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                 raw_local_irq_enable();
  63         } else {
  64                 unsigned long pstate;
  65
  66                 raw_local_irq_enable();
  67
  68                 /* The sun4v sleeping code requires that we have PSTATE.IE cleared over
  69                  * the cpu sleep hypervisor call.
  70                  */
  71                 __asm__ __volatile__(
  72                         "rdpr %%pstate, %0\n\t"
  73                         "andn %0, %1, %0\n\t"
  74                         "wrpr %0, %%g0, %%pstate"
  75                         : "=&r" (pstate)
  76                         : "i" (PSTATE_IE));
  77
  78                 if (!need_resched() && !cpu_is_offline(smp_processor_id())) {
  79                         sun4v_cpu_yield();
  80                         /* If resumed by cpu_poke then we need to explicitly
  81                          * call scheduler_ipi().
  82                          */
  83                         scheduler_poke();
  84                 }
  85
  86                 /* Re-enable interrupts. */
  87                 __asm__ __volatile__(
  88                         "rdpr %%pstate, %0\n\t"
  89                         "or %0, %1, %0\n\t"
  90                         "wrpr %0, %%g0, %%pstate"
  91                         : "=&r" (pstate)
  92                         : "i" (PSTATE_IE));
  93         }
  94 }
  95
  96 #ifdef CONFIG_HOTPLUG_CPU
  97 void arch_cpu_idle_dead(void)
  98 {
  99         sched_preempt_enable_no_resched();
 100         cpu_play_dead();
 101 }
 102 #endif
 103
 104 #ifdef CONFIG_COMPAT
 105 static void show_regwindow32(struct pt_regs *regs)
 106 {
 107         struct reg_window32 __user *rw;
 108         struct reg_window32 r_w;
 109         mm_segment_t old_fs;
 110
 111         __asm__ __volatile__ ("flushw");
 112         rw = compat_ptr((unsigned int)regs->u_regs[14]);
 113         old_fs = get_fs();
 114         set_fs (USER_DS);
 115         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 116                 set_fs (old_fs);
 117                 return;
 118         }
 119
 120         set_fs (old_fs);
 121         printk("l0: %08x l1: %08x l2: %08x l3: %08x "
 122                "l4: %08x l5: %08x l6: %08x l7: %08x\n",
 123                r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
 124                r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
 125         printk("i0: %08x i1: %08x i2: %08x i3: %08x "
 126                "i4: %08x i5: %08x i6: %08x i7: %08x\n",
 127                r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
 128                r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
 129 }
 130 #else
 131 #define show_regwindow32(regs)  do { } while (0)
 132 #endif
 133
 134 static void show_regwindow(struct pt_regs *regs)
 135 {
 136         struct reg_window __user *rw;
 137         struct reg_window *rwk;
 138         struct reg_window r_w;
 139         mm_segment_t old_fs;
 140
 141         if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
 142                 __asm__ __volatile__ ("flushw");
 143                 rw = (struct reg_window __user *)
 144                         (regs->u_regs[14] + STACK_BIAS);
 145                 rwk = (struct reg_window *)
 146                         (regs->u_regs[14] + STACK_BIAS);
 147                 if (!(regs->tstate & TSTATE_PRIV)) {
 148                         old_fs = get_fs();
 149                         set_fs (USER_DS);
 150                         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 151                                 set_fs (old_fs);
 152                                 return;
 153                         }
 154                         rwk = &r_w;
 155                         set_fs (old_fs);
 156                 }
 157         } else {
 158                 show_regwindow32(regs);
 159                 return;
 160         }
 161         printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
 162                rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
 163         printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
 164                rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
 165         printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
 166                rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
 167         printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
 168                rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
 169         if (regs->tstate & TSTATE_PRIV)
 170                 printk("I7: <%pS>\n", (void *) rwk->ins[7]);
 171 }
 172
 173 void show_regs(struct pt_regs *regs)
 174 {
 175         show_regs_print_info(KERN_DEFAULT);
 176
 177         printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
