arch/h8300/kernel/process.c

   1 /*
   2  *  linux/arch/h8300/kernel/process.c
   3  *
   4  * Yoshinori Sato <ysato@users.sourceforge.jp>
   5  *
   6  *  Based on:
   7  *
   8  *  linux/arch/m68knommu/kernel/process.c
   9  *
  10  *  Copyright (C) 1998  D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>,
  11  *                      Kenneth Albanowski <kjahds@kjahds.com>,
  12  *                      The Silver Hammer Group, Ltd.
  13  *
  14  *  linux/arch/m68k/kernel/process.c
  15  *
  16  *  Copyright (C) 1995  Hamish Macdonald
  17  *
  18  *  68060 fixes by Jesper Skov
  19  */
  20
  21 /*
  22  * This file handles the architecture-dependent parts of process handling..
  23  */
  24
  25 #include <linux/errno.h>
  26 #include <linux/module.h>
  27 #include <linux/sched.h>
  28 #include <linux/kernel.h>
  29 #include <linux/mm.h>
  30 #include <linux/smp.h>
  31 #include <linux/stddef.h>
  32 #include <linux/unistd.h>
  33 #include <linux/ptrace.h>
  34 #include <linux/user.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/reboot.h>
  37 #include <linux/fs.h>
  38 #include <linux/slab.h>
  39
  40 #include <asm/uaccess.h>
  41 #include <asm/system.h>
  42 #include <asm/traps.h>
  43 #include <asm/setup.h>
  44 #include <asm/pgtable.h>
  45
  46 void (*pm_power_off)(void) = NULL;
  47 EXPORT_SYMBOL(pm_power_off);
  48
  49 asmlinkage void ret_from_fork(void);
  50
  51 /*
  52  * The idle loop on an H8/300..
  53  */
  54 #if !defined(CONFIG_H8300H_SIM) && !defined(CONFIG_H8S_SIM)
  55 static void default_idle(void)
  56 {
  57         local_irq_disable();
  58         if (!need_resched()) {
  59                 local_irq_enable();
  60                 /* XXX: race here! What if need_resched() gets set now? */
  61                 __asm__("sleep");
  62         } else
  63                 local_irq_enable();
  64 }
  65 #else
  66 static void default_idle(void)
  67 {
  68         cpu_relax();
  69 }
  70 #endif
  71 void (*idle)(void) = default_idle;
  72
  73 /*
  74  * The idle thread. There's no useful work to be
  75  * done, so just try to conserve power and have a
  76  * low exit latency (ie sit in a loop waiting for
  77  * somebody to say that they'd like to reschedule)
  78  */
  79 void cpu_idle(void)
  80 {
  81         while (1) {
  82                 while (!need_resched())
  83                         idle();
  84                 preempt_enable_no_resched();
  85                 schedule();
  86                 preempt_disable();
  87         }
  88 }
  89
  90 void machine_restart(char * __unused)
  91 {
  92         local_irq_disable();
  93         __asm__("jmp @@0");
  94 }
  95
  96 void machine_halt(void)
  97 {
  98         local_irq_disable();
  99         __asm__("sleep");
 100         for (;;);
 101 }
 102
 103 void machine_power_off(void)
 104 {
 105         local_irq_disable();
 106         __asm__("sleep");
 107         for (;;);
 108 }
 109
 110 void show_regs(struct pt_regs * regs)
 111 {
 112         printk("\nPC: %08lx  Status: %02x",
 113                regs->pc, regs->ccr);
 114         printk("\nORIG_ER0: %08lx ER0: %08lx ER1: %08lx",
 115                regs->orig_er0, regs->er0, regs->er1);
 116         printk("\nER2: %08lx ER3: %08lx ER4: %08lx ER5: %08lx",
 117                regs->er2, regs->er3, regs->er4, regs->er5);
 118         printk("\nER6' %08lx ",regs->er6);
 119         if (user_mode(regs))
 120                 printk("USP: %08lx\n", rdusp());
 121         else
 122                 printk("\n");
 123 }
 124
 125 /*
 126  * Create a kernel thread
 127  */
 128 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 129 {
 130         long retval;
 131         long clone_arg;
 132         mm_segment_t fs;
 133
 134         fs = get_fs();
 135         set_fs (KERNEL_DS);
 136         clone_arg = flags | CLONE_VM;
 137         __asm__("mov.l sp,er3\n\t"
