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/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mm.h>
  18 #include <linux/smp.h>
  19 #include <linux/smp_lock.h>
  20 #include <linux/stddef.h>
  21 #include <linux/unistd.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/malloc.h>
  24 #include <linux/user.h>
  25 #include <linux/a.out.h>
  26 #include <linux/reboot.h>
  27
  28 #include <asm/uaccess.h>
  29 #include <asm/system.h>
  30 #include <asm/traps.h>
  31 #include <asm/machdep.h>
  32 #include <asm/setup.h>
  33 #include <asm/pgtable.h>
  34
  35 /*
  36  * Initial task structure. Make this a per-architecture thing,
  37  * because different architectures tend to have different
  38  * alignment requirements and potentially different initial
  39  * setup.
  40  */
  41 static struct vm_area_struct init_mmap = INIT_MMAP;
  42 static struct fs_struct init_fs = INIT_FS;
  43 static struct file * init_fd_array[NR_OPEN] = { NULL, };
  44 static struct files_struct init_files = INIT_FILES;
  45 static struct signal_struct init_signals = INIT_SIGNALS;
  46 struct mm_struct init_mm = INIT_MM(init_mm);
  47
  48 union task_union init_task_union
  49         __attribute__((section("init_task"), aligned(2*PAGE_SIZE)))
  50         = { task: INIT_TASK };
  51
  52 asmlinkage void ret_from_exception(void);
  53
  54 /*
  55  * The idle loop on an m68k..
  56  */
  57 asmlinkage int sys_idle(void)
  58 {
  59         if (current->pid != 0)
  60                 return -EPERM;
  61
  62         /* endless idle loop with no priority at all */
  63         current->priority = 0;
  64         current->counter = -100;
  65         for (;;) {
  66                 if (!current->need_resched)
  67 #if defined(CONFIG_ATARI) && !defined(CONFIG_AMIGA) && !defined(CONFIG_MAC)
  68                         /* block out HSYNC on the atari (falcon) */
  69                         __asm__("stop #0x2200" : : : "cc");
  70 #else /* portable version */
  71                         __asm__("stop #0x2000" : : : "cc");
  72 #endif /* machine compilation types */
  73                 schedule();
  74                 check_pgt_cache();
  75         }
  76 }
  77
  78 void machine_restart(char * __unused)
  79 {
  80         if (mach_reset)
  81                 mach_reset();
  82 }
  83
  84 void machine_halt(void)
  85 {
  86 }
  87
  88 void machine_power_off(void)
  89 {
  90 #if defined(CONFIG_APM) && defined(CONFIG_APM_POWER_OFF)
  91         apm_set_power_state(APM_STATE_OFF);
  92 #endif
  93 }
  94
  95 void show_regs(struct pt_regs * regs)
  96 {
  97         printk("\n");
  98         printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x\n",
  99                regs->format, regs->vector, regs->pc, regs->sr);
 100         printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
 101                regs->orig_d0, regs->d0, regs->a2, regs->a1);
 102         printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
 103                regs->a0, regs->d5, regs->d4);
 104         printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
 105                regs->d3, regs->d2, regs->d1);
 106         if (!(regs->sr & PS_S))
 107                 printk("USP: %08lx\n", rdusp());
 108 }
 109
 110 /*
 111  * Create a kernel thread
 112  */
 113 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 114 {
 115         int pid;
 116         mm_segment_t fs;
 117
 118         fs = get_fs();
 119         set_fs (KERNEL_DS);
 120
 121         {
 122         register long retval __asm__ ("d0");
 123         register long clone_arg __asm__ ("d1") = flags | CLONE_VM;
 124
 125         __asm__ __volatile__
 126           ("clrl %%d2\n\t"
 127            "trap #0\n\t"                /* Linux/m68k system call */
 128            "tstl %0\n\t"                /* child or parent */
 129            "jne 1f\n\t"                 /* parent - jump */
 130            "lea %%sp@(-8192),%6\n\t"    /* reload current */
 131            "movel %3,%%sp@-\n\t"        /* push argument */
 132            "jsr %4@\n\t"                /* call fn */
 133            "movel %0,%%d1\n\t"          /* pass exit value */
 134            "movel %2,%0\n\t"            /* exit */
 135            "trap #0\n"
 136            "1:"
 137            : "=d" (retval)
 138            : "0" (__NR_clone), "i" (__NR_exit),
 139              "r" (arg), "a" (fn), "d" (clone_arg), "r" (current)
 140            : "d0", "d2");
 141         pid = retval;
 142         }
 143
 144         set_fs (fs);
 145         return pid;
 146 }
 147
 148 void flush_thread(void)
 149 {
 150         unsigned long zero = 0;
 151         set_fs(USER_DS);
 152         current->tss.fs = __USER_DS;
 153         asm volatile (".chip 68k/68881\n\t"
 154                       "frestore %0@\n\t"
 155                       ".chip 68k" : : "a" (&zero));
 156 }
 157
 158 /*
 159  * "m68k_fork()".. By the time we get here, the
 160  * non-volatile registers have also been saved on the
 161  * stack. We do some ugly pointer stuff here.. (see
 162  * also copy_thread)
 163  */
 164
 165 asmlinkage int m68k_fork(struct pt_regs *regs)
 166 {
 167         return do_fork(SIGCHLD, rdusp(), regs);
 168 }
 169
 170 asmlinkage int m68k_vfork(struct pt_regs *regs)
 171 {
 172         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs);
