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[PATCH] sched: disable preempt in idle tasks
[linux-2.6-block.git] / arch / sh64 / kernel / process.c
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1da177e4
LT		 1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * arch/sh64/kernel/process.c
7 *
8 * Copyright (C) 2000, 2001 Paolo Alberelli
9 * Copyright (C) 2003 Paul Mundt
10 * Copyright (C) 2003, 2004 Richard Curnow
11 *
12 * Started from SH3/4 version:
13 * Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
14 *
15 * In turn started from i386 version:
16 * Copyright (C) 1995 Linus Torvalds
17 *
18 */
19
20/*
21 * This file handles the architecture-dependent parts of process handling..
22 */
23
24/* Temporary flags/tests. All to be removed/undefined. BEGIN */
25#define IDLE_TRACE
26#define VM_SHOW_TABLES
27#define VM_TEST_FAULT
28#define VM_TEST_RTLBMISS
29#define VM_TEST_WTLBMISS
30
31#undef VM_SHOW_TABLES
32#undef IDLE_TRACE
33/* Temporary flags/tests. All to be removed/undefined. END */
34
35#define __KERNEL_SYSCALLS__
36#include <stdarg.h>
37
38#include <linux/config.h>
39#include <linux/kernel.h>
40#include <linux/rwsem.h>
41#include <linux/mm.h>
42#include <linux/smp.h>
43#include <linux/smp_lock.h>
44#include <linux/ptrace.h>
45#include <linux/slab.h>
46#include <linux/vmalloc.h>
47#include <linux/user.h>
48#include <linux/a.out.h>
49#include <linux/interrupt.h>
50#include <linux/unistd.h>
51#include <linux/delay.h>
52#include <linux/reboot.h>
53#include <linux/init.h>
54
55#include <asm/uaccess.h>
56#include <asm/pgtable.h>
57#include <asm/system.h>
58#include <asm/io.h>
59#include <asm/processor.h> /* includes also <asm/registers.h> */
60#include <asm/mmu_context.h>
61#include <asm/elf.h>
62#include <asm/page.h>
63
64#include <linux/irq.h>
65
66struct task_struct *last_task_used_math = NULL;
67
68#ifdef IDLE_TRACE
69#ifdef VM_SHOW_TABLES
70/* For testing */
71static void print_PTE(long base)
72{
73 int i, skip=0;
74 long long x, y, *p = (long long *) base;
75
76 for (i=0; i< 512; i++, p++){
77 if (*p == 0) {
78 if (!skip) {
79 skip++;
80 printk("(0s) ");
81 }
82 } else {
83 skip=0;
84 x = (*p) >> 32;
85 y = (*p) & 0xffffffff;
86 printk("%08Lx%08Lx ", x, y);
87 if (!((i+1)&0x3)) printk("\n");
88 }
89 }
90}
91
92/* For testing */
93static void print_DIR(long base)
94{
95 int i, skip=0;
96 long *p = (long *) base;
97
98 for (i=0; i< 512; i++, p++){
99 if (*p == 0) {
100 if (!skip) {
101 skip++;
102 printk("(0s) ");
103 }
104 } else {
105 skip=0;
106 printk("%08lx ", *p);
107 if (!((i+1)&0x7)) printk("\n");
108 }
109 }
110}
111
112/* For testing */
113static void print_vmalloc_first_tables(void)
114{
115
116#define PRESENT 0x800 /* Bit 11 */
117
118 /*
119 * Do it really dirty by looking at raw addresses,
120 * raw offsets, no types. If we used pgtable/pgalloc
121 * macros/definitions we could hide potential bugs.
122 *
123 * Note that pointers are 32-bit for CDC.
