arch/cris/arch-v10/kernel/process.c

   1 /* $Id: process.c,v 1.9 2004/10/19 13:07:37 starvik Exp $
   2  *
   3  *  linux/arch/cris/kernel/process.c
   4  *
   5  *  Copyright (C) 1995  Linus Torvalds
   6  *  Copyright (C) 2000-2002  Axis Communications AB
   7  *
   8  *  Authors:   Bjorn Wesen (bjornw@axis.com)
   9  *             Mikael Starvik (starvik@axis.com)
  10  *
  11  * This file handles the architecture-dependent parts of process handling..
  12  */
  13
  14 #include <linux/config.h>
  15 #include <linux/sched.h>
  16 #include <linux/err.h>
  17 #include <linux/fs.h>
  18 #include <linux/slab.h>
  19 #include <asm/arch/svinto.h>
  20 #include <linux/init.h>
  21
  22 #ifdef CONFIG_ETRAX_GPIO
  23 void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
  24 #endif
  25
  26 /*
  27  * We use this if we don't have any better
  28  * idle routine..
  29  */
  30 void default_idle(void)
  31 {
  32 #ifdef CONFIG_ETRAX_GPIO
  33   etrax_gpio_wake_up_check();
  34 #endif
  35 }
  36
  37 /*
  38  * Free current thread data structures etc..
  39  */
  40
  41 void exit_thread(void)
  42 {
  43         /* Nothing needs to be done.  */
  44 }
  45
  46 /* if the watchdog is enabled, we can simply disable interrupts and go
  47  * into an eternal loop, and the watchdog will reset the CPU after 0.1s
  48  * if on the other hand the watchdog wasn't enabled, we just enable it and wait
  49  */
  50
  51 void hard_reset_now (void)
  52 {
  53         /*
  54          * Don't declare this variable elsewhere.  We don't want any other
  55          * code to know about it than the watchdog handler in entry.S and
  56          * this code, implementing hard reset through the watchdog.
  57          */
  58 #if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
  59         extern int cause_of_death;
  60 #endif
  61
  62         printk("*** HARD RESET ***\n");
  63         local_irq_disable();
  64
  65 #if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
  66         cause_of_death = 0xbedead;
  67 #else
  68         /* Since we dont plan to keep on reseting the watchdog,
  69            the key can be arbitrary hence three */
  70         *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
  71                 IO_STATE(R_WATCHDOG, enable, start);
  72 #endif
  73
  74         while(1) /* waiting for RETRIBUTION! */ ;
  75 }
  76
  77 /*
  78  * Return saved PC of a blocked thread.
  79  */
  80 unsigned long thread_saved_pc(struct task_struct *t)
  81 {
  82         return (unsigned long)user_regs(t->thread_info)->irp;
  83 }
  84
  85 static void kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
  86 {
  87   fn(arg);
  88   do_exit(-1); /* Should never be called, return bad exit value */
  89 }
  90
  91 /*
  92  * Create a kernel thread
  93  */
  94 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
  95 {
  96         struct pt_regs regs;
  97
  98         memset(&regs, 0, sizeof(regs));
  99
 100         /* Don't use r10 since that is set to 0 in copy_thread */
 101         regs.r11 = (unsigned long)fn;
 102         regs.r12 = (unsigned long)arg;
 103         regs.irp = (unsigned long)kernel_thread_helper;
 104
 105         /* Ok, create the new process.. */
 106         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 107 }
 108
 109 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
 110  * it will be un-nested during _resume and _ret_from_sys_call when the
 111  * new thread is scheduled.
 112  *
 113  * also setup the thread switching structure which is used to keep
 114  * thread-specific data during _resumes.
