arch/sparc64/kernel/process.c

   1 /*  arch/sparc64/kernel/process.c
   2  *
   3  *  Copyright (C) 1995, 1996, 2008 David S. Miller (davem@davemloft.net)
   4  *  Copyright (C) 1996       Eddie C. Dost   (ecd@skynet.be)
   5  *  Copyright (C) 1997, 1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
   6  */
   7
   8 /*
   9  * This file handles the architecture-dependent parts of process handling..
  10  */
  11
  12 #include <stdarg.h>
  13
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mm.h>
  19 #include <linux/fs.h>
  20 #include <linux/smp.h>
  21 #include <linux/stddef.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/slab.h>
  24 #include <linux/user.h>
  25 #include <linux/reboot.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/elfcore.h>
  32 #include <linux/sysrq.h>
  33
  34 #include <asm/oplib.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/system.h>
  37 #include <asm/page.h>
  38 #include <asm/pgalloc.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/processor.h>
  41 #include <asm/pstate.h>
  42 #include <asm/elf.h>
  43 #include <asm/fpumacro.h>
  44 #include <asm/head.h>
  45 #include <asm/cpudata.h>
  46 #include <asm/mmu_context.h>
  47 #include <asm/unistd.h>
  48 #include <asm/hypervisor.h>
  49 #include <asm/sstate.h>
  50 #include <asm/reboot.h>
  51 #include <asm/syscalls.h>
  52 #include <asm/irq_regs.h>
  53 #include <asm/smp.h>
  54
  55 static void sparc64_yield(int cpu)
  56 {
  57         if (tlb_type != hypervisor)
  58                 return;
  59
  60         clear_thread_flag(TIF_POLLING_NRFLAG);
  61         smp_mb__after_clear_bit();
  62
  63         while (!need_resched() && !cpu_is_offline(cpu)) {
  64                 unsigned long pstate;
  65
  66                 /* Disable interrupts. */
  67                 __asm__ __volatile__(
  68                         "rdpr %%pstate, %0\n\t"
  69                         "andn %0, %1, %0\n\t"
  70                         "wrpr %0, %%g0, %%pstate"
  71                         : "=&r" (pstate)
  72                         : "i" (PSTATE_IE));
  73
  74                 if (!need_resched() && !cpu_is_offline(cpu))
  75                         sun4v_cpu_yield();
  76
  77                 /* Re-enable interrupts. */
  78                 __asm__ __volatile__(
  79                         "rdpr %%pstate, %0\n\t"
  80                         "or %0, %1, %0\n\t"
  81                         "wrpr %0, %%g0, %%pstate"
  82                         : "=&r" (pstate)
  83                         : "i" (PSTATE_IE));
  84         }
  85
  86         set_thread_flag(TIF_POLLING_NRFLAG);
  87 }
  88
  89 /* The idle loop on sparc64. */
  90 void cpu_idle(void)
  91 {
  92         int cpu = smp_processor_id();
  93
  94         set_thread_flag(TIF_POLLING_NRFLAG);
  95
  96         while(1) {
  97                 tick_nohz_stop_sched_tick(1);
  98
  99                 while (!need_resched() && !cpu_is_offline(cpu))
 100                         sparc64_yield(cpu);
 101
 102                 tick_nohz_restart_sched_tick();
 103
 104                 preempt_enable_no_resched();
 105
 106 #ifdef CONFIG_HOTPLUG_CPU
 107                 if (cpu_is_offline(cpu))
 108                         cpu_play_dead();
 109 #endif
 110
 111                 schedule();
 112                 preempt_disable();
 113         }
 114 }
 115
 116 void machine_halt(void)
 117 {
 118         sstate_halt();
 119         prom_halt();
 120         panic("Halt failed!");
 121 }
 122
 123 void machine_alt_power_off(void)
 124 {
 125         sstate_poweroff();
 126         prom_halt_power_off();
 127         panic("Power-off failed!");
 128 }
 129
 130 void machine_restart(char * cmd)
 131 {
 132         char *p;
 133
 134         sstate_reboot();
 135         p = strchr (reboot_command, '\n');
 136         if (p) *p = 0;
 137         if (cmd)
 138                 prom_reboot(cmd);
 139         if (*reboot_command)
 140                 prom_reboot(reboot_command);
 141         prom_reboot("");
 142         panic("Reboot failed!");
 143 }
 144
 145 #ifdef CONFIG_COMPAT
 146 static void show_regwindow32(struct pt_regs *regs)
 147 {
 148         struct reg_window32 __user *rw;
 149         struct reg_window32 r_w;
 150         mm_segment_t old_fs;
 151
 152         __asm__ __volatile__ ("flushw");
 153         rw = compat_ptr((unsigned)regs->u_regs[14]);
 154         old_fs = get_fs();
 155         set_fs (USER_DS);
