arch/sparc/kernel/process_64.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/delay.h>
  26 #include <linux/compat.h>
  27 #include <linux/tick.h>
  28 #include <linux/init.h>
  29 #include <linux/cpu.h>
  30 #include <linux/elfcore.h>
  31 #include <linux/sysrq.h>
  32 #include <linux/nmi.h>
  33
  34 #include <asm/uaccess.h>
  35 #include <asm/system.h>
  36 #include <asm/page.h>
  37 #include <asm/pgalloc.h>
  38 #include <asm/pgtable.h>
  39 #include <asm/processor.h>
  40 #include <asm/pstate.h>
  41 #include <asm/elf.h>
  42 #include <asm/fpumacro.h>
  43 #include <asm/head.h>
  44 #include <asm/cpudata.h>
  45 #include <asm/mmu_context.h>
  46 #include <asm/unistd.h>
  47 #include <asm/hypervisor.h>
  48 #include <asm/syscalls.h>
  49 #include <asm/irq_regs.h>
  50 #include <asm/smp.h>
  51
  52 #include "kstack.h"
  53
  54 static void sparc64_yield(int cpu)
  55 {
  56         if (tlb_type != hypervisor) {
  57                 touch_nmi_watchdog();
  58                 return;
  59         }
  60
  61         clear_thread_flag(TIF_POLLING_NRFLAG);
  62         smp_mb__after_clear_bit();
  63
  64         while (!need_resched() && !cpu_is_offline(cpu)) {
  65                 unsigned long pstate;
  66
  67                 /* Disable interrupts. */
  68                 __asm__ __volatile__(
  69                         "rdpr %%pstate, %0\n\t"
  70                         "andn %0, %1, %0\n\t"
  71                         "wrpr %0, %%g0, %%pstate"
  72                         : "=&r" (pstate)
  73                         : "i" (PSTATE_IE));
  74
  75                 if (!need_resched() && !cpu_is_offline(cpu))
  76                         sun4v_cpu_yield();
  77
  78                 /* Re-enable interrupts. */
  79                 __asm__ __volatile__(
  80                         "rdpr %%pstate, %0\n\t"
  81                         "or %0, %1, %0\n\t"
  82                         "wrpr %0, %%g0, %%pstate"
  83                         : "=&r" (pstate)
  84                         : "i" (PSTATE_IE));
  85         }
  86
  87         set_thread_flag(TIF_POLLING_NRFLAG);
  88 }
  89
  90 /* The idle loop on sparc64. */
  91 void cpu_idle(void)
  92 {
  93         int cpu = smp_processor_id();
  94
  95         set_thread_flag(TIF_POLLING_NRFLAG);
  96
  97         while(1) {
  98                 tick_nohz_stop_sched_tick(1);
  99
 100                 while (!need_resched() && !cpu_is_offline(cpu))
 101                         sparc64_yield(cpu);
 102
 103                 tick_nohz_restart_sched_tick();
 104
 105                 preempt_enable_no_resched();
 106
 107 #ifdef CONFIG_HOTPLUG_CPU
 108                 if (cpu_is_offline(cpu))
 109                         cpu_play_dead();
 110 #endif
 111
 112                 schedule();
 113                 preempt_disable();
 114         }
 115 }
 116
 117 #ifdef CONFIG_COMPAT
 118 static void show_regwindow32(struct pt_regs *regs)
 119 {
 120         struct reg_window32 __user *rw;
 121         struct reg_window32 r_w;
 122         mm_segment_t old_fs;
 123
 124         __asm__ __volatile__ ("flushw");
 125         rw = compat_ptr((unsigned)regs->u_regs[14]);
 126         old_fs = get_fs();
 127         set_fs (USER_DS);
 128         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 129                 set_fs (old_fs);
 130                 return;
 131         }
 132
 133         set_fs (old_fs);
 134         printk("l0: %08x l1: %08x l2: %08x l3: %08x "
 135                "l4: %08x l5: %08x l6: %08x l7: %08x\n",
 136                r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
 137                r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
 138         printk("i0: %08x i1: %08x i2: %08x i3: %08x "
 139                "i4: %08x i5: %08x i6: %08x i7: %08x\n",
 140                r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
 141                r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
 142 }
 143 #else
 144 #define show_regwindow32(regs)  do { } while (0)
 145 #endif
 146
 147 static void show_regwindow(struct pt_regs *regs)
 148 {
 149         struct reg_window __user *rw;
 150         struct reg_window *rwk;
 151         struct reg_window r_w;
 152         mm_segment_t old_fs;
 153
 154         if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
 155                 __asm__ __volatile__ ("flushw");
