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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 | ||
1da177e4 LT |
11 | #include <linux/errno.h> |
12 | #include <linux/module.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/smp.h> | |
1da177e4 LT |
17 | #include <linux/stddef.h> |
18 | #include <linux/unistd.h> | |
19 | #include <linux/ptrace.h> | |
20 | #include <linux/slab.h> | |
21 | #include <linux/user.h> | |
1da177e4 LT |
22 | #include <linux/utsname.h> |
23 | #include <linux/time.h> | |
24 | #include <linux/major.h> | |
25 | #include <linux/stat.h> | |
a8f340e3 | 26 | #include <linux/vt.h> |
1da177e4 LT |
27 | #include <linux/mman.h> |
28 | #include <linux/elfcore.h> | |
29 | #include <linux/reboot.h> | |
30 | #include <linux/tty.h> | |
31 | #include <linux/console.h> | |
32 | ||
33 | #include <asm/reg.h> | |
34 | #include <asm/uaccess.h> | |
35 | #include <asm/system.h> | |
36 | #include <asm/io.h> | |
37 | #include <asm/pgtable.h> | |
38 | #include <asm/hwrpb.h> | |
39 | #include <asm/fpu.h> | |
40 | ||
41 | #include "proto.h" | |
42 | #include "pci_impl.h" | |
43 | ||
5e38291d EB |
44 | /* |
45 | * Power off function, if any | |
46 | */ | |
47 | void (*pm_power_off)(void) = machine_power_off; | |
89eb1693 | 48 | EXPORT_SYMBOL(pm_power_off); |
5e38291d | 49 | |
1da177e4 LT |
50 | void |
51 | cpu_idle(void) | |
52 | { | |
64c7c8f8 NP |
53 | set_thread_flag(TIF_POLLING_NRFLAG); |
54 | ||
1da177e4 | 55 | while (1) { |
1da177e4 LT |
56 | /* FIXME -- EV6 and LCA45 know how to power down |
57 | the CPU. */ | |
58 | ||
59 | while (!need_resched()) | |
64c7c8f8 | 60 | cpu_relax(); |
1da177e4 LT |
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; | |
1371be0f RR |
96 | set_cpu_present(cpuid, false); |
97 | set_cpu_possible(cpuid, false); | |
1da177e4 LT |
98 | halt(); |
99 | } | |
100 | #endif | |
101 | ||
102 | if (how->mode == LINUX_REBOOT_CMD_RESTART) { | |
103 | if (!how->restart_cmd) { | |
104 | flags |= 0x00020000UL; /* "cold bootstrap" */ | |
105 | } else { | |
106 | /* For SRM, we could probably set environment | |
107 | variables to get this to work. We'd have to | |
108 | delay this until after srm_paging_stop unless | |
109 | we ever got srm_fixup working. | |
110 | ||
111 | At the moment, SRM will use the last boot device, | |
112 | but the file and flags will be the defaults, when | |
113 | doing a "warm" bootstrap. */ | |
114 | flags |= 0x00030000UL; /* "warm bootstrap" */ | |
115 | } | |
116 | } else { | |
117 | flags |= 0x00040000UL; /* "remain halted" */ | |
118 | } | |
119 | *pflags = flags; | |
120 | ||
121 | #ifdef CONFIG_SMP | |
122 | /* Wait for the secondaries to halt. */ | |
1371be0f RR |
123 | set_cpu_present(boot_cpuid, false); |
124 | set_cpu_possible(boot_cpuid, false); | |
c7d2d28b | 125 | while (cpus_weight(cpu_present_map)) |
1da177e4 LT |
126 | barrier(); |
127 | #endif | |
128 | ||
129 | /* If booted from SRM, reset some of the original environment. */ | |
130 | if (alpha_using_srm) { | |
131 | #ifdef CONFIG_DUMMY_CONSOLE | |
4b3c86a7 IK |
132 | /* If we've gotten here after SysRq-b, leave interrupt |
133 | context before taking over the console. */ | |
134 | if (in_interrupt()) | |
135 | irq_exit(); | |
1da177e4 LT |
136 | /* This has the effect of resetting the VGA video origin. */ |
137 | take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1); | |
138 | #endif | |
139 | pci_restore_srm_config(); | |
140 | set_hae(srm_hae); | |
141 | } | |
142 | ||
143 | if (alpha_mv.kill_arch) | |
144 | alpha_mv.kill_arch(how->mode); | |
145 | ||
146 | if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) { | |
