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/stddef.h>
26 #include <linux/unistd.h>
27 #include <linux/ptrace.h>
28 #include <linux/slab.h>
29 #include <linux/vmalloc.h>
30 #include <linux/user.h>
31 #include <linux/a.out.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>
39 #include <asm/uaccess.h>
40 #include <asm/pgtable.h>
41 #include <asm/system.h>
43 #include <asm/processor.h>
45 #include <asm/timer.h>
47 asmlinkage
void ret_from_fork(void) asm ("ret_from_fork");
50 * Return saved PC of a blocked thread. used in kernel/sched.
51 * resume in entry.S does not create a new stack frame, it
52 * just stores the registers %r6-%r15 to the frame given by
53 * schedule. We want to return the address of the caller of
54 * schedule, so we have to walk the backchain one time to
55 * find the frame schedule() store its return address.
57 unsigned long thread_saved_pc(struct task_struct
*tsk
)
59 struct stack_frame
*sf
, *low
, *high
;
61 if (!tsk
|| !task_stack_page(tsk
))
63 low
= task_stack_page(tsk
);
64 high
= (struct stack_frame
*) task_pt_regs(tsk
);
65 sf
= (struct stack_frame
*) (tsk
->thread
.ksp
& PSW_ADDR_INSN
);
66 if (sf
<= low
|| sf
> high
)
68 sf
= (struct stack_frame
*) (sf
->back_chain
& PSW_ADDR_INSN
);
69 if (sf
<= low
|| sf
> high
)
75 * Need to know about CPUs going idle?
77 static ATOMIC_NOTIFIER_HEAD(idle_chain
);
79 int register_idle_notifier(struct notifier_block
*nb
)
81 return atomic_notifier_chain_register(&idle_chain
, nb
);
83 EXPORT_SYMBOL(register_idle_notifier
);
85 int unregister_idle_notifier(struct notifier_block
*nb
)
87 return atomic_notifier_chain_unregister(&idle_chain
, nb
);
89 EXPORT_SYMBOL(unregister_idle_notifier
);
91 void do_monitor_call(struct pt_regs
*regs
, long interruption_code
)
93 /* disable monitor call class 0 */
94 __ctl_clear_bit(8, 15);
96 atomic_notifier_call_chain(&idle_chain
, CPU_NOT_IDLE
,
97 (void *)(long) smp_processor_id());
100 extern void s390_handle_mcck(void);
102 * The idle loop on a S390...
104 static void default_idle(void)
108 /* CPU is going idle. */
109 cpu
= smp_processor_id();
112 if (need_resched()) {
117 rc
= atomic_notifier_call_chain(&idle_chain
,
118 CPU_IDLE
, (void *)(long) cpu
);
119 if (rc
!= NOTIFY_OK
&& rc
!= NOTIFY_DONE
)
121 if (rc
!= NOTIFY_OK
) {
126 /* enable monitor call class 0 */
127 __ctl_set_bit(8, 15);
129 #ifdef CONFIG_HOTPLUG_CPU
130 if (cpu_is_offline(cpu
)) {
131 preempt_enable_no_resched();
136 local_mcck_disable();
137 if (test_thread_flag(TIF_MCCK_PENDING
)) {
145 /* Wait for external, I/O or machine check interrupt. */
146 __load_psw_mask(psw_kernel_bits
| PSW_MASK_WAIT
|
147 PSW_MASK_IO
| PSW_MASK_EXT
);
153 while (!need_resched())
156 preempt_enable_no_resched();
162 void show_regs(struct pt_regs
*regs
)
164 struct task_struct
*tsk
= current
;
166 printk("CPU: %d %s\n", task_thread_info(tsk
)->cpu
, print_tainted());
167 printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
168 current
->comm
, current
->pid
, (void *) tsk
,
169 (void *) tsk
->thread
.ksp
);
171 show_registers(regs
);
172 /* Show stack backtrace if pt_regs is from kernel mode */
173 if (!(regs
->psw
.mask
& PSW_MASK_PSTATE
))
174 show_trace(NULL
, (unsigned long *) regs
->gprs
[15]);
177 extern void kernel_thread_starter(void);
181 "kernel_thread_starter:\n"
187 int kernel_thread(int (*fn
)(void *), void * arg
, unsigned long flags
)
191 memset(®s
, 0, sizeof(regs
));
192 regs
.psw
.mask
= psw_kernel_bits
| PSW_MASK_IO
| PSW_MASK_EXT
;
193 regs
.psw
.addr
= (unsigned long) kernel_thread_starter
| PSW_ADDR_AMODE
;
194 regs
.gprs
[9] = (unsigned long) fn
;
195 regs
.gprs
[10] = (unsigned long) arg
;
196 regs
.gprs
[11] = (unsigned long) do_exit
;
199 /* Ok, create the new process.. */
200 return do_fork(flags
| CLONE_VM
| CLONE_UNTRACED
,
201 0, ®s
, 0, NULL
, NULL
);
205 * Free current thread data structures etc..
