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/config.h>
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mm.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 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                 schedule();
 106         }
 107 }
 108
 109 void machine_restart(char * __unused)
 110 {
 111         if (mach_reset)
 112                 mach_reset();
 113         for (;;);
 114 }
 115
 116 void machine_halt(void)
 117 {
 118         if (mach_halt)
 119                 mach_halt();
 120         for (;;);
 121 }
 122
 123 void machine_power_off(void)
 124 {
 125         if (mach_power_off)
 126                 mach_power_off();
 127         for (;;);
 128 }
 129
 130 void show_regs(struct pt_regs * regs)
 131 {
 132         printk("\n");
 133         printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
 134                regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
 135         printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
 136                regs->orig_d0, regs->d0, regs->a2, regs->a1);
 137         printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
 138                regs->a0, regs->d5, regs->d4);
 139         printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
 140                regs->d3, regs->d2, regs->d1);
 141         if (!(regs->sr & PS_S))
 142                 printk("USP: %08lx\n", rdusp());
 143 }
 144
 145 /*
 146  * Create a kernel thread
 147  */
 148 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 149 {
 150         int pid;
 151         mm_segment_t fs;
 152
 153         fs = get_fs();
 154         set_fs (KERNEL_DS);
 155
 156         {
 157         register long retval __asm__ ("d0");
 158         register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
 159
 160         retval = __NR_clone;
 161         __asm__ __volatile__
 162           ("clrl %%d2\n\t"
 163            "trap #0\n\t"                /* Linux/m68k system call */
 164            "tstl %0\n\t"                /* child or parent */
 165            "jne 1f\n\t"                 /* parent - jump */
 166            "lea %%sp@(%c7),%6\n\t"      /* reload current */
 167            "movel %6@,%6\n\t"
 168            "movel %3,%%sp@-\n\t"        /* push argument */
 169            "jsr %4@\n\t"                /* call fn */
 170            "movel %0,%%d1\n\t"          /* pass exit value */
 171            "movel %2,%%d0\n\t"          /* exit */
 172            "trap #0\n"
 173            "1:"
 174            : "+d" (retval)
 175            : "i" (__NR_clone), "i" (__NR_exit),
 176              "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
 177              "i" (-THREAD_SIZE)
 178            : "d2");
 179
 180         pid = retval;
 181         }
 182
 183         set_fs (fs);
 184         return pid;
 185 }
 186
 187 void flush_thread(void)
 188 {
 189         unsigned long zero = 0;
 190         set_fs(USER_DS);
 191         current->thread.fs = __USER_DS;
 192         if (!FPU_IS_EMU)
 193                 asm volatile (".chip 68k/68881\n\t"
 194                               "frestore %0@\n\t"
 195                               ".chip 68k" : : "a" (&zero));
 196 }
 197
 198 /*
 199  * "m68k_fork()".. By the time we get here, the
 200  * non-volatile registers have also been saved on the
 201  * stack. We do some ugly pointer stuff here.. (see
 202  * also copy_thread)
 203  */
 204
 205 asmlinkage int m68k_fork(struct pt_regs *regs)
 206 {
 207         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 208 }
 209
 210 asmlinkage int m68k_vfork(struct pt_regs *regs)
 211 {
 212         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
 213                        NULL, NULL);
 214 }
 215
 216 asmlinkage int m68k_clone(struct pt_regs *regs)
 217 {
 218         unsigned long clone_flags;
 219         unsigned long newsp;
 220         int *parent_tidptr, *child_tidptr;
 221
 222         /* syscall2 puts clone_flags in d1 and usp in d2 */
 223         clone_flags = regs->d1;
 224         newsp = regs->d2;
 225         parent_tidptr = (int *)regs->d3;
 226         child_tidptr = (int *)regs->d4;
 227         if (!newsp)
 228                 newsp = rdusp();
 229         return do_fork(clone_flags, newsp, regs, 0,
 230                        parent_tidptr, child_tidptr);
 231 }
 232
 233 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 234                  unsigned long unused,
 235                  struct task_struct * p, struct pt_regs * regs)
 236 {
 237         struct pt_regs * childregs;
 238         struct switch_stack * childstack, *stack;
 239         unsigned long stack_offset, *retp;
 240
 241         stack_offset = THREAD_SIZE - sizeof(struct pt_regs);
 242         childregs = (struct pt_regs *) ((unsigned long) (p->thread_info) + stack_offset);
 243
 244         *childregs = *regs;
 245         childregs->d0 = 0;
 246
 247         retp = ((unsigned long *) regs);
 248         stack = ((struct switch_stack *) retp) - 1;
 249
 250         childstack = ((struct switch_stack *) childregs) - 1;
 251         *childstack = *stack;
 252         childstack->retpc = (unsigned long)ret_from_fork;
 253
 254         p->thread.usp = usp;
 255         p->thread.ksp = (unsigned long)childstack;
 256         /*
 257          * Must save the current SFC/DFC value, NOT the value when
 258          * the parent was last descheduled - RGH  10-08-96
 259          */
 260         p->thread.fs = get_fs().seg;
 261
 262         if (!FPU_IS_EMU) {
 263                 /* Copy the current fpu state */
 264                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 265
 266                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2])
 267                   asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 268                                 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 269                                 : : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
 270                                 : "memory");
 271                 /* Restore the state in case the fpu was busy */
 272                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 273         }
 274
 275         return 0;
 276 }
 277
 278 /* Fill in the fpu structure for a core dump.  */
 279
 280 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 281 {
 282         char fpustate[216];
 283
 284         if (FPU_IS_EMU) {
 285                 int i;
 286
 287                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 288                 memcpy(fpu->fpregs, current->thread.fp, 96);
 289                 /* Convert internal fpu reg representation
 290                  * into long double format
 291                  */
 292                 for (i = 0; i < 24; i += 3)
 293                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 294                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 295                 return 1;
 296         }
 297
 298         /* First dump the fpu context to avoid protocol violation.  */
 299         asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 300         if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 301                 return 0;
 302
 303         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 304                 :: "m" (fpu->fpcntl[0])
 305                 : "memory");
 306         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 307                 :: "m" (fpu->fpregs[0])
 308                 : "memory");
 309         return 1;
 310 }
 311
 312 /*
 313  * fill in the user structure for a core dump..
