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(unsigned long clone_flags,
  38                 unsigned long usp,
  39                 unsigned long kthread_arg,
  40                 struct task_struct *p)
  41 {
  42         struct switch_stack *childstack;
  43         struct pt_regs *childregs = task_pt_regs(p);
  44
  45 #ifdef CONFIG_CPU_HAS_FPU
  46         save_to_user_fp(&p->thread.user_fp);
  47 #endif
  48
  49         childstack = ((struct switch_stack *) childregs) - 1;
  50         memset(childstack, 0, sizeof(struct switch_stack));
  51
  52         /* setup ksp for switch_to !!! */
  53         p->thread.ksp = (unsigned long)childstack;
  54
  55         if (unlikely(p->flags & PF_KTHREAD)) {
  56                 memset(childregs, 0, sizeof(struct pt_regs));
  57                 childstack->r15 = (unsigned long) ret_from_kernel_thread;
  58                 childstack->r8 = kthread_arg;
  59                 childstack->r9 = usp;
  60                 childregs->sr = mfcr("psr");
  61         } else {
  62                 *childregs = *(current_pt_regs());
  63                 if (usp)
  64                         childregs->usp = usp;
  65                 if (clone_flags & CLONE_SETTLS)
  66                         task_thread_info(p)->tp_value = childregs->tls
  67                                                       = childregs->regs[0];
  68
  69                 childregs->a0 = 0;
  70                 childstack->r15 = (unsigned long) ret_from_fork;
  71         }
  72
  73         return 0;
  74 }
  75
  76 /* Fill in the fpu structure for a core dump.  */
  77 int dump_fpu(struct pt_regs *regs, struct user_fp *fpu)
  78 {
  79         memcpy(fpu, &current->thread.user_fp, sizeof(*fpu));
  80         return 1;
  81 }
  82 EXPORT_SYMBOL(dump_fpu);
  83
  84 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *pr_regs)
  85 {
  86         struct pt_regs *regs = task_pt_regs(tsk);
  87
  88         /* NOTE: usp is error value. */
  89         ELF_CORE_COPY_REGS((*pr_regs), regs)
  90
  91         return 1;
  92 }
  93
  94 unsigned long get_wchan(struct task_struct *p)
  95 {
  96         unsigned long lr;
  97         unsigned long *fp, *stack_start, *stack_end;
  98         int count = 0;
  99
 100         if (!p || p == current || p->state == TASK_RUNNING)
 101                 return 0;
 102
 103         stack_start = (unsigned long *)end_of_stack(p);
 104         stack_end = (unsigned long *)(task_stack_page(p) + THREAD_SIZE);
 105
 106         fp = (unsigned long *) thread_saved_fp(p);
 107         do {
 108                 if (fp < stack_start || fp > stack_end)
 109                         return 0;
 110 #ifdef CONFIG_STACKTRACE
 111                 lr = fp[1];
 112                 fp = (unsigned long *)fp[0];
 113 #else
 114                 lr = *fp++;
 115 #endif
 116                 if (!in_sched_functions(lr) &&
 117                     __kernel_text_address(lr))
 118                         return lr;
 119         } while (count++ < 16);
 120
 121         return 0;
 122 }
 123 EXPORT_SYMBOL(get_wchan);
 124
 125 #ifndef CONFIG_CPU_PM_NONE
 126 void arch_cpu_idle(void)
 127 {
 128 #ifdef CONFIG_CPU_PM_WAIT
 129         asm volatile("wait\n");
 130 #endif
 131
 132 #ifdef CONFIG_CPU_PM_DOZE
 133         asm volatile("doze\n");
 134 #endif
 135
 136 #ifdef CONFIG_CPU_PM_STOP
 137         asm volatile("stop\n");
 138 #endif
 139         local_irq_enable();
 140 }
 141 #endif