 156         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 157                 set_fs (old_fs);
 158                 return;
 159         }
 160
 161         set_fs (old_fs);
 162         printk("l0: %08x l1: %08x l2: %08x l3: %08x "
 163                "l4: %08x l5: %08x l6: %08x l7: %08x\n",
 164                r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
 165                r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
 166         printk("i0: %08x i1: %08x i2: %08x i3: %08x "
 167                "i4: %08x i5: %08x i6: %08x i7: %08x\n",
 168                r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
 169                r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
 170 }
 171 #else
 172 #define show_regwindow32(regs)  do { } while (0)
 173 #endif
 174
 175 static void show_regwindow(struct pt_regs *regs)
 176 {
 177         struct reg_window __user *rw;
 178         struct reg_window *rwk;
 179         struct reg_window r_w;
 180         mm_segment_t old_fs;
 181
 182         if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
 183                 __asm__ __volatile__ ("flushw");
 184                 rw = (struct reg_window __user *)
 185                         (regs->u_regs[14] + STACK_BIAS);
 186                 rwk = (struct reg_window *)
 187                         (regs->u_regs[14] + STACK_BIAS);
 188                 if (!(regs->tstate & TSTATE_PRIV)) {
 189                         old_fs = get_fs();
 190                         set_fs (USER_DS);
 191                         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 192                                 set_fs (old_fs);
 193                                 return;
 194                         }
 195                         rwk = &r_w;
 196                         set_fs (old_fs);
 197                 }
 198         } else {
 199                 show_regwindow32(regs);
 200                 return;
 201         }
 202         printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
 203                rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
 204         printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
 205                rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
 206         printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
 207                rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
 208         printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
 209                rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
 210         if (regs->tstate & TSTATE_PRIV)
 211                 printk("I7: <%pS>\n", (void *) rwk->ins[7]);
 212 }
 213
 214 #ifdef CONFIG_SMP
 215 static DEFINE_SPINLOCK(regdump_lock);
 216 #endif
 217
 218 void __show_regs(struct pt_regs * regs)
 219 {
 220 #ifdef CONFIG_SMP
 221         unsigned long flags;
 222
 223         /* Protect against xcall ipis which might lead to livelock on the lock */
 224         __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
 225                              "wrpr      %0, %1, %%pstate"
 226                              : "=r" (flags)
 227                              : "i" (PSTATE_IE));
 228         spin_lock(&regdump_lock);
 229 #endif
 230         printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
 231                regs->tpc, regs->tnpc, regs->y, print_tainted());
 232         printk("TPC: <%pS>\n", (void *) regs->tpc);
 233         printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
 234                regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
 235                regs->u_regs[3]);
 236         printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
 237                regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
 238                regs->u_regs[7]);
 239         printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
 240                regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
 241                regs->u_regs[11]);
 242         printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
 243                regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
 244                regs->u_regs[15]);
 245         printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
 246         show_regwindow(regs);
 247 #ifdef CONFIG_SMP
 248         spin_unlock(&regdump_lock);
 249         __asm__ __volatile__("wrpr      %0, 0, %%pstate"
 250                              : : "r" (flags));
 251 #endif
 252 }
 253
