arch/cris/arch-v10/kernel/process.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/arch/cris/kernel/process.c
   4  *
   5  *  Copyright (C) 1995  Linus Torvalds
   6  *  Copyright (C) 2000-2002  Axis Communications AB
   7  *
   8  *  Authors:   Bjorn Wesen (bjornw@axis.com)
   9  *             Mikael Starvik (starvik@axis.com)
  10  *
  11  * This file handles the architecture-dependent parts of process handling..
  12  */
  13
  14 #include <linux/sched.h>
  15 #include <linux/sched/debug.h>
  16 #include <linux/sched/task.h>
  17 #include <linux/sched/task_stack.h>
  18 #include <linux/slab.h>
  19 #include <linux/err.h>
  20 #include <linux/fs.h>
  21 #include <arch/svinto.h>
  22 #include <linux/init.h>
  23 #include <arch/system.h>
  24 #include <linux/ptrace.h>
  25
  26 #ifdef CONFIG_ETRAX_GPIO
  27 void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
  28 #endif
  29
  30 /*
  31  * We use this if we don't have any better
  32  * idle routine..
  33  */
  34 void default_idle(void)
  35 {
  36 #ifdef CONFIG_ETRAX_GPIO
  37         etrax_gpio_wake_up_check();
  38 #endif
  39         local_irq_enable();
  40 }
  41
  42 /* if the watchdog is enabled, we can simply disable interrupts and go
  43  * into an eternal loop, and the watchdog will reset the CPU after 0.1s
  44  * if on the other hand the watchdog wasn't enabled, we just enable it and wait
  45  */
  46
  47 void hard_reset_now (void)
  48 {
  49         /*
  50          * Don't declare this variable elsewhere.  We don't want any other
  51          * code to know about it than the watchdog handler in entry.S and
  52          * this code, implementing hard reset through the watchdog.
  53          */
  54 #if defined(CONFIG_ETRAX_WATCHDOG)
  55         extern int cause_of_death;
  56 #endif
  57
  58         printk("*** HARD RESET ***\n");
  59         local_irq_disable();
  60
  61 #if defined(CONFIG_ETRAX_WATCHDOG)
  62         cause_of_death = 0xbedead;
  63 #else
  64         /* Since we dont plan to keep on resetting the watchdog,
  65            the key can be arbitrary hence three */
  66         *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
  67                 IO_STATE(R_WATCHDOG, enable, start);
  68 #endif
  69
  70         while(1) /* waiting for RETRIBUTION! */ ;
  71 }
  72
  73 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
  74  * it will be un-nested during _resume and _ret_from_sys_call when the
  75  * new thread is scheduled.
  76  *
  77  * also setup the thread switching structure which is used to keep
  78  * thread-specific data during _resumes.
  79  *
  80  */
  81 asmlinkage void ret_from_fork(void);
  82 asmlinkage void ret_from_kernel_thread(void);
  83
  84 int copy_thread(unsigned long clone_flags, unsigned long usp,
  85                 unsigned long arg, struct task_struct *p)
  86 {
  87         struct pt_regs *childregs = task_pt_regs(p);
  88         struct switch_stack *swstack = ((struct switch_stack *)childregs) - 1;
  89
  90         /* put the pt_regs structure at the end of the new kernel stack page and fix it up
  91          * remember that the task_struct doubles as the kernel stack for the task
  92          */
  93
  94         if (unlikely(p->flags & PF_KTHREAD)) {
  95                 memset(swstack, 0,
  96                         sizeof(struct switch_stack) + sizeof(struct pt_regs));
  97                 swstack->r1 = usp;
  98                 swstack->r2 = arg;
  99                 childregs->dccr = 1 << I_DCCR_BITNR;
 100                 swstack->return_ip = (unsigned long) ret_from_kernel_thread;
 101                 p->thread.ksp = (unsigned long) swstack;
 102                 p->thread.usp = 0;
 103                 return 0;
 104         }
 105         *childregs = *current_pt_regs();  /* struct copy of pt_regs */
 106
 107         childregs->r10 = 0;  /* child returns 0 after a fork/clone */
 108
 109         /* put the switch stack right below the pt_regs */
 110
 111         swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
 112
 113         /* we want to return into ret_from_sys_call after the _resume */
 114
 115         swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
 116
 117         /* fix the user-mode stackpointer */
 118
 119         p->thread.usp = usp ?: rdusp();
 120
 121         /* and the kernel-mode one */
 122
 123         p->thread.ksp = (unsigned long) swstack;
 124
 125 #ifdef DEBUG
 126         printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
 127         show_registers(childregs);
 128 #endif
 129
 130         return 0;
 131 }
 132
 133 unsigned long get_wchan(struct task_struct *p)
 134 {
 135 #if 0
 136         /* YURGH. TODO. */
 137
 138         unsigned long ebp, esp, eip;
 139         unsigned long stack_page;
 140         int count = 0;
 141         if (!p || p == current || p->state == TASK_RUNNING)
 142                 return 0;
 143         stack_page = (unsigned long)p;
 144         esp = p->thread.esp;
 145         if (!stack_page || esp < stack_page || esp > 8188+stack_page)
 146                 return 0;
 147         /* include/asm-i386/system.h:switch_to() pushes ebp last. */
 148         ebp = *(unsigned long *) esp;
 149         do {
 150                 if (ebp < stack_page || ebp > 8184+stack_page)
 151                         return 0;
 152                 eip = *(unsigned long *) (ebp+4);
 153                 if (!in_sched_functions(eip))
 154                         return eip;
 155                 ebp = *(unsigned long *) ebp;
 156         } while (count++ < 16);
 157 #endif
 158         return 0;
 159 }
 160 #undef last_sched
 161 #undef first_sched
 162
 163 void show_regs(struct pt_regs * regs)
 164 {
 165         unsigned long usp = rdusp();
 166
 167         show_regs_print_info(KERN_DEFAULT);
 168
 169         printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
 170                regs->irp, regs->srp, regs->dccr, usp, regs->mof );
 171         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 172                regs->r0, regs->r1, regs->r2, regs->r3);
 173         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 174                regs->r4, regs->r5, regs->r6, regs->r7);
 175         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 176                regs->r8, regs->r9, regs->r10, regs->r11);
 177         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 178                regs->r12, regs->r13, regs->orig_r10);
 179 }
 180