124 */
125 long pgdt, pmdt, ptet;
126
127 pgdt = (long) &swapper_pg_dir;
128 printk("-->PGD (0x%08lx):\n", pgdt);
129 print_DIR(pgdt);
130 printk("\n");
131
132 /* VMALLOC pool is mapped at 0xc0000000, second (pointer) entry in PGD */
133 pgdt += 4;
134 pmdt = (long) (* (long *) pgdt);
135 if (!(pmdt & PRESENT)) {
136 printk("No PMD\n");
137 return;
138 } else pmdt &= 0xfffff000;
139
140 printk("-->PMD (0x%08lx):\n", pmdt);
141 print_DIR(pmdt);
142 printk("\n");
143
144 /* Get the pmdt displacement for 0xc0000000 */
145 pmdt += 2048;
146
147 /* just look at first two address ranges ... */
148 /* ... 0xc0000000 ... */
149 ptet = (long) (* (long *) pmdt);
150 if (!(ptet & PRESENT)) {
151 printk("No PTE0\n");
152 return;
153 } else ptet &= 0xfffff000;
154
155 printk("-->PTE0 (0x%08lx):\n", ptet);
156 print_PTE(ptet);
157 printk("\n");
158
159 /* ... 0xc0001000 ... */
160 ptet += 4;
161 if (!(ptet & PRESENT)) {
162 printk("No PTE1\n");
163 return;
164 } else ptet &= 0xfffff000;
165 printk("-->PTE1 (0x%08lx):\n", ptet);
166 print_PTE(ptet);
167 printk("\n");
168}
169#else
170#define print_vmalloc_first_tables()
171#endif /* VM_SHOW_TABLES */
172
173static void test_VM(void)
174{
175 void *a, *b, *c;
176
177#ifdef VM_SHOW_TABLES
178 printk("Initial PGD/PMD/PTE\n");
179#endif
180 print_vmalloc_first_tables();
181
182 printk("Allocating 2 bytes\n");
183 a = vmalloc(2);
184 print_vmalloc_first_tables();
185
186 printk("Allocating 4100 bytes\n");
187 b = vmalloc(4100);
188 print_vmalloc_first_tables();
189
190 printk("Allocating 20234 bytes\n");
191 c = vmalloc(20234);
192 print_vmalloc_first_tables();
193
194#ifdef VM_TEST_FAULT
195 /* Here you may want to fault ! */
196
197#ifdef VM_TEST_RTLBMISS
198 printk("Ready to fault upon read.\n");
199 if (* (char *) a) {
200 printk("RTLBMISSed on area a !\n");
201 }
202 printk("RTLBMISSed on area a !\n");
203#endif
204
205#ifdef VM_TEST_WTLBMISS
206 printk("Ready to fault upon write.\n");
207 *((char *) b) = 'L';
208 printk("WTLBMISSed on area b !\n");
209#endif
210
211#endif /* VM_TEST_FAULT */
212
213 printk("Deallocating the 4100 byte chunk\n");
214 vfree(b);
215 print_vmalloc_first_tables();
216
217 printk("Deallocating the 2 byte chunk\n");
218 vfree(a);
219 print_vmalloc_first_tables();
220
221 printk("Deallocating the last chunk\n");
222 vfree(c);
223 print_vmalloc_first_tables();
224}
225
226extern unsigned long volatile jiffies;
227int once = 0;
228unsigned long old_jiffies;
229int pid = -1, pgid = -1;
230
231void idle_trace(void)
232{
233
234 _syscall0(int, getpid)
235 _syscall1(int, getpgid, int, pid)
236
237 if (!once) {
238 /* VM allocation/deallocation simple test */
239 test_VM();
240 pid = getpid();
241
242 printk("Got all through to Idle !!\n");
243 printk("I'm now going to loop forever ...\n");
244 printk("Any ! below is a timer tick.\n");
245 printk("Any . below is a getpgid system call from pid = %d.\n", pid);
246
247
248 old_jiffies = jiffies;
249 once++;
250 }
251
252 if (old_jiffies != jiffies) {
253 old_jiffies = jiffies - old_jiffies;
254 switch (old_jiffies) {
255 case 1:
256 printk("!");
257 break;
258 case 2:
259 printk("!!");
260 break;
261 case 3:
262 printk("!!!");
263 break;
264 case 4:
265 printk("!!!!");
266 break;
267 default:
268 printk("(%d!)", (int) old_jiffies);
269 }
270 old_jiffies = jiffies;
271 }
272 pgid = getpgid(pid);
273 printk(".");
274}
275#else
276#define idle_trace() do { } while (0)
277#endif /* IDLE_TRACE */
278
279static int hlt_counter = 1;
280
281#define HARD_IDLE_TIMEOUT (HZ / 3)
282
283void disable_hlt(void)
284{
285 hlt_counter++;
286}
287
288void enable_hlt(void)
289{
290 hlt_counter--;
291}
292
293static int __init nohlt_setup(char *__unused)
294{
295 hlt_counter = 1;
296 return 1;
297}
298
299static int __init hlt_setup(char *__unused)
300{
301 hlt_counter = 0;
302 return 1;
303}
304
305__setup("nohlt", nohlt_setup);
306__setup("hlt", hlt_setup);
307
308static inline void hlt(void)
309{
310 if (hlt_counter)
311 return;
312
313 __asm__ __volatile__ ("sleep" : : : "memory");
314}
315
316/*
317 * The idle loop on a uniprocessor SH..
