sparc: TIF_ABI_PENDING bit removal
[~shefty/rdma-dev.git] / 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 }
206
207 struct global_reg_snapshot global_reg_snapshot[NR_CPUS];
208 static DEFINE_SPINLOCK(global_reg_snapshot_lock);
209
210 static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
211                               int this_cpu)
212 {
213         flushw_all();
214
215         global_reg_snapshot[this_cpu].tstate = regs->tstate;
216         global_reg_snapshot[this_cpu].tpc = regs->tpc;
217         global_reg_snapshot[this_cpu].tnpc = regs->tnpc;
218         global_reg_snapshot[this_cpu].o7 = regs->u_regs[UREG_I7];
219
220         if (regs->tstate & TSTATE_PRIV) {
221                 struct reg_window *rw;
222
223                 rw = (struct reg_window *)
224                         (regs->u_regs[UREG_FP] + STACK_BIAS);
225                 if (kstack_valid(tp, (unsigned long) rw)) {
226                         global_reg_snapshot[this_cpu].i7 = rw->ins[7];
227                         rw = (struct reg_window *)
228                                 (rw->ins[6] + STACK_BIAS);
229                         if (kstack_valid(tp, (unsigned long) rw))
230                                 global_reg_snapshot[this_cpu].rpc = rw->ins[7];
231                 }
232         } else {
233                 global_reg_snapshot[this_cpu].i7 = 0;
234                 global_reg_snapshot[this_cpu].rpc = 0;
235         }
236         global_reg_snapshot[this_cpu].thread = tp;
237 }
238
239 /* In order to avoid hangs we do not try to synchronize with the
240  * global register dump client cpus.  The last store they make is to
241  * the thread pointer, so do a short poll waiting for that to become
242  * non-NULL.
243  */
244 static void __global_reg_poll(struct global_reg_snapshot *gp)
245 {
246         int limit = 0;
247
248         while (!gp->thread && ++limit < 100) {
249                 barrier();
250                 udelay(1);
251         }
252 }
253
254 void arch_trigger_all_cpu_backtrace(void)
255 {
256         struct thread_info *tp = current_thread_info();
257         struct pt_regs *regs = get_irq_regs();
258         unsigned long flags;
259         int this_cpu, cpu;
260
261         if (!regs)
262                 regs = tp->kregs;
263
264         spin_lock_irqsave(&global_reg_snapshot_lock, flags);
265
266         memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));
267
268         this_cpu = raw_smp_processor_id();
269
270         __global_reg_self(tp, regs, this_cpu);
271
272         smp_fetch_global_regs();
273
274         for_each_online_cpu(cpu) {
275                 struct global_reg_snapshot *gp = &global_reg_snapshot[cpu];
276
277                 __global_reg_poll(gp);
278
279                 tp = gp->thread;
280                 printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
281                        (cpu == this_cpu ? '*' : ' '), cpu,
282                        gp->tstate, gp->tpc, gp->tnpc,
283                        ((tp && tp->task) ? tp->task->comm : "NULL"),
284                        ((tp && tp->task) ? tp->task->pid : -1));
285
286                 if (gp->tstate & TSTATE_PRIV) {
287                         printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
288                                (void *) gp->tpc,
289                                (void *) gp->o7,
290                                (void *) gp->i7,
291                                (void *) gp->rpc);
292                 } else {
293                         printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
294                                gp->tpc, gp->o7, gp->i7, gp->rpc);
295                 }
296         }
297
298         memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));
299
300         spin_unlock_irqrestore(&global_reg_snapshot_lock, flags);
301 }
302
303 #ifdef CONFIG_MAGIC_SYSRQ
304
305 static void sysrq_handle_globreg(int key, struct tty_struct *tty)
306 {
307         arch_trigger_all_cpu_backtrace();
308 }
309
310 static struct sysrq_key_op sparc_globalreg_op = {
311         .handler        = sysrq_handle_globreg,
312         .help_msg       = "Globalregs",
313         .action_msg     = "Show Global CPU Regs",
314 };
315
316 static int __init sparc_globreg_init(void)
317 {
318         return register_sysrq_key('y', &sparc_globalreg_op);
319 }
320
321 core_initcall(sparc_globreg_init);
322
323 #endif
324
325 unsigned long thread_saved_pc(struct task_struct *tsk)
326 {
327         struct thread_info *ti = task_thread_info(tsk);
328         unsigned long ret = 0xdeadbeefUL;
329         
330         if (ti && ti->ksp) {
331                 unsigned long *sp;
332                 sp = (unsigned long *)(ti->ksp + STACK_BIAS);
333                 if (((unsigned long)sp & (sizeof(long) - 1)) == 0UL &&
334                     sp[14]) {
335                         unsigned long *fp;
336                         fp = (unsigned long *)(sp[14] + STACK_BIAS);
