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
  13 #include <stdarg.h>
  14
  15 #include <linux/errno.h>
  16 #include <linux/export.h>
  17 #include <linux/sched.h>
  18 #include <linux/sched/debug.h>
  19 #include <linux/sched/task.h>
  20 #include <linux/sched/task_stack.h>
  21 #include <linux/kernel.h>
  22 #include <linux/mm.h>
  23 #include <linux/fs.h>
  24 #include <linux/smp.h>
  25 #include <linux/stddef.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/slab.h>
  28 #include <linux/user.h>
  29 #include <linux/delay.h>
  30 #include <linux/compat.h>
  31 #include <linux/tick.h>
  32 #include <linux/init.h>
  33 #include <linux/cpu.h>
  34 #include <linux/perf_event.h>
  35 #include <linux/elfcore.h>
  36 #include <linux/sysrq.h>
  37 #include <linux/nmi.h>
  38 #include <linux/context_tracking.h>
  39 #include <linux/signal.h>
  40
  41 #include <linux/uaccess.h>
  42 #include <asm/page.h>
  43 #include <asm/pgalloc.h>
  44 #include <asm/processor.h>
  45 #include <asm/pstate.h>
  46 #include <asm/elf.h>
  47 #include <asm/fpumacro.h>
  48 #include <asm/head.h>
  49 #include <asm/cpudata.h>
  50 #include <asm/mmu_context.h>
  51 #include <asm/unistd.h>
  52 #include <asm/hypervisor.h>
  53 #include <asm/syscalls.h>
  54 #include <asm/irq_regs.h>
  55 #include <asm/smp.h>
  56 #include <asm/pcr.h>
  57
  58 #include "kstack.h"
  59
  60 /* Idle loop support on sparc64. */
  61 void arch_cpu_idle(void)
  62 {
  63         if (tlb_type != hypervisor) {
  64                 touch_nmi_watchdog();
  65                 raw_local_irq_enable();
  66         } else {
  67                 unsigned long pstate;
  68
  69                 raw_local_irq_enable();
  70
  71                 /* The sun4v sleeping code requires that we have PSTATE.IE cleared over
  72                  * the cpu sleep hypervisor call.
  73                  */
  74                 __asm__ __volatile__(
  75                         "rdpr %%pstate, %0\n\t"
  76                         "andn %0, %1, %0\n\t"
  77                         "wrpr %0, %%g0, %%pstate"
  78                         : "=&r" (pstate)
  79                         : "i" (PSTATE_IE));
  80
  81                 if (!need_resched() && !cpu_is_offline(smp_processor_id())) {
  82                         sun4v_cpu_yield();
  83                         /* If resumed by cpu_poke then we need to explicitly
  84                          * call scheduler_ipi().
  85                          */
  86                         scheduler_poke();
  87                 }
  88
  89                 /* Re-enable interrupts. */
  90                 __asm__ __volatile__(
  91                         "rdpr %%pstate, %0\n\t"
  92                         "or %0, %1, %0\n\t"
  93                         "wrpr %0, %%g0, %%pstate"
  94                         : "=&r" (pstate)
  95                         : "i" (PSTATE_IE));
  96         }
  97 }
  98
  99 #ifdef CONFIG_HOTPLUG_CPU
 100 void arch_cpu_idle_dead(void)
 101 {
 102         sched_preempt_enable_no_resched();
 103         cpu_play_dead();
 104 }
 105 #endif
 106
 107 #ifdef CONFIG_COMPAT
 108 static void show_regwindow32(struct pt_regs *regs)
 109 {
 110         struct reg_window32 __user *rw;
 111         struct reg_window32 r_w;
 112         mm_segment_t old_fs;
 113
 114         __asm__ __volatile__ ("flushw");
 115         rw = compat_ptr((unsigned int)regs->u_regs[14]);
 116         old_fs = get_fs();
 117         set_fs (USER_DS);
 118         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 119                 set_fs (old_fs);
 120                 return;
 121         }
 122
 123         set_fs (old_fs);
 124         printk("l0: %08x l1: %08x l2: %08x l3: %08x "
 125                "l4: %08x l5: %08x l6: %08x l7: %08x\n",
 126                r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
 127                r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
 128         printk("i0: %08x i1: %08x i2: %08x i3: %08x "
 129                "i4: %08x i5: %08x i6: %08x i7: %08x\n",
 130                r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
 131                r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
 132 }
 133 #else
 134 #define show_regwindow32(regs)  do { } while (0)
 135 #endif
 136
 137 static void show_regwindow(struct pt_regs *regs)
 138 {
 139         struct reg_window __user *rw;
 140         struct reg_window *rwk;
 141         struct reg_window r_w;
