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

   1 /* $Id: process.c,v 1.12 2004/12/27 11:18:32 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         regs.dccr = 1 << I_DCCR_BITNR;
 105
 106         /* Ok, create the new process.. */
 107         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 108 }
 109
 110 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
 111  * it will be un-nested during _resume and _ret_from_sys_call when the
 112  * new thread is scheduled.
 113  *
 114  * also setup the thread switching structure which is used to keep
 115  * thread-specific data during _resumes.
 116  *
 117  */
 118 asmlinkage void ret_from_fork(void);
 119
 120 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 121                 unsigned long unused,
 122                 struct task_struct *p, struct pt_regs *regs)
 123 {
 124         struct pt_regs * childregs;
 125         struct switch_stack *swstack;
 126
 127         /* put the pt_regs structure at the end of the new kernel stack page and fix it up
 128          * remember that the task_struct doubles as the kernel stack for the task
 129          */
 130
 131         childregs = user_regs(p->thread_info);
 132
 133         *childregs = *regs;  /* struct copy of pt_regs */
 134
 135         p->set_child_tid = p->clear_child_tid = NULL;
 136
 137         childregs->r10 = 0;  /* child returns 0 after a fork/clone */
 138
 139         /* put the switch stack right below the pt_regs */
 140
 141         swstack = ((struct switch_stack *)childregs) - 1;
 142
 143         swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
 144
 145         /* we want to return into ret_from_sys_call after the _resume */
 146
 147         swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
 148
 149         /* fix the user-mode stackpointer */
 150
 151         p->thread.usp = usp;
 152
 153         /* and the kernel-mode one */
 154
 155         p->thread.ksp = (unsigned long) swstack;
 156
 157 #ifdef DEBUG
 158         printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
 159         show_registers(childregs);
 160 #endif
 161
 162         return 0;
 163 }
 164
 165 /*
 166  * Be aware of the "magic" 7th argument in the four system-calls below.
 167  * They need the latest stackframe, which is put as the 7th argument by
 168  * entry.S. The previous arguments are dummies or actually used, but need
 169  * to be defined to reach the 7th argument.
 170  *
 171  * N.B.: Another method to get the stackframe is to use current_regs(). But
 172  * it returns the latest stack-frame stacked when going from _user mode_ and
 173  * some of these (at least sys_clone) are called from kernel-mode sometimes
 174  * (for example during kernel_thread, above) and thus cannot use it. Thus,
 175  * to be sure not to get any surprises, we use the method for the other calls
 176  * as well.
 177  */
 178
 179 asmlinkage int sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
 180                         struct pt_regs *regs)
 181 {
 182         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 183 }
 184
 185 /* if newusp is 0, we just grab the old usp */
 186 /* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
 187 asmlinkage int sys_clone(unsigned long newusp, unsigned long flags,
 188                          int* parent_tid, int* child_tid, long mof, long srp,
 189                          struct pt_regs *regs)
 190 {
 191         if (!newusp)
 192                 newusp = rdusp();
 193         return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
 194 }
 195
 196 /* vfork is a system call in i386 because of register-pressure - maybe
 197  * we can remove it and handle it in libc but we put it here until then.
 198  */
 199
 200 asmlinkage int sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
 201                          struct pt_regs *regs)
 202 {
 203         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 204 }
 205
 206 /*
 207  * sys_execve() executes a new program.
 208  */
 209 asmlinkage int sys_execve(const char *fname, char **argv, char **envp,
 210                           long r13, long mof, long srp,
 211                           struct pt_regs *regs)
 212 {
 213         int error;
 214         char *filename;
 215
 216         filename = getname(fname);
 217         error = PTR_ERR(filename);
 218
 219         if (IS_ERR(filename))
 220                 goto out;
 221         error = do_execve(filename, argv, envp, regs);
 222         putname(filename);
 223  out:
 224         return error;
 225 }
 226
 227 unsigned long get_wchan(struct task_struct *p)
 228 {
 229 #if 0
 230         /* YURGH. TODO. */
 231
 232         unsigned long ebp, esp, eip;
 233         unsigned long stack_page;
 234         int count = 0;
 235         if (!p || p == current || p->state == TASK_RUNNING)
 236                 return 0;
 237         stack_page = (unsigned long)p;
 238         esp = p->thread.esp;
 239         if (!stack_page || esp < stack_page || esp > 8188+stack_page)
 240                 return 0;
 241         /* include/asm-i386/system.h:switch_to() pushes ebp last. */
 242         ebp = *(unsigned long *) esp;
 243         do {
 244                 if (ebp < stack_page || ebp > 8184+stack_page)
 245                         return 0;
 246                 eip = *(unsigned long *) (ebp+4);
 247                 if (!in_sched_functions(eip))
 248                         return eip;
 249                 ebp = *(unsigned long *) ebp;
 250         } while (count++ < 16);
 251 #endif
 252         return 0;
 253 }
 254 #undef last_sched
 255 #undef first_sched
 256
 257 void show_regs(struct pt_regs * regs)
 258 {
 259         unsigned long usp = rdusp();
 260         printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
 261                regs->irp, regs->srp, regs->dccr, usp, regs->mof );
 262         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 263                regs->r0, regs->r1, regs->r2, regs->r3);
 264         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 265                regs->r4, regs->r5, regs->r6, regs->r7);
 266         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 267                regs->r8, regs->r9, regs->r10, regs->r11);
 268         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 269                regs->r12, regs->r13, regs->orig_r10);
 270 }
 271