// SPDX-License-Identifier: GPL-2.0

#include <asm/pgalloc.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/pgtable.h>

int ptep_set_access_flags(struct vm_area_struct *vma,
                          unsigned long address, pte_t *ptep,
                          pte_t entry, int dirty)
{
        if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SVVPTC)) {
                if (!pte_same(ptep_get(ptep), entry)) {
                        __set_pte_at(vma->vm_mm, ptep, entry);
                        /* Here only not svadu is impacted */
                        flush_tlb_page(vma, address);
                        return true;
                }

                return false;
        }

        if (!pte_same(ptep_get(ptep), entry))
                __set_pte_at(vma->vm_mm, ptep, entry);
        /*
         * update_mmu_cache will unconditionally execute, handling both
         * the case that the PTE changed and the spurious fault case.
         */
        return true;
}

int ptep_test_and_clear_young(struct vm_area_struct *vma,
                              unsigned long address,
                              pte_t *ptep)
{
        if (!pte_young(ptep_get(ptep)))
                return 0;
        return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep));
}
EXPORT_SYMBOL_GPL(ptep_test_and_clear_young);

#ifdef CONFIG_64BIT
pud_t *pud_offset(p4d_t *p4d, unsigned long address)
{
        if (pgtable_l4_enabled)
                return p4d_pgtable(p4dp_get(p4d)) + pud_index(address);

        return (pud_t *)p4d;
}
EXPORT_SYMBOL_GPL(pud_offset);

p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
{
        if (pgtable_l5_enabled)
                return pgd_pgtable(pgdp_get(pgd)) + p4d_index(address);

        return (p4d_t *)pgd;
}
EXPORT_SYMBOL_GPL(p4d_offset);
#endif

#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
{
        return 0;
}

void p4d_clear_huge(p4d_t *p4d)
{
}

int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
{
        pud_t new_pud = pfn_pud(__phys_to_pfn(phys), prot);

        set_pud(pud, new_pud);
        return 1;
}

int pud_clear_huge(pud_t *pud)
{
        if (!pud_leaf(pudp_get(pud)))
                return 0;
        pud_clear(pud);
        return 1;
}

int pud_free_pmd_page(pud_t *pud, unsigned long addr)
{
        pmd_t *pmd = pud_pgtable(pudp_get(pud));
        int i;

        pud_clear(pud);

        flush_tlb_kernel_range(addr, addr + PUD_SIZE);

        for (i = 0; i < PTRS_PER_PMD; i++) {
                if (!pmd_none(pmd[i])) {
                        pte_t *pte = (pte_t *)pmd_page_vaddr(pmd[i]);

                        pte_free_kernel(NULL, pte);
                }
        }

        pmd_free(NULL, pmd);

        return 1;
}

int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
{
        pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), prot);

        set_pmd(pmd, new_pmd);
        return 1;
}

int pmd_clear_huge(pmd_t *pmd)
{
        if (!pmd_leaf(pmdp_get(pmd)))
                return 0;
        pmd_clear(pmd);
        return 1;
}

int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
{
        pte_t *pte = (pte_t *)pmd_page_vaddr(pmdp_get(pmd));

        pmd_clear(pmd);

        flush_tlb_kernel_range(addr, addr + PMD_SIZE);
        pte_free_kernel(NULL, pte);
        return 1;
}

#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
                                        unsigned long address, pmd_t *pmdp)
{
        pmd_t pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);

        VM_BUG_ON(address & ~HPAGE_PMD_MASK);
        VM_BUG_ON(pmd_trans_huge(pmdp_get(pmdp)));
        /*
         * When leaf PTE entries (regular pages) are collapsed into a leaf
         * PMD entry (huge page), a valid non-leaf PTE is converted into a
         * valid leaf PTE at the level 1 page table.  Since the sfence.vma
         * forms that specify an address only apply to leaf PTEs, we need a
         * global flush here.  collapse_huge_page() assumes these flushes are
         * eager, so just do the fence here.
         */
        flush_tlb_mm(vma->vm_mm);
        return pmd;
}

pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
                      pud_t *pudp)
{
        VM_WARN_ON_ONCE(!pud_present(*pudp));
        pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));

        flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
        return old;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma)
{
        if (vma->vm_flags & VM_SHADOW_STACK)
                return pte_mkwrite_shstk(pte);

        return pte_mkwrite_novma(pte);
}

pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
{
        if (vma->vm_flags & VM_SHADOW_STACK)
                return pmd_mkwrite_shstk(pmd);

        return pmd_mkwrite_novma(pmd);
}