 142         mm_segment_t old_fs;
 143
 144         if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
 145                 __asm__ __volatile__ ("flushw");
 146                 rw = (struct reg_window __user *)
 147                         (regs->u_regs[14] + STACK_BIAS);
 148                 rwk = (struct reg_window *)
 149                         (regs->u_regs[14] + STACK_BIAS);
 150                 if (!(regs->tstate & TSTATE_PRIV)) {
 151                         old_fs = get_fs();
 152                         set_fs (USER_DS);
 153                         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 154                                 set_fs (old_fs);
 155                                 return;
 156                         }
 157                         rwk = &r_w;
 158                         set_fs (old_fs);
 159                 }
 160         } else {
 161                 show_regwindow32(regs);
 162                 return;
 163         }
 164         printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
 165                rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
 166         printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
 167                rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
 168         printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
 169                rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
 170         printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
 171                rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
 172         if (regs->tstate & TSTATE_PRIV)
 173                 printk("I7: <%pS>\n", (void *) rwk->ins[7]);
 174 }
 175
 176 void show_regs(struct pt_regs *regs)
 177 {
 178         show_regs_print_info(KERN_DEFAULT);
 179
 180         printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
 181                regs->tpc, regs->tnpc, regs->y, print_tainted());
 182         printk("TPC: <%pS>\n", (void *) regs->tpc);
 183         printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
 184                regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
 185                regs->u_regs[3]);
 186         printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
 187                regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
 188                regs->u_regs[7]);
 189         printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
 190                regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
 191                regs->u_regs[11]);
 192         printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
 193                regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
 194                regs->u_regs[15]);
 195         printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
 196         show_regwindow(regs);
 197         show_stack(current, (unsigned long *)regs->u_regs[UREG_FP], KERN_DEFAULT);
 198 }
 199
 200 union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
 201 static DEFINE_SPINLOCK(global_cpu_snapshot_lock);
 202
 203 static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
 204                               int this_cpu)
 205 {
 206         struct global_reg_snapshot *rp;
 207
 208         flushw_all();
 209
 210         rp = &global_cpu_snapshot[this_cpu].reg;
 211
 212         rp->tstate = regs->tstate;
 213         rp->tpc = regs->tpc;
 214         rp->tnpc = regs->tnpc;
 215         rp->o7 = regs->u_regs[UREG_I7];
 216
 217         if (regs->tstate & TSTATE_PRIV) {
 218                 struct reg_window *rw;
 219
 220                 rw = (struct reg_window *)
 221                         (regs->u_regs[UREG_FP] + STACK_BIAS);
 222                 if (kstack_valid(tp, (unsigned long) rw)) {
 223                         rp->i7 = rw->ins[7];
 224                         rw = (struct reg_window *)
 225                                 (rw->ins[6] + STACK_BIAS);
 226                         if (kstack_valid(tp, (unsigned long) rw))
 227                                 rp->rpc = rw->ins[7];
 228                 }
 229         } else {
 230                 rp->i7 = 0;
 231                 rp->rpc = 0;
 232         }
 233         rp->thread = tp;
 234 }
 235
 236 /* In order to avoid hangs we do not try to synchronize with the
 237  * global register dump client cpus.  The last store they make is to
 238  * the thread pointer, so do a short poll waiting for that to become
 239  * non-NULL.