 178                regs->tpc, regs->tnpc, regs->y, print_tainted());
 179         printk("TPC: <%pS>\n", (void *) regs->tpc);
 180         printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
 181                regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
 182                regs->u_regs[3]);
 183         printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
 184                regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
 185                regs->u_regs[7]);
 186         printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
 187                regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
 188                regs->u_regs[11]);
 189         printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
 190                regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
 191                regs->u_regs[15]);
 192         printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
 193         show_regwindow(regs);
 194         show_stack(current, (unsigned long *)regs->u_regs[UREG_FP], KERN_DEFAULT);
 195 }
 196
 197 union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
 198 static DEFINE_SPINLOCK(global_cpu_snapshot_lock);
 199
 200 static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
 201                               int this_cpu)
 202 {
 203         struct global_reg_snapshot *rp;
 204
 205         flushw_all();
 206
 207         rp = &global_cpu_snapshot[this_cpu].reg;
 208
 209         rp->tstate = regs->tstate;
 210         rp->tpc = regs->tpc;
 211         rp->tnpc = regs->tnpc;
 212         rp->o7 = regs->u_regs[UREG_I7];
 213
 214         if (regs->tstate & TSTATE_PRIV) {
 215                 struct reg_window *rw;
 216
 217                 rw = (struct reg_window *)
 218                         (regs->u_regs[UREG_FP] + STACK_BIAS);
 219                 if (kstack_valid(tp, (unsigned long) rw)) {
 220                         rp->i7 = rw->ins[7];
 221                         rw = (struct reg_window *)
 222                                 (rw->ins[6] + STACK_BIAS);
 223                         if (kstack_valid(tp, (unsigned long) rw))
 224                                 rp->rpc = rw->ins[7];
 225                 }
 226         } else {
 227                 rp->i7 = 0;
 228                 rp->rpc = 0;
 229         }
 230         rp->thread = tp;
 231 }
 232
 233 /* In order to avoid hangs we do not try to synchronize with the
 234  * global register dump client cpus.  The last store they make is to
 235  * the thread pointer, so do a short poll waiting for that to become
 236  * non-NULL.
 237  */
 238 static void __global_reg_poll(struct global_reg_snapshot *gp)
 239 {
 240         int limit = 0;
 241
 242         while (!gp->thread && ++limit < 100) {
 243                 barrier();
 244                 udelay(1);
 245         }
 246 }
 247
 248 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
 249 {
 250         struct thread_info *tp = current_thread_info();
 251         struct pt_regs *regs = get_irq_regs();
 252         unsigned long flags;
 253         int this_cpu, cpu;
 254
 255         if (!regs)
 256                 regs = tp->kregs;
 257
 258         spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
 259
 260         this_cpu = raw_smp_processor_id();
 261
 262         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 263
 264         if (cpumask_test_cpu(this_cpu, mask) && !exclude_self)
 265                 __global_reg_self(tp, regs, this_cpu);
 266
 267         smp_fetch_global_regs();
 268
 269         for_each_cpu(cpu, mask) {
 270                 struct global_reg_snapshot *gp;
 271
 272                 if (exclude_self && cpu == this_cpu)
 273                         continue;
 274
 275                 gp = &global_cpu_snapshot[cpu].reg;
 276
 277                 __global_reg_poll(gp);
 278
 279                 tp = gp->thread;
 280                 printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
 281                        (cpu == this_cpu ? '*' : ' '), cpu,
 282                        gp->tstate, gp->tpc, gp->tnpc,
 283                        ((tp && tp->task) ? tp->task->comm : "NULL"),
 284                        ((tp && tp->task) ? tp->task->pid : -1));
 285
 286                 if (gp->tstate & TSTATE_PRIV) {
 287                         printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
 288                                (void *) gp->tpc,
 289                                (void *) gp->o7,
 290                                (void *) gp->i7,
 291                                (void *) gp->rpc);
 292                 } else {
 293                         printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
 294                                gp->tpc, gp->o7, gp->i7, gp->rpc);
 295                 }
 296
