LXR linux/arch/m68k/kernel/process.c

   1/*
   2 *  linux/arch/m68k/kernel/process.c
   3 *
   4 *  Copyright (C) 1995  Hamish Macdonald
   5 *
   6 *  68060 fixes by Jesper Skov
   7 */
   8
   9/*
  10 * This file handles the architecture-dependent parts of process handling..
  11 */
  12
  13#include <linux/errno.h>
  14#include <linux/module.h>
  15#include <linux/sched.h>
  16#include <linux/sched/debug.h>
  17#include <linux/sched/task.h>
  18#include <linux/sched/task_stack.h>
  19#include <linux/kernel.h>
  20#include <linux/mm.h>
  21#include <linux/slab.h>
  22#include <linux/fs.h>
  23#include <linux/smp.h>
  24#include <linux/stddef.h>
  25#include <linux/unistd.h>
  26#include <linux/ptrace.h>
  27#include <linux/user.h>
  28#include <linux/reboot.h>
  29#include <linux/init_task.h>
  30#include <linux/mqueue.h>
  31#include <linux/rcupdate.h>
  32
  33#include <linux/uaccess.h>
  34#include <asm/traps.h>
  35#include <asm/machdep.h>
  36#include <asm/setup.h>
  37#include <asm/pgtable.h>
  38
  39
  40asmlinkage void ret_from_fork(void);
  41asmlinkage void ret_from_kernel_thread(void);
  42
  43void arch_cpu_idle(void)
  44{
  45#if defined(MACH_ATARI_ONLY)
  46        /* block out HSYNC on the atari (falcon) */
  47        __asm__("stop #0x2200" : : : "cc");
  48#else
  49        __asm__("stop #0x2000" : : : "cc");
  50#endif
  51}
  52
  53void machine_restart(char * __unused)
  54{
  55        if (mach_reset)
  56                mach_reset();
  57        for (;;);
  58}
  59
  60void machine_halt(void)
  61{
  62        if (mach_halt)
  63                mach_halt();
  64        for (;;);
  65}
  66
  67void machine_power_off(void)
  68{
  69        if (mach_power_off)
  70                mach_power_off();
  71        for (;;);
  72}
  73
  74void (*pm_power_off)(void) = machine_power_off;
  75EXPORT_SYMBOL(pm_power_off);
  76
  77void 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
  92void flush_thread(void)
  93{
  94        current->thread.fs = __USER_DS;
  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 * do_fork() anyway.  So in this case it's actually better to pass pt_regs *
 110 * and extract arguments for do_fork() from there.  Eventually we might
 111 * go for calling do_fork() directly from the wrapper, but only after we
 112 * are finished with do_fork() prototype conversion.
 113 */
 114asmlinkage int m68k_clone(struct pt_regs *regs)
 115{
 116        /* regs will be equal to current_pt_regs() */
 117        return do_fork(regs->d1, regs->d2, 0,
 118                       (int __user *)regs->d3, (int __user *)regs->d4);
 119}
 120
 121int copy_thread(unsigned long clone_flags, unsigned long usp,
 122                 unsigned long arg, struct task_struct *p)
 123{
 124        struct fork_frame {
 125                struct switch_stack sw;
 126                struct pt_regs regs;
 127        } *frame;
 128
 129        frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
 130
 131        p->thread.ksp = (unsigned long)frame;
 132        p->thread.esp0 = (unsigned long)&frame->regs;
 133
 134        /*
 135         * Must save the current SFC/DFC value, NOT the value when
 136         * the parent was last descheduled - RGH  10-08-96
 137         */
 138        p->thread.fs = get_fs().seg;
 139
 140        if (unlikely(p->flags & PF_KTHREAD)) {
 141                /* kernel thread */
 142                memset(frame, 0, sizeof(struct fork_frame));
 143                frame->regs.sr = PS_S;
 144                frame->sw.a3 = usp; /* function */
 145                frame->sw.d7 = arg;
 146                frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
 147                p->thread.usp = 0;
 148                return 0;
 149        }
 150        memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
 151                sizeof(struct fork_frame));
 152        frame->regs.d0 = 0;
 153        frame->sw.retpc = (unsigned long)ret_from_fork;
 154        p->thread.usp = usp ?: rdusp();
 155
 156        if (clone_flags & CLONE_SETTLS)
 157                task_thread_info(p)->tp_value = frame->regs.d5;
 158
 159#ifdef CONFIG_FPU
 160        if (!FPU_IS_EMU) {
 161                /* Copy the current fpu state */
 162                asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 163
 164                if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
 165                        if (CPU_IS_COLDFIRE) {
 166                                asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
