linux/arch/sparc/kernel/process.c
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   1/*  linux/arch/sparc/kernel/process.c
   2 *
   3 *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
   4 *  Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be)
   5 */
   6
   7/*
   8 * This file handles the architecture-dependent parts of process handling..
   9 */
  10
  11#include <stdarg.h>
  12
  13#include <linux/errno.h>
  14#include <linux/module.h>
  15#include <linux/sched.h>
  16#include <linux/kernel.h>
  17#include <linux/mm.h>
  18#include <linux/stddef.h>
  19#include <linux/ptrace.h>
  20#include <linux/slab.h>
  21#include <linux/user.h>
  22#include <linux/smp.h>
  23#include <linux/reboot.h>
  24#include <linux/delay.h>
  25#include <linux/pm.h>
  26#include <linux/init.h>
  27
  28#include <asm/auxio.h>
  29#include <asm/oplib.h>
  30#include <asm/uaccess.h>
  31#include <asm/system.h>
  32#include <asm/page.h>
  33#include <asm/pgalloc.h>
  34#include <asm/pgtable.h>
  35#include <asm/delay.h>
  36#include <asm/processor.h>
  37#include <asm/psr.h>
  38#include <asm/elf.h>
  39#include <asm/prom.h>
  40#include <asm/unistd.h>
  41
  42/* 
  43 * Power management idle function 
  44 * Set in pm platform drivers (apc.c and pmc.c)
  45 */
  46void (*pm_idle)(void);
  47
  48/* 
  49 * Power-off handler instantiation for pm.h compliance
  50 * This is done via auxio, but could be used as a fallback
  51 * handler when auxio is not present-- unused for now...
  52 */
  53void (*pm_power_off)(void) = machine_power_off;
  54EXPORT_SYMBOL(pm_power_off);
  55
  56/*
  57 * sysctl - toggle power-off restriction for serial console 
  58 * systems in machine_power_off()
  59 */
  60int scons_pwroff = 1;
  61
  62extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
  63
  64struct task_struct *last_task_used_math = NULL;
  65struct thread_info *current_set[NR_CPUS];
  66
  67#ifndef CONFIG_SMP
  68
  69#define SUN4C_FAULT_HIGH 100
  70
  71/*
  72 * the idle loop on a Sparc... ;)
  73 */
  74void cpu_idle(void)
  75{
  76        /* endless idle loop with no priority at all */
  77        for (;;) {
  78                if (ARCH_SUN4C_SUN4) {
  79                        static int count = HZ;
  80                        static unsigned long last_jiffies;
  81                        static unsigned long last_faults;
  82                        static unsigned long fps;
  83                        unsigned long now;
  84                        unsigned long faults;
  85
  86                        extern unsigned long sun4c_kernel_faults;
  87                        extern void sun4c_grow_kernel_ring(void);
  88
  89                        local_irq_disable();
  90                        now = jiffies;
  91                        count -= (now - last_jiffies);
  92                        last_jiffies = now;
  93                        if (count < 0) {
  94                                count += HZ;
  95                                faults = sun4c_kernel_faults;
  96                                fps = (fps + (faults - last_faults)) >> 1;
  97                                last_faults = faults;
  98#if 0
  99                                printk("kernel faults / second = %ld\n", fps);
 100#endif
 101                                if (fps >= SUN4C_FAULT_HIGH) {
 102                                        sun4c_grow_kernel_ring();
 103                                }
 104                        }
 105                        local_irq_enable();
 106                }
 107
 108                if (pm_idle) {
 109                        while (!need_resched())
 110                                (*pm_idle)();
 111                } else {
 112                        while (!need_resched())
 113                                cpu_relax();
 114                }
 115                preempt_enable_no_resched();
 116                schedule();
 117                preempt_disable();
 118                check_pgt_cache();
 119        }
 120}
 121
 122#else
 123
 124/* This is being executed in task 0 'user space'. */
 125void cpu_idle(void)
 126{
 127        set_thread_flag(TIF_POLLING_NRFLAG);
 128        /* endless idle loop with no priority at all */
 129        while(1) {
 130                while (!need_resched())
 131                        cpu_relax();
 132                preempt_enable_no_resched();
 133                schedule();
 134                preempt_disable();
 135                check_pgt_cache();
 136        }
 137}
 138
 139#endif
 140
 141/* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
 142void machine_halt(void)
 143{
 144        local_irq_enable();
 145        mdelay(8);
 146        local_irq_disable();
