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/a.out.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/delay.h>
  35 #include <linux/reboot.h>
  36 #include <linux/init.h>
  37 #include <linux/module.h>
  38 #include <linux/notifier.h>
  39 #include <linux/utsname.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/pgtable.h>
  42 #include <asm/system.h>
  43 #include <asm/io.h>
  44 #include <asm/processor.h>
  45 #include <asm/irq.h>
  46 #include <asm/timer.h>
  47 #include <asm/cpu.h>
  48
  49 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
  50
  51 /*
  52  * Return saved PC of a blocked thread. used in kernel/sched.
  53  * resume in entry.S does not create a new stack frame, it
  54  * just stores the registers %r6-%r15 to the frame given by
  55  * schedule. We want to return the address of the caller of
  56  * schedule, so we have to walk the backchain one time to
  57  * find the frame schedule() store its return address.
  58  */
  59 unsigned long thread_saved_pc(struct task_struct *tsk)
  60 {
  61         struct stack_frame *sf, *low, *high;
  62
  63         if (!tsk || !task_stack_page(tsk))
  64                 return 0;
  65         low = task_stack_page(tsk);
  66         high = (struct stack_frame *) task_pt_regs(tsk);
  67         sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
  68         if (sf <= low || sf > high)
  69                 return 0;
  70         sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
  71         if (sf <= low || sf > high)
  72                 return 0;
  73         return sf->gprs[8];
  74 }
  75
  76 /*
  77  * Need to know about CPUs going idle?
  78  */
  79 static ATOMIC_NOTIFIER_HEAD(idle_chain);
  80
  81 int register_idle_notifier(struct notifier_block *nb)
  82 {
  83         return atomic_notifier_chain_register(&idle_chain, nb);
  84 }
  85 EXPORT_SYMBOL(register_idle_notifier);
  86
  87 int unregister_idle_notifier(struct notifier_block *nb)
  88 {
  89         return atomic_notifier_chain_unregister(&idle_chain, nb);
  90 }
  91 EXPORT_SYMBOL(unregister_idle_notifier);
  92
  93 void do_monitor_call(struct pt_regs *regs, long interruption_code)
  94 {
  95 #ifdef CONFIG_SMP
  96         struct s390_idle_data *idle;
  97
  98         idle = &__get_cpu_var(s390_idle);
  99         spin_lock(&idle->lock);
 100         idle->idle_time += get_clock() - idle->idle_enter;
 101         idle->in_idle = 0;
 102         spin_unlock(&idle->lock);
 103 #endif
 104         /* disable monitor call class 0 */
 105         __ctl_clear_bit(8, 15);
 106
 107         atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE,
 108                                    (void *)(long) smp_processor_id());
 109 }
 110
 111 extern void s390_handle_mcck(void);
 112 /*
 113  * The idle loop on a S390...
 114  */
 115 static void default_idle(void)
 116 {
 117         int cpu, rc;
 118 #ifdef CONFIG_SMP
 119         struct s390_idle_data *idle;
 120 #endif
 121
 122         /* CPU is going idle. */
 123         cpu = smp_processor_id();
 124
 125         local_irq_disable();
 126         if (need_resched()) {
 127                 local_irq_enable();
 128                 return;
 129         }
 130
 131         rc = atomic_notifier_call_chain(&idle_chain,
 132                                         S390_CPU_IDLE, (void *)(long) cpu);
 133         if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
 134                 BUG();
 135         if (rc != NOTIFY_OK) {
 136                 local_irq_enable();
 137                 return;
 138         }
 139
 140         /* enable monitor call class 0 */
 141         __ctl_set_bit(8, 15);
 142
 143 #ifdef CONFIG_HOTPLUG_CPU
 144         if (cpu_is_offline(cpu)) {
 145                 preempt_enable_no_resched();
 146                 cpu_die();
 147         }
 148 #endif
 149
 150         local_mcck_disable();
 151         if (test_thread_flag(TIF_MCCK_PENDING)) {
 152                 local_mcck_enable();
 153                 local_irq_enable();
 154                 s390_handle_mcck();
 155                 return;
 156         }
 157 #ifdef CONFIG_SMP