 254 void show_regs(struct pt_regs *regs)
 255 {
 256         __show_regs(regs);
 257 }
 258
 259 struct global_reg_snapshot global_reg_snapshot[NR_CPUS];
 260 static DEFINE_SPINLOCK(global_reg_snapshot_lock);
 261
 262 static bool kstack_valid(struct thread_info *tp, struct reg_window *rw)
 263 {
 264         unsigned long thread_base, fp;
 265
 266         thread_base = (unsigned long) tp;
 267         fp = (unsigned long) rw;
 268
 269         if (fp < (thread_base + sizeof(struct thread_info)) ||
 270             fp >= (thread_base + THREAD_SIZE))
 271                 return false;
 272         return true;
 273 }
 274
 275 static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
 276                               int this_cpu)
 277 {
 278         flushw_all();
 279
 280         global_reg_snapshot[this_cpu].tstate = regs->tstate;
 281         global_reg_snapshot[this_cpu].tpc = regs->tpc;
 282         global_reg_snapshot[this_cpu].tnpc = regs->tnpc;
 283         global_reg_snapshot[this_cpu].o7 = regs->u_regs[UREG_I7];
 284
 285         if (regs->tstate & TSTATE_PRIV) {
 286                 struct thread_info *tp = current_thread_info();
 287                 struct reg_window *rw;
 288
 289                 rw = (struct reg_window *)
 290                         (regs->u_regs[UREG_FP] + STACK_BIAS);
 291                 if (kstack_valid(tp, rw)) {
 292                         global_reg_snapshot[this_cpu].i7 = rw->ins[7];
 293                         rw = (struct reg_window *)
 294                                 (rw->ins[6] + STACK_BIAS);
 295                         if (kstack_valid(tp, rw))
 296                                 global_reg_snapshot[this_cpu].rpc = rw->ins[7];
 297                 }
 298         } else {
 299                 global_reg_snapshot[this_cpu].i7 = 0;
 300                 global_reg_snapshot[this_cpu].rpc = 0;
 301         }
 302         global_reg_snapshot[this_cpu].thread = tp;
 303 }
 304
 305 /* In order to avoid hangs we do not try to synchronize with the
 306  * global register dump client cpus.  The last store they make is to
 307  * the thread pointer, so do a short poll waiting for that to become
 308  * non-NULL.
 309  */
 310 static void __global_reg_poll(struct global_reg_snapshot *gp)
 311 {
 312         int limit = 0;
 313
 314         while (!gp->thread && ++limit < 100) {
 315                 barrier();
 316                 udelay(1);
 317         }
 318 }
 319
 320 void __trigger_all_cpu_backtrace(void)
 321 {
 322         struct thread_info *tp = current_thread_info();
 323         struct pt_regs *regs = get_irq_regs();
 324         unsigned long flags;
 325         int this_cpu, cpu;
 326
 327         if (!regs)
 328                 regs = tp->kregs;
 329
 330         spin_lock_irqsave(&global_reg_snapshot_lock, flags);
 331
 332         memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));
 333
 334         this_cpu = raw_smp_processor_id();
 335
 336         __global_reg_self(tp, regs, this_cpu);
 337
 338         smp_fetch_global_regs();
 339
 340         for_each_online_cpu(cpu) {
 341                 struct global_reg_snapshot *gp = &global_reg_snapshot[cpu];
 342                 struct thread_info *tp;
 343
 344                 __global_reg_poll(gp);
 345
 346                 tp = gp->thread;
 347                 printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
 348                        (cpu == this_cpu ? '*' : ' '), cpu,
 349                        gp->tstate, gp->tpc, gp->tnpc,
 350                        ((tp && tp->task) ? tp->task->comm : "NULL"),
 351                        ((tp && tp->task) ? tp->task->pid : -1));
 352
 353                 if (gp->tstate & TSTATE_PRIV) {
 354                         printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
 355                                (void *) gp->tpc,
 356                                (void *) gp->o7,
 357                                (void *) gp->i7,
 358                                (void *) gp->rpc);
 359                 } else {
 360                         printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
 361                                gp->tpc, gp->o7, gp->i7, gp->rpc);
 362                 }
 363         }
 364
 365         memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));
 366
 367         spin_unlock_irqrestore(&global_reg_snapshot_lock, flags);
 368 }
 369
 370 #ifdef CONFIG_MAGIC_SYSRQ
 371