318 */
319void default_idle(void)
320{
321 /* endless idle loop with no priority at all */
322 while (1) {
323 if (hlt_counter) {
324 while (1)
325 if (need_resched())
326 break;
327 } else {
328 local_irq_disable();
329 while (!need_resched()) {
330 local_irq_enable();
331 idle_trace();
332 hlt();
333 local_irq_disable();
334 }
335 local_irq_enable();
336 }
5bfb5d69 337 preempt_enable_no_resched();
1da177e4 338 schedule();
5bfb5d69 339 preempt_disable();
1da177e4
LT		 340 }
341}
342
343void cpu_idle(void)
344{
345 default_idle();
346}
347
348void machine_restart(char * __unused)
349{
350 extern void phys_stext(void);
351
352 phys_stext();
353}
354
355void machine_halt(void)
356{
357 for (;;);
358}
359
360void machine_power_off(void)
361{
362 extern void enter_deep_standby(void);
363
364 enter_deep_standby();
365}
366
367void show_regs(struct pt_regs * regs)
368{
369 unsigned long long ah, al, bh, bl, ch, cl;
370
371 printk("\n");
372
373 ah = (regs->pc) >> 32;
374 al = (regs->pc) & 0xffffffff;
375 bh = (regs->regs[18]) >> 32;
376 bl = (regs->regs[18]) & 0xffffffff;
377 ch = (regs->regs[15]) >> 32;
378 cl = (regs->regs[15]) & 0xffffffff;
379 printk("PC : %08Lx%08Lx LINK: %08Lx%08Lx SP : %08Lx%08Lx\n",
380 ah, al, bh, bl, ch, cl);
381
382 ah = (regs->sr) >> 32;
383 al = (regs->sr) & 0xffffffff;
384 asm volatile ("getcon " __TEA ", %0" : "=r" (bh));
385 asm volatile ("getcon " __TEA ", %0" : "=r" (bl));
386 bh = (bh) >> 32;
387 bl = (bl) & 0xffffffff;
388 asm volatile ("getcon " __KCR0 ", %0" : "=r" (ch));
389 asm volatile ("getcon " __KCR0 ", %0" : "=r" (cl));
390 ch = (ch) >> 32;
391 cl = (cl) & 0xffffffff;
392 printk("SR : %08Lx%08Lx TEA : %08Lx%08Lx KCR0: %08Lx%08Lx\n",
393 ah, al, bh, bl, ch, cl);
394
395 ah = (regs->regs[0]) >> 32;
396 al = (regs->regs[0]) & 0xffffffff;
397 bh = (regs->regs[1]) >> 32;
398 bl = (regs->regs[1]) & 0xffffffff;
399 ch = (regs->regs[2]) >> 32;
400 cl = (regs->regs[2]) & 0xffffffff;
401 printk("R0 : %08Lx%08Lx R1 : %08Lx%08Lx R2 : %08Lx%08Lx\n",
402 ah, al, bh, bl, ch, cl);
403
404 ah = (regs->regs[3]) >> 32;
405 al = (regs->regs[3]) & 0xffffffff;
406 bh = (regs->regs[4]) >> 32;
407 bl = (regs->regs[4]) & 0xffffffff;
408 ch = (regs->regs[5]) >> 32;
409 cl = (regs->regs[5]) & 0xffffffff;
410 printk("R3 : %08Lx%08Lx R4 : %08Lx%08Lx R5 : %08Lx%08Lx\n",
411 ah, al, bh, bl, ch, cl);
412
413 ah = (regs->regs[6]) >> 32;
414 al = (regs->regs[6]) & 0xffffffff;
415 bh = (regs->regs[7]) >> 32;
416 bl = (regs->regs[7]) & 0xffffffff;
417 ch = (regs->regs[8]) >> 32;
418 cl = (regs->regs[8]) & 0xffffffff;
419 printk("R6 : %08Lx%08Lx R7 : %08Lx%08Lx R8 : %08Lx%08Lx\n",
420 ah, al, bh, bl, ch, cl);
421