 156                 rw = (struct reg_window __user *)
 157                         (regs->u_regs[14] + STACK_BIAS);
 158                 rwk = (struct reg_window *)
 159                         (regs->u_regs[14] + STACK_BIAS);
 160                 if (!(regs->tstate & TSTATE_PRIV)) {
 161                         old_fs = get_fs();
 162                         set_fs (USER_DS);
 163                         if (copy_from_user (&r_w, rw, sizeof(r_w))) {
 164                                 set_fs (old_fs);
 165                                 return;
 166                         }
 167                         rwk = &r_w;
 168                         set_fs (old_fs);
 169                 }
 170         } else {
 171                 show_regwindow32(regs);
 172                 return;
 173         }
 174         printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
 175                rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
 176         printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
 177                rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
 178         printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
 179                rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
 180         printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
 181                rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
 182         if (regs->tstate & TSTATE_PRIV)
 183                 printk("I7: <%pS>\n", (void *) rwk->ins[7]);
 184 }
 185
 186 void show_regs(struct pt_regs *regs)
 187 {
 188         printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
 189                regs->tpc, regs->tnpc, regs->y, print_tainted());
 190         printk("TPC: <%pS>\n", (void *) regs->tpc);
 191         printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
 192                regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
 193                regs->u_regs[3]);
 194         printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
 195                regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
 196                regs->u_regs[7]);
 197         printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
 198                regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
 199                regs->u_regs[11]);
 200         printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
 201                regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
 202                regs->u_regs[15]);
 203         printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
 204         show_regwindow(regs);
 205         show_stack(current, (unsigned long *) regs->u_regs[UREG_FP]);
 206 }
 207
 208 struct global_reg_snapshot global_reg_snapshot[NR_CPUS];
 209 static DEFINE_SPINLOCK(global_reg_snapshot_lock);
 210
 211 static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
 212                               int this_cpu)
 213 {
 214         flushw_all();
 215
 216         global_reg_snapshot[this_cpu].tstate = regs->tstate;
 217         global_reg_snapshot[this_cpu].tpc = regs->tpc;
 218         global_reg_snapshot[this_cpu].tnpc = regs->tnpc;
 219         global_reg_snapshot[this_cpu].o7 = regs->u_regs[UREG_I7];
 220
 221         if (regs->tstate & TSTATE_PRIV) {
 222                 struct reg_window *rw;
 223
 224                 rw = (struct reg_window *)
 225                         (regs->u_regs[UREG_FP] + STACK_BIAS);
 226                 if (kstack_valid(tp, (unsigned long) rw)) {
 227                         global_reg_snapshot[this_cpu].i7 = rw->ins[7];
 228                         rw = (struct reg_window *)
 229                                 (rw->ins[6] + STACK_BIAS);
 230                         if (kstack_valid(tp, (unsigned long) rw))
 231                                 global_reg_snapshot[this_cpu].rpc = rw->ins[7];
 232                 }
 233         } else {
 234                 global_reg_snapshot[this_cpu].i7 = 0;
 235                 global_reg_snapshot[this_cpu].rpc = 0;
 236         }
 237         global_reg_snapshot[this_cpu].thread = tp;
 238 }
 239
 240 /* In order to avoid hangs we do not try to synchronize with the
 241  * global register dump client cpus.  The last store they make is to
 242  * the thread pointer, so do a short poll waiting for that to become
 243  * non-NULL.
