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/a.out.h>
  27 #include <linux/reboot.h>
  28 #include <linux/init_task.h>
  29 #include <linux/mqueue.h>
  30
  31 #include <asm/uaccess.h>
  32 #include <asm/system.h>
  33 #include <asm/traps.h>
  34 #include <asm/machdep.h>
  35 #include <asm/setup.h>
  36 #include <asm/pgtable.h>
  37
  38 /*
  39  * Initial task/thread structure. Make this a per-architecture thing,
  40  * because different architectures tend to have different
  41  * alignment requirements and potentially different initial
  42  * setup.
  43  */
  44 static struct fs_struct init_fs = INIT_FS;
  45 static struct files_struct init_files = INIT_FILES;
  46 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
  47 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
  48 struct mm_struct init_mm = INIT_MM(init_mm);
  49
  50 EXPORT_SYMBOL(init_mm);
  51
  52 union thread_union init_thread_union
  53 __attribute__((section(".data.init_task"), aligned(THREAD_SIZE)))
  54        = { INIT_THREAD_INFO(init_task) };
  55
  56 /* initial task structure */
  57 struct task_struct init_task = INIT_TASK(init_task);
  58
  59 EXPORT_SYMBOL(init_task);
  60
  61 asmlinkage void ret_from_fork(void);
  62
  63
  64 /*
  65  * Return saved PC from a blocked thread
  66  */
  67 unsigned long thread_saved_pc(struct task_struct *tsk)
  68 {
  69         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  70         /* Check whether the thread is blocked in resume() */
  71         if (in_sched_functions(sw->retpc))
  72                 return ((unsigned long *)sw->a6)[1];
  73         else
  74                 return sw->retpc;
  75 }
  76
  77 /*
  78  * The idle loop on an m68k..
  79  */
  80 static void default_idle(void)
  81 {
  82         if (!need_resched())
  83 #if defined(MACH_ATARI_ONLY) && !defined(CONFIG_HADES)
  84                 /* block out HSYNC on the atari (falcon) */
  85                 __asm__("stop #0x2200" : : : "cc");
  86 #else
  87                 __asm__("stop #0x2000" : : : "cc");
  88 #endif
  89 }
  90
  91 void (*idle)(void) = default_idle;
  92
  93 /*
  94  * The idle thread. There's no useful work to be
  95  * done, so just try to conserve power and have a
  96  * low exit latency (ie sit in a loop waiting for
  97  * somebody to say that they'd like to reschedule)
  98  */
  99 void cpu_idle(void)
 100 {
 101         /* endless idle loop with no priority at all */
 102         while (1) {
 103                 while (!need_resched())
 104                         idle();
 105                 preempt_enable_no_resched();
 106                 schedule();
 107                 preempt_disable();
 108         }
 109 }
 110
 111 void machine_restart(char * __unused)
 112 {
 113         if (mach_reset)
 114                 mach_reset();
 115         for (;;);
 116 }
 117
 118 void machine_halt(void)
 119 {
 120         if (mach_halt)
 121                 mach_halt();
 122         for (;;);
 123 }
 124
 125 void machine_power_off(void)
 126 {
 127         if (mach_power_off)
 128                 mach_power_off();
 129         for (;;);
 130 }
 131
 132 void (*pm_power_off)(void) = machine_power_off;
 133 EXPORT_SYMBOL(pm_power_off);
 134
 135 void show_regs(struct pt_regs * regs)
 136 {
 137         printk("\n");
 138         printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
 139                regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
 140         printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
 141                regs->orig_d0, regs->d0, regs->a2, regs->a1);
 142         printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
 143                regs->a0, regs->d5, regs->d4);
 144         printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
 145                regs->d3, regs->d2, regs->d1);
 146         if (!(regs->sr & PS_S))
 147                 printk("USP: %08lx\n", rdusp());
 148 }
 149
 150 /*
 151  * Create a kernel thread
 152  */
 153 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 154 {
 155         int pid;
 156         mm_segment_t fs;
 157
 158         fs = get_fs();
 159         set_fs (KERNEL_DS);
 160
 161         {
 162         register long retval __asm__ ("d0");
 163         register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
 164
 165         retval = __NR_clone;
 166         __asm__ __volatile__
 167           ("clrl %%d2\n\t"
 168            "trap #0\n\t"                /* Linux/m68k system call */
 169            "tstl %0\n\t"                /* child or parent */
 170            "jne 1f\n\t"                 /* parent - jump */
 171            "lea %%sp@(%c7),%6\n\t"      /* reload current */
 172            "movel %6@,%6\n\t"
 173            "movel %3,%%sp@-\n\t"        /* push argument */
 174            "jsr %4@\n\t"                /* call fn */
 175            "movel %0,%%d1\n\t"          /* pass exit value */
 176            "movel %2,%%d0\n\t"          /* exit */
 177            "trap #0\n"
 178            "1:"
 179            : "+d" (retval)
 180            : "i" (__NR_clone), "i" (__NR_exit),
 181              "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
 182              "i" (-THREAD_SIZE)
 183            : "d2");
 184
 185         pid = retval;
 186         }
 187
 188         set_fs (fs);
 189         return pid;
 190 }
 191 EXPORT_SYMBOL(kernel_thread);
 192
 193 void flush_thread(void)
 194 {
 195         unsigned long zero = 0;
 196         set_fs(USER_DS);
 197         current->thread.fs = __USER_DS;
 198         if (!FPU_IS_EMU)
 199                 asm volatile (".chip 68k/68881\n\t"
 200                               "frestore %0@\n\t"
 201                               ".chip 68k" : : "a" (&zero));
