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);
55 common_shutdown_1(void *generic_ptr)
57 struct halt_info *how = (struct halt_info *)generic_ptr;
58 struct percpu_struct *cpup;
59 unsigned long *pflags, flags;
60 int cpuid = smp_processor_id();
62 /* No point in taking interrupts anymore. */
65 cpup = (struct percpu_struct *)
66 ((unsigned long)hwrpb + hwrpb->processor_offset
67 + hwrpb->processor_size * cpuid);
68 pflags = &cpup->flags;
71 /* Clear reason to "default"; clear "bootstrap in progress". */
72 flags &= ~0x00ff0001UL;
75 /* Secondaries halt here. */
76 if (cpuid != boot_cpuid) {
77 flags |= 0x00040000UL; /* "remain halted" */
79 set_cpu_present(cpuid, false);
80 set_cpu_possible(cpuid, false);
85 if (how->mode == LINUX_REBOOT_CMD_RESTART) {
86 if (!how->restart_cmd) {
87 flags |= 0x00020000UL; /* "cold bootstrap" */
89 /* For SRM, we could probably set environment
90 variables to get this to work. We'd have to
91 delay this until after srm_paging_stop unless
92 we ever got srm_fixup working.
94 At the moment, SRM will use the last boot device,
95 but the file and flags will be the defaults, when
96 doing a "warm" bootstrap. */
97 flags |= 0x00030000UL; /* "warm bootstrap" */
100 flags |= 0x00040000UL; /* "remain halted" */
105 /* Wait for the secondaries to halt. */
106 set_cpu_present(boot_cpuid, false);
107 set_cpu_possible(boot_cpuid, false);
108 while (cpumask_weight(cpu_present_mask))
112 /* If booted from SRM, reset some of the original environment. */
113 if (alpha_using_srm) {
114 #ifdef CONFIG_DUMMY_CONSOLE
115 /* If we've gotten here after SysRq-b, leave interrupt
116 context before taking over the console. */
119 /* This has the effect of resetting the VGA video origin. */
120 take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1);
122 pci_restore_srm_config();
126 if (alpha_mv.kill_arch)
127 alpha_mv.kill_arch(how->mode);
129 if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) {
130 /* Unfortunately, since MILO doesn't currently understand
131 the hwrpb bits above, we can't reliably halt the
132 processor and keep it halted. So just loop. */
143 common_shutdown(int mode, char *restart_cmd)
145 struct halt_info args;
147 args.restart_cmd = restart_cmd;
148 on_each_cpu(common_shutdown_1, &args, 0);
152 machine_restart(char *restart_cmd)
154 common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd);
161 common_shutdown(LINUX_REBOOT_CMD_HALT, NULL);
166 machine_power_off(void)
168 common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL);
172 /* Used by sysrq-p, among others. I don't believe r9-r15 are ever
173 saved in the context it's used. */
176 show_regs(struct pt_regs *regs)
178 show_regs_print_info(KERN_DEFAULT);
179 dik_show_regs(regs, NULL);
183 * Re-start a thread when doing execve()
186 start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
192 EXPORT_SYMBOL(start_thread);
195 * Free current thread data structures etc..
205 /* Arrange for each exec'ed process to start off with a clean slate
206 with respect to the FPU. This is all exceptions disabled. */
207 current_thread_info()->ieee_state = 0;
208 wrfpcr(FPCR_DYN_NORMAL | ieee_swcr_to_fpcr(0));
210 /* Clean slate for TLS. */
211 current_thread_info()->pcb.unique = 0;
215 release_thread(struct task_struct *dead_task)
220 * Copy an alpha thread..
