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,
121 struct task_struct *p, struct pt_regs *unused)
123 struct thread_info *ti;
126 struct stack_frame sf;
127 struct pt_regs childregs;
130 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
131 p->thread.ksp = (unsigned long) frame;
132 /* Save access registers to new thread structure. */
133 save_access_regs(&p->thread.acrs[0]);
134 /* start new process with ar4 pointing to the correct address space */
135 p->thread.mm_segment = get_fs();
136 /* Don't copy debug registers */
137 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
138 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
139 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
140 clear_tsk_thread_flag(p, TIF_PER_TRAP);
141 /* Initialize per thread user and system timer values */
142 ti = task_thread_info(p);
144 ti->system_timer = 0;
146 frame->sf.back_chain = 0;
147 /* new return point is ret_from_fork */
148 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
149 /* fake return stack for resume(), don't go back to schedule */
150 frame->sf.gprs[9] = (unsigned long) frame;
152 /* Store access registers to kernel stack of new process. */
153 if (unlikely(p->flags & PF_KTHREAD)) {
155 memset(&frame->childregs, 0, sizeof(struct pt_regs));
156 frame->childregs.psw.mask = psw_kernel_bits | PSW_MASK_DAT |
157 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
158 frame->childregs.psw.addr = PSW_ADDR_AMODE |
159 (unsigned long) kernel_thread_starter;
160 frame->childregs.gprs[9] = new_stackp; /* function */
161 frame->childregs.gprs[10] = arg;
162 frame->childregs.gprs[11] = (unsigned long) do_exit;
163 frame->childregs.orig_gpr2 = -1;
167 frame->childregs = *current_pt_regs();
168 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
170 frame->childregs.gprs[15] = new_stackp;
172 /* Don't copy runtime instrumentation info */
173 p->thread.ri_cb = NULL;
174 p->thread.ri_signum = 0;
175 frame->childregs.psw.mask &= ~PSW_MASK_RI;
179 * save fprs to current->thread.fp_regs to merge them with
180 * the emulated registers and then copy the result to the child.
182 save_fp_regs(¤t->thread.fp_regs);
183 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
184 sizeof(s390_fp_regs));
185 /* Set a new TLS ? */
186 if (clone_flags & CLONE_SETTLS)
187 p->thread.acrs[0] = frame->childregs.gprs[6];
188 #else /* CONFIG_64BIT */
189 /* Save the fpu registers to new thread structure. */
190 save_fp_regs(&p->thread.fp_regs);
191 /* Set a new TLS ? */
192 if (clone_flags & CLONE_SETTLS) {
193 unsigned long tls = frame->childregs.gprs[6];
194 if (is_compat_task()) {
195 p->thread.acrs[0] = (unsigned int)tls;
197 p->thread.acrs[0] = (unsigned int)(tls >> 32);
198 p->thread.acrs[1] = (unsigned int)tls;
201 #endif /* CONFIG_64BIT */
205 asmlinkage void execve_tail(void)
207 current->thread.fp_regs.fpc = 0;
208 if (MACHINE_HAS_IEEE)
209 asm volatile("sfpc %0,%0" : : "d" (0));
213 * fill in the FPU structure for a core dump.
215 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
219 * save fprs to current->thread.fp_regs to merge them with
220 * the emulated registers and then copy the result to the dump.
222 save_fp_regs(¤t->thread.fp_regs);
223 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
224 #else /* CONFIG_64BIT */
225 save_fp_regs(fpregs);
226 #endif /* CONFIG_64BIT */
229 EXPORT_SYMBOL(dump_fpu);
231 unsigned long get_wchan(struct task_struct *p)
233 struct stack_frame *sf, *low, *high;
234 unsigned long return_address;
237 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
239 low = task_stack_page(p);
240 high = (struct stack_frame *) task_pt_regs(p);
241 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
242 if (sf <= low || sf > high)
244 for (count = 0; count < 16; count++) {
245 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
246 if (sf <= low || sf > high)
248 return_address = sf->gprs[8] & PSW_ADDR_INSN;
249 if (!in_sched_functions(return_address))
250 return return_address;
255 unsigned long arch_align_stack(unsigned long sp)
257 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
258 sp -= get_random_int() & ~PAGE_MASK;
262 static inline unsigned long brk_rnd(void)
264 /* 8MB for 32bit, 1GB for 64bit */
266 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
268 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
271 unsigned long arch_randomize_brk(struct mm_struct *mm)
273 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
280 unsigned long randomize_et_dyn(unsigned long base)
282 unsigned long ret = PAGE_ALIGN(base + brk_rnd());
284 if (!(current->flags & PF_RANDOMIZE))