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

   1 /*
   2  *  linux/arch/cris/kernel/process.c
   3  *
   4  *  Copyright (C) 1995  Linus Torvalds
   5  *  Copyright (C) 2000-2002  Axis Communications AB
   6  *
   7  *  Authors:   Bjorn Wesen (bjornw@axis.com)
   8  *             Mikael Starvik (starvik@axis.com)
   9  *
  10  * This file handles the architecture-dependent parts of process handling..
  11  */
  12
  13 #include <linux/sched.h>
  14 #include <linux/slab.h>
  15 #include <linux/err.h>
  16 #include <linux/fs.h>
  17 #include <arch/svinto.h>
  18 #include <linux/init.h>
  19 #include <arch/system.h>
  20 #include <linux/ptrace.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         local_irq_enable();
  36 }
  37
  38 /* if the watchdog is enabled, we can simply disable interrupts and go
  39  * into an eternal loop, and the watchdog will reset the CPU after 0.1s
  40  * if on the other hand the watchdog wasn't enabled, we just enable it and wait
  41  */
  42
  43 void hard_reset_now (void)
  44 {
  45         /*
  46          * Don't declare this variable elsewhere.  We don't want any other
  47          * code to know about it than the watchdog handler in entry.S and
  48          * this code, implementing hard reset through the watchdog.
  49          */
  50 #if defined(CONFIG_ETRAX_WATCHDOG)
  51         extern int cause_of_death;
  52 #endif
  53
  54         printk("*** HARD RESET ***\n");
  55         local_irq_disable();
  56
  57 #if defined(CONFIG_ETRAX_WATCHDOG)
  58         cause_of_death = 0xbedead;
  59 #else
  60         /* Since we dont plan to keep on resetting the watchdog,
  61            the key can be arbitrary hence three */
  62         *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
  63                 IO_STATE(R_WATCHDOG, enable, start);
  64 #endif
  65
  66         while(1) /* waiting for RETRIBUTION! */ ;
  67 }
  68
  69 /*
  70  * Return saved PC of a blocked thread.
  71  */
  72 unsigned long thread_saved_pc(struct task_struct *t)
  73 {
  74         return task_pt_regs(t)->irp;
  75 }
  76
  77 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
  78  * it will be un-nested during _resume and _ret_from_sys_call when the
  79  * new thread is scheduled.
  80  *
  81  * also setup the thread switching structure which is used to keep
  82  * thread-specific data during _resumes.
  83  *
  84  */
  85 asmlinkage void ret_from_fork(void);
  86 asmlinkage void ret_from_kernel_thread(void);
  87
  88 int copy_thread(unsigned long clone_flags, unsigned long usp,
  89                 unsigned long arg, struct task_struct *p)
  90 {
  91         struct pt_regs *childregs = task_pt_regs(p);
  92         struct switch_stack *swstack = ((struct switch_stack *)childregs) - 1;
  93
  94         /* put the pt_regs structure at the end of the new kernel stack page and fix it up
  95          * remember that the task_struct doubles as the kernel stack for the task
  96          */
  97
  98         if (unlikely(p->flags & PF_KTHREAD)) {
  99                 memset(swstack, 0,
 100                         sizeof(struct switch_stack) + sizeof(struct pt_regs));
 101                 swstack->r1 = usp;
 102                 swstack->r2 = arg;
 103                 childregs->dccr = 1 << I_DCCR_BITNR;
 104                 swstack->return_ip = (unsigned long) ret_from_kernel_thread;
 105                 p->thread.ksp = (unsigned long) swstack;
 106                 p->thread.usp = 0;
 107                 return 0;
 108         }
 109         *childregs = *current_pt_regs();  /* struct copy of pt_regs */
 110
 111         childregs->r10 = 0;  /* child returns 0 after a fork/clone */
 112
 113         /* put the switch stack right below the pt_regs */
 114
 115         swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
 116
 117         /* we want to return into ret_from_sys_call after the _resume */
 118
 119         swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
 120
 121         /* fix the user-mode stackpointer */
 122
 123         p->thread.usp = usp ?: rdusp();
 124
 125         /* and the kernel-mode one */
 126
 127         p->thread.ksp = (unsigned long) swstack;
 128
 129 #ifdef DEBUG
 130         printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
 131         show_registers(childregs);
 132 #endif
 133
 134         return 0;
 135 }
 136
 137 unsigned long get_wchan(struct task_struct *p)
 138 {
 139 #if 0
 140         /* YURGH. TODO. */
 141
 142         unsigned long ebp, esp, eip;
 143         unsigned long stack_page;
 144         int count = 0;
 145         if (!p || p == current || p->state == TASK_RUNNING)
 146                 return 0;
 147         stack_page = (unsigned long)p;
 148         esp = p->thread.esp;
 149         if (!stack_page || esp < stack_page || esp > 8188+stack_page)
 150                 return 0;
 151         /* include/asm-i386/system.h:switch_to() pushes ebp last. */
 152         ebp = *(unsigned long *) esp;
 153         do {
 154                 if (ebp < stack_page || ebp > 8184+stack_page)
 155                         return 0;
 156                 eip = *(unsigned long *) (ebp+4);
 157                 if (!in_sched_functions(eip))
 158                         return eip;
 159                 ebp = *(unsigned long *) ebp;
 160         } while (count++ < 16);
 161 #endif
 162         return 0;
 163 }
 164 #undef last_sched
 165 #undef first_sched
 166
 167 void show_regs(struct pt_regs * regs)
 168 {
 169         unsigned long usp = rdusp();
 170
 171         show_regs_print_info(KERN_DEFAULT);
 172
 173         printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
 174                regs->irp, regs->srp, regs->dccr, usp, regs->mof );
 175         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 176                regs->r0, regs->r1, regs->r2, regs->r3);
 177         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 178                regs->r4, regs->r5, regs->r6, regs->r7);
 179         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 180                regs->r8, regs->r9, regs->r10, regs->r11);
 181         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 182                regs->r12, regs->r13, regs->orig_r10);
 183 }
 184