 244  */
 245 static void __global_reg_poll(struct global_reg_snapshot *gp)
 246 {
 247         int limit = 0;
 248
 249         while (!gp->thread && ++limit < 100) {
 250                 barrier();
 251                 udelay(1);
 252         }
 253 }
 254
 255 void arch_trigger_all_cpu_backtrace(void)
 256 {
 257         struct thread_info *tp = current_thread_info();
 258         struct pt_regs *regs = get_irq_regs();
 259         unsigned long flags;
 260         int this_cpu, cpu;
 261
 262         if (!regs)
 263                 regs = tp->kregs;
 264
 265         spin_lock_irqsave(&global_reg_snapshot_lock, flags);
 266
 267         memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));
 268
 269         this_cpu = raw_smp_processor_id();
 270
 271         __global_reg_self(tp, regs, this_cpu);
 272
 273         smp_fetch_global_regs();
 274
 275         for_each_online_cpu(cpu) {
 276                 struct global_reg_snapshot *gp = &global_reg_snapshot[cpu];
 277
 278                 __global_reg_poll(gp);
 279
 280                 tp = gp->thread;
 281                 printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
 282                        (cpu == this_cpu ? '*' : ' '), cpu,
 283                        gp->tstate, gp->tpc, gp->tnpc,
 284                        ((tp && tp->task) ? tp->task->comm : "NULL"),
 285                        ((tp && tp->task) ? tp->task->pid : -1));
 286
 287                 if (gp->tstate & TSTATE_PRIV) {
 288                         printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
 289                                (void *) gp->tpc,
 290                                (void *) gp->o7,
 291                                (void *) gp->i7,
 292                                (void *) gp->rpc);
 293                 } else {
 294                         printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
 295                                gp->tpc, gp->o7, gp->i7, gp->rpc);
 296                 }
 297         }
 298
 299         memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));
 300
 301         spin_unlock_irqrestore(&global_reg_snapshot_lock, flags);
 302 }
 303
 304 #ifdef CONFIG_MAGIC_SYSRQ
 305
 306 static void sysrq_handle_globreg(int key)
 307 {
 308         arch_trigger_all_cpu_backtrace();
 309 }
 310
 311 static struct sysrq_key_op sparc_globalreg_op = {
 312         .handler        = sysrq_handle_globreg,
 313         .help_msg       = "Globalregs",
 314         .action_msg     = "Show Global CPU Regs",
 315 };
 316
 317 static int __init sparc_globreg_init(void)
 318 {
 319         return register_sysrq_key('y', &sparc_globalreg_op);
 320 }
 321
 322 core_initcall(sparc_globreg_init);
 323
 324 #endif
 325
 326 unsigned long thread_saved_pc(struct task_struct *tsk)
 327 {
 328         struct thread_info *ti = task_thread_info(tsk);
 329         unsigned long ret = 0xdeadbeefUL;
 330
 331         if (ti && ti->ksp) {
 332                 unsigned long *sp;
 333                 sp = (unsigned long *)(ti->ksp + STACK_BIAS);
 334                 if (((unsigned long)sp & (sizeof(long) - 1)) == 0UL &&
 335                     sp[14]) {
 336                         unsigned long *fp;
 337                         fp = (unsigned long *)(sp[14] + STACK_BIAS);
 338                         if (((unsigned long)fp & (sizeof(long) - 1)) == 0UL)
 339                                 ret = fp[15];
 340                 }
 341         }
 342         return ret;
 343 }
 344
 345 /* Free current thread data structures etc.. */
 346 void exit_thread(void)
 347 {
 348         struct thread_info *t = current_thread_info();
 349
 350         if (t->utraps) {
 351                 if (t->utraps[0] < 2)
 352                         kfree (t->utraps);
 353                 else
 354                         t->utraps[0]--;
 355         }
 356 }
 357
 358 void flush_thread(void)
 359 {
 360         struct thread_info *t = current_thread_info();
 361         struct mm_struct *mm;
 362
 363         mm = t->task->mm;
 364         if (mm)
 365                 tsb_context_switch(mm);
 366
 367         set_thread_wsaved(0);
 368
 369         /* Clear FPU register state. */
 370         t->fpsaved[0] = 0;
 371 }
 372
 373 /* It's a bit more tricky when 64-bit tasks are involved... */
 374 static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
 375 {
 376         unsigned long fp, distance, rval;
 377
 378         if (!(test_thread_flag(TIF_32BIT))) {
 379                 csp += STACK_BIAS;
 380                 psp += STACK_BIAS;
 381                 __get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
 382                 fp += STACK_BIAS;
 383         } else
 384                 __get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
 385
 386         /* Now align the stack as this is mandatory in the Sparc ABI
 387          * due to how register windows work.  This hides the
 388          * restriction from thread libraries etc.
