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/elf-randomize.h>
11 #include <linux/compiler.h>
12 #include <linux/cpu.h>
13 #include <linux/sched.h>
14 #include <linux/sched/debug.h>
15 #include <linux/sched/task.h>
16 #include <linux/sched/task_stack.h>
17 #include <linux/kernel.h>
19 #include <linux/elfcore.h>
20 #include <linux/smp.h>
21 #include <linux/slab.h>
22 #include <linux/interrupt.h>
23 #include <linux/tick.h>
24 #include <linux/personality.h>
25 #include <linux/syscalls.h>
26 #include <linux/compat.h>
27 #include <linux/kprobes.h>
28 #include <linux/random.h>
29 #include <linux/export.h>
30 #include <linux/init_task.h>
32 #include <asm/processor.h>
33 #include <asm/vtimer.h>
38 #include <asm/switch_to.h>
39 #include <asm/runtime_instr.h>
42 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
45 * Return saved PC of a blocked thread. used in kernel/sched.
46 * resume in entry.S does not create a new stack frame, it
47 * just stores the registers %r6-%r15 to the frame given by
48 * schedule. We want to return the address of the caller of
49 * schedule, so we have to walk the backchain one time to
50 * find the frame schedule() store its return address.
52 unsigned long thread_saved_pc(struct task_struct *tsk)
54 struct stack_frame *sf, *low, *high;
56 if (!tsk || !task_stack_page(tsk))
58 low = task_stack_page(tsk);
59 high = (struct stack_frame *) task_pt_regs(tsk);
60 sf = (struct stack_frame *) tsk->thread.ksp;
61 if (sf <= low || sf > high)
63 sf = (struct stack_frame *) sf->back_chain;
64 if (sf <= low || sf > high)
69 extern void kernel_thread_starter(void);
72 * Free current thread data structures etc..
74 void exit_thread(struct task_struct *tsk)
77 exit_thread_runtime_instr();
80 void flush_thread(void)
84 void release_thread(struct task_struct *dead_task)
88 void arch_release_task_struct(struct task_struct *tsk)
92 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
95 * Save the floating-point or vector register state of the current
96 * task and set the CIF_FPU flag to lazy restore the FPU register
97 * state when returning to user space.
101 memcpy(dst, src, arch_task_struct_size);
102 dst->thread.fpu.regs = dst->thread.fpu.fprs;
106 int copy_thread_tls(unsigned long clone_flags, unsigned long new_stackp,
107 unsigned long arg, struct task_struct *p, unsigned long tls)
111 struct stack_frame sf;
112 struct pt_regs childregs;
115 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
116 p->thread.ksp = (unsigned long) frame;
117 /* Save access registers to new thread structure. */
118 save_access_regs(&p->thread.acrs[0]);
119 /* start new process with ar4 pointing to the correct address space */
120 p->thread.mm_segment = get_fs();
121 /* Don't copy debug registers */
122 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
123 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
124 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
125 /* Initialize per thread user and system timer values */
126 p->thread.user_timer = 0;
127 p->thread.guest_timer = 0;
128 p->thread.system_timer = 0;
129 p->thread.hardirq_timer = 0;
130 p->thread.softirq_timer = 0;
132 frame->sf.back_chain = 0;
133 /* new return point is ret_from_fork */
134 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
135 /* fake return stack for resume(), don't go back to schedule */
136 frame->sf.gprs[9] = (unsigned long) frame;
138 /* Store access registers to kernel stack of new process. */
139 if (unlikely(p->flags & PF_KTHREAD)) {
141 memset(&frame->childregs, 0, sizeof(struct pt_regs));
142 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
143 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
144 frame->childregs.psw.addr =
145 (unsigned long) kernel_thread_starter;
146 frame->childregs.gprs[9] = new_stackp; /* function */
147 frame->childregs.gprs[10] = arg;
148 frame->childregs.gprs[11] = (unsigned long) do_exit;
149 frame->childregs.orig_gpr2 = -1;
153 frame->childregs = *current_pt_regs();
154 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
155 frame->childregs.flags = 0;
157 frame->childregs.gprs[15] = new_stackp;
159 /* Don't copy runtime instrumentation info */
160 p->thread.ri_cb = NULL;
161 frame->childregs.psw.mask &= ~PSW_MASK_RI;
163 /* Set a new TLS ? */
164 if (clone_flags & CLONE_SETTLS) {
165 if (is_compat_task()) {
166 p->thread.acrs[0] = (unsigned int)tls;
168 p->thread.acrs[0] = (unsigned int)(tls >> 32);
169 p->thread.acrs[1] = (unsigned int)tls;
175 asmlinkage void execve_tail(void)
177 current->thread.fpu.fpc = 0;
178 asm volatile("sfpc %0" : : "d" (0));
182 * fill in the FPU structure for a core dump.
184 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
187 fpregs->fpc = current->thread.fpu.fpc;
190 convert_vx_to_fp((freg_t *)&fpregs->fprs,
191 current->thread.fpu.vxrs);
193 memcpy(&fpregs->fprs, current->thread.fpu.fprs,
194 sizeof(fpregs->fprs));
197 EXPORT_SYMBOL(dump_fpu);
199 unsigned long get_wchan(struct task_struct *p)
201 struct stack_frame *sf, *low, *high;
202 unsigned long return_address;
205 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
207 low = task_stack_page(p);
208 high = (struct stack_frame *) task_pt_regs(p);
209 sf = (struct stack_frame *) p->thread.ksp;
210 if (sf <= low || sf > high)
212 for (count = 0; count < 16; count++) {
213 sf = (struct stack_frame *) sf->back_chain;
214 if (sf <= low || sf > high)
216 return_address = sf->gprs[8];
217 if (!in_sched_functions(return_address))
218 return return_address;
223 unsigned long arch_align_stack(unsigned long sp)
225 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
226 sp -= get_random_int() & ~PAGE_MASK;
230 static inline unsigned long brk_rnd(void)
232 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
235 unsigned long arch_randomize_brk(struct mm_struct *mm)
239 ret = PAGE_ALIGN(mm->brk + brk_rnd());
240 return (ret > mm->brk) ? ret : mm->brk;
243 void set_fs_fixup(void)
245 struct pt_regs *regs = current_pt_regs();
251 WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code);
252 show_registers(regs);