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