arch/s390/kernel/process.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This file handles the architecture dependent parts of process handling.
   4  *
   5  *    Copyright IBM Corp. 1999, 2009
   6  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
   7  *               Hartmut Penner <hp@de.ibm.com>,
   8  *               Denis Joseph Barrow,
   9  */
  10
  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>
  19 #include <linux/mm.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>
  33 #include <asm/io.h>
  34 #include <asm/processor.h>
  35 #include <asm/vtimer.h>
  36 #include <asm/exec.h>
  37 #include <asm/irq.h>
  38 #include <asm/nmi.h>
  39 #include <asm/smp.h>
  40 #include <asm/stacktrace.h>
  41 #include <asm/switch_to.h>
  42 #include <asm/runtime_instr.h>
  43 #include <asm/unwind.h>
  44 #include "entry.h"
  45
  46 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
  47
  48 extern void kernel_thread_starter(void);
  49
  50 void flush_thread(void)
  51 {
  52 }
  53
  54 void arch_setup_new_exec(void)
  55 {
  56         if (S390_lowcore.current_pid != current->pid) {
  57                 S390_lowcore.current_pid = current->pid;
  58                 if (test_facility(40))
  59                         lpp(&S390_lowcore.lpp);
  60         }
  61 }
  62
  63 void arch_release_task_struct(struct task_struct *tsk)
  64 {
  65         runtime_instr_release(tsk);
  66         guarded_storage_release(tsk);
  67 }
  68
  69 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
  70 {
  71         /*
  72          * Save the floating-point or vector register state of the current
  73          * task and set the CIF_FPU flag to lazy restore the FPU register
  74          * state when returning to user space.
  75          */
  76         save_fpu_regs();
  77
  78         memcpy(dst, src, arch_task_struct_size);
  79         dst->thread.fpu.regs = dst->thread.fpu.fprs;
  80         return 0;
  81 }
  82
  83 int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
  84                 unsigned long arg, struct task_struct *p, unsigned long tls)
  85 {
  86         struct fake_frame
  87         {
  88                 struct stack_frame sf;
  89                 struct pt_regs childregs;
  90         } *frame;
  91
  92         frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
  93         p->thread.ksp = (unsigned long) frame;
  94         /* Save access registers to new thread structure. */
  95         save_access_regs(&p->thread.acrs[0]);
  96         /* start new process with ar4 pointing to the correct address space */
  97         /* Don't copy debug registers */
  98         memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
  99         memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
 100         clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
 101         p->thread.per_flags = 0;
 102         /* Initialize per thread user and system timer values */
 103         p->thread.user_timer = 0;
 104         p->thread.guest_timer = 0;
 105         p->thread.system_timer = 0;
 106         p->thread.hardirq_timer = 0;
 107         p->thread.softirq_timer = 0;
 108         p->thread.last_break = 1;
 109
 110         frame->sf.back_chain = 0;
 111         /* new return point is ret_from_fork */
 112         frame->sf.gprs[8] = (unsigned long) ret_from_fork;
 113         /* fake return stack for resume(), don't go back to schedule */
 114         frame->sf.gprs[9] = (unsigned long) frame;
 115
 116         /* Store access registers to kernel stack of new process. */
 117         if (unlikely(p->flags & PF_KTHREAD)) {
 118                 /* kernel thread */
 119                 memset(&frame->childregs, 0, sizeof(struct pt_regs));
 120                 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
 121                                 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
 122                 frame->childregs.psw.addr =
 123                                 (unsigned long) kernel_thread_starter;
 124                 frame->childregs.gprs[9] = new_stackp; /* function */
 125                 frame->childregs.gprs[10] = arg;
 126                 frame->childregs.gprs[11] = (unsigned long) do_exit;
 127                 frame->childregs.orig_gpr2 = -1;
 128
 129                 return 0;
 130         }
 131         frame->childregs = *current_pt_regs();
 132         frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
 133         frame->childregs.flags = 0;
 134         if (new_stackp)
 135                 frame->childregs.gprs[15] = new_stackp;
 136
 137         /* Don't copy runtime instrumentation info */
 138         p->thread.ri_cb = NULL;
 139         frame->childregs.psw.mask &= ~PSW_MASK_RI;
 140         /* Don't copy guarded storage control block */
 141         p->thread.gs_cb = NULL;
 142         p->thread.gs_bc_cb = NULL;
 143
 144         /* Set a new TLS ?  */
 145         if (clone_flags & CLONE_SETTLS) {
 146                 if (is_compat_task()) {
 147                         p->thread.acrs[0] = (unsigned int)tls;
 148                 } else {
 149                         p->thread.acrs[0] = (unsigned int)(tls >> 32);
 150                         p->thread.acrs[1] = (unsigned int)tls;
 151                 }
 152         }
 153         return 0;
 154 }
 155
 156 asmlinkage void execve_tail(void)
 157 {
 158         current->thread.fpu.fpc = 0;
 159         asm volatile("sfpc %0" : : "d" (0));
 160 }
 161
 162 unsigned long get_wchan(struct task_struct *p)
 163 {
 164         struct unwind_state state;
 165         unsigned long ip = 0;
 166
 167         if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
 168                 return 0;
 169
 170         if (!try_get_task_stack(p))
 171                 return 0;
 172
 173         unwind_for_each_frame(&state, p, NULL, 0) {
 174                 if (state.stack_info.type != STACK_TYPE_TASK) {
 175                         ip = 0;
 176                         break;
 177                 }
 178
 179                 ip = unwind_get_return_address(&state);
 180                 if (!ip)
 181                         break;
 182
 183                 if (!in_sched_functions(ip))
 184                         break;
 185         }
 186
 187         put_task_stack(p);
 188         return ip;
 189 }
 190
 191 unsigned long arch_align_stack(unsigned long sp)
 192 {
 193         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 194                 sp -= get_random_int() & ~PAGE_MASK;
 195         return sp & ~0xf;
 196 }
 197
 198 static inline unsigned long brk_rnd(void)
 199 {
 200         return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
 201 }
 202
 203 unsigned long arch_randomize_brk(struct mm_struct *mm)
 204 {
 205         unsigned long ret;
 206
 207         ret = PAGE_ALIGN(mm->brk + brk_rnd());
 208         return (ret > mm->brk) ? ret : mm->brk;
 209 }