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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/alpha/kernel/process.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/alpha/kernel/process.c')
-rw-r--r--arch/alpha/kernel/process.c528
1 files changed, 528 insertions, 0 deletions
diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
new file mode 100644
index 000000000000..4933f3ce5833
--- /dev/null
+++ b/arch/alpha/kernel/process.c
@@ -0,0 +1,528 @@
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
46void default_idle(void)
47{
48 barrier();
49}
50
51void
52cpu_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
66struct halt_info {
67 int mode;
68 char *restart_cmd;
69};
70
71static void
72common_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
153static void
154common_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
162void
163machine_restart(char *restart_cmd)
164{
165 common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd);
166}
167
168EXPORT_SYMBOL(machine_restart);
169
170void
171machine_halt(void)
172{
173 common_shutdown(LINUX_REBOOT_CMD_HALT, NULL);
174}
175
176EXPORT_SYMBOL(machine_halt);
177
178void
179machine_power_off(void)
180{
181 common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL);
182}
183
184EXPORT_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
189void
190show_regs(struct pt_regs *regs)
191{
192 dik_show_regs(regs, NULL);
193}
194
195/*
196 * Re-start a thread when doing execve()
197 */
198void
199start_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 */
210void
211exit_thread(void)
212{
213}
214
215void
216flush_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
227void
228release_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 */
241int
242alpha_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
252int
253alpha_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
270int
271copy_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 */
320void
321dump_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 */
381void
382dump_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
426int
427dump_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
440int
441dump_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 */
459asmlinkage int
460do_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);
472out:
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
490unsigned long
491thread_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
505unsigned long
506get_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}