 297                 touch_nmi_watchdog();
 298         }
 299
 300         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 301
 302         spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
 303 }
 304
 305 #ifdef CONFIG_MAGIC_SYSRQ
 306
 307 static void sysrq_handle_globreg(int key)
 308 {
 309         trigger_all_cpu_backtrace();
 310 }
 311
 312 static const struct sysrq_key_op sparc_globalreg_op = {
 313         .handler        = sysrq_handle_globreg,
 314         .help_msg       = "global-regs(y)",
 315         .action_msg     = "Show Global CPU Regs",
 316 };
 317
 318 static void __global_pmu_self(int this_cpu)
 319 {
 320         struct global_pmu_snapshot *pp;
 321         int i, num;
 322
 323         if (!pcr_ops)
 324                 return;
 325
 326         pp = &global_cpu_snapshot[this_cpu].pmu;
 327
 328         num = 1;
 329         if (tlb_type == hypervisor &&
 330             sun4v_chip_type >= SUN4V_CHIP_NIAGARA4)
 331                 num = 4;
 332
 333         for (i = 0; i < num; i++) {
 334                 pp->pcr[i] = pcr_ops->read_pcr(i);
 335                 pp->pic[i] = pcr_ops->read_pic(i);
 336         }
 337 }
 338
 339 static void __global_pmu_poll(struct global_pmu_snapshot *pp)
 340 {
 341         int limit = 0;
 342
 343         while (!pp->pcr[0] && ++limit < 100) {
 344                 barrier();
 345                 udelay(1);
 346         }
 347 }
 348
 349 static void pmu_snapshot_all_cpus(void)
 350 {
 351         unsigned long flags;
 352         int this_cpu, cpu;
 353
 354         spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
 355
 356         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 357
 358         this_cpu = raw_smp_processor_id();
 359
 360         __global_pmu_self(this_cpu);
 361
 362         smp_fetch_global_pmu();
 363
 364         for_each_online_cpu(cpu) {
 365                 struct global_pmu_snapshot *pp = &global_cpu_snapshot[cpu].pmu;
 366
 367                 __global_pmu_poll(pp);
 368
 369                 printk("%c CPU[%3d]: PCR[%08lx:%08lx:%08lx:%08lx] PIC[%08lx:%08lx:%08lx:%08lx]\n",
 370                        (cpu == this_cpu ? '*' : ' '), cpu,
 371                        pp->pcr[0], pp->pcr[1], pp->pcr[2], pp->pcr[3],
 372                        pp->pic[0], pp->pic[1], pp->pic[2], pp->pic[3]);
 373
 374                 touch_nmi_watchdog();
 375         }
 376
 377         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 378
 379         spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
 380 }
 381
 382 static void sysrq_handle_globpmu(int key)
 383 {
 384         pmu_snapshot_all_cpus();
 385 }
 386
 387 static const struct sysrq_key_op sparc_globalpmu_op = {
 388         .handler        = sysrq_handle_globpmu,
 389         .help_msg       = "global-pmu(x)",
 390         .action_msg     = "Show Global PMU Regs",
 391 };
 392
 393 static int __init sparc_sysrq_init(void)
 394 {
 395         int ret = register_sysrq_key('y', &sparc_globalreg_op);
 396
 397         if (!ret)
 398                 ret = register_sysrq_key('x', &sparc_globalpmu_op);
 399         return ret;
 400 }
 401
 402 core_initcall(sparc_sysrq_init);
 403
 404 #endif
 405
 406 /* Free current thread data structures etc.. */
 407 void exit_thread(struct task_struct *tsk)
 408 {
 409         struct thread_info *t = task_thread_info(tsk);
 410
 411         if (t->utraps) {
 412                 if (t->utraps[0] < 2)
 413                         kfree (t->utraps);
 414                 else
 415                         t->utraps[0]--;
 416         }
 417 }
 418
 419 void flush_thread(void)
 420 {
 421         struct thread_info *t = current_thread_info();
 422         struct mm_struct *mm;
 423
 424         mm = t->task->mm;
 425         if (mm)
 426                 tsb_context_switch(mm);
 427
 428         set_thread_wsaved(0);
 429
 430         /* Clear FPU register state. */
 431         t->fpsaved[0] = 0;
 432 }
 433
 434 /* It's a bit more tricky when 64-bit tasks are involved... */
 435 static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
 436 {
 437         bool stack_64bit = test_thread_64bit_stack(psp);
 438         unsigned long fp, distance, rval;
 439
 440         if (stack_64bit) {
 441                 csp += STACK_BIAS;
 442                 psp += STACK_BIAS;
 443                 __get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
 444                 fp += STACK_BIAS;
 445                 if (test_thread_flag(TIF_32BIT))
 446                         fp &= 0xffffffff;
 447         } else
 448                 __get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
 449
 450         /* Now align the stack as this is mandatory in the Sparc ABI
 451          * due to how register windows work.  This hides the
 452          * restriction from thread libraries etc.
