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 #include <linux/rcupdate.h>
  29
  30 #include <asm/uaccess.h>
  31 #include <asm/traps.h>
  32 #include <asm/machdep.h>
  33 #include <asm/setup.h>
  34 #include <asm/pgtable.h>
  35
  36
  37 asmlinkage void ret_from_fork(void);
  38 asmlinkage void ret_from_kernel_thread(void);
  39
  40
  41 /*
  42  * Return saved PC from a blocked thread
  43  */
  44 unsigned long thread_saved_pc(struct task_struct *tsk)
  45 {
  46         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  47         /* Check whether the thread is blocked in resume() */
  48         if (in_sched_functions(sw->retpc))
  49                 return ((unsigned long *)sw->a6)[1];
  50         else
  51                 return sw->retpc;
  52 }
  53
  54 void arch_cpu_idle(void)
  55 {
  56 #if defined(MACH_ATARI_ONLY)
  57         /* block out HSYNC on the atari (falcon) */
  58         __asm__("stop #0x2200" : : : "cc");
  59 #else
  60         __asm__("stop #0x2000" : : : "cc");
  61 #endif
  62 }
  63
  64 void machine_restart(char * __unused)
  65 {
  66         if (mach_reset)
  67                 mach_reset();
  68         for (;;);
  69 }
  70
  71 void machine_halt(void)
  72 {
  73         if (mach_halt)
  74                 mach_halt();
  75         for (;;);
  76 }
  77
  78 void machine_power_off(void)
  79 {
  80         if (mach_power_off)
  81                 mach_power_off();
  82         for (;;);
  83 }
  84
  85 void (*pm_power_off)(void) = machine_power_off;
  86 EXPORT_SYMBOL(pm_power_off);
  87
  88 void show_regs(struct pt_regs * regs)
  89 {
  90         printk("\n");
  91         printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
  92                regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
  93         printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
  94                regs->orig_d0, regs->d0, regs->a2, regs->a1);
  95         printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
  96                regs->a0, regs->d5, regs->d4);
  97         printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
  98                regs->d3, regs->d2, regs->d1);
  99         if (!(regs->sr & PS_S))
 100                 printk("USP: %08lx\n", rdusp());
 101 }
 102
 103 void flush_thread(void)
 104 {
 105         current->thread.fs = __USER_DS;
 106 #ifdef CONFIG_FPU
 107         if (!FPU_IS_EMU) {
 108                 unsigned long zero = 0;
 109                 asm volatile("frestore %0": :"m" (zero));
 110         }
 111 #endif
 112 }
 113
 114 /*
 115  * Why not generic sys_clone, you ask?  m68k passes all arguments on stack.
 116  * And we need all registers saved, which means a bunch of stuff pushed
 117  * on top of pt_regs, which means that sys_clone() arguments would be
 118  * buried.  We could, of course, copy them, but it's too costly for no
 119  * good reason - generic clone() would have to copy them *again* for
 120  * do_fork() anyway.  So in this case it's actually better to pass pt_regs *
 121  * and extract arguments for do_fork() from there.  Eventually we might
 122  * go for calling do_fork() directly from the wrapper, but only after we
 123  * are finished with do_fork() prototype conversion.