 147        prom_halt();
 148        panic("Halt failed!");
 149}
 150
 151void machine_restart(char * cmd)
 152{
 153        char *p;
 154        
 155        local_irq_enable();
 156        mdelay(8);
 157        local_irq_disable();
 158
 159        p = strchr (reboot_command, '\n');
 160        if (p) *p = 0;
 161        if (cmd)
 162                prom_reboot(cmd);
 163        if (*reboot_command)
 164                prom_reboot(reboot_command);
 165        prom_feval ("reset");
 166        panic("Reboot failed!");
 167}
 168
 169void machine_power_off(void)
 170{
 171#ifdef CONFIG_SUN_AUXIO
 172        if (auxio_power_register &&
 173            (strcmp(of_console_device->type, "serial") || scons_pwroff))
 174                *auxio_power_register |= AUXIO_POWER_OFF;
 175#endif
 176        machine_halt();
 177}
 178
 179#if 0
 180
 181static DEFINE_SPINLOCK(sparc_backtrace_lock);
 182
 183void __show_backtrace(unsigned long fp)
 184{
 185        struct reg_window *rw;
 186        unsigned long flags;
 187        int cpu = smp_processor_id();
 188
 189        spin_lock_irqsave(&sparc_backtrace_lock, flags);
 190
 191        rw = (struct reg_window *)fp;
 192        while(rw && (((unsigned long) rw) >= PAGE_OFFSET) &&
 193            !(((unsigned long) rw) & 0x7)) {
 194                printk("CPU[%d]: ARGS[%08lx,%08lx,%08lx,%08lx,%08lx,%08lx] "
 195                       "FP[%08lx] CALLER[%08lx]: ", cpu,
 196                       rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 197                       rw->ins[4], rw->ins[5],
 198                       rw->ins[6],
 199                       rw->ins[7]);
 200                printk("%pS\n", (void *) rw->ins[7]);
 201                rw = (struct reg_window *) rw->ins[6];
 202        }
 203        spin_unlock_irqrestore(&sparc_backtrace_lock, flags);
 204}
 205
 206#define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
 207#define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
 208#define __GET_FP(fp) __asm__ __volatile__("mov %%i6, %0" : "=r" (fp))
 209
 210void show_backtrace(void)
 211{
 212        unsigned long fp;
 213
 214        __SAVE; __SAVE; __SAVE; __SAVE;
 215        __SAVE; __SAVE; __SAVE; __SAVE;
 216        __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 217        __RESTORE; __RESTORE; __RESTORE; __RESTORE;
 218
 219        __GET_FP(fp);
 220
 221        __show_backtrace(fp);
 222}
 223
 224#ifdef CONFIG_SMP
 225void smp_show_backtrace_all_cpus(void)
 226{
 227        xc0((smpfunc_t) show_backtrace);
 228        show_backtrace();
 229}
 230#endif
 231
 232void show_stackframe(struct sparc_stackf *sf)
 233{
 234        unsigned long size;
 235        unsigned long *stk;
 236        int i;
 237
 238        printk("l0: %08lx l1: %08lx l2: %08lx l3: %08lx "
 239               "l4: %08lx l5: %08lx l6: %08lx l7: %08lx\n",
 240               sf->locals[0], sf->locals[1], sf->locals[2], sf->locals[3],
 241               sf->locals[4], sf->locals[5], sf->locals[6], sf->locals[7]);
 242        printk("i0: %08lx i1: %08lx i2: %08lx i3: %08lx "
 243               "i4: %08lx i5: %08lx fp: %08lx i7: %08lx\n",
 244               sf->ins[0], sf->ins[1], sf->ins[2], sf->ins[3],
 245               sf->ins[4], sf->ins[5], (unsigned long)sf->fp, sf->callers_pc);
 246        printk("sp: %08lx x0: %08lx x1: %08lx x2: %08lx "
 247               "x3: %08lx x4: %08lx x5: %08lx xx: %08lx\n",
 248               (unsigned long)sf->structptr, sf->xargs[0], sf->xargs[1],
 249               sf->xargs[2], sf->xargs[3], sf->xargs[4], sf->xargs[5],
 250               sf->xxargs[0]);
 251        size = ((unsigned long)sf->fp) - ((unsigned long)sf);
 252        size -= STACKFRAME_SZ;
 253        stk = (unsigned long *)((unsigned long)sf + STACKFRAME_SZ);
 254        i = 0;
 255        do {
 256                printk("s%d: %08lx\n", i++, *stk++);
 257        } while ((size -= sizeof(unsigned long)));
 258}
 259#endif
 260
 261void show_regs(struct pt_regs *r)
 262{
 263        struct reg_window *rw = (struct reg_window *) r->u_regs[14];
 264
 265        printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
 266               r->psr, r->pc, r->npc, r->y, print_tainted());
 267        printk("PC: <%pS>\n", (void *) r->pc);
 268        printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 269               r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
 270               r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
 271        printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 272               r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
 273               r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