422 ah = (regs->regs[9]) >> 32;
423 al = (regs->regs[9]) & 0xffffffff;
424 bh = (regs->regs[10]) >> 32;
425 bl = (regs->regs[10]) & 0xffffffff;
426 ch = (regs->regs[11]) >> 32;
427 cl = (regs->regs[11]) & 0xffffffff;
428 printk("R9 : %08Lx%08Lx R10 : %08Lx%08Lx R11 : %08Lx%08Lx\n",
429 ah, al, bh, bl, ch, cl);
430
431 ah = (regs->regs[12]) >> 32;
432 al = (regs->regs[12]) & 0xffffffff;
433 bh = (regs->regs[13]) >> 32;
434 bl = (regs->regs[13]) & 0xffffffff;
435 ch = (regs->regs[14]) >> 32;
436 cl = (regs->regs[14]) & 0xffffffff;
437 printk("R12 : %08Lx%08Lx R13 : %08Lx%08Lx R14 : %08Lx%08Lx\n",
438 ah, al, bh, bl, ch, cl);
439
440 ah = (regs->regs[16]) >> 32;
441 al = (regs->regs[16]) & 0xffffffff;
442 bh = (regs->regs[17]) >> 32;
443 bl = (regs->regs[17]) & 0xffffffff;
444 ch = (regs->regs[19]) >> 32;
445 cl = (regs->regs[19]) & 0xffffffff;
446 printk("R16 : %08Lx%08Lx R17 : %08Lx%08Lx R19 : %08Lx%08Lx\n",
447 ah, al, bh, bl, ch, cl);
448
449 ah = (regs->regs[20]) >> 32;
450 al = (regs->regs[20]) & 0xffffffff;
451 bh = (regs->regs[21]) >> 32;
452 bl = (regs->regs[21]) & 0xffffffff;
453 ch = (regs->regs[22]) >> 32;
454 cl = (regs->regs[22]) & 0xffffffff;
455 printk("R20 : %08Lx%08Lx R21 : %08Lx%08Lx R22 : %08Lx%08Lx\n",
456 ah, al, bh, bl, ch, cl);
457
458 ah = (regs->regs[23]) >> 32;
459 al = (regs->regs[23]) & 0xffffffff;
460 bh = (regs->regs[24]) >> 32;
461 bl = (regs->regs[24]) & 0xffffffff;
462 ch = (regs->regs[25]) >> 32;
463 cl = (regs->regs[25]) & 0xffffffff;
464 printk("R23 : %08Lx%08Lx R24 : %08Lx%08Lx R25 : %08Lx%08Lx\n",
465 ah, al, bh, bl, ch, cl);
466
467 ah = (regs->regs[26]) >> 32;
468 al = (regs->regs[26]) & 0xffffffff;
469 bh = (regs->regs[27]) >> 32;
470 bl = (regs->regs[27]) & 0xffffffff;
471 ch = (regs->regs[28]) >> 32;
472 cl = (regs->regs[28]) & 0xffffffff;
473 printk("R26 : %08Lx%08Lx R27 : %08Lx%08Lx R28 : %08Lx%08Lx\n",
474 ah, al, bh, bl, ch, cl);
475
476 ah = (regs->regs[29]) >> 32;
477 al = (regs->regs[29]) & 0xffffffff;
478 bh = (regs->regs[30]) >> 32;
479 bl = (regs->regs[30]) & 0xffffffff;
480 ch = (regs->regs[31]) >> 32;
481 cl = (regs->regs[31]) & 0xffffffff;
482 printk("R29 : %08Lx%08Lx R30 : %08Lx%08Lx R31 : %08Lx%08Lx\n",
483 ah, al, bh, bl, ch, cl);
484
485 ah = (regs->regs[32]) >> 32;
486 al = (regs->regs[32]) & 0xffffffff;
487 bh = (regs->regs[33]) >> 32;
488 bl = (regs->regs[33]) & 0xffffffff;
489 ch = (regs->regs[34]) >> 32;
490 cl = (regs->regs[34]) & 0xffffffff;
491 printk("R32 : %08Lx%08Lx R33 : %08Lx%08Lx R34 : %08Lx%08Lx\n",
492 ah, al, bh, bl, ch, cl);
493
494 ah = (regs->regs[35]) >> 32;
495 al = (regs->regs[35]) & 0xffffffff;
496 bh = (regs->regs[36]) >> 32;
497 bl = (regs->regs[36]) & 0xffffffff;