 124  */
 125 asmlinkage int m68k_clone(struct pt_regs *regs)
 126 {
 127         /* regs will be equal to current_pt_regs() */
 128         return do_fork(regs->d1, regs->d2, 0,
 129                        (int __user *)regs->d3, (int __user *)regs->d4);
 130 }
 131
 132 int copy_thread(unsigned long clone_flags, unsigned long usp,
 133                  unsigned long arg, struct task_struct *p)
 134 {
 135         struct fork_frame {
 136                 struct switch_stack sw;
 137                 struct pt_regs regs;
 138         } *frame;
 139
 140         frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
 141
 142         p->thread.ksp = (unsigned long)frame;
 143         p->thread.esp0 = (unsigned long)&frame->regs;
 144
 145         /*
 146          * Must save the current SFC/DFC value, NOT the value when
 147          * the parent was last descheduled - RGH  10-08-96
 148          */
 149         p->thread.fs = get_fs().seg;
 150
 151         if (unlikely(p->flags & PF_KTHREAD)) {
 152                 /* kernel thread */
 153                 memset(frame, 0, sizeof(struct fork_frame));
 154                 frame->regs.sr = PS_S;
 155                 frame->sw.a3 = usp; /* function */
 156                 frame->sw.d7 = arg;
 157                 frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
 158                 p->thread.usp = 0;
 159                 return 0;
 160         }
 161         memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
 162                 sizeof(struct fork_frame));
 163         frame->regs.d0 = 0;
 164         frame->sw.retpc = (unsigned long)ret_from_fork;
 165         p->thread.usp = usp ?: rdusp();
 166
 167         if (clone_flags & CLONE_SETTLS)
 168                 task_thread_info(p)->tp_value = frame->regs.d5;
 169
 170 #ifdef CONFIG_FPU
 171         if (!FPU_IS_EMU) {
 172                 /* Copy the current fpu state */
 173                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 174
 175                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
 176                         if (CPU_IS_COLDFIRE) {
 177                                 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
 178                                               "fmovel %/fpiar,%1\n\t"
 179                                               "fmovel %/fpcr,%2\n\t"
 180                                               "fmovel %/fpsr,%3"
 181                                               :
 182                                               : "m" (p->thread.fp[0]),
 183                                                 "m" (p->thread.fpcntl[0]),
 184                                                 "m" (p->thread.fpcntl[1]),
 185                                                 "m" (p->thread.fpcntl[2])
 186                                               : "memory");
 187                         } else {
 188                                 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 189                                               "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 190                                               :
 191                                               : "m" (p->thread.fp[0]),
 192                                                 "m" (p->thread.fpcntl[0])
 193                                               : "memory");
 194                         }
 195                 }
 196
 197                 /* Restore the state in case the fpu was busy */
 198                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 199         }
 200 #endif /* CONFIG_FPU */
 201
 202         return 0;
 203 }
 204
 205 /* Fill in the fpu structure for a core dump.  */
 206 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 207 {
 208         if (FPU_IS_EMU) {
 209                 int i;
 210
 211                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 212                 memcpy(fpu->fpregs, current->thread.fp, 96);
 213                 /* Convert internal fpu reg representation
 214                  * into long double format
 215                  */
 216                 for (i = 0; i < 24; i += 3)
 217                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 218                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 219                 return 1;
 220         }
 221
 222         if (IS_ENABLED(CONFIG_FPU)) {
 223                 char fpustate[216];
 224
 225                 /* First dump the fpu context to avoid protocol violation.  */
 226                 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 227                 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 228                         return 0;
 229
 230                 if (CPU_IS_COLDFIRE) {
 231                         asm volatile ("fmovel %/fpiar,%0\n\t"
 232                                       "fmovel %/fpcr,%1\n\t"
 233                                       "fmovel %/fpsr,%2\n\t"
 234                                       "fmovemd %/fp0-%/fp7,%3"
 235                                       :
 236                                       : "m" (fpu->fpcntl[0]),
 237                                         "m" (fpu->fpcntl[1]),
 238                                         "m" (fpu->fpcntl[2]),
 239                                         "m" (fpu->fpregs[0])
 240                                       : "memory");
 241                 } else {
 242                         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 243                                       :
 244                                       : "m" (fpu->fpcntl[0])
 245                                       : "memory");
 246                         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 247                                       :
 248                                       : "m" (fpu->fpregs[0])
 249                                       : "memory");
 250                 }
 251         }
 252
 253         return 1;
 254 }
 255 EXPORT_SYMBOL(dump_fpu);
 256
 257 unsigned long get_wchan(struct task_struct *p)
 258 {
 259         unsigned long fp, pc;
 260         unsigned long stack_page;
 261         int count = 0;
 262         if (!p || p == current || p->state == TASK_RUNNING)
 263                 return 0;
 264
 265         stack_page = (unsigned long)task_stack_page(p);
 266         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 267         do {
 268                 if (fp < stack_page+sizeof(struct thread_info) ||
 269                     fp >= 8184+stack_page)
 270                         return 0;
 271                 pc = ((unsigned long *)fp)[1];
 272                 if (!in_sched_functions(pc))
 273                         return pc;
 274                 fp = *(unsigned long *) fp;
 275         } while (count++ < 16);
 276         return 0;
 277 }