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1da177e4 LT |
1 | /* |
2 | * linux/arch/alpha/kernel/process.c | |
3 | * | |
4 | * Copyright (C) 1995 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * This file handles the architecture-dependent parts of process handling. | |
9 | */ | |
10 | ||
11 | #include <linux/config.h> | |
12 | #include <linux/errno.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/mm.h> | |
17 | #include <linux/smp.h> | |
18 | #include <linux/smp_lock.h> | |
19 | #include <linux/stddef.h> | |
20 | #include <linux/unistd.h> | |
21 | #include <linux/ptrace.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/user.h> | |
24 | #include <linux/a.out.h> | |
25 | #include <linux/utsname.h> | |
26 | #include <linux/time.h> | |
27 | #include <linux/major.h> | |
28 | #include <linux/stat.h> | |
29 | #include <linux/mman.h> | |
30 | #include <linux/elfcore.h> | |
31 | #include <linux/reboot.h> | |
32 | #include <linux/tty.h> | |
33 | #include <linux/console.h> | |
34 | ||
35 | #include <asm/reg.h> | |
36 | #include <asm/uaccess.h> | |
37 | #include <asm/system.h> | |
38 | #include <asm/io.h> | |
39 | #include <asm/pgtable.h> | |
40 | #include <asm/hwrpb.h> | |
41 | #include <asm/fpu.h> | |
42 | ||
43 | #include "proto.h" | |
44 | #include "pci_impl.h" | |
45 | ||
46 | void default_idle(void) | |
47 | { | |
48 | barrier(); | |
49 | } | |
50 | ||
51 | void | |
52 | cpu_idle(void) | |
53 | { | |
54 | while (1) { | |
55 | void (*idle)(void) = default_idle; | |
56 | /* FIXME -- EV6 and LCA45 know how to power down | |
57 | the CPU. */ | |
58 | ||
59 | while (!need_resched()) | |
60 | idle(); | |
61 | schedule(); | |
62 | } | |
63 | } | |
64 | ||
65 | ||
66 | struct halt_info { | |
67 | int mode; | |
68 | char *restart_cmd; | |
69 | }; | |
70 | ||
71 | static void | |
72 | common_shutdown_1(void *generic_ptr) | |
73 | { | |
74 | struct halt_info *how = (struct halt_info *)generic_ptr; | |
75 | struct percpu_struct *cpup; | |
76 | unsigned long *pflags, flags; | |
77 | int cpuid = smp_processor_id(); | |
78 | ||
79 | /* No point in taking interrupts anymore. */ | |
80 | local_irq_disable(); | |
81 | ||
82 | cpup = (struct percpu_struct *) | |
83 | ((unsigned long)hwrpb + hwrpb->processor_offset | |
84 | + hwrpb->processor_size * cpuid); | |
85 | pflags = &cpup->flags; | |
86 | flags = *pflags; | |
87 | ||
88 | /* Clear reason to "default"; clear "bootstrap in progress". */ | |
89 | flags &= ~0x00ff0001UL; | |
90 | ||
91 | #ifdef CONFIG_SMP | |
92 | /* Secondaries halt here. */ | |
93 | if (cpuid != boot_cpuid) { | |
94 | flags |= 0x00040000UL; /* "remain halted" */ | |
95 | *pflags = flags; | |
96 | clear_bit(cpuid, &cpu_present_mask); | |
97 | halt(); | |
98 | } | |
99 | #endif | |
100 | ||
101 | if (how->mode == LINUX_REBOOT_CMD_RESTART) { | |
102 | if (!how->restart_cmd) { | |
103 | flags |= 0x00020000UL; /* "cold bootstrap" */ | |
104 | } else { | |
105 | /* For SRM, we could probably set environment | |
106 | variables to get this to work. We'd have to | |
107 | delay this until after srm_paging_stop unless | |
108 | we ever got srm_fixup working. | |
109 | ||
110 | At the moment, SRM will use the last boot device, | |
111 | but the file and flags will be the defaults, when | |
112 | doing a "warm" bootstrap. */ | |
113 | flags |= 0x00030000UL; /* "warm bootstrap" */ | |
114 | } | |
115 | } else { | |
116 | flags |= 0x00040000UL; /* "remain halted" */ | |
117 | } | |
118 | *pflags = flags; | |
119 | ||
120 | #ifdef CONFIG_SMP | |
