// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */

#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/err.h>
#include <linux/sysctl.h>
#include <asm/mman.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>

pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
                      unsigned long addr, unsigned long sz)
{
        pgd_t *pgd;
        p4d_t *p4d;
        pud_t *pud;
        pte_t *pte = NULL;

        pgd = pgd_offset(mm, addr);
        p4d = p4d_alloc(mm, pgd, addr);
        pud = pud_alloc(mm, p4d, addr);
        if (pud)
                pte = (pte_t *)pmd_alloc(mm, pud, addr);

        return pte;
}

pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr,
                       unsigned long sz)
{
        pgd_t *pgd;
        p4d_t *p4d;
        pud_t *pud;
        pmd_t *pmd = NULL;

        pgd = pgd_offset(mm, addr);
        if (pgd_present(pgdp_get(pgd))) {
                p4d = p4d_offset(pgd, addr);
                if (p4d_present(p4dp_get(p4d))) {
                        pud = pud_offset(p4d, addr);
                        if (pud_present(pudp_get(pud)))
                                pmd = pmd_offset(pud, addr);
                }
        }

        return (!pmd || pmd_none(pmdp_get(pmd))) ? NULL : (pte_t *) pmd;
}

uint64_t pmd_to_entrylo(unsigned long pmd_val)
{
        uint64_t val;
        /* PMD as PTE. Must be huge page */
        if (!pmd_leaf(__pmd(pmd_val)))
                panic("%s", __func__);

        val = pmd_val ^ _PAGE_HUGE;
        val |= ((val & _PAGE_HGLOBAL) >>
                (_PAGE_HGLOBAL_SHIFT - _PAGE_GLOBAL_SHIFT));

        return val;
}