 435                 fp += STACK_BIAS;
 436                 if (test_thread_flag(TIF_32BIT))
 437                         fp &= 0xffffffff;
 438         } else
 439                 __get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
 440
 441         /* Now align the stack as this is mandatory in the Sparc ABI
 442          * due to how register windows work.  This hides the
 443          * restriction from thread libraries etc.
 444          */
 445         csp &= ~15UL;
 446
 447         distance = fp - psp;
 448         rval = (csp - distance);
 449         if (raw_copy_in_user((void __user *)rval, (void __user *)psp, distance))
 450                 rval = 0;
 451         else if (!stack_64bit) {
 452                 if (put_user(((u32)csp),
 453                              &(((struct reg_window32 __user *)rval)->ins[6])))
 454                         rval = 0;
 455         } else {
 456                 if (put_user(((u64)csp - STACK_BIAS),
 457                              &(((struct reg_window __user *)rval)->ins[6])))
 458                         rval = 0;
 459                 else
 460                         rval = rval - STACK_BIAS;
 461         }
 462
 463         return rval;
 464 }
 465
 466 /* Standard stuff. */
 467 static inline void shift_window_buffer(int first_win, int last_win,
 468                                        struct thread_info *t)
 469 {
 470         int i;
 471
 472         for (i = first_win; i < last_win; i++) {
 473                 t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
 474                 memcpy(&t->reg_window[i], &t->reg_window[i+1],
 475                        sizeof(struct reg_window));
 476         }
 477 }
 478
 479 void synchronize_user_stack(void)
 480 {
 481         struct thread_info *t = current_thread_info();
 482         unsigned long window;
 483
 484         flush_user_windows();
 485         if ((window = get_thread_wsaved()) != 0) {
 486                 window -= 1;
 487                 do {
 488                         struct reg_window *rwin = &t->reg_window[window];
 489                         int winsize = sizeof(struct reg_window);
 490                         unsigned long sp;
 491
 492                         sp = t->rwbuf_stkptrs[window];
 493
 494                         if (test_thread_64bit_stack(sp))
 495                                 sp += STACK_BIAS;
 496                         else
 497                                 winsize = sizeof(struct reg_window32);
 498
 499                         if (!copy_to_user((char __user *)sp, rwin, winsize)) {
 500                                 shift_window_buffer(window, get_thread_wsaved() - 1, t);
 501                                 set_thread_wsaved(get_thread_wsaved() - 1);
 502                         }
 503                 } while (window--);
 504         }
 505 }
 506
 507 static void stack_unaligned(unsigned long sp)
 508 {
 509         force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp);
 510 }
 511
 512 static const char uwfault32[] = KERN_INFO \
 513         "%s[%d]: bad register window fault: SP %08lx (orig_sp %08lx) TPC %08lx O7 %08lx\n";
 514 static const char uwfault64[] = KERN_INFO \
 515         "%s[%d]: bad register window fault: SP %016lx (orig_sp %016lx) TPC %08lx O7 %016lx\n";
 516
 517 void fault_in_user_windows(struct pt_regs *regs)
 518 {
 519         struct thread_info *t = current_thread_info();
 520         unsigned long window;
 521
 522         flush_user_windows();
 523         window = get_thread_wsaved();
 524
 525         if (likely(window != 0)) {
 526                 window -= 1;
 527                 do {
 528                         struct reg_window *rwin = &t->reg_window[window];
 529                         int winsize = sizeof(struct reg_window);
 530                         unsigned long sp, orig_sp;
 531
 532                         orig_sp = sp = t->rwbuf_stkptrs[window];
 533
 534                         if (test_thread_64bit_stack(sp))
 535                                 sp += STACK_BIAS;
 536                         else
 537                                 winsize = sizeof(struct reg_window32);
 538
 539                         if (unlikely(sp & 0x7UL))
 540                                 stack_unaligned(sp);
 541
 542                         if (unlikely(copy_to_user((char __user *)sp,
 543                                                   rwin, winsize))) {
 544                                 if (show_unhandled_signals)
 545                                         printk_ratelimited(is_compat_task() ?