121 | /* Wait for the secondaries to halt. */ | |
122 | cpu_clear(boot_cpuid, cpu_possible_map); | |
123 | while (cpus_weight(cpu_possible_map)) | |
124 | barrier(); | |
125 | #endif | |
126 | ||
127 | /* If booted from SRM, reset some of the original environment. */ | |
128 | if (alpha_using_srm) { | |
129 | #ifdef CONFIG_DUMMY_CONSOLE | |
130 | /* This has the effect of resetting the VGA video origin. */ | |
131 | take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1); | |
132 | #endif | |
133 | pci_restore_srm_config(); | |
134 | set_hae(srm_hae); | |
135 | } | |
136 | ||
137 | if (alpha_mv.kill_arch) | |
138 | alpha_mv.kill_arch(how->mode); | |
139 | ||
140 | if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) { | |
141 | /* Unfortunately, since MILO doesn't currently understand | |
142 | the hwrpb bits above, we can't reliably halt the | |
143 | processor and keep it halted. So just loop. */ | |
144 | return; | |
145 | } | |
146 | ||
147 | if (alpha_using_srm) | |
148 | srm_paging_stop(); | |
149 | ||
150 | halt(); | |
151 | } | |
152 | ||
153 | static void | |
154 | common_shutdown(int mode, char *restart_cmd) | |
155 | { | |
156 | struct halt_info args; | |
157 | args.mode = mode; | |
158 | args.restart_cmd = restart_cmd; | |
159 | on_each_cpu(common_shutdown_1, &args, 1, 0); | |
160 | } | |
161 | ||
162 | void | |
163 | machine_restart(char *restart_cmd) | |
164 | { | |
165 | common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd); | |
166 | } | |
167 | ||
168 | EXPORT_SYMBOL(machine_restart); | |
169 | ||
170 | void | |
171 | machine_halt(void) | |
172 | { | |
173 | common_shutdown(LINUX_REBOOT_CMD_HALT, NULL); | |
174 | } | |
175 | ||
176 | EXPORT_SYMBOL(machine_halt); | |
177 | ||
178 | void | |
179 | machine_power_off(void) | |
180 | { | |
181 | common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL); | |
182 | } | |
183 | ||
184 | EXPORT_SYMBOL(machine_power_off); | |
185 | ||
186 | /* Used by sysrq-p, among others. I don't believe r9-r15 are ever | |
187 | saved in the context it's used. */ | |
188 | ||
189 | void | |
190 | show_regs(struct pt_regs *regs) | |
191 | { | |
192 | dik_show_regs(regs, NULL); | |
193 | } | |
194 | ||
195 | /* | |
196 | * Re-start a thread when doing execve() | |
197 | */ | |
198 | void | |
199 | start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) | |
200 | { | |
201 | set_fs(USER_DS); | |
202 | regs->pc = pc; | |
203 | regs->ps = 8; | |
204 | wrusp(sp); | |
205 | } | |
206 | ||
207 | /* | |
208 | * Free current thread data structures etc.. | |
209 | */ | |
210 | void | |
211 | exit_thread(void) | |
212 | { | |
213 | } | |
214 | ||
215 | void | |
216 | flush_thread(void) | |
217 | { | |
218 | /* Arrange for each exec'ed process to start off with a clean slate | |
219 | with respect to the FPU. This is all exceptions disabled. */ | |
220 | current_thread_info()->ieee_state = 0; | |
221 | wrfpcr(FPCR_DYN_NORMAL | ieee_swcr_to_fpcr(0)); | |
222 | ||
223 | /* Clean slate for TLS. */ | |
224 | current_thread_info()->pcb.unique = 0; | |
225 | } | |
226 | ||
227 | void | |
228 | release_thread(struct task_struct *dead_task) | |
229 | { | |
230 | } | |
231 | ||
232 | /* | |
233 | * "alpha_clone()".. By the time we get here, the | |
234 | * non-volatile registers have also been saved on the | |
235 | * stack. We do some ugly pointer stuff here.. (see | |
236 | * also copy_thread) | |
237 | * | |
238 | * Notice that "fork()" is implemented in terms of clone, | |
