LXR linux/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
  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 * 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 */
 115asmlinkage 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
 122int 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.  */
 196int 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}
 245EXPORT_SYMBOL(dump_fpu);
 246
 247unsigned 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}
 268