// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/debug.h>
#include <linux/delay.h>
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
#include <linux/ptrace.h>
#include <linux/elfcore.h>

#include <asm/elf.h>
#include <abi/reg_ops.h>

struct cpuinfo_csky cpu_data[NR_CPUS];

#ifdef CONFIG_STACKPROTECTOR
#include <linux/stackprotector.h>
unsigned long __stack_chk_guard __read_mostly;
EXPORT_SYMBOL(__stack_chk_guard);
#endif

asmlinkage void ret_from_fork(void);
asmlinkage void ret_from_kernel_thread(void);

/*
 * Some archs flush debug and FPU info here
 */
void flush_thread(void){}

int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
        u64 clone_flags = args->flags;
        unsigned long usp = args->stack;
        unsigned long tls = args->tls;
        struct switch_stack *childstack;
        struct pt_regs *childregs = task_pt_regs(p);

#ifdef CONFIG_CPU_HAS_FPU
        save_to_user_fp(&p->thread.user_fp);
#endif

        childstack = ((struct switch_stack *) childregs) - 1;
        memset(childstack, 0, sizeof(struct switch_stack));

        /* setup thread.sp for switch_to !!! */
        p->thread.sp = (unsigned long)childstack;

        if (unlikely(args->fn)) {
                memset(childregs, 0, sizeof(struct pt_regs));
                childstack->r15 = (unsigned long) ret_from_kernel_thread;
                childstack->r10 = (unsigned long) args->fn_arg;
                childstack->r9 = (unsigned long) args->fn;
                childregs->sr = mfcr("psr");
        } else {
                *childregs = *(current_pt_regs());
                if (usp)
                        childregs->usp = usp;
                if (clone_flags & CLONE_SETTLS)
                        task_thread_info(p)->tp_value = childregs->tls
                                                      = tls;

                childregs->a0 = 0;
                childstack->r15 = (unsigned long) ret_from_fork;
        }

        return 0;
}

/* Fill in the fpu structure for a core dump.  */
int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
{
        memcpy(fpu, &current->thread.user_fp, sizeof(*fpu));
        return 1;
}

int dump_task_regs(struct task_struct *tsk, elf_gregset_t *pr_regs)
{
        struct pt_regs *regs = task_pt_regs(tsk);

        /* NOTE: usp is error value. */
        ELF_CORE_COPY_REGS((*pr_regs), regs)

        return 1;
}

#ifndef CONFIG_CPU_PM_NONE
void arch_cpu_idle(void)
{
#ifdef CONFIG_CPU_PM_WAIT
        asm volatile("wait\n");
#endif

#ifdef CONFIG_CPU_PM_DOZE
        asm volatile("doze\n");
#endif

#ifdef CONFIG_CPU_PM_STOP
        asm volatile("stop\n");
#endif
}
#endif