1 // SPDX-License-Identifier: GPL-2.0
3 * This file handles the architecture dependent parts of process handling.
5 * Copyright IBM Corp. 1999, 2009
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
7 * Hartmut Penner <hp@de.ibm.com>,
11 #include <linux/elf-randomize.h>
12 #include <linux/compiler.h>
13 #include <linux/cpu.h>
14 #include <linux/sched.h>
15 #include <linux/sched/debug.h>
16 #include <linux/sched/task.h>
17 #include <linux/sched/task_stack.h>
18 #include <linux/kernel.h>
20 #include <linux/elfcore.h>
21 #include <linux/smp.h>
22 #include <linux/slab.h>
23 #include <linux/interrupt.h>
24 #include <linux/tick.h>
25 #include <linux/personality.h>
26 #include <linux/syscalls.h>
27 #include <linux/compat.h>
28 #include <linux/kprobes.h>
29 #include <linux/random.h>
30 #include <linux/export.h>
31 #include <linux/init_task.h>
32 #include <linux/entry-common.h>
33 #include <asm/cpu_mf.h>
35 #include <asm/processor.h>
36 #include <asm/vtimer.h>
41 #include <asm/stacktrace.h>
42 #include <asm/switch_to.h>
43 #include <asm/runtime_instr.h>
44 #include <asm/unwind.h>
47 void ret_from_fork(void) asm("ret_from_fork");
49 void __ret_from_fork(struct task_struct *prev, struct pt_regs *regs)
51 void (*func)(void *arg);
55 if (!user_mode(regs)) {
57 func = (void *)regs->gprs[9];
58 func((void *)regs->gprs[10]);
60 clear_pt_regs_flag(regs, PIF_SYSCALL);
61 syscall_exit_to_user_mode(regs);
64 void flush_thread(void)
68 void arch_setup_new_exec(void)
70 if (S390_lowcore.current_pid != current->pid) {
71 S390_lowcore.current_pid = current->pid;
72 if (test_facility(40))
73 lpp(&S390_lowcore.lpp);
77 void arch_release_task_struct(struct task_struct *tsk)
79 runtime_instr_release(tsk);
80 guarded_storage_release(tsk);
83 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
86 * Save the floating-point or vector register state of the current
87 * task and set the CIF_FPU flag to lazy restore the FPU register
88 * state when returning to user space.
92 memcpy(dst, src, arch_task_struct_size);
93 dst->thread.fpu.regs = dst->thread.fpu.fprs;
97 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
99 unsigned long clone_flags = args->flags;
100 unsigned long new_stackp = args->stack;
101 unsigned long arg = args->stack_size;
102 unsigned long tls = args->tls;
105 struct stack_frame sf;
106 struct pt_regs childregs;
109 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
110 p->thread.ksp = (unsigned long) frame;
111 /* Save access registers to new thread structure. */
112 save_access_regs(&p->thread.acrs[0]);
113 /* start new process with ar4 pointing to the correct address space */
114 /* Don't copy debug registers */
115 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
116 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
117 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
118 p->thread.per_flags = 0;
119 /* Initialize per thread user and system timer values */
120 p->thread.user_timer = 0;
121 p->thread.guest_timer = 0;
122 p->thread.system_timer = 0;
123 p->thread.hardirq_timer = 0;
124 p->thread.softirq_timer = 0;
125 p->thread.last_break = 1;
127 frame->sf.back_chain = 0;
128 frame->sf.gprs[5] = (unsigned long)frame + sizeof(struct stack_frame);
129 frame->sf.gprs[6] = (unsigned long)p;
130 /* new return point is ret_from_fork */
131 frame->sf.gprs[8] = (unsigned long)ret_from_fork;
132 /* fake return stack for resume(), don't go back to schedule */
133 frame->sf.gprs[9] = (unsigned long)frame;
135 /* Store access registers to kernel stack of new process. */
136 if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
138 memset(&frame->childregs, 0, sizeof(struct pt_regs));
139 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
140 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
141 frame->childregs.psw.addr =
142 (unsigned long)__ret_from_fork;
143 frame->childregs.gprs[9] = new_stackp; /* function */
144 frame->childregs.gprs[10] = arg;
145 frame->childregs.orig_gpr2 = -1;
146 frame->childregs.last_break = 1;
149 frame->childregs = *current_pt_regs();
150 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
151 frame->childregs.flags = 0;
153 frame->childregs.gprs[15] = new_stackp;
155 /* Don't copy runtime instrumentation info */
156 p->thread.ri_cb = NULL;
157 frame->childregs.psw.mask &= ~PSW_MASK_RI;
158 /* Don't copy guarded storage control block */
159 p->thread.gs_cb = NULL;
160 p->thread.gs_bc_cb = NULL;
162 /* Set a new TLS ? */
163 if (clone_flags & CLONE_SETTLS) {
164 if (is_compat_task()) {
165 p->thread.acrs[0] = (unsigned int)tls;
167 p->thread.acrs[0] = (unsigned int)(tls >> 32);
168 p->thread.acrs[1] = (unsigned int)tls;
172 * s390 stores the svc return address in arch_data when calling
173 * sigreturn()/restart_syscall() via vdso. 1 means no valid address
176 p->restart_block.arch_data = 1;
180 void execve_tail(void)
182 current->thread.fpu.fpc = 0;
183 asm volatile("sfpc %0" : : "d" (0));
186 unsigned long __get_wchan(struct task_struct *p)
188 struct unwind_state state;
189 unsigned long ip = 0;
191 if (!task_stack_page(p))
194 if (!try_get_task_stack(p))
197 unwind_for_each_frame(&state, p, NULL, 0) {
198 if (state.stack_info.type != STACK_TYPE_TASK) {
203 ip = unwind_get_return_address(&state);
207 if (!in_sched_functions(ip))
215 unsigned long arch_align_stack(unsigned long sp)
217 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
218 sp -= get_random_int() & ~PAGE_MASK;
222 static inline unsigned long brk_rnd(void)
224 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
227 unsigned long arch_randomize_brk(struct mm_struct *mm)
231 ret = PAGE_ALIGN(mm->brk + brk_rnd());
232 return (ret > mm->brk) ? ret : mm->brk;