 240  */
 241 static void __global_reg_poll(struct global_reg_snapshot *gp)
 242 {
 243         int limit = 0;
 244
 245         while (!gp->thread && ++limit < 100) {
 246                 barrier();
 247                 udelay(1);
 248         }
 249 }
 250
 251 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
 252 {
 253         struct thread_info *tp = current_thread_info();
 254         struct pt_regs *regs = get_irq_regs();
 255         unsigned long flags;
 256         int this_cpu, cpu;
 257
 258         if (!regs)
 259                 regs = tp->kregs;
 260
 261         spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
 262
 263         this_cpu = raw_smp_processor_id();
 264
 265         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 266
 267         if (cpumask_test_cpu(this_cpu, mask) && !exclude_self)
 268                 __global_reg_self(tp, regs, this_cpu);
 269
 270         smp_fetch_global_regs();
 271
 272         for_each_cpu(cpu, mask) {
 273                 struct global_reg_snapshot *gp;
 274
 275                 if (exclude_self && cpu == this_cpu)
 276                         continue;
 277
 278                 gp = &global_cpu_snapshot[cpu].reg;
 279
 280                 __global_reg_poll(gp);
 281
 282                 tp = gp->thread;
 283                 printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
 284                        (cpu == this_cpu ? '*' : ' '), cpu,
 285                        gp->tstate, gp->tpc, gp->tnpc,
 286                        ((tp && tp->task) ? tp->task->comm : "NULL"),
 287                        ((tp && tp->task) ? tp->task->pid : -1));
 288
 289                 if (gp->tstate & TSTATE_PRIV) {
 290                         printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
 291                                (void *) gp->tpc,
 292                                (void *) gp->o7,
 293                                (void *) gp->i7,
 294                                (void *) gp->rpc);
 295                 } else {
 296                         printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
 297                                gp->tpc, gp->o7, gp->i7, gp->rpc);
 298                 }
 299
 300                 touch_nmi_watchdog();
 301         }
 302
 303         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 304
 305         spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
 306 }
 307
 308 #ifdef CONFIG_MAGIC_SYSRQ
 309
 310 static void sysrq_handle_globreg(int key)
 311 {
 312         trigger_all_cpu_backtrace();
 313 }
 314
 315 static const struct sysrq_key_op sparc_globalreg_op = {
 316         .handler        = sysrq_handle_globreg,
 317         .help_msg       = "global-regs(y)",
 318         .action_msg     = "Show Global CPU Regs",
 319 };
 320
 321 static void __global_pmu_self(int this_cpu)
 322 {
 323         struct global_pmu_snapshot *pp;
 324         int i, num;
 325
 326         if (!pcr_ops)
 327                 return;
 328
 329         pp = &global_cpu_snapshot[this_cpu].pmu;
 330
 331         num = 1;
 332         if (tlb_type == hypervisor &&
 333             sun4v_chip_type >= SUN4V_CHIP_NIAGARA4)
 334                 num = 4;
 335
 336         for (i = 0; i < num; i++) {
 337                 pp->pcr[i] = pcr_ops->read_pcr(i);
 338                 pp->pic[i] = pcr_ops->read_pic(i);
 339         }
 340 }
 341
 342 static void __global_pmu_poll(struct global_pmu_snapshot *pp)
 343 {
 344         int limit = 0;
 345
 346         while (!pp->pcr[0] && ++limit < 100) {
