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/sched/task.h>
  16 #include <linux/sched/task_stack.h>
  17 #include <linux/slab.h>
  18 #include <linux/err.h>
  19 #include <linux/fs.h>
  20 #include <arch/svinto.h>
  21 #include <linux/init.h>
  22 #include <arch/system.h>
  23 #include <linux/ptrace.h>
  24
  25 #ifdef CONFIG_ETRAX_GPIO
  26 void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
  27 #endif
  28
  29 /*
  30  * We use this if we don't have any better
  31  * idle routine..
  32  */
  33 void default_idle(void)
  34 {
  35 #ifdef CONFIG_ETRAX_GPIO
  36         etrax_gpio_wake_up_check();
  37 #endif
  38         local_irq_enable();
  39 }
  40
  41 /* if the watchdog is enabled, we can simply disable interrupts and go
  42  * into an eternal loop, and the watchdog will reset the CPU after 0.1s
  43  * if on the other hand the watchdog wasn't enabled, we just enable it and wait
  44  */
  45
  46 void hard_reset_now (void)
  47 {
  48         /*
  49          * Don't declare this variable elsewhere.  We don't want any other
  50          * code to know about it than the watchdog handler in entry.S and
  51          * this code, implementing hard reset through the watchdog.
  52          */
  53 #if defined(CONFIG_ETRAX_WATCHDOG)
  54         extern int cause_of_death;
  55 #endif
  56
  57         printk("*** HARD RESET ***\n");
  58         local_irq_disable();
  59
  60 #if defined(CONFIG_ETRAX_WATCHDOG)
  61         cause_of_death = 0xbedead;
  62 #else
  63         /* Since we dont plan to keep on resetting the watchdog,
  64            the key can be arbitrary hence three */
  65         *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
  66                 IO_STATE(R_WATCHDOG, enable, start);
  67 #endif
  68
  69         while(1) /* waiting for RETRIBUTION! */ ;
  70 }
  71
  72 /*
  73  * Return saved PC of a blocked thread.
  74  */
  75 unsigned long thread_saved_pc(struct task_struct *t)
  76 {
  77         return task_pt_regs(t)->irp;
  78 }
  79
  80 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
  81  * it will be un-nested during _resume and _ret_from_sys_call when the
  82  * new thread is scheduled.
  83  *
  84  * also setup the thread switching structure which is used to keep
  85  * thread-specific data during _resumes.
  86  *
  87  */
  88 asmlinkage void ret_from_fork(void);
  89 asmlinkage void ret_from_kernel_thread(void);
  90
  91 int copy_thread(unsigned long clone_flags, unsigned long usp,
  92                 unsigned long arg, struct task_struct *p)
  93 {
  94         struct pt_regs *childregs = task_pt_regs(p);
  95         struct switch_stack *swstack = ((struct switch_stack *)childregs) - 1;
  96
  97         /* put the pt_regs structure at the end of the new kernel stack page and fix it up
  98          * remember that the task_struct doubles as the kernel stack for the task
  99          */
 100
 101         if (unlikely(p->flags & PF_KTHREAD)) {
 102                 memset(swstack, 0,
 103                         sizeof(struct switch_stack) + sizeof(struct pt_regs));
 104                 swstack->r1 = usp;
 105                 swstack->r2 = arg;
 106                 childregs->dccr = 1 << I_DCCR_BITNR;
 107                 swstack->return_ip = (unsigned long) ret_from_kernel_thread;
 108                 p->thread.ksp = (unsigned long) swstack;
 109                 p->thread.usp = 0;
 110                 return 0;
 111         }
 112         *childregs = *current_pt_regs();  /* struct copy of pt_regs */
 113
 114         childregs->r10 = 0;  /* child returns 0 after a fork/clone */
 115
 116         /* put the switch stack right below the pt_regs */
 117
 118         swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
 119
 120         /* we want to return into ret_from_sys_call after the _resume */
 121
 122         swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
 123
 124         /* fix the user-mode stackpointer */
 125
 126         p->thread.usp = usp ?: rdusp();
 127
 128         /* and the kernel-mode one */
 129
 130         p->thread.ksp = (unsigned long) swstack;
 131
 132 #ifdef DEBUG
 133         printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
 134         show_registers(childregs);
 135 #endif
 136
 137         return 0;
 138 }
 139
 140 unsigned long get_wchan(struct task_struct *p)
 141 {
 142 #if 0
 143         /* YURGH. TODO. */
 144
 145         unsigned long ebp, esp, eip;
 146         unsigned long stack_page;
 147         int count = 0;
 148         if (!p || p == current || p->state == TASK_RUNNING)
 149                 return 0;
 150         stack_page = (unsigned long)p;
 151         esp = p->thread.esp;
 152         if (!stack_page || esp < stack_page || esp > 8188+stack_page)
 153                 return 0;
 154         /* include/asm-i386/system.h:switch_to() pushes ebp last. */
 155         ebp = *(unsigned long *) esp;
 156         do {
 157                 if (ebp < stack_page || ebp > 8184+stack_page)
 158                         return 0;
 159                 eip = *(unsigned long *) (ebp+4);
 160                 if (!in_sched_functions(eip))
 161                         return eip;
 162                 ebp = *(unsigned long *) ebp;
 163         } while (count++ < 16);
 164 #endif
 165         return 0;
 166 }
 167 #undef last_sched
 168 #undef first_sched
 169
 170 void show_regs(struct pt_regs * regs)
 171 {
 172         unsigned long usp = rdusp();
 173
 174         show_regs_print_info(KERN_DEFAULT);
 175
 176         printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
 177                regs->irp, regs->srp, regs->dccr, usp, regs->mof );
 178         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 179                regs->r0, regs->r1, regs->r2, regs->r3);
 180         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 181                regs->r4, regs->r5, regs->r6, regs->r7);
 182         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 183                regs->r8, regs->r9, regs->r10, regs->r11);
 184         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 185                regs->r12, regs->r13, regs->orig_r10);
 186 }
 187