 389          */
 390         csp &= ~15UL;
 391
 392         distance = fp - psp;
 393         rval = (csp - distance);
 394         if (copy_in_user((void __user *) rval, (void __user *) psp, distance))
 395                 rval = 0;
 396         else if (test_thread_flag(TIF_32BIT)) {
 397                 if (put_user(((u32)csp),
 398                              &(((struct reg_window32 __user *)rval)->ins[6])))
 399                         rval = 0;
 400         } else {
 401                 if (put_user(((u64)csp - STACK_BIAS),
 402                              &(((struct reg_window __user *)rval)->ins[6])))
 403                         rval = 0;
 404                 else
 405                         rval = rval - STACK_BIAS;
 406         }
 407
 408         return rval;
 409 }
 410
 411 /* Standard stuff. */
 412 static inline void shift_window_buffer(int first_win, int last_win,
 413                                        struct thread_info *t)
 414 {
 415         int i;
 416
 417         for (i = first_win; i < last_win; i++) {
 418                 t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
 419                 memcpy(&t->reg_window[i], &t->reg_window[i+1],
 420                        sizeof(struct reg_window));
 421         }
 422 }
 423
 424 void synchronize_user_stack(void)
 425 {
 426         struct thread_info *t = current_thread_info();
 427         unsigned long window;
 428
 429         flush_user_windows();
 430         if ((window = get_thread_wsaved()) != 0) {
 431                 int winsize = sizeof(struct reg_window);
 432                 int bias = 0;
 433
 434                 if (test_thread_flag(TIF_32BIT))
 435                         winsize = sizeof(struct reg_window32);
 436                 else
 437                         bias = STACK_BIAS;
 438
 439                 window -= 1;
 440                 do {
 441                         unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
 442                         struct reg_window *rwin = &t->reg_window[window];
 443
 444                         if (!copy_to_user((char __user *)sp, rwin, winsize)) {
 445                                 shift_window_buffer(window, get_thread_wsaved() - 1, t);
 446                                 set_thread_wsaved(get_thread_wsaved() - 1);
 447                         }
 448                 } while (window--);
 449         }
 450 }
 451
 452 static void stack_unaligned(unsigned long sp)
 453 {
 454         siginfo_t info;
 455
 456         info.si_signo = SIGBUS;
 457         info.si_errno = 0;
 458         info.si_code = BUS_ADRALN;
 459         info.si_addr = (void __user *) sp;
 460         info.si_trapno = 0;
 461         force_sig_info(SIGBUS, &info, current);
 462 }
 463
 464 void fault_in_user_windows(void)
 465 {
 466         struct thread_info *t = current_thread_info();
 467         unsigned long window;
 468         int winsize = sizeof(struct reg_window);
 469         int bias = 0;
 470
 471         if (test_thread_flag(TIF_32BIT))
 472                 winsize = sizeof(struct reg_window32);
 473         else
 474                 bias = STACK_BIAS;
 475
 476         flush_user_windows();
 477         window = get_thread_wsaved();
 478
 479         if (likely(window != 0)) {
 480                 window -= 1;
 481                 do {
 482                         unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
 483                         struct reg_window *rwin = &t->reg_window[window];
 484
 485                         if (unlikely(sp & 0x7UL))
 486                                 stack_unaligned(sp);
 487
 488                         if (unlikely(copy_to_user((char __user *)sp,
 489                                                   rwin, winsize)))
 490                                 goto barf;
 491                 } while (window--);
 492         }
 493         set_thread_wsaved(0);
 494         return;
 495
 496 barf:
 497         set_thread_wsaved(window + 1);
 498         do_exit(SIGILL);
 499 }
 500
 501 asmlinkage long sparc_do_fork(unsigned long clone_flags,
 502                               unsigned long stack_start,
 503                               struct pt_regs *regs,
 504                               unsigned long stack_size)
 505 {
 506         int __user *parent_tid_ptr, *child_tid_ptr;
 507         unsigned long orig_i1 = regs->u_regs[UREG_I1];
 508         long ret;
 509
 510 #ifdef CONFIG_COMPAT
 511         if (test_thread_flag(TIF_32BIT)) {
 512                 parent_tid_ptr = compat_ptr(regs->u_regs[UREG_I2]);
