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)
63 bc = *((unsigned long *) tsk->thread.ksp);
64 #ifndef CONFIG_ARCH_S390X
65 return *((unsigned long *) (bc+56));
67 return *((unsigned long *) (bc+112));
72 * Need to know about CPUs going idle?
74 static struct notifier_block *idle_chain;
76 int register_idle_notifier(struct notifier_block *nb)
78 return notifier_chain_register(&idle_chain, nb);
80 EXPORT_SYMBOL(register_idle_notifier);
82 int unregister_idle_notifier(struct notifier_block *nb)
84 return notifier_chain_unregister(&idle_chain, nb);
86 EXPORT_SYMBOL(unregister_idle_notifier);
88 void do_monitor_call(struct pt_regs *regs, long interruption_code)
90 /* disable monitor call class 0 */
91 __ctl_clear_bit(8, 15);
93 notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
94 (void *)(long) smp_processor_id());
98 * The idle loop on a S390...
100 void default_idle(void)
107 if (need_resched()) {
113 /* CPU is going idle. */
114 cpu = smp_processor_id();
115 rc = notifier_call_chain(&idle_chain, CPU_IDLE, (void *)(long) cpu);
116 if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
118 if (rc != NOTIFY_OK) {
123 /* enable monitor call class 0 */
124 __ctl_set_bit(8, 15);
126 #ifdef CONFIG_HOTPLUG_CPU
127 if (cpu_is_offline(smp_processor_id()))
132 * Wait for external, I/O or machine check interrupt and
133 * switch off machine check bit after the wait has ended.
135 wait_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK | PSW_MASK_WAIT |
136 PSW_MASK_IO | PSW_MASK_EXT;
137 #ifndef CONFIG_ARCH_S390X
140 "0: la %0,1f-0b(%0)\n"
144 "1: la %0,2f-1b(%0)\n"
150 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
151 #else /* CONFIG_ARCH_S390X */
161 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
162 #endif /* CONFIG_ARCH_S390X */
172 void show_regs(struct pt_regs *regs)
174 struct task_struct *tsk = current;
176 printk("CPU: %d %s\n", tsk->thread_info->cpu, print_tainted());
177 printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
178 current->comm, current->pid, (void *) tsk,
179 (void *) tsk->thread.ksp);
181 show_registers(regs);
182 /* Show stack backtrace if pt_regs is from kernel mode */
183 if (!(regs->psw.mask & PSW_MASK_PSTATE))
184 show_trace(0,(unsigned long *) regs->gprs[15]);
187 extern void kernel_thread_starter(void);
189 #ifndef CONFIG_ARCH_S390X
192 "kernel_thread_starter:\n"
201 #else /* CONFIG_ARCH_S390X */
204 "kernel_thread_starter:\n"
213 #endif /* CONFIG_ARCH_S390X */
215 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
219 memset(®s, 0, sizeof(regs));
220 regs.psw.mask = PSW_KERNEL_BITS;
221 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
222 regs.gprs[7] = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
223 regs.gprs[8] = __LC_KERNEL_STACK;
224 regs.gprs[9] = (unsigned long) fn;
225 regs.gprs[10] = (unsigned long) arg;
226 regs.gprs[11] = (unsigned long) do_exit;
229 /* Ok, create the new process.. */
230 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
231 0, ®s, 0, NULL, NULL);
235 * Free current thread data structures etc..
237 void exit_thread(void)
241 void flush_thread(void)
244 current->used_math = 0;
245 clear_tsk_thread_flag(current, TIF_USEDFPU);
248 void release_thread(struct task_struct *dead_task)
252 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
253 unsigned long unused,
254 struct task_struct * p, struct pt_regs * regs)
258 unsigned long back_chain;
262 unsigned long scratch[2];
263 unsigned long gprs[10]; /* gprs 6 -15 */
264 unsigned int fprs[4]; /* fpr 4 and 6 */
265 unsigned int empty[4];
266 struct pt_regs childregs;
269 frame = ((struct stack_frame *)
270 (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
271 p->thread.ksp = (unsigned long) frame;
272 p->set_child_tid = p->clear_child_tid = NULL;
273 /* Store access registers to kernel stack of new process. */
274 frame->childregs = *regs;
275 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
276 frame->childregs.gprs[15] = new_stackp;
277 frame->back_chain = frame->eos = 0;
279 /* new return point is ret_from_fork */
280 frame->gprs[8] = (unsigned long) ret_from_fork;
282 /* fake return stack for resume(), don't go back to schedule */
283 frame->gprs[9] = (unsigned long) frame;
285 /* Save access registers to new thread structure. */
286 save_access_regs(&p->thread.acrs[0]);
288 #ifndef CONFIG_ARCH_S390X
290 * save fprs to current->thread.fp_regs to merge them with
291 * the emulated registers and then copy the result to the child.
