arch/m68k/kernel/process.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/arch/m68k/kernel/process.c
   4  *
   5  *  Copyright (C) 1995  Hamish Macdonald
   6  *
   7  *  68060 fixes by Jesper Skov
   8  */
   9
  10 /*
  11  * This file handles the architecture-dependent parts of process handling..
  12  */
  13
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/sched/debug.h>
  18 #include <linux/sched/task.h>
  19 #include <linux/sched/task_stack.h>
  20 #include <linux/kernel.h>
  21 #include <linux/mm.h>
  22 #include <linux/slab.h>
  23 #include <linux/fs.h>
  24 #include <linux/smp.h>
  25 #include <linux/stddef.h>
  26 #include <linux/unistd.h>
  27 #include <linux/ptrace.h>
  28 #include <linux/user.h>
  29 #include <linux/reboot.h>
  30 #include <linux/init_task.h>
  31 #include <linux/mqueue.h>
  32 #include <linux/rcupdate.h>
  33
  34 #include <linux/uaccess.h>
  35 #include <asm/traps.h>
  36 #include <asm/machdep.h>
  37 #include <asm/setup.h>
  38 #include <asm/pgtable.h>
  39
  40
  41 asmlinkage void ret_from_fork(void);
  42 asmlinkage void ret_from_kernel_thread(void);
  43
  44 void arch_cpu_idle(void)
  45 {
  46 #if defined(MACH_ATARI_ONLY)
  47         /* block out HSYNC on the atari (falcon) */
  48         __asm__("stop #0x2200" : : : "cc");
  49 #else
  50         __asm__("stop #0x2000" : : : "cc");
  51 #endif
  52 }
  53
  54 void machine_restart(char * __unused)
  55 {
  56         if (mach_reset)
  57                 mach_reset();
  58         for (;;);
  59 }
  60
  61 void machine_halt(void)
  62 {
  63         if (mach_halt)
  64                 mach_halt();
  65         for (;;);
  66 }
  67
  68 void machine_power_off(void)
  69 {
  70         if (mach_power_off)
  71                 mach_power_off();
  72         for (;;);
  73 }
  74
  75 void (*pm_power_off)(void) = machine_power_off;
  76 EXPORT_SYMBOL(pm_power_off);
  77
  78 void show_regs(struct pt_regs * regs)
  79 {
  80         pr_info("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
  81                 regs->format, regs->vector, regs->pc, regs->sr,
  82                 print_tainted());
  83         pr_info("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
  84                 regs->orig_d0, regs->d0, regs->a2, regs->a1);
  85         pr_info("A0: %08lx  D5: %08lx  D4: %08lx\n", regs->a0, regs->d5,
  86                 regs->d4);
  87         pr_info("D3: %08lx  D2: %08lx  D1: %08lx\n", regs->d3, regs->d2,
  88                 regs->d1);
  89         if (!(regs->sr & PS_S))
  90                 pr_info("USP: %08lx\n", rdusp());
  91 }
  92
  93 void flush_thread(void)
  94 {
  95         current->thread.fs = __USER_DS;
  96 #ifdef CONFIG_FPU
  97         if (!FPU_IS_EMU) {
  98                 unsigned long zero = 0;
  99                 asm volatile("frestore %0": :"m" (zero));
 100         }
 101 #endif
 102 }
 103
 104 /*
 105  * Why not generic sys_clone, you ask?  m68k passes all arguments on stack.
 106  * And we need all registers saved, which means a bunch of stuff pushed
 107  * on top of pt_regs, which means that sys_clone() arguments would be
 108  * buried.  We could, of course, copy them, but it's too costly for no
 109  * good reason - generic clone() would have to copy them *again* for
 110  * do_fork() anyway.  So in this case it's actually better to pass pt_regs *
 111  * and extract arguments for do_fork() from there.  Eventually we might
 112  * go for calling do_fork() directly from the wrapper, but only after we
 113  * are finished with do_fork() prototype conversion.