224 copy_thread(unsigned long clone_flags, unsigned long usp,
226 struct task_struct *p)
228 extern void ret_from_fork(void);
229 extern void ret_from_kernel_thread(void);
231 struct thread_info *childti = task_thread_info(p);
232 struct pt_regs *childregs = task_pt_regs(p);
233 struct pt_regs *regs = current_pt_regs();
234 struct switch_stack *childstack, *stack;
236 childstack = ((struct switch_stack *) childregs) - 1;
237 childti->pcb.ksp = (unsigned long) childstack;
238 childti->pcb.flags = 1; /* set FEN, clear everything else */
240 if (unlikely(p->flags & PF_KTHREAD)) {
242 memset(childstack, 0,
243 sizeof(struct switch_stack) + sizeof(struct pt_regs));
244 childstack->r26 = (unsigned long) ret_from_kernel_thread;
245 childstack->r9 = usp; /* function */
246 childstack->r10 = arg;
247 childregs->hae = alpha_mv.hae_cache,
248 childti->pcb.usp = 0;
251 /* Note: if CLONE_SETTLS is not set, then we must inherit the
252 value from the parent, which will have been set by the block
253 copy in dup_task_struct. This is non-intuitive, but is
254 required for proper operation in the case of a threaded
255 application calling fork. */
256 if (clone_flags & CLONE_SETTLS)
257 childti->pcb.unique = regs->r20;
258 childti->pcb.usp = usp ?: rdusp();
262 childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */
264 stack = ((struct switch_stack *) regs) - 1;
265 *childstack = *stack;
266 childstack->r26 = (unsigned long) ret_from_fork;
271 * Fill in the user structure for a ELF core dump.
274 dump_elf_thread(elf_greg_t *dest, struct pt_regs *pt, struct thread_info *ti)
276 /* switch stack follows right below pt_regs: */
277 struct switch_stack * sw = ((struct switch_stack *) pt) - 1;
309 dest[30] = ti == current_thread_info() ? rdusp() : ti->pcb.usp;
312 /* Once upon a time this was the PS value. Which is stupid
313 since that is always 8 for usermode. Usurped for the more
314 useful value of the thread's UNIQUE field. */
315 dest[32] = ti->pcb.unique;
317 EXPORT_SYMBOL(dump_elf_thread);
320 dump_elf_task(elf_greg_t *dest, struct task_struct *task)
322 dump_elf_thread(dest, task_pt_regs(task), task_thread_info(task));
325 EXPORT_SYMBOL(dump_elf_task);
328 dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task)
330 struct switch_stack *sw = (struct switch_stack *)task_pt_regs(task) - 1;
331 memcpy(dest, sw->fp, 32 * 8);
334 EXPORT_SYMBOL(dump_elf_task_fp);
337 * Return saved PC of a blocked thread. This assumes the frame
338 * pointer is the 6th saved long on the kernel stack and that the
339 * saved return address is the first long in the frame. This all
340 * holds provided the thread blocked through a call to schedule() ($15
341 * is the frame pointer in schedule() and $15 is saved at offset 48 by
342 * entry.S:do_switch_stack).
344 * Under heavy swap load I've seen this lose in an ugly way. So do
345 * some extra sanity checking on the ranges we expect these pointers
346 * to be in so that we can fail gracefully. This is just for ps after
351 thread_saved_pc(struct task_struct *t)
353 unsigned long base = (unsigned long)task_stack_page(t);
354 unsigned long fp, sp = task_thread_info(t)->pcb.ksp;
356 if (sp > base && sp+6*8 < base + 16*1024) {
357 fp = ((unsigned long*)sp)[6];
358 if (fp > sp && fp < base + 16*1024)
359 return *(unsigned long *)fp;
366 get_wchan(struct task_struct *p)
368 unsigned long schedule_frame;
370 if (!p || p == current || p->state == TASK_RUNNING)
373 * This one depends on the frame size of schedule(). Do a
374 * "disass schedule" in gdb to find the frame size. Also, the
375 * code assumes that sleep_on() follows immediately after
376 * interruptible_sleep_on() and that add_timer() follows
377 * immediately after interruptible_sleep(). Ugly, isn't it?
378 * Maybe adding a wchan field to task_struct would be better,
382 pc = thread_saved_pc(p);
383 if (in_sched_functions(pc)) {
384 schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6];
385 return ((unsigned long *)schedule_frame)[12];