 453          */
 454         csp &= ~15UL;
 455
 456         distance = fp - psp;
 457         rval = (csp - distance);
 458         if (copy_in_user((void __user *) rval, (void __user *) psp, distance))
 459                 rval = 0;
 460         else if (!stack_64bit) {
 461                 if (put_user(((u32)csp),
 462                              &(((struct reg_window32 __user *)rval)->ins[6])))
 463                         rval = 0;
 464         } else {
 465                 if (put_user(((u64)csp - STACK_BIAS),
 466                              &(((struct reg_window __user *)rval)->ins[6])))
 467                         rval = 0;
 468                 else
 469                         rval = rval - STACK_BIAS;
 470         }
 471
 472         return rval;
 473 }
 474
 475 /* Standard stuff. */
 476 static inline void shift_window_buffer(int first_win, int last_win,
 477                                        struct thread_info *t)
 478 {
 479         int i;
 480
 481         for (i = first_win; i < last_win; i++) {
 482                 t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
 483                 memcpy(&t->reg_window[i], &t->reg_window[i+1],
 484                        sizeof(struct reg_window));
 485         }
 486 }
 487
 488 void synchronize_user_stack(void)
 489 {
 490         struct thread_info *t = current_thread_info();
 491         unsigned long window;
 492
 493         flush_user_windows();
 494         if ((window = get_thread_wsaved()) != 0) {
 495                 window -= 1;
 496                 do {
 497                         struct reg_window *rwin = &t->reg_window[window];
 498                         int winsize = sizeof(struct reg_window);
 499                         unsigned long sp;
 500
 501                         sp = t->rwbuf_stkptrs[window];
 502
 503                         if (test_thread_64bit_stack(sp))
 504                                 sp += STACK_BIAS;
 505                         else
 506                                 winsize = sizeof(struct reg_window32);
 507
 508                         if (!copy_to_user((char __user *)sp, rwin, winsize)) {
 509                                 shift_window_buffer(window, get_thread_wsaved() - 1, t);
 510                                 set_thread_wsaved(get_thread_wsaved() - 1);
 511                         }
 512                 } while (window--);
 513         }
 514 }
 515
 516 static void stack_unaligned(unsigned long sp)
 517 {
 518         force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp);
 519 }
 520
 521 static const char uwfault32[] = KERN_INFO \
 522         "%s[%d]: bad register window fault: SP %08lx (orig_sp %08lx) TPC %08lx O7 %08lx\n";
 523 static const char uwfault64[] = KERN_INFO \
 524         "%s[%d]: bad register window fault: SP %016lx (orig_sp %016lx) TPC %08lx O7 %016lx\n";
 525
 526 void fault_in_user_windows(struct pt_regs *regs)
 527 {
 528         struct thread_info *t = current_thread_info();
 529         unsigned long window;
 530
 531         flush_user_windows();
 532         window = get_thread_wsaved();
 533
 534         if (likely(window != 0)) {
 535                 window -= 1;
 536                 do {
 537                         struct reg_window *rwin = &t->reg_window[window];
 538                         int winsize = sizeof(struct reg_window);
 539                         unsigned long sp, orig_sp;
 540
 541                         orig_sp = sp = t->rwbuf_stkptrs[window];
 542
 543                         if (test_thread_64bit_stack(sp))
 544                                 sp += STACK_BIAS;
 545                         else
 546                                 winsize = sizeof(struct reg_window32);
 547
 548                         if (unlikely(sp & 0x7UL))
 549                                 stack_unaligned(sp);
 550
 551                         if (unlikely(copy_to_user((char __user *)sp,
 552                                                   rwin, winsize))) {
 553                                 if (show_unhandled_signals)
 554                                         printk_ratelimited(is_compat_task() ?