 202 }
 203
 204 /*
 205  * "m68k_fork()".. By the time we get here, the
 206  * non-volatile registers have also been saved on the
 207  * stack. We do some ugly pointer stuff here.. (see
 208  * also copy_thread)
 209  */
 210
 211 asmlinkage int m68k_fork(struct pt_regs *regs)
 212 {
 213         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 214 }
 215
 216 asmlinkage int m68k_vfork(struct pt_regs *regs)
 217 {
 218         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
 219                        NULL, NULL);
 220 }
 221
 222 asmlinkage int m68k_clone(struct pt_regs *regs)
 223 {
 224         unsigned long clone_flags;
 225         unsigned long newsp;
 226         int __user *parent_tidptr, *child_tidptr;
 227
 228         /* syscall2 puts clone_flags in d1 and usp in d2 */
 229         clone_flags = regs->d1;
 230         newsp = regs->d2;
 231         parent_tidptr = (int __user *)regs->d3;
 232         child_tidptr = (int __user *)regs->d4;
 233         if (!newsp)
 234                 newsp = rdusp();
 235         return do_fork(clone_flags, newsp, regs, 0,
 236                        parent_tidptr, child_tidptr);
 237 }
 238
 239 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 240                  unsigned long unused,
 241                  struct task_struct * p, struct pt_regs * regs)
 242 {
 243         struct pt_regs * childregs;
 244         struct switch_stack * childstack, *stack;
 245         unsigned long *retp;
 246
 247         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 248
 249         *childregs = *regs;
 250         childregs->d0 = 0;
 251
 252         retp = ((unsigned long *) regs);
 253         stack = ((struct switch_stack *) retp) - 1;
 254
 255         childstack = ((struct switch_stack *) childregs) - 1;
 256         *childstack = *stack;
 257         childstack->retpc = (unsigned long)ret_from_fork;
 258
 259         p->thread.usp = usp;
 260         p->thread.ksp = (unsigned long)childstack;
 261         /*
 262          * Must save the current SFC/DFC value, NOT the value when
 263          * the parent was last descheduled - RGH  10-08-96
 264          */
 265         p->thread.fs = get_fs().seg;
 266
 267         if (!FPU_IS_EMU) {
 268                 /* Copy the current fpu state */
 269                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 270
 271                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2])
 272                   asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 273                                 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 274                                 : : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
 275                                 : "memory");
 276                 /* Restore the state in case the fpu was busy */
 277                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 278         }
 279
 280         return 0;
 281 }
 282
 283 /* Fill in the fpu structure for a core dump.  */
 284
 285 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 286 {
 287         char fpustate[216];
 288
 289         if (FPU_IS_EMU) {
 290                 int i;
 291
 292                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 293                 memcpy(fpu->fpregs, current->thread.fp, 96);
 294                 /* Convert internal fpu reg representation
 295                  * into long double format
 296                  */
 297                 for (i = 0; i < 24; i += 3)
 298                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 299                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 300                 return 1;
 301         }
 302
 303         /* First dump the fpu context to avoid protocol violation.  */
 304         asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 305         if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 306                 return 0;
 307
 308         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 309                 :: "m" (fpu->fpcntl[0])
 310                 : "memory");
 311         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 312                 :: "m" (fpu->fpregs[0])
 313                 : "memory");
 314         return 1;
 315 }
 316 EXPORT_SYMBOL(dump_fpu);
 317
 318 /*
 319  * sys_execve() executes a new program.
 320  */
 321 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 322 {
 323         int error;
 324         char * filename;
 325         struct pt_regs *regs = (struct pt_regs *) &name;
 326
 327         lock_kernel();
 328         filename = getname(name);
 329         error = PTR_ERR(filename);
 330         if (IS_ERR(filename))
 331                 goto out;
 332         error = do_execve(filename, argv, envp, regs);
 333         putname(filename);
 334 out:
 335         unlock_kernel();
 336         return error;
 337 }
 338
 339 unsigned long get_wchan(struct task_struct *p)
 340 {
 341         unsigned long fp, pc;
 342         unsigned long stack_page;
 343         int count = 0;
 344         if (!p || p == current || p->state == TASK_RUNNING)
 345                 return 0;
 346
 347         stack_page = (unsigned long)task_stack_page(p);
 348         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 349         do {
 350                 if (fp < stack_page+sizeof(struct thread_info) ||
 351                     fp >= 8184+stack_page)
 352                         return 0;
 353                 pc = ((unsigned long *)fp)[1];
 354                 if (!in_sched_functions(pc))
 355                         return pc;
 356                 fp = *(unsigned long *) fp;
 357         } while (count++ < 16);
 358         return 0;
 359 }