2 * This file handles the architecture dependent parts of process handling.
4 * Copyright IBM Corp. 1999,2009
5 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
6 * Hartmut Penner <hp@de.ibm.com>,
10 #include <linux/compiler.h>
11 #include <linux/cpu.h>
12 #include <linux/errno.h>
13 #include <linux/sched.h>
14 #include <linux/kernel.h>
17 #include <linux/smp.h>
18 #include <linux/stddef.h>
19 #include <linux/unistd.h>
20 #include <linux/ptrace.h>
21 #include <linux/slab.h>
22 #include <linux/vmalloc.h>
23 #include <linux/user.h>
24 #include <linux/interrupt.h>
25 #include <linux/delay.h>
26 #include <linux/reboot.h>
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/notifier.h>
30 #include <linux/utsname.h>
31 #include <linux/tick.h>
32 #include <linux/elfcore.h>
33 #include <linux/kernel_stat.h>
34 #include <linux/syscalls.h>
35 #include <asm/uaccess.h>
36 #include <asm/pgtable.h>
37 #include <asm/system.h>
39 #include <asm/processor.h>
41 #include <asm/timer.h>
45 asmlinkage
void ret_from_fork(void) asm ("ret_from_fork");
48 * Return saved PC of a blocked thread. used in kernel/sched.
49 * resume in entry.S does not create a new stack frame, it
50 * just stores the registers %r6-%r15 to the frame given by
51 * schedule. We want to return the address of the caller of
52 * schedule, so we have to walk the backchain one time to
53 * find the frame schedule() store its return address.
55 unsigned long thread_saved_pc(struct task_struct
*tsk
)
57 struct stack_frame
*sf
, *low
, *high
;
59 if (!tsk
|| !task_stack_page(tsk
))
61 low
= task_stack_page(tsk
);
62 high
= (struct stack_frame
*) task_pt_regs(tsk
);
63 sf
= (struct stack_frame
*) (tsk
->thread
.ksp
& PSW_ADDR_INSN
);
64 if (sf
<= low
|| sf
> high
)
66 sf
= (struct stack_frame
*) (sf
->back_chain
& PSW_ADDR_INSN
);
67 if (sf
<= low
|| sf
> high
)
73 * The idle loop on a S390...
75 static void default_idle(void)
77 /* CPU is going idle. */
83 #ifdef CONFIG_HOTPLUG_CPU
84 if (cpu_is_offline(smp_processor_id())) {
85 preempt_enable_no_resched();
90 if (test_thread_flag(TIF_MCCK_PENDING
)) {
97 /* Don't trace preempt off for idle. */
98 stop_critical_timings();
99 /* Stop virtual timer and halt the cpu. */
101 /* Reenable preemption tracer. */
102 start_critical_timings();
108 tick_nohz_stop_sched_tick(1);
109 while (!need_resched())
111 tick_nohz_restart_sched_tick();
112 preempt_enable_no_resched();
118 extern void kernel_thread_starter(void);
122 "kernel_thread_starter:\n"
128 int kernel_thread(int (*fn
)(void *), void * arg
, unsigned long flags
)
132 memset(®s
, 0, sizeof(regs
));
133 regs
.psw
.mask
= psw_kernel_bits
| PSW_MASK_IO
| PSW_MASK_EXT
;
134 regs
.psw
.addr
= (unsigned long) kernel_thread_starter
| PSW_ADDR_AMODE
;
135 regs
.gprs
[9] = (unsigned long) fn
;
136 regs
.gprs
[10] = (unsigned long) arg
;
137 regs
.gprs
[11] = (unsigned long) do_exit
;
140 /* Ok, create the new process.. */
141 return do_fork(flags
| CLONE_VM
| CLONE_UNTRACED
,
142 0, ®s
, 0, NULL
, NULL
);
146 * Free current thread data structures etc..
148 void exit_thread(void)
152 void flush_thread(void)
155 clear_tsk_thread_flag(current
, TIF_USEDFPU
);
158 void release_thread(struct task_struct
*dead_task
)
162 int copy_thread(int nr
, unsigned long clone_flags
, unsigned long new_stackp
,
163 unsigned long unused
,
164 struct task_struct
*p
, struct pt_regs
*regs
)
166 struct thread_info
*ti
;
169 struct stack_frame sf
;
170 struct pt_regs childregs
;
173 frame
= container_of(task_pt_regs(p
), struct fake_frame
, childregs
);
174 p
->thread
.ksp
= (unsigned long) frame
;
175 /* Store access registers to kernel stack of new process. */
176 frame
->childregs
= *regs
;
177 frame
->childregs
.gprs
[2] = 0; /* child returns 0 on fork. */
178 frame
->childregs
.gprs
[15] = new_stackp
;
179 frame
->sf
.back_chain
= 0;
181 /* new return point is ret_from_fork */
182 frame
->sf
.gprs
[8] = (unsigned long) ret_from_fork
;
184 /* fake return stack for resume(), don't go back to schedule */
185 frame
->sf
.gprs
[9] = (unsigned long) frame
;
187 /* Save access registers to new thread structure. */
188 save_access_regs(&p
->thread
.acrs
[0]);
192 * save fprs to current->thread.fp_regs to merge them with
193 * the emulated registers and then copy the result to the child.
