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