arch/s390/kernel/process.c

   1 /*
   2  * This file handles the architecture dependent parts of process handling.
   3  *
   4  *    Copyright IBM Corp. 1999, 2009
   5  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
   6  *               Hartmut Penner <hp@de.ibm.com>,
   7  *               Denis Joseph Barrow,
   8  */
   9
  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>
  18 #include <linux/mm.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>
  31 #include <asm/io.h>
  32 #include <asm/processor.h>
  33 #include <asm/vtimer.h>
  34 #include <asm/exec.h>
  35 #include <asm/irq.h>
  36 #include <asm/nmi.h>
  37 #include <asm/smp.h>
  38 #include <asm/switch_to.h>
  39 #include <asm/runtime_instr.h>
  40 #include "entry.h"
  41
  42 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
  43
  44 extern void kernel_thread_starter(void);
  45
  46 void flush_thread(void)
  47 {
  48 }
  49
  50 void arch_release_task_struct(struct task_struct *tsk)
  51 {
  52         runtime_instr_release(tsk);
  53         guarded_storage_release(tsk);
  54 }
  55
  56 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
  57 {
  58         /*
  59          * Save the floating-point or vector register state of the current
  60          * task and set the CIF_FPU flag to lazy restore the FPU register
  61          * state when returning to user space.
  62          */
  63         save_fpu_regs();
  64
  65         memcpy(dst, src, arch_task_struct_size);
  66         dst->thread.fpu.regs = dst->thread.fpu.fprs;
  67         return 0;
  68 }
  69
  70 int copy_thread_tls(unsigned long clone_flags, unsigned long new_stackp,
  71                     unsigned long arg, struct task_struct *p, unsigned long tls)
  72 {
  73         struct fake_frame
  74         {
  75                 struct stack_frame sf;
  76                 struct pt_regs childregs;
  77         } *frame;
  78
  79         frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
  80         p->thread.ksp = (unsigned long) frame;
  81         /* Save access registers to new thread structure. */
  82         save_access_regs(&p->thread.acrs[0]);
  83         /* start new process with ar4 pointing to the correct address space */
  84         p->thread.mm_segment = get_fs();
  85         /* Don't copy debug registers */
  86         memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
  87         memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
  88         clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
  89         /* Initialize per thread user and system timer values */
  90         p->thread.user_timer = 0;
  91         p->thread.guest_timer = 0;
  92         p->thread.system_timer = 0;
  93         p->thread.hardirq_timer = 0;
  94         p->thread.softirq_timer = 0;
  95
  96         frame->sf.back_chain = 0;
  97         /* new return point is ret_from_fork */
  98         frame->sf.gprs[8] = (unsigned long) ret_from_fork;
  99         /* fake return stack for resume(), don't go back to schedule */
 100         frame->sf.gprs[9] = (unsigned long) frame;
 101
 102         /* Store access registers to kernel stack of new process. */
 103         if (unlikely(p->flags & PF_KTHREAD)) {
 104                 /* kernel thread */
 105                 memset(&frame->childregs, 0, sizeof(struct pt_regs));
 106                 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
 107                                 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
 108                 frame->childregs.psw.addr =
 109                                 (unsigned long) kernel_thread_starter;
 110                 frame->childregs.gprs[9] = new_stackp; /* function */
 111                 frame->childregs.gprs[10] = arg;
 112                 frame->childregs.gprs[11] = (unsigned long) do_exit;
 113                 frame->childregs.orig_gpr2 = -1;
 114
 115                 return 0;
 116         }
 117         frame->childregs = *current_pt_regs();
 118         frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
 119         frame->childregs.flags = 0;
 120         if (new_stackp)
 121                 frame->childregs.gprs[15] = new_stackp;
 122
 123         /* Don't copy runtime instrumentation info */
 124         p->thread.ri_cb = NULL;
 125         frame->childregs.psw.mask &= ~PSW_MASK_RI;
 126         /* Don't copy guarded storage control block */
 127         p->thread.gs_cb = NULL;
 128         p->thread.gs_bc_cb = NULL;
 129
 130         /* Set a new TLS ?  */
 131         if (clone_flags & CLONE_SETTLS) {
 132                 if (is_compat_task()) {
 133                         p->thread.acrs[0] = (unsigned int)tls;
 134                 } else {
 135                         p->thread.acrs[0] = (unsigned int)(tls >> 32);
 136                         p->thread.acrs[1] = (unsigned int)tls;
 137                 }
 138         }
 139         return 0;
 140 }
 141
 142 asmlinkage void execve_tail(void)
 143 {
 144         current->thread.fpu.fpc = 0;
 145         asm volatile("sfpc %0" : : "d" (0));
 146 }
 147
 148 /*
 149  * fill in the FPU structure for a core dump.
 150  */
 151 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
 152 {
 153         save_fpu_regs();
 154         fpregs->fpc = current->thread.fpu.fpc;
 155         fpregs->pad = 0;
 156         if (MACHINE_HAS_VX)
 157                 convert_vx_to_fp((freg_t *)&fpregs->fprs,
 158                                  current->thread.fpu.vxrs);
 159         else
 160                 memcpy(&fpregs->fprs, current->thread.fpu.fprs,
 161                        sizeof(fpregs->fprs));
 162         return 1;
 163 }
 164 EXPORT_SYMBOL(dump_fpu);
 165
 166 unsigned long get_wchan(struct task_struct *p)
 167 {
 168         struct stack_frame *sf, *low, *high;
 169         unsigned long return_address;
 170         int count;
 171
 172         if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
 173                 return 0;
 174         low = task_stack_page(p);
 175         high = (struct stack_frame *) task_pt_regs(p);
 176         sf = (struct stack_frame *) p->thread.ksp;
 177         if (sf <= low || sf > high)
 178                 return 0;
 179         for (count = 0; count < 16; count++) {
 180                 sf = (struct stack_frame *) sf->back_chain;
 181                 if (sf <= low || sf > high)
 182                         return 0;
 183                 return_address = sf->gprs[8];
 184                 if (!in_sched_functions(return_address))
 185                         return return_address;
 186         }
 187         return 0;
 188 }
 189
 190 unsigned long arch_align_stack(unsigned long sp)
 191 {
 192         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 193                 sp -= get_random_int() & ~PAGE_MASK;
 194         return sp & ~0xf;
 195 }
 196
 197 static inline unsigned long brk_rnd(void)
 198 {
 199         return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
 200 }
 201
 202 unsigned long arch_randomize_brk(struct mm_struct *mm)
 203 {
 204         unsigned long ret;
 205
 206         ret = PAGE_ALIGN(mm->brk + brk_rnd());
 207         return (ret > mm->brk) ? ret : mm->brk;
 208 }
 209
 210 void set_fs_fixup(void)
 211 {
 212         struct pt_regs *regs = current_pt_regs();
 213         static bool warned;
 214
 215         set_fs(USER_DS);
 216         if (warned)
 217                 return;
 218         WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code);
 219         show_registers(regs);
 220         warned = true;
 221 }