337                         if (((unsigned long)fp & (sizeof(long) - 1)) == 0UL)
338                                 ret = fp[15];
339                 }
340         }
341         return ret;
342 }
343
344 /* Free current thread data structures etc.. */
345 void exit_thread(void)
346 {
347         struct thread_info *t = current_thread_info();
348
349         if (t->utraps) {
350                 if (t->utraps[0] < 2)
351                         kfree (t->utraps);
352                 else
353                         t->utraps[0]--;
354         }
355
356         if (test_and_clear_thread_flag(TIF_PERFCTR)) {
357                 t->user_cntd0 = t->user_cntd1 = NULL;
358                 t->pcr_reg = 0;
359                 write_pcr(0);
360         }
361 }
362
363 void flush_thread(void)
364 {
365         struct thread_info *t = current_thread_info();
366         struct mm_struct *mm;
367
368         mm = t->task->mm;
369         if (mm)
370                 tsb_context_switch(mm);
371
372         set_thread_wsaved(0);
373
374         /* Turn off performance counters if on. */
375         if (test_and_clear_thread_flag(TIF_PERFCTR)) {
376                 t->user_cntd0 = t->user_cntd1 = NULL;
377                 t->pcr_reg = 0;
378                 write_pcr(0);
379         }
380
381         /* Clear FPU register state. */
382         t->fpsaved[0] = 0;
383         
384         if (get_thread_current_ds() != ASI_AIUS)
385                 set_fs(USER_DS);
386 }
387
388 /* It's a bit more tricky when 64-bit tasks are involved... */
389 static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
390 {
391         unsigned long fp, distance, rval;
392
393         if (!(test_thread_flag(TIF_32BIT))) {
394                 csp += STACK_BIAS;
395                 psp += STACK_BIAS;
396                 __get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
397                 fp += STACK_BIAS;
398         } else
399                 __get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
400
401         /* Now 8-byte align the stack as this is mandatory in the
402          * Sparc ABI due to how register windows work.  This hides
403          * the restriction from thread libraries etc.  -DaveM
404          */
405         csp &= ~7UL;
406
407         distance = fp - psp;
408         rval = (csp - distance);
409         if (copy_in_user((void __user *) rval, (void __user *) psp, distance))
410                 rval = 0;
411         else if (test_thread_flag(TIF_32BIT)) {
412                 if (put_user(((u32)csp),
413                              &(((struct reg_window32 __user *)rval)->ins[6])))
414                         rval = 0;
415         } else {
416                 if (put_user(((u64)csp - STACK_BIAS),
417                              &(((struct reg_window __user *)rval)->ins[6])))
418                         rval = 0;
419                 else
420                         rval = rval - STACK_BIAS;
421         }
422
423         return rval;
424 }
425
426 /* Standard stuff. */
427 static inline void shift_window_buffer(int first_win, int last_win,
428                                        struct thread_info *t)
429 {
430         int i;
431
432         for (i = first_win; i < last_win; i++) {
433                 t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
434                 memcpy(&t->reg_window[i], &t->reg_window[i+1],
435                        sizeof(struct reg_window));
436         }
437 }
438
439 void synchronize_user_stack(void)
440 {
441         struct thread_info *t = current_thread_info();
442         unsigned long window;
443
444         flush_user_windows();
445         if ((window = get_thread_wsaved()) != 0) {
446                 int winsize = sizeof(struct reg_window);
447                 int bias = 0;
448
449                 if (test_thread_flag(TIF_32BIT))
450                         winsize = sizeof(struct reg_window32);
451                 else
452                         bias = STACK_BIAS;
453
454                 window -= 1;
455                 do {
456                         unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
457                         struct reg_window *rwin = &t->reg_window[window];
458
459                         if (!copy_to_user((char __user *)sp, rwin, winsize)) {
460                                 shift_window_buffer(window, get_thread_wsaved() - 1, t);
461                                 set_thread_wsaved(get_thread_wsaved() - 1);
462                         }
463                 } while (window--);
464         }
465 }
466
467 static void stack_unaligned(unsigned long sp)
468 {
469         siginfo_t info;
470
471         info.si_signo = SIGBUS;
472         info.si_errno = 0;
473         info.si_code = BUS_ADRALN;
474         info.si_addr = (void __user *) sp;
475         info.si_trapno = 0;
476         force_sig_info(SIGBUS, &info, current);
477 }
478
