]>
git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - arch/s390/kernel/process.c
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/sched.h>
13 #include <linux/kernel.h>
15 #include <linux/elfcore.h>
16 #include <linux/smp.h>
17 #include <linux/slab.h>
18 #include <linux/interrupt.h>
19 #include <linux/tick.h>
20 #include <linux/personality.h>
21 #include <linux/syscalls.h>
22 #include <linux/compat.h>
23 #include <linux/kprobes.h>
24 #include <linux/random.h>
25 #include <linux/module.h>
26 #include <asm/system.h>
28 #include <asm/processor.h>
30 #include <asm/timer.h>
32 #include <asm/compat.h>
36 asmlinkage
void ret_from_fork(void) asm ("ret_from_fork");
39 * Return saved PC of a blocked thread. used in kernel/sched.
40 * resume in entry.S does not create a new stack frame, it
41 * just stores the registers %r6-%r15 to the frame given by
42 * schedule. We want to return the address of the caller of
43 * schedule, so we have to walk the backchain one time to
44 * find the frame schedule() store its return address.
46 unsigned long thread_saved_pc(struct task_struct
*tsk
)
48 struct stack_frame
*sf
, *low
, *high
;
50 if (!tsk
|| !task_stack_page(tsk
))
52 low
= task_stack_page(tsk
);
53 high
= (struct stack_frame
*) task_pt_regs(tsk
);
54 sf
= (struct stack_frame
*) (tsk
->thread
.ksp
& PSW_ADDR_INSN
);
55 if (sf
<= low
|| sf
> high
)
57 sf
= (struct stack_frame
*) (sf
->back_chain
& PSW_ADDR_INSN
);
58 if (sf
<= low
|| sf
> high
)
64 * The idle loop on a S390...
66 static void default_idle(void)
68 if (cpu_is_offline(smp_processor_id()))
76 if (test_thread_flag(TIF_MCCK_PENDING
)) {
82 /* Don't trace preempt off for idle. */
83 stop_critical_timings();
84 /* Stop virtual timer and halt the cpu. */
86 /* Reenable preemption tracer. */
87 start_critical_timings();
93 tick_nohz_idle_enter();
95 while (!need_resched() && !test_thread_flag(TIF_MCCK_PENDING
))
98 tick_nohz_idle_exit();
99 if (test_thread_flag(TIF_MCCK_PENDING
))
101 preempt_enable_no_resched();
107 extern void __kprobes
kernel_thread_starter(void);
110 ".section .kprobes.text, \"ax\"\n"
111 ".global kernel_thread_starter\n"
112 "kernel_thread_starter:\n"
119 int kernel_thread(int (*fn
)(void *), void * arg
, unsigned long flags
)
123 memset(®s
, 0, sizeof(regs
));
124 regs
.psw
.mask
= psw_kernel_bits
|
125 PSW_MASK_DAT
| PSW_MASK_IO
| PSW_MASK_EXT
| PSW_MASK_MCHECK
;
126 regs
.psw
.addr
= (unsigned long) kernel_thread_starter
| PSW_ADDR_AMODE
;
127 regs
.gprs
[9] = (unsigned long) fn
;
128 regs
.gprs
[10] = (unsigned long) arg
;
129 regs
.gprs
[11] = (unsigned long) do_exit
;
132 /* Ok, create the new process.. */
133 return do_fork(flags
| CLONE_VM
| CLONE_UNTRACED
,
134 0, ®s
, 0, NULL
, NULL
);
136 EXPORT_SYMBOL(kernel_thread
);
139 * Free current thread data structures etc..
141 void exit_thread(void)
145 void flush_thread(void)
149 void release_thread(struct task_struct
*dead_task
)
153 int copy_thread(unsigned long clone_flags
, unsigned long new_stackp
,
154 unsigned long unused
,
155 struct task_struct
*p
, struct pt_regs
*regs
)
157 struct thread_info
*ti
;
160 struct stack_frame sf
;
161 struct pt_regs childregs
;
164 frame
= container_of(task_pt_regs(p
), struct fake_frame
, childregs
);
165 p
->thread
.ksp
= (unsigned long) frame
;
166 /* Store access registers to kernel stack of new process. */
167 frame
->childregs
= *regs
;
168 frame
->childregs
.gprs
[2] = 0; /* child returns 0 on fork. */
169 frame
->childregs
.gprs
[15] = new_stackp
;
170 frame
->sf
.back_chain
= 0;
172 /* new return point is ret_from_fork */
173 frame
->sf
.gprs
[8] = (unsigned long) ret_from_fork
;
175 /* fake return stack for resume(), don't go back to schedule */
176 frame
->sf
.gprs
[9] = (unsigned long) frame
;
178 /* Save access registers to new thread structure. */
179 save_access_regs(&p
->thread
.acrs
[0]);
183 * save fprs to current->thread.fp_regs to merge them with
184 * the emulated registers and then copy the result to the child.