 513                 child_tid_ptr = compat_ptr(regs->u_regs[UREG_I4]);
 514         } else
 515 #endif
 516         {
 517                 parent_tid_ptr = (int __user *) regs->u_regs[UREG_I2];
 518                 child_tid_ptr = (int __user *) regs->u_regs[UREG_I4];
 519         }
 520
 521         ret = do_fork(clone_flags, stack_start,
 522                       regs, stack_size,
 523                       parent_tid_ptr, child_tid_ptr);
 524
 525         /* If we get an error and potentially restart the system
 526          * call, we're screwed because copy_thread() clobbered
 527          * the parent's %o1.  So detect that case and restore it
 528          * here.
 529          */
 530         if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 531                 regs->u_regs[UREG_I1] = orig_i1;
 532
 533         return ret;
 534 }
 535
 536 /* Copy a Sparc thread.  The fork() return value conventions
 537  * under SunOS are nothing short of bletcherous:
 538  * Parent -->  %o0 == childs  pid, %o1 == 0
 539  * Child  -->  %o0 == parents pid, %o1 == 1
 540  */
 541 int copy_thread(unsigned long clone_flags, unsigned long sp,
 542                 unsigned long unused,
 543                 struct task_struct *p, struct pt_regs *regs)
 544 {
 545         struct thread_info *t = task_thread_info(p);
 546         struct sparc_stackf *parent_sf;
 547         unsigned long child_stack_sz;
 548         char *child_trap_frame;
 549         int kernel_thread;
 550
 551         kernel_thread = (regs->tstate & TSTATE_PRIV) ? 1 : 0;
 552         parent_sf = ((struct sparc_stackf *) regs) - 1;
 553
 554         /* Calculate offset to stack_frame & pt_regs */
 555         child_stack_sz = ((STACKFRAME_SZ + TRACEREG_SZ) +
 556                           (kernel_thread ? STACKFRAME_SZ : 0));
 557         child_trap_frame = (task_stack_page(p) +
 558                             (THREAD_SIZE - child_stack_sz));
 559         memcpy(child_trap_frame, parent_sf, child_stack_sz);
 560
 561         t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) |
 562                                  (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
 563                 (((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
 564         t->new_child = 1;
 565         t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
 566         t->kregs = (struct pt_regs *) (child_trap_frame +
 567                                        sizeof(struct sparc_stackf));
 568         t->fpsaved[0] = 0;
 569
 570         if (kernel_thread) {
 571                 struct sparc_stackf *child_sf = (struct sparc_stackf *)
 572                         (child_trap_frame + (STACKFRAME_SZ + TRACEREG_SZ));
 573
 574                 /* Zero terminate the stack backtrace.  */
 575                 child_sf->fp = NULL;
 576                 t->kregs->u_regs[UREG_FP] =
 577                   ((unsigned long) child_sf) - STACK_BIAS;
 578
 579                 t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
 580                 t->kregs->u_regs[UREG_G6] = (unsigned long) t;
 581                 t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
 582         } else {
 583                 if (t->flags & _TIF_32BIT) {
 584                         sp &= 0x00000000ffffffffUL;
 585                         regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
 586                 }
 587                 t->kregs->u_regs[UREG_FP] = sp;
 588                 t->flags |= ((long)ASI_AIUS << TI_FLAG_CURRENT_DS_SHIFT);
 589                 if (sp != regs->u_regs[UREG_FP]) {
 590                         unsigned long csp;
 591
 592                         csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
 593                         if (!csp)
 594                                 return -EFAULT;
 595                         t->kregs->u_regs[UREG_FP] = csp;
 596                 }
 597                 if (t->utraps)
 598                         t->utraps[0]++;
 599         }
 600
 601         /* Set the return value for the child. */
 602         t->kregs->u_regs[UREG_I0] = current->pid;
 603         t->kregs->u_regs[UREG_I1] = 1;
 604
 605         /* Set the second return value for the parent. */
 606         regs->u_regs[UREG_I1] = 0;
 607
 608         if (clone_flags & CLONE_SETTLS)
 609                 t->kregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 610
 611         return 0;
 612 }
 613
 614 /*
 615  * This is the mechanism for creating a new kernel thread.