 372 static void sysrq_handle_globreg(int key, struct tty_struct *tty)
 373 {
 374         __trigger_all_cpu_backtrace();
 375 }
 376
 377 static struct sysrq_key_op sparc_globalreg_op = {
 378         .handler        = sysrq_handle_globreg,
 379         .help_msg       = "Globalregs",
 380         .action_msg     = "Show Global CPU Regs",
 381 };
 382
 383 static int __init sparc_globreg_init(void)
 384 {
 385         return register_sysrq_key('y', &sparc_globalreg_op);
 386 }
 387
 388 core_initcall(sparc_globreg_init);
 389
 390 #endif
 391
 392 unsigned long thread_saved_pc(struct task_struct *tsk)
 393 {
 394         struct thread_info *ti = task_thread_info(tsk);
 395         unsigned long ret = 0xdeadbeefUL;
 396
 397         if (ti && ti->ksp) {
 398                 unsigned long *sp;
 399                 sp = (unsigned long *)(ti->ksp + STACK_BIAS);
 400                 if (((unsigned long)sp & (sizeof(long) - 1)) == 0UL &&
 401                     sp[14]) {
 402                         unsigned long *fp;
 403                         fp = (unsigned long *)(sp[14] + STACK_BIAS);
 404                         if (((unsigned long)fp & (sizeof(long) - 1)) == 0UL)
 405                                 ret = fp[15];
 406                 }
 407         }
 408         return ret;
 409 }
 410
 411 /* Free current thread data structures etc.. */
 412 void exit_thread(void)
 413 {
 414         struct thread_info *t = current_thread_info();
 415
 416         if (t->utraps) {
 417                 if (t->utraps[0] < 2)
 418                         kfree (t->utraps);
 419                 else
 420                         t->utraps[0]--;
 421         }
 422
 423         if (test_and_clear_thread_flag(TIF_PERFCTR)) {
 424                 t->user_cntd0 = t->user_cntd1 = NULL;
 425                 t->pcr_reg = 0;
 426                 write_pcr(0);
 427         }
 428 }
 429
 430 void flush_thread(void)
 431 {
 432         struct thread_info *t = current_thread_info();
 433         struct mm_struct *mm;
 434
 435         if (test_ti_thread_flag(t, TIF_ABI_PENDING)) {
 436                 clear_ti_thread_flag(t, TIF_ABI_PENDING);
 437                 if (test_ti_thread_flag(t, TIF_32BIT))
 438                         clear_ti_thread_flag(t, TIF_32BIT);
 439                 else
 440                         set_ti_thread_flag(t, TIF_32BIT);
 441         }
 442
 443         mm = t->task->mm;
 444         if (mm)
 445                 tsb_context_switch(mm);
 446
 447         set_thread_wsaved(0);
 448
 449         /* Turn off performance counters if on. */
 450         if (test_and_clear_thread_flag(TIF_PERFCTR)) {
 451                 t->user_cntd0 = t->user_cntd1 = NULL;
 452                 t->pcr_reg = 0;
 453                 write_pcr(0);
 454         }
 455
 456         /* Clear FPU register state. */
 457         t->fpsaved[0] = 0;
 458
 459         if (get_thread_current_ds() != ASI_AIUS)
 460                 set_fs(USER_DS);
 461 }
 462
 463 /* It's a bit more tricky when 64-bit tasks are involved... */
 464 static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
 465 {
 466         unsigned long fp, distance, rval;
 467
 468         if (!(test_thread_flag(TIF_32BIT))) {
 469                 csp += STACK_BIAS;
 470                 psp += STACK_BIAS;
 471                 __get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
 472                 fp += STACK_BIAS;
 473         } else
 474                 __get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
 475
 476         /* Now 8-byte align the stack as this is mandatory in the
 477          * Sparc ABI due to how register windows work.  This hides
 478          * the restriction from thread libraries etc.  -DaveM
 479          */
 480         csp &= ~7UL;
 481
 482         distance = fp - psp;
 483         rval = (csp - distance);
 484         if (copy_in_user((void __user *) rval, (void __user *) psp, distance))
 485                 rval = 0;
 486         else if (test_thread_flag(TIF_32BIT)) {
 487                 if (put_user(((u32)csp),
 488                              &(((struct reg_window32 __user *)rval)->ins[6])))
 489                         rval = 0;
 490         } else {
 491                 if (put_user(((u64)csp - STACK_BIAS),
 492                              &(((struct reg_window __user *)rval)->ins[6])))
 493                         rval = 0;
 494                 else
 495                         rval = rval - STACK_BIAS;
 496         }
 497