207 void exit_thread(void)
211 void flush_thread(void)
214 clear_tsk_thread_flag(current
, TIF_USEDFPU
);
217 void release_thread(struct task_struct
*dead_task
)
221 int copy_thread(int nr
, unsigned long clone_flags
, unsigned long new_stackp
,
222 unsigned long unused
,
223 struct task_struct
* p
, struct pt_regs
* regs
)
227 struct stack_frame sf
;
228 struct pt_regs childregs
;
231 frame
= container_of(task_pt_regs(p
), struct fake_frame
, childregs
);
232 p
->thread
.ksp
= (unsigned long) frame
;
233 /* Store access registers to kernel stack of new process. */
234 frame
->childregs
= *regs
;
235 frame
->childregs
.gprs
[2] = 0; /* child returns 0 on fork. */
236 frame
->childregs
.gprs
[15] = new_stackp
;
237 frame
->sf
.back_chain
= 0;
239 /* new return point is ret_from_fork */
240 frame
->sf
.gprs
[8] = (unsigned long) ret_from_fork
;
242 /* fake return stack for resume(), don't go back to schedule */
243 frame
->sf
.gprs
[9] = (unsigned long) frame
;
245 /* Save access registers to new thread structure. */
246 save_access_regs(&p
->thread
.acrs
[0]);
250 * save fprs to current->thread.fp_regs to merge them with
251 * the emulated registers and then copy the result to the child.
253 save_fp_regs(¤t
->thread
.fp_regs
);
254 memcpy(&p
->thread
.fp_regs
, ¤t
->thread
.fp_regs
,
255 sizeof(s390_fp_regs
));
256 p
->thread
.user_seg
= __pa((unsigned long) p
->mm
->pgd
) | _SEGMENT_TABLE
;
257 /* Set a new TLS ? */
258 if (clone_flags
& CLONE_SETTLS
)
259 p
->thread
.acrs
[0] = regs
->gprs
[6];
260 #else /* CONFIG_64BIT */
261 /* Save the fpu registers to new thread structure. */
262 save_fp_regs(&p
->thread
.fp_regs
);
263 p
->thread
.user_seg
= __pa((unsigned long) p
->mm
->pgd
) | _REGION_TABLE
;
264 /* Set a new TLS ? */
265 if (clone_flags
& CLONE_SETTLS
) {
266 if (test_thread_flag(TIF_31BIT
)) {
267 p
->thread
.acrs
[0] = (unsigned int) regs
->gprs
[6];
269 p
->thread
.acrs
[0] = (unsigned int)(regs
->gprs
[6] >> 32);
270 p
->thread
.acrs
[1] = (unsigned int) regs
->gprs
[6];
273 #endif /* CONFIG_64BIT */
274 /* start new process with ar4 pointing to the correct address space */
275 p
->thread
.mm_segment
= get_fs();
276 /* Don't copy debug registers */
277 memset(&p
->thread
.per_info
,0,sizeof(p
->thread
.per_info
));
282 asmlinkage
long sys_fork(void)
284 struct pt_regs
*regs
= task_pt_regs(current
);
285 return do_fork(SIGCHLD
, regs
->gprs
[15], regs
, 0, NULL
, NULL
);
288 asmlinkage
long sys_clone(void)
290 struct pt_regs
*regs
= task_pt_regs(current
);
291 unsigned long clone_flags
;
293 int __user
*parent_tidptr
, *child_tidptr
;
295 clone_flags
= regs
->gprs
[3];
296 newsp
= regs
->orig_gpr2
;
297 parent_tidptr
= (int __user
*) regs
->gprs
[4];
298 child_tidptr
= (int __user
*) regs
->gprs
[5];
300 newsp
= regs
->gprs
[15];
301 return do_fork(clone_flags
, newsp
, regs
, 0,
302 parent_tidptr
, child_tidptr
);
306 * This is trivial, and on the face of it looks like it
307 * could equally well be done in user mode.