186 save_fp_regs(¤t
->thread
.fp_regs
);
187 memcpy(&p
->thread
.fp_regs
, ¤t
->thread
.fp_regs
,
188 sizeof(s390_fp_regs
));
189 /* Set a new TLS ? */
190 if (clone_flags
& CLONE_SETTLS
)
191 p
->thread
.acrs
[0] = regs
->gprs
[6];
192 #else /* CONFIG_64BIT */
193 /* Save the fpu registers to new thread structure. */
194 save_fp_regs(&p
->thread
.fp_regs
);
195 /* Set a new TLS ? */
196 if (clone_flags
& CLONE_SETTLS
) {
197 if (is_compat_task()) {
198 p
->thread
.acrs
[0] = (unsigned int) regs
->gprs
[6];
200 p
->thread
.acrs
[0] = (unsigned int)(regs
->gprs
[6] >> 32);
201 p
->thread
.acrs
[1] = (unsigned int) regs
->gprs
[6];
204 #endif /* CONFIG_64BIT */
205 /* start new process with ar4 pointing to the correct address space */
206 p
->thread
.mm_segment
= get_fs();
207 /* Don't copy debug registers */
208 memset(&p
->thread
.per_user
, 0, sizeof(p
->thread
.per_user
));
209 memset(&p
->thread
.per_event
, 0, sizeof(p
->thread
.per_event
));
210 clear_tsk_thread_flag(p
, TIF_SINGLE_STEP
);
211 clear_tsk_thread_flag(p
, TIF_PER_TRAP
);
212 /* Initialize per thread user and system timer values */
213 ti
= task_thread_info(p
);
215 ti
->system_timer
= 0;
219 SYSCALL_DEFINE0(fork
)
221 struct pt_regs
*regs
= task_pt_regs(current
);
222 return do_fork(SIGCHLD
, regs
->gprs
[15], regs
, 0, NULL
, NULL
);
225 SYSCALL_DEFINE4(clone
, unsigned long, newsp
, unsigned long, clone_flags
,
226 int __user
*, parent_tidptr
, int __user
*, child_tidptr
)
228 struct pt_regs
*regs
= task_pt_regs(current
);
231 newsp
= regs
->gprs
[15];
232 return do_fork(clone_flags
, newsp
, regs
, 0,
233 parent_tidptr
, child_tidptr
);
237 * This is trivial, and on the face of it looks like it
238 * could equally well be done in user mode.
240 * Not so, for quite unobvious reasons - register pressure.
241 * In user mode vfork() cannot have a stack frame, and if
242 * done by calling the "clone()" system call directly, you
243 * do not have enough call-clobbered registers to hold all
244 * the information you need.
246 SYSCALL_DEFINE0(vfork
)
248 struct pt_regs
*regs
= task_pt_regs(current
);
249 return do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
,
250 regs
->gprs
[15], regs
, 0, NULL
, NULL
);
253 asmlinkage
void execve_tail(void)
255 current
->thread
.fp_regs
.fpc
= 0;
256 if (MACHINE_HAS_IEEE
)
257 asm volatile("sfpc %0,%0" : : "d" (0));
261 * sys_execve() executes a new program.
263 SYSCALL_DEFINE3(execve
, const char __user
*, name
,
264 const char __user
*const __user
*, argv
,
265 const char __user
*const __user
*, envp
)
267 struct pt_regs
*regs
= task_pt_regs(current
);
271 filename
= getname(name
);
272 rc
= PTR_ERR(filename
);
273 if (IS_ERR(filename
))
275 rc
= do_execve(filename
, argv
, envp
, regs
);
286 * fill in the FPU structure for a core dump.
288 int dump_fpu (struct pt_regs
* regs
, s390_fp_regs
*fpregs
)
292 * save fprs to current->thread.fp_regs to merge them with
293 * the emulated registers and then copy the result to the dump.
295 save_fp_regs(¤t
->thread
.fp_regs
);
296 memcpy(fpregs
, ¤t
->thread
.fp_regs
, sizeof(s390_fp_regs
));
297 #else /* CONFIG_64BIT */
298 save_fp_regs(fpregs
);
299 #endif /* CONFIG_64BIT */
302 EXPORT_SYMBOL(dump_fpu
);
304 unsigned long get_wchan(struct task_struct
*p
)
306 struct stack_frame
*sf
, *low
, *high
;
307 unsigned long return_address
;
310 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
|| !task_stack_page(p
))
312 low
= task_stack_page(p
);
313 high
= (struct stack_frame
*) task_pt_regs(p
);
314 sf
= (struct stack_frame
*) (p
->thread
.ksp
& PSW_ADDR_INSN
);
315 if (sf
<= low
|| sf
> high
)
317 for (count
= 0; count
< 16; count
++) {
318 sf
= (struct stack_frame
*) (sf
->back_chain
& PSW_ADDR_INSN
);
319 if (sf
<= low
|| sf
> high
)
321 return_address
= sf
->gprs
[8] & PSW_ADDR_INSN
;
322 if (!in_sched_functions(return_address
))
323 return return_address
;
328 unsigned long arch_align_stack(unsigned long sp
)
330 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
331 sp
-= get_random_int() & ~PAGE_MASK
;
335 static inline unsigned long brk_rnd(void)
337 /* 8MB for 32bit, 1GB for 64bit */
339 return (get_random_int() & 0x7ffUL
) << PAGE_SHIFT
;
341 return (get_random_int() & 0x3ffffUL
) << PAGE_SHIFT
;
344 unsigned long arch_randomize_brk(struct mm_struct
*mm
)
346 unsigned long ret
= PAGE_ALIGN(mm
->brk
+ brk_rnd());
353 unsigned long randomize_et_dyn(unsigned long base
)
355 unsigned long ret
= PAGE_ALIGN(base
+ brk_rnd());
357 if (!(current
->flags
& PF_RANDOMIZE
))