 158         idle = &__get_cpu_var(s390_idle);
 159         spin_lock(&idle->lock);
 160         idle->idle_count++;
 161         idle->in_idle = 1;
 162         idle->idle_enter = get_clock();
 163         spin_unlock(&idle->lock);
 164 #endif
 165         trace_hardirqs_on();
 166         /* Wait for external, I/O or machine check interrupt. */
 167         __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
 168                         PSW_MASK_IO | PSW_MASK_EXT);
 169 }
 170
 171 void cpu_idle(void)
 172 {
 173         for (;;) {
 174                 while (!need_resched())
 175                         default_idle();
 176
 177                 preempt_enable_no_resched();
 178                 schedule();
 179                 preempt_disable();
 180         }
 181 }
 182
 183 void show_regs(struct pt_regs *regs)
 184 {
 185         print_modules();
 186         printk("CPU: %d %s %s %.*s\n",
 187                task_thread_info(current)->cpu, print_tainted(),
 188                init_utsname()->release,
 189                (int)strcspn(init_utsname()->version, " "),
 190                init_utsname()->version);
 191         printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
 192                current->comm, current->pid, current,
 193                (void *) current->thread.ksp);
 194         show_registers(regs);
 195         /* Show stack backtrace if pt_regs is from kernel mode */
 196         if (!(regs->psw.mask & PSW_MASK_PSTATE))
 197                 show_trace(NULL, (unsigned long *) regs->gprs[15]);
 198 }
 199
 200 extern void kernel_thread_starter(void);
 201
 202 asm(
 203         ".align 4\n"
 204         "kernel_thread_starter:\n"
 205         "    la    2,0(10)\n"
 206         "    basr  14,9\n"
 207         "    la    2,0\n"
 208         "    br    11\n");
 209
 210 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 211 {
 212         struct pt_regs regs;
 213
 214         memset(&regs, 0, sizeof(regs));
 215         regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
 216         regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
 217         regs.gprs[9] = (unsigned long) fn;
 218         regs.gprs[10] = (unsigned long) arg;
 219         regs.gprs[11] = (unsigned long) do_exit;
 220         regs.orig_gpr2 = -1;
 221
 222         /* Ok, create the new process.. */
 223         return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
 224                        0, &regs, 0, NULL, NULL);
 225 }
 226
 227 /*
 228  * Free current thread data structures etc..
 229  */
 230 void exit_thread(void)
 231 {
 232 }
 233
 234 void flush_thread(void)
 235 {
 236         clear_used_math();
 237         clear_tsk_thread_flag(current, TIF_USEDFPU);
 238 }
 239
 240 void release_thread(struct task_struct *dead_task)
 241 {
 242 }
 243
 244 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
 245         unsigned long unused,
 246         struct task_struct * p, struct pt_regs * regs)
 247 {
 248         struct fake_frame
 249           {
 250             struct stack_frame sf;
 251             struct pt_regs childregs;
 252           } *frame;
 253
 254         frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
 255         p->thread.ksp = (unsigned long) frame;
 256         /* Store access registers to kernel stack of new process. */
 257         frame->childregs = *regs;
 258         frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
 259         frame->childregs.gprs[15] = new_stackp;
 260         frame->sf.back_chain = 0;
 261
 262         /* new return point is ret_from_fork */
 263         frame->sf.gprs[8] = (unsigned long) ret_from_fork;
 264
 265         /* fake return stack for resume(), don't go back to schedule */
 266         frame->sf.gprs[9] = (unsigned long) frame;
 267
 268         /* Save access registers to new thread structure. */
 269         save_access_regs(&p->thread.acrs[0]);
 270
 271 #ifndef CONFIG_64BIT
 272         /*
 273          * save fprs to current->thread.fp_regs to merge them with
 274          * the emulated registers and then copy the result to the child.