 314  */
 315 void dump_thread(struct pt_regs * regs, struct user * dump)
 316 {
 317         struct switch_stack *sw;
 318
 319 /* changed the size calculations - should hopefully work better. lbt */
 320         dump->magic = CMAGIC;
 321         dump->start_code = 0;
 322         dump->start_stack = rdusp() & ~(PAGE_SIZE - 1);
 323         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
 324         dump->u_dsize = ((unsigned long) (current->mm->brk +
 325                                           (PAGE_SIZE-1))) >> PAGE_SHIFT;
 326         dump->u_dsize -= dump->u_tsize;
 327         dump->u_ssize = 0;
 328
 329         if (dump->start_stack < TASK_SIZE)
 330                 dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
 331
 332         dump->u_ar0 = (struct user_regs_struct *)((int)&dump->regs - (int)dump);
 333         sw = ((struct switch_stack *)regs) - 1;
 334         dump->regs.d1 = regs->d1;
 335         dump->regs.d2 = regs->d2;
 336         dump->regs.d3 = regs->d3;
 337         dump->regs.d4 = regs->d4;
 338         dump->regs.d5 = regs->d5;
 339         dump->regs.d6 = sw->d6;
 340         dump->regs.d7 = sw->d7;
 341         dump->regs.a0 = regs->a0;
 342         dump->regs.a1 = regs->a1;
 343         dump->regs.a2 = regs->a2;
 344         dump->regs.a3 = sw->a3;
 345         dump->regs.a4 = sw->a4;
 346         dump->regs.a5 = sw->a5;
 347         dump->regs.a6 = sw->a6;
 348         dump->regs.d0 = regs->d0;
 349         dump->regs.orig_d0 = regs->orig_d0;
 350         dump->regs.stkadj = regs->stkadj;
 351         dump->regs.sr = regs->sr;
 352         dump->regs.pc = regs->pc;
 353         dump->regs.fmtvec = (regs->format << 12) | regs->vector;
 354         /* dump floating point stuff */
 355         dump->u_fpvalid = dump_fpu (regs, &dump->m68kfp);
 356 }
 357
 358 /*
 359  * sys_execve() executes a new program.
 360  */
 361 asmlinkage int sys_execve(char *name, char **argv, char **envp)
 362 {
 363         int error;
 364         char * filename;
 365         struct pt_regs *regs = (struct pt_regs *) &name;
 366
 367         lock_kernel();
 368         filename = getname(name);
 369         error = PTR_ERR(filename);
 370         if (IS_ERR(filename))
 371                 goto out;
 372         error = do_execve(filename, argv, envp, regs);
 373         putname(filename);
 374 out:
 375         unlock_kernel();
 376         return error;
 377 }
 378
 379 unsigned long get_wchan(struct task_struct *p)
 380 {
 381         unsigned long fp, pc;
 382         unsigned long stack_page;
 383         int count = 0;
 384         if (!p || p == current || p->state == TASK_RUNNING)
 385                 return 0;
 386
 387         stack_page = (unsigned long)(p->thread_info);
 388         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 389         do {
 390                 if (fp < stack_page+sizeof(struct thread_info) ||
 391                     fp >= 8184+stack_page)
 392                         return 0;
 393                 pc = ((unsigned long *)fp)[1];
 394                 if (!in_sched_functions(pc))
 395                         return pc;
 396                 fp = *(unsigned long *) fp;
 397         } while (count++ < 16);
 398         return 0;
 399 }