2 * linux/arch/alpha/kernel/process.c
4 * Copyright (C) 1995 Linus Torvalds
8 * This file handles the architecture-dependent parts of process handling.
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/sched.h>
14 #include <linux/kernel.h>
16 #include <linux/smp.h>
17 #include <linux/stddef.h>
18 #include <linux/unistd.h>
19 #include <linux/ptrace.h>
20 #include <linux/user.h>
21 #include <linux/time.h>
22 #include <linux/major.h>
23 #include <linux/stat.h>
25 #include <linux/mman.h>
26 #include <linux/elfcore.h>
27 #include <linux/reboot.h>
28 #include <linux/tty.h>
29 #include <linux/console.h>
30 #include <linux/slab.h>
31 #include <linux/rcupdate.h>
34 #include <asm/uaccess.h>
36 #include <asm/pgtable.h>
37 #include <asm/hwrpb.h>
44 * Power off function, if any
46 void (*pm_power_off
)(void) = machine_power_off
;
47 EXPORT_SYMBOL(pm_power_off
);
52 current_thread_info()->status
|= TS_POLLING
;
55 /* FIXME -- EV6 and LCA45 know how to power down
59 while (!need_resched())
63 schedule_preempt_disabled();
74 common_shutdown_1(void *generic_ptr
)
76 struct halt_info
*how
= (struct halt_info
*)generic_ptr
;
77 struct percpu_struct
*cpup
;
78 unsigned long *pflags
, flags
;
79 int cpuid
= smp_processor_id();
81 /* No point in taking interrupts anymore. */
84 cpup
= (struct percpu_struct
*)
85 ((unsigned long)hwrpb
+ hwrpb
->processor_offset
86 + hwrpb
->processor_size
* cpuid
);
87 pflags
= &cpup
->flags
;
90 /* Clear reason to "default"; clear "bootstrap in progress". */
91 flags
&= ~0x00ff0001UL
;
94 /* Secondaries halt here. */
95 if (cpuid
!= boot_cpuid
) {
96 flags
|= 0x00040000UL
; /* "remain halted" */
98 set_cpu_present(cpuid
, false);
99 set_cpu_possible(cpuid
, false);
104 if (how
->mode
== LINUX_REBOOT_CMD_RESTART
) {
105 if (!how
->restart_cmd
) {
106 flags
|= 0x00020000UL
; /* "cold bootstrap" */
108 /* For SRM, we could probably set environment
109 variables to get this to work. We'd have to
110 delay this until after srm_paging_stop unless
111 we ever got srm_fixup working.
113 At the moment, SRM will use the last boot device,
114 but the file and flags will be the defaults, when
115 doing a "warm" bootstrap. */
116 flags
|= 0x00030000UL
; /* "warm bootstrap" */
119 flags
|= 0x00040000UL
; /* "remain halted" */
124 /* Wait for the secondaries to halt. */
125 set_cpu_present(boot_cpuid
, false);
126 set_cpu_possible(boot_cpuid
, false);
127 while (cpumask_weight(cpu_present_mask
))
131 /* If booted from SRM, reset some of the original environment. */
132 if (alpha_using_srm
) {
133 #ifdef CONFIG_DUMMY_CONSOLE
134 /* If we've gotten here after SysRq-b, leave interrupt
135 context before taking over the console. */
138 /* This has the effect of resetting the VGA video origin. */
139 take_over_console(&dummy_con
, 0, MAX_NR_CONSOLES
-1, 1);
141 pci_restore_srm_config();
145 if (alpha_mv
.kill_arch
)
146 alpha_mv
.kill_arch(how
->mode
);
148 if (! alpha_using_srm
&& how
->mode
!= LINUX_REBOOT_CMD_RESTART
) {
149 /* Unfortunately, since MILO doesn't currently understand
150 the hwrpb bits above, we can't reliably halt the
151 processor and keep it halted. So just loop. */
162 common_shutdown(int mode
, char *restart_cmd
)
164 struct halt_info args
;
166 args
.restart_cmd
= restart_cmd
;
167 on_each_cpu(common_shutdown_1
, &args
, 0);
171 machine_restart(char *restart_cmd
)
173 common_shutdown(LINUX_REBOOT_CMD_RESTART
, restart_cmd
);
180 common_shutdown(LINUX_REBOOT_CMD_HALT
, NULL
);
185 machine_power_off(void)
187 common_shutdown(LINUX_REBOOT_CMD_POWER_OFF
, NULL
);
191 /* Used by sysrq-p, among others. I don't believe r9-r15 are ever
192 saved in the context it's used. */
195 show_regs(struct pt_regs
*regs
)
197 dik_show_regs(regs
, NULL
);
201 * Re-start a thread when doing execve()
204 start_thread(struct pt_regs
* regs
, unsigned long pc
, unsigned long sp
)
210 EXPORT_SYMBOL(start_thread
);
213 * Free current thread data structures etc..
223 /* Arrange for each exec'ed process to start off with a clean slate
224 with respect to the FPU. This is all exceptions disabled. */
225 current_thread_info()->ieee_state
= 0;
226 wrfpcr(FPCR_DYN_NORMAL
| ieee_swcr_to_fpcr(0));
228 /* Clean slate for TLS. */
229 current_thread_info()->pcb
.unique
= 0;
233 release_thread(struct task_struct
*dead_task
)
238 * "alpha_clone()".. By the time we get here, the
239 * non-volatile registers have also been saved on the
240 * stack. We do some ugly pointer stuff here.. (see
243 * Notice that "fork()" is implemented in terms of clone,
244 * with parameters (SIGCHLD, 0).