 114  */
 115 asmlinkage int m68k_clone(struct pt_regs *regs)
 116 {
 117         /* regs will be equal to current_pt_regs() */
 118         return do_fork(regs->d1, regs->d2, 0,
 119                        (int __user *)regs->d3, (int __user *)regs->d4);
 120 }
 121
 122 int copy_thread(unsigned long clone_flags, unsigned long usp,
 123                  unsigned long arg, struct task_struct *p)
 124 {
 125         struct fork_frame {
 126                 struct switch_stack sw;
 127                 struct pt_regs regs;
 128         } *frame;
 129
 130         frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
 131
 132         p->thread.ksp = (unsigned long)frame;
 133         p->thread.esp0 = (unsigned long)&frame->regs;
 134
 135         /*
 136          * Must save the current SFC/DFC value, NOT the value when
 137          * the parent was last descheduled - RGH  10-08-96
 138          */
 139         p->thread.fs = get_fs().seg;
 140
 141         if (unlikely(p->flags & PF_KTHREAD)) {
 142                 /* kernel thread */
 143                 memset(frame, 0, sizeof(struct fork_frame));
 144                 frame->regs.sr = PS_S;
 145                 frame->sw.a3 = usp; /* function */
 146                 frame->sw.d7 = arg;
 147                 frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
 148                 p->thread.usp = 0;
 149                 return 0;
 150         }
 151         memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
 152                 sizeof(struct fork_frame));
 153         frame->regs.d0 = 0;
 154         frame->sw.retpc = (unsigned long)ret_from_fork;
 155         p->thread.usp = usp ?: rdusp();
 156
 157         if (clone_flags & CLONE_SETTLS)
 158                 task_thread_info(p)->tp_value = frame->regs.d5;
 159
 160 #ifdef CONFIG_FPU
 161         if (!FPU_IS_EMU) {
 162                 /* Copy the current fpu state */
 163                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 164
 165                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
 166                         if (CPU_IS_COLDFIRE) {
 167                                 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
 168                                               "fmovel %/fpiar,%1\n\t"
 169                                               "fmovel %/fpcr,%2\n\t"
 170                                               "fmovel %/fpsr,%3"
 171                                               :
 172                                               : "m" (p->thread.fp[0]),
 173                                                 "m" (p->thread.fpcntl[0]),
 174                                                 "m" (p->thread.fpcntl[1]),
 175                                                 "m" (p->thread.fpcntl[2])
 176                                               : "memory");
 177                         } else {
 178                                 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 179                                               "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 180                                               :
 181                                               : "m" (p->thread.fp[0]),
 182                                                 "m" (p->thread.fpcntl[0])
 183                                               : "memory");
 184                         }
 185                 }
 186
 187                 /* Restore the state in case the fpu was busy */
 188                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 189         }
 190 #endif /* CONFIG_FPU */
 191
 192         return 0;
 193 }
 194
 195 /* Fill in the fpu structure for a core dump.  */
 196 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 197 {
 198         if (FPU_IS_EMU) {
 199                 int i;
 200
 201                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 202                 memcpy(fpu->fpregs, current->thread.fp, 96);
 203                 /* Convert internal fpu reg representation
 204                  * into long double format
 205                  */
 206                 for (i = 0; i < 24; i += 3)
 207                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 208                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 209                 return 1;
 210         }
 211
 212         if (IS_ENABLED(CONFIG_FPU)) {
 213                 char fpustate[216];
 214
 215                 /* First dump the fpu context to avoid protocol violation.  */
 216                 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 217                 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 218                         return 0;
 219
 220                 if (CPU_IS_COLDFIRE) {
 221                         asm volatile ("fmovel %/fpiar,%0\n\t"
 222                                       "fmovel %/fpcr,%1\n\t"
 223                                       "fmovel %/fpsr,%2\n\t"
 224                                       "fmovemd %/fp0-%/fp7,%3"
 225                                       :
 226                                       : "m" (fpu->fpcntl[0]),
 227                                         "m" (fpu->fpcntl[1]),
 228                                         "m" (fpu->fpcntl[2]),
 229                                         "m" (fpu->fpregs[0])
 230                                       : "memory");
 231                 } else {
 232                         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 233                                       :
 234                                       : "m" (fpu->fpcntl[0])
 235                                       : "memory");
 236                         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 237                                       :
 238                                       : "m" (fpu->fpregs[0])
 239                                       : "memory");
 240                 }
 241         }
 242
 243         return 1;
 244 }
 245 EXPORT_SYMBOL(dump_fpu);
 246
 247 unsigned long get_wchan(struct task_struct *p)
 248 {
 249         unsigned long fp, pc;
 250         unsigned long stack_page;
 251         int count = 0;
 252         if (!p || p == current || p->state == TASK_RUNNING)
 253                 return 0;
 254
 255         stack_page = (unsigned long)task_stack_page(p);
 256         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 257         do {
 258                 if (fp < stack_page+sizeof(struct thread_info) ||
 259                     fp >= 8184+stack_page)
 260                         return 0;
 261                 pc = ((unsigned long *)fp)[1];
 262                 if (!in_sched_functions(pc))
 263                         return pc;
 264                 fp = *(unsigned long *) fp;
 265         } while (count++ < 16);
 266         return 0;
 267 }