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
  44 /*
  45  * Return saved PC from a blocked thread
  46  */
  47 unsigned long thread_saved_pc(struct task_struct *tsk)
  48 {
  49         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  50         /* Check whether the thread is blocked in resume() */
  51         if (in_sched_functions(sw->retpc))
  52                 return ((unsigned long *)sw->a6)[1];
  53         else
  54                 return sw->retpc;
  55 }
  56
  57 void arch_cpu_idle(void)
  58 {
  59 #if defined(MACH_ATARI_ONLY)
  60         /* block out HSYNC on the atari (falcon) */
  61         __asm__("stop #0x2200" : : : "cc");
  62 #else
  63         __asm__("stop #0x2000" : : : "cc");
  64 #endif
  65 }
  66
  67 void machine_restart(char * __unused)
  68 {
  69         if (mach_reset)
  70                 mach_reset();
  71         for (;;);
  72 }
  73
  74 void machine_halt(void)
  75 {
  76         if (mach_halt)
  77                 mach_halt();
  78         for (;;);
  79 }
  80
  81 void machine_power_off(void)
  82 {
  83         if (mach_power_off)
  84                 mach_power_off();
  85         for (;;);
  86 }
  87
  88 void (*pm_power_off)(void) = machine_power_off;
  89 EXPORT_SYMBOL(pm_power_off);
  90
  91 void show_regs(struct pt_regs * regs)
  92 {
  93         pr_info("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
  94                 regs->format, regs->vector, regs->pc, regs->sr,
  95                 print_tainted());
  96         pr_info("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
  97                 regs->orig_d0, regs->d0, regs->a2, regs->a1);
  98         pr_info("A0: %08lx  D5: %08lx  D4: %08lx\n", regs->a0, regs->d5,
  99                 regs->d4);
 100         pr_info("D3: %08lx  D2: %08lx  D1: %08lx\n", regs->d3, regs->d2,
 101                 regs->d1);
 102         if (!(regs->sr & PS_S))
 103                 pr_info("USP: %08lx\n", rdusp());
 104 }
 105
 106 void flush_thread(void)
 107 {
 108         current->thread.fs = __USER_DS;
 109 #ifdef CONFIG_FPU
 110         if (!FPU_IS_EMU) {
 111                 unsigned long zero = 0;
 112                 asm volatile("frestore %0": :"m" (zero));
 113         }
 114 #endif
 115 }
 116
 117 /*
 118  * Why not generic sys_clone, you ask?  m68k passes all arguments on stack.
 119  * And we need all registers saved, which means a bunch of stuff pushed
 120  * on top of pt_regs, which means that sys_clone() arguments would be
 121  * buried.  We could, of course, copy them, but it's too costly for no
 122  * good reason - generic clone() would have to copy them *again* for
 123  * do_fork() anyway.  So in this case it's actually better to pass pt_regs *
 124  * and extract arguments for do_fork() from there.  Eventually we might
 125  * go for calling do_fork() directly from the wrapper, but only after we
 126  * are finished with do_fork() prototype conversion.