 498         return rval;
 499 }
 500
 501 /* Standard stuff. */
 502 static inline void shift_window_buffer(int first_win, int last_win,
 503                                        struct thread_info *t)
 504 {
 505         int i;
 506
 507         for (i = first_win; i < last_win; i++) {
 508                 t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
 509                 memcpy(&t->reg_window[i], &t->reg_window[i+1],
 510                        sizeof(struct reg_window));
 511         }
 512 }
 513
 514 void synchronize_user_stack(void)
 515 {
 516         struct thread_info *t = current_thread_info();
 517         unsigned long window;
 518
 519         flush_user_windows();
 520         if ((window = get_thread_wsaved()) != 0) {
 521                 int winsize = sizeof(struct reg_window);
 522                 int bias = 0;
 523
 524                 if (test_thread_flag(TIF_32BIT))
 525                         winsize = sizeof(struct reg_window32);
 526                 else
 527                         bias = STACK_BIAS;
 528
 529                 window -= 1;
 530                 do {
 531                         unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
 532                         struct reg_window *rwin = &t->reg_window[window];
 533
 534                         if (!copy_to_user((char __user *)sp, rwin, winsize)) {
 535                                 shift_window_buffer(window, get_thread_wsaved() - 1, t);
 536                                 set_thread_wsaved(get_thread_wsaved() - 1);
 537                         }
 538                 } while (window--);
 539         }
 540 }
 541
 542 static void stack_unaligned(unsigned long sp)
 543 {
 544         siginfo_t info;
 545
 546         info.si_signo = SIGBUS;
 547         info.si_errno = 0;
 548         info.si_code = BUS_ADRALN;
 549         info.si_addr = (void __user *) sp;
 550         info.si_trapno = 0;
 551         force_sig_info(SIGBUS, &info, current);
 552 }
 553
 554 void fault_in_user_windows(void)
 555 {
 556         struct thread_info *t = current_thread_info();
 557         unsigned long window;
 558         int winsize = sizeof(struct reg_window);
 559         int bias = 0;
 560
 561         if (test_thread_flag(TIF_32BIT))
 562                 winsize = sizeof(struct reg_window32);
 563         else
 564                 bias = STACK_BIAS;
 565
 566         flush_user_windows();
 567         window = get_thread_wsaved();
 568
 569         if (likely(window != 0)) {
 570                 window -= 1;
 571                 do {
 572                         unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
 573                         struct reg_window *rwin = &t->reg_window[window];
 574
 575                         if (unlikely(sp & 0x7UL))
 576                                 stack_unaligned(sp);
 577
 578                         if (unlikely(copy_to_user((char __user *)sp,
 579                                                   rwin, winsize)))
 580                                 goto barf;
 581                 } while (window--);
 582         }
 583         set_thread_wsaved(0);
 584         return;
 585
 586 barf:
 587         set_thread_wsaved(window + 1);
 588         do_exit(SIGILL);
 589 }
 590
 591 asmlinkage long sparc_do_fork(unsigned long clone_flags,
 592                               unsigned long stack_start,
 593                               struct pt_regs *regs,
 594                               unsigned long stack_size)
 595 {
 596         int __user *parent_tid_ptr, *child_tid_ptr;
 597         unsigned long orig_i1 = regs->u_regs[UREG_I1];
 598         long ret;
 599
 600 #ifdef CONFIG_COMPAT
 601         if (test_thread_flag(TIF_32BIT)) {
 602                 parent_tid_ptr = compat_ptr(regs->u_regs[UREG_I2]);
 603                 child_tid_ptr = compat_ptr(regs->u_regs[UREG_I4]);
 604         } else
 605 #endif
 606         {
 607                 parent_tid_ptr = (int __user *) regs->u_regs[UREG_I2];
 608                 child_tid_ptr = (int __user *) regs->u_regs[UREG_I4];
 609         }
 610
 611         ret = do_fork(clone_flags, stack_start,
 612                       regs, stack_size,
 613                       parent_tid_ptr, child_tid_ptr);
 614
 615         /* If we get an error and potentially restart the system
 616          * call, we're screwed because copy_thread() clobbered
 617          * the parent's %o1.  So detect that case and restore it
 618          * here.
