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