498 ch = (regs->regs[37]) >> 32;
499 cl = (regs->regs[37]) & 0xffffffff;
500 printk("R35 : %08Lx%08Lx R36 : %08Lx%08Lx R37 : %08Lx%08Lx\n",
501 ah, al, bh, bl, ch, cl);
502
503 ah = (regs->regs[38]) >> 32;
504 al = (regs->regs[38]) & 0xffffffff;
505 bh = (regs->regs[39]) >> 32;
506 bl = (regs->regs[39]) & 0xffffffff;
507 ch = (regs->regs[40]) >> 32;
508 cl = (regs->regs[40]) & 0xffffffff;
509 printk("R38 : %08Lx%08Lx R39 : %08Lx%08Lx R40 : %08Lx%08Lx\n",
510 ah, al, bh, bl, ch, cl);
511
512 ah = (regs->regs[41]) >> 32;
513 al = (regs->regs[41]) & 0xffffffff;
514 bh = (regs->regs[42]) >> 32;
515 bl = (regs->regs[42]) & 0xffffffff;
516 ch = (regs->regs[43]) >> 32;
517 cl = (regs->regs[43]) & 0xffffffff;
518 printk("R41 : %08Lx%08Lx R42 : %08Lx%08Lx R43 : %08Lx%08Lx\n",
519 ah, al, bh, bl, ch, cl);
520
521 ah = (regs->regs[44]) >> 32;
522 al = (regs->regs[44]) & 0xffffffff;
523 bh = (regs->regs[45]) >> 32;
524 bl = (regs->regs[45]) & 0xffffffff;
525 ch = (regs->regs[46]) >> 32;
526 cl = (regs->regs[46]) & 0xffffffff;
527 printk("R44 : %08Lx%08Lx R45 : %08Lx%08Lx R46 : %08Lx%08Lx\n",
528 ah, al, bh, bl, ch, cl);
529
530 ah = (regs->regs[47]) >> 32;
531 al = (regs->regs[47]) & 0xffffffff;
532 bh = (regs->regs[48]) >> 32;
533 bl = (regs->regs[48]) & 0xffffffff;
534 ch = (regs->regs[49]) >> 32;
535 cl = (regs->regs[49]) & 0xffffffff;
536 printk("R47 : %08Lx%08Lx R48 : %08Lx%08Lx R49 : %08Lx%08Lx\n",
537 ah, al, bh, bl, ch, cl);
538
539 ah = (regs->regs[50]) >> 32;
540 al = (regs->regs[50]) & 0xffffffff;
541 bh = (regs->regs[51]) >> 32;
542 bl = (regs->regs[51]) & 0xffffffff;
543 ch = (regs->regs[52]) >> 32;
544 cl = (regs->regs[52]) & 0xffffffff;
545 printk("R50 : %08Lx%08Lx R51 : %08Lx%08Lx R52 : %08Lx%08Lx\n",
546 ah, al, bh, bl, ch, cl);
547
548 ah = (regs->regs[53]) >> 32;
549 al = (regs->regs[53]) & 0xffffffff;
550 bh = (regs->regs[54]) >> 32;
551 bl = (regs->regs[54]) & 0xffffffff;
552 ch = (regs->regs[55]) >> 32;
553 cl = (regs->regs[55]) & 0xffffffff;
554 printk("R53 : %08Lx%08Lx R54 : %08Lx%08Lx R55 : %08Lx%08Lx\n",
555 ah, al, bh, bl, ch, cl);
556
557 ah = (regs->regs[56]) >> 32;
558 al = (regs->regs[56]) & 0xffffffff;
559 bh = (regs->regs[57]) >> 32;
560 bl = (regs->regs[57]) & 0xffffffff;
561 ch = (regs->regs[58]) >> 32;
562 cl = (regs->regs[58]) & 0xffffffff;
563 printk("R56 : %08Lx%08Lx R57 : %08Lx%08Lx R58 : %08Lx%08Lx\n",
564 ah, al, bh, bl, ch, cl);
565
566 ah = (regs->regs[59]) >> 32;
567 al = (regs->regs[59]) & 0xffffffff;
568 bh = (regs->regs[60]) >> 32;
569 bl = (regs->regs[60]) & 0xffffffff;
570 ch = (regs->regs[61]) >> 32;
571 cl = (regs->regs[61]) & 0xffffffff;
572 printk("R59 : %08Lx%08Lx R60 : %08Lx%08Lx R61 : %08Lx%08Lx\n",
