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
  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         struct task_struct *tsk = current;
 186
 187         printk("CPU:    %d    %s\n", task_thread_info(tsk)->cpu, print_tainted());
 188         printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
 189                current->comm, task_pid_nr(current), (void *) tsk,
 190                (void *) tsk->thread.ksp);
 191
 192         show_registers(regs);
 193         /* Show stack backtrace if pt_regs is from kernel mode */
 194         if (!(regs->psw.mask & PSW_MASK_PSTATE))
 195                 show_trace(NULL, (unsigned long *) regs->gprs[15]);
 196 }
 197
 198 extern void kernel_thread_starter(void);
 199
 200 asm(
 201         ".align 4\n"
 202         "kernel_thread_starter:\n"
 203         "    la    2,0(10)\n"
 204         "    basr  14,9\n"
 205         "    la    2,0\n"
 206         "    br    11\n");
 207
 208 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 209 {
 210         struct pt_regs regs;
 211
 212         memset(&regs, 0, sizeof(regs));
 213         regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
 214         regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
 215         regs.gprs[9] = (unsigned long) fn;
 216         regs.gprs[10] = (unsigned long) arg;
 217         regs.gprs[11] = (unsigned long) do_exit;
 218         regs.orig_gpr2 = -1;
 219
 220         /* Ok, create the new process.. */
 221         return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
 222                        0, &regs, 0, NULL, NULL);
 223 }
 224
 225 /*
 226  * Free current thread data structures etc..
 227  */
 228 void exit_thread(void)
 229 {
 230 }
 231
 232 void flush_thread(void)
 233 {
 234         clear_used_math();
 235         clear_tsk_thread_flag(current, TIF_USEDFPU);
 236 }
 237
 238 void release_thread(struct task_struct *dead_task)
 239 {
 240 }
 241
 242 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
 243         unsigned long unused,
 244         struct task_struct * p, struct pt_regs * regs)
 245 {
 246         struct fake_frame
 247           {
 248             struct stack_frame sf;
 249             struct pt_regs childregs;
 250           } *frame;
 251
 252         frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
 253         p->thread.ksp = (unsigned long) frame;
 254         /* Store access registers to kernel stack of new process. */
 255         frame->childregs = *regs;
 256         frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
 257         frame->childregs.gprs[15] = new_stackp;
 258         frame->sf.back_chain = 0;
 259
 260         /* new return point is ret_from_fork */
 261         frame->sf.gprs[8] = (unsigned long) ret_from_fork;
 262
 263         /* fake return stack for resume(), don't go back to schedule */
 264         frame->sf.gprs[9] = (unsigned long) frame;
 265
 266         /* Save access registers to new thread structure. */
 267         save_access_regs(&p->thread.acrs[0]);
 268
 269 #ifndef CONFIG_64BIT
 270         /*
 271          * save fprs to current->thread.fp_regs to merge them with
 272          * the emulated registers and then copy the result to the child.
 273          */
 274         save_fp_regs(&current->thread.fp_regs);
 275         memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
 276                sizeof(s390_fp_regs));
 277         /* Set a new TLS ?  */
 278         if (clone_flags & CLONE_SETTLS)
 279                 p->thread.acrs[0] = regs->gprs[6];
 280 #else /* CONFIG_64BIT */
 281         /* Save the fpu registers to new thread structure. */
 282         save_fp_regs(&p->thread.fp_regs);
 283         /* Set a new TLS ?  */
 284         if (clone_flags & CLONE_SETTLS) {
 285                 if (test_thread_flag(TIF_31BIT)) {
 286                         p->thread.acrs[0] = (unsigned int) regs->gprs[6];
 287                 } else {
 288                         p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
 289                         p->thread.acrs[1] = (unsigned int) regs->gprs[6];
 290                 }
 291         }
 292 #endif /* CONFIG_64BIT */
 293         /* start new process with ar4 pointing to the correct address space */
 294         p->thread.mm_segment = get_fs();
 295         /* Don't copy debug registers */
 296         memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
 297
 298         return 0;
 299 }
 300
 301 asmlinkage long sys_fork(void)
 302 {
 303         struct pt_regs *regs = task_pt_regs(current);
 304         return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
 305 }
 306
 307 asmlinkage long sys_clone(void)
 308 {
 309         struct pt_regs *regs = task_pt_regs(current);
 310         unsigned long clone_flags;
 311         unsigned long newsp;
 312         int __user *parent_tidptr, *child_tidptr;
 313
 314         clone_flags = regs->gprs[3];
 315         newsp = regs->orig_gpr2;
 316         parent_tidptr = (int __user *) regs->gprs[4];
 317         child_tidptr = (int __user *) regs->gprs[5];
 318         if (!newsp)
 319                 newsp = regs->gprs[15];
 320         return do_fork(clone_flags, newsp, regs, 0,
 321                        parent_tidptr, child_tidptr);
 322 }
 323
 324 /*
 325  * This is trivial, and on the face of it looks like it
 326  * could equally well be done in user mode.
