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 #include <linux/elfcore.h>
  36
  37 #include <asm/traps.h>
  38 #include <asm/machdep.h>
  39 #include <asm/setup.h>
  40
  41 #include "process.h"
  42
  43 asmlinkage void ret_from_fork(void);
  44 asmlinkage void ret_from_kernel_thread(void);
  45
  46 void arch_cpu_idle(void)
  47 {
  48 #if defined(MACH_ATARI_ONLY)
  49         /* block out HSYNC on the atari (falcon) */
  50         __asm__("stop #0x2200" : : : "cc");
  51 #else
  52         __asm__("stop #0x2000" : : : "cc");
  53 #endif
  54 }
  55
  56 void machine_restart(char * __unused)
  57 {
  58         if (mach_reset)
  59                 mach_reset();
  60         for (;;);
  61 }
  62
  63 void machine_halt(void)
  64 {
  65         if (mach_halt)
  66                 mach_halt();
  67         for (;;);
  68 }
  69
  70 void machine_power_off(void)
  71 {
  72         do_kernel_power_off();
  73         for (;;);
  74 }
  75
  76 void (*pm_power_off)(void);
  77 EXPORT_SYMBOL(pm_power_off);
  78
  79 void show_regs(struct pt_regs * regs)
  80 {
  81         pr_info("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
  82                 regs->format, regs->vector, regs->pc, regs->sr,
  83                 print_tainted());
  84         pr_info("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
  85                 regs->orig_d0, regs->d0, regs->a2, regs->a1);
  86         pr_info("A0: %08lx  D5: %08lx  D4: %08lx\n", regs->a0, regs->d5,
  87                 regs->d4);
  88         pr_info("D3: %08lx  D2: %08lx  D1: %08lx\n", regs->d3, regs->d2,
  89                 regs->d1);
  90         if (!(regs->sr & PS_S))
  91                 pr_info("USP: %08lx\n", rdusp());
  92 }
  93
  94 void flush_thread(void)
  95 {
  96         current->thread.fc = USER_DATA;
  97 #ifdef CONFIG_FPU
  98         if (!FPU_IS_EMU) {
  99                 unsigned long zero = 0;
 100                 asm volatile("frestore %0": :"m" (zero));
 101         }
 102 #endif
 103 }
 104
 105 /*
 106  * Why not generic sys_clone, you ask?  m68k passes all arguments on stack.
 107  * And we need all registers saved, which means a bunch of stuff pushed
 108  * on top of pt_regs, which means that sys_clone() arguments would be
 109  * buried.  We could, of course, copy them, but it's too costly for no
 110  * good reason - generic clone() would have to copy them *again* for
 111  * kernel_clone() anyway.  So in this case it's actually better to pass pt_regs *
 112  * and extract arguments for kernel_clone() from there.  Eventually we might
 113  * go for calling kernel_clone() directly from the wrapper, but only after we
 114  * are finished with kernel_clone() prototype conversion.
 115  */
 116 asmlinkage int m68k_clone(struct pt_regs *regs)
 117 {
 118         /* regs will be equal to current_pt_regs() */
 119         struct kernel_clone_args args = {
 120                 .flags          = (u32)(regs->d1) & ~CSIGNAL,
 121                 .pidfd          = (int __user *)regs->d3,
 122                 .child_tid      = (int __user *)regs->d4,
 123                 .parent_tid     = (int __user *)regs->d3,
 124                 .exit_signal    = regs->d1 & CSIGNAL,
 125                 .stack          = regs->d2,
 126                 .tls            = regs->d5,
 127         };
 128
 129         return kernel_clone(&args);
 130 }
 131
 132 /*
 133  * Because extra registers are saved on the stack after the sys_clone3()
 134  * arguments, this C wrapper extracts them from pt_regs * and then calls the
 135  * generic sys_clone3() implementation.