 619          */
 620         if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 621                 regs->u_regs[UREG_I1] = orig_i1;
 622
 623         return ret;
 624 }
 625
 626 /* Copy a Sparc thread.  The fork() return value conventions
 627  * under SunOS are nothing short of bletcherous:
 628  * Parent -->  %o0 == childs  pid, %o1 == 0
 629  * Child  -->  %o0 == parents pid, %o1 == 1
 630  */
 631 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 632                 unsigned long unused,
 633                 struct task_struct *p, struct pt_regs *regs)
 634 {
 635         struct thread_info *t = task_thread_info(p);
 636         struct sparc_stackf *parent_sf;
 637         unsigned long child_stack_sz;
 638         char *child_trap_frame;
 639         int kernel_thread;
 640
 641         kernel_thread = (regs->tstate & TSTATE_PRIV) ? 1 : 0;
 642         parent_sf = ((struct sparc_stackf *) regs) - 1;
 643
 644         /* Calculate offset to stack_frame & pt_regs */
 645         child_stack_sz = ((STACKFRAME_SZ + TRACEREG_SZ) +
 646                           (kernel_thread ? STACKFRAME_SZ : 0));
 647         child_trap_frame = (task_stack_page(p) +
 648                             (THREAD_SIZE - child_stack_sz));
 649         memcpy(child_trap_frame, parent_sf, child_stack_sz);
 650
 651         t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) |
 652                                  (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
 653                 (((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
 654         t->new_child = 1;
 655         t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
 656         t->kregs = (struct pt_regs *) (child_trap_frame +
 657                                        sizeof(struct sparc_stackf));
 658         t->fpsaved[0] = 0;
 659
 660         if (kernel_thread) {
 661                 struct sparc_stackf *child_sf = (struct sparc_stackf *)
 662                         (child_trap_frame + (STACKFRAME_SZ + TRACEREG_SZ));
 663
 664                 /* Zero terminate the stack backtrace.  */
 665                 child_sf->fp = NULL;
 666                 t->kregs->u_regs[UREG_FP] =
 667                   ((unsigned long) child_sf) - STACK_BIAS;
 668
 669                 /* Special case, if we are spawning a kernel thread from
 670                  * a userspace task (usermode helper, NFS or similar), we
 671                  * must disable performance counters in the child because
 672                  * the address space and protection realm are changing.
