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 fs_struct init_fs = INIT_FS;
  44 static struct files_struct init_files = INIT_FILES;
  45 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
  46 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
  47 struct mm_struct init_mm = INIT_MM(init_mm);
  48
  49 EXPORT_SYMBOL(init_mm);
  50
  51 union thread_union init_thread_union
  52 __attribute__((section(".data.init_task"), aligned(THREAD_SIZE)))
  53        = { INIT_THREAD_INFO(init_task) };
  54
  55 /* initial task structure */
  56 struct task_struct init_task = INIT_TASK(init_task);
  57
  58 EXPORT_SYMBOL(init_task);
  59
  60 asmlinkage void ret_from_fork(void);
  61
  62
  63 /*
  64  * Return saved PC from a blocked thread
  65  */
  66 unsigned long thread_saved_pc(struct task_struct *tsk)
  67 {
  68         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  69         /* Check whether the thread is blocked in resume() */
  70         if (in_sched_functions(sw->retpc))
  71                 return ((unsigned long *)sw->a6)[1];
  72         else
  73                 return sw->retpc;
  74 }
  75
  76 /*
  77  * The idle loop on an m68k..
  78  */
  79 static void default_idle(void)
  80 {
  81         if (!need_resched())
  82 #if defined(MACH_ATARI_ONLY) && !defined(CONFIG_HADES)
  83                 /* block out HSYNC on the atari (falcon) */
  84                 __asm__("stop #0x2200" : : : "cc");
  85 #else
  86                 __asm__("stop #0x2000" : : : "cc");
  87 #endif
  88 }
  89
  90 void (*idle)(void) = default_idle;
  91
  92 /*
  93  * The idle thread. There's no useful work to be
  94  * done, so just try to conserve power and have a
  95  * low exit latency (ie sit in a loop waiting for
  96  * somebody to say that they'd like to reschedule)
  97  */
  98 void cpu_idle(void)
  99 {
 100         /* endless idle loop with no priority at all */
 101         while (1) {
 102                 while (!need_resched())
 103                         idle();
 104                 preempt_enable_no_resched();
 105                 schedule();
 106                 preempt_disable();
 107         }
 108 }
 109
 110 void machine_restart(char * __unused)
 111 {
 112         if (mach_reset)
 113                 mach_reset();
 114         for (;;);
 115 }
 116
 117 void machine_halt(void)
 118 {
 119         if (mach_halt)
 120                 mach_halt();
 121         for (;;);
 122 }
 123
 124 void machine_power_off(void)
 125 {
 126         if (mach_power_off)
 127                 mach_power_off();
 128         for (;;);
 129 }
 130
 131 void (*pm_power_off)(void) = machine_power_off;
 132 EXPORT_SYMBOL(pm_power_off);
 133
 134 void show_regs(struct pt_regs * regs)
 135 {
 136         printk("\n");
 137         printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
 138                regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
 139         printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
 140                regs->orig_d0, regs->d0, regs->a2, regs->a1);
 141         printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
 142                regs->a0, regs->d5, regs->d4);
 143         printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
 144                regs->d3, regs->d2, regs->d1);
 145         if (!(regs->sr & PS_S))
 146                 printk("USP: %08lx\n", rdusp());
 147 }
 148
 149 /*
 150  * Create a kernel thread
 151  */
 152 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 153 {
 154         int pid;
 155         mm_segment_t fs;
 156
 157         fs = get_fs();
 158         set_fs (KERNEL_DS);
 159
 160         {
 161         register long retval __asm__ ("d0");
 162         register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
 163
 164         retval = __NR_clone;
 165         __asm__ __volatile__
 166           ("clrl %%d2\n\t"
 167            "trap #0\n\t"                /* Linux/m68k system call */
 168            "tstl %0\n\t"                /* child or parent */
 169            "jne 1f\n\t"                 /* parent - jump */
 170            "lea %%sp@(%c7),%6\n\t"      /* reload current */
 171            "movel %6@,%6\n\t"
 172            "movel %3,%%sp@-\n\t"        /* push argument */
 173            "jsr %4@\n\t"                /* call fn */
 174            "movel %0,%%d1\n\t"          /* pass exit value */
 175            "movel %2,%%d0\n\t"          /* exit */
 176            "trap #0\n"
 177            "1:"
 178            : "+d" (retval)
 179            : "i" (__NR_clone), "i" (__NR_exit),
 180              "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
 181              "i" (-THREAD_SIZE)
 182            : "d2");
 183
 184         pid = retval;
 185         }
 186
 187         set_fs (fs);
 188         return pid;
 189 }
 190 EXPORT_SYMBOL(kernel_thread);
 191
 192 void flush_thread(void)
 193 {
 194         unsigned long zero = 0;
 195         set_fs(USER_DS);
 196         current->thread.fs = __USER_DS;
 197         if (!FPU_IS_EMU)
 198                 asm volatile (".chip 68k/68881\n\t"
 199                               "frestore %0@\n\t"
 200                               ".chip 68k" : : "a" (&zero));
 201 }
 202
 203 /*
 204  * "m68k_fork()".. By the time we get here, the
 205  * non-volatile registers have also been saved on the
 206  * stack. We do some ugly pointer stuff here.. (see
 207  * also copy_thread)
 208  */
 209
