arch/s390/kernel/process.c

   1 /*
   2  *  arch/s390/kernel/process.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   7  *               Hartmut Penner (hp@de.ibm.com),
   8  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
   9  *
  10  *  Derived from "arch/i386/kernel/process.c"
  11  *    Copyright (C) 1995, Linus Torvalds
  12  */
  13
  14 /*
  15  * This file handles the architecture-dependent parts of process handling..
  16  */
  17
  18 #include <linux/compiler.h>
  19 #include <linux/cpu.h>
  20 #include <linux/errno.h>
  21 #include <linux/sched.h>
  22 #include <linux/kernel.h>
  23 #include <linux/mm.h>
  24 #include <linux/fs.h>
  25 #include <linux/smp.h>
  26 #include <linux/stddef.h>
  27 #include <linux/unistd.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/slab.h>
  30 #include <linux/vmalloc.h>
  31 #include <linux/user.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/delay.h>
  34 #include <linux/reboot.h>
  35 #include <linux/init.h>
  36 #include <linux/module.h>
  37 #include <linux/notifier.h>
  38 #include <linux/utsname.h>
  39 #include <asm/uaccess.h>
  40 #include <asm/pgtable.h>
  41 #include <asm/system.h>
  42 #include <asm/io.h>
  43 #include <asm/processor.h>
  44 #include <asm/irq.h>
  45 #include <asm/timer.h>
  46 #include <asm/cpu.h>
  47
  48 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
  49
  50 /*
  51  * Return saved PC of a blocked thread. used in kernel/sched.
  52  * resume in entry.S does not create a new stack frame, it
  53  * just stores the registers %r6-%r15 to the frame given by
  54  * schedule. We want to return the address of the caller of
  55  * schedule, so we have to walk the backchain one time to
  56  * find the frame schedule() store its return address.
  57  */
  58 unsigned long thread_saved_pc(struct task_struct *tsk)
  59 {
  60         struct stack_frame *sf, *low, *high;
  61
  62         if (!tsk || !task_stack_page(tsk))
  63                 return 0;
  64         low = task_stack_page(tsk);
  65         high = (struct stack_frame *) task_pt_regs(tsk);
  66         sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
  67         if (sf <= low || sf > high)
  68                 return 0;
  69         sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
  70         if (sf <= low || sf > high)
  71                 return 0;
  72         return sf->gprs[8];
  73 }
  74
  75 /*
  76  * Need to know about CPUs going idle?
  77  */
  78 static ATOMIC_NOTIFIER_HEAD(idle_chain);
  79
  80 int register_idle_notifier(struct notifier_block *nb)
  81 {
  82         return atomic_notifier_chain_register(&idle_chain, nb);
  83 }
  84 EXPORT_SYMBOL(register_idle_notifier);
  85
  86 int unregister_idle_notifier(struct notifier_block *nb)
  87 {
  88         return atomic_notifier_chain_unregister(&idle_chain, nb);
  89 }
  90 EXPORT_SYMBOL(unregister_idle_notifier);
  91
  92 void do_monitor_call(struct pt_regs *regs, long interruption_code)
  93 {
  94 #ifdef CONFIG_SMP
  95         struct s390_idle_data *idle;
  96
  97         idle = &__get_cpu_var(s390_idle);
  98         spin_lock(&idle->lock);
  99         idle->idle_time += get_clock() - idle->idle_enter;
 100         idle->in_idle = 0;
 101         spin_unlock(&idle->lock);
 102 #endif
 103         /* disable monitor call class 0 */
 104         __ctl_clear_bit(8, 15);
 105
 106         atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE,
 107                                    (void *)(long) smp_processor_id());
 108 }
 109
 110 extern void s390_handle_mcck(void);
 111 /*
 112  * The idle loop on a S390...