 555                                                            uwfault32 : uwfault64,
 556                                                            current->comm, current->pid,
 557                                                            sp, orig_sp,
 558                                                            regs->tpc,
 559                                                            regs->u_regs[UREG_I7]);
 560                                 goto barf;
 561                         }
 562                 } while (window--);
 563         }
 564         set_thread_wsaved(0);
 565         return;
 566
 567 barf:
 568         set_thread_wsaved(window + 1);
 569         force_sig(SIGSEGV);
 570 }
 571
 572 /* Copy a Sparc thread.  The fork() return value conventions
 573  * under SunOS are nothing short of bletcherous:
 574  * Parent -->  %o0 == childs  pid, %o1 == 0
 575  * Child  -->  %o0 == parents pid, %o1 == 1
 576  */
 577 int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
 578                 struct task_struct *p, unsigned long tls)
 579 {
 580         struct thread_info *t = task_thread_info(p);
 581         struct pt_regs *regs = current_pt_regs();
 582         struct sparc_stackf *parent_sf;
 583         unsigned long child_stack_sz;
 584         char *child_trap_frame;
 585
 586         /* Calculate offset to stack_frame & pt_regs */
 587         child_stack_sz = (STACKFRAME_SZ + TRACEREG_SZ);
 588         child_trap_frame = (task_stack_page(p) +
 589                             (THREAD_SIZE - child_stack_sz));
 590
 591         t->new_child = 1;
 592         t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
 593         t->kregs = (struct pt_regs *) (child_trap_frame +
 594                                        sizeof(struct sparc_stackf));
 595         t->fpsaved[0] = 0;
 596
 597         if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
 598                 memset(child_trap_frame, 0, child_stack_sz);
 599                 __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
 600                         (current_pt_regs()->tstate + 1) & TSTATE_CWP;
 601                 t->current_ds = ASI_P;
 602                 t->kregs->u_regs[UREG_G1] = sp; /* function */
 603                 t->kregs->u_regs[UREG_G2] = arg;
 604                 return 0;
 605         }
 606
 607         parent_sf = ((struct sparc_stackf *) regs) - 1;
 608         memcpy(child_trap_frame, parent_sf, child_stack_sz);
 609         if (t->flags & _TIF_32BIT) {
 610                 sp &= 0x00000000ffffffffUL;
 611                 regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
 612         }
 613         t->kregs->u_regs[UREG_FP] = sp;
 614         __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
 615                 (regs->tstate + 1) & TSTATE_CWP;
 616         t->current_ds = ASI_AIUS;
 617         if (sp != regs->u_regs[UREG_FP]) {
 618                 unsigned long csp;
 619
 620                 csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
 621                 if (!csp)
 622                         return -EFAULT;
 623                 t->kregs->u_regs[UREG_FP] = csp;
 624         }
 625         if (t->utraps)
 626                 t->utraps[0]++;
 627
 628         /* Set the return value for the child. */
 629         t->kregs->u_regs[UREG_I0] = current->pid;
 630         t->kregs->u_regs[UREG_I1] = 1;
 631
 632         /* Set the second return value for the parent. */
 633         regs->u_regs[UREG_I1] = 0;
 634
 635         if (clone_flags & CLONE_SETTLS)
 636                 t->kregs->u_regs[UREG_G7] = tls;
 637
 638         return 0;
 639 }
 640
 641 /* TIF_MCDPER in thread info flags for current task is updated lazily upon
 642  * a context switch. Update this flag in current task's thread flags
 643  * before dup so the dup'd task will inherit the current TIF_MCDPER flag.
 644  */
 645 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 646 {
 647         if (adi_capable()) {
 648                 register unsigned long tmp_mcdper;
 649
 650                 __asm__ __volatile__(
 651                         ".word 0x83438000\n\t"  /* rd  %mcdper, %g1 */
 652                         "mov %%g1, %0\n\t"
 653                         : "=r" (tmp_mcdper)
 654                         :
 655                         : "g1");
 656                 if (tmp_mcdper)
 657                         set_thread_flag(TIF_MCDPER);
 658                 else
 659                         clear_thread_flag(TIF_MCDPER);
 660         }
 661
 662         *dst = *src;
 663         return 0;
 664 }
 665
 666 unsigned long get_wchan(struct task_struct *task)
 667 {
 668         unsigned long pc, fp, bias = 0;
 669         struct thread_info *tp;
 670         struct reg_window *rw;
 671         unsigned long ret = 0;
 672         int count = 0;
 673
 674         if (!task || task == current || task_is_running(task))
 675                 goto out;
 676
 677         tp = task_thread_info(task);
 678         bias = STACK_BIAS;
 679         fp = task_thread_info(task)->ksp + bias;
 680
 681         do {
 682                 if (!kstack_valid(tp, fp))
 683                         break;
 684                 rw = (struct reg_window *) fp;
 685                 pc = rw->ins[7];
 686                 if (!in_sched_functions(pc)) {
 687                         ret = pc;
 688                         goto out;
 689                 }
 690                 fp = rw->ins[6] + bias;
 691         } while (++count < 16);
 692
 693 out:
 694         return ret;
 695 }