573 ah, al, bh, bl, ch, cl);
574
575 ah = (regs->regs[62]) >> 32;
576 al = (regs->regs[62]) & 0xffffffff;
577 bh = (regs->tregs[0]) >> 32;
578 bl = (regs->tregs[0]) & 0xffffffff;
579 ch = (regs->tregs[1]) >> 32;
580 cl = (regs->tregs[1]) & 0xffffffff;
581 printk("R62 : %08Lx%08Lx T0 : %08Lx%08Lx T1 : %08Lx%08Lx\n",
582 ah, al, bh, bl, ch, cl);
583
584 ah = (regs->tregs[2]) >> 32;
585 al = (regs->tregs[2]) & 0xffffffff;
586 bh = (regs->tregs[3]) >> 32;
587 bl = (regs->tregs[3]) & 0xffffffff;
588 ch = (regs->tregs[4]) >> 32;
589 cl = (regs->tregs[4]) & 0xffffffff;
590 printk("T2 : %08Lx%08Lx T3 : %08Lx%08Lx T4 : %08Lx%08Lx\n",
591 ah, al, bh, bl, ch, cl);
592
593 ah = (regs->tregs[5]) >> 32;
594 al = (regs->tregs[5]) & 0xffffffff;
595 bh = (regs->tregs[6]) >> 32;
596 bl = (regs->tregs[6]) & 0xffffffff;
597 ch = (regs->tregs[7]) >> 32;
598 cl = (regs->tregs[7]) & 0xffffffff;
599 printk("T5 : %08Lx%08Lx T6 : %08Lx%08Lx T7 : %08Lx%08Lx\n",
600 ah, al, bh, bl, ch, cl);
601
602 /*
603 * If we're in kernel mode, dump the stack too..
604 */
605 if (!user_mode(regs)) {
606 void show_stack(struct task_struct *tsk, unsigned long *sp);
607 unsigned long sp = regs->regs[15] & 0xffffffff;
608 struct task_struct *tsk = get_current();
609
610 tsk->thread.kregs = regs;
611
612 show_stack(tsk, (unsigned long *)sp);
613 }
614}
615
616struct task_struct * alloc_task_struct(void)
617{
618 /* Get task descriptor pages */
619 return (struct task_struct *)
620 __get_free_pages(GFP_KERNEL, get_order(THREAD_SIZE));
621}
622
623void free_task_struct(struct task_struct *p)
624{
625 free_pages((unsigned long) p, get_order(THREAD_SIZE));
626}
627
628/*
629 * Create a kernel thread
630 */
631
632/*
633 * This is the mechanism for creating a new kernel thread.
634 *
635 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
636 * who haven't done an "execve()") should use this: it will work within
637 * a system call from a "real" process, but the process memory space will
638 * not be free'd until both the parent and the child have exited.
639 */
640int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
641{
642 /* A bit less processor dependent than older sh ... */
643 unsigned int reply;
644
645static __inline__ _syscall2(int,clone,unsigned long,flags,unsigned long,newsp)
646static __inline__ _syscall1(int,exit,int,ret)
647
648 reply = clone(flags | CLONE_VM, 0);
649 if (!reply) {
650 /* Child */
651 reply = exit(fn(arg));
652 }
653
654 return reply;
655}
656
657/*
658 * Free current thread data structures etc..
659 */
660void exit_thread(void)
661{
662 /* See arch/sparc/kernel/process.c for the precedent for doing this -- RPC.