 113  */
 114 static void default_idle(void)
 115 {
 116         int cpu, rc;
 117 #ifdef CONFIG_SMP
 118         struct s390_idle_data *idle;
 119 #endif
 120
 121         /* CPU is going idle. */
 122         cpu = smp_processor_id();
 123
 124         local_irq_disable();
 125         if (need_resched()) {
 126                 local_irq_enable();
 127                 return;
 128         }
 129
 130         rc = atomic_notifier_call_chain(&idle_chain,
 131                                         S390_CPU_IDLE, (void *)(long) cpu);
 132         if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
 133                 BUG();
 134         if (rc != NOTIFY_OK) {
 135                 local_irq_enable();
 136                 return;
 137         }
 138
 139         /* enable monitor call class 0 */
 140         __ctl_set_bit(8, 15);
 141
 142 #ifdef CONFIG_HOTPLUG_CPU
 143         if (cpu_is_offline(cpu)) {
 144                 preempt_enable_no_resched();
 145                 cpu_die();
 146         }
 147 #endif
 148
 149         local_mcck_disable();
 150         if (test_thread_flag(TIF_MCCK_PENDING)) {
 151                 local_mcck_enable();
 152                 local_irq_enable();
 153                 s390_handle_mcck();
 154                 return;
 155         }
 156 #ifdef CONFIG_SMP
 157         idle = &__get_cpu_var(s390_idle);
 158         spin_lock(&idle->lock);
 159         idle->idle_count++;
 160         idle->in_idle = 1;
 161         idle->idle_enter = get_clock();
 162         spin_unlock(&idle->lock);
 163 #endif
 164         trace_hardirqs_on();
 165         /* Wait for external, I/O or machine check interrupt. */
 166         __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
 167                         PSW_MASK_IO | PSW_MASK_EXT);
 168 }
 169
 170 void cpu_idle(void)
 171 {
 172         for (;;) {
 173                 while (!need_resched())
 174                         default_idle();
 175
 176                 preempt_enable_no_resched();
 177                 schedule();
 178                 preempt_disable();
 179         }
 180 }
 181
 182 void show_regs(struct pt_regs *regs)
 183 {
 184         print_modules();
 185         printk("CPU: %d %s %s %.*s\n",
 186                task_thread_info(current)->cpu, print_tainted(),
 187                init_utsname()->release,
 188                (int)strcspn(init_utsname()->version, " "),
 189                init_utsname()->version);
 190         printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
 191                current->comm, current->pid, current,
 192                (void *) current->thread.ksp);
 193         show_registers(regs);
 194         /* Show stack backtrace if pt_regs is from kernel mode */
 195         if (!(regs->psw.mask & PSW_MASK_PSTATE))
 196                 show_trace(NULL, (unsigned long *) regs->gprs[15]);
 197 }
 198
 199 extern void kernel_thread_starter(void);
 200
 201 asm(
 202         ".align 4\n"
 203         "kernel_thread_starter:\n"
 204         "    la    2,0(10)\n"
 205         "    basr  14,9\n"
 206         "    la    2,0\n"
 207         "    br    11\n");
 208
 209 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 210 {
 211         struct pt_regs regs;
 212
 213         memset(&regs, 0, sizeof(regs));
 214         regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
 215         regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
 216         regs.gprs[9] = (unsigned long) fn;
 217         regs.gprs[10] = (unsigned long) arg;
 218         regs.gprs[11] = (unsigned long) do_exit;
 219         regs.orig_gpr2 = -1;
 220
 221         /* Ok, create the new process.. */
 222         return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
 223                        0, &regs, 0, NULL, NULL);
 224 }
 225
 226 /*
 227  * Free current thread data structures etc..
 228  */
 229 void exit_thread(void)
 230 {
 231 }
 232
 233 void flush_thread(void)
 234 {
 235         clear_used_math();
 236         clear_tsk_thread_flag(current, TIF_USEDFPU);
 237 }
 238
 239 void release_thread(struct task_struct *dead_task)
 240 {
 241 }
 242
 243 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
 244         unsigned long unused,
 245         struct task_struct * p, struct pt_regs * regs)
 246 {
 247         struct fake_frame
 248           {
 249             struct stack_frame sf;
 250             struct pt_regs childregs;
 251           } *frame;
 252
 253         frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
 254         p->thread.ksp = (unsigned long) frame;
 255         /* Store access registers to kernel stack of new process. */
 256         frame->childregs = *regs;
 257         frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
 258         frame->childregs.gprs[15] = new_stackp;
 259         frame->sf.back_chain = 0;
 260
 261         /* new return point is ret_from_fork */
 262         frame->sf.gprs[8] = (unsigned long) ret_from_fork;
 263
 264         /* fake return stack for resume(), don't go back to schedule */
 265         frame->sf.gprs[9] = (unsigned long) frame;
 266
 267         /* Save access registers to new thread structure. */
 268         save_access_regs(&p->thread.acrs[0]);
 269
 270 #ifndef CONFIG_64BIT
 271         /*
 272          * save fprs to current->thread.fp_regs to merge them with
 273          * the emulated registers and then copy the result to the child.