 274        printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
 275
 276        printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 277               rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
 278               rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
 279        printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 280               rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 281               rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
 282}
 283
 284/*
 285 * The show_stack is an external API which we do not use ourselves.
 286 * The oops is printed in die_if_kernel.
 287 */
 288void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 289{
 290        unsigned long pc, fp;
 291        unsigned long task_base;
 292        struct reg_window *rw;
 293        int count = 0;
 294
 295        if (tsk != NULL)
 296                task_base = (unsigned long) task_stack_page(tsk);
 297        else
 298                task_base = (unsigned long) current_thread_info();
 299
 300        fp = (unsigned long) _ksp;
 301        do {
 302                /* Bogus frame pointer? */
 303                if (fp < (task_base + sizeof(struct thread_info)) ||
 304                    fp >= (task_base + (PAGE_SIZE << 1)))
 305                        break;
 306                rw = (struct reg_window *) fp;
 307                pc = rw->ins[7];
 308                printk("[%08lx : ", pc);
 309                printk("%pS ] ", (void *) pc);
 310                fp = rw->ins[6];
 311        } while (++count < 16);
 312        printk("\n");
 313}
 314
 315void dump_stack(void)
 316{
 317        unsigned long *ksp;
 318
 319        __asm__ __volatile__("mov       %%fp, %0"
 320                             : "=r" (ksp));
 321        show_stack(current, ksp);
 322}
 323
 324EXPORT_SYMBOL(dump_stack);
 325
 326/*
 327 * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
 328 */
 329unsigned long thread_saved_pc(struct task_struct *tsk)
 330{
 331        return task_thread_info(tsk)->kpc;
 332}
 333
 334/*
 335 * Free current thread data structures etc..
 336 */
 337void exit_thread(void)
 338{
 339#ifndef CONFIG_SMP
 340        if(last_task_used_math == current) {
 341#else
 342        if (test_thread_flag(TIF_USEDFPU)) {
 343#endif
 344                /* Keep process from leaving FPU in a bogon state. */
 345                put_psr(get_psr() | PSR_EF);
 346                fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 347                       &current->thread.fpqueue[0], &current->thread.fpqdepth);
 348#ifndef CONFIG_SMP
 349                last_task_used_math = NULL;
 350#else
 351                clear_thread_flag(TIF_USEDFPU);
 352#endif
 353        }
 354}
 355
 356void flush_thread(void)
 357{
 358        current_thread_info()->w_saved = 0;
 359
 360#ifndef CONFIG_SMP
 361        if(last_task_used_math == current) {
 362#else
 363        if (test_thread_flag(TIF_USEDFPU)) {
 364#endif
 365                /* Clean the fpu. */
 366                put_psr(get_psr() | PSR_EF);
 367                fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 368                       &current->thread.fpqueue[0], &current->thread.fpqdepth);
 369#ifndef CONFIG_SMP
 370                last_task_used_math = NULL;
 371#else
 372                clear_thread_flag(TIF_USEDFPU);
 373#endif
 374        }
 375
 376        /* Now, this task is no longer a kernel thread. */
 377        current->thread.current_ds = USER_DS;
 378        if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 379                current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 380
 381                /* We must fixup kregs as well. */
 382                /* XXX This was not fixed for ti for a while, worked. Unused? */
 383                current->thread.kregs = (struct pt_regs *)
 384                    (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 385        }
 386}
 387
 388static inline struct sparc_stackf __user *
 389clone_stackframe(struct sparc_stackf __user *dst,
 390                 struct sparc_stackf __user *src)
 391{
 392        unsigned long size, fp;
 393        struct sparc_stackf *tmp;
 394        struct sparc_stackf __user *sp;
 395
 396        if (get_user(tmp, &src->fp))
 397                return NULL;
 398
 399        fp = (unsigned long) tmp;
 400        size = (fp - ((unsigned long) src));
 401        fp = (unsigned long) dst;
 402        sp = (struct sparc_stackf __user *)(fp - size); 
 403
 404        /* do_fork() grabs the parent semaphore, we must release it
 405         * temporarily so we can build the child clone stack frame
 406         * without deadlocking.
