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 set_thread_flag(TIF_POLLING_NRFLAG);
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];