 347                 barrier();
 348                 udelay(1);
 349         }
 350 }
 351
 352 static void pmu_snapshot_all_cpus(void)
 353 {
 354         unsigned long flags;
 355         int this_cpu, cpu;
 356
 357         spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
 358
 359         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 360
 361         this_cpu = raw_smp_processor_id();
 362
 363         __global_pmu_self(this_cpu);
 364
 365         smp_fetch_global_pmu();
 366
 367         for_each_online_cpu(cpu) {
 368                 struct global_pmu_snapshot *pp = &global_cpu_snapshot[cpu].pmu;
 369
 370                 __global_pmu_poll(pp);
 371
 372                 printk("%c CPU[%3d]: PCR[%08lx:%08lx:%08lx:%08lx] PIC[%08lx:%08lx:%08lx:%08lx]\n",
 373                        (cpu == this_cpu ? '*' : ' '), cpu,
 374                        pp->pcr[0], pp->pcr[1], pp->pcr[2], pp->pcr[3],
 375                        pp->pic[0], pp->pic[1], pp->pic[2], pp->pic[3]);
 376
 377                 touch_nmi_watchdog();
 378         }
 379
 380         memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
 381
 382         spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
 383 }
 384
 385 static void sysrq_handle_globpmu(int key)
 386 {
 387         pmu_snapshot_all_cpus();
 388 }
 389
 390 static const struct sysrq_key_op sparc_globalpmu_op = {
 391         .handler        = sysrq_handle_globpmu,
 392         .help_msg       = "global-pmu(x)",
 393         .action_msg     = "Show Global PMU Regs",
 394 };
 395
 396 static int __init sparc_sysrq_init(void)
 397 {
 398         int ret = register_sysrq_key('y', &sparc_globalreg_op);
 399
 400         if (!ret)
 401                 ret = register_sysrq_key('x', &sparc_globalpmu_op);
 402         return ret;
 403 }
 404
 405 core_initcall(sparc_sysrq_init);
 406
 407 #endif
 408
 409 /* Free current thread data structures etc.. */
 410 void exit_thread(struct task_struct *tsk)
 411 {
 412         struct thread_info *t = task_thread_info(tsk);
 413
 414         if (t->utraps) {
 415                 if (t->utraps[0] < 2)
 416                         kfree (t->utraps);
 417                 else
 418                         t->utraps[0]--;
 419         }
 420 }
 421
 422 void flush_thread(void)
 423 {
 424         struct thread_info *t = current_thread_info();
 425         struct mm_struct *mm;
 426
 427         mm = t->task->mm;
 428         if (mm)
 429                 tsb_context_switch(mm);
 430
 431         set_thread_wsaved(0);
 432
 433         /* Clear FPU register state. */
 434         t->fpsaved[0] = 0;
 435 }
 436
 437 /* It's a bit more tricky when 64-bit tasks are involved... */
 438 static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
 439 {
 440         bool stack_64bit = test_thread_64bit_stack(psp);
 441         unsigned long fp, distance, rval;
 442
 443         if (stack_64bit) {
 444                 csp += STACK_BIAS;
 445                 psp += STACK_BIAS;
 446                 __get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
 447                 fp += STACK_BIAS;
 448                 if (test_thread_flag(TIF_32BIT))
 449                         fp &= 0xffffffff;
 450         } else
 451                 __get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
 452
 453         /* Now align the stack as this is mandatory in the Sparc ABI
 454          * due to how register windows work.  This hides the
 455          * restriction from thread libraries etc.
