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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Copyright (C) 2000-2003  Axis Communications AB
   4  *
   5  *  Authors:   Bjorn Wesen (bjornw@axis.com)
   6  *             Mikael Starvik (starvik@axis.com)
   7  *             Tobias Anderberg (tobiasa@axis.com), CRISv32 port.
   8  *
   9  * This file handles the architecture-dependent parts of process handling..
  10  */
  11
  12 #include <linux/sched.h>
  13 #include <linux/sched/debug.h>
  14 #include <linux/sched/task.h>
  15 #include <linux/sched/task_stack.h>
  16 #include <linux/slab.h>
  17 #include <linux/err.h>
  18 #include <linux/fs.h>
  19 #include <hwregs/reg_rdwr.h>
  20 #include <hwregs/reg_map.h>
  21 #include <hwregs/timer_defs.h>
  22 #include <hwregs/intr_vect_defs.h>
  23 #include <linux/ptrace.h>
  24
  25 extern void stop_watchdog(void);
  26
  27 /* We use this if we don't have any better idle routine. */
  28 void default_idle(void)
  29 {
  30         local_irq_enable();
  31         /* Halt until exception. */
  32         __asm__ volatile("halt");
  33 }
  34
  35 /*
  36  * Free current thread data structures etc..
  37  */
  38
  39 extern void deconfigure_bp(long pid);
  40 void exit_thread(struct task_struct *tsk)
  41 {
  42         deconfigure_bp(tsk->pid);
  43 }
  44
  45 /*
  46  * If the watchdog is enabled, disable interrupts and enter an infinite loop.
  47  * The watchdog will reset the CPU after 0.1s. If the watchdog isn't enabled
  48  * then enable it and wait.
  49  */
  50 extern void arch_enable_nmi(void);
  51
  52 void
  53 hard_reset_now(void)
  54 {
  55         /*
  56          * Don't declare this variable elsewhere.  We don't want any other
  57          * code to know about it than the watchdog handler in entry.S and
  58          * this code, implementing hard reset through the watchdog.
  59          */
  60 #if defined(CONFIG_ETRAX_WATCHDOG)
  61         extern int cause_of_death;
  62 #endif
  63
  64         printk("*** HARD RESET ***\n");
  65         local_irq_disable();
  66
  67 #if defined(CONFIG_ETRAX_WATCHDOG)
  68         cause_of_death = 0xbedead;
  69 #else
  70 {
  71         reg_timer_rw_wd_ctrl wd_ctrl = {0};
  72
  73         stop_watchdog();
  74
  75         wd_ctrl.key = 16;       /* Arbitrary key. */
  76         wd_ctrl.cnt = 1;        /* Minimum time. */
  77         wd_ctrl.cmd = regk_timer_start;
  78
  79         arch_enable_nmi();
  80         REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
  81 }
  82 #endif
  83
  84         while (1)
  85                 ; /* Wait for reset. */
  86 }
  87
  88 /*
  89  * Setup the child's kernel stack with a pt_regs and call switch_stack() on it.
  90  * It will be unnested during _resume and _ret_from_sys_call when the new thread
  91  * is scheduled.
  92  *
  93  * Also setup the thread switching structure which is used to keep
  94  * thread-specific data during _resumes.
  95  */
  96
  97 extern asmlinkage void ret_from_fork(void);
  98 extern asmlinkage void ret_from_kernel_thread(void);
  99
 100 int
 101 copy_thread(unsigned long clone_flags, unsigned long usp,
 102         unsigned long arg, struct task_struct *p)
 103 {
 104         struct pt_regs *childregs = task_pt_regs(p);
 105         struct switch_stack *swstack = ((struct switch_stack *) childregs) - 1;
 106
 107         /*
 108          * Put the pt_regs structure at the end of the new kernel stack page and
 109          * fix it up. Note: the task_struct doubles as the kernel stack for the
 110          * task.
 111          */
 112         if (unlikely(p->flags & PF_KTHREAD)) {
 113                 memset(swstack, 0,
 114                         sizeof(struct switch_stack) + sizeof(struct pt_regs));
 115                 swstack->r1 = usp;
 116                 swstack->r2 = arg;
 117                 childregs->ccs = 1 << (I_CCS_BITNR + CCS_SHIFT);
 118                 swstack->return_ip = (unsigned long) ret_from_kernel_thread;
 119                 p->thread.ksp = (unsigned long) swstack;
 120                 p->thread.usp = 0;
 121                 return 0;
 122         }
 123         *childregs = *current_pt_regs();        /* Struct copy of pt_regs. */
 124         childregs->r10 = 0;     /* Child returns 0 after a fork/clone. */
 125
 126         /* Set a new TLS ?
 127          * The TLS is in $mof because it is the 5th argument to sys_clone.
 128          */
 129         if (p->mm && (clone_flags & CLONE_SETTLS)) {
 130                 task_thread_info(p)->tls = childregs->mof;
 131         }
 132
 133         /* Put the switch stack right below the pt_regs. */
 134
 135         /* Parameter to ret_from_sys_call. 0 is don't restart the syscall. */
 136         swstack->r9 = 0;
 137
 138         /*
 139          * We want to return into ret_from_sys_call after the _resume.
 140          * ret_from_fork will call ret_from_sys_call.
 141          */
 142         swstack->return_ip = (unsigned long) ret_from_fork;
 143
 144         /* Fix the user-mode and kernel-mode stackpointer. */
 145         p->thread.usp = usp ?: rdusp();
 146         p->thread.ksp = (unsigned long) swstack;
 147
 148         return 0;
 149 }
 150
 151 unsigned long
 152 get_wchan(struct task_struct *p)
 153 {
 154         /* TODO */
 155         return 0;
 156 }
 157 #undef last_sched
 158 #undef first_sched
 159
 160 void show_regs(struct pt_regs * regs)
 161 {
 162         unsigned long usp = rdusp();
 163
 164         show_regs_print_info(KERN_DEFAULT);
 165
 166         printk("ERP: %08lx SRP: %08lx  CCS: %08lx USP: %08lx MOF: %08lx\n",
 167                 regs->erp, regs->srp, regs->ccs, usp, regs->mof);
 168
 169         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 170                 regs->r0, regs->r1, regs->r2, regs->r3);
 171
 172         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 173                 regs->r4, regs->r5, regs->r6, regs->r7);
 174
 175         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 176                 regs->r8, regs->r9, regs->r10, regs->r11);
 177
 178         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 179                 regs->r12, regs->r13, regs->orig_r10);
 180 }