239 | * with parameters (SIGCHLD, 0). | |
240 | */ | |
241 | int | |
242 | alpha_clone(unsigned long clone_flags, unsigned long usp, | |
243 | int __user *parent_tid, int __user *child_tid, | |
244 | unsigned long tls_value, struct pt_regs *regs) | |
245 | { | |
246 | if (!usp) | |
247 | usp = rdusp(); | |
248 | ||
249 | return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid); | |
250 | } | |
251 | ||
252 | int | |
253 | alpha_vfork(struct pt_regs *regs) | |
254 | { | |
255 | return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), | |
256 | regs, 0, NULL, NULL); | |
257 | } | |
258 | ||
259 | /* | |
260 | * Copy an alpha thread.. | |
261 | * | |
262 | * Note the "stack_offset" stuff: when returning to kernel mode, we need | |
263 | * to have some extra stack-space for the kernel stack that still exists | |
264 | * after the "ret_from_fork". When returning to user mode, we only want | |
265 | * the space needed by the syscall stack frame (ie "struct pt_regs"). | |
266 | * Use the passed "regs" pointer to determine how much space we need | |
267 | * for a kernel fork(). | |
268 | */ | |
269 | ||
270 | int | |
271 | copy_thread(int nr, unsigned long clone_flags, unsigned long usp, | |
272 | unsigned long unused, | |
273 | struct task_struct * p, struct pt_regs * regs) | |
274 | { | |
275 | extern void ret_from_fork(void); | |
276 | ||
277 | struct thread_info *childti = p->thread_info; | |
278 | struct pt_regs * childregs; | |
279 | struct switch_stack * childstack, *stack; | |
280 | unsigned long stack_offset, settls; | |
281 | ||
282 | stack_offset = PAGE_SIZE - sizeof(struct pt_regs); | |
283 | if (!(regs->ps & 8)) | |
284 | stack_offset = (PAGE_SIZE-1) & (unsigned long) regs; | |
285 | childregs = (struct pt_regs *) | |
286 | (stack_offset + PAGE_SIZE + (long) childti); | |
287 | ||
288 | *childregs = *regs; | |
289 | settls = regs->r20; | |
290 | childregs->r0 = 0; | |
291 | childregs->r19 = 0; | |
292 | childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */ | |
293 | regs->r20 = 0; | |
294 | stack = ((struct switch_stack *) regs) - 1; | |
295 | childstack = ((struct switch_stack *) childregs) - 1; | |
296 | *childstack = *stack; | |
297 | childstack->r26 = (unsigned long) ret_from_fork; | |
298 | childti->pcb.usp = usp; | |
299 | childti->pcb.ksp = (unsigned long) childstack; | |
300 | childti->pcb.flags = 1; /* set FEN, clear everything else */ | |
301 | ||
302 | /* Set a new TLS for the child thread? Peek back into the | |
303 | syscall arguments that we saved on syscall entry. Oops, | |
304 | except we'd have clobbered it with the parent/child set | |
305 | of r20. Read the saved copy. */ | |
306 | /* Note: if CLONE_SETTLS is not set, then we must inherit the | |
307 | value from the parent, which will have been set by the block | |
308 | copy in dup_task_struct. This is non-intuitive, but is | |
309 | required for proper operation in the case of a threaded | |
310 | application calling fork. */ | |
311 | if (clone_flags & CLONE_SETTLS) | |
312 | childti->pcb.unique = settls; | |
313 | ||
314 | return 0; | |
315 | } | |
316 | ||
317 | /* | |
318 | * Fill in the user structure for an ECOFF core dump. | |
319 | */ | |
320 | void | |
321 | dump_thread(struct pt_regs * pt, struct user * dump) | |
322 | { | |
323 | /* switch stack follows right below pt_regs: */ | |
324 | struct switch_stack * sw = ((struct switch_stack *) pt) - 1; | |
325 | ||
326 | dump->magic = CMAGIC; | |
327 | dump->start_code = current->mm->start_code; | |