479 void fault_in_user_windows(void)
480 {
481         struct thread_info *t = current_thread_info();
482         unsigned long window;
483         int winsize = sizeof(struct reg_window);
484         int bias = 0;
485
486         if (test_thread_flag(TIF_32BIT))
487                 winsize = sizeof(struct reg_window32);
488         else
489                 bias = STACK_BIAS;
490
491         flush_user_windows();
492         window = get_thread_wsaved();
493
494         if (likely(window != 0)) {
495                 window -= 1;
496                 do {
497                         unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
498                         struct reg_window *rwin = &t->reg_window[window];
499
500                         if (unlikely(sp & 0x7UL))
501                                 stack_unaligned(sp);
502
503                         if (unlikely(copy_to_user((char __user *)sp,
504                                                   rwin, winsize)))
505                                 goto barf;
506                 } while (window--);
507         }
508         set_thread_wsaved(0);
509         return;
510
511 barf:
512         set_thread_wsaved(window + 1);
513         do_exit(SIGILL);
514 }
515
516 asmlinkage long sparc_do_fork(unsigned long clone_flags,
517                               unsigned long stack_start,
518                               struct pt_regs *regs,
519                               unsigned long stack_size)
520 {
521         int __user *parent_tid_ptr, *child_tid_ptr;
522         unsigned long orig_i1 = regs->u_regs[UREG_I1];
523         long ret;
524
525 #ifdef CONFIG_COMPAT
526         if (test_thread_flag(TIF_32BIT)) {
527                 parent_tid_ptr = compat_ptr(regs->u_regs[UREG_I2]);
528                 child_tid_ptr = compat_ptr(regs->u_regs[UREG_I4]);
529         } else
530 #endif
531         {
532                 parent_tid_ptr = (int __user *) regs->u_regs[UREG_I2];
533                 child_tid_ptr = (int __user *) regs->u_regs[UREG_I4];
534         }
535
536         ret = do_fork(clone_flags, stack_start,
537                       regs, stack_size,
538                       parent_tid_ptr, child_tid_ptr);
539
540         /* If we get an error and potentially restart the system
541          * call, we're screwed because copy_thread() clobbered
542          * the parent's %o1.  So detect that case and restore it
543          * here.
544          */
545         if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
546                 regs->u_regs[UREG_I1] = orig_i1;
547
548         return ret;
549 }
550
551 /* Copy a Sparc thread.  The fork() return value conventions
552  * under SunOS are nothing short of bletcherous:
553  * Parent -->  %o0 == childs  pid, %o1 == 0
554  * Child  -->  %o0 == parents pid, %o1 == 1
555  */
556 int copy_thread(unsigned long clone_flags, unsigned long sp,
557                 unsigned long unused,
558                 struct task_struct *p, struct pt_regs *regs)
559 {
560         struct thread_info *t = task_thread_info(p);
561         struct sparc_stackf *parent_sf;
562         unsigned long child_stack_sz;
563         char *child_trap_frame;
564         int kernel_thread;
565
566         kernel_thread = (regs->tstate & TSTATE_PRIV) ? 1 : 0;
567         parent_sf = ((struct sparc_stackf *) regs) - 1;
568
569         /* Calculate offset to stack_frame & pt_regs */
570         child_stack_sz = ((STACKFRAME_SZ + TRACEREG_SZ) +
571                           (kernel_thread ? STACKFRAME_SZ : 0));
572         child_trap_frame = (task_stack_page(p) +
573                             (THREAD_SIZE - child_stack_sz));
574         memcpy(child_trap_frame, parent_sf, child_stack_sz);
575
576         t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) |
577                                  (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
578                 (((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
579         t->new_child = 1;
580         t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
581         t->kregs = (struct pt_regs *) (child_trap_frame +
582                                        sizeof(struct sparc_stackf));
583         t->fpsaved[0] = 0;
584
585         if (kernel_thread) {
586                 struct sparc_stackf *child_sf = (struct sparc_stackf *)
587                         (child_trap_frame + (STACKFRAME_SZ + TRACEREG_SZ));
588
589                 /* Zero terminate the stack backtrace.  */
590                 child_sf->fp = NULL;
591                 t->kregs->u_regs[UREG_FP] =
592                   ((unsigned long) child_sf) - STACK_BIAS;
593
594                 /* Special case, if we are spawning a kernel thread from
595                  * a userspace task (usermode helper, NFS or similar), we
596                  * must disable performance counters in the child because
597                  * the address space and protection realm are changing.