293 save_fp_regs(¤t->thread.fp_regs);
294 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
295 sizeof(s390_fp_regs));
296 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
297 /* Set a new TLS ? */
298 if (clone_flags & CLONE_SETTLS)
299 p->thread.acrs[0] = regs->gprs[6];
300 #else /* CONFIG_ARCH_S390X */
301 /* Save the fpu registers to new thread structure. */
302 save_fp_regs(&p->thread.fp_regs);
303 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
304 /* Set a new TLS ? */
305 if (clone_flags & CLONE_SETTLS) {
306 if (test_thread_flag(TIF_31BIT)) {
307 p->thread.acrs[0] = (unsigned int) regs->gprs[6];
309 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
310 p->thread.acrs[1] = (unsigned int) regs->gprs[6];
313 #endif /* CONFIG_ARCH_S390X */
314 /* start new process with ar4 pointing to the correct address space */
315 p->thread.mm_segment = get_fs();
316 /* Don't copy debug registers */
317 memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
322 asmlinkage long sys_fork(struct pt_regs regs)
324 return do_fork(SIGCHLD, regs.gprs[15], ®s, 0, NULL, NULL);
327 asmlinkage long sys_clone(struct pt_regs regs)
329 unsigned long clone_flags;
331 int __user *parent_tidptr, *child_tidptr;
333 clone_flags = regs.gprs[3];
334 newsp = regs.orig_gpr2;
335 parent_tidptr = (int __user *) regs.gprs[4];
336 child_tidptr = (int __user *) regs.gprs[5];
338 newsp = regs.gprs[15];
339 return do_fork(clone_flags & ~CLONE_IDLETASK, newsp, ®s, 0,
340 parent_tidptr, child_tidptr);
344 * This is trivial, and on the face of it looks like it
345 * could equally well be done in user mode.
347 * Not so, for quite unobvious reasons - register pressure.
348 * In user mode vfork() cannot have a stack frame, and if
349 * done by calling the "clone()" system call directly, you
350 * do not have enough call-clobbered registers to hold all
351 * the information you need.
353 asmlinkage long sys_vfork(struct pt_regs regs)
355 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
356 regs.gprs[15], ®s, 0, NULL, NULL);
360 * sys_execve() executes a new program.
362 asmlinkage long sys_execve(struct pt_regs regs)
367 filename = getname((char __user *) regs.orig_gpr2);
368 error = PTR_ERR(filename);
369 if (IS_ERR(filename))
371 error = do_execve(filename, (char __user * __user *) regs.gprs[3],
372 (char __user * __user *) regs.gprs[4], ®s);
374 current->ptrace &= ~PT_DTRACE;
375 current->thread.fp_regs.fpc = 0;
376 if (MACHINE_HAS_IEEE)
377 asm volatile("sfpc %0,%0" : : "d" (0));
386 * fill in the FPU structure for a core dump.
388 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
390 #ifndef CONFIG_ARCH_S390X
392 * save fprs to current->thread.fp_regs to merge them with
393 * the emulated registers and then copy the result to the dump.
395 save_fp_regs(¤t->thread.fp_regs);
396 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
397 #else /* CONFIG_ARCH_S390X */
398 save_fp_regs(fpregs);
399 #endif /* CONFIG_ARCH_S390X */
404 * fill in the user structure for a core dump..
406 void dump_thread(struct pt_regs * regs, struct user * dump)
409 /* changed the size calculations - should hopefully work better. lbt */
410 dump->magic = CMAGIC;
411 dump->start_code = 0;
412 dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
413 dump->u_tsize = current->mm->end_code >> PAGE_SHIFT;
414 dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT;
415 dump->u_dsize -= dump->u_tsize;
417 if (dump->start_stack < TASK_SIZE)
418 dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT;
419 memcpy(&dump->regs, regs, sizeof(s390_regs));
420 dump_fpu (regs, &dump->regs.fp_regs);
421 dump->regs.per_info = current->thread.per_info;
424 unsigned long get_wchan(struct task_struct *p)
426 unsigned long r14, r15, bc;
427 unsigned long stack_page;
429 if (!p || p == current || p->state == TASK_RUNNING)
431 stack_page = (unsigned long) p->thread_info;
433 if (!stack_page || r15 < stack_page ||
434 r15 >= THREAD_SIZE - sizeof(unsigned long) + stack_page)
436 bc = (*(unsigned long *) r15) & PSW_ADDR_INSN;
438 if (bc < stack_page ||
439 bc >= THREAD_SIZE - sizeof(unsigned long) + stack_page)
441 #ifndef CONFIG_ARCH_S390X
442 r14 = (*(unsigned long *) (bc+56)) & PSW_ADDR_INSN;
444 r14 = *(unsigned long *) (bc+112);
446 if (!in_sched_functions(r14))
448 bc = (*(unsigned long *) bc) & PSW_ADDR_INSN;
449 } while (count++ < 16);