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 #ifdef CONFIG_STACKPROTECTOR
  20 #include <linux/stackprotector.h>
  21 unsigned long __stack_chk_guard __read_mostly;
  22 EXPORT_SYMBOL(__stack_chk_guard);
  23 #endif
  24
  25 asmlinkage void ret_from_fork(void);
  26 asmlinkage void ret_from_kernel_thread(void);
  27
  28 /*
  29  * Some archs flush debug and FPU info here
  30  */
  31 void flush_thread(void){}
  32
  33 /*
  34  * Return saved PC from a blocked thread
  35  */
  36 unsigned long thread_saved_pc(struct task_struct *tsk)
  37 {
  38         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  39
  40         return sw->r15;
  41 }
  42
  43 int copy_thread_tls(unsigned long clone_flags,
  44                 unsigned long usp,
  45                 unsigned long kthread_arg,
  46                 struct task_struct *p,
  47                 unsigned long tls)
  48 {
  49         struct switch_stack *childstack;
  50         struct pt_regs *childregs = task_pt_regs(p);
  51
  52 #ifdef CONFIG_CPU_HAS_FPU
  53         save_to_user_fp(&p->thread.user_fp);
  54 #endif
  55
  56         childstack = ((struct switch_stack *) childregs) - 1;
  57         memset(childstack, 0, sizeof(struct switch_stack));
  58
  59         /* setup ksp for switch_to !!! */
  60         p->thread.ksp = (unsigned long)childstack;
  61
  62         if (unlikely(p->flags & PF_KTHREAD)) {
  63                 memset(childregs, 0, sizeof(struct pt_regs));
  64                 childstack->r15 = (unsigned long) ret_from_kernel_thread;
  65                 childstack->r10 = kthread_arg;
  66                 childstack->r9 = usp;
  67                 childregs->sr = mfcr("psr");
  68         } else {
  69                 *childregs = *(current_pt_regs());
  70                 if (usp)
  71                         childregs->usp = usp;
  72                 if (clone_flags & CLONE_SETTLS)
  73                         task_thread_info(p)->tp_value = childregs->tls
  74                                                       = tls;
  75
  76                 childregs->a0 = 0;
  77                 childstack->r15 = (unsigned long) ret_from_fork;
  78         }
  79
  80         return 0;
  81 }
  82
  83 /* Fill in the fpu structure for a core dump.  */
  84 int dump_fpu(struct pt_regs *regs, struct user_fp *fpu)
  85 {
  86         memcpy(fpu, &current->thread.user_fp, sizeof(*fpu));
  87         return 1;
  88 }
  89 EXPORT_SYMBOL(dump_fpu);
  90
  91 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *pr_regs)
  92 {
  93         struct pt_regs *regs = task_pt_regs(tsk);
  94
  95         /* NOTE: usp is error value. */
  96         ELF_CORE_COPY_REGS((*pr_regs), regs)
  97
  98         return 1;
  99 }
 100
 101 unsigned long get_wchan(struct task_struct *p)
 102 {
 103         unsigned long lr;
 104         unsigned long *fp, *stack_start, *stack_end;
 105         int count = 0;
 106
 107         if (!p || p == current || p->state == TASK_RUNNING)
 108                 return 0;
 109
 110         stack_start = (unsigned long *)end_of_stack(p);
 111         stack_end = (unsigned long *)(task_stack_page(p) + THREAD_SIZE);
 112
 113         fp = (unsigned long *) thread_saved_fp(p);
 114         do {
 115                 if (fp < stack_start || fp > stack_end)
 116                         return 0;
 117 #ifdef CONFIG_STACKTRACE
 118                 lr = fp[1];
 119                 fp = (unsigned long *)fp[0];
 120 #else
 121                 lr = *fp++;
 122 #endif
 123                 if (!in_sched_functions(lr) &&
 124                     __kernel_text_address(lr))
 125                         return lr;
 126         } while (count++ < 16);
 127
 128         return 0;
 129 }
 130 EXPORT_SYMBOL(get_wchan);
 131
 132 #ifndef CONFIG_CPU_PM_NONE
 133 void arch_cpu_idle(void)
 134 {
 135 #ifdef CONFIG_CPU_PM_WAIT
 136         asm volatile("wait\n");
 137 #endif
 138
 139 #ifdef CONFIG_CPU_PM_DOZE
 140         asm volatile("doze\n");
 141 #endif
 142
 143 #ifdef CONFIG_CPU_PM_STOP
 144         asm volatile("stop\n");
 145 #endif
 146         local_irq_enable();
 147 }
 148 #endif