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         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         struct kernel_clone_args args = {
 119                 .flags          = regs->d1 & ~CSIGNAL,
 120                 .pidfd          = (int __user *)regs->d3,
 121                 .child_tid      = (int __user *)regs->d4,
 122                 .parent_tid     = (int __user *)regs->d3,
 123                 .exit_signal    = regs->d1 & CSIGNAL,
 124                 .stack          = regs->d2,
 125                 .tls            = regs->d5,
 126         };
 127
 128         if (!legacy_clone_args_valid(&args))
 129                 return -EINVAL;
 130
 131         return _do_fork(&args);
 132 }
 133
 134 /*
 135  * Because extra registers are saved on the stack after the sys_clone3()
 136  * arguments, this C wrapper extracts them from pt_regs * and then calls the
 137  * generic sys_clone3() implementation.
 138  */
 139 asmlinkage int m68k_clone3(struct pt_regs *regs)
 140 {
 141         return sys_clone3((struct clone_args __user *)regs->d1, regs->d2);
 142 }
 143
 144 int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
 145                     unsigned long arg, struct task_struct *p,
 146                     unsigned long tls)
 147 {
 148         struct fork_frame {
 149                 struct switch_stack sw;
 150                 struct pt_regs regs;
 151         } *frame;
 152
 153         frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
 154
 155         p->thread.ksp = (unsigned long)frame;
 156         p->thread.esp0 = (unsigned long)&frame->regs;
 157
 158         /*
 159          * Must save the current SFC/DFC value, NOT the value when
 160          * the parent was last descheduled - RGH  10-08-96
 161          */
 162         p->thread.fs = get_fs().seg;
 163
 164         if (unlikely(p->flags & PF_KTHREAD)) {
 165                 /* kernel thread */
 166                 memset(frame, 0, sizeof(struct fork_frame));
 167                 frame->regs.sr = PS_S;
 168                 frame->sw.a3 = usp; /* function */
 169                 frame->sw.d7 = arg;
 170                 frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
 171                 p->thread.usp = 0;
 172                 return 0;
 173         }
 174         memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
 175                 sizeof(struct fork_frame));
 176         frame->regs.d0 = 0;
 177         frame->sw.retpc = (unsigned long)ret_from_fork;
 178         p->thread.usp = usp ?: rdusp();
 179
 180         if (clone_flags & CLONE_SETTLS)
 181                 task_thread_info(p)->tp_value = tls;
 182
 183 #ifdef CONFIG_FPU
 184         if (!FPU_IS_EMU) {
 185                 /* Copy the current fpu state */
 186                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 187
 188                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
 189                         if (CPU_IS_COLDFIRE) {
 190                                 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
 191                                               "fmovel %/fpiar,%1\n\t"
 192                                               "fmovel %/fpcr,%2\n\t"
 193                                               "fmovel %/fpsr,%3"
 194                                               :
 195                                               : "m" (p->thread.fp[0]),
 196                                                 "m" (p->thread.fpcntl[0]),
 197                                                 "m" (p->thread.fpcntl[1]),
 198                                                 "m" (p->thread.fpcntl[2])
 199                                               : "memory");
 200                         } else {
 201                                 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 202                                               "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 203                                               :
 204                                               : "m" (p->thread.fp[0]),
 205                                                 "m" (p->thread.fpcntl[0])
 206                                               : "memory");
 207                         }
 208                 }
 209
 210                 /* Restore the state in case the fpu was busy */
 211                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 212         }
 213 #endif /* CONFIG_FPU */
 214
 215         return 0;
 216 }
 217
 218 /* Fill in the fpu structure for a core dump.  */
 219 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 220 {
 221         if (FPU_IS_EMU) {
 222                 int i;
 223
 224                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 225                 memcpy(fpu->fpregs, current->thread.fp, 96);
 226                 /* Convert internal fpu reg representation
 227                  * into long double format
 228                  */
 229                 for (i = 0; i < 24; i += 3)
 230                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 231                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 232                 return 1;
 233         }
 234
 235         if (IS_ENABLED(CONFIG_FPU)) {
 236                 char fpustate[216];
 237
 238                 /* First dump the fpu context to avoid protocol violation.  */
 239                 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 240                 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 241                         return 0;
 242
 243                 if (CPU_IS_COLDFIRE) {
 244                         asm volatile ("fmovel %/fpiar,%0\n\t"
 245                                       "fmovel %/fpcr,%1\n\t"
 246                                       "fmovel %/fpsr,%2\n\t"
 247                                       "fmovemd %/fp0-%/fp7,%3"
 248                                       :
 249                                       : "m" (fpu->fpcntl[0]),
 250                                         "m" (fpu->fpcntl[1]),
 251                                         "m" (fpu->fpcntl[2]),
 252                                         "m" (fpu->fpregs[0])
 253                                       : "memory");
 254                 } else {
 255                         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 256                                       :
 257                                       : "m" (fpu->fpcntl[0])
 258                                       : "memory");
 259                         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 260                                       :
 261                                       : "m" (fpu->fpregs[0])
 262                                       : "memory");
 263                 }
 264         }
 265
 266         return 1;
 267 }
 268 EXPORT_SYMBOL(dump_fpu);
 269
 270 unsigned long get_wchan(struct task_struct *p)
 271 {
 272         unsigned long fp, pc;
 273         unsigned long stack_page;
 274         int count = 0;
 275         if (!p || p == current || p->state == TASK_RUNNING)
 276                 return 0;
 277
 278         stack_page = (unsigned long)task_stack_page(p);
 279         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 280         do {
 281                 if (fp < stack_page+sizeof(struct thread_info) ||
 282                     fp >= 8184+stack_page)
 283                         return 0;
 284                 pc = ((unsigned long *)fp)[1];
 285                 if (!in_sched_functions(pc))
 286                         return pc;
 287                 fp = *(unsigned long *) fp;
 288         } while (count++ < 16);
 289         return 0;
 290 }