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/config.h>
  19 #include <linux/compiler.h>
  20 #include <linux/cpu.h>
  21 #include <linux/errno.h>
  22 #include <linux/sched.h>
  23 #include <linux/kernel.h>
  24 #include <linux/mm.h>
  25 #include <linux/smp.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/stddef.h>
  28 #include <linux/unistd.h>
  29 #include <linux/ptrace.h>
  30 #include <linux/slab.h>
  31 #include <linux/vmalloc.h>
  32 #include <linux/user.h>
  33 #include <linux/a.out.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/delay.h>
  36 #include <linux/reboot.h>
  37 #include <linux/init.h>
  38 #include <linux/module.h>
  39 #include <linux/notifier.h>
  40
  41 #include <asm/uaccess.h>
  42 #include <asm/pgtable.h>
  43 #include <asm/system.h>
  44 #include <asm/io.h>
  45 #include <asm/processor.h>
  46 #include <asm/irq.h>
  47 #include <asm/timer.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 struct notifier_block *idle_chain;
  80
  81 int register_idle_notifier(struct notifier_block *nb)
  82 {
  83         return 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 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         /* disable monitor call class 0 */
  96         __ctl_clear_bit(8, 15);
  97
  98         notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
  99                             (void *)(long) smp_processor_id());
 100 }
 101
 102 extern void s390_handle_mcck(void);
 103 /*
 104  * The idle loop on a S390...
 105  */
 106 void default_idle(void)
 107 {
 108         int cpu, rc;
 109
 110         /* CPU is going idle. */
 111         cpu = smp_processor_id();
 112
 113         local_irq_disable();
 114         if (need_resched()) {
 115                 local_irq_enable();
 116                 return;
 117         }
 118
 119         rc = notifier_call_chain(&idle_chain, CPU_IDLE, (void *)(long) cpu);
 120         if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
 121                 BUG();
 122         if (rc != NOTIFY_OK) {
 123                 local_irq_enable();
 124                 return;
 125         }
 126
 127         /* enable monitor call class 0 */
 128         __ctl_set_bit(8, 15);
 129
 130 #ifdef CONFIG_HOTPLUG_CPU
 131         if (cpu_is_offline(cpu)) {
 132                 preempt_enable_no_resched();
 133                 cpu_die();
 134         }
 135 #endif
 136
 137         local_mcck_disable();
 138         if (test_thread_flag(TIF_MCCK_PENDING)) {
 139                 local_mcck_enable();
 140                 local_irq_enable();
 141                 s390_handle_mcck();
 142                 return;
 143         }
 144
 145         /* Wait for external, I/O or machine check interrupt. */
 146         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_WAIT |
 147                         PSW_MASK_IO | PSW_MASK_EXT);
 148 }
 149
 150 void cpu_idle(void)
 151 {
 152         for (;;) {
 153                 while (!need_resched())
 154                         default_idle();
 155
 156                 preempt_enable_no_resched();
 157                 schedule();
 158                 preempt_disable();
 159         }
 160 }
 161
 162 void show_regs(struct pt_regs *regs)
 163 {
 164         struct task_struct *tsk = current;
 165
 166         printk("CPU:    %d    %s\n", task_thread_info(tsk)->cpu, print_tainted());
 167         printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
 168                current->comm, current->pid, (void *) tsk,
 169                (void *) tsk->thread.ksp);
 170
 171         show_registers(regs);
 172         /* Show stack backtrace if pt_regs is from kernel mode */
 173         if (!(regs->psw.mask & PSW_MASK_PSTATE))
 174                 show_trace(0,(unsigned long *) regs->gprs[15]);
 175 }
 176
 177 extern void kernel_thread_starter(void);
 178
 179 __asm__(".align 4\n"
 180         "kernel_thread_starter:\n"
 181         "    la    2,0(10)\n"
 182         "    basr  14,9\n"
 183         "    la    2,0\n"
 184         "    br    11\n");
 185
 186 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 187 {
 188         struct pt_regs regs;
 189
 190         memset(&regs, 0, sizeof(regs));
 191         regs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
 192         regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
 193         regs.gprs[9] = (unsigned long) fn;
 194         regs.gprs[10] = (unsigned long) arg;
 195         regs.gprs[11] = (unsigned long) do_exit;
 196         regs.orig_gpr2 = -1;
 197
 198         /* Ok, create the new process.. */
 199         return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
 200                        0, &regs, 0, NULL, NULL);
 201 }
 202
 203 /*
 204  * Free current thread data structures etc..
 205  */
 206 void exit_thread(void)
 207 {
 208 }
 209
 210 void flush_thread(void)
 211 {
 212         clear_used_math();
 213         clear_tsk_thread_flag(current, TIF_USEDFPU);
 214 }
 215
 216 void release_thread(struct task_struct *dead_task)
 217 {
 218 }
 219
 220 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
 221         unsigned long unused,
 222         struct task_struct * p, struct pt_regs * regs)
 223 {
 224         struct fake_frame
 225           {
 226             struct stack_frame sf;
 227             struct pt_regs childregs;
 228           } *frame;
 229
 230         frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
 231         p->thread.ksp = (unsigned long) frame;
 232         /* Store access registers to kernel stack of new process. */
 233         frame->childregs = *regs;
 234         frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
 235         frame->childregs.gprs[15] = new_stackp;
 236         frame->sf.back_chain = 0;
 237
 238         /* new return point is ret_from_fork */
 239         frame->sf.gprs[8] = (unsigned long) ret_from_fork;
 240
 241         /* fake return stack for resume(), don't go back to schedule */
 242         frame->sf.gprs[9] = (unsigned long) frame;
 243
 244         /* Save access registers to new thread structure. */
 245         save_access_regs(&p->thread.acrs[0]);
 246
 247 #ifndef CONFIG_64BIT
 248         /*
 249          * save fprs to current->thread.fp_regs to merge them with
 250          * the emulated registers and then copy the result to the child.
