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/config.h>
19 #include <linux/compiler.h>
20 #include <linux/cpu.h>
21 #include <linux/errno.h>
22 #include <linux/sched.h>
23 #include <linux/kernel.h>
25 #include <linux/smp.h>
26 #include <linux/smp_lock.h>
27 #include <linux/stddef.h>
28 #include <linux/unistd.h>
29 #include <linux/ptrace.h>
30 #include <linux/slab.h>
31 #include <linux/vmalloc.h>
32 #include <linux/user.h>
33 #include <linux/a.out.h>
34 #include <linux/interrupt.h>
35 #include <linux/delay.h>
36 #include <linux/reboot.h>
37 #include <linux/init.h>
38 #include <linux/module.h>
39 #include <linux/notifier.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>
49 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
52 * Return saved PC of a blocked thread. used in kernel/sched.
53 * resume in entry.S does not create a new stack frame, it
54 * just stores the registers %r6-%r15 to the frame given by
55 * schedule. We want to return the address of the caller of
56 * schedule, so we have to walk the backchain one time to
57 * find the frame schedule() store its return address.
59 unsigned long thread_saved_pc(struct task_struct *tsk)
61 struct stack_frame *sf;
63 sf = (struct stack_frame *) tsk->thread.ksp;
64 sf = (struct stack_frame *) sf->back_chain;
69 * Need to know about CPUs going idle?
71 static struct notifier_block *idle_chain;
73 int register_idle_notifier(struct notifier_block *nb)
75 return notifier_chain_register(&idle_chain, nb);
77 EXPORT_SYMBOL(register_idle_notifier);
79 int unregister_idle_notifier(struct notifier_block *nb)
81 return notifier_chain_unregister(&idle_chain, nb);
83 EXPORT_SYMBOL(unregister_idle_notifier);
85 void do_monitor_call(struct pt_regs *regs, long interruption_code)
87 /* disable monitor call class 0 */
88 __ctl_clear_bit(8, 15);
90 notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
91 (void *)(long) smp_processor_id());
95 * The idle loop on a S390...
97 void default_idle(void)
104 if (need_resched()) {
110 /* CPU is going idle. */
111 cpu = smp_processor_id();
112 rc = notifier_call_chain(&idle_chain, CPU_IDLE, (void *)(long) cpu);
113 if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
115 if (rc != NOTIFY_OK) {
120 /* enable monitor call class 0 */
121 __ctl_set_bit(8, 15);
123 #ifdef CONFIG_HOTPLUG_CPU
124 if (cpu_is_offline(smp_processor_id()))
129 * Wait for external, I/O or machine check interrupt and
130 * switch off machine check bit after the wait has ended.
132 wait_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK | PSW_MASK_WAIT |
133 PSW_MASK_IO | PSW_MASK_EXT;
134 #ifndef CONFIG_ARCH_S390X
137 "0: la %0,1f-0b(%0)\n"
141 "1: la %0,2f-1b(%0)\n"
147 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
148 #else /* CONFIG_ARCH_S390X */
158 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
159 #endif /* CONFIG_ARCH_S390X */
169 void show_regs(struct pt_regs *regs)
171 struct task_struct *tsk = current;
173 printk("CPU: %d %s\n", tsk->thread_info->cpu, print_tainted());
174 printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
175 current->comm, current->pid, (void *) tsk,
176 (void *) tsk->thread.ksp);
178 show_registers(regs);
179 /* Show stack backtrace if pt_regs is from kernel mode */
180 if (!(regs->psw.mask & PSW_MASK_PSTATE))
181 show_trace(0,(unsigned long *) regs->gprs[15]);
184 extern void kernel_thread_starter(void);
187 "kernel_thread_starter:\n"
193 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
197 memset(®s, 0, sizeof(regs));
198 regs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
199 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
200 regs.gprs[9] = (unsigned long) fn;
201 regs.gprs[10] = (unsigned long) arg;
202 regs.gprs[11] = (unsigned long) do_exit;
205 /* Ok, create the new process.. */
206 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
207 0, ®s, 0, NULL, NULL);
211 * Free current thread data structures etc..
213 void exit_thread(void)
217 void flush_thread(void)
220 current->used_math = 0;
221 clear_tsk_thread_flag(current, TIF_USEDFPU);
224 void release_thread(struct task_struct *dead_task)
228 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
229 unsigned long unused,
230 struct task_struct * p, struct pt_regs * regs)
234 struct stack_frame sf;
235 struct pt_regs childregs;
238 frame = ((struct fake_frame *)
239 (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
240 p->thread.ksp = (unsigned long) frame;
241 p->set_child_tid = p->clear_child_tid = NULL;
242 /* Store access registers to kernel stack of new process. */
243 frame->childregs = *regs;
244 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
245 frame->childregs.gprs[15] = new_stackp;
246 frame->sf.back_chain = 0;
248 /* new return point is ret_from_fork */
249 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
251 /* fake return stack for resume(), don't go back to schedule */
252 frame->sf.gprs[9] = (unsigned long) frame;
254 /* Save access registers to new thread structure. */
255 save_access_regs(&p->thread.acrs[0]);
257 #ifndef CONFIG_ARCH_S390X
259 * save fprs to current->thread.fp_regs to merge them with
260 * the emulated registers and then copy the result to the child.