 210 asmlinkage int m68k_fork(struct pt_regs *regs)
 211 {
 212         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 213 }
 214
 215 asmlinkage int m68k_vfork(struct pt_regs *regs)
 216 {
 217         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
 218                        NULL, NULL);
 219 }
 220
 221 asmlinkage int m68k_clone(struct pt_regs *regs)
 222 {
 223         unsigned long clone_flags;
 224         unsigned long newsp;
 225         int __user *parent_tidptr, *child_tidptr;
 226
 227         /* syscall2 puts clone_flags in d1 and usp in d2 */
 228         clone_flags = regs->d1;
 229         newsp = regs->d2;
 230         parent_tidptr = (int __user *)regs->d3;
 231         child_tidptr = (int __user *)regs->d4;
 232         if (!newsp)
 233                 newsp = rdusp();
 234         return do_fork(clone_flags, newsp, regs, 0,
 235                        parent_tidptr, child_tidptr);
 236 }
 237
 238 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 239                  unsigned long unused,
 240                  struct task_struct * p, struct pt_regs * regs)
 241 {
 242         struct pt_regs * childregs;
 243         struct switch_stack * childstack, *stack;
 244         unsigned long *retp;
 245
 246         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 247
 248         *childregs = *regs;
 249         childregs->d0 = 0;
 250
 251         retp = ((unsigned long *) regs);
 252         stack = ((struct switch_stack *) retp) - 1;
 253
 254         childstack = ((struct switch_stack *) childregs) - 1;
 255         *childstack = *stack;
 256         childstack->retpc = (unsigned long)ret_from_fork;
 257
 258         p->thread.usp = usp;
 259         p->thread.ksp = (unsigned long)childstack;
 260         /*
 261          * Must save the current SFC/DFC value, NOT the value when
 262          * the parent was last descheduled - RGH  10-08-96
 263          */
 264         p->thread.fs = get_fs().seg;
 265
 266         if (!FPU_IS_EMU) {
 267                 /* Copy the current fpu state */
 268                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 269
 270                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2])
 271                   asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 272                                 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 273                                 : : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
 274                                 : "memory");
 275                 /* Restore the state in case the fpu was busy */
 276                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 277         }
 278
 279         return 0;
 280 }
 281
 282 /* Fill in the fpu structure for a core dump.  */
 283
 284 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 285 {
 286         char fpustate[216];
 287
 288         if (FPU_IS_EMU) {
 289                 int i;
 290
 291                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 292                 memcpy(fpu->fpregs, current->thread.fp, 96);
 293                 /* Convert internal fpu reg representation
 294                  * into long double format
 295                  */
 296                 for (i = 0; i < 24; i += 3)
 297                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 298                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 299                 return 1;
 300         }
 301
 302         /* First dump the fpu context to avoid protocol violation.  */
 303         asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 304         if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 305                 return 0;
 306
 307         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 308                 :: "m" (fpu->fpcntl[0])
 309                 : "memory");
 310         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 311                 :: "m" (fpu->fpregs[0])
 312                 : "memory");
 313         return 1;
 314 }
 315 EXPORT_SYMBOL(dump_fpu);
 316
 317 /*
 318  * sys_execve() executes a new program.
 319  */
 320 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 321 {
 322         int error;
 323         char * filename;
 324         struct pt_regs *regs = (struct pt_regs *) &name;
 325
 326         lock_kernel();
 327         filename = getname(name);
 328         error = PTR_ERR(filename);
 329         if (IS_ERR(filename))
 330                 goto out;
 331         error = do_execve(filename, argv, envp, regs);
 332         putname(filename);
 333 out:
 334         unlock_kernel();
 335         return error;
 336 }
 337
 338 unsigned long get_wchan(struct task_struct *p)
 339 {
 340         unsigned long fp, pc;
 341         unsigned long stack_page;
 342         int count = 0;
 343         if (!p || p == current || p->state == TASK_RUNNING)
 344                 return 0;
 345
 346         stack_page = (unsigned long)task_stack_page(p);
 347         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 348         do {
 349                 if (fp < stack_page+sizeof(struct thread_info) ||
 350                     fp >= 8184+stack_page)
 351                         return 0;
 352                 pc = ((unsigned long *)fp)[1];
 353                 if (!in_sched_functions(pc))
 354                         return pc;
 355                 fp = *(unsigned long *) fp;
 356         } while (count++ < 16);
 357         return 0;
 358 }