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>
27 #include <asm/processor.h>
28 #include <asm/vtimer.h>
33 #include <asm/switch_to.h>
34 #include <asm/runtime_instr.h>
37 asmlinkage
void ret_from_fork(void) asm ("ret_from_fork");
40 * Return saved PC of a blocked thread. used in kernel/sched.
41 * resume in entry.S does not create a new stack frame, it
42 * just stores the registers %r6-%r15 to the frame given by
43 * schedule. We want to return the address of the caller of
44 * schedule, so we have to walk the backchain one time to
45 * find the frame schedule() store its return address.
47 unsigned long thread_saved_pc(struct task_struct
*tsk
)
49 struct stack_frame
*sf
, *low
, *high
;
51 if (!tsk
|| !task_stack_page(tsk
))
53 low
= task_stack_page(tsk
);
54 high
= (struct stack_frame
*) task_pt_regs(tsk
);
55 sf
= (struct stack_frame
*) (tsk
->thread
.ksp
& PSW_ADDR_INSN
);
56 if (sf
<= low
|| sf
> high
)
58 sf
= (struct stack_frame
*) (sf
->back_chain
& PSW_ADDR_INSN
);
59 if (sf
<= low
|| sf
> high
)
65 * The idle loop on a S390...
67 static void default_idle(void)
69 if (cpu_is_offline(smp_processor_id()))
77 if (test_thread_flag(TIF_MCCK_PENDING
)) {
82 /* Halt the cpu and keep track of cpu time accounting. */
89 tick_nohz_idle_enter();
91 while (!need_resched() && !test_thread_flag(TIF_MCCK_PENDING
))
94 tick_nohz_idle_exit();
95 if (test_thread_flag(TIF_MCCK_PENDING
))
97 schedule_preempt_disabled();
101 extern void __kprobes
kernel_thread_starter(void);
104 * Free current thread data structures etc..
106 void exit_thread(void)
108 exit_thread_runtime_instr();
111 void flush_thread(void)
115 void release_thread(struct task_struct
*dead_task
)
119 int copy_thread(unsigned long clone_flags
, unsigned long new_stackp
,
120 unsigned long arg
, struct task_struct
*p
)
122 struct thread_info
*ti
;
125 struct stack_frame sf
;
126 struct pt_regs childregs
;
129 frame
= container_of(task_pt_regs(p
), struct fake_frame
, childregs
);
130 p
->thread
.ksp
= (unsigned long) frame
;
131 /* Save access registers to new thread structure. */
132 save_access_regs(&p
->thread
.acrs
[0]);
133 /* start new process with ar4 pointing to the correct address space */
134 p
->thread
.mm_segment
= get_fs();
135 /* Don't copy debug registers */
136 memset(&p
->thread
.per_user
, 0, sizeof(p
->thread
.per_user
));
137 memset(&p
->thread
.per_event
, 0, sizeof(p
->thread
.per_event
));
138 clear_tsk_thread_flag(p
, TIF_SINGLE_STEP
);
139 clear_tsk_thread_flag(p
, TIF_PER_TRAP
);
140 /* Initialize per thread user and system timer values */
141 ti
= task_thread_info(p
);
143 ti
->system_timer
= 0;
145 frame
->sf
.back_chain
= 0;
146 /* new return point is ret_from_fork */
147 frame
->sf
.gprs
[8] = (unsigned long) ret_from_fork
;
148 /* fake return stack for resume(), don't go back to schedule */
149 frame
->sf
.gprs
[9] = (unsigned long) frame
;
151 /* Store access registers to kernel stack of new process. */
152 if (unlikely(p
->flags
& PF_KTHREAD
)) {
154 memset(&frame
->childregs
, 0, sizeof(struct pt_regs
));
155 frame
->childregs
.psw
.mask
= psw_kernel_bits
| PSW_MASK_DAT
|
156 PSW_MASK_IO
| PSW_MASK_EXT
| PSW_MASK_MCHECK
;
157 frame
->childregs
.psw
.addr
= PSW_ADDR_AMODE
|
158 (unsigned long) kernel_thread_starter
;
159 frame
->childregs
.gprs
[9] = new_stackp
; /* function */
160 frame
->childregs
.gprs
[10] = arg
;
161 frame
->childregs
.gprs
[11] = (unsigned long) do_exit
;
162 frame
->childregs
.orig_gpr2
= -1;
166 frame
->childregs
= *current_pt_regs();
167 frame
->childregs
.gprs
[2] = 0; /* child returns 0 on fork. */
169 frame
->childregs
.gprs
[15] = new_stackp
;
171 /* Don't copy runtime instrumentation info */
172 p
->thread
.ri_cb
= NULL
;
173 p
->thread
.ri_signum
= 0;
174 frame
->childregs
.psw
.mask
&= ~PSW_MASK_RI
;
178 * save fprs to current->thread.fp_regs to merge them with
179 * the emulated registers and then copy the result to the child.