 407         */
 408        if (__copy_user(sp, src, size))
 409                sp = NULL;
 410        else if (put_user(fp, &sp->fp))
 411                sp = NULL;
 412
 413        return sp;
 414}
 415
 416asmlinkage int sparc_do_fork(unsigned long clone_flags,
 417                             unsigned long stack_start,
 418                             struct pt_regs *regs,
 419                             unsigned long stack_size)
 420{
 421        unsigned long parent_tid_ptr, child_tid_ptr;
 422        unsigned long orig_i1 = regs->u_regs[UREG_I1];
 423        long ret;
 424
 425        parent_tid_ptr = regs->u_regs[UREG_I2];
 426        child_tid_ptr = regs->u_regs[UREG_I4];
 427
 428        ret = do_fork(clone_flags, stack_start,
 429                      regs, stack_size,
 430                      (int __user *) parent_tid_ptr,
 431                      (int __user *) child_tid_ptr);
 432
 433        /* If we get an error and potentially restart the system
 434         * call, we're screwed because copy_thread() clobbered
 435         * the parent's %o1.  So detect that case and restore it
 436         * here.
 437         */
 438        if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 439                regs->u_regs[UREG_I1] = orig_i1;
 440
 441        return ret;
 442}
 443
 444/* Copy a Sparc thread.  The fork() return value conventions
 445 * under SunOS are nothing short of bletcherous:
 446 * Parent -->  %o0 == childs  pid, %o1 == 0
 447 * Child  -->  %o0 == parents pid, %o1 == 1
 448 *
 449 * NOTE: We have a separate fork kpsr/kwim because
 450 *       the parent could change these values between
 451 *       sys_fork invocation and when we reach here
 452 *       if the parent should sleep while trying to
 453 *       allocate the task_struct and kernel stack in
 454 *       do_fork().
 455 * XXX See comment above sys_vfork in sparc64. todo.
 456 */
 457extern void ret_from_fork(void);
 458
 459int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 460                unsigned long unused,
 461                struct task_struct *p, struct pt_regs *regs)
 462{
 463        struct thread_info *ti = task_thread_info(p);
 464        struct pt_regs *childregs;
 465        char *new_stack;
 466
 467#ifndef CONFIG_SMP
 468        if(last_task_used_math == current) {
 469#else
 470        if (test_thread_flag(TIF_USEDFPU)) {
 471#endif
 472                put_psr(get_psr() | PSR_EF);
 473                fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 474                       &p->thread.fpqueue[0], &p->thread.fpqdepth);
 475#ifdef CONFIG_SMP
 476                clear_thread_flag(TIF_USEDFPU);
 477#endif
 478        }
 479
 480        /*
 481         *  p->thread_info         new_stack   childregs
 482         *  !                      !           !             {if(PSR_PS) }
 483         *  V                      V (stk.fr.) V  (pt_regs)  { (stk.fr.) }
 484         *  +----- - - - - - ------+===========+============={+==========}+
 485         */
 486        new_stack = task_stack_page(p) + THREAD_SIZE;
 487        if (regs->psr & PSR_PS)
 488                new_stack -= STACKFRAME_SZ;
 489        new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 490        memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 491        childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 492
 493        /*
 494         * A new process must start with interrupts closed in 2.5,
 495         * because this is how Mingo's scheduler works (see schedule_tail
 496         * and finish_arch_switch). If we do not do it, a timer interrupt hits
 497         * before we unlock, attempts to re-take the rq->lock, and then we die.
