arch/m68k/kernel/process.c

   1 /*
   2  *  linux/arch/m68k/kernel/process.c
   3  *
   4  *  Copyright (C) 1995  Hamish Macdonald
   5  *
   6  *  68060 fixes by Jesper Skov
   7  */
   8
   9 /*
  10  * This file handles the architecture-dependent parts of process handling..
  11  */
  12
  13 #include <linux/errno.h>
  14 #include <linux/module.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mm.h>
  18 #include <linux/fs.h>
  19 #include <linux/smp.h>
  20 #include <linux/smp_lock.h>
  21 #include <linux/stddef.h>
  22 #include <linux/unistd.h>
  23 #include <linux/ptrace.h>
  24 #include <linux/slab.h>
  25 #include <linux/user.h>
  26 #include <linux/reboot.h>
  27 #include <linux/init_task.h>
  28 #include <linux/mqueue.h>
  29
  30 #include <asm/uaccess.h>
  31 #include <asm/system.h>
  32 #include <asm/traps.h>
  33 #include <asm/machdep.h>
  34 #include <asm/setup.h>
  35 #include <asm/pgtable.h>
  36
  37 /*
  38  * Initial task/thread structure. Make this a per-architecture thing,
  39  * because different architectures tend to have different
  40  * alignment requirements and potentially different initial
  41  * setup.
  42  */
  43 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
  44 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
  45 struct mm_struct init_mm = INIT_MM(init_mm);
  46
  47 EXPORT_SYMBOL(init_mm);
  48
  49 union thread_union init_thread_union
  50 __attribute__((section(".data.init_task"), aligned(THREAD_SIZE)))
  51        = { INIT_THREAD_INFO(init_task) };
  52
  53 /* initial task structure */
  54 struct task_struct init_task = INIT_TASK(init_task);
  55
  56 EXPORT_SYMBOL(init_task);
  57
  58 asmlinkage void ret_from_fork(void);
  59
  60
  61 /*
  62  * Return saved PC from a blocked thread
  63  */
  64 unsigned long thread_saved_pc(struct task_struct *tsk)
  65 {
  66         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  67         /* Check whether the thread is blocked in resume() */
  68         if (in_sched_functions(sw->retpc))
  69                 return ((unsigned long *)sw->a6)[1];
  70         else
  71                 return sw->retpc;
  72 }
  73
  74 /*
  75  * The idle loop on an m68k..
  76  */
  77 static void default_idle(void)
  78 {
  79         if (!need_resched())
  80 #if defined(MACH_ATARI_ONLY)
  81                 /* block out HSYNC on the atari (falcon) */
  82                 __asm__("stop #0x2200" : : : "cc");
  83 #else
  84                 __asm__("stop #0x2000" : : : "cc");
  85 #endif
  86 }
  87
  88 void (*idle)(void) = default_idle;
  89
  90 /*
  91  * The idle thread. There's no useful work to be
  92  * done, so just try to conserve power and have a
  93  * low exit latency (ie sit in a loop waiting for
  94  * somebody to say that they'd like to reschedule)
  95  */
  96 void cpu_idle(void)
  97 {
  98         /* endless idle loop with no priority at all */
  99         while (1) {
 100                 while (!need_resched())
 101                         idle();
 102                 preempt_enable_no_resched();
 103                 schedule();
 104                 preempt_disable();
 105         }
 106 }
 107
 108 void machine_restart(char * __unused)
 109 {
 110         if (mach_reset)
 111                 mach_reset();
 112         for (;;);
 113 }
 114
 115 void machine_halt(void)
 116 {
 117         if (mach_halt)
 118                 mach_halt();
 119         for (;;);
 120 }
 121
 122 void machine_power_off(void)
 123 {
 124         if (mach_power_off)
 125                 mach_power_off();
 126         for (;;);
 127 }
 128
 129 void (*pm_power_off)(void) = machine_power_off;
 130 EXPORT_SYMBOL(pm_power_off);
 131
 132 void show_regs(struct pt_regs * regs)
 133 {
 134         printk("\n");
 135         printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
 136                regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
 137         printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
 138                regs->orig_d0, regs->d0, regs->a2, regs->a1);
 139         printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
 140                regs->a0, regs->d5, regs->d4);
 141         printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
 142                regs->d3, regs->d2, regs->d1);
 143         if (!(regs->sr & PS_S))
 144                 printk("USP: %08lx\n", rdusp());
 145 }
 146
 147 /*
 148  * Create a kernel thread
 149  */
 150 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 151 {
 152         int pid;
 153         mm_segment_t fs;
 154
 155         fs = get_fs();
 156         set_fs (KERNEL_DS);
 157
 158         {
 159         register long retval __asm__ ("d0");
 160         register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
 161
 162         retval = __NR_clone;
 163         __asm__ __volatile__
 164           ("clrl %%d2\n\t"
 165            "trap #0\n\t"                /* Linux/m68k system call */
 166            "tstl %0\n\t"                /* child or parent */
 167            "jne 1f\n\t"                 /* parent - jump */
 168            "lea %%sp@(%c7),%6\n\t"      /* reload current */
 169            "movel %6@,%6\n\t"
 170            "movel %3,%%sp@-\n\t"        /* push argument */
 171            "jsr %4@\n\t"                /* call fn */
 172            "movel %0,%%d1\n\t"          /* pass exit value */
 173            "movel %2,%%d0\n\t"          /* exit */
 174            "trap #0\n"
 175            "1:"
 176            : "+d" (retval)
 177            : "i" (__NR_clone), "i" (__NR_exit),
 178              "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
 179              "i" (-THREAD_SIZE)
 180            : "d2");
 181
 182         pid = retval;
 183         }
 184
 185         set_fs (fs);
 186         return pid;
 187 }
 188 EXPORT_SYMBOL(kernel_thread);
 189
 190 void flush_thread(void)
 191 {
 192         unsigned long zero = 0;
 193         set_fs(USER_DS);