 456          */
 457         csp &= ~15UL;
 458
 459         distance = fp - psp;
 460         rval = (csp - distance);
 461         if (copy_in_user((void __user *) rval, (void __user *) psp, distance))
 462                 rval = 0;
 463         else if (!stack_64bit) {
 464                 if (put_user(((u32)csp),
 465                              &(((struct reg_window32 __user *)rval)->ins[6])))
 466                         rval = 0;
 467         } else {
 468                 if (put_user(((u64)csp - STACK_BIAS),
 469                              &(((struct reg_window __user *)rval)->ins[6])))
 470                         rval = 0;
 471                 else
 472                         rval = rval - STACK_BIAS;
 473         }
 474
 475         return rval;
 476 }
 477
 478 /* Standard stuff. */
 479 static inline void shift_window_buffer(int first_win, int last_win,
 480                                        struct thread_info *t)
 481 {
 482         int i;
 483
 484         for (i = first_win; i < last_win; i++) {
 485                 t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
 486                 memcpy(&t->reg_window[i], &t->reg_window[i+1],
 487                        sizeof(struct reg_window));
 488         }
 489 }
 490
 491 void synchronize_user_stack(void)
 492 {
 493         struct thread_info *t = current_thread_info();
 494         unsigned long window;
 495
 496         flush_user_windows();
 497         if ((window = get_thread_wsaved()) != 0) {
 498                 window -= 1;
 499                 do {
 500                         struct reg_window *rwin = &t->reg_window[window];
 501                         int winsize = sizeof(struct reg_window);
 502                         unsigned long sp;
 503
 504                         sp = t->rwbuf_stkptrs[window];
 505
 506                         if (test_thread_64bit_stack(sp))
 507                                 sp += STACK_BIAS;
 508                         else
 509                                 winsize = sizeof(struct reg_window32);
 510
 511                         if (!copy_to_user((char __user *)sp, rwin, winsize)) {
 512                                 shift_window_buffer(window, get_thread_wsaved() - 1, t);
 513                                 set_thread_wsaved(get_thread_wsaved() - 1);
 514                         }
 515                 } while (window--);
 516         }
 517 }
 518
 519 static void stack_unaligned(unsigned long sp)
 520 {
 521         force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp, 0);
 522 }
 523
 524 static const char uwfault32[] = KERN_INFO \
 525         "%s[%d]: bad register window fault: SP %08lx (orig_sp %08lx) TPC %08lx O7 %08lx\n";
 526 static const char uwfault64[] = KERN_INFO \
 527         "%s[%d]: bad register window fault: SP %016lx (orig_sp %016lx) TPC %08lx O7 %016lx\n";
 528
 529 void fault_in_user_windows(struct pt_regs *regs)
 530 {
 531         struct thread_info *t = current_thread_info();
 532         unsigned long window;
 533
 534         flush_user_windows();
 535         window = get_thread_wsaved();
 536
 537         if (likely(window != 0)) {
 538                 window -= 1;
 539                 do {
 540                         struct reg_window *rwin = &t->reg_window[window];
 541                         int winsize = sizeof(struct reg_window);
 542                         unsigned long sp, orig_sp;
 543
 544                         orig_sp = sp = t->rwbuf_stkptrs[window];
 545
 546                         if (test_thread_64bit_stack(sp))
 547                                 sp += STACK_BIAS;
 548                         else
 549                                 winsize = sizeof(struct reg_window32);
 550
 551                         if (unlikely(sp & 0x7UL))
 552                                 stack_unaligned(sp);
 553
 554                         if (unlikely(copy_to_user((char __user *)sp,
 555                                                   rwin, winsize))) {
 556                                 if (show_unhandled_signals)
 557                                         printk_ratelimited(is_compat_task() ?
 558                                                            uwfault32 : uwfault64,
 559                                                            current->comm, current->pid,
 560                                                            sp, orig_sp,
 561                                                            regs->tpc,
 562                                                            regs->u_regs[UREG_I7]);
 563                                 goto barf;
 564                         }
 565                 } while (window--);
 566         }
 567         set_thread_wsaved(0);
 568         return;
 569
 570 barf:
 571         set_thread_wsaved(window + 1);
 572         force_sig(SIGSEGV);
 573 }
 574
