linux/arch/m68k/kernel/process.c
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   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
  41asmlinkage void ret_from_fork(void);
  42asmlinkage void ret_from_kernel_thread(void);
  43
  44void 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
  54void machine_restart(char * __unused)
  55{
  56        if (mach_reset)
  57                mach_reset();
  58        for (;;);
  59}
  60
  61void machine_halt(void)
  62{
  63        if (mach_halt)
  64                mach_halt();
  65        for (;;);
  66}
  67
  68void machine_power_off(void)
  69{
  70        if (mach_power_off)
  71                mach_power_off();
  72        for (;;);
  73}
  74
  75void (*pm_power_off)(void) = machine_power_off;
  76EXPORT_SYMBOL(pm_power_off);
  77
  78void 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
  93void 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 * kernel_clone() anyway.  So in this case it's actually better to pass pt_regs *
 111 * and extract arguments for kernel_clone() from there.  Eventually we might
 112 * go for calling kernel_clone() directly from the wrapper, but only after we
 113 * are finished with kernel_clone() prototype conversion.
 114 */
 115asmlinkage 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        return kernel_clone(&args);
 129}
 130
 131/*
 132 * Because extra registers are saved on the stack after the sys_clone3()
 133 * arguments, this C wrapper extracts them from pt_regs * and then calls the
 134 * generic sys_clone3() implementation.
 135 */
 136asmlinkage int m68k_clone3(struct pt_regs *regs)
 137{
 138        return sys_clone3((struct clone_args __user *)regs->d1, regs->d2);
 139}
 140
 141int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
 142                struct task_struct *p, unsigned long tls)
 143{
 144        struct fork_frame {
 145                struct switch_stack sw;
 146                struct pt_regs regs;
 147        } *frame;
 148
 149        frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
 150
 151        p->thread.ksp = (unsigned long)frame;
 152        p->thread.esp0 = (unsigned long)&frame->regs;
 153
 154        /*
 155         * Must save the current SFC/DFC value, NOT the value when
 156         * the parent was last descheduled - RGH  10-08-96
 157         */
 158        p->thread.fs = get_fs().seg;
 159
 160        if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
 161                /* kernel thread */
 162                memset(frame, 0, sizeof(struct fork_frame));
 163                frame->regs.sr = PS_S;
 164                frame->sw.a3 = usp; /* function */
 165                frame->sw.d7 = arg;
 166                frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
 167                p->thread.usp = 0;
 168                return 0;
 169        }
 170        memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
 171                sizeof(struct fork_frame));
 172        frame->regs.d0 = 0;
 173        frame->sw.retpc = (unsigned long)ret_from_fork;
 174        p->thread.usp = usp ?: rdusp();
 175
 176        if (clone_flags & CLONE_SETTLS)
 177                task_thread_info(p)->tp_value = tls;
 178
 179#ifdef CONFIG_FPU
 180        if (!FPU_IS_EMU) {
 181                /* Copy the current fpu state */
 182                asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 183
 184                if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
 185                        if (CPU_IS_COLDFIRE) {
 186                                asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
 187                                              "fmovel %/fpiar,%1\n\t"
 188                                              "fmovel %/fpcr,%2\n\t"
 189                                              "fmovel %/fpsr,%3"
 190                                              :
 191                                              : "m" (p->thread.fp[0]),
 192                                                "m" (p->thread.fpcntl[0]),
 193                                                "m" (p->thread.fpcntl[1]),
 194                                                "m" (p->thread.fpcntl[2])
 195                                              : "memory");
 196                        } else {
 197                                asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 198                                              "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 199                                              :
 200                                              : "m" (p->thread.fp[0]),
 201                                                "m" (p->thread.fpcntl[0])
 202                                              : "memory");
 203                        }
 204                }
 205
 206                /* Restore the state in case the fpu was busy */
 207                asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 208        }
 209#endif /* CONFIG_FPU */
 210
 211        return 0;
 212}
 213
 214/* Fill in the fpu structure for a core dump.  */
 215int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 216{
 217        if (FPU_IS_EMU) {
 218                int i;
 219
 220                memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 221                memcpy(fpu->fpregs, current->thread.fp, 96);
 222                /* Convert internal fpu reg representation
 223                 * into long double format
 224                 */
 225                for (i = 0; i < 24; i += 3)
 226                        fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 227                                         ((fpu->fpregs[i] & 0x0000ffff) << 16);
 228                return 1;
 229        }
 230
 231        if (IS_ENABLED(CONFIG_FPU)) {
 232                char fpustate[216];
 233
 234                /* First dump the fpu context to avoid protocol violation.  */
 235                asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 236                if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 237                        return 0;
 238
 239                if (CPU_IS_COLDFIRE) {
 240                        asm volatile ("fmovel %/fpiar,%0\n\t"
 241                                      "fmovel %/fpcr,%1\n\t"
 242                                      "fmovel %/fpsr,%2\n\t"
 243                                      "fmovemd %/fp0-%/fp7,%3"
 244                                      :
 245                                      : "m" (fpu->fpcntl[0]),
 246                                        "m" (fpu->fpcntl[1]),
 247                                        "m" (fpu->fpcntl[2]),
 248                                        "m" (fpu->fpregs[0])
 249                                      : "memory");
 250                } else {
 251                        asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 252                                      :
 253                                      : "m" (fpu->fpcntl[0])
 254                                      : "memory");
 255                        asm volatile ("fmovemx %/fp0-%/fp7,%0"
 256                                      :
 257                                      : "m" (fpu->fpregs[0])
 258                                      : "memory");
 259                }
 260        }
 261
 262        return 1;
 263}
 264EXPORT_SYMBOL(dump_fpu);
 265
 266unsigned long get_wchan(struct task_struct *p)
 267{
 268        unsigned long fp, pc;
 269        unsigned long stack_page;
 270        int count = 0;
 271        if (!p || p == current || task_is_running(p))
 272                return 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}
 287