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>
24 #include <linux/smp.h>
25 #include <linux/smp_lock.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/a.out.h>
33 #include <linux/interrupt.h>
34 #include <linux/delay.h>
35 #include <linux/reboot.h>
36 #include <linux/init.h>
37 #include <linux/module.h>
38 #include <linux/notifier.h>
40 #include <asm/uaccess.h>
41 #include <asm/pgtable.h>
42 #include <asm/system.h>
44 #include <asm/processor.h>
46 #include <asm/timer.h>
48 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
51 * Return saved PC of a blocked thread. used in kernel/sched.
52 * resume in entry.S does not create a new stack frame, it
53 * just stores the registers %r6-%r15 to the frame given by
54 * schedule. We want to return the address of the caller of
55 * schedule, so we have to walk the backchain one time to
56 * find the frame schedule() store its return address.
58 unsigned long thread_saved_pc(struct task_struct *tsk)
60 struct stack_frame *sf, *low, *high;
62 if (!tsk || !task_stack_page(tsk))
64 low = task_stack_page(tsk);
65 high = (struct stack_frame *) task_pt_regs(tsk);
66 sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
67 if (sf <= low || sf > high)
69 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
70 if (sf <= low || sf > high)
76 * Need to know about CPUs going idle?
78 static ATOMIC_NOTIFIER_HEAD(idle_chain);
80 int register_idle_notifier(struct notifier_block *nb)
82 return atomic_notifier_chain_register(&idle_chain, nb);
84 EXPORT_SYMBOL(register_idle_notifier);
86 int unregister_idle_notifier(struct notifier_block *nb)
88 return atomic_notifier_chain_unregister(&idle_chain, nb);
90 EXPORT_SYMBOL(unregister_idle_notifier);
92 void do_monitor_call(struct pt_regs *regs, long interruption_code)
94 /* disable monitor call class 0 */
95 __ctl_clear_bit(8, 15);
97 atomic_notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
98 (void *)(long) smp_processor_id());
101 extern void s390_handle_mcck(void);
103 * The idle loop on a S390...
105 static void default_idle(void)
109 /* CPU is going idle. */
110 cpu = smp_processor_id();
113 if (need_resched()) {
118 rc = atomic_notifier_call_chain(&idle_chain,
119 CPU_IDLE, (void *)(long) cpu);
120 if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
122 if (rc != NOTIFY_OK) {
127 /* enable monitor call class 0 */
128 __ctl_set_bit(8, 15);
130 #ifdef CONFIG_HOTPLUG_CPU
131 if (cpu_is_offline(cpu)) {
132 preempt_enable_no_resched();
137 local_mcck_disable();
138 if (test_thread_flag(TIF_MCCK_PENDING)) {
146 /* Wait for external, I/O or machine check interrupt. */
147 __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
148 PSW_MASK_IO | PSW_MASK_EXT);
154 while (!need_resched())
157 preempt_enable_no_resched();
163 void show_regs(struct pt_regs *regs)
165 struct task_struct *tsk = current;
167 printk("CPU: %d %s\n", task_thread_info(tsk)->cpu, print_tainted());
168 printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
169 current->comm, current->pid, (void *) tsk,
170 (void *) tsk->thread.ksp);
172 show_registers(regs);
173 /* Show stack backtrace if pt_regs is from kernel mode */
174 if (!(regs->psw.mask & PSW_MASK_PSTATE))
175 show_trace(NULL, (unsigned long *) regs->gprs[15]);
178 extern void kernel_thread_starter(void);
182 "kernel_thread_starter:\n"
188 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
192 memset(®s, 0, sizeof(regs));
193 regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
194 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
195 regs.gprs[9] = (unsigned long) fn;
196 regs.gprs[10] = (unsigned long) arg;
197 regs.gprs[11] = (unsigned long) do_exit;
200 /* Ok, create the new process.. */
201 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
202 0, ®s, 0, NULL, NULL);
206 * Free current thread data structures etc..
