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 /*
  39  * Free current thread data structures etc..
  40  */
  41
  42 void exit_thread(void)
  43 {
  44         /* Nothing needs to be done.  */
  45 }
  46
  47 /* if the watchdog is enabled, we can simply disable interrupts and go
  48  * into an eternal loop, and the watchdog will reset the CPU after 0.1s
  49  * if on the other hand the watchdog wasn't enabled, we just enable it and wait
  50  */
  51
  52 void hard_reset_now (void)
  53 {
  54         /*
  55          * Don't declare this variable elsewhere.  We don't want any other
  56          * code to know about it than the watchdog handler in entry.S and
  57          * this code, implementing hard reset through the watchdog.
  58          */
  59 #if defined(CONFIG_ETRAX_WATCHDOG)
  60         extern int cause_of_death;
  61 #endif
  62
  63         printk("*** HARD RESET ***\n");
  64         local_irq_disable();
  65
  66 #if defined(CONFIG_ETRAX_WATCHDOG)
  67         cause_of_death = 0xbedead;
  68 #else
  69         /* Since we dont plan to keep on resetting the watchdog,
  70            the key can be arbitrary hence three */
  71         *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
  72                 IO_STATE(R_WATCHDOG, enable, start);
  73 #endif
  74
  75         while(1) /* waiting for RETRIBUTION! */ ;
  76 }
  77
  78 /*
  79  * Return saved PC of a blocked thread.
  80  */
  81 unsigned long thread_saved_pc(struct task_struct *t)
  82 {
  83         return task_pt_regs(t)->irp;
  84 }
  85
  86 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
  87  * it will be un-nested during _resume and _ret_from_sys_call when the
  88  * new thread is scheduled.
  89  *
  90  * also setup the thread switching structure which is used to keep
  91  * thread-specific data during _resumes.
  92  *
  93  */
  94 asmlinkage void ret_from_fork(void);
  95 asmlinkage void ret_from_kernel_thread(void);
  96
  97 int copy_thread(unsigned long clone_flags, unsigned long usp,
  98                 unsigned long arg, struct task_struct *p)
  99 {
 100         struct pt_regs *childregs = task_pt_regs(p);
 101         struct switch_stack *swstack = ((struct switch_stack *)childregs) - 1;
 102
 103         /* put the pt_regs structure at the end of the new kernel stack page and fix it up
 104          * remember that the task_struct doubles as the kernel stack for the task
 105          */
 106
 107         if (unlikely(p->flags & PF_KTHREAD)) {
 108                 memset(swstack, 0,
 109                         sizeof(struct switch_stack) + sizeof(struct pt_regs));
 110                 swstack->r1 = usp;
 111                 swstack->r2 = arg;
 112                 childregs->dccr = 1 << I_DCCR_BITNR;
 113                 swstack->return_ip = (unsigned long) ret_from_kernel_thread;
 114                 p->thread.ksp = (unsigned long) swstack;
 115                 p->thread.usp = 0;
 116                 return 0;
 117         }
 118         *childregs = *current_pt_regs();  /* struct copy of pt_regs */
 119
 120         childregs->r10 = 0;  /* child returns 0 after a fork/clone */
 121
 122         /* put the switch stack right below the pt_regs */
 123
 124         swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
 125
 126         /* we want to return into ret_from_sys_call after the _resume */
 127
 128         swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
 129
 130         /* fix the user-mode stackpointer */
 131
 132         p->thread.usp = usp ?: rdusp();
 133
 134         /* and the kernel-mode one */
 135
 136         p->thread.ksp = (unsigned long) swstack;
 137
 138 #ifdef DEBUG
 139         printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
 140         show_registers(childregs);
 141 #endif
 142
 143         return 0;
 144 }
 145
 146 unsigned long get_wchan(struct task_struct *p)
 147 {
 148 #if 0
 149         /* YURGH. TODO. */
 150
 151         unsigned long ebp, esp, eip;
 152         unsigned long stack_page;
 153         int count = 0;
 154         if (!p || p == current || p->state == TASK_RUNNING)
 155                 return 0;
 156         stack_page = (unsigned long)p;
 157         esp = p->thread.esp;
 158         if (!stack_page || esp < stack_page || esp > 8188+stack_page)
 159                 return 0;
 160         /* include/asm-i386/system.h:switch_to() pushes ebp last. */
 161         ebp = *(unsigned long *) esp;
 162         do {
 163                 if (ebp < stack_page || ebp > 8184+stack_page)
 164                         return 0;
 165                 eip = *(unsigned long *) (ebp+4);
 166                 if (!in_sched_functions(eip))
 167                         return eip;
 168                 ebp = *(unsigned long *) ebp;
 169         } while (count++ < 16);
 170 #endif
 171         return 0;
 172 }
 173 #undef last_sched
 174 #undef first_sched
 175
 176 void show_regs(struct pt_regs * regs)
 177 {
 178         unsigned long usp = rdusp();
 179
 180         show_regs_print_info(KERN_DEFAULT);
 181
 182         printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
 183                regs->irp, regs->srp, regs->dccr, usp, regs->mof );
 184         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 185                regs->r0, regs->r1, regs->r2, regs->r3);
 186         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 187                regs->r4, regs->r5, regs->r6, regs->r7);
 188         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 189                regs->r8, regs->r9, regs->r10, regs->r11);
 190         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 191                regs->r12, regs->r13, regs->orig_r10);
 192 }
 193