 115  *
 116  */
 117 asmlinkage void ret_from_fork(void);
 118
 119 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 120                 unsigned long unused,
 121                 struct task_struct *p, struct pt_regs *regs)
 122 {
 123         struct pt_regs * childregs;
 124         struct switch_stack *swstack;
 125
 126         /* put the pt_regs structure at the end of the new kernel stack page and fix it up
 127          * remember that the task_struct doubles as the kernel stack for the task
 128          */
 129
 130         childregs = user_regs(p->thread_info);
 131
 132         *childregs = *regs;  /* struct copy of pt_regs */
 133
 134         p->set_child_tid = p->clear_child_tid = NULL;
 135
 136         childregs->r10 = 0;  /* child returns 0 after a fork/clone */
 137
 138         /* put the switch stack right below the pt_regs */
 139
 140         swstack = ((struct switch_stack *)childregs) - 1;
 141
 142         swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
 143
 144         /* we want to return into ret_from_sys_call after the _resume */
 145
 146         swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
 147
 148         /* fix the user-mode stackpointer */
 149
 150         p->thread.usp = usp;
 151
 152         /* and the kernel-mode one */
 153
 154         p->thread.ksp = (unsigned long) swstack;
 155
 156 #ifdef DEBUG
 157         printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
 158         show_registers(childregs);
 159 #endif
 160
 161         return 0;
 162 }
 163
 164 /*
 165  * Be aware of the "magic" 7th argument in the four system-calls below.
 166  * They need the latest stackframe, which is put as the 7th argument by
 167  * entry.S. The previous arguments are dummies or actually used, but need
 168  * to be defined to reach the 7th argument.
 169  *
 170  * N.B.: Another method to get the stackframe is to use current_regs(). But
 171  * it returns the latest stack-frame stacked when going from _user mode_ and
 172  * some of these (at least sys_clone) are called from kernel-mode sometimes
 173  * (for example during kernel_thread, above) and thus cannot use it. Thus,
 174  * to be sure not to get any surprises, we use the method for the other calls
 175  * as well.
 176  */
 177
 178 asmlinkage int sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
 179                         struct pt_regs *regs)
 180 {
 181         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 182 }
 183
 184 /* if newusp is 0, we just grab the old usp */
 185 /* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
 186 asmlinkage int sys_clone(unsigned long newusp, unsigned long flags,
 187                          int* parent_tid, int* child_tid, long mof, long srp,
 188                          struct pt_regs *regs)
 189 {
 190         if (!newusp)
 191                 newusp = rdusp();
 192         return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
 193 }
 194
 195 /* vfork is a system call in i386 because of register-pressure - maybe
 196  * we can remove it and handle it in libc but we put it here until then.
 197  */
 198
 199 asmlinkage int sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
 200                          struct pt_regs *regs)
 201 {
 202         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 203 }
 204
 205 /*
 206  * sys_execve() executes a new program.
 207  */
 208 asmlinkage int sys_execve(const char *fname, char **argv, char **envp,
 209                           long r13, long mof, long srp,
 210                           struct pt_regs *regs)
 211 {
 212         int error;
 213         char *filename;
 214
 215         filename = getname(fname);
 216         error = PTR_ERR(filename);
 217
 218         if (IS_ERR(filename))
 219                 goto out;
 220         error = do_execve(filename, argv, envp, regs);
 221         putname(filename);
 222  out:
 223         return error;
 224 }
 225
 226 unsigned long get_wchan(struct task_struct *p)
 227 {
 228 #if 0
 229         /* YURGH. TODO. */
 230
 231         unsigned long ebp, esp, eip;
 232         unsigned long stack_page;
 233         int count = 0;
 234         if (!p || p == current || p->state == TASK_RUNNING)
 235                 return 0;
 236         stack_page = (unsigned long)p;
 237         esp = p->thread.esp;
 238         if (!stack_page || esp < stack_page || esp > 8188+stack_page)
 239                 return 0;
 240         /* include/asm-i386/system.h:switch_to() pushes ebp last. */
 241         ebp = *(unsigned long *) esp;
 242         do {
 243                 if (ebp < stack_page || ebp > 8184+stack_page)
 244                         return 0;
 245                 eip = *(unsigned long *) (ebp+4);
 246                 if (!in_sched_functions(eip))
 247                         return eip;
 248                 ebp = *(unsigned long *) ebp;
 249         } while (count++ < 16);
 250 #endif
 251         return 0;
 252 }
 253 #undef last_sched
 254 #undef first_sched
 255
 256 void show_regs(struct pt_regs * regs)
 257 {
 258         unsigned long usp = rdusp();
 259         printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
 260                regs->irp, regs->srp, regs->dccr, usp, regs->mof );
 261         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 262                regs->r0, regs->r1, regs->r2, regs->r3);
 263         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 264                regs->r4, regs->r5, regs->r6, regs->r7);
 265         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 266                regs->r8, regs->r9, regs->r10, regs->r11);
 267         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 268                regs->r12, regs->r13, regs->orig_r10);
 269 }
 270