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 <asm/cpu_mf.h>
34 #include <asm/processor.h>
35 #include <asm/vtimer.h>
40 #include <asm/switch_to.h>
41 #include <asm/runtime_instr.h>
44 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
46 extern void kernel_thread_starter(void);
48 void flush_thread(void)
52 void arch_setup_new_exec(void)
54 if (S390_lowcore.current_pid != current->pid) {
55 S390_lowcore.current_pid = current->pid;
56 if (test_facility(40))
57 lpp(&S390_lowcore.lpp);
61 void arch_release_task_struct(struct task_struct *tsk)
63 runtime_instr_release(tsk);
64 guarded_storage_release(tsk);
67 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
70 * Save the floating-point or vector register state of the current
71 * task and set the CIF_FPU flag to lazy restore the FPU register
72 * state when returning to user space.
76 memcpy(dst, src, arch_task_struct_size);
77 dst->thread.fpu.regs = dst->thread.fpu.fprs;
80 * Don't transfer over the runtime instrumentation or the guarded
81 * storage control block pointers. These fields are cleared here instead
82 * of in copy_thread() to avoid premature freeing of associated memory
83 * on fork() failure. Wait to clear the RI flag because ->stack still
84 * refers to the source thread.
86 dst->thread.ri_cb = NULL;
87 dst->thread.gs_cb = NULL;
88 dst->thread.gs_bc_cb = NULL;
93 int copy_thread_tls(unsigned long clone_flags, unsigned long new_stackp,
94 unsigned long arg, struct task_struct *p, unsigned long tls)
98 struct stack_frame sf;
99 struct pt_regs childregs;
102 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
103 p->thread.ksp = (unsigned long) frame;
104 /* Save access registers to new thread structure. */
105 save_access_regs(&p->thread.acrs[0]);
106 /* start new process with ar4 pointing to the correct address space */
107 p->thread.mm_segment = get_fs();
108 /* Don't copy debug registers */
109 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
110 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
111 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
112 p->thread.per_flags = 0;
113 /* Initialize per thread user and system timer values */
114 p->thread.user_timer = 0;
115 p->thread.guest_timer = 0;
116 p->thread.system_timer = 0;
117 p->thread.hardirq_timer = 0;
118 p->thread.softirq_timer = 0;
120 frame->sf.back_chain = 0;
121 /* new return point is ret_from_fork */
122 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
123 /* fake return stack for resume(), don't go back to schedule */
124 frame->sf.gprs[9] = (unsigned long) frame;
126 /* Store access registers to kernel stack of new process. */
127 if (unlikely(p->flags & PF_KTHREAD)) {
129 memset(&frame->childregs, 0, sizeof(struct pt_regs));
130 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
131 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
132 frame->childregs.psw.addr =
133 (unsigned long) kernel_thread_starter;
134 frame->childregs.gprs[9] = new_stackp; /* function */
135 frame->childregs.gprs[10] = arg;
136 frame->childregs.gprs[11] = (unsigned long) do_exit;
137 frame->childregs.orig_gpr2 = -1;
141 frame->childregs = *current_pt_regs();
142 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
143 frame->childregs.flags = 0;
145 frame->childregs.gprs[15] = new_stackp;
147 * Clear the runtime instrumentation flag after the above childregs
148 * copy. The CB pointer was already cleared in arch_dup_task_struct().
150 frame->childregs.psw.mask &= ~PSW_MASK_RI;
152 /* Set a new TLS ? */
153 if (clone_flags & CLONE_SETTLS) {
154 if (is_compat_task()) {
155 p->thread.acrs[0] = (unsigned int)tls;
157 p->thread.acrs[0] = (unsigned int)(tls >> 32);
158 p->thread.acrs[1] = (unsigned int)tls;
164 asmlinkage void execve_tail(void)
166 current->thread.fpu.fpc = 0;
167 asm volatile("sfpc %0" : : "d" (0));
171 * fill in the FPU structure for a core dump.
173 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
176 fpregs->fpc = current->thread.fpu.fpc;
179 convert_vx_to_fp((freg_t *)&fpregs->fprs,
180 current->thread.fpu.vxrs);
182 memcpy(&fpregs->fprs, current->thread.fpu.fprs,
183 sizeof(fpregs->fprs));
186 EXPORT_SYMBOL(dump_fpu);
188 unsigned long get_wchan(struct task_struct *p)
190 struct stack_frame *sf, *low, *high;
191 unsigned long return_address;
194 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
197 if (!try_get_task_stack(p))
200 low = task_stack_page(p);
201 high = (struct stack_frame *) task_pt_regs(p);
202 sf = (struct stack_frame *) p->thread.ksp;
203 if (sf <= low || sf > high) {
207 for (count = 0; count < 16; count++) {
208 sf = (struct stack_frame *) sf->back_chain;
209 if (sf <= low || sf > high) {
213 return_address = sf->gprs[8];
214 if (!in_sched_functions(return_address))
219 return return_address;
222 unsigned long arch_align_stack(unsigned long sp)
224 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
225 sp -= get_random_int() & ~PAGE_MASK;
229 static inline unsigned long brk_rnd(void)
231 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
234 unsigned long arch_randomize_brk(struct mm_struct *mm)
238 ret = PAGE_ALIGN(mm->brk + brk_rnd());
239 return (ret > mm->brk) ? ret : mm->brk;
242 void set_fs_fixup(void)
244 struct pt_regs *regs = current_pt_regs();
250 WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code);
251 show_registers(regs);