// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */
#include <linux/init.h>
#include <linux/export.h>
#include <linux/mm.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>

struct page *dmw_virt_to_page(unsigned long kaddr)
{
        return phys_to_page(__pa(kaddr));
}
EXPORT_SYMBOL(dmw_virt_to_page);

struct page *tlb_virt_to_page(unsigned long kaddr)
{
        return phys_to_page(pfn_to_phys(pte_pfn(*virt_to_kpte(kaddr))));
}
EXPORT_SYMBOL(tlb_virt_to_page);

pgd_t *pgd_alloc(struct mm_struct *mm)
{
        pgd_t *init, *ret;

        ret = __pgd_alloc(mm, 0);
        if (ret) {
                init = pgd_offset(&init_mm, 0UL);
                pgd_init(ret);
                memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
                       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
        }

        return ret;
}
EXPORT_SYMBOL_GPL(pgd_alloc);

void pgd_init(void *addr)
{
        unsigned long *p, *end;
        unsigned long entry;

#if !defined(__PAGETABLE_PUD_FOLDED)
        entry = (unsigned long)invalid_pud_table;
#elif !defined(__PAGETABLE_PMD_FOLDED)
        entry = (unsigned long)invalid_pmd_table;
#else
        entry = (unsigned long)invalid_pte_table;
#endif

        p = (unsigned long *)addr;
        end = p + PTRS_PER_PGD;

        do {
                p[0] = entry;
                p[1] = entry;
                p[2] = entry;
                p[3] = entry;
                p[4] = entry;
                p += 8;
                p[-3] = entry;
                p[-2] = entry;
                p[-1] = entry;
        } while (p != end);
}
EXPORT_SYMBOL_GPL(pgd_init);

#ifndef __PAGETABLE_PMD_FOLDED
void pmd_init(void *addr)
{
        unsigned long *p, *end;
        unsigned long pagetable = (unsigned long)invalid_pte_table;

        p = (unsigned long *)addr;
        end = p + PTRS_PER_PMD;

        do {
                p[0] = pagetable;
                p[1] = pagetable;
                p[2] = pagetable;
                p[3] = pagetable;
                p[4] = pagetable;
                p += 8;
                p[-3] = pagetable;
                p[-2] = pagetable;
                p[-1] = pagetable;
        } while (p != end);
}
EXPORT_SYMBOL_GPL(pmd_init);
#endif

#ifndef __PAGETABLE_PUD_FOLDED
void pud_init(void *addr)
{
        unsigned long *p, *end;
        unsigned long pagetable = (unsigned long)invalid_pmd_table;

        p = (unsigned long *)addr;
        end = p + PTRS_PER_PUD;

        do {
                p[0] = pagetable;
                p[1] = pagetable;
                p[2] = pagetable;
                p[3] = pagetable;
                p[4] = pagetable;
                p += 8;
                p[-3] = pagetable;
                p[-2] = pagetable;
                p[-1] = pagetable;
        } while (p != end);
}
EXPORT_SYMBOL_GPL(pud_init);
#endif

void kernel_pte_init(void *addr)
{
        unsigned long *p, *end;

        p = (unsigned long *)addr;
        end = p + PTRS_PER_PTE;

        do {
                p[0] = _PAGE_GLOBAL;
                p[1] = _PAGE_GLOBAL;
                p[2] = _PAGE_GLOBAL;
                p[3] = _PAGE_GLOBAL;
                p[4] = _PAGE_GLOBAL;
                p += 8;
                p[-3] = _PAGE_GLOBAL;
                p[-2] = _PAGE_GLOBAL;
                p[-1] = _PAGE_GLOBAL;
        } while (p != end);
}

void set_pmd_at(struct mm_struct *mm, unsigned long addr,
                pmd_t *pmdp, pmd_t pmd)
{
        WRITE_ONCE(*pmdp, pmd);
        flush_tlb_all();
}

void __init pagetable_init(void)
{
        /* Initialize the entire pgd.  */
        pgd_init(swapper_pg_dir);
        pgd_init(invalid_pg_dir);
#ifndef __PAGETABLE_PUD_FOLDED
        pud_init(invalid_pud_table);
#endif
#ifndef __PAGETABLE_PMD_FOLDED
        pmd_init(invalid_pmd_table);
#endif
}