 127  */
 128 asmlinkage int m68k_clone(struct pt_regs *regs)
 129 {
 130         /* regs will be equal to current_pt_regs() */
 131         return do_fork(regs->d1, regs->d2, 0,
 132                        (int __user *)regs->d3, (int __user *)regs->d4);
 133 }
 134
 135 int copy_thread(unsigned long clone_flags, unsigned long usp,
 136                  unsigned long arg, struct task_struct *p)
 137 {
 138         struct fork_frame {
 139                 struct switch_stack sw;
 140                 struct pt_regs regs;
 141         } *frame;
 142
 143         frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
 144
 145         p->thread.ksp = (unsigned long)frame;
 146         p->thread.esp0 = (unsigned long)&frame->regs;
 147
 148         /*
 149          * Must save the current SFC/DFC value, NOT the value when
 150          * the parent was last descheduled - RGH  10-08-96
 151          */
 152         p->thread.fs = get_fs().seg;
 153
 154         if (unlikely(p->flags & PF_KTHREAD)) {
 155                 /* kernel thread */
 156                 memset(frame, 0, sizeof(struct fork_frame));
 157                 frame->regs.sr = PS_S;
 158                 frame->sw.a3 = usp; /* function */
 159                 frame->sw.d7 = arg;
 160                 frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
 161                 p->thread.usp = 0;
 162                 return 0;
 163         }
 164         memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
 165                 sizeof(struct fork_frame));
 166         frame->regs.d0 = 0;
 167         frame->sw.retpc = (unsigned long)ret_from_fork;
 168         p->thread.usp = usp ?: rdusp();
 169
 170         if (clone_flags & CLONE_SETTLS)
 171                 task_thread_info(p)->tp_value = frame->regs.d5;
 172
 173 #ifdef CONFIG_FPU
 174         if (!FPU_IS_EMU) {
 175                 /* Copy the current fpu state */
 176                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 177
 178                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
 179                         if (CPU_IS_COLDFIRE) {
 180                                 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
 181                                               "fmovel %/fpiar,%1\n\t"
 182                                               "fmovel %/fpcr,%2\n\t"
 183                                               "fmovel %/fpsr,%3"
 184                                               :
 185                                               : "m" (p->thread.fp[0]),
 186                                                 "m" (p->thread.fpcntl[0]),
 187                                                 "m" (p->thread.fpcntl[1]),
 188                                                 "m" (p->thread.fpcntl[2])
 189                                               : "memory");
 190                         } else {
 191                                 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 192                                               "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 193                                               :
 194                                               : "m" (p->thread.fp[0]),
 195                                                 "m" (p->thread.fpcntl[0])
 196                                               : "memory");
 197                         }
 198                 }
 199
 200                 /* Restore the state in case the fpu was busy */
 201                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 202         }
 203 #endif /* CONFIG_FPU */
 204
 205         return 0;
 206 }
 207
 208 /* Fill in the fpu structure for a core dump.  */
 209 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 210 {
 211         if (FPU_IS_EMU) {
 212                 int i;
 213
 214                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 215                 memcpy(fpu->fpregs, current->thread.fp, 96);
 216                 /* Convert internal fpu reg representation
 217                  * into long double format
 218                  */
 219                 for (i = 0; i < 24; i += 3)
 220                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 221                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 222                 return 1;
 223         }
 224
 225         if (IS_ENABLED(CONFIG_FPU)) {
 226                 char fpustate[216];
 227
 228                 /* First dump the fpu context to avoid protocol violation.  */
 229                 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 230                 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 231                         return 0;
 232
 233                 if (CPU_IS_COLDFIRE) {
 234                         asm volatile ("fmovel %/fpiar,%0\n\t"
 235                                       "fmovel %/fpcr,%1\n\t"
 236                                       "fmovel %/fpsr,%2\n\t"
 237                                       "fmovemd %/fp0-%/fp7,%3"
 238                                       :
 239                                       : "m" (fpu->fpcntl[0]),
 240                                         "m" (fpu->fpcntl[1]),
 241                                         "m" (fpu->fpcntl[2]),
 242                                         "m" (fpu->fpregs[0])
 243                                       : "memory");
 244                 } else {
 245                         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 246                                       :
 247                                       : "m" (fpu->fpcntl[0])
 248                                       : "memory");
 249                         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 250                                       :
 251                                       : "m" (fpu->fpregs[0])
 252                                       : "memory");
 253                 }
 254         }
 255
 256         return 1;
 257 }
 258 EXPORT_SYMBOL(dump_fpu);
 259
 260 unsigned long get_wchan(struct task_struct *p)
 261 {
 262         unsigned long fp, pc;
 263         unsigned long stack_page;
 264         int count = 0;
 265         if (!p || p == current || p->state == TASK_RUNNING)
 266                 return 0;
 267
 268         stack_page = (unsigned long)task_stack_page(p);
 269         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 270         do {
 271                 if (fp < stack_page+sizeof(struct thread_info) ||
 272                     fp >= 8184+stack_page)
 273                         return 0;
 274                 pc = ((unsigned long *)fp)[1];
 275                 if (!in_sched_functions(pc))
 276                         return pc;
 277                 fp = *(unsigned long *) fp;
 278         } while (count++ < 16);
 279         return 0;
 280 }