262 save_fp_regs(¤t->thread.fp_regs);
263 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
264 sizeof(s390_fp_regs));
265 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
266 /* Set a new TLS ? */
267 if (clone_flags & CLONE_SETTLS)
268 p->thread.acrs[0] = regs->gprs[6];
269 #else /* CONFIG_ARCH_S390X */
270 /* Save the fpu registers to new thread structure. */
271 save_fp_regs(&p->thread.fp_regs);
272 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
273 /* Set a new TLS ? */
274 if (clone_flags & CLONE_SETTLS) {
275 if (test_thread_flag(TIF_31BIT)) {
276 p->thread.acrs[0] = (unsigned int) regs->gprs[6];
278 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
279 p->thread.acrs[1] = (unsigned int) regs->gprs[6];
282 #endif /* CONFIG_ARCH_S390X */
283 /* start new process with ar4 pointing to the correct address space */
284 p->thread.mm_segment = get_fs();
285 /* Don't copy debug registers */
286 memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
291 asmlinkage long sys_fork(struct pt_regs regs)
293 return do_fork(SIGCHLD, regs.gprs[15], ®s, 0, NULL, NULL);
296 asmlinkage long sys_clone(struct pt_regs regs)
298 unsigned long clone_flags;
300 int __user *parent_tidptr, *child_tidptr;
302 clone_flags = regs.gprs[3];
303 newsp = regs.orig_gpr2;
304 parent_tidptr = (int __user *) regs.gprs[4];
305 child_tidptr = (int __user *) regs.gprs[5];
307 newsp = regs.gprs[15];
308 return do_fork(clone_flags, newsp, ®s, 0,
309 parent_tidptr, child_tidptr);
313 * This is trivial, and on the face of it looks like it
314 * could equally well be done in user mode.
316 * Not so, for quite unobvious reasons - register pressure.
317 * In user mode vfork() cannot have a stack frame, and if
318 * done by calling the "clone()" system call directly, you
319 * do not have enough call-clobbered registers to hold all
320 * the information you need.
322 asmlinkage long sys_vfork(struct pt_regs regs)
324 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
325 regs.gprs[15], ®s, 0, NULL, NULL);
329 * sys_execve() executes a new program.
331 asmlinkage long sys_execve(struct pt_regs regs)
336 filename = getname((char __user *) regs.orig_gpr2);
337 error = PTR_ERR(filename);
338 if (IS_ERR(filename))
340 error = do_execve(filename, (char __user * __user *) regs.gprs[3],
341 (char __user * __user *) regs.gprs[4], ®s);
343 current->ptrace &= ~PT_DTRACE;
344 current->thread.fp_regs.fpc = 0;
345 if (MACHINE_HAS_IEEE)
346 asm volatile("sfpc %0,%0" : : "d" (0));
355 * fill in the FPU structure for a core dump.
357 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
359 #ifndef CONFIG_ARCH_S390X
361 * save fprs to current->thread.fp_regs to merge them with
362 * the emulated registers and then copy the result to the dump.
364 save_fp_regs(¤t->thread.fp_regs);
365 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
366 #else /* CONFIG_ARCH_S390X */
367 save_fp_regs(fpregs);
368 #endif /* CONFIG_ARCH_S390X */
373 * fill in the user structure for a core dump..
375 void dump_thread(struct pt_regs * regs, struct user * dump)
378 /* changed the size calculations - should hopefully work better. lbt */
379 dump->magic = CMAGIC;
380 dump->start_code = 0;
381 dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
382 dump->u_tsize = current->mm->end_code >> PAGE_SHIFT;
383 dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT;
384 dump->u_dsize -= dump->u_tsize;
386 if (dump->start_stack < TASK_SIZE)
387 dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT;
388 memcpy(&dump->regs, regs, sizeof(s390_regs));
389 dump_fpu (regs, &dump->regs.fp_regs);
390 dump->regs.per_info = current->thread.per_info;
393 unsigned long get_wchan(struct task_struct *p)
395 struct stack_frame *sf, *low, *high;
396 unsigned long return_address;
399 if (!p || p == current || p->state == TASK_RUNNING || !p->thread_info)
401 low = (struct stack_frame *) p->thread_info;
402 high = (struct stack_frame *)
403 ((unsigned long) p->thread_info + THREAD_SIZE) - 1;
404 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
405 if (sf <= low || sf > high)
407 for (count = 0; count < 16; count++) {
408 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
409 if (sf <= low || sf > high)
411 return_address = sf->gprs[8] & PSW_ADDR_INSN;
412 if (!in_sched_functions(return_address))
413 return return_address;