LXR linux/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
  46asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
  47
  48extern void kernel_thread_starter(void);
  49
  50void flush_thread(void)
  51{
  52}
  53
  54void 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
  63void arch_release_task_struct(struct task_struct *tsk)
  64{
  65        runtime_instr_release(tsk);
  66        guarded_storage_release(tsk);
  67}
  68
  69int 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
  83int 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        p->thread.mm_segment = get_fs();
  98        /* Don't copy debug registers */
  99        memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
 100        memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
 101        clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
 102        p->thread.per_flags = 0;
 103        /* Initialize per thread user and system timer values */
 104        p->thread.user_timer = 0;
 105        p->thread.guest_timer = 0;
 106        p->thread.system_timer = 0;
 107        p->thread.hardirq_timer = 0;
 108        p->thread.softirq_timer = 0;
 109        p->thread.last_break = 1;
 110
 111        frame->sf.back_chain = 0;
 112        /* new return point is ret_from_fork */
 113        frame->sf.gprs[8] = (unsigned long) ret_from_fork;
 114        /* fake return stack for resume(), don't go back to schedule */
 115        frame->sf.gprs[9] = (unsigned long) frame;
 116
 117        /* Store access registers to kernel stack of new process. */
 118        if (unlikely(p->flags & PF_KTHREAD)) {
 119                /* kernel thread */
 120                memset(&frame->childregs, 0, sizeof(struct pt_regs));
 121                frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
 122                                PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
 123                frame->childregs.psw.addr =
 124                                (unsigned long) kernel_thread_starter;
 125                frame->childregs.gprs[9] = new_stackp; /* function */
 126                frame->childregs.gprs[10] = arg;
 127                frame->childregs.gprs[11] = (unsigned long) do_exit;
 128                frame->childregs.orig_gpr2 = -1;
 129
 130                return 0;
 131        }
 132        frame->childregs = *current_pt_regs();
 133        frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
 134        frame->childregs.flags = 0;
 135        if (new_stackp)
 136                frame->childregs.gprs[15] = new_stackp;
 137
 138        /* Don't copy runtime instrumentation info */
 139        p->thread.ri_cb = NULL;
 140        frame->childregs.psw.mask &= ~PSW_MASK_RI;
 141        /* Don't copy guarded storage control block */
 142        p->thread.gs_cb = NULL;
 143        p->thread.gs_bc_cb = NULL;
 144
 145        /* Set a new TLS ?  */
 146        if (clone_flags & CLONE_SETTLS) {
 147                if (is_compat_task()) {
 148                        p->thread.acrs[0] = (unsigned int)tls;
 149                } else {
 150                        p->thread.acrs[0] = (unsigned int)(tls >> 32);
 151                        p->thread.acrs[1] = (unsigned int)tls;
 152                }
 153        }
 154        return 0;
 155}
 156
 157asmlinkage void execve_tail(void)
 158{
 159        current->thread.fpu.fpc = 0;
 160        asm volatile("sfpc %0" : : "d" (0));
 161}
 162
 163unsigned long get_wchan(struct task_struct *p)
 164{
 165        struct unwind_state state;
 166        unsigned long ip = 0;
 167
 168        if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
 169                return 0;
 170
 171        if (!try_get_task_stack(p))
 172                return 0;
 173
 174        unwind_for_each_frame(&state, p, NULL, 0) {
 175                if (state.stack_info.type != STACK_TYPE_TASK) {
 176                        ip = 0;
 177                        break;
 178                }
 179
 180                ip = unwind_get_return_address(&state);
 181                if (!ip)
 182                        break;
 183
 184                if (!in_sched_functions(ip))
 185                        break;
 186        }
 187
 188        put_task_stack(p);
 189        return ip;
 190}
 191
 192unsigned long arch_align_stack(unsigned long sp)
 193{
 194        if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 195                sp -= get_random_int() & ~PAGE_MASK;
 196        return sp & ~0xf;
 197}
 198
 199static inline unsigned long brk_rnd(void)
 200{
 201        return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
 202}
 203
 204unsigned long arch_randomize_brk(struct mm_struct *mm)
 205{
 206        unsigned long ret;
 207
 208        ret = PAGE_ALIGN(mm->brk + brk_rnd());
 209        return (ret > mm->brk) ? ret : mm->brk;
 210}
 211
 212void set_fs_fixup(void)
 213{
 214        struct pt_regs *regs = current_pt_regs();
 215        static bool warned;
 216
 217        set_fs(USER_DS);
 218        if (warned)
 219                return;
 220        WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code);
 221        show_registers(regs);
 222        warned = true;
 223}
 224