 546                                                            uwfault32 : uwfault64,
 547                                                            current->comm, current->pid,
 548                                                            sp, orig_sp,
 549                                                            regs->tpc,
 550                                                            regs->u_regs[UREG_I7]);
 551                                 goto barf;
 552                         }
 553                 } while (window--);
 554         }
 555         set_thread_wsaved(0);
 556         return;
 557
 558 barf:
 559         set_thread_wsaved(window + 1);
 560         force_sig(SIGSEGV);
 561 }
 562
 563 /* Copy a Sparc thread.  The fork() return value conventions
 564  * under SunOS are nothing short of bletcherous:
 565  * Parent -->  %o0 == childs  pid, %o1 == 0
 566  * Child  -->  %o0 == parents pid, %o1 == 1
 567  */
 568 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 569 {
 570         unsigned long clone_flags = args->flags;
 571         unsigned long sp = args->stack;
 572         unsigned long tls = args->tls;
 573         struct thread_info *t = task_thread_info(p);
 574         struct pt_regs *regs = current_pt_regs();
 575         struct sparc_stackf *parent_sf;
 576         unsigned long child_stack_sz;
 577         char *child_trap_frame;
 578
 579         /* Calculate offset to stack_frame & pt_regs */
 580         child_stack_sz = (STACKFRAME_SZ + TRACEREG_SZ);
 581         child_trap_frame = (task_stack_page(p) +
 582                             (THREAD_SIZE - child_stack_sz));
 583
 584         t->new_child = 1;
 585         t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
 586         t->kregs = (struct pt_regs *) (child_trap_frame +
 587                                        sizeof(struct sparc_stackf));
 588         t->fpsaved[0] = 0;
 589
 590         if (unlikely(args->fn)) {
 591                 memset(child_trap_frame, 0, child_stack_sz);
 592                 __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
 593                         (current_pt_regs()->tstate + 1) & TSTATE_CWP;
 594                 t->kregs->u_regs[UREG_G1] = (unsigned long) args->fn;
 595                 t->kregs->u_regs[UREG_G2] = (unsigned long) args->fn_arg;
 596                 return 0;
 597         }
 598
 599         parent_sf = ((struct sparc_stackf *) regs) - 1;
 600         memcpy(child_trap_frame, parent_sf, child_stack_sz);
 601         if (t->flags & _TIF_32BIT) {
 602                 sp &= 0x00000000ffffffffUL;
 603                 regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
 604         }
 605         t->kregs->u_regs[UREG_FP] = sp;
 606         __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
 607                 (regs->tstate + 1) & TSTATE_CWP;
 608         if (sp != regs->u_regs[UREG_FP]) {
 609                 unsigned long csp;
 610
 611                 csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
 612                 if (!csp)
 613                         return -EFAULT;
 614                 t->kregs->u_regs[UREG_FP] = csp;
 615         }
 616         if (t->utraps)
 617                 t->utraps[0]++;
 618
 619         /* Set the return value for the child. */
 620         t->kregs->u_regs[UREG_I0] = current->pid;
 621         t->kregs->u_regs[UREG_I1] = 1;
 622
 623         /* Set the second return value for the parent. */
 624         regs->u_regs[UREG_I1] = 0;
 625
 626         if (clone_flags & CLONE_SETTLS)
 627                 t->kregs->u_regs[UREG_G7] = tls;
 628
 629         return 0;
 630 }
 631
 632 /* TIF_MCDPER in thread info flags for current task is updated lazily upon
 633  * a context switch. Update this flag in current task's thread flags
 634  * before dup so the dup'd task will inherit the current TIF_MCDPER flag.
 635  */
 636 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 637 {
 638         if (adi_capable()) {
 639                 register unsigned long tmp_mcdper;
 640
 641                 __asm__ __volatile__(
 642                         ".word 0x83438000\n\t"  /* rd  %mcdper, %g1 */
 643                         "mov %%g1, %0\n\t"
 644                         : "=r" (tmp_mcdper)
 645                         :
 646                         : "g1");
 647                 if (tmp_mcdper)
 648                         set_thread_flag(TIF_MCDPER);
 649                 else
 650                         clear_thread_flag(TIF_MCDPER);
 651         }
 652
 653         *dst = *src;
 654         return 0;
 655 }
 656
 657 unsigned long __get_wchan(struct task_struct *task)
 658 {
 659         unsigned long pc, fp, bias = 0;
 660         struct thread_info *tp;
 661         struct reg_window *rw;
 662         unsigned long ret = 0;
 663         int count = 0;
 664
 665         tp = task_thread_info(task);
 666         bias = STACK_BIAS;
 667         fp = task_thread_info(task)->ksp + bias;
 668
 669         do {
 670                 if (!kstack_valid(tp, fp))
 671                         break;
 672                 rw = (struct reg_window *) fp;
 673                 pc = rw->ins[7];
 674                 if (!in_sched_functions(pc)) {
 675                         ret = pc;
 676                         goto out;
 677                 }
 678                 fp = rw->ins[6] + bias;
 679         } while (++count < 16);
 680
 681 out:
 682         return ret;
 683 }