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