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