147 | /* Unfortunately, since MILO doesn't currently understand | |
148 | the hwrpb bits above, we can't reliably halt the | |
149 | processor and keep it halted. So just loop. */ | |
150 | return; | |
151 | } | |
152 | ||
153 | if (alpha_using_srm) | |
154 | srm_paging_stop(); | |
155 | ||
156 | halt(); | |
157 | } | |
158 | ||
159 | static void | |
160 | common_shutdown(int mode, char *restart_cmd) | |
161 | { | |
162 | struct halt_info args; | |
163 | args.mode = mode; | |
164 | args.restart_cmd = restart_cmd; | |
15c8b6c1 | 165 | on_each_cpu(common_shutdown_1, &args, 0); |
1da177e4 LT |
166 | } |
167 | ||
168 | void | |
169 | machine_restart(char *restart_cmd) | |
170 | { | |
171 | common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd); | |
172 | } | |
173 | ||
1da177e4 LT |
174 | |
175 | void | |
176 | machine_halt(void) | |
177 | { | |
178 | common_shutdown(LINUX_REBOOT_CMD_HALT, NULL); | |
179 | } | |
180 | ||
1da177e4 LT |
181 | |
182 | void | |
183 | machine_power_off(void) | |
184 | { | |
185 | common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL); | |
186 | } | |
187 | ||
1da177e4 LT |
188 | |
189 | /* Used by sysrq-p, among others. I don't believe r9-r15 are ever | |
190 | saved in the context it's used. */ | |
191 | ||
192 | void | |
193 | show_regs(struct pt_regs *regs) | |
194 | { | |
195 | dik_show_regs(regs, NULL); | |
196 | } | |
197 | ||
198 | /* | |
199 | * Re-start a thread when doing execve() | |
200 | */ | |
201 | void | |
202 | start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) | |
203 | { | |
204 | set_fs(USER_DS); | |
205 | regs->pc = pc; | |
206 | regs->ps = 8; | |
207 | wrusp(sp); | |
208 | } | |
cff52daf | 209 | EXPORT_SYMBOL(start_thread); |
1da177e4 LT |
210 | |
211 | /* | |
212 | * Free current thread data structures etc.. | |
213 | */ | |
214 | void | |
215 | exit_thread(void) | |
216 | { | |
217 | } | |
218 | ||
219 | void | |
220 | flush_thread(void) | |
221 | { | |
222 | /* Arrange for each exec'ed process to start off with a clean slate | |
223 | with respect to the FPU. This is all exceptions disabled. */ | |
224 | current_thread_info()->ieee_state = 0; | |
225 | wrfpcr(FPCR_DYN_NORMAL | ieee_swcr_to_fpcr(0)); | |
226 | ||
227 | /* Clean slate for TLS. */ | |
228 | current_thread_info()->pcb.unique = 0; | |
229 | } | |
230 | ||
231 | void | |
232 | release_thread(struct task_struct *dead_task) | |
233 | { | |
234 | } | |
235 | ||
236 | /* | |
237 | * "alpha_clone()".. By the time we get here, the | |
238 | * non-volatile registers have also been saved on the | |
239 | * stack. We do some ugly pointer stuff here.. (see | |
240 | * also copy_thread) | |
241 | * | |
242 | * Notice that "fork()" is implemented in terms of clone, | |
243 | * with parameters (SIGCHLD, 0). | |
244 | */ | |
245 | int | |
246 | alpha_clone(unsigned long clone_flags, unsigned long usp, | |
247 | int __user *parent_tid, int __user *child_tid, | |
248 | unsigned long tls_value, struct pt_regs *regs) | |
249 | { | |
250 | if (!usp) | |
251 | usp = rdusp(); | |
252 | ||
253 | return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid); | |
254 | } | |
255 | ||
256 | int | |
257 | alpha_vfork(struct pt_regs *regs) | |
258 | { | |
259 | return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), | |
260 | regs, 0, NULL, NULL); | |
261 | } | |
262 | ||
263 | /* | |
264 | * Copy an alpha thread.. | |
265 | * | |
266 | * Note the "stack_offset" stuff: when returning to kernel mode, we need | |
267 | * to have some extra stack-space for the kernel stack that still exists | |
268 | * after the "ret_from_fork". When returning to user mode, we only want | |