208 void exit_thread(void)
212 void flush_thread(void)
215 clear_tsk_thread_flag(current, TIF_USEDFPU);
218 void release_thread(struct task_struct *dead_task)
222 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
223 unsigned long unused,
224 struct task_struct * p, struct pt_regs * regs)
228 struct stack_frame sf;
229 struct pt_regs childregs;
232 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
233 p->thread.ksp = (unsigned long) frame;
234 /* Store access registers to kernel stack of new process. */
235 frame->childregs = *regs;
236 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
237 frame->childregs.gprs[15] = new_stackp;
238 frame->sf.back_chain = 0;
240 /* new return point is ret_from_fork */
241 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
243 /* fake return stack for resume(), don't go back to schedule */
244 frame->sf.gprs[9] = (unsigned long) frame;
246 /* Save access registers to new thread structure. */
247 save_access_regs(&p->thread.acrs[0]);
251 * save fprs to current->thread.fp_regs to merge them with
252 * the emulated registers and then copy the result to the child.
254 save_fp_regs(¤t->thread.fp_regs);
255 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
256 sizeof(s390_fp_regs));
257 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
258 /* Set a new TLS ? */
259 if (clone_flags & CLONE_SETTLS)
260 p->thread.acrs[0] = regs->gprs[6];
261 #else /* CONFIG_64BIT */
262 /* Save the fpu registers to new thread structure. */
263 save_fp_regs(&p->thread.fp_regs);
264 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
265 /* Set a new TLS ? */
266 if (clone_flags & CLONE_SETTLS) {
267 if (test_thread_flag(TIF_31BIT)) {
268 p->thread.acrs[0] = (unsigned int) regs->gprs[6];
270 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
271 p->thread.acrs[1] = (unsigned int) regs->gprs[6];
274 #endif /* CONFIG_64BIT */
275 /* start new process with ar4 pointing to the correct address space */
276 p->thread.mm_segment = get_fs();
277 /* Don't copy debug registers */
278 memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
283 asmlinkage long sys_fork(struct pt_regs regs)
285 return do_fork(SIGCHLD, regs.gprs[15], ®s, 0, NULL, NULL);
288 asmlinkage long sys_clone(struct pt_regs regs)
290 unsigned long clone_flags;
292 int __user *parent_tidptr, *child_tidptr;
294 clone_flags = regs.gprs[3];
295 newsp = regs.orig_gpr2;
296 parent_tidptr = (int __user *) regs.gprs[4];
297 child_tidptr = (int __user *) regs.gprs[5];
299 newsp = regs.gprs[15];
300 return do_fork(clone_flags, newsp, ®s, 0,
301 parent_tidptr, child_tidptr);
305 * This is trivial, and on the face of it looks like it
306 * could equally well be done in user mode.
308 * Not so, for quite unobvious reasons - register pressure.
309 * In user mode vfork() cannot have a stack frame, and if
310 * done by calling the "clone()" system call directly, you
311 * do not have enough call-clobbered registers to hold all
312 * the information you need.
314 asmlinkage long sys_vfork(struct pt_regs regs)
316 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
317 regs.gprs[15], ®s, 0, NULL, NULL);
321 * sys_execve() executes a new program.
323 asmlinkage long sys_execve(struct pt_regs regs)
328 filename = getname((char __user *) regs.orig_gpr2);
329 error = PTR_ERR(filename);
330 if (IS_ERR(filename))
332 error = do_execve(filename, (char __user * __user *) regs.gprs[3],
333 (char __user * __user *) regs.gprs[4], ®s);
336 current->ptrace &= ~PT_DTRACE;
337 task_unlock(current);
338 current->thread.fp_regs.fpc = 0;
339 if (MACHINE_HAS_IEEE)
340 asm volatile("sfpc %0,%0" : : "d" (0));
349 * fill in the FPU structure for a core dump.
351 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
355 * save fprs to current->thread.fp_regs to merge them with
356 * the emulated registers and then copy the result to the dump.
358 save_fp_regs(¤t->thread.fp_regs);
359 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
360 #else /* CONFIG_64BIT */
361 save_fp_regs(fpregs);
362 #endif /* CONFIG_64BIT */
366 unsigned long get_wchan(struct task_struct *p)
368 struct stack_frame *sf, *low, *high;
369 unsigned long return_address;
372 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
374 low = task_stack_page(p);
375 high = (struct stack_frame *) task_pt_regs(p);
376 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
377 if (sf <= low || sf > high)
379 for (count = 0; count < 16; count++) {
380 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
381 if (sf <= low || sf > high)
383 return_address = sf->gprs[8] & PSW_ADDR_INSN;
384 if (!in_sched_functions(return_address))
385 return return_address;