2 * arch/s390/kernel/process.c
5 * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7 * Hartmut Penner (hp@de.ibm.com),
8 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
10 * Derived from "arch/i386/kernel/process.c"
11 * Copyright (C) 1995, Linus Torvalds
15 * This file handles the architecture-dependent parts of process handling..
18 #include <linux/compiler.h>
19 #include <linux/cpu.h>
20 #include <linux/errno.h>
21 #include <linux/sched.h>
22 #include <linux/kernel.h>
25 #include <linux/smp.h>
26 #include <linux/stddef.h>
27 #include <linux/unistd.h>
28 #include <linux/ptrace.h>
29 #include <linux/slab.h>
30 #include <linux/vmalloc.h>
31 #include <linux/user.h>
32 #include <linux/interrupt.h>
33 #include <linux/delay.h>
34 #include <linux/reboot.h>
35 #include <linux/init.h>
36 #include <linux/module.h>
37 #include <linux/notifier.h>
38 #include <linux/utsname.h>
39 #include <linux/tick.h>
40 #include <linux/elfcore.h>
41 #include <asm/uaccess.h>
42 #include <asm/pgtable.h>
43 #include <asm/system.h>
45 #include <asm/processor.h>
47 #include <asm/timer.h>
51 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
54 * Return saved PC of a blocked thread. used in kernel/sched.
55 * resume in entry.S does not create a new stack frame, it
56 * just stores the registers %r6-%r15 to the frame given by
57 * schedule. We want to return the address of the caller of
58 * schedule, so we have to walk the backchain one time to
59 * find the frame schedule() store its return address.
61 unsigned long thread_saved_pc(struct task_struct *tsk)
63 struct stack_frame *sf, *low, *high;
65 if (!tsk || !task_stack_page(tsk))
67 low = task_stack_page(tsk);
68 high = (struct stack_frame *) task_pt_regs(tsk);
69 sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
70 if (sf <= low || sf > high)
72 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
73 if (sf <= low || sf > high)
78 DEFINE_PER_CPU(struct s390_idle_data, s390_idle) = {
79 .lock = __SPIN_LOCK_UNLOCKED(s390_idle.lock)
82 static int s390_idle_enter(void)
84 struct s390_idle_data *idle;
86 idle = &__get_cpu_var(s390_idle);
87 spin_lock(&idle->lock);
90 idle->idle_enter = get_clock();
91 spin_unlock(&idle->lock);
92 vtime_stop_cpu_timer();
96 void s390_idle_leave(void)
98 struct s390_idle_data *idle;
100 vtime_start_cpu_timer();
101 idle = &__get_cpu_var(s390_idle);
102 spin_lock(&idle->lock);
103 idle->idle_time += get_clock() - idle->idle_enter;
105 spin_unlock(&idle->lock);
108 extern void s390_handle_mcck(void);
110 * The idle loop on a S390...
112 static void default_idle(void)
114 /* CPU is going idle. */
116 if (need_resched()) {
120 if (s390_idle_enter() == NOTIFY_BAD) {
124 #ifdef CONFIG_HOTPLUG_CPU
125 if (cpu_is_offline(smp_processor_id())) {
126 preempt_enable_no_resched();
130 local_mcck_disable();
131 if (test_thread_flag(TIF_MCCK_PENDING)) {
139 /* Wait for external, I/O or machine check interrupt. */
140 __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
141 PSW_MASK_IO | PSW_MASK_EXT);
147 tick_nohz_stop_sched_tick(1);
148 while (!need_resched())
150 tick_nohz_restart_sched_tick();
151 preempt_enable_no_resched();
157 extern void kernel_thread_starter(void);
161 "kernel_thread_starter:\n"
167 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
171 memset(®s, 0, sizeof(regs));
172 regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
173 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
174 regs.gprs[9] = (unsigned long) fn;
175 regs.gprs[10] = (unsigned long) arg;
176 regs.gprs[11] = (unsigned long) do_exit;
179 /* Ok, create the new process.. */
180 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
181 0, ®s, 0, NULL, NULL);
185 * Free current thread data structures etc..
