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 <linux/kernel_stat.h>
42 #include <asm/uaccess.h>
43 #include <asm/pgtable.h>
44 #include <asm/system.h>
46 #include <asm/processor.h>
48 #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 extern void s390_handle_mcck(void);
80 * The idle loop on a S390...
82 static void default_idle(void)
84 /* CPU is going idle. */
90 #ifdef CONFIG_HOTPLUG_CPU
91 if (cpu_is_offline(smp_processor_id())) {
92 preempt_enable_no_resched();
97 if (test_thread_flag(TIF_MCCK_PENDING
)) {
104 /* Don't trace preempt off for idle. */
105 stop_critical_timings();
106 /* Stop virtual timer and halt the cpu. */
108 /* Reenable preemption tracer. */
109 start_critical_timings();
115 tick_nohz_stop_sched_tick(1);
116 while (!need_resched())
118 tick_nohz_restart_sched_tick();
119 preempt_enable_no_resched();
125 extern void kernel_thread_starter(void);
129 "kernel_thread_starter:\n"
135 int kernel_thread(int (*fn
)(void *), void * arg
, unsigned long flags
)
139 memset(®s
, 0, sizeof(regs
));
140 regs
.psw
.mask
= psw_kernel_bits
| PSW_MASK_IO
| PSW_MASK_EXT
;
141 regs
.psw
.addr
= (unsigned long) kernel_thread_starter
| PSW_ADDR_AMODE
;
142 regs
.gprs
[9] = (unsigned long) fn
;
143 regs
.gprs
[10] = (unsigned long) arg
;
144 regs
.gprs
[11] = (unsigned long) do_exit
;
147 /* Ok, create the new process.. */
148 return do_fork(flags
| CLONE_VM
| CLONE_UNTRACED
,
149 0, ®s
, 0, NULL
, NULL
);
153 * Free current thread data structures etc..
155 void exit_thread(void)
159 void flush_thread(void)
162 clear_tsk_thread_flag(current
, TIF_USEDFPU
);
165 void release_thread(struct task_struct
*dead_task
)
169 int copy_thread(int nr
, unsigned long clone_flags
, unsigned long new_stackp
,
170 unsigned long unused
,
171 struct task_struct
* p
, struct pt_regs
* regs
)
175 struct stack_frame sf
;
176 struct pt_regs childregs
;
179 frame
= container_of(task_pt_regs(p
), struct fake_frame
, childregs
);
180 p
->thread
.ksp
= (unsigned long) frame
;
181 /* Store access registers to kernel stack of new process. */
182 frame
->childregs
= *regs
;
183 frame
->childregs
.gprs
[2] = 0; /* child returns 0 on fork. */
184 frame
->childregs
.gprs
[15] = new_stackp
;
185 frame
->sf
.back_chain
= 0;
187 /* new return point is ret_from_fork */
188 frame
->sf
.gprs
[8] = (unsigned long) ret_from_fork
;
190 /* fake return stack for resume(), don't go back to schedule */
191 frame
->sf
.gprs
[9] = (unsigned long) frame
;
193 /* Save access registers to new thread structure. */
194 save_access_regs(&p
->thread
.acrs
[0]);
198 * save fprs to current->thread.fp_regs to merge them with
199 * the emulated registers and then copy the result to the child.