 498         * Thus, kpsr|=PSR_PIL.
 499         */
 500        ti->ksp = (unsigned long) new_stack;
 501        ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 502        ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 503        ti->kwim = current->thread.fork_kwim;
 504
 505        if(regs->psr & PSR_PS) {
 506                extern struct pt_regs fake_swapper_regs;
 507
 508                p->thread.kregs = &fake_swapper_regs;
 509                new_stack += STACKFRAME_SZ + TRACEREG_SZ;
 510                childregs->u_regs[UREG_FP] = (unsigned long) new_stack;
 511                p->thread.flags |= SPARC_FLAG_KTHREAD;
 512                p->thread.current_ds = KERNEL_DS;
 513                memcpy(new_stack, (void *)regs->u_regs[UREG_FP], STACKFRAME_SZ);
 514                childregs->u_regs[UREG_G6] = (unsigned long) ti;
 515        } else {
 516                p->thread.kregs = childregs;
 517                childregs->u_regs[UREG_FP] = sp;
 518                p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 519                p->thread.current_ds = USER_DS;
 520
 521                if (sp != regs->u_regs[UREG_FP]) {
 522                        struct sparc_stackf __user *childstack;
 523                        struct sparc_stackf __user *parentstack;
 524
 525                        /*
 526                         * This is a clone() call with supplied user stack.
 527                         * Set some valid stack frames to give to the child.
 528                         */
 529                        childstack = (struct sparc_stackf __user *)
 530                                (sp & ~0x7UL);
 531                        parentstack = (struct sparc_stackf __user *)
 532                                regs->u_regs[UREG_FP];
 533
 534#if 0
 535                        printk("clone: parent stack:\n");
 536                        show_stackframe(parentstack);
 537#endif
 538
 539                        childstack = clone_stackframe(childstack, parentstack);
 540                        if (!childstack)
 541                                return -EFAULT;
 542
 543#if 0
 544                        printk("clone: child stack:\n");
 545                        show_stackframe(childstack);
 546#endif
 547
 548                        childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 549                }
 550        }
 551
 552#ifdef CONFIG_SMP
 553        /* FPU must be disabled on SMP. */
 554        childregs->psr &= ~PSR_EF;
 555#endif
 556
 557        /* Set the return value for the child. */
 558        childregs->u_regs[UREG_I0] = current->pid;
 559        childregs->u_regs[UREG_I1] = 1;
 560
 561        /* Set the return value for the parent. */
 562        regs->u_regs[UREG_I1] = 0;
 563
 564        if (clone_flags & CLONE_SETTLS)
 565                childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 566
 567        return 0;
 568}
 569
 570/*
 571 * fill in the fpu structure for a core dump.
 572 */
 573int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 574{
 575        if (used_math()) {
 576                memset(fpregs, 0, sizeof(*fpregs));
 577                fpregs->pr_q_entrysize = 8;
 578                return 1;
 579        }
 580#ifdef CONFIG_SMP
 581        if (test_thread_flag(TIF_USEDFPU)) {
 582                put_psr(get_psr() | PSR_EF);
 583                fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 584                       &current->thread.fpqueue[0], &current->thread.fpqdepth);
 585                if (regs != NULL) {
 586                        regs->psr &= ~(PSR_EF);
 587                        clear_thread_flag(TIF_USEDFPU);
 588                }
 589        }
 590#else
 591        if (current == last_task_used_math) {
 592                put_psr(get_psr() | PSR_EF);
 593                fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 594                       &current->thread.fpqueue[0], &current->thread.fpqdepth);
 595                if (regs != NULL) {
 596                        regs->psr &= ~(PSR_EF);
 597                        last_task_used_math = NULL;
 598                }
 599        }
 600#endif
 601        memcpy(&fpregs->pr_fr.pr_regs[0],
 602               &current->thread.float_regs[0],
 603               (sizeof(unsigned long) * 32));
 604        fpregs->pr_fsr = current->thread.fsr;
 605        fpregs->pr_qcnt = current->thread.fpqdepth;
 606        fpregs->pr_q_entrysize = 8;
 607        fpregs->pr_en = 1;
 608        if(fpregs->pr_qcnt != 0) {
 609                memcpy(&fpregs->pr_q[0],
 610                       &current->thread.fpqueue[0],
 611                       sizeof(struct fpq) * fpregs->pr_qcnt);
 612        }
 613        /* Zero out the rest. */
 614        memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 615               sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 616        return 1;
 617}
 618
 619/*
 620 * sparc_execve() executes a new program after the asm stub has set
 621 * things up for us.  This should basically do what I want it to.