 575 /* Copy a Sparc thread.  The fork() return value conventions
 576  * under SunOS are nothing short of bletcherous:
 577  * Parent -->  %o0 == childs  pid, %o1 == 0
 578  * Child  -->  %o0 == parents pid, %o1 == 1
 579  */
 580 int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
 581                 struct task_struct *p, unsigned long tls)
 582 {
 583         struct thread_info *t = task_thread_info(p);
 584         struct pt_regs *regs = current_pt_regs();
 585         struct sparc_stackf *parent_sf;
 586         unsigned long child_stack_sz;
 587         char *child_trap_frame;
 588
 589         /* Calculate offset to stack_frame & pt_regs */
 590         child_stack_sz = (STACKFRAME_SZ + TRACEREG_SZ);
 591         child_trap_frame = (task_stack_page(p) +
 592                             (THREAD_SIZE - child_stack_sz));
 593
 594         t->new_child = 1;
 595         t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
 596         t->kregs = (struct pt_regs *) (child_trap_frame +
 597                                        sizeof(struct sparc_stackf));
 598         t->fpsaved[0] = 0;
 599
 600         if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
 601                 memset(child_trap_frame, 0, child_stack_sz);
 602                 __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
 603                         (current_pt_regs()->tstate + 1) & TSTATE_CWP;
 604                 t->current_ds = ASI_P;
 605                 t->kregs->u_regs[UREG_G1] = sp; /* function */
 606                 t->kregs->u_regs[UREG_G2] = arg;
 607                 return 0;
 608         }
 609
 610         parent_sf = ((struct sparc_stackf *) regs) - 1;
 611         memcpy(child_trap_frame, parent_sf, child_stack_sz);
 612         if (t->flags & _TIF_32BIT) {
 613                 sp &= 0x00000000ffffffffUL;
 614                 regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
 615         }
 616         t->kregs->u_regs[UREG_FP] = sp;
 617         __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
 618                 (regs->tstate + 1) & TSTATE_CWP;
 619         t->current_ds = ASI_AIUS;
 620         if (sp != regs->u_regs[UREG_FP]) {
 621                 unsigned long csp;
 622
 623                 csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
 624                 if (!csp)
 625                         return -EFAULT;
 626                 t->kregs->u_regs[UREG_FP] = csp;
 627         }
 628         if (t->utraps)
 629                 t->utraps[0]++;
 630
 631         /* Set the return value for the child. */
 632         t->kregs->u_regs[UREG_I0] = current->pid;
 633         t->kregs->u_regs[UREG_I1] = 1;
 634
 635         /* Set the second return value for the parent. */
 636         regs->u_regs[UREG_I1] = 0;
 637
 638         if (clone_flags & CLONE_SETTLS)
 639                 t->kregs->u_regs[UREG_G7] = tls;
 640
 641         return 0;
 642 }
 643
 644 /* TIF_MCDPER in thread info flags for current task is updated lazily upon
 645  * a context switch. Update this flag in current task's thread flags
 646  * before dup so the dup'd task will inherit the current TIF_MCDPER flag.
 647  */
 648 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 649 {
 650         if (adi_capable()) {
 651                 register unsigned long tmp_mcdper;
 652
 653                 __asm__ __volatile__(
 654                         ".word 0x83438000\n\t"  /* rd  %mcdper, %g1 */
 655                         "mov %%g1, %0\n\t"
 656                         : "=r" (tmp_mcdper)
 657                         :
 658                         : "g1");
 659                 if (tmp_mcdper)
 660                         set_thread_flag(TIF_MCDPER);
 661                 else
 662                         clear_thread_flag(TIF_MCDPER);
 663         }
 664
 665         *dst = *src;
 666         return 0;
 667 }
 668
 669 unsigned long get_wchan(struct task_struct *task)
 670 {
 671         unsigned long pc, fp, bias = 0;
 672         struct thread_info *tp;
 673         struct reg_window *rw;
 674         unsigned long ret = 0;
 675         int count = 0;
 676
 677         if (!task || task == current ||
 678             task->state == TASK_RUNNING)
 679                 goto out;
 680
 681         tp = task_thread_info(task);
 682         bias = STACK_BIAS;
 683         fp = task_thread_info(task)->ksp + bias;
 684
 685         do {
 686                 if (!kstack_valid(tp, fp))
 687                         break;
 688                 rw = (struct reg_window *) fp;
 689                 pc = rw->ins[7];
 690                 if (!in_sched_functions(pc)) {
 691                         ret = pc;
 692                         goto out;
 693                 }
 694                 fp = rw->ins[6] + bias;
 695         } while (++count < 16);
 696
 697 out:
 698         return ret;
 699 }