201 save_fp_regs(¤t
->thread
.fp_regs
);
202 memcpy(&p
->thread
.fp_regs
, ¤t
->thread
.fp_regs
,
203 sizeof(s390_fp_regs
));
204 /* Set a new TLS ? */
205 if (clone_flags
& CLONE_SETTLS
)
206 p
->thread
.acrs
[0] = regs
->gprs
[6];
207 #else /* CONFIG_64BIT */
208 /* Save the fpu registers to new thread structure. */
209 save_fp_regs(&p
->thread
.fp_regs
);
210 /* Set a new TLS ? */
211 if (clone_flags
& CLONE_SETTLS
) {
212 if (test_thread_flag(TIF_31BIT
)) {
213 p
->thread
.acrs
[0] = (unsigned int) regs
->gprs
[6];
215 p
->thread
.acrs
[0] = (unsigned int)(regs
->gprs
[6] >> 32);
216 p
->thread
.acrs
[1] = (unsigned int) regs
->gprs
[6];
219 #endif /* CONFIG_64BIT */
220 /* start new process with ar4 pointing to the correct address space */
221 p
->thread
.mm_segment
= get_fs();
222 /* Don't copy debug registers */
223 memset(&p
->thread
.per_info
,0,sizeof(p
->thread
.per_info
));
228 asmlinkage
long sys_fork(void)
230 struct pt_regs
*regs
= task_pt_regs(current
);
231 return do_fork(SIGCHLD
, regs
->gprs
[15], regs
, 0, NULL
, NULL
);
234 asmlinkage
long sys_clone(void)
236 struct pt_regs
*regs
= task_pt_regs(current
);
237 unsigned long clone_flags
;
239 int __user
*parent_tidptr
, *child_tidptr
;
241 clone_flags
= regs
->gprs
[3];
242 newsp
= regs
->orig_gpr2
;
243 parent_tidptr
= (int __user
*) regs
->gprs
[4];
244 child_tidptr
= (int __user
*) regs
->gprs
[5];
246 newsp
= regs
->gprs
[15];
247 return do_fork(clone_flags
, newsp
, regs
, 0,
248 parent_tidptr
, child_tidptr
);
252 * This is trivial, and on the face of it looks like it
253 * could equally well be done in user mode.
255 * Not so, for quite unobvious reasons - register pressure.
256 * In user mode vfork() cannot have a stack frame, and if
257 * done by calling the "clone()" system call directly, you
258 * do not have enough call-clobbered registers to hold all
259 * the information you need.
261 asmlinkage
long sys_vfork(void)
263 struct pt_regs
*regs
= task_pt_regs(current
);
264 return do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
,
265 regs
->gprs
[15], regs
, 0, NULL
, NULL
);
268 asmlinkage
void execve_tail(void)
271 current
->ptrace
&= ~PT_DTRACE
;
272 task_unlock(current
);
273 current
->thread
.fp_regs
.fpc
= 0;
274 if (MACHINE_HAS_IEEE
)
275 asm volatile("sfpc %0,%0" : : "d" (0));
279 * sys_execve() executes a new program.
281 asmlinkage
long sys_execve(void)
283 struct pt_regs
*regs
= task_pt_regs(current
);
285 unsigned long result
;
288 filename
= getname((char __user
*) regs
->orig_gpr2
);
289 if (IS_ERR(filename
)) {
290 result
= PTR_ERR(filename
);
293 rc
= do_execve(filename
, (char __user
* __user
*) regs
->gprs
[3],
294 (char __user
* __user
*) regs
->gprs
[4], regs
);
300 result
= regs
->gprs
[2];
308 * fill in the FPU structure for a core dump.
310 int dump_fpu (struct pt_regs
* regs
, s390_fp_regs
*fpregs
)
314 * save fprs to current->thread.fp_regs to merge them with
315 * the emulated registers and then copy the result to the dump.
317 save_fp_regs(¤t
->thread
.fp_regs
);
318 memcpy(fpregs
, ¤t
->thread
.fp_regs
, sizeof(s390_fp_regs
));
319 #else /* CONFIG_64BIT */
320 save_fp_regs(fpregs
);
321 #endif /* CONFIG_64BIT */
325 unsigned long get_wchan(struct task_struct
*p
)
327 struct stack_frame
*sf
, *low
, *high
;
328 unsigned long return_address
;
331 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
|| !task_stack_page(p
))
333 low
= task_stack_page(p
);
334 high
= (struct stack_frame
*) task_pt_regs(p
);
335 sf
= (struct stack_frame
*) (p
->thread
.ksp
& PSW_ADDR_INSN
);
336 if (sf
<= low
|| sf
> high
)
338 for (count
= 0; count
< 16; count
++) {
339 sf
= (struct stack_frame
*) (sf
->back_chain
& PSW_ADDR_INSN
);
340 if (sf
<= low
|| sf
> high
)
342 return_address
= sf
->gprs
[8] & PSW_ADDR_INSN
;
343 if (!in_sched_functions(return_address
))
344 return return_address
;