 274          */
 275         save_fp_regs(&current->thread.fp_regs);
 276         memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
 277                sizeof(s390_fp_regs));
 278         /* Set a new TLS ?  */
 279         if (clone_flags & CLONE_SETTLS)
 280                 p->thread.acrs[0] = regs->gprs[6];
 281 #else /* CONFIG_64BIT */
 282         /* Save the fpu registers to new thread structure. */
 283         save_fp_regs(&p->thread.fp_regs);
 284         /* Set a new TLS ?  */
 285         if (clone_flags & CLONE_SETTLS) {
 286                 if (test_thread_flag(TIF_31BIT)) {
 287                         p->thread.acrs[0] = (unsigned int) regs->gprs[6];
 288                 } else {
 289                         p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
 290                         p->thread.acrs[1] = (unsigned int) regs->gprs[6];
 291                 }
 292         }
 293 #endif /* CONFIG_64BIT */
 294         /* start new process with ar4 pointing to the correct address space */
 295         p->thread.mm_segment = get_fs();
 296         /* Don't copy debug registers */
 297         memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
 298
 299         return 0;
 300 }
 301
 302 asmlinkage long sys_fork(void)
 303 {
 304         struct pt_regs *regs = task_pt_regs(current);
 305         return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
 306 }
 307
 308 asmlinkage long sys_clone(void)
 309 {
 310         struct pt_regs *regs = task_pt_regs(current);
 311         unsigned long clone_flags;
 312         unsigned long newsp;
 313         int __user *parent_tidptr, *child_tidptr;
 314
 315         clone_flags = regs->gprs[3];
 316         newsp = regs->orig_gpr2;
 317         parent_tidptr = (int __user *) regs->gprs[4];
 318         child_tidptr = (int __user *) regs->gprs[5];
 319         if (!newsp)
 320                 newsp = regs->gprs[15];
 321         return do_fork(clone_flags, newsp, regs, 0,
 322                        parent_tidptr, child_tidptr);
 323 }
 324
 325 /*
 326  * This is trivial, and on the face of it looks like it
 327  * could equally well be done in user mode.
 328  *
 329  * Not so, for quite unobvious reasons - register pressure.
 330  * In user mode vfork() cannot have a stack frame, and if
 331  * done by calling the "clone()" system call directly, you
 332  * do not have enough call-clobbered registers to hold all
 333  * the information you need.
 334  */
 335 asmlinkage long sys_vfork(void)
 336 {
 337         struct pt_regs *regs = task_pt_regs(current);
 338         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
 339                        regs->gprs[15], regs, 0, NULL, NULL);
 340 }
 341
 342 asmlinkage void execve_tail(void)
 343 {
 344         task_lock(current);
 345         current->ptrace &= ~PT_DTRACE;
 346         task_unlock(current);
 347         current->thread.fp_regs.fpc = 0;
 348         if (MACHINE_HAS_IEEE)
 349                 asm volatile("sfpc %0,%0" : : "d" (0));
 350 }
 351
 352 /*
 353  * sys_execve() executes a new program.
 354  */
 355 asmlinkage long sys_execve(void)
 356 {
 357         struct pt_regs *regs = task_pt_regs(current);
 358         char *filename;
 359         unsigned long result;
 360         int rc;
 361
 362         filename = getname((char __user *) regs->orig_gpr2);
 363         if (IS_ERR(filename)) {
 364                 result = PTR_ERR(filename);
 365                 goto out;
 366         }
 367         rc = do_execve(filename, (char __user * __user *) regs->gprs[3],
 368                        (char __user * __user *) regs->gprs[4], regs);
 369         if (rc) {
 370                 result = rc;
 371                 goto out_putname;
 372         }
 373         execve_tail();
 374         result = regs->gprs[2];
 375 out_putname:
 376         putname(filename);
 377 out:
 378         return result;
 379 }
 380
 381 /*
 382  * fill in the FPU structure for a core dump.
 383  */
 384 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
 385 {
 386 #ifndef CONFIG_64BIT
 387         /*
 388          * save fprs to current->thread.fp_regs to merge them with
 389          * the emulated registers and then copy the result to the dump.
 390          */
 391         save_fp_regs(&current->thread.fp_regs);
 392         memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
 393 #else /* CONFIG_64BIT */
 394         save_fp_regs(fpregs);
 395 #endif /* CONFIG_64BIT */
 396         return 1;
 397 }
 398
 399 unsigned long get_wchan(struct task_struct *p)
 400 {
 401         struct stack_frame *sf, *low, *high;
 402         unsigned long return_address;
 403         int count;
 404
 405         if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
 406                 return 0;
 407         low = task_stack_page(p);
 408         high = (struct stack_frame *) task_pt_regs(p);
 409         sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
 410         if (sf <= low || sf > high)
 411                 return 0;
 412         for (count = 0; count < 16; count++) {
 413                 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
 414                 if (sf <= low || sf > high)
 415                         return 0;
 416                 return_address = sf->gprs[8] & PSW_ADDR_INSN;
 417                 if (!in_sched_functions(return_address))
 418                         return return_address;
 419         }
 420         return 0;
 421 }
 422