247 alpha_clone(unsigned long clone_flags
, unsigned long usp
,
248 int __user
*parent_tid
, int __user
*child_tid
,
249 unsigned long tls_value
, struct pt_regs
*regs
)
254 return do_fork(clone_flags
, usp
, regs
, 0, parent_tid
, child_tid
);
258 alpha_vfork(struct pt_regs
*regs
)
260 return do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
, rdusp(),
261 regs
, 0, NULL
, NULL
);
265 * Copy an alpha thread..
269 copy_thread(unsigned long clone_flags
, unsigned long usp
,
271 struct task_struct
* p
, struct pt_regs
* regs
)
273 extern void ret_from_fork(void);
274 extern void ret_from_kernel_thread(void);
276 struct thread_info
*childti
= task_thread_info(p
);
277 struct pt_regs
*childregs
= task_pt_regs(p
);
278 struct switch_stack
*childstack
, *stack
;
279 unsigned long settls
;
281 childstack
= ((struct switch_stack
*) childregs
) - 1;
282 if (unlikely(!regs
)) {
284 memset(childstack
, 0,
285 sizeof(struct switch_stack
) + sizeof(struct pt_regs
));
286 childstack
->r26
= (unsigned long) ret_from_kernel_thread
;
287 childstack
->r9
= usp
; /* function */
288 childstack
->r10
= arg
;
289 childregs
->hae
= alpha_mv
.hae_cache
,
290 childti
->pcb
.usp
= 0;
291 childti
->pcb
.ksp
= (unsigned long) childstack
;
292 childti
->pcb
.flags
= 1; /* set FEN, clear everything else */
299 childregs
->r20
= 1; /* OSF/1 has some strange fork() semantics. */
301 stack
= ((struct switch_stack
*) regs
) - 1;
302 *childstack
= *stack
;
303 childstack
->r26
= (unsigned long) ret_from_fork
;
304 childti
->pcb
.usp
= usp
;
305 childti
->pcb
.ksp
= (unsigned long) childstack
;
306 childti
->pcb
.flags
= 1; /* set FEN, clear everything else */
308 /* Set a new TLS for the child thread? Peek back into the
309 syscall arguments that we saved on syscall entry. Oops,
310 except we'd have clobbered it with the parent/child set
311 of r20. Read the saved copy. */
312 /* Note: if CLONE_SETTLS is not set, then we must inherit the
313 value from the parent, which will have been set by the block
314 copy in dup_task_struct. This is non-intuitive, but is
315 required for proper operation in the case of a threaded
316 application calling fork. */
317 if (clone_flags
& CLONE_SETTLS
)
318 childti
->pcb
.unique
= settls
;
324 * Fill in the user structure for a ELF core dump.
327 dump_elf_thread(elf_greg_t
*dest
, struct pt_regs
*pt
, struct thread_info
*ti
)
329 /* switch stack follows right below pt_regs: */
330 struct switch_stack
* sw
= ((struct switch_stack
*) pt
) - 1;
362 dest
[30] = ti
== current_thread_info() ? rdusp() : ti
->pcb
.usp
;
365 /* Once upon a time this was the PS value. Which is stupid
366 since that is always 8 for usermode. Usurped for the more
367 useful value of the thread's UNIQUE field. */
368 dest
[32] = ti
->pcb
.unique
;
370 EXPORT_SYMBOL(dump_elf_thread
);
373 dump_elf_task(elf_greg_t
*dest
, struct task_struct
*task
)
375 dump_elf_thread(dest
, task_pt_regs(task
), task_thread_info(task
));
378 EXPORT_SYMBOL(dump_elf_task
);
381 dump_elf_task_fp(elf_fpreg_t
*dest
, struct task_struct
*task
)
383 struct switch_stack
*sw
= (struct switch_stack
*)task_pt_regs(task
) - 1;
384 memcpy(dest
, sw
->fp
, 32 * 8);
387 EXPORT_SYMBOL(dump_elf_task_fp
);
390 * Return saved PC of a blocked thread. This assumes the frame
391 * pointer is the 6th saved long on the kernel stack and that the
392 * saved return address is the first long in the frame. This all
393 * holds provided the thread blocked through a call to schedule() ($15
394 * is the frame pointer in schedule() and $15 is saved at offset 48 by
395 * entry.S:do_switch_stack).
397 * Under heavy swap load I've seen this lose in an ugly way. So do
398 * some extra sanity checking on the ranges we expect these pointers
399 * to be in so that we can fail gracefully. This is just for ps after
404 thread_saved_pc(struct task_struct
*t
)
406 unsigned long base
= (unsigned long)task_stack_page(t
);
407 unsigned long fp
, sp
= task_thread_info(t
)->pcb
.ksp
;
409 if (sp
> base
&& sp
+6*8 < base
+ 16*1024) {
410 fp
= ((unsigned long*)sp
)[6];
411 if (fp
> sp
&& fp
< base
+ 16*1024)
412 return *(unsigned long *)fp
;
419 get_wchan(struct task_struct
*p
)
421 unsigned long schedule_frame
;
423 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
)
426 * This one depends on the frame size of schedule(). Do a
427 * "disass schedule" in gdb to find the frame size. Also, the
428 * code assumes that sleep_on() follows immediately after
429 * interruptible_sleep_on() and that add_timer() follows
430 * immediately after interruptible_sleep(). Ugly, isn't it?
431 * Maybe adding a wchan field to task_struct would be better,
435 pc
= thread_saved_pc(p
);
436 if (in_sched_functions(pc
)) {
437 schedule_frame
= ((unsigned long *)task_thread_info(p
)->pcb
.ksp
)[6];
438 return ((unsigned long *)schedule_frame
)[12];