195 save_fp_regs(¤t
->thread
.fp_regs
);
196 memcpy(&p
->thread
.fp_regs
, ¤t
->thread
.fp_regs
,
197 sizeof(s390_fp_regs
));
198 /* Set a new TLS ? */
199 if (clone_flags
& CLONE_SETTLS
)
200 p
->thread
.acrs
[0] = regs
->gprs
[6];
201 #else /* CONFIG_64BIT */
202 /* Save the fpu registers to new thread structure. */
203 save_fp_regs(&p
->thread
.fp_regs
);
204 /* Set a new TLS ? */
205 if (clone_flags
& CLONE_SETTLS
) {
206 if (test_thread_flag(TIF_31BIT
)) {
207 p
->thread
.acrs
[0] = (unsigned int) regs
->gprs
[6];
209 p
->thread
.acrs
[0] = (unsigned int)(regs
->gprs
[6] >> 32);
210 p
->thread
.acrs
[1] = (unsigned int) regs
->gprs
[6];
213 #endif /* CONFIG_64BIT */
214 /* start new process with ar4 pointing to the correct address space */
215 p
->thread
.mm_segment
= get_fs();
216 /* Don't copy debug registers */
217 memset(&p
->thread
.per_info
, 0, sizeof(p
->thread
.per_info
));
218 /* Initialize per thread user and system timer values */
219 ti
= task_thread_info(p
);
221 ti
->system_timer
= 0;
225 SYSCALL_DEFINE0(fork
)
227 struct pt_regs
*regs
= task_pt_regs(current
);
228 return do_fork(SIGCHLD
, regs
->gprs
[15], regs
, 0, NULL
, NULL
);
231 SYSCALL_DEFINE0(clone
)
233 struct pt_regs
*regs
= task_pt_regs(current
);
234 unsigned long clone_flags
;
236 int __user
*parent_tidptr
, *child_tidptr
;
238 clone_flags
= regs
->gprs
[3];
239 newsp
= regs
->orig_gpr2
;
240 parent_tidptr
= (int __user
*) regs
->gprs
[4];
241 child_tidptr
= (int __user
*) regs
->gprs
[5];
243 newsp
= regs
->gprs
[15];
244 return do_fork(clone_flags
, newsp
, regs
, 0,
245 parent_tidptr
, child_tidptr
);
249 * This is trivial, and on the face of it looks like it
250 * could equally well be done in user mode.
252 * Not so, for quite unobvious reasons - register pressure.
253 * In user mode vfork() cannot have a stack frame, and if
254 * done by calling the "clone()" system call directly, you
255 * do not have enough call-clobbered registers to hold all
256 * the information you need.
258 SYSCALL_DEFINE0(vfork
)
260 struct pt_regs
*regs
= task_pt_regs(current
);
261 return do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
,
262 regs
->gprs
[15], regs
, 0, NULL
, NULL
);
265 asmlinkage
void execve_tail(void)
268 current
->ptrace
&= ~PT_DTRACE
;
269 task_unlock(current
);
270 current
->thread
.fp_regs
.fpc
= 0;
271 if (MACHINE_HAS_IEEE
)
272 asm volatile("sfpc %0,%0" : : "d" (0));
276 * sys_execve() executes a new program.
278 SYSCALL_DEFINE0(execve
)
280 struct pt_regs
*regs
= task_pt_regs(current
);
282 unsigned long result
;
285 filename
= getname((char __user
*) regs
->orig_gpr2
);
286 if (IS_ERR(filename
)) {
287 result
= PTR_ERR(filename
);
290 rc
= do_execve(filename
, (char __user
* __user
*) regs
->gprs
[3],
291 (char __user
* __user
*) regs
->gprs
[4], regs
);
297 result
= regs
->gprs
[2];
305 * fill in the FPU structure for a core dump.
307 int dump_fpu (struct pt_regs
* regs
, s390_fp_regs
*fpregs
)
311 * save fprs to current->thread.fp_regs to merge them with
312 * the emulated registers and then copy the result to the dump.
314 save_fp_regs(¤t
->thread
.fp_regs
);
315 memcpy(fpregs
, ¤t
->thread
.fp_regs
, sizeof(s390_fp_regs
));
316 #else /* CONFIG_64BIT */
317 save_fp_regs(fpregs
);
318 #endif /* CONFIG_64BIT */
322 unsigned long get_wchan(struct task_struct
*p
)
324 struct stack_frame
*sf
, *low
, *high
;
325 unsigned long return_address
;
328 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
|| !task_stack_page(p
))
330 low
= task_stack_page(p
);
331 high
= (struct stack_frame
*) task_pt_regs(p
);
332 sf
= (struct stack_frame
*) (p
->thread
.ksp
& PSW_ADDR_INSN
);
333 if (sf
<= low
|| sf
> high
)
335 for (count
= 0; count
< 16; count
++) {
336 sf
= (struct stack_frame
*) (sf
->back_chain
& PSW_ADDR_INSN
);
337 if (sf
<= low
|| sf
> high
)
339 return_address
= sf
->gprs
[8] & PSW_ADDR_INSN
;
340 if (!in_sched_functions(return_address
))
341 return return_address
;
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