598                  */
599                 if (t->flags & _TIF_PERFCTR) {
600                         t->user_cntd0 = t->user_cntd1 = NULL;
601                         t->pcr_reg = 0;
602                         t->flags &= ~_TIF_PERFCTR;
603                 }
604                 t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
605                 t->kregs->u_regs[UREG_G6] = (unsigned long) t;
606                 t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
607         } else {
608                 if (t->flags & _TIF_32BIT) {
609                         sp &= 0x00000000ffffffffUL;
610                         regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
611                 }
612                 t->kregs->u_regs[UREG_FP] = sp;
613                 t->flags |= ((long)ASI_AIUS << TI_FLAG_CURRENT_DS_SHIFT);
614                 if (sp != regs->u_regs[UREG_FP]) {
615                         unsigned long csp;
616
617                         csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
618                         if (!csp)
619                                 return -EFAULT;
620                         t->kregs->u_regs[UREG_FP] = csp;
621                 }
622                 if (t->utraps)
623                         t->utraps[0]++;
624         }
625
626         /* Set the return value for the child. */
627         t->kregs->u_regs[UREG_I0] = current->pid;
628         t->kregs->u_regs[UREG_I1] = 1;
629
630         /* Set the second return value for the parent. */
631         regs->u_regs[UREG_I1] = 0;
632
633         if (clone_flags & CLONE_SETTLS)
634                 t->kregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
635
636         return 0;
637 }
638
639 /*
640  * This is the mechanism for creating a new kernel thread.
641  *
642  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
643  * who haven't done an "execve()") should use this: it will work within
644  * a system call from a "real" process, but the process memory space will
645  * not be freed until both the parent and the child have exited.
646  */
647 pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
648 {
649         long retval;
650
651         /* If the parent runs before fn(arg) is called by the child,
652          * the input registers of this function can be clobbered.
653          * So we stash 'fn' and 'arg' into global registers which
654          * will not be modified by the parent.
655          */
656         __asm__ __volatile__("mov %4, %%g2\n\t"    /* Save FN into global */
657                              "mov %5, %%g3\n\t"    /* Save ARG into global */
658                              "mov %1, %%g1\n\t"    /* Clone syscall nr. */
659                              "mov %2, %%o0\n\t"    /* Clone flags. */
660                              "mov 0, %%o1\n\t"     /* usp arg == 0 */
661                              "t 0x6d\n\t"          /* Linux/Sparc clone(). */
662                              "brz,a,pn %%o1, 1f\n\t" /* Parent, just return. */
663                              " mov %%o0, %0\n\t"
664                              "jmpl %%g2, %%o7\n\t"   /* Call the function. */
665                              " mov %%g3, %%o0\n\t"   /* Set arg in delay. */
666                              "mov %3, %%g1\n\t"
667                              "t 0x6d\n\t"          /* Linux/Sparc exit(). */
668                              /* Notreached by child. */
669                              "1:" :
670                              "=r" (retval) :
671                              "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
672                              "i" (__NR_exit),  "r" (fn), "r" (arg) :
673                              "g1", "g2", "g3", "o0", "o1", "memory", "cc");
674         return retval;
675 }
676 EXPORT_SYMBOL(kernel_thread);
677
678 typedef struct {
679         union {
680                 unsigned int    pr_regs[32];
681                 unsigned long   pr_dregs[16];
682         } pr_fr;
683         unsigned int __unused;
684         unsigned int    pr_fsr;
685         unsigned char   pr_qcnt;
686         unsigned char   pr_q_entrysize;
687         unsigned char   pr_en;
688         unsigned int    pr_q[64];
689 } elf_fpregset_t32;
690
691 /*
692  * fill in the fpu structure for a core dump.
