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/sched/debug.h>
  15 #include <linux/slab.h>
  16 #include <linux/err.h>
  17 #include <linux/fs.h>
  18 #include <arch/svinto.h>
  19 #include <linux/init.h>
  20 #include <arch/system.h>
  21 #include <linux/ptrace.h>
  22
  23 #ifdef CONFIG_ETRAX_GPIO
  24 void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
  25 #endif
  26
  27 /*
  28  * We use this if we don't have any better
  29  * idle routine..
  30  */
  31 void default_idle(void)
  32 {
  33 #ifdef CONFIG_ETRAX_GPIO
  34         etrax_gpio_wake_up_check();
  35 #endif
  36         local_irq_enable();
  37 }
  38
  39 /* if the watchdog is enabled, we can simply disable interrupts and go
  40  * into an eternal loop, and the watchdog will reset the CPU after 0.1s
  41  * if on the other hand the watchdog wasn't enabled, we just enable it and wait
  42  */
  43
  44 void hard_reset_now (void)
  45 {
  46         /*
  47          * Don't declare this variable elsewhere.  We don't want any other
  48          * code to know about it than the watchdog handler in entry.S and
  49          * this code, implementing hard reset through the watchdog.
  50          */
  51 #if defined(CONFIG_ETRAX_WATCHDOG)
  52         extern int cause_of_death;
  53 #endif
  54
  55         printk("*** HARD RESET ***\n");
  56         local_irq_disable();
  57
  58 #if defined(CONFIG_ETRAX_WATCHDOG)
  59         cause_of_death = 0xbedead;
  60 #else
  61         /* Since we dont plan to keep on resetting the watchdog,
  62            the key can be arbitrary hence three */
  63         *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
  64                 IO_STATE(R_WATCHDOG, enable, start);
  65 #endif
  66
  67         while(1) /* waiting for RETRIBUTION! */ ;
  68 }
  69
  70 /*
  71  * Return saved PC of a blocked thread.
  72  */
  73 unsigned long thread_saved_pc(struct task_struct *t)
  74 {
  75         return task_pt_regs(t)->irp;
  76 }
  77
  78 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
  79  * it will be un-nested during _resume and _ret_from_sys_call when the
  80  * new thread is scheduled.
  81  *
  82  * also setup the thread switching structure which is used to keep
  83  * thread-specific data during _resumes.
  84  *
  85  */
  86 asmlinkage void ret_from_fork(void);
  87 asmlinkage void ret_from_kernel_thread(void);
  88
  89 int copy_thread(unsigned long clone_flags, unsigned long usp,
  90                 unsigned long arg, struct task_struct *p)
  91 {
  92         struct pt_regs *childregs = task_pt_regs(p);
  93         struct switch_stack *swstack = ((struct switch_stack *)childregs) - 1;
  94
  95         /* put the pt_regs structure at the end of the new kernel stack page and fix it up
  96          * remember that the task_struct doubles as the kernel stack for the task
  97          */
  98
  99         if (unlikely(p->flags & PF_KTHREAD)) {
 100                 memset(swstack, 0,
 101                         sizeof(struct switch_stack) + sizeof(struct pt_regs));
 102                 swstack->r1 = usp;
 103                 swstack->r2 = arg;
 104                 childregs->dccr = 1 << I_DCCR_BITNR;
 105                 swstack->return_ip = (unsigned long) ret_from_kernel_thread;
 106                 p->thread.ksp = (unsigned long) swstack;
 107                 p->thread.usp = 0;
 108                 return 0;
 109         }
 110         *childregs = *current_pt_regs();  /* struct copy of pt_regs */
 111
 112         childregs->r10 = 0;  /* child returns 0 after a fork/clone */
 113
 114         /* put the switch stack right below the pt_regs */
 115
 116         swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
 117
 118         /* we want to return into ret_from_sys_call after the _resume */
 119
 120         swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
 121
 122         /* fix the user-mode stackpointer */
 123
 124         p->thread.usp = usp ?: rdusp();
 125
 126         /* and the kernel-mode one */
 127
 128         p->thread.ksp = (unsigned long) swstack;
 129
 130 #ifdef DEBUG
 131         printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
 132         show_registers(childregs);
 133 #endif
 134
 135         return 0;
 136 }
 137
 138 unsigned long get_wchan(struct task_struct *p)
 139 {
 140 #if 0
 141         /* YURGH. TODO. */
 142
 143         unsigned long ebp, esp, eip;
 144         unsigned long stack_page;
 145         int count = 0;
 146         if (!p || p == current || p->state == TASK_RUNNING)
 147                 return 0;
 148         stack_page = (unsigned long)p;
 149         esp = p->thread.esp;
 150         if (!stack_page || esp < stack_page || esp > 8188+stack_page)
 151                 return 0;
 152         /* include/asm-i386/system.h:switch_to() pushes ebp last. */
 153         ebp = *(unsigned long *) esp;
 154         do {
 155                 if (ebp < stack_page || ebp > 8184+stack_page)
 156                         return 0;
 157                 eip = *(unsigned long *) (ebp+4);
 158                 if (!in_sched_functions(eip))
 159                         return eip;
 160                 ebp = *(unsigned long *) ebp;
 161         } while (count++ < 16);
 162 #endif
 163         return 0;
 164 }
 165 #undef last_sched
 166 #undef first_sched
 167
 168 void show_regs(struct pt_regs * regs)
 169 {
 170         unsigned long usp = rdusp();
 171
 172         show_regs_print_info(KERN_DEFAULT);
 173
 174         printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
 175                regs->irp, regs->srp, regs->dccr, usp, regs->mof );
 176         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 177                regs->r0, regs->r1, regs->r2, regs->r3);
 178         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 179                regs->r4, regs->r5, regs->r6, regs->r7);
 180         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 181                regs->r8, regs->r9, regs->r10, regs->r11);
 182         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 183                regs->r12, regs->r13, regs->orig_r10);
 184 }
 185