309 * Not so, for quite unobvious reasons - register pressure.
310 * In user mode vfork() cannot have a stack frame, and if
311 * done by calling the "clone()" system call directly, you
312 * do not have enough call-clobbered registers to hold all
313 * the information you need.
315 asmlinkage
long sys_vfork(void)
317 struct pt_regs
*regs
= task_pt_regs(current
);
318 return do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
,
319 regs
->gprs
[15], regs
, 0, NULL
, NULL
);
322 asmlinkage
void execve_tail(void)
325 current
->ptrace
&= ~PT_DTRACE
;
326 task_unlock(current
);
327 current
->thread
.fp_regs
.fpc
= 0;
328 if (MACHINE_HAS_IEEE
)
329 asm volatile("sfpc %0,%0" : : "d" (0));
333 * sys_execve() executes a new program.
335 asmlinkage
long sys_execve(void)
337 struct pt_regs
*regs
= task_pt_regs(current
);
339 unsigned long result
;
342 filename
= getname((char __user
*) regs
->orig_gpr2
);
343 if (IS_ERR(filename
)) {
344 result
= PTR_ERR(filename
);
347 rc
= do_execve(filename
, (char __user
* __user
*) regs
->gprs
[3],
348 (char __user
* __user
*) regs
->gprs
[4], regs
);
354 result
= regs
->gprs
[2];
362 * fill in the FPU structure for a core dump.
364 int dump_fpu (struct pt_regs
* regs
, s390_fp_regs
*fpregs
)
368 * save fprs to current->thread.fp_regs to merge them with
369 * the emulated registers and then copy the result to the dump.
371 save_fp_regs(¤t
->thread
.fp_regs
);
372 memcpy(fpregs
, ¤t
->thread
.fp_regs
, sizeof(s390_fp_regs
));
373 #else /* CONFIG_64BIT */
374 save_fp_regs(fpregs
);
375 #endif /* CONFIG_64BIT */
379 unsigned long get_wchan(struct task_struct
*p
)
381 struct stack_frame
*sf
, *low
, *high
;
382 unsigned long return_address
;
385 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
|| !task_stack_page(p
))
387 low
= task_stack_page(p
);
388 high
= (struct stack_frame
*) task_pt_regs(p
);
389 sf
= (struct stack_frame
*) (p
->thread
.ksp
& PSW_ADDR_INSN
);
390 if (sf
<= low
|| sf
> high
)
392 for (count
= 0; count
< 16; count
++) {
393 sf
= (struct stack_frame
*) (sf
->back_chain
& PSW_ADDR_INSN
);
394 if (sf
<= low
|| sf
> high
)
396 return_address
= sf
->gprs
[8] & PSW_ADDR_INSN
;
397 if (!in_sched_functions(return_address
))
398 return return_address
;