 673                  */
 674                 if (t->flags & _TIF_PERFCTR) {
 675                         t->user_cntd0 = t->user_cntd1 = NULL;
 676                         t->pcr_reg = 0;
 677                         t->flags &= ~_TIF_PERFCTR;
 678                 }
 679                 t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
 680                 t->kregs->u_regs[UREG_G6] = (unsigned long) t;
 681                 t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
 682         } else {
 683                 if (t->flags & _TIF_32BIT) {
 684                         sp &= 0x00000000ffffffffUL;
 685                         regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
 686                 }
 687                 t->kregs->u_regs[UREG_FP] = sp;
 688                 t->flags |= ((long)ASI_AIUS << TI_FLAG_CURRENT_DS_SHIFT);
 689                 if (sp != regs->u_regs[UREG_FP]) {
 690                         unsigned long csp;
 691
 692                         csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
 693                         if (!csp)
 694                                 return -EFAULT;
 695                         t->kregs->u_regs[UREG_FP] = csp;
 696                 }
 697                 if (t->utraps)
 698                         t->utraps[0]++;
 699         }
 700
 701         /* Set the return value for the child. */
 702         t->kregs->u_regs[UREG_I0] = current->pid;
 703         t->kregs->u_regs[UREG_I1] = 1;
 704
 705         /* Set the second return value for the parent. */
 706         regs->u_regs[UREG_I1] = 0;
 707
 708         if (clone_flags & CLONE_SETTLS)
 709                 t->kregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 710
 711         return 0;
 712 }
 713
 714 /*
 715  * This is the mechanism for creating a new kernel thread.
 716  *
 717  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 718  * who haven't done an "execve()") should use this: it will work within
 719  * a system call from a "real" process, but the process memory space will
 720  * not be freed until both the parent and the child have exited.
 721  */
 722 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 723 {
 724         long retval;
 725
 726         /* If the parent runs before fn(arg) is called by the child,
 727          * the input registers of this function can be clobbered.
 728          * So we stash 'fn' and 'arg' into global registers which
 729          * will not be modified by the parent.
 730          */
 731         __asm__ __volatile__("mov %4, %%g2\n\t"    /* Save FN into global */
 732                              "mov %5, %%g3\n\t"    /* Save ARG into global */
 733                              "mov %1, %%g1\n\t"    /* Clone syscall nr. */
 734                              "mov %2, %%o0\n\t"    /* Clone flags. */
 735                              "mov 0, %%o1\n\t"     /* usp arg == 0 */
 736                              "t 0x6d\n\t"          /* Linux/Sparc clone(). */
 737                              "brz,a,pn %%o1, 1f\n\t" /* Parent, just return. */
 738                              " mov %%o0, %0\n\t"
 739                              "jmpl %%g2, %%o7\n\t"   /* Call the function. */
 740                              " mov %%g3, %%o0\n\t"   /* Set arg in delay. */
 741                              "mov %3, %%g1\n\t"
 742                              "t 0x6d\n\t"          /* Linux/Sparc exit(). */
 743                              /* Notreached by child. */
 744                              "1:" :
 745                              "=r" (retval) :
 746                              "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
 747                              "i" (__NR_exit),  "r" (fn), "r" (arg) :
 748                              "g1", "g2", "g3", "o0", "o1", "memory", "cc");
 749         return retval;
 750 }
 751
 752 typedef struct {
 753         union {
 754                 unsigned int    pr_regs[32];
 755                 unsigned long   pr_dregs[16];
 756         } pr_fr;
 757         unsigned int __unused;
 758         unsigned int    pr_fsr;
 759         unsigned char   pr_qcnt;
 760         unsigned char   pr_q_entrysize;
 761         unsigned char   pr_en;
 762         unsigned int    pr_q[64];
 763 } elf_fpregset_t32;
 764
 765 /*
 766  * fill in the fpu structure for a core dump.
