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