328 | dump->start_data = current->mm->start_data; | |
329 | dump->start_stack = rdusp() & ~(PAGE_SIZE - 1); | |
330 | dump->u_tsize = ((current->mm->end_code - dump->start_code) | |
331 | >> PAGE_SHIFT); | |
332 | dump->u_dsize = ((current->mm->brk + PAGE_SIZE-1 - dump->start_data) | |
333 | >> PAGE_SHIFT); | |
334 | dump->u_ssize = (current->mm->start_stack - dump->start_stack | |
335 | + PAGE_SIZE-1) >> PAGE_SHIFT; | |
336 | ||
337 | /* | |
338 | * We store the registers in an order/format that is | |
339 | * compatible with DEC Unix/OSF/1 as this makes life easier | |
340 | * for gdb. | |
341 | */ | |
342 | dump->regs[EF_V0] = pt->r0; | |
343 | dump->regs[EF_T0] = pt->r1; | |
344 | dump->regs[EF_T1] = pt->r2; | |
345 | dump->regs[EF_T2] = pt->r3; | |
346 | dump->regs[EF_T3] = pt->r4; | |
347 | dump->regs[EF_T4] = pt->r5; | |
348 | dump->regs[EF_T5] = pt->r6; | |
349 | dump->regs[EF_T6] = pt->r7; | |
350 | dump->regs[EF_T7] = pt->r8; | |
351 | dump->regs[EF_S0] = sw->r9; | |
352 | dump->regs[EF_S1] = sw->r10; | |
353 | dump->regs[EF_S2] = sw->r11; | |
354 | dump->regs[EF_S3] = sw->r12; | |
355 | dump->regs[EF_S4] = sw->r13; | |
356 | dump->regs[EF_S5] = sw->r14; | |
357 | dump->regs[EF_S6] = sw->r15; | |
358 | dump->regs[EF_A3] = pt->r19; | |
359 | dump->regs[EF_A4] = pt->r20; | |
360 | dump->regs[EF_A5] = pt->r21; | |
361 | dump->regs[EF_T8] = pt->r22; | |
362 | dump->regs[EF_T9] = pt->r23; | |
363 | dump->regs[EF_T10] = pt->r24; | |
364 | dump->regs[EF_T11] = pt->r25; | |
365 | dump->regs[EF_RA] = pt->r26; | |
366 | dump->regs[EF_T12] = pt->r27; | |
367 | dump->regs[EF_AT] = pt->r28; | |
368 | dump->regs[EF_SP] = rdusp(); | |
369 | dump->regs[EF_PS] = pt->ps; | |
370 | dump->regs[EF_PC] = pt->pc; | |
371 | dump->regs[EF_GP] = pt->gp; | |
372 | dump->regs[EF_A0] = pt->r16; | |
373 | dump->regs[EF_A1] = pt->r17; | |
374 | dump->regs[EF_A2] = pt->r18; | |
375 | memcpy((char *)dump->regs + EF_SIZE, sw->fp, 32 * 8); | |
376 | } | |
377 | ||
378 | /* | |
379 | * Fill in the user structure for a ELF core dump. | |
380 | */ | |
381 | void | |
382 | dump_elf_thread(elf_greg_t *dest, struct pt_regs *pt, struct thread_info *ti) | |
383 | { | |
384 | /* switch stack follows right below pt_regs: */ | |
385 | struct switch_stack * sw = ((struct switch_stack *) pt) - 1; | |
386 | ||
387 | dest[ 0] = pt->r0; | |
388 | dest[ 1] = pt->r1; | |
389 | dest[ 2] = pt->r2; | |
390 | dest[ 3] = pt->r3; | |
391 | dest[ 4] = pt->r4; | |
392 | dest[ 5] = pt->r5; | |
393 | dest[ 6] = pt->r6; | |
394 | dest[ 7] = pt->r7; | |
395 | dest[ 8] = pt->r8; | |
396 | dest[ 9] = sw->r9; | |
397 | dest[10] = sw->r10; | |
398 | dest[11] = sw->r11; | |
399 | dest[12] = sw->r12; | |
400 | dest[13] = sw->r13; | |
401 | dest[14] = sw->r14; | |
402 | dest[15] = sw->r15; | |
403 | dest[16] = pt->r16; | |
404 | dest[17] = pt->r17; | |
405 | dest[18] = pt->r18; | |
406 | dest[19] = pt->r19; | |
407 | dest[20] = pt->r20; | |
408 | dest[21] = pt->r21; | |
409 | dest[22] = pt->r22; | |
410 | dest[23] = pt->r23; | |
411 | dest[24] = pt->r24; | |
412 | dest[25] = pt->r25; | |
413 | dest[26] = pt->r26; | |
414 | dest[27] = pt->r27; | |
415 | dest[28] = pt->r28; | |
416 | dest[29] = pt->gp; | |
417 | dest[30] = rdusp(); | |
418 | dest[31] = pt->pc; | |
419 | ||
420 | /* Once upon a time this was the PS value. Which is stupid | |
421 | since that is always 8 for usermode. Usurped for the more | |
422 | useful value of the thread's UNIQUE field. */ | |
423 | dest[32] = ti->pcb.unique; | |
424 | } | |
425 | ||
426 | int | |