 138                 "sub.l er2,er2\n\t"
 139                 "mov.l %2,er1\n\t"
 140                 "mov.l %1,er0\n\t"
 141                 "trapa #0\n\t"
 142                 "cmp.l sp,er3\n\t"
 143                 "beq 1f\n\t"
 144                 "mov.l %4,er0\n\t"
 145                 "mov.l %3,er1\n\t"
 146                 "jsr @er1\n\t"
 147                 "mov.l %5,er0\n\t"
 148                 "trapa #0\n"
 149                 "1:\n\t"
 150                 "mov.l er0,%0"
 151                 :"=r"(retval)
 152                 :"i"(__NR_clone),"g"(clone_arg),"g"(fn),"g"(arg),"i"(__NR_exit)
 153                 :"er0","er1","er2","er3");
 154         set_fs (fs);
 155         return retval;
 156 }
 157
 158 void flush_thread(void)
 159 {
 160 }
 161
 162 /*
 163  * "h8300_fork()".. By the time we get here, the
 164  * non-volatile registers have also been saved on the
 165  * stack. We do some ugly pointer stuff here.. (see
 166  * also copy_thread)
 167  */
 168
 169 asmlinkage int h8300_fork(struct pt_regs *regs)
 170 {
 171         return -EINVAL;
 172 }
 173
 174 asmlinkage int h8300_vfork(struct pt_regs *regs)
 175 {
 176         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 177 }
 178
 179 asmlinkage int h8300_clone(struct pt_regs *regs)
 180 {
 181         unsigned long clone_flags;
 182         unsigned long newsp;
 183
 184         /* syscall2 puts clone_flags in er1 and usp in er2 */
 185         clone_flags = regs->er1;
 186         newsp = regs->er2;
 187         if (!newsp)
 188                 newsp  = rdusp();
 189         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 190
 191 }
 192
 193 int copy_thread(unsigned long clone_flags,
 194                 unsigned long usp, unsigned long topstk,
 195                  struct task_struct * p, struct pt_regs * regs)
 196 {
 197         struct pt_regs * childregs;
 198
 199         childregs = (struct pt_regs *) (THREAD_SIZE + task_stack_page(p)) - 1;
 200
 201         *childregs = *regs;
 202         childregs->retpc = (unsigned long) ret_from_fork;
 203         childregs->er0 = 0;
 204
 205         p->thread.usp = usp;
 206         p->thread.ksp = (unsigned long)childregs;
 207
 208         return 0;
 209 }
 210
 211 /*
 212  * sys_execve() executes a new program.
 213  */
 214 asmlinkage int sys_execve(const char *name,
 215                           const char *const *argv,
 216                           const char *const *envp,
 217                           int dummy, ...)
 218 {
 219         int error;
 220         char * filename;
 221         struct pt_regs *regs = (struct pt_regs *) ((unsigned char *)&dummy-4);
 222
 223         filename = getname(name);
 224         error = PTR_ERR(filename);
 225         if (IS_ERR(filename))
 226                 return error;
 227         error = do_execve(filename, argv, envp, regs);
 228         putname(filename);
 229         return error;
 230 }
 231
 232 unsigned long thread_saved_pc(struct task_struct *tsk)
 233 {
 234         return ((struct pt_regs *)tsk->thread.esp0)->pc;
 235 }
 236
 237 unsigned long get_wchan(struct task_struct *p)
 238 {
 239         unsigned long fp, pc;
 240         unsigned long stack_page;
 241         int count = 0;
 242         if (!p || p == current || p->state == TASK_RUNNING)
 243                 return 0;
 244
 245         stack_page = (unsigned long)p;
 246         fp = ((struct pt_regs *)p->thread.ksp)->er6;
 247         do {
 248                 if (fp < stack_page+sizeof(struct thread_info) ||
 249                     fp >= 8184+stack_page)
 250                         return 0;
 251                 pc = ((unsigned long *)fp)[1];
 252                 if (!in_sched_functions(pc))
 253                         return pc;
 254                 fp = *(unsigned long *) fp;
 255         } while (count++ < 16);
 256         return 0;
 257 }