 251          */
 252         save_fp_regs(&current->thread.fp_regs);
 253         memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
 254                sizeof(s390_fp_regs));
 255         p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
 256         /* Set a new TLS ?  */
 257         if (clone_flags & CLONE_SETTLS)
 258                 p->thread.acrs[0] = regs->gprs[6];
 259 #else /* CONFIG_64BIT */
 260         /* Save the fpu registers to new thread structure. */
 261         save_fp_regs(&p->thread.fp_regs);
 262         p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
 263         /* Set a new TLS ?  */
 264         if (clone_flags & CLONE_SETTLS) {
 265                 if (test_thread_flag(TIF_31BIT)) {
 266                         p->thread.acrs[0] = (unsigned int) regs->gprs[6];
 267                 } else {
 268                         p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
 269                         p->thread.acrs[1] = (unsigned int) regs->gprs[6];
 270                 }
 271         }
 272 #endif /* CONFIG_64BIT */
 273         /* start new process with ar4 pointing to the correct address space */
 274         p->thread.mm_segment = get_fs();
 275         /* Don't copy debug registers */
 276         memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
 277
 278         return 0;
 279 }
 280
 281 asmlinkage long sys_fork(struct pt_regs regs)
 282 {
 283         return do_fork(SIGCHLD, regs.gprs[15], &regs, 0, NULL, NULL);
 284 }
 285
 286 asmlinkage long sys_clone(struct pt_regs regs)
 287 {
 288         unsigned long clone_flags;
 289         unsigned long newsp;
 290         int __user *parent_tidptr, *child_tidptr;
 291
 292         clone_flags = regs.gprs[3];
 293         newsp = regs.orig_gpr2;
 294         parent_tidptr = (int __user *) regs.gprs[4];
 295         child_tidptr = (int __user *) regs.gprs[5];
 296         if (!newsp)
 297                 newsp = regs.gprs[15];
 298         return do_fork(clone_flags, newsp, &regs, 0,
 299                        parent_tidptr, child_tidptr);
 300 }
 301
 302 /*
 303  * This is trivial, and on the face of it looks like it
 304  * could equally well be done in user mode.
 305  *
 306  * Not so, for quite unobvious reasons - register pressure.
 307  * In user mode vfork() cannot have a stack frame, and if
 308  * done by calling the "clone()" system call directly, you
 309  * do not have enough call-clobbered registers to hold all
 310  * the information you need.
 311  */
 312 asmlinkage long sys_vfork(struct pt_regs regs)
 313 {
 314         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
 315                        regs.gprs[15], &regs, 0, NULL, NULL);
 316 }
 317
 318 /*
 319  * sys_execve() executes a new program.
 320  */
 321 asmlinkage long sys_execve(struct pt_regs regs)
 322 {
 323         int error;
 324         char * filename;
 325
 326         filename = getname((char __user *) regs.orig_gpr2);
 327         error = PTR_ERR(filename);
 328         if (IS_ERR(filename))
 329                 goto out;
 330         error = do_execve(filename, (char __user * __user *) regs.gprs[3],
 331                           (char __user * __user *) regs.gprs[4], &regs);
 332         if (error == 0) {
 333                 task_lock(current);
 334                 current->ptrace &= ~PT_DTRACE;
 335                 task_unlock(current);
 336                 current->thread.fp_regs.fpc = 0;
 337                 if (MACHINE_HAS_IEEE)
 338                         asm volatile("sfpc %0,%0" : : "d" (0));
 339         }
 340         putname(filename);
 341 out:
 342         return error;
 343 }
 344
 345
 346 /*
 347  * fill in the FPU structure for a core dump.
 348  */
 349 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
 350 {
 351 #ifndef CONFIG_64BIT
 352         /*
 353          * save fprs to current->thread.fp_regs to merge them with
 354          * the emulated registers and then copy the result to the dump.
 355          */
 356         save_fp_regs(&current->thread.fp_regs);
 357         memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
 358 #else /* CONFIG_64BIT */
 359         save_fp_regs(fpregs);
 360 #endif /* CONFIG_64BIT */
 361         return 1;
 362 }
 363
 364 unsigned long get_wchan(struct task_struct *p)
 365 {
 366         struct stack_frame *sf, *low, *high;
 367         unsigned long return_address;
 368         int count;
 369
 370         if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
 371                 return 0;
 372         low = task_stack_page(p);
 373         high = (struct stack_frame *) task_pt_regs(p);
 374         sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
 375         if (sf <= low || sf > high)
 376                 return 0;
 377         for (count = 0; count < 16; count++) {
 378                 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
 379                 if (sf <= low || sf > high)
 380                         return 0;
 381                 return_address = sf->gprs[8] & PSW_ADDR_INSN;
 382                 if (!in_sched_functions(return_address))
 383                         return return_address;
 384         }
 385         return 0;
 386 }
 387