linux/arch/cris/arch-v32/kernel/process.c
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   1/*
   2 *  Copyright (C) 2000-2003  Axis Communications AB
   3 *
   4 *  Authors:   Bjorn Wesen (bjornw@axis.com)
   5 *             Mikael Starvik (starvik@axis.com)
   6 *             Tobias Anderberg (tobiasa@axis.com), CRISv32 port.
   7 *
   8 * This file handles the architecture-dependent parts of process handling..
   9 */
  10
  11#include <linux/sched.h>
  12#include <linux/slab.h>
  13#include <linux/err.h>
  14#include <linux/fs.h>
  15#include <hwregs/reg_rdwr.h>
  16#include <hwregs/reg_map.h>
  17#include <hwregs/timer_defs.h>
  18#include <hwregs/intr_vect_defs.h>
  19#include <linux/ptrace.h>
  20
  21extern void stop_watchdog(void);
  22
  23extern int cris_hlt_counter;
  24
  25/* We use this if we don't have any better idle routine. */
  26void default_idle(void)
  27{
  28        local_irq_disable();
  29        if (!need_resched() && !cris_hlt_counter) {
  30                /* Halt until exception. */
  31                __asm__ volatile("ei    \n\t"
  32                                 "halt      ");
  33        }
  34        local_irq_enable();
  35}
  36
  37/*
  38 * Free current thread data structures etc..
  39 */
  40
  41extern void deconfigure_bp(long pid);
  42void exit_thread(void)
  43{
  44        deconfigure_bp(current->pid);
  45}
  46
  47/*
  48 * If the watchdog is enabled, disable interrupts and enter an infinite loop.
  49 * The watchdog will reset the CPU after 0.1s. If the watchdog isn't enabled
  50 * then enable it and wait.
  51 */
  52extern void arch_enable_nmi(void);
  53
  54void
  55hard_reset_now(void)
  56{
  57        /*
  58         * Don't declare this variable elsewhere.  We don't want any other
  59         * code to know about it than the watchdog handler in entry.S and
  60         * this code, implementing hard reset through the watchdog.
  61         */
  62#if defined(CONFIG_ETRAX_WATCHDOG)
  63        extern int cause_of_death;
  64#endif
  65
  66        printk("*** HARD RESET ***\n");
  67        local_irq_disable();
  68
  69#if defined(CONFIG_ETRAX_WATCHDOG)
  70        cause_of_death = 0xbedead;
  71#else
  72{
  73        reg_timer_rw_wd_ctrl wd_ctrl = {0};
  74
  75        stop_watchdog();
  76
  77        wd_ctrl.key = 16;       /* Arbitrary key. */
  78        wd_ctrl.cnt = 1;        /* Minimum time. */
  79        wd_ctrl.cmd = regk_timer_start;
  80
  81        arch_enable_nmi();
  82        REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
  83}
  84#endif
  85
  86        while (1)
  87                ; /* Wait for reset. */
  88}
  89
  90/*
  91 * Return saved PC of a blocked thread.
  92 */
  93unsigned long thread_saved_pc(struct task_struct *t)
  94{
  95        return task_pt_regs(t)->erp;
  96}
  97
  98/*
  99 * Setup the child's kernel stack with a pt_regs and call switch_stack() on it.
 100 * It will be unnested during _resume and _ret_from_sys_call when the new thread
 101 * is scheduled.
 102 *
 103 * Also setup the thread switching structure which is used to keep
 104 * thread-specific data during _resumes.
 105 */
 106
 107extern asmlinkage void ret_from_fork(void);
 108extern asmlinkage void ret_from_kernel_thread(void);
 109
 110int
 111copy_thread(unsigned long clone_flags, unsigned long usp,
 112        unsigned long arg, struct task_struct *p)
 113{
 114        struct pt_regs *childregs = task_pt_regs(p);
 115        struct switch_stack *swstack = ((struct switch_stack *) childregs) - 1;
 116
 117        /*
 118         * Put the pt_regs structure at the end of the new kernel stack page and
 119         * fix it up. Note: the task_struct doubles as the kernel stack for the
 120         * task.
 121         */
 122        if (unlikely(p->flags & PF_KTHREAD)) {
 123                memset(swstack, 0,
 124                        sizeof(struct switch_stack) + sizeof(struct pt_regs));
 125                swstack->r1 = usp;
 126                swstack->r2 = arg;
 127                childregs->ccs = 1 << (I_CCS_BITNR + CCS_SHIFT);
 128                swstack->return_ip = (unsigned long) ret_from_kernel_thread;
 129                p->thread.ksp = (unsigned long) swstack;
 130                p->thread.usp = 0;
 131                return 0;
 132        }
 133        *childregs = *current_pt_regs();        /* Struct copy of pt_regs. */
 134        childregs->r10 = 0;     /* Child returns 0 after a fork/clone. */
 135
 136        /* Set a new TLS ?
 137         * The TLS is in $mof because it is the 5th argument to sys_clone.
 138         */
 139        if (p->mm && (clone_flags & CLONE_SETTLS)) {
 140                task_thread_info(p)->tls = childregs->mof;
 141        }
 142
 143        /* Put the switch stack right below the pt_regs. */
 144
 145        /* Parameter to ret_from_sys_call. 0 is don't restart the syscall. */
 146        swstack->r9 = 0;
 147
 148        /*
 149         * We want to return into ret_from_sys_call after the _resume.
 150         * ret_from_fork will call ret_from_sys_call.
 151         */
 152        swstack->return_ip = (unsigned long) ret_from_fork;
 153
 154        /* Fix the user-mode and kernel-mode stackpointer. */
 155        p->thread.usp = usp ?: rdusp();
 156        p->thread.ksp = (unsigned long) swstack;
 157
 158        return 0;
 159}
 160
 161unsigned long
 162get_wchan(struct task_struct *p)
 163{
 164        /* TODO */
 165        return 0;
 166}
 167#undef last_sched
 168#undef first_sched
 169
 170void show_regs(struct pt_regs * regs)
 171{
 172        unsigned long usp = rdusp();
 173        printk("ERP: %08lx SRP: %08lx  CCS: %08lx USP: %08lx MOF: %08lx\n",
 174                regs->erp, regs->srp, regs->ccs, usp, regs->mof);
 175
 176        printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 177                regs->r0, regs->r1, regs->r2, regs->r3);
 178
 179        printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 180                regs->r4, regs->r5, regs->r6, regs->r7);
 181
 182        printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 183                regs->r8, regs->r9, regs->r10, regs->r11);
 184
 185        printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 186                regs->r12, regs->r13, regs->orig_r10);
 187}
 188