 616  *
 617  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 618  * who haven't done an "execve()") should use this: it will work within
 619  * a system call from a "real" process, but the process memory space will
 620  * not be freed until both the parent and the child have exited.
 621  */
 622 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 623 {
 624         long retval;
 625
 626         /* If the parent runs before fn(arg) is called by the child,
 627          * the input registers of this function can be clobbered.
 628          * So we stash 'fn' and 'arg' into global registers which
 629          * will not be modified by the parent.
 630          */
 631         __asm__ __volatile__("mov %4, %%g2\n\t"    /* Save FN into global */
 632                              "mov %5, %%g3\n\t"    /* Save ARG into global */
 633                              "mov %1, %%g1\n\t"    /* Clone syscall nr. */
 634                              "mov %2, %%o0\n\t"    /* Clone flags. */
 635                              "mov 0, %%o1\n\t"     /* usp arg == 0 */
 636                              "t 0x6d\n\t"          /* Linux/Sparc clone(). */
 637                              "brz,a,pn %%o1, 1f\n\t" /* Parent, just return. */
 638                              " mov %%o0, %0\n\t"
 639                              "jmpl %%g2, %%o7\n\t"   /* Call the function. */
 640                              " mov %%g3, %%o0\n\t"   /* Set arg in delay. */
 641                              "mov %3, %%g1\n\t"
 642                              "t 0x6d\n\t"          /* Linux/Sparc exit(). */
 643                              /* Notreached by child. */
 644                              "1:" :
 645                              "=r" (retval) :
 646                              "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
 647                              "i" (__NR_exit),  "r" (fn), "r" (arg) :
 648                              "g1", "g2", "g3", "o0", "o1", "memory", "cc");
 649         return retval;
 650 }
 651 EXPORT_SYMBOL(kernel_thread);
 652
 653 typedef struct {
 654         union {
 655                 unsigned int    pr_regs[32];
 656                 unsigned long   pr_dregs[16];
 657         } pr_fr;
 658         unsigned int __unused;
 659         unsigned int    pr_fsr;
 660         unsigned char   pr_qcnt;
 661         unsigned char   pr_q_entrysize;
 662         unsigned char   pr_en;
 663         unsigned int    pr_q[64];
 664 } elf_fpregset_t32;
 665
 666 /*
 667  * fill in the fpu structure for a core dump.
