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)
64 extern void kernel_thread_starter(void);
67 * Free current thread data structures etc..
69 void exit_thread(void)
71 exit_thread_runtime_instr();
74 void flush_thread(void)
78 void release_thread(struct task_struct *dead_task)
83 void arch_release_task_struct(struct task_struct *tsk)
86 kfree(tsk->thread.vxrs);
90 int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
91 unsigned long arg, struct task_struct *p)
93 struct thread_info *ti;
96 struct stack_frame sf;
97 struct pt_regs childregs;
100 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
101 p->thread.ksp = (unsigned long) frame;
102 /* Save access registers to new thread structure. */
103 save_access_regs(&p->thread.acrs[0]);
104 /* start new process with ar4 pointing to the correct address space */
105 p->thread.mm_segment = get_fs();
106 /* Don't copy debug registers */
107 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
108 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
109 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
110 /* Initialize per thread user and system timer values */
111 ti = task_thread_info(p);
113 ti->system_timer = 0;
115 frame->sf.back_chain = 0;
116 /* new return point is ret_from_fork */
117 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
118 /* fake return stack for resume(), don't go back to schedule */
119 frame->sf.gprs[9] = (unsigned long) frame;
121 /* Store access registers to kernel stack of new process. */
122 if (unlikely(p->flags & PF_KTHREAD)) {
124 memset(&frame->childregs, 0, sizeof(struct pt_regs));
125 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
126 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
127 frame->childregs.psw.addr = PSW_ADDR_AMODE |
128 (unsigned long) kernel_thread_starter;
129 frame->childregs.gprs[9] = new_stackp; /* function */
130 frame->childregs.gprs[10] = arg;
131 frame->childregs.gprs[11] = (unsigned long) do_exit;
132 frame->childregs.orig_gpr2 = -1;
136 frame->childregs = *current_pt_regs();
137 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
138 frame->childregs.flags = 0;
140 frame->childregs.gprs[15] = new_stackp;
142 /* Don't copy runtime instrumentation info */
143 p->thread.ri_cb = NULL;
144 p->thread.ri_signum = 0;
145 frame->childregs.psw.mask &= ~PSW_MASK_RI;
149 * save fprs to current->thread.fp_regs to merge them with
150 * the emulated registers and then copy the result to the child.
152 save_fp_ctl(¤t->thread.fp_regs.fpc);
153 save_fp_regs(current->thread.fp_regs.fprs);
154 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
155 sizeof(s390_fp_regs));
156 /* Set a new TLS ? */
157 if (clone_flags & CLONE_SETTLS)
158 p->thread.acrs[0] = frame->childregs.gprs[6];
159 #else /* CONFIG_64BIT */
160 /* Save the fpu registers to new thread structure. */
161 save_fp_ctl(&p->thread.fp_regs.fpc);
162 save_fp_regs(p->thread.fp_regs.fprs);
163 p->thread.fp_regs.pad = 0;
164 p->thread.vxrs = NULL;
165 /* Set a new TLS ? */
166 if (clone_flags & CLONE_SETTLS) {
167 unsigned long tls = frame->childregs.gprs[6];
168 if (is_compat_task()) {
169 p->thread.acrs[0] = (unsigned int)tls;
171 p->thread.acrs[0] = (unsigned int)(tls >> 32);
172 p->thread.acrs[1] = (unsigned int)tls;
175 #endif /* CONFIG_64BIT */
179 asmlinkage void execve_tail(void)
181 current->thread.fp_regs.fpc = 0;
182 if (MACHINE_HAS_IEEE)
183 asm volatile("sfpc %0,%0" : : "d" (0));
187 * fill in the FPU structure for a core dump.
189 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
193 * save fprs to current->thread.fp_regs to merge them with
194 * the emulated registers and then copy the result to the dump.
196 save_fp_ctl(¤t->thread.fp_regs.fpc);
197 save_fp_regs(current->thread.fp_regs.fprs);
198 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
199 #else /* CONFIG_64BIT */
200 save_fp_ctl(&fpregs->fpc);
201 save_fp_regs(fpregs->fprs);
202 #endif /* CONFIG_64BIT */
205 EXPORT_SYMBOL(dump_fpu);
207 unsigned long get_wchan(struct task_struct *p)
209 struct stack_frame *sf, *low, *high;
210 unsigned long return_address;
213 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
215 low = task_stack_page(p);
216 high = (struct stack_frame *) task_pt_regs(p);
217 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
218 if (sf <= low || sf > high)
220 for (count = 0; count < 16; count++) {
221 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
222 if (sf <= low || sf > high)
224 return_address = sf->gprs[8] & PSW_ADDR_INSN;
225 if (!in_sched_functions(return_address))
226 return return_address;
231 unsigned long arch_align_stack(unsigned long sp)
233 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
234 sp -= get_random_int() & ~PAGE_MASK;
238 static inline unsigned long brk_rnd(void)
240 /* 8MB for 32bit, 1GB for 64bit */
242 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
244 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
247 unsigned long arch_randomize_brk(struct mm_struct *mm)
251 ret = PAGE_ALIGN(mm->brk + brk_rnd());
252 return (ret > mm->brk) ? ret : mm->brk;