181 save_fp_regs(¤t
->thread
.fp_regs
);
182 memcpy(&p
->thread
.fp_regs
, ¤t
->thread
.fp_regs
,
183 sizeof(s390_fp_regs
));
184 /* Set a new TLS ? */
185 if (clone_flags
& CLONE_SETTLS
)
186 p
->thread
.acrs
[0] = frame
->childregs
.gprs
[6];
187 #else /* CONFIG_64BIT */
188 /* Save the fpu registers to new thread structure. */
189 save_fp_regs(&p
->thread
.fp_regs
);
190 /* Set a new TLS ? */
191 if (clone_flags
& CLONE_SETTLS
) {
192 unsigned long tls
= frame
->childregs
.gprs
[6];
193 if (is_compat_task()) {
194 p
->thread
.acrs
[0] = (unsigned int)tls
;
196 p
->thread
.acrs
[0] = (unsigned int)(tls
>> 32);
197 p
->thread
.acrs
[1] = (unsigned int)tls
;
200 #endif /* CONFIG_64BIT */
204 asmlinkage
void execve_tail(void)
206 current
->thread
.fp_regs
.fpc
= 0;
207 if (MACHINE_HAS_IEEE
)
208 asm volatile("sfpc %0,%0" : : "d" (0));
212 * fill in the FPU structure for a core dump.
214 int dump_fpu (struct pt_regs
* regs
, s390_fp_regs
*fpregs
)
218 * save fprs to current->thread.fp_regs to merge them with
219 * the emulated registers and then copy the result to the dump.
221 save_fp_regs(¤t
->thread
.fp_regs
);
222 memcpy(fpregs
, ¤t
->thread
.fp_regs
, sizeof(s390_fp_regs
));
223 #else /* CONFIG_64BIT */
224 save_fp_regs(fpregs
);
225 #endif /* CONFIG_64BIT */
228 EXPORT_SYMBOL(dump_fpu
);
230 unsigned long get_wchan(struct task_struct
*p
)
232 struct stack_frame
*sf
, *low
, *high
;
233 unsigned long return_address
;
236 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
|| !task_stack_page(p
))
238 low
= task_stack_page(p
);
239 high
= (struct stack_frame
*) task_pt_regs(p
);
240 sf
= (struct stack_frame
*) (p
->thread
.ksp
& PSW_ADDR_INSN
);
241 if (sf
<= low
|| sf
> high
)
243 for (count
= 0; count
< 16; count
++) {
244 sf
= (struct stack_frame
*) (sf
->back_chain
& PSW_ADDR_INSN
);
245 if (sf
<= low
|| sf
> high
)
247 return_address
= sf
->gprs
[8] & PSW_ADDR_INSN
;
248 if (!in_sched_functions(return_address
))
249 return return_address
;
254 unsigned long arch_align_stack(unsigned long sp
)
256 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
257 sp
-= get_random_int() & ~PAGE_MASK
;
261 static inline unsigned long brk_rnd(void)
263 /* 8MB for 32bit, 1GB for 64bit */
265 return (get_random_int() & 0x7ffUL
) << PAGE_SHIFT
;
267 return (get_random_int() & 0x3ffffUL
) << PAGE_SHIFT
;
270 unsigned long arch_randomize_brk(struct mm_struct
*mm
)
272 unsigned long ret
= PAGE_ALIGN(mm
->brk
+ brk_rnd());
279 unsigned long randomize_et_dyn(unsigned long base
)
281 unsigned long ret
= PAGE_ALIGN(base
+ brk_rnd());
283 if (!(current
->flags
& PF_RANDOMIZE
))
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