arch/csky/kernel/process.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
   3
   4 #include <linux/module.h>
   5 #include <linux/version.h>
   6 #include <linux/sched.h>
   7 #include <linux/sched/task_stack.h>
   8 #include <linux/sched/debug.h>
   9 #include <linux/delay.h>
  10 #include <linux/kallsyms.h>
  11 #include <linux/uaccess.h>
  12 #include <linux/ptrace.h>
  13
  14 #include <asm/elf.h>
  15 #include <abi/reg_ops.h>
  16
  17 struct cpuinfo_csky cpu_data[NR_CPUS];
  18
  19 asmlinkage void ret_from_fork(void);
  20 asmlinkage void ret_from_kernel_thread(void);
  21
  22 /*
  23  * Some archs flush debug and FPU info here
  24  */
  25 void flush_thread(void){}
  26
  27 /*
  28  * Return saved PC from a blocked thread
  29  */
  30 unsigned long thread_saved_pc(struct task_struct *tsk)
  31 {
  32         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  33
  34         return sw->r15;
  35 }
  36
  37 int copy_thread_tls(unsigned long clone_flags,
  38                 unsigned long usp,
  39                 unsigned long kthread_arg,
  40                 struct task_struct *p,
  41                 unsigned long tls)
  42 {
  43         struct switch_stack *childstack;
  44         struct pt_regs *childregs = task_pt_regs(p);
  45
  46 #ifdef CONFIG_CPU_HAS_FPU
  47         save_to_user_fp(&p->thread.user_fp);
  48 #endif
  49
  50         childstack = ((struct switch_stack *) childregs) - 1;
  51         memset(childstack, 0, sizeof(struct switch_stack));
  52
  53         /* setup ksp for switch_to !!! */
  54         p->thread.ksp = (unsigned long)childstack;
  55
  56         if (unlikely(p->flags & PF_KTHREAD)) {
  57                 memset(childregs, 0, sizeof(struct pt_regs));
  58                 childstack->r15 = (unsigned long) ret_from_kernel_thread;
  59                 childstack->r10 = kthread_arg;
  60                 childstack->r9 = usp;
  61                 childregs->sr = mfcr("psr");
  62         } else {
  63                 *childregs = *(current_pt_regs());
  64                 if (usp)
  65                         childregs->usp = usp;
  66                 if (clone_flags & CLONE_SETTLS)
  67                         task_thread_info(p)->tp_value = childregs->tls
  68                                                       = tls;
  69
  70                 childregs->a0 = 0;
  71                 childstack->r15 = (unsigned long) ret_from_fork;
  72         }
  73
  74         return 0;
  75 }
  76
  77 /* Fill in the fpu structure for a core dump.  */
  78 int dump_fpu(struct pt_regs *regs, struct user_fp *fpu)
  79 {
  80         memcpy(fpu, &current->thread.user_fp, sizeof(*fpu));
  81         return 1;
  82 }
  83 EXPORT_SYMBOL(dump_fpu);
  84
  85 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *pr_regs)
  86 {
  87         struct pt_regs *regs = task_pt_regs(tsk);
  88
  89         /* NOTE: usp is error value. */
  90         ELF_CORE_COPY_REGS((*pr_regs), regs)
  91
  92         return 1;
  93 }
  94
  95 unsigned long get_wchan(struct task_struct *p)
  96 {
  97         unsigned long lr;
  98         unsigned long *fp, *stack_start, *stack_end;
  99         int count = 0;
 100
 101         if (!p || p == current || p->state == TASK_RUNNING)
 102                 return 0;
 103
 104         stack_start = (unsigned long *)end_of_stack(p);
 105         stack_end = (unsigned long *)(task_stack_page(p) + THREAD_SIZE);
 106
 107         fp = (unsigned long *) thread_saved_fp(p);
 108         do {
 109                 if (fp < stack_start || fp > stack_end)
 110                         return 0;
 111 #ifdef CONFIG_STACKTRACE
 112                 lr = fp[1];
 113                 fp = (unsigned long *)fp[0];
 114 #else
 115                 lr = *fp++;
 116 #endif
 117                 if (!in_sched_functions(lr) &&
 118                     __kernel_text_address(lr))
 119                         return lr;
 120         } while (count++ < 16);
 121
 122         return 0;
 123 }
 124 EXPORT_SYMBOL(get_wchan);
 125
 126 #ifndef CONFIG_CPU_PM_NONE
 127 void arch_cpu_idle(void)
 128 {
 129 #ifdef CONFIG_CPU_PM_WAIT
 130         asm volatile("wait\n");
 131 #endif
 132
 133 #ifdef CONFIG_CPU_PM_DOZE
 134         asm volatile("doze\n");
 135 #endif
 136
 137 #ifdef CONFIG_CPU_PM_STOP
 138         asm volatile("stop\n");
 139 #endif
 140         local_irq_enable();
 141 }
 142 #endif