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 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
  73  * it will be un-nested during _resume and _ret_from_sys_call when the
  74  * new thread is scheduled.
  75  *
  76  * also setup the thread switching structure which is used to keep
  77  * thread-specific data during _resumes.
  78  *
  79  */
  80 asmlinkage void ret_from_fork(void);
  81 asmlinkage void ret_from_kernel_thread(void);
  82
  83 int copy_thread(unsigned long clone_flags, unsigned long usp,
  84                 unsigned long arg, struct task_struct *p)
  85 {
  86         struct pt_regs *childregs = task_pt_regs(p);
  87         struct switch_stack *swstack = ((struct switch_stack *)childregs) - 1;
  88
  89         /* put the pt_regs structure at the end of the new kernel stack page and fix it up
  90          * remember that the task_struct doubles as the kernel stack for the task
  91          */
  92
  93         if (unlikely(p->flags & PF_KTHREAD)) {
  94                 memset(swstack, 0,
  95                         sizeof(struct switch_stack) + sizeof(struct pt_regs));
  96                 swstack->r1 = usp;
  97                 swstack->r2 = arg;
  98                 childregs->dccr = 1 << I_DCCR_BITNR;
  99                 swstack->return_ip = (unsigned long) ret_from_kernel_thread;
 100                 p->thread.ksp = (unsigned long) swstack;
 101                 p->thread.usp = 0;
 102                 return 0;
 103         }
 104         *childregs = *current_pt_regs();  /* struct copy of pt_regs */
 105
 106         childregs->r10 = 0;  /* child returns 0 after a fork/clone */
 107
 108         /* put the switch stack right below the pt_regs */
 109
 110         swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
 111
 112         /* we want to return into ret_from_sys_call after the _resume */
 113
 114         swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
 115
 116         /* fix the user-mode stackpointer */
 117
 118         p->thread.usp = usp ?: rdusp();
 119
 120         /* and the kernel-mode one */
 121
 122         p->thread.ksp = (unsigned long) swstack;
 123
 124 #ifdef DEBUG
 125         printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
 126         show_registers(childregs);
 127 #endif
 128
 129         return 0;
 130 }
 131
 132 unsigned long get_wchan(struct task_struct *p)
 133 {
 134 #if 0
 135         /* YURGH. TODO. */
 136
 137         unsigned long ebp, esp, eip;
 138         unsigned long stack_page;
 139         int count = 0;
 140         if (!p || p == current || p->state == TASK_RUNNING)
 141                 return 0;
 142         stack_page = (unsigned long)p;
 143         esp = p->thread.esp;
 144         if (!stack_page || esp < stack_page || esp > 8188+stack_page)
 145                 return 0;
 146         /* include/asm-i386/system.h:switch_to() pushes ebp last. */
 147         ebp = *(unsigned long *) esp;
 148         do {
 149                 if (ebp < stack_page || ebp > 8184+stack_page)
 150                         return 0;
 151                 eip = *(unsigned long *) (ebp+4);
 152                 if (!in_sched_functions(eip))
 153                         return eip;
 154                 ebp = *(unsigned long *) ebp;
 155         } while (count++ < 16);
 156 #endif
 157         return 0;
 158 }
 159 #undef last_sched
 160 #undef first_sched
 161
 162 void show_regs(struct pt_regs * regs)
 163 {
 164         unsigned long usp = rdusp();
 165
 166         show_regs_print_info(KERN_DEFAULT);
 167
 168         printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
 169                regs->irp, regs->srp, regs->dccr, usp, regs->mof );
 170         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 171                regs->r0, regs->r1, regs->r2, regs->r3);
 172         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 173                regs->r4, regs->r5, regs->r6, regs->r7);
 174         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 175                regs->r8, regs->r9, regs->r10, regs->r11);
 176         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 177                regs->r12, regs->r13, regs->orig_r10);
 178 }
 179