 173 }
 174
 175 asmlinkage int m68k_clone(struct pt_regs *regs)
 176 {
 177         unsigned long clone_flags;
 178         unsigned long newsp;
 179
 180         /* syscall2 puts clone_flags in d1 and usp in d2 */
 181         clone_flags = regs->d1;
 182         newsp = regs->d2;
 183         if (!newsp)
 184                 newsp = rdusp();
 185         return do_fork(clone_flags, newsp, regs);
 186 }
 187
 188 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 189                  struct task_struct * p, struct pt_regs * regs)
 190 {
 191         struct pt_regs * childregs;
 192         struct switch_stack * childstack, *stack;
 193         unsigned long stack_offset, *retp;
 194
 195         stack_offset = 2*PAGE_SIZE - sizeof(struct pt_regs);
 196         childregs = (struct pt_regs *) ((unsigned long) p + stack_offset);
 197
 198         *childregs = *regs;
 199         childregs->d0 = 0;
 200
 201         retp = ((unsigned long *) regs);
 202         stack = ((struct switch_stack *) retp) - 1;
 203
 204         childstack = ((struct switch_stack *) childregs) - 1;
 205         *childstack = *stack;
 206         childstack->retpc = (unsigned long) ret_from_exception;
 207
 208         p->tss.usp = usp;
 209         p->tss.ksp = (unsigned long)childstack;
 210         /*
 211          * Must save the current SFC/DFC value, NOT the value when
 212          * the parent was last descheduled - RGH  10-08-96
 213          */
 214         p->tss.fs = get_fs().seg;
 215
 216         /* Copy the current fpu state */
 217         asm volatile ("fsave %0" : : "m" (p->tss.fpstate[0]) : "memory");
 218
 219         if (!CPU_IS_060 ? p->tss.fpstate[0] : p->tss.fpstate[2])
 220           asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 221                         "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 222                         : : "m" (p->tss.fp[0]), "m" (p->tss.fpcntl[0])
 223                         : "memory");
 224         /* Restore the state in case the fpu was busy */
 225         asm volatile ("frestore %0" : : "m" (p->tss.fpstate[0]));
 226
 227         return 0;
 228 }
 229
 230 /* Fill in the fpu structure for a core dump.  */
 231
 232 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 233 {
 234   char fpustate[216];
 235
 236   /* First dump the fpu context to avoid protocol violation.  */
 237   asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 238   if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 239      return 0;
 240
 241   asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 242                 :: "m" (fpu->fpcntl[0])
 243                 : "memory");
 244   asm volatile ("fmovemx %/fp0-%/fp7,%0"
 245                 :: "m" (fpu->fpregs[0])
 246                 : "memory");
 247   return 1;
 248 }
 249
 250 /*
 251  * fill in the user structure for a core dump..
 252  */
 253 void dump_thread(struct pt_regs * regs, struct user * dump)
 254 {
 255         struct switch_stack *sw;
 256
 257 /* changed the size calculations - should hopefully work better. lbt */
 258         dump->magic = CMAGIC;
 259         dump->start_code = 0;
 260         dump->start_stack = rdusp() & ~(PAGE_SIZE - 1);
 261         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
 262         dump->u_dsize = ((unsigned long) (current->mm->brk +
 263                                           (PAGE_SIZE-1))) >> PAGE_SHIFT;
 264         dump->u_dsize -= dump->u_tsize;
 265         dump->u_ssize = 0;
 266
 267         if (dump->start_stack < TASK_SIZE)
 268                 dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
 269
 270         dump->u_ar0 = (struct user_regs_struct *)((int)&dump->regs - (int)dump);
 271         sw = ((struct switch_stack *)regs) - 1;
 272         dump->regs.d1 = regs->d1;
 273         dump->regs.d2 = regs->d2;
 274         dump->regs.d3 = regs->d3;
 275         dump->regs.d4 = regs->d4;
 276         dump->regs.d5 = regs->d5;
 277         dump->regs.d6 = sw->d6;
 278         dump->regs.d7 = sw->d7;
 279         dump->regs.a0 = regs->a0;
 280         dump->regs.a1 = regs->a1;
 281         dump->regs.a2 = regs->a2;
 282         dump->regs.a3 = sw->a3;
 283         dump->regs.a4 = sw->a4;
 284         dump->regs.a5 = sw->a5;
 285         dump->regs.a6 = sw->a6;
 286         dump->regs.d0 = regs->d0;
 287         dump->regs.orig_d0 = regs->orig_d0;
 288         dump->regs.stkadj = regs->stkadj;
 289         dump->regs.sr = regs->sr;
 290         dump->regs.pc = regs->pc;
 291         dump->regs.fmtvec = (regs->format << 12) | regs->vector;
 292         /* dump floating point stuff */
 293         dump->u_fpvalid = dump_fpu (regs, &dump->m68kfp);
 294 }
 295
 296 /*
 297  * sys_execve() executes a new program.
 298  */
 299 asmlinkage int sys_execve(char *name, char **argv, char **envp)
 300 {
 301         int error;
 302         char * filename;
 303         struct pt_regs *regs = (struct pt_regs *) &name;
 304
 305         lock_kernel();
 306         filename = getname(name);
 307         error = PTR_ERR(filename);
 308         if (IS_ERR(filename))
 309                 goto out;
 310         error = do_execve(filename, argv, envp, regs);
 311         putname(filename);
 312 out:
 313         unlock_kernel();
 314         return error;
 315 }