 136  */
 137 asmlinkage int m68k_clone3(struct pt_regs *regs)
 138 {
 139         return sys_clone3((struct clone_args __user *)regs->d1, regs->d2);
 140 }
 141
 142 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 143 {
 144         unsigned long clone_flags = args->flags;
 145         unsigned long usp = args->stack;
 146         unsigned long tls = args->tls;
 147         struct fork_frame {
 148                 struct switch_stack sw;
 149                 struct pt_regs regs;
 150         } *frame;
 151
 152         frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
 153
 154         p->thread.ksp = (unsigned long)frame;
 155         p->thread.esp0 = (unsigned long)&frame->regs;
 156
 157         /*
 158          * Must save the current SFC/DFC value, NOT the value when
 159          * the parent was last descheduled - RGH  10-08-96
 160          */
 161         p->thread.fc = USER_DATA;
 162
 163         if (unlikely(args->fn)) {
 164                 /* kernel thread */
 165                 memset(frame, 0, sizeof(struct fork_frame));
 166                 frame->regs.sr = PS_S;
 167                 frame->sw.a3 = (unsigned long)args->fn;
 168                 frame->sw.d7 = (unsigned long)args->fn_arg;
 169                 frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
 170                 p->thread.usp = 0;
 171                 return 0;
 172         }
 173         memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
 174                 sizeof(struct fork_frame));
 175         frame->regs.d0 = 0;
 176         frame->sw.retpc = (unsigned long)ret_from_fork;
 177         p->thread.usp = usp ?: rdusp();
 178
 179         if (clone_flags & CLONE_SETTLS)
 180                 task_thread_info(p)->tp_value = tls;
 181
 182 #ifdef CONFIG_FPU
 183         if (!FPU_IS_EMU) {
 184                 /* Copy the current fpu state */
 185                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 186
 187                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
 188                         if (CPU_IS_COLDFIRE) {
 189                                 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
 190                                               "fmovel %/fpiar,%1\n\t"
 191                                               "fmovel %/fpcr,%2\n\t"
 192                                               "fmovel %/fpsr,%3"
 193                                               :
 194                                               : "m" (p->thread.fp[0]),
 195                                                 "m" (p->thread.fpcntl[0]),
 196                                                 "m" (p->thread.fpcntl[1]),
 197                                                 "m" (p->thread.fpcntl[2])
 198                                               : "memory");
 199                         } else {
 200                                 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 201                                               "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 202                                               :
 203                                               : "m" (p->thread.fp[0]),
 204                                                 "m" (p->thread.fpcntl[0])
 205                                               : "memory");
 206                         }
 207                 }
 208
 209                 /* Restore the state in case the fpu was busy */
 210                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 211         }
 212 #endif /* CONFIG_FPU */
 213
 214         return 0;
 215 }
 216
 217 /* Fill in the fpu structure for a core dump.  */
 218 int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
 219 {
 220         if (FPU_IS_EMU) {
 221                 int i;
 222
 223                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 224                 memcpy(fpu->fpregs, current->thread.fp, 96);
 225                 /* Convert internal fpu reg representation
 226                  * into long double format
 227                  */
 228                 for (i = 0; i < 24; i += 3)
 229                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 230                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 231                 return 1;
 232         }
 233
 234         if (IS_ENABLED(CONFIG_FPU)) {
 235                 char fpustate[216];
 236
 237                 /* First dump the fpu context to avoid protocol violation.  */
 238                 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 239                 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 240                         return 0;
 241
 242                 if (CPU_IS_COLDFIRE) {
 243                         asm volatile ("fmovel %/fpiar,%0\n\t"
 244                                       "fmovel %/fpcr,%1\n\t"
 245                                       "fmovel %/fpsr,%2\n\t"
 246                                       "fmovemd %/fp0-%/fp7,%3"
 247                                       :
 248                                       : "m" (fpu->fpcntl[0]),
 249                                         "m" (fpu->fpcntl[1]),
 250                                         "m" (fpu->fpcntl[2]),
 251                                         "m" (fpu->fpregs[0])
 252                                       : "memory");
 253                 } else {
 254                         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 255                                       :
 256                                       : "m" (fpu->fpcntl[0])
 257                                       : "memory");
 258                         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 259                                       :
 260                                       : "m" (fpu->fpregs[0])
 261                                       : "memory");
 262                 }
 263         }
 264
 265         return 1;
 266 }
 267
 268 unsigned long __get_wchan(struct task_struct *p)
 269 {
 270         unsigned long fp, pc;
 271         unsigned long stack_page;
 272         int count = 0;
 273
 274         stack_page = (unsigned long)task_stack_page(p);
 275         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 276         do {
 277                 if (fp < stack_page+sizeof(struct thread_info) ||
 278                     fp >= 8184+stack_page)
 279                         return 0;
 280                 pc = ((unsigned long *)fp)[1];
 281                 if (!in_sched_functions(pc))
 282                         return pc;
 283                 fp = *(unsigned long *) fp;
 284         } while (count++ < 16);
 285         return 0;
 286 }