187 void exit_thread(void)
191 void flush_thread(void)
194 clear_tsk_thread_flag(current, TIF_USEDFPU);
197 void release_thread(struct task_struct *dead_task)
201 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
202 unsigned long unused,
203 struct task_struct * p, struct pt_regs * regs)
207 struct stack_frame sf;
208 struct pt_regs childregs;
211 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
212 p->thread.ksp = (unsigned long) frame;
213 /* Store access registers to kernel stack of new process. */
214 frame->childregs = *regs;
215 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
216 frame->childregs.gprs[15] = new_stackp;
217 frame->sf.back_chain = 0;
219 /* new return point is ret_from_fork */
220 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
222 /* fake return stack for resume(), don't go back to schedule */
223 frame->sf.gprs[9] = (unsigned long) frame;
225 /* Save access registers to new thread structure. */
226 save_access_regs(&p->thread.acrs[0]);
230 * save fprs to current->thread.fp_regs to merge them with
231 * the emulated registers and then copy the result to the child.
233 save_fp_regs(¤t->thread.fp_regs);
234 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
235 sizeof(s390_fp_regs));
236 /* Set a new TLS ? */
237 if (clone_flags & CLONE_SETTLS)
238 p->thread.acrs[0] = regs->gprs[6];
239 #else /* CONFIG_64BIT */
240 /* Save the fpu registers to new thread structure. */
241 save_fp_regs(&p->thread.fp_regs);
242 /* Set a new TLS ? */
243 if (clone_flags & CLONE_SETTLS) {
244 if (test_thread_flag(TIF_31BIT)) {
245 p->thread.acrs[0] = (unsigned int) regs->gprs[6];
247 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
248 p->thread.acrs[1] = (unsigned int) regs->gprs[6];
251 #endif /* CONFIG_64BIT */
252 /* start new process with ar4 pointing to the correct address space */
253 p->thread.mm_segment = get_fs();
254 /* Don't copy debug registers */
255 memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
260 asmlinkage long sys_fork(void)
262 struct pt_regs *regs = task_pt_regs(current);
263 return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
266 asmlinkage long sys_clone(void)
268 struct pt_regs *regs = task_pt_regs(current);
269 unsigned long clone_flags;
271 int __user *parent_tidptr, *child_tidptr;
273 clone_flags = regs->gprs[3];
274 newsp = regs->orig_gpr2;
275 parent_tidptr = (int __user *) regs->gprs[4];
276 child_tidptr = (int __user *) regs->gprs[5];
278 newsp = regs->gprs[15];
279 return do_fork(clone_flags, newsp, regs, 0,
280 parent_tidptr, child_tidptr);
284 * This is trivial, and on the face of it looks like it
285 * could equally well be done in user mode.
287 * Not so, for quite unobvious reasons - register pressure.
288 * In user mode vfork() cannot have a stack frame, and if
289 * done by calling the "clone()" system call directly, you
290 * do not have enough call-clobbered registers to hold all
291 * the information you need.
293 asmlinkage long sys_vfork(void)
295 struct pt_regs *regs = task_pt_regs(current);
296 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
297 regs->gprs[15], regs, 0, NULL, NULL);
300 asmlinkage void execve_tail(void)
303 current->ptrace &= ~PT_DTRACE;
304 task_unlock(current);
305 current->thread.fp_regs.fpc = 0;
306 if (MACHINE_HAS_IEEE)
307 asm volatile("sfpc %0,%0" : : "d" (0));
311 * sys_execve() executes a new program.
313 asmlinkage long sys_execve(void)
315 struct pt_regs *regs = task_pt_regs(current);
317 unsigned long result;
320 filename = getname((char __user *) regs->orig_gpr2);
321 if (IS_ERR(filename)) {
322 result = PTR_ERR(filename);
325 rc = do_execve(filename, (char __user * __user *) regs->gprs[3],
326 (char __user * __user *) regs->gprs[4], regs);
332 result = regs->gprs[2];
340 * fill in the FPU structure for a core dump.
342 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
346 * save fprs to current->thread.fp_regs to merge them with
347 * the emulated registers and then copy the result to the dump.
349 save_fp_regs(¤t->thread.fp_regs);
350 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
351 #else /* CONFIG_64BIT */
352 save_fp_regs(fpregs);
353 #endif /* CONFIG_64BIT */
357 unsigned long get_wchan(struct task_struct *p)
359 struct stack_frame *sf, *low, *high;
360 unsigned long return_address;
363 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
365 low = task_stack_page(p);
366 high = (struct stack_frame *) task_pt_regs(p);
367 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
368 if (sf <= low || sf > high)
370 for (count = 0; count < 16; count++) {
371 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
372 if (sf <= low || sf > high)
374 return_address = sf->gprs[8] & PSW_ADDR_INSN;
375 if (!in_sched_functions(return_address))
376 return return_address;