663
664 The SH-5 FPU save/restore approach relies on last_task_used_math
665 pointing to a live task_struct. When another task tries to use the
666 FPU for the 1st time, the FPUDIS trap handling (see
667 arch/sh64/kernel/fpu.c) will save the existing FPU state to the
668 FP regs field within last_task_used_math before re-loading the new
669 task's FPU state (or initialising it if the FPU has been used
670 before). So if last_task_used_math is stale, and its page has already been
671 re-allocated for another use, the consequences are rather grim. Unless we
672 null it here, there is no other path through which it would get safely
673 nulled. */
674
675#ifdef CONFIG_SH_FPU
676 if (last_task_used_math == current) {
677 last_task_used_math = NULL;
678 }
679#endif
680}
681
682void flush_thread(void)
683{
684
685 /* Called by fs/exec.c (flush_old_exec) to remove traces of a
686 * previously running executable. */
687#ifdef CONFIG_SH_FPU
688 if (last_task_used_math == current) {
689 last_task_used_math = NULL;
690 }
691 /* Force FPU state to be reinitialised after exec */
692 clear_used_math();
693#endif
694
695 /* if we are a kernel thread, about to change to user thread,
696 * update kreg
697 */
698 if(current->thread.kregs==&fake_swapper_regs) {
699 current->thread.kregs =
700 ((struct pt_regs *)(THREAD_SIZE + (unsigned long) current) - 1);
701 current->thread.uregs = current->thread.kregs;
702 }
703}
704
705void release_thread(struct task_struct *dead_task)
706{
707 /* do nothing */
708}
709
710/* Fill in the fpu structure for a core dump.. */
711int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
712{
713#ifdef CONFIG_SH_FPU
714 int fpvalid;
715 struct task_struct *tsk = current;
716
717 fpvalid = !!tsk_used_math(tsk);
718 if (fpvalid) {
719 if (current == last_task_used_math) {
720 grab_fpu();
721 fpsave(&tsk->thread.fpu.hard);
722 release_fpu();
723 last_task_used_math = 0;
724 regs->sr |= SR_FD;
725 }
726
727 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
728 }
729
730 return fpvalid;
731#else
732 return 0; /* Task didn't use the fpu at all. */
733#endif
734}
735
736asmlinkage void ret_from_fork(void);
737
738int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
739 unsigned long unused,
740 struct task_struct *p, struct pt_regs *regs)
741{
742 struct pt_regs *childregs;
743 unsigned long long se; /* Sign extension */
744
745#ifdef CONFIG_SH_FPU
746 if(last_task_used_math == current) {
747 grab_fpu();
748 fpsave(&current->thread.fpu.hard);
749 release_fpu();
750 last_task_used_math = NULL;
751 regs->sr |= SR_FD;
752 }
753#endif
754 /* Copy from sh version */
755 childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long) p->thread_info )) - 1;
756
757 *childregs = *regs;
758
759 if (user_mode(regs)) {
760 childregs->regs[15] = usp;
761 p->thread.uregs = childregs;
762 } else {
763 childregs->regs[15] = (unsigned long)p->thread_info + THREAD_SIZE;
764 }
765
766 childregs->regs[9] = 0; /* Set return value for child */
767 childregs->sr |= SR_FD; /* Invalidate FPU flag */
768
769 p->thread.sp = (unsigned long) childregs;
770 p->thread.pc = (unsigned long) ret_from_fork;
771
772 /*
773 * Sign extend the edited stack.
774 * Note that thread.pc and thread.pc will stay
775 * 32-bit wide and context switch must take care
776 * of NEFF sign extension.
777 */
778
779 se = childregs->regs[15];
780 se = (se & NEFF_SIGN) ? (se | NEFF_MASK) : se;
781 childregs->regs[15] = se;
782
783 return 0;
784}
785
786/*
787 * fill in the user structure for a core dump..
788 */
789void dump_thread(struct pt_regs * regs, struct user * dump)
790{
791 dump->magic = CMAGIC;
792 dump->start_code = current->mm->start_code;
793 dump->start_data = current->mm->start_data;
794 dump->start_stack = regs->regs[15] & ~(PAGE_SIZE - 1);
795 dump->u_tsize = (current->mm->end_code - dump->start_code) >> PAGE_SHIFT;
796 dump->u_dsize = (current->mm->brk + (PAGE_SIZE-1) - dump->start_data) >> PAGE_SHIFT;
797 dump->u_ssize = (current->mm->start_stack - dump->start_stack +
798 PAGE_SIZE - 1) >> PAGE_SHIFT;
799 /* Debug registers will come here. */
800
801 dump->regs = *regs;
802
803 dump->u_fpvalid = dump_fpu(regs, &dump->fpu);
804}
805
806asmlinkage int sys_fork(unsigned long r2, unsigned long r3,
807 unsigned long r4, unsigned long r5,
808 unsigned long r6, unsigned long r7,
809 struct pt_regs *pregs)
810{
811 return do_fork(SIGCHLD, pregs->regs[15], pregs, 0, 0, 0);
812}
813
814asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
815 unsigned long r4, unsigned long r5,
816 unsigned long r6, unsigned long r7,
817 struct pt_regs *pregs)
818{
819 if (!newsp)
820 newsp = pregs->regs[15];
821 return do_fork(clone_flags, newsp, pregs, 0, 0, 0);
822}
823
824/*
825 * This is trivial, and on the face of it looks like it
826 * could equally well be done in user mode.
827 *
828 * Not so, for quite unobvious reasons - register pressure.