 167                                              "fmovel %/fpiar,%1\n\t"
 168                                              "fmovel %/fpcr,%2\n\t"
 169                                              "fmovel %/fpsr,%3"
 170                                              :
 171                                              : "m" (p->thread.fp[0]),
 172                                                "m" (p->thread.fpcntl[0]),
 173                                                "m" (p->thread.fpcntl[1]),
 174                                                "m" (p->thread.fpcntl[2])
 175                                              : "memory");
 176                        } else {
 177                                asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 178                                              "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 179                                              :
 180                                              : "m" (p->thread.fp[0]),
 181                                                "m" (p->thread.fpcntl[0])
 182                                              : "memory");
 183                        }
 184                }
 185
 186                /* Restore the state in case the fpu was busy */
 187                asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 188        }
 189#endif /* CONFIG_FPU */
 190
 191        return 0;
 192}
 193
 194/* Fill in the fpu structure for a core dump.  */
 195int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 196{
 197        if (FPU_IS_EMU) {
 198                int i;
 199
 200                memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 201                memcpy(fpu->fpregs, current->thread.fp, 96);
 202                /* Convert internal fpu reg representation
 203                 * into long double format
 204                 */
 205                for (i = 0; i < 24; i += 3)
 206                        fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 207                                         ((fpu->fpregs[i] & 0x0000ffff) << 16);
 208                return 1;
 209        }
 210
 211        if (IS_ENABLED(CONFIG_FPU)) {
 212                char fpustate[216];
 213
 214                /* First dump the fpu context to avoid protocol violation.  */
 215                asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 216                if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 217                        return 0;
 218
 219                if (CPU_IS_COLDFIRE) {
 220                        asm volatile ("fmovel %/fpiar,%0\n\t"
 221                                      "fmovel %/fpcr,%1\n\t"
 222                                      "fmovel %/fpsr,%2\n\t"
 223                                      "fmovemd %/fp0-%/fp7,%3"
 224                                      :
 225                                      : "m" (fpu->fpcntl[0]),
 226                                        "m" (fpu->fpcntl[1]),
 227                                        "m" (fpu->fpcntl[2]),
 228                                        "m" (fpu->fpregs[0])
 229                                      : "memory");
 230                } else {
 231                        asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 232                                      :
 233                                      : "m" (fpu->fpcntl[0])
 234                                      : "memory");
 235                        asm volatile ("fmovemx %/fp0-%/fp7,%0"
 236                                      :
 237                                      : "m" (fpu->fpregs[0])
 238                                      : "memory");
 239                }
 240        }
 241
 242        return 1;
 243}
 244EXPORT_SYMBOL(dump_fpu);
 245
 246unsigned long get_wchan(struct task_struct *p)
 247{
 248        unsigned long fp, pc;
 249        unsigned long stack_page;
 250        int count = 0;
 251        if (!p || p == current || p->state == TASK_RUNNING)
 252                return 0;
 253
 254        stack_page = (unsigned long)task_stack_page(p);
 255        fp = ((struct switch_stack *)p->thread.ksp)->a6;
 256        do {
 257                if (fp < stack_page+sizeof(struct thread_info) ||
 258                    fp >= 8184+stack_page)
 259                        return 0;
 260                pc = ((unsigned long *)fp)[1];
 261                if (!in_sched_functions(pc))
 262                        return pc;
 263                fp = *(unsigned long *) fp;
 264        } while (count++ < 16);
 265        return 0;
 266}
 267