 327  *
 328  * Not so, for quite unobvious reasons - register pressure.
 329  * In user mode vfork() cannot have a stack frame, and if
 330  * done by calling the "clone()" system call directly, you
 331  * do not have enough call-clobbered registers to hold all
 332  * the information you need.
 333  */
 334 asmlinkage long sys_vfork(void)
 335 {
 336         struct pt_regs *regs = task_pt_regs(current);
 337         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
 338                        regs->gprs[15], regs, 0, NULL, NULL);
 339 }
 340
 341 asmlinkage void execve_tail(void)
 342 {
 343         task_lock(current);
 344         current->ptrace &= ~PT_DTRACE;
 345         task_unlock(current);
 346         current->thread.fp_regs.fpc = 0;
 347         if (MACHINE_HAS_IEEE)
 348                 asm volatile("sfpc %0,%0" : : "d" (0));
 349 }
 350
 351 /*
 352  * sys_execve() executes a new program.
 353  */
 354 asmlinkage long sys_execve(void)
 355 {
 356         struct pt_regs *regs = task_pt_regs(current);
 357         char *filename;
 358         unsigned long result;
 359         int rc;
 360
 361         filename = getname((char __user *) regs->orig_gpr2);
 362         if (IS_ERR(filename)) {
 363                 result = PTR_ERR(filename);
 364                 goto out;
 365         }
 366         rc = do_execve(filename, (char __user * __user *) regs->gprs[3],
 367                        (char __user * __user *) regs->gprs[4], regs);
 368         if (rc) {
 369                 result = rc;
 370                 goto out_putname;
 371         }
 372         execve_tail();
 373         result = regs->gprs[2];
 374 out_putname:
 375         putname(filename);
 376 out:
 377         return result;
 378 }
 379
 380 /*
 381  * fill in the FPU structure for a core dump.
 382  */
 383 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
 384 {
 385 #ifndef CONFIG_64BIT
 386         /*
 387          * save fprs to current->thread.fp_regs to merge them with
 388          * the emulated registers and then copy the result to the dump.
 389          */
 390         save_fp_regs(&current->thread.fp_regs);
 391         memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
 392 #else /* CONFIG_64BIT */
 393         save_fp_regs(fpregs);
 394 #endif /* CONFIG_64BIT */
 395         return 1;
 396 }
 397
 398 unsigned long get_wchan(struct task_struct *p)
 399 {
 400         struct stack_frame *sf, *low, *high;
 401         unsigned long return_address;
 402         int count;
 403
 404         if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
 405                 return 0;
 406         low = task_stack_page(p);
 407         high = (struct stack_frame *) task_pt_regs(p);
 408         sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
 409         if (sf <= low || sf > high)
 410                 return 0;
 411         for (count = 0; count < 16; count++) {
 412                 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
 413                 if (sf <= low || sf > high)
 414                         return 0;
 415                 return_address = sf->gprs[8] & PSW_ADDR_INSN;
 416                 if (!in_sched_functions(return_address))
 417                         return return_address;
 418         }
 419         return 0;
 420 }
 421