 275          */
 276         save_fp_regs(&current->thread.fp_regs);
 277         memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
 278                sizeof(s390_fp_regs));
 279         /* Set a new TLS ?  */
 280         if (clone_flags & CLONE_SETTLS)
 281                 p->thread.acrs[0] = regs->gprs[6];
 282 #else /* CONFIG_64BIT */
 283         /* Save the fpu registers to new thread structure. */
 284         save_fp_regs(&p->thread.fp_regs);
 285         /* Set a new TLS ?  */
 286         if (clone_flags & CLONE_SETTLS) {
 287                 if (test_thread_flag(TIF_31BIT)) {
 288                         p->thread.acrs[0] = (unsigned int) regs->gprs[6];
 289                 } else {
 290                         p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
 291                         p->thread.acrs[1] = (unsigned int) regs->gprs[6];
 292                 }
 293         }
 294 #endif /* CONFIG_64BIT */
 295         /* start new process with ar4 pointing to the correct address space */
 296         p->thread.mm_segment = get_fs();
 297         /* Don't copy debug registers */
 298         memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
 299
 300         return 0;
 301 }
 302
 303 asmlinkage long sys_fork(void)
 304 {
 305         struct pt_regs *regs = task_pt_regs(current);
 306         return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
 307 }
 308
 309 asmlinkage long sys_clone(void)
 310 {
 311         struct pt_regs *regs = task_pt_regs(current);
 312         unsigned long clone_flags;
 313         unsigned long newsp;
 314         int __user *parent_tidptr, *child_tidptr;
 315
 316         clone_flags = regs->gprs[3];
 317         newsp = regs->orig_gpr2;
 318         parent_tidptr = (int __user *) regs->gprs[4];
 319         child_tidptr = (int __user *) regs->gprs[5];
 320         if (!newsp)
 321                 newsp = regs->gprs[15];
 322         return do_fork(clone_flags, newsp, regs, 0,
 323                        parent_tidptr, child_tidptr);
 324 }
 325
 326 /*
 327  * This is trivial, and on the face of it looks like it
 328  * could equally well be done in user mode.
 329  *
 330  * Not so, for quite unobvious reasons - register pressure.
 331  * In user mode vfork() cannot have a stack frame, and if
 332  * done by calling the "clone()" system call directly, you
 333  * do not have enough call-clobbered registers to hold all
 334  * the information you need.
 335  */
 336 asmlinkage long sys_vfork(void)
 337 {
 338         struct pt_regs *regs = task_pt_regs(current);
 339         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
 340                        regs->gprs[15], regs, 0, NULL, NULL);
 341 }
 342
 343 asmlinkage void execve_tail(void)
 344 {
 345         task_lock(current);
 346         current->ptrace &= ~PT_DTRACE;
 347         task_unlock(current);
 348         current->thread.fp_regs.fpc = 0;
 349         if (MACHINE_HAS_IEEE)
 350                 asm volatile("sfpc %0,%0" : : "d" (0));
 351 }
 352
 353 /*
 354  * sys_execve() executes a new program.
 355  */
 356 asmlinkage long sys_execve(void)
 357 {
 358         struct pt_regs *regs = task_pt_regs(current);
 359         char *filename;
 360         unsigned long result;
 361         int rc;
 362
 363         filename = getname((char __user *) regs->orig_gpr2);
 364         if (IS_ERR(filename)) {
 365                 result = PTR_ERR(filename);
 366                 goto out;
 367         }
 368         rc = do_execve(filename, (char __user * __user *) regs->gprs[3],
 369                        (char __user * __user *) regs->gprs[4], regs);
 370         if (rc) {
 371                 result = rc;
 372                 goto out_putname;
 373         }
 374         execve_tail();
 375         result = regs->gprs[2];
 376 out_putname:
 377         putname(filename);
 378 out:
 379         return result;
 380 }
 381
 382 /*
 383  * fill in the FPU structure for a core dump.
 384  */
 385 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
 386 {
 387 #ifndef CONFIG_64BIT
 388         /*
 389          * save fprs to current->thread.fp_regs to merge them with
 390          * the emulated registers and then copy the result to the dump.
 391          */
 392         save_fp_regs(&current->thread.fp_regs);
 393         memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
 394 #else /* CONFIG_64BIT */
 395         save_fp_regs(fpregs);
 396 #endif /* CONFIG_64BIT */
 397         return 1;
 398 }
 399
 400 unsigned long get_wchan(struct task_struct *p)
 401 {
 402         struct stack_frame *sf, *low, *high;
 403         unsigned long return_address;
 404         int count;
 405
 406         if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
 407                 return 0;
 408         low = task_stack_page(p);
 409         high = (struct stack_frame *) task_pt_regs(p);
 410         sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
 411         if (sf <= low || sf > high)
 412                 return 0;
 413         for (count = 0; count < 16; count++) {
 414                 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
 415                 if (sf <= low || sf > high)
 416                         return 0;
 417                 return_address = sf->gprs[8] & PSW_ADDR_INSN;
 418                 if (!in_sched_functions(return_address))
 419                         return return_address;
 420         }
 421         return 0;
 422 }
 423