 767  */
 768 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 769 {
 770         unsigned long *kfpregs = current_thread_info()->fpregs;
 771         unsigned long fprs = current_thread_info()->fpsaved[0];
 772
 773         if (test_thread_flag(TIF_32BIT)) {
 774                 elf_fpregset_t32 *fpregs32 = (elf_fpregset_t32 *)fpregs;
 775
 776                 if (fprs & FPRS_DL)
 777                         memcpy(&fpregs32->pr_fr.pr_regs[0], kfpregs,
 778                                sizeof(unsigned int) * 32);
 779                 else
 780                         memset(&fpregs32->pr_fr.pr_regs[0], 0,
 781                                sizeof(unsigned int) * 32);
 782                 fpregs32->pr_qcnt = 0;
 783                 fpregs32->pr_q_entrysize = 8;
 784                 memset(&fpregs32->pr_q[0], 0,
 785                        (sizeof(unsigned int) * 64));
 786                 if (fprs & FPRS_FEF) {
 787                         fpregs32->pr_fsr = (unsigned int) current_thread_info()->xfsr[0];
 788                         fpregs32->pr_en = 1;
 789                 } else {
 790                         fpregs32->pr_fsr = 0;
 791                         fpregs32->pr_en = 0;
 792                 }
 793         } else {
 794                 if(fprs & FPRS_DL)
 795                         memcpy(&fpregs->pr_regs[0], kfpregs,
 796                                sizeof(unsigned int) * 32);
 797                 else
 798                         memset(&fpregs->pr_regs[0], 0,
 799                                sizeof(unsigned int) * 32);
 800                 if(fprs & FPRS_DU)
 801                         memcpy(&fpregs->pr_regs[16], kfpregs+16,
 802                                sizeof(unsigned int) * 32);
 803                 else
 804                         memset(&fpregs->pr_regs[16], 0,
 805                                sizeof(unsigned int) * 32);
 806                 if(fprs & FPRS_FEF) {
 807                         fpregs->pr_fsr = current_thread_info()->xfsr[0];
 808                         fpregs->pr_gsr = current_thread_info()->gsr[0];
 809                 } else {
 810                         fpregs->pr_fsr = fpregs->pr_gsr = 0;
 811                 }
 812                 fpregs->pr_fprs = fprs;
 813         }
 814         return 1;
 815 }
 816
 817 /*
 818  * sparc_execve() executes a new program after the asm stub has set
 819  * things up for us.  This should basically do what I want it to.
 820  */
 821 asmlinkage int sparc_execve(struct pt_regs *regs)
 822 {
 823         int error, base = 0;
 824         char *filename;
 825
 826         /* User register window flush is done by entry.S */
 827
 828         /* Check for indirect call. */
 829         if (regs->u_regs[UREG_G1] == 0)
 830                 base = 1;
 831
 832         filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
 833         error = PTR_ERR(filename);
 834         if (IS_ERR(filename))
 835                 goto out;
 836         error = do_execve(filename,
 837                           (char __user * __user *)
 838                           regs->u_regs[base + UREG_I1],
 839                           (char __user * __user *)
 840                           regs->u_regs[base + UREG_I2], regs);
 841         putname(filename);
 842         if (!error) {
 843                 fprs_write(0);
 844                 current_thread_info()->xfsr[0] = 0;
 845                 current_thread_info()->fpsaved[0] = 0;
 846                 regs->tstate &= ~TSTATE_PEF;
 847         }
 848 out:
 849         return error;
 850 }
 851
 852 unsigned long get_wchan(struct task_struct *task)
 853 {
 854         unsigned long pc, fp, bias = 0;
 855         unsigned long thread_info_base;
 856         struct reg_window *rw;
 857         unsigned long ret = 0;
 858         int count = 0;
 859
 860         if (!task || task == current ||
 861             task->state == TASK_RUNNING)
 862                 goto out;
 863
 864         thread_info_base = (unsigned long) task_stack_page(task);
 865         bias = STACK_BIAS;
 866         fp = task_thread_info(task)->ksp + bias;
 867
 868         do {
 869                 /* Bogus frame pointer? */
 870                 if (fp < (thread_info_base + sizeof(struct thread_info)) ||
 871                     fp >= (thread_info_base + THREAD_SIZE))
 872                         break;
 873                 rw = (struct reg_window *) fp;
 874                 pc = rw->ins[7];
 875                 if (!in_sched_functions(pc)) {
 876                         ret = pc;
 877                         goto out;
 878                 }
 879                 fp = rw->ins[6] + bias;
 880         } while (++count < 16);
 881
 882 out:
 883         return ret;
 884 }