269 | * the space needed by the syscall stack frame (ie "struct pt_regs"). | |
270 | * Use the passed "regs" pointer to determine how much space we need | |
271 | * for a kernel fork(). | |
272 | */ | |
273 | ||
274 | int | |
275 | copy_thread(int nr, unsigned long clone_flags, unsigned long usp, | |
276 | unsigned long unused, | |
277 | struct task_struct * p, struct pt_regs * regs) | |
278 | { | |
279 | extern void ret_from_fork(void); | |
280 | ||
27f45130 | 281 | struct thread_info *childti = task_thread_info(p); |
1da177e4 LT |
282 | struct pt_regs * childregs; |
283 | struct switch_stack * childstack, *stack; | |
284 | unsigned long stack_offset, settls; | |
285 | ||
286 | stack_offset = PAGE_SIZE - sizeof(struct pt_regs); | |
287 | if (!(regs->ps & 8)) | |
288 | stack_offset = (PAGE_SIZE-1) & (unsigned long) regs; | |
289 | childregs = (struct pt_regs *) | |
27f45130 | 290 | (stack_offset + PAGE_SIZE + task_stack_page(p)); |
1da177e4 LT |
291 | |
292 | *childregs = *regs; | |
293 | settls = regs->r20; | |
294 | childregs->r0 = 0; | |
295 | childregs->r19 = 0; | |
296 | childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */ | |
297 | regs->r20 = 0; | |
298 | stack = ((struct switch_stack *) regs) - 1; | |
299 | childstack = ((struct switch_stack *) childregs) - 1; | |
300 | *childstack = *stack; | |
301 | childstack->r26 = (unsigned long) ret_from_fork; | |
302 | childti->pcb.usp = usp; | |
303 | childti->pcb.ksp = (unsigned long) childstack; | |
304 | childti->pcb.flags = 1; /* set FEN, clear everything else */ | |
305 | ||
306 | /* Set a new TLS for the child thread? Peek back into the | |
307 | syscall arguments that we saved on syscall entry. Oops, | |
308 | except we'd have clobbered it with the parent/child set | |
309 | of r20. Read the saved copy. */ | |
310 | /* Note: if CLONE_SETTLS is not set, then we must inherit the | |
311 | value from the parent, which will have been set by the block | |
312 | copy in dup_task_struct. This is non-intuitive, but is | |
313 | required for proper operation in the case of a threaded | |
314 | application calling fork. */ | |
315 | if (clone_flags & CLONE_SETTLS) | |
316 | childti->pcb.unique = settls; | |
317 | ||
318 | return 0; | |
319 | } | |
320 | ||
1da177e4 LT |
321 | /* |
322 | * Fill in the user structure for a ELF core dump. | |
323 | */ | |
324 | void | |
325 | dump_elf_thread(elf_greg_t *dest, struct pt_regs *pt, struct thread_info *ti) | |
326 | { | |
327 | /* switch stack follows right below pt_regs: */ | |
328 | struct switch_stack * sw = ((struct switch_stack *) pt) - 1; | |
329 | ||
330 | dest[ 0] = pt->r0; | |
331 | dest[ 1] = pt->r1; | |
332 | dest[ 2] = pt->r2; | |
333 | dest[ 3] = pt->r3; | |
334 | dest[ 4] = pt->r4; | |
335 | dest[ 5] = pt->r5; | |
336 | dest[ 6] = pt->r6; | |
337 | dest[ 7] = pt->r7; | |
338 | dest[ 8] = pt->r8; | |
339 | dest[ 9] = sw->r9; | |
340 | dest[10] = sw->r10; | |
341 | dest[11] = sw->r11; | |
342 | dest[12] = sw->r12; | |
343 | dest[13] = sw->r13; | |
344 | dest[14] = sw->r14; | |
345 | dest[15] = sw->r15; | |
346 | dest[16] = pt->r16; | |
347 | dest[17] = pt->r17; | |
348 | dest[18] = pt->r18; | |
349 | dest[19] = pt->r19; | |
350 | dest[20] = pt->r20; | |
351 | dest[21] = pt->r21; | |
352 | dest[22] = pt->r22; | |
353 | dest[23] = pt->r23; | |
354 | dest[24] = pt->r24; | |
355 | dest[25] = pt->r25; | |
356 | dest[26] = pt->r26; | |
357 | dest[27] = pt->r27; | |
358 | dest[28] = pt->r28; | |
359 | dest[29] = pt->gp; | |
360 | dest[30] = rdusp(); | |
361 | dest[31] = pt->pc; | |
362 | ||
363 | /* Once upon a time this was the PS value. Which is stupid | |