 194         current->thread.fs = __USER_DS;
 195         if (!FPU_IS_EMU)
 196                 asm volatile (".chip 68k/68881\n\t"
 197                               "frestore %0@\n\t"
 198                               ".chip 68k" : : "a" (&zero));
 199 }
 200
 201 /*
 202  * "m68k_fork()".. By the time we get here, the
 203  * non-volatile registers have also been saved on the
 204  * stack. We do some ugly pointer stuff here.. (see
 205  * also copy_thread)
 206  */
 207
 208 asmlinkage int m68k_fork(struct pt_regs *regs)
 209 {
 210         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 211 }
 212
 213 asmlinkage int m68k_vfork(struct pt_regs *regs)
 214 {
 215         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
 216                        NULL, NULL);
 217 }
 218
 219 asmlinkage int m68k_clone(struct pt_regs *regs)
 220 {
 221         unsigned long clone_flags;
 222         unsigned long newsp;
 223         int __user *parent_tidptr, *child_tidptr;
 224
 225         /* syscall2 puts clone_flags in d1 and usp in d2 */
 226         clone_flags = regs->d1;
 227         newsp = regs->d2;
 228         parent_tidptr = (int __user *)regs->d3;
 229         child_tidptr = (int __user *)regs->d4;
 230         if (!newsp)
 231                 newsp = rdusp();
 232         return do_fork(clone_flags, newsp, regs, 0,
 233                        parent_tidptr, child_tidptr);
 234 }
 235
 236 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 237                  unsigned long unused,
 238                  struct task_struct * p, struct pt_regs * regs)
 239 {
 240         struct pt_regs * childregs;
 241         struct switch_stack * childstack, *stack;
 242         unsigned long *retp;
 243
 244         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 245
 246         *childregs = *regs;
 247         childregs->d0 = 0;
 248
 249         retp = ((unsigned long *) regs);
 250         stack = ((struct switch_stack *) retp) - 1;
 251
 252         childstack = ((struct switch_stack *) childregs) - 1;
 253         *childstack = *stack;
 254         childstack->retpc = (unsigned long)ret_from_fork;
 255
 256         p->thread.usp = usp;
 257         p->thread.ksp = (unsigned long)childstack;
 258         /*
 259          * Must save the current SFC/DFC value, NOT the value when
 260          * the parent was last descheduled - RGH  10-08-96
 261          */
 262         p->thread.fs = get_fs().seg;
 263
 264         if (!FPU_IS_EMU) {
 265                 /* Copy the current fpu state */
 266                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 267
 268                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2])
 269                   asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 270                                 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 271                                 : : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
 272                                 : "memory");
 273                 /* Restore the state in case the fpu was busy */
 274                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 275         }
 276
 277         return 0;
 278 }
 279
 280 /* Fill in the fpu structure for a core dump.  */
 281
 282 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 283 {
 284         char fpustate[216];
 285
 286         if (FPU_IS_EMU) {
 287                 int i;
 288
 289                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 290                 memcpy(fpu->fpregs, current->thread.fp, 96);
 291                 /* Convert internal fpu reg representation
 292                  * into long double format
 293                  */
 294                 for (i = 0; i < 24; i += 3)
 295                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 296                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 297                 return 1;
 298         }
 299
 300         /* First dump the fpu context to avoid protocol violation.  */
 301         asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 302         if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 303                 return 0;
 304
 305         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 306                 :: "m" (fpu->fpcntl[0])
 307                 : "memory");
 308         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 309                 :: "m" (fpu->fpregs[0])
 310                 : "memory");
 311         return 1;
 312 }
 313 EXPORT_SYMBOL(dump_fpu);
 314
 315 /*
 316  * sys_execve() executes a new program.
 317  */
 318 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 319 {
 320         int error;
 321         char * filename;
 322         struct pt_regs *regs = (struct pt_regs *) &name;
 323
 324         lock_kernel();
 325         filename = getname(name);
 326         error = PTR_ERR(filename);
 327         if (IS_ERR(filename))
 328                 goto out;
 329         error = do_execve(filename, argv, envp, regs);
 330         putname(filename);
 331 out:
 332         unlock_kernel();
 333         return error;
 334 }
 335
 336 unsigned long get_wchan(struct task_struct *p)
 337 {
 338         unsigned long fp, pc;
 339         unsigned long stack_page;
 340         int count = 0;
 341         if (!p || p == current || p->state == TASK_RUNNING)
 342                 return 0;
 343
 344         stack_page = (unsigned long)task_stack_page(p);
 345         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 346         do {
 347                 if (fp < stack_page+sizeof(struct thread_info) ||
 348                     fp >= 8184+stack_page)
 349                         return 0;
 350                 pc = ((unsigned long *)fp)[1];
 351                 if (!in_sched_functions(pc))
 352                         return pc;
 353                 fp = *(unsigned long *) fp;
 354         } while (count++ < 16);
 355         return 0;
 356 }