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 #include <linux/syscalls.h>
  34 #include <linux/uaccess.h>
  35
  36 #include <asm/traps.h>
  37 #include <asm/machdep.h>
  38 #include <asm/setup.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         do_kernel_power_off();
  71         for (;;);
  72 }
  73
  74 void (*pm_power_off)(void);
  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.fc = USER_DATA;
  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  * kernel_clone() anyway.  So in this case it's actually better to pass pt_regs *
 110  * and extract arguments for kernel_clone() from there.  Eventually we might
 111  * go for calling kernel_clone() directly from the wrapper, but only after we
 112  * are finished with kernel_clone() prototype conversion.
 113  */
 114 asmlinkage int m68k_clone(struct pt_regs *regs)
 115 {
 116         /* regs will be equal to current_pt_regs() */
 117         struct kernel_clone_args args = {
 118                 .flags          = regs->d1 & ~CSIGNAL,
 119                 .pidfd          = (int __user *)regs->d3,
 120                 .child_tid      = (int __user *)regs->d4,
 121                 .parent_tid     = (int __user *)regs->d3,
 122                 .exit_signal    = regs->d1 & CSIGNAL,
 123                 .stack          = regs->d2,
 124                 .tls            = regs->d5,
 125         };
 126
 127         return kernel_clone(&args);
 128 }
 129
 130 /*
 131  * Because extra registers are saved on the stack after the sys_clone3()
 132  * arguments, this C wrapper extracts them from pt_regs * and then calls the
 133  * generic sys_clone3() implementation.
 134  */
 135 asmlinkage int m68k_clone3(struct pt_regs *regs)
 136 {
 137         return sys_clone3((struct clone_args __user *)regs->d1, regs->d2);
 138 }
 139
 140 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 141 {
 142         unsigned long clone_flags = args->flags;
 143         unsigned long usp = args->stack;
 144         unsigned long tls = args->tls;
 145         struct fork_frame {
 146                 struct switch_stack sw;
 147                 struct pt_regs regs;
 148         } *frame;
 149
 150         frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
 151
 152         p->thread.ksp = (unsigned long)frame;
 153         p->thread.esp0 = (unsigned long)&frame->regs;
 154
 155         /*
 156          * Must save the current SFC/DFC value, NOT the value when
 157          * the parent was last descheduled - RGH  10-08-96
 158          */
 159         p->thread.fc = USER_DATA;
 160
 161         if (unlikely(args->fn)) {
 162                 /* kernel thread */
 163                 memset(frame, 0, sizeof(struct fork_frame));
 164                 frame->regs.sr = PS_S;
 165                 frame->sw.a3 = (unsigned long)args->fn;
 166                 frame->sw.d7 = (unsigned long)args->fn_arg;
 167                 frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
 168                 p->thread.usp = 0;
 169                 return 0;
 170         }
 171         memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
 172                 sizeof(struct fork_frame));
 173         frame->regs.d0 = 0;
 174         frame->sw.retpc = (unsigned long)ret_from_fork;
 175         p->thread.usp = usp ?: rdusp();
 176
 177         if (clone_flags & CLONE_SETTLS)
 178                 task_thread_info(p)->tp_value = tls;
 179
 180 #ifdef CONFIG_FPU
 181         if (!FPU_IS_EMU) {
 182                 /* Copy the current fpu state */
 183                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 184
 185                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
 186                         if (CPU_IS_COLDFIRE) {
 187                                 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
 188                                               "fmovel %/fpiar,%1\n\t"
 189                                               "fmovel %/fpcr,%2\n\t"
 190                                               "fmovel %/fpsr,%3"
 191                                               :
 192                                               : "m" (p->thread.fp[0]),
 193                                                 "m" (p->thread.fpcntl[0]),
 194                                                 "m" (p->thread.fpcntl[1]),
 195                                                 "m" (p->thread.fpcntl[2])
 196                                               : "memory");
 197                         } else {
 198                                 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 199                                               "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 200                                               :
 201                                               : "m" (p->thread.fp[0]),
 202                                                 "m" (p->thread.fpcntl[0])
 203                                               : "memory");
 204                         }
 205                 }
 206
 207                 /* Restore the state in case the fpu was busy */
 208                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 209         }
 210 #endif /* CONFIG_FPU */
 211
 212         return 0;
 213 }
 214
 215 /* Fill in the fpu structure for a core dump.  */
 216 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 217 {
 218         if (FPU_IS_EMU) {
 219                 int i;
 220
 221                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 222                 memcpy(fpu->fpregs, current->thread.fp, 96);
 223                 /* Convert internal fpu reg representation
 224                  * into long double format
 225                  */
 226                 for (i = 0; i < 24; i += 3)
 227                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 228                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 229                 return 1;
 230         }
 231
 232         if (IS_ENABLED(CONFIG_FPU)) {
 233                 char fpustate[216];
 234
 235                 /* First dump the fpu context to avoid protocol violation.  */
 236                 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 237                 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 238                         return 0;
 239
 240                 if (CPU_IS_COLDFIRE) {
 241                         asm volatile ("fmovel %/fpiar,%0\n\t"
 242                                       "fmovel %/fpcr,%1\n\t"
 243                                       "fmovel %/fpsr,%2\n\t"
 244                                       "fmovemd %/fp0-%/fp7,%3"
 245                                       :
 246                                       : "m" (fpu->fpcntl[0]),
 247                                         "m" (fpu->fpcntl[1]),
 248                                         "m" (fpu->fpcntl[2]),
 249                                         "m" (fpu->fpregs[0])
 250                                       : "memory");
 251                 } else {
 252                         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 253                                       :
 254                                       : "m" (fpu->fpcntl[0])
 255                                       : "memory");
 256                         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 257                                       :
 258                                       : "m" (fpu->fpregs[0])
 259                                       : "memory");
 260                 }
 261         }
 262
 263         return 1;
 264 }
 265 EXPORT_SYMBOL(dump_fpu);
 266
 267 unsigned long __get_wchan(struct task_struct *p)
 268 {
 269         unsigned long fp, pc;
 270         unsigned long stack_page;
 271         int count = 0;
 272
 273         stack_page = (unsigned long)task_stack_page(p);
 274         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 275         do {
 276                 if (fp < stack_page+sizeof(struct thread_info) ||
 277                     fp >= 8184+stack_page)
 278                         return 0;
 279                 pc = ((unsigned long *)fp)[1];
 280                 if (!in_sched_functions(pc))
 281                         return pc;
 282                 fp = *(unsigned long *) fp;
 283         } while (count++ < 16);
 284         return 0;
 285 }