364 | since that is always 8 for usermode. Usurped for the more | |
365 | useful value of the thread's UNIQUE field. */ | |
366 | dest[32] = ti->pcb.unique; | |
367 | } | |
cff52daf | 368 | EXPORT_SYMBOL(dump_elf_thread); |
1da177e4 LT |
369 | |
370 | int | |
371 | dump_elf_task(elf_greg_t *dest, struct task_struct *task) | |
372 | { | |
e52f4ca2 | 373 | dump_elf_thread(dest, task_pt_regs(task), task_thread_info(task)); |
1da177e4 LT |
374 | return 1; |
375 | } | |
cff52daf | 376 | EXPORT_SYMBOL(dump_elf_task); |
1da177e4 LT |
377 | |
378 | int | |
379 | dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task) | |
380 | { | |
e52f4ca2 | 381 | struct switch_stack *sw = (struct switch_stack *)task_pt_regs(task) - 1; |
1da177e4 | 382 | memcpy(dest, sw->fp, 32 * 8); |
1da177e4 LT |
383 | return 1; |
384 | } | |
cff52daf | 385 | EXPORT_SYMBOL(dump_elf_task_fp); |
1da177e4 LT |
386 | |
387 | /* | |
388 | * sys_execve() executes a new program. | |
389 | */ | |
390 | asmlinkage int | |
391 | do_sys_execve(char __user *ufilename, char __user * __user *argv, | |
392 | char __user * __user *envp, struct pt_regs *regs) | |
393 | { | |
394 | int error; | |
395 | char *filename; | |
396 | ||
397 | filename = getname(ufilename); | |
398 | error = PTR_ERR(filename); | |
399 | if (IS_ERR(filename)) | |
400 | goto out; | |
401 | error = do_execve(filename, argv, envp, regs); | |
402 | putname(filename); | |
403 | out: | |
404 | return error; | |
405 | } | |
406 | ||
407 | /* | |
408 | * Return saved PC of a blocked thread. This assumes the frame | |
409 | * pointer is the 6th saved long on the kernel stack and that the | |
410 | * saved return address is the first long in the frame. This all | |
411 | * holds provided the thread blocked through a call to schedule() ($15 | |
412 | * is the frame pointer in schedule() and $15 is saved at offset 48 by | |
413 | * entry.S:do_switch_stack). | |
414 | * | |
415 | * Under heavy swap load I've seen this lose in an ugly way. So do | |
416 | * some extra sanity checking on the ranges we expect these pointers | |
417 | * to be in so that we can fail gracefully. This is just for ps after | |
418 | * all. -- r~ | |
419 | */ | |
420 | ||
421 | unsigned long | |
36c8b586 | 422 | thread_saved_pc(struct task_struct *t) |
1da177e4 | 423 | { |
27f45130 | 424 | unsigned long base = (unsigned long)task_stack_page(t); |
37bfbaf9 | 425 | unsigned long fp, sp = task_thread_info(t)->pcb.ksp; |
1da177e4 LT |
426 | |
427 | if (sp > base && sp+6*8 < base + 16*1024) { | |
428 | fp = ((unsigned long*)sp)[6]; | |
429 | if (fp > sp && fp < base + 16*1024) | |
430 | return *(unsigned long *)fp; | |
431 | } | |
432 | ||
433 | return 0; | |
434 | } | |
435 | ||
436 | unsigned long | |
437 | get_wchan(struct task_struct *p) | |
438 | { | |
439 | unsigned long schedule_frame; | |
440 | unsigned long pc; | |
441 | if (!p || p == current || p->state == TASK_RUNNING) | |
442 | return 0; | |
443 | /* | |
444 | * This one depends on the frame size of schedule(). Do a | |
445 | * "disass schedule" in gdb to find the frame size. Also, the | |
446 | * code assumes that sleep_on() follows immediately after | |
447 | * interruptible_sleep_on() and that add_timer() follows | |
448 | * immediately after interruptible_sleep(). Ugly, isn't it? | |
449 | * Maybe adding a wchan field to task_struct would be better, | |
450 | * after all... | |
451 | */ | |
452 | ||
453 | pc = thread_saved_pc(p); | |
454 | if (in_sched_functions(pc)) { | |
37bfbaf9 | 455 | schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6]; |
1da177e4 LT |
456 | return ((unsigned long *)schedule_frame)[12]; |
457 | } | |
458 | return pc; | |
459 | } |