arch/cris/arch-v32/kernel/process.c

   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
  21 extern void stop_watchdog(void);
  22
  23 extern int cris_hlt_counter;
  24
  25 /* We use this if we don't have any better idle routine. */
  26 void 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
  41 extern void deconfigure_bp(long pid);
  42 void 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  */
  52 extern void arch_enable_nmi(void);
  53
  54 void
  55 hard_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  */
  93 unsigned 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
 107 extern asmlinkage void ret_from_fork(void);
 108 extern asmlinkage void ret_from_kernel_thread(void);
 109
 110 int
 111 copy_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
 161 unsigned long
 162 get_wchan(struct task_struct *p)
 163 {
 164         /* TODO */
 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         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 }