427 | dump_elf_task(elf_greg_t *dest, struct task_struct *task) | |
428 | { | |
429 | struct thread_info *ti; | |
430 | struct pt_regs *pt; | |
431 | ||
432 | ti = task->thread_info; | |
433 | pt = (struct pt_regs *)((unsigned long)ti + 2*PAGE_SIZE) - 1; | |
434 | ||
435 | dump_elf_thread(dest, pt, ti); | |
436 | ||
437 | return 1; | |
438 | } | |
439 | ||
440 | int | |
441 | dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task) | |
442 | { | |
443 | struct thread_info *ti; | |
444 | struct pt_regs *pt; | |
445 | struct switch_stack *sw; | |
446 | ||
447 | ti = task->thread_info; | |
448 | pt = (struct pt_regs *)((unsigned long)ti + 2*PAGE_SIZE) - 1; | |
449 | sw = (struct switch_stack *)pt - 1; | |
450 | ||
451 | memcpy(dest, sw->fp, 32 * 8); | |
452 | ||
453 | return 1; | |
454 | } | |
455 | ||
456 | /* | |
457 | * sys_execve() executes a new program. | |
458 | */ | |
459 | asmlinkage int | |
460 | do_sys_execve(char __user *ufilename, char __user * __user *argv, | |
461 | char __user * __user *envp, struct pt_regs *regs) | |
462 | { | |
463 | int error; | |
464 | char *filename; | |
465 | ||
466 | filename = getname(ufilename); | |
467 | error = PTR_ERR(filename); | |
468 | if (IS_ERR(filename)) | |
469 | goto out; | |
470 | error = do_execve(filename, argv, envp, regs); | |
471 | putname(filename); | |
472 | out: | |
473 | return error; | |
474 | } | |
475 | ||
476 | /* | |
477 | * Return saved PC of a blocked thread. This assumes the frame | |
478 | * pointer is the 6th saved long on the kernel stack and that the | |
479 | * saved return address is the first long in the frame. This all | |
480 | * holds provided the thread blocked through a call to schedule() ($15 | |
481 | * is the frame pointer in schedule() and $15 is saved at offset 48 by | |
482 | * entry.S:do_switch_stack). | |
483 | * | |
484 | * Under heavy swap load I've seen this lose in an ugly way. So do | |
485 | * some extra sanity checking on the ranges we expect these pointers | |
486 | * to be in so that we can fail gracefully. This is just for ps after | |
487 | * all. -- r~ | |
488 | */ | |
489 | ||
490 | unsigned long | |
491 | thread_saved_pc(task_t *t) | |
492 | { | |
493 | unsigned long base = (unsigned long)t->thread_info; | |
494 | unsigned long fp, sp = t->thread_info->pcb.ksp; | |
495 | ||
496 | if (sp > base && sp+6*8 < base + 16*1024) { | |
497 | fp = ((unsigned long*)sp)[6]; | |
498 | if (fp > sp && fp < base + 16*1024) | |
499 | return *(unsigned long *)fp; | |
500 | } | |
501 | ||
502 | return 0; | |
503 | } | |
504 | ||
505 | unsigned long | |
506 | get_wchan(struct task_struct *p) | |
507 | { | |
508 | unsigned long schedule_frame; | |
509 | unsigned long pc; | |
510 | if (!p || p == current || p->state == TASK_RUNNING) | |
511 | return 0; | |
512 | /* | |
513 | * This one depends on the frame size of schedule(). Do a | |
514 | * "disass schedule" in gdb to find the frame size. Also, the | |
515 | * code assumes that sleep_on() follows immediately after | |
516 | * interruptible_sleep_on() and that add_timer() follows | |
517 | * immediately after interruptible_sleep(). Ugly, isn't it? | |
518 | * Maybe adding a wchan field to task_struct would be better, | |
519 | * after all... | |
520 | */ | |
521 | ||
522 | pc = thread_saved_pc(p); | |
523 | if (in_sched_functions(pc)) { | |
524 | schedule_frame = ((unsigned long *)p->thread_info->pcb.ksp)[6]; | |
525 | return ((unsigned long *)schedule_frame)[12]; | |
526 | } | |
527 | return pc; | |
528 | } |