829 * In user mode vfork() cannot have a stack frame, and if
830 * done by calling the "clone()" system call directly, you
831 * do not have enough call-clobbered registers to hold all
832 * the information you need.
833 */
834asmlinkage int sys_vfork(unsigned long r2, unsigned long r3,
835 unsigned long r4, unsigned long r5,
836 unsigned long r6, unsigned long r7,
837 struct pt_regs *pregs)
838{
839 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, pregs->regs[15], pregs, 0, 0, 0);
840}
841
842/*
843 * sys_execve() executes a new program.
844 */
845asmlinkage int sys_execve(char *ufilename, char **uargv,
846 char **uenvp, unsigned long r5,
847 unsigned long r6, unsigned long r7,
848 struct pt_regs *pregs)
849{
850 int error;
851 char *filename;
852
853 lock_kernel();
854 filename = getname((char __user *)ufilename);
855 error = PTR_ERR(filename);
856 if (IS_ERR(filename))
857 goto out;
858
859 error = do_execve(filename,
860 (char __user * __user *)uargv,
861 (char __user * __user *)uenvp,
862 pregs);
863 if (error == 0) {
864 task_lock(current);
865 current->ptrace &= ~PT_DTRACE;
866 task_unlock(current);
867 }
868 putname(filename);
869out:
870 unlock_kernel();
871 return error;
872}
873
874/*
875 * These bracket the sleeping functions..
876 */
877extern void interruptible_sleep_on(wait_queue_head_t *q);
878
879#define mid_sched ((unsigned long) interruptible_sleep_on)
880
881static int in_sh64_switch_to(unsigned long pc)
882{
883 extern char __sh64_switch_to_end;
884 /* For a sleeping task, the PC is somewhere in the middle of the function,
885 so we don't have to worry about masking the LSB off */
886 return (pc >= (unsigned long) sh64_switch_to) &&
887 (pc < (unsigned long) &__sh64_switch_to_end);
888}
889
890unsigned long get_wchan(struct task_struct *p)
891{
892 unsigned long schedule_fp;
893 unsigned long sh64_switch_to_fp;
894 unsigned long schedule_caller_pc;
895 unsigned long pc;
896
897 if (!p || p == current || p->state == TASK_RUNNING)
898 return 0;
899
900 /*
901 * The same comment as on the Alpha applies here, too ...
902 */
903 pc = thread_saved_pc(p);
904
905#ifdef CONFIG_FRAME_POINTER
906 if (in_sh64_switch_to(pc)) {
907 sh64_switch_to_fp = (long) p->thread.sp;
908 /* r14 is saved at offset 4 in the sh64_switch_to frame */
909 schedule_fp = *(unsigned long *) (long)(sh64_switch_to_fp + 4);
910
911 /* and the caller of 'schedule' is (currently!) saved at offset 24
912 in the frame of schedule (from disasm) */
913 schedule_caller_pc = *(unsigned long *) (long)(schedule_fp + 24);
914 return schedule_caller_pc;
915 }
916#endif
917 return pc;
918}
919
920/* Provide a /proc/asids file that lists out the
921 ASIDs currently associated with the processes. (If the DM.PC register is
922 examined through the debug link, this shows ASID + PC. To make use of this,
923 the PID->ASID relationship needs to be known. This is primarily for
924 debugging.)
925 */
926
927#if defined(CONFIG_SH64_PROC_ASIDS)
928#include <linux/init.h>
929#include <linux/proc_fs.h>
930
931static int
932asids_proc_info(char *buf, char **start, off_t fpos, int length, int *eof, void *data)
933{
934 int len=0;
935 struct task_struct *p;
936 read_lock(&tasklist_lock);
937 for_each_process(p) {
938 int pid = p->pid;
939 struct mm_struct *mm;
940 if (!pid) continue;
941 mm = p->mm;
942 if (mm) {
943 unsigned long asid, context;
944 context = mm->context;
945 asid = (context & 0xff);
946 len += sprintf(buf+len, "%5d : %02lx\n", pid, asid);
947 } else {
948 len += sprintf(buf+len, "%5d : (none)\n", pid);
949 }
950 }
951 read_unlock(&tasklist_lock);
952 *eof = 1;
953 return len;
954}
955
956static int __init register_proc_asids(void)
957{
958 create_proc_read_entry("asids", 0, NULL, asids_proc_info, NULL);
959 return 0;
960}
961
962__initcall(register_proc_asids);
963#endif
964
Linux 6.x block layer and io_uring tree(s)