 668  */
 669 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 670 {
 671         unsigned long *kfpregs = current_thread_info()->fpregs;
 672         unsigned long fprs = current_thread_info()->fpsaved[0];
 673
 674         if (test_thread_flag(TIF_32BIT)) {
 675                 elf_fpregset_t32 *fpregs32 = (elf_fpregset_t32 *)fpregs;
 676
 677                 if (fprs & FPRS_DL)
 678                         memcpy(&fpregs32->pr_fr.pr_regs[0], kfpregs,
 679                                sizeof(unsigned int) * 32);
 680                 else
 681                         memset(&fpregs32->pr_fr.pr_regs[0], 0,
 682                                sizeof(unsigned int) * 32);
 683                 fpregs32->pr_qcnt = 0;
 684                 fpregs32->pr_q_entrysize = 8;
 685                 memset(&fpregs32->pr_q[0], 0,
 686                        (sizeof(unsigned int) * 64));
 687                 if (fprs & FPRS_FEF) {
 688                         fpregs32->pr_fsr = (unsigned int) current_thread_info()->xfsr[0];
 689                         fpregs32->pr_en = 1;
 690                 } else {
 691                         fpregs32->pr_fsr = 0;
 692                         fpregs32->pr_en = 0;
 693                 }
 694         } else {
 695                 if(fprs & FPRS_DL)
 696                         memcpy(&fpregs->pr_regs[0], kfpregs,
 697                                sizeof(unsigned int) * 32);
 698                 else
 699                         memset(&fpregs->pr_regs[0], 0,
 700                                sizeof(unsigned int) * 32);
 701                 if(fprs & FPRS_DU)
 702                         memcpy(&fpregs->pr_regs[16], kfpregs+16,
 703                                sizeof(unsigned int) * 32);
 704                 else
 705                         memset(&fpregs->pr_regs[16], 0,
 706                                sizeof(unsigned int) * 32);
 707                 if(fprs & FPRS_FEF) {
 708                         fpregs->pr_fsr = current_thread_info()->xfsr[0];
 709                         fpregs->pr_gsr = current_thread_info()->gsr[0];
 710                 } else {
 711                         fpregs->pr_fsr = fpregs->pr_gsr = 0;
 712                 }
 713                 fpregs->pr_fprs = fprs;
 714         }
 715         return 1;
 716 }
 717 EXPORT_SYMBOL(dump_fpu);
 718
 719 /*
 720  * sparc_execve() executes a new program after the asm stub has set
 721  * things up for us.  This should basically do what I want it to.
 722  */
 723 asmlinkage int sparc_execve(struct pt_regs *regs)
 724 {
 725         int error, base = 0;
 726         char *filename;
 727
 728         /* User register window flush is done by entry.S */
 729
 730         /* Check for indirect call. */
 731         if (regs->u_regs[UREG_G1] == 0)
 732                 base = 1;
 733
 734         filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
 735         error = PTR_ERR(filename);
 736         if (IS_ERR(filename))
 737                 goto out;
 738         error = do_execve(filename,
 739                           (const char __user *const __user *)
 740                           regs->u_regs[base + UREG_I1],
 741                           (const char __user *const __user *)
 742                           regs->u_regs[base + UREG_I2], regs);
 743         putname(filename);
 744         if (!error) {
 745                 fprs_write(0);
 746                 current_thread_info()->xfsr[0] = 0;
 747                 current_thread_info()->fpsaved[0] = 0;
 748                 regs->tstate &= ~TSTATE_PEF;
 749         }
 750 out:
 751         return error;
 752 }
 753
 754 unsigned long get_wchan(struct task_struct *task)
 755 {
 756         unsigned long pc, fp, bias = 0;
 757         struct thread_info *tp;
 758         struct reg_window *rw;
 759         unsigned long ret = 0;
 760         int count = 0;
 761
 762         if (!task || task == current ||
 763             task->state == TASK_RUNNING)
 764                 goto out;
 765
 766         tp = task_thread_info(task);
 767         bias = STACK_BIAS;
 768         fp = task_thread_info(task)->ksp + bias;
 769
 770         do {
 771                 if (!kstack_valid(tp, fp))
 772                         break;
 773                 rw = (struct reg_window *) fp;
 774                 pc = rw->ins[7];
 775                 if (!in_sched_functions(pc)) {
 776                         ret = pc;
 777                         goto out;
 778                 }
 779                 fp = rw->ins[6] + bias;
 780         } while (++count < 16);
 781
 782 out:
 783         return ret;
 784 }