693  */
694 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
695 {
696         unsigned long *kfpregs = current_thread_info()->fpregs;
697         unsigned long fprs = current_thread_info()->fpsaved[0];
698
699         if (test_thread_flag(TIF_32BIT)) {
700                 elf_fpregset_t32 *fpregs32 = (elf_fpregset_t32 *)fpregs;
701
702                 if (fprs & FPRS_DL)
703                         memcpy(&fpregs32->pr_fr.pr_regs[0], kfpregs,
704                                sizeof(unsigned int) * 32);
705                 else
706                         memset(&fpregs32->pr_fr.pr_regs[0], 0,
707                                sizeof(unsigned int) * 32);
708                 fpregs32->pr_qcnt = 0;
709                 fpregs32->pr_q_entrysize = 8;
710                 memset(&fpregs32->pr_q[0], 0,
711                        (sizeof(unsigned int) * 64));
712                 if (fprs & FPRS_FEF) {
713                         fpregs32->pr_fsr = (unsigned int) current_thread_info()->xfsr[0];
714                         fpregs32->pr_en = 1;
715                 } else {
716                         fpregs32->pr_fsr = 0;
717                         fpregs32->pr_en = 0;
718                 }
719         } else {
720                 if(fprs & FPRS_DL)
721                         memcpy(&fpregs->pr_regs[0], kfpregs,
722                                sizeof(unsigned int) * 32);
723                 else
724                         memset(&fpregs->pr_regs[0], 0,
725                                sizeof(unsigned int) * 32);
726                 if(fprs & FPRS_DU)
727                         memcpy(&fpregs->pr_regs[16], kfpregs+16,
728                                sizeof(unsigned int) * 32);
729                 else
730                         memset(&fpregs->pr_regs[16], 0,
731                                sizeof(unsigned int) * 32);
732                 if(fprs & FPRS_FEF) {
733                         fpregs->pr_fsr = current_thread_info()->xfsr[0];
734                         fpregs->pr_gsr = current_thread_info()->gsr[0];
735                 } else {
736                         fpregs->pr_fsr = fpregs->pr_gsr = 0;
737                 }
738                 fpregs->pr_fprs = fprs;
739         }
740         return 1;
741 }
742 EXPORT_SYMBOL(dump_fpu);
743
744 /*
745  * sparc_execve() executes a new program after the asm stub has set
746  * things up for us.  This should basically do what I want it to.
747  */
748 asmlinkage int sparc_execve(struct pt_regs *regs)
749 {
750         int error, base = 0;
751         char *filename;
752
753         /* User register window flush is done by entry.S */
754
755         /* Check for indirect call. */
756         if (regs->u_regs[UREG_G1] == 0)
757                 base = 1;
758
759         filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
760         error = PTR_ERR(filename);
761         if (IS_ERR(filename))
762                 goto out;
763         error = do_execve(filename,
764                           (char __user * __user *)
765                           regs->u_regs[base + UREG_I1],
766                           (char __user * __user *)
767                           regs->u_regs[base + UREG_I2], regs);
768         putname(filename);
769         if (!error) {
770                 fprs_write(0);
771                 current_thread_info()->xfsr[0] = 0;
772                 current_thread_info()->fpsaved[0] = 0;
773                 regs->tstate &= ~TSTATE_PEF;
774         }
775 out:
776         return error;
777 }
778
779 unsigned long get_wchan(struct task_struct *task)
780 {
781         unsigned long pc, fp, bias = 0;
782         struct thread_info *tp;
783         struct reg_window *rw;
784         unsigned long ret = 0;
785         int count = 0; 
786
787         if (!task || task == current ||
788             task->state == TASK_RUNNING)
789                 goto out;
790
791         tp = task_thread_info(task);
792         bias = STACK_BIAS;
793         fp = task_thread_info(task)->ksp + bias;
794
795         do {
796                 if (!kstack_valid(tp, fp))
797                         break;
798                 rw = (struct reg_window *) fp;
799                 pc = rw->ins[7];
800                 if (!in_sched_functions(pc)) {
801                         ret = pc;
802                         goto out;
803                 }
804                 fp = rw->ins[6] + bias;
805         } while (++count < 16);
806
807 out:
808         return ret;
809 }