 622 */
 623asmlinkage int sparc_execve(struct pt_regs *regs)
 624{
 625        int error, base = 0;
 626        char *filename;
 627
 628        /* Check for indirect call. */
 629        if(regs->u_regs[UREG_G1] == 0)
 630                base = 1;
 631
 632        filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
 633        error = PTR_ERR(filename);
 634        if(IS_ERR(filename))
 635                goto out;
 636        error = do_execve(filename,
 637                          (char __user * __user *)regs->u_regs[base + UREG_I1],
 638                          (char __user * __user *)regs->u_regs[base + UREG_I2],
 639                          regs);
 640        putname(filename);
 641out:
 642        return error;
 643}
 644
 645/*
 646 * This is the mechanism for creating a new kernel thread.
 647 *
 648 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 649 * who haven't done an "execve()") should use this: it will work within
 650 * a system call from a "real" process, but the process memory space will
 651 * not be freed until both the parent and the child have exited.
 652 */
 653pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 654{
 655        long retval;
 656
 657        __asm__ __volatile__("mov %4, %%g2\n\t"    /* Set aside fn ptr... */
 658                             "mov %5, %%g3\n\t"    /* and arg. */
 659                             "mov %1, %%g1\n\t"
 660                             "mov %2, %%o0\n\t"    /* Clone flags. */
 661                             "mov 0, %%o1\n\t"     /* usp arg == 0 */
 662                             "t 0x10\n\t"          /* Linux/Sparc clone(). */
 663                             "cmp %%o1, 0\n\t"
 664                             "be 1f\n\t"           /* The parent, just return. */
 665                             " nop\n\t"            /* Delay slot. */
 666                             "jmpl %%g2, %%o7\n\t" /* Call the function. */
 667                             " mov %%g3, %%o0\n\t" /* Get back the arg in delay. */
 668                             "mov %3, %%g1\n\t"
 669                             "t 0x10\n\t"          /* Linux/Sparc exit(). */
 670                             /* Notreached by child. */
 671                             "1: mov %%o0, %0\n\t" :
 672                             "=r" (retval) :
 673                             "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
 674                             "i" (__NR_exit),  "r" (fn), "r" (arg) :
 675                             "g1", "g2", "g3", "o0", "o1", "memory", "cc");
 676        return retval;
 677}
 678
 679unsigned long get_wchan(struct task_struct *task)
 680{
 681        unsigned long pc, fp, bias = 0;
 682        unsigned long task_base = (unsigned long) task;
 683        unsigned long ret = 0;
 684        struct reg_window *rw;
 685        int count = 0;
 686
 687        if (!task || task == current ||
 688            task->state == TASK_RUNNING)
 689                goto out;
 690
 691        fp = task_thread_info(task)->ksp + bias;
 692        do {
 693                /* Bogus frame pointer? */
 694                if (fp < (task_base + sizeof(struct thread_info)) ||
 695                    fp >= (task_base + (2 * PAGE_SIZE)))
 696                        break;
 697                rw = (struct reg_window *) fp;
 698                pc = rw->ins[7];
 699                if (!in_sched_functions(pc)) {
 700                        ret = pc;
 701                        goto out;
 702                }
 703                fp = rw->ins[6] + bias;
 704        } while (++count < 16);
 705
 706out:
 707        return ret;
 708}
 709
 710