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/sched/debug.h>
15 #include <linux/sched/task.h>
16 #include <linux/kernel.h>
18 #include <linux/smp.h>
19 #include <linux/stddef.h>
20 #include <linux/unistd.h>
21 #include <linux/ptrace.h>
22 #include <linux/user.h>
23 #include <linux/time.h>
24 #include <linux/major.h>
25 #include <linux/stat.h>
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 #include <linux/slab.h>
33 #include <linux/rcupdate.h>
36 #include <linux/uaccess.h>
38 #include <asm/pgtable.h>
39 #include <asm/hwrpb.h>
46 * Power off function, if any
48 void (*pm_power_off)(void) = machine_power_off;
49 EXPORT_SYMBOL(pm_power_off);
51 #ifdef CONFIG_ALPHA_WTINT
54 * EV6, LCA45 and QEMU know how to power down, skipping N timer interrupts.
56 void arch_cpu_idle(void)
62 void arch_cpu_idle_dead(void)
66 #endif /* ALPHA_WTINT */
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. */
140 do_take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1);
143 pci_restore_srm_config();
147 if (alpha_mv.kill_arch)
148 alpha_mv.kill_arch(how->mode);
150 if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) {
151 /* Unfortunately, since MILO doesn't currently understand
152 the hwrpb bits above, we can't reliably halt the
153 processor and keep it halted. So just loop. */
164 common_shutdown(int mode, char *restart_cmd)
166 struct halt_info args;
168 args.restart_cmd = restart_cmd;
169 on_each_cpu(common_shutdown_1, &args, 0);
173 machine_restart(char *restart_cmd)
175 common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd);
182 common_shutdown(LINUX_REBOOT_CMD_HALT, NULL);
187 machine_power_off(void)
189 common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL);
193 /* Used by sysrq-p, among others. I don't believe r9-r15 are ever
194 saved in the context it's used. */
197 show_regs(struct pt_regs *regs)
199 show_regs_print_info(KERN_DEFAULT);
200 dik_show_regs(regs, NULL);
204 * Re-start a thread when doing execve()
207 start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
213 EXPORT_SYMBOL(start_thread);
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));
223 /* Clean slate for TLS. */
224 current_thread_info()->pcb.unique = 0;
228 release_thread(struct task_struct *dead_task)
233 * Copy architecture-specific thread state
236 copy_thread(unsigned long clone_flags, unsigned long usp,
237 unsigned long kthread_arg,
238 struct task_struct *p)
240 extern void ret_from_fork(void);
241 extern void ret_from_kernel_thread(void);
243 struct thread_info *childti = task_thread_info(p);
244 struct pt_regs *childregs = task_pt_regs(p);
245 struct pt_regs *regs = current_pt_regs();
246 struct switch_stack *childstack, *stack;
248 childstack = ((struct switch_stack *) childregs) - 1;
249 childti->pcb.ksp = (unsigned long) childstack;
250 childti->pcb.flags = 1; /* set FEN, clear everything else */
252 if (unlikely(p->flags & PF_KTHREAD)) {
254 memset(childstack, 0,
255 sizeof(struct switch_stack) + sizeof(struct pt_regs));
256 childstack->r26 = (unsigned long) ret_from_kernel_thread;
257 childstack->r9 = usp; /* function */
258 childstack->r10 = kthread_arg;
259 childregs->hae = alpha_mv.hae_cache,
260 childti->pcb.usp = 0;
263 /* Note: if CLONE_SETTLS is not set, then we must inherit the
264 value from the parent, which will have been set by the block
265 copy in dup_task_struct. This is non-intuitive, but is
266 required for proper operation in the case of a threaded
267 application calling fork. */
268 if (clone_flags & CLONE_SETTLS)
269 childti->pcb.unique = regs->r20;
270 childti->pcb.usp = usp ?: rdusp();
274 childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */
276 stack = ((struct switch_stack *) regs) - 1;
277 *childstack = *stack;
278 childstack->r26 = (unsigned long) ret_from_fork;
283 * Fill in the user structure for a ELF core dump.
286 dump_elf_thread(elf_greg_t *dest, struct pt_regs *pt, struct thread_info *ti)
288 /* switch stack follows right below pt_regs: */
289 struct switch_stack * sw = ((struct switch_stack *) pt) - 1;
321 dest[30] = ti == current_thread_info() ? rdusp() : ti->pcb.usp;
324 /* Once upon a time this was the PS value. Which is stupid
325 since that is always 8 for usermode. Usurped for the more
326 useful value of the thread's UNIQUE field. */
327 dest[32] = ti->pcb.unique;
329 EXPORT_SYMBOL(dump_elf_thread);
332 dump_elf_task(elf_greg_t *dest, struct task_struct *task)
334 dump_elf_thread(dest, task_pt_regs(task), task_thread_info(task));
337 EXPORT_SYMBOL(dump_elf_task);
340 dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task)
342 struct switch_stack *sw = (struct switch_stack *)task_pt_regs(task) - 1;
343 memcpy(dest, sw->fp, 32 * 8);
346 EXPORT_SYMBOL(dump_elf_task_fp);
349 * Return saved PC of a blocked thread. This assumes the frame
350 * pointer is the 6th saved long on the kernel stack and that the
351 * saved return address is the first long in the frame. This all
352 * holds provided the thread blocked through a call to schedule() ($15
353 * is the frame pointer in schedule() and $15 is saved at offset 48 by
354 * entry.S:do_switch_stack).
356 * Under heavy swap load I've seen this lose in an ugly way. So do
357 * some extra sanity checking on the ranges we expect these pointers
358 * to be in so that we can fail gracefully. This is just for ps after
363 thread_saved_pc(struct task_struct *t)
365 unsigned long base = (unsigned long)task_stack_page(t);
366 unsigned long fp, sp = task_thread_info(t)->pcb.ksp;
368 if (sp > base && sp+6*8 < base + 16*1024) {
369 fp = ((unsigned long*)sp)[6];
370 if (fp > sp && fp < base + 16*1024)
371 return *(unsigned long *)fp;
378 get_wchan(struct task_struct *p)
380 unsigned long schedule_frame;
382 if (!p || p == current || p->state == TASK_RUNNING)
385 * This one depends on the frame size of schedule(). Do a
386 * "disass schedule" in gdb to find the frame size. Also, the
387 * code assumes that sleep_on() follows immediately after
388 * interruptible_sleep_on() and that add_timer() follows
389 * immediately after interruptible_sleep(). Ugly, isn't it?
390 * Maybe adding a wchan field to task_struct would be better,
394 pc = thread_saved_pc(p);
395 if (in_sched_functions(pc)) {
396 schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6];
397 return ((unsigned long *)schedule_frame)[12];