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