/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * arch/arm/include/asm/pgtable-3level.h
 *
 * Copyright (C) 2011 ARM Ltd.
 * Author: Catalin Marinas <catalin.marinas@arm.com>
 */
#ifndef _ASM_PGTABLE_3LEVEL_H
#define _ASM_PGTABLE_3LEVEL_H

/*
 * With LPAE, there are 3 levels of page tables. Each level has 512 entries of
 * 8 bytes each, occupying a 4K page. The first level table covers a range of
 * 512GB, each entry representing 1GB. Since we are limited to 4GB input
 * address range, only 4 entries in the PGD are used.
 *
 * There are enough spare bits in a page table entry for the kernel specific
 * state.
 */
#define PTRS_PER_PTE            512
#define PTRS_PER_PMD            512
#define PTRS_PER_PGD            4

#define PTE_HWTABLE_PTRS        (0)
#define PTE_HWTABLE_OFF         (0)
#define PTE_HWTABLE_SIZE        (PTRS_PER_PTE * sizeof(u64))

#define MAX_POSSIBLE_PHYSMEM_BITS 40

/*
 * PGDIR_SHIFT determines the size a top-level page table entry can map.
 */
#define PGDIR_SHIFT             30

/*
 * PMD_SHIFT determines the size a middle-level page table entry can map.
 */
#define PMD_SHIFT               21

#define PMD_SIZE                (1UL << PMD_SHIFT)
#define PMD_MASK                (~((1 << PMD_SHIFT) - 1))
#define PGDIR_SIZE              (1UL << PGDIR_SHIFT)
#define PGDIR_MASK              (~((1 << PGDIR_SHIFT) - 1))

/*
 * section address mask and size definitions.
 */
#define SECTION_SHIFT           21
#define SECTION_SIZE            (1UL << SECTION_SHIFT)
#define SECTION_MASK            (~((1 << SECTION_SHIFT) - 1))

#define USER_PTRS_PER_PGD       (PAGE_OFFSET / PGDIR_SIZE)

/*
 * Hugetlb definitions.
 */
#define HPAGE_SHIFT             PMD_SHIFT
#define HPAGE_SIZE              (_AC(1, UL) << HPAGE_SHIFT)
#define HPAGE_MASK              (~(HPAGE_SIZE - 1))
#define HUGETLB_PAGE_ORDER      (HPAGE_SHIFT - PAGE_SHIFT)

/*
 * "Linux" PTE definitions for LPAE.
 *
 * These bits overlap with the hardware bits but the naming is preserved for
 * consistency with the classic page table format.
 */
#define L_PTE_VALID             (_AT(pteval_t, 1) << 0)         /* Valid */
#define L_PTE_PRESENT           (_AT(pteval_t, 3) << 0)         /* Present */
#define L_PTE_USER              (_AT(pteval_t, 1) << 6)         /* AP[1] */
#define L_PTE_SHARED            (_AT(pteval_t, 3) << 8)         /* SH[1:0], inner shareable */
#define L_PTE_YOUNG             (_AT(pteval_t, 1) << 10)        /* AF */
#define L_PTE_XN                (_AT(pteval_t, 1) << 54)        /* XN */
#define L_PTE_DIRTY             (_AT(pteval_t, 1) << 55)
#define L_PTE_SPECIAL           (_AT(pteval_t, 1) << 56)
#define L_PTE_NONE              (_AT(pteval_t, 1) << 57)        /* PROT_NONE */
#define L_PTE_RDONLY            (_AT(pteval_t, 1) << 58)        /* READ ONLY */

/* We borrow bit 7 to store the exclusive marker in swap PTEs. */
#define L_PTE_SWP_EXCLUSIVE     (_AT(pteval_t, 1) << 7)

#define L_PMD_SECT_VALID        (_AT(pmdval_t, 1) << 0)
#define L_PMD_SECT_DIRTY        (_AT(pmdval_t, 1) << 55)
#define L_PMD_SECT_NONE         (_AT(pmdval_t, 1) << 57)
#define L_PMD_SECT_RDONLY       (_AT(pteval_t, 1) << 58)

/*
 * To be used in assembly code with the upper page attributes.
 */
#define L_PTE_XN_HIGH           (1 << (54 - 32))
#define L_PTE_DIRTY_HIGH        (1 << (55 - 32))

/*
 * AttrIndx[2:0] encoding (mapping attributes defined in the MAIR* registers).
 */
#define L_PTE_MT_UNCACHED       (_AT(pteval_t, 0) << 2) /* strongly ordered */
#define L_PTE_MT_BUFFERABLE     (_AT(pteval_t, 1) << 2) /* normal non-cacheable */
#define L_PTE_MT_WRITETHROUGH   (_AT(pteval_t, 2) << 2) /* normal inner write-through */
#define L_PTE_MT_WRITEBACK      (_AT(pteval_t, 3) << 2) /* normal inner write-back */
#define L_PTE_MT_WRITEALLOC     (_AT(pteval_t, 7) << 2) /* normal inner write-alloc */
#define L_PTE_MT_DEV_SHARED     (_AT(pteval_t, 4) << 2) /* device */
#define L_PTE_MT_DEV_NONSHARED  (_AT(pteval_t, 4) << 2) /* device */
#define L_PTE_MT_DEV_WC         (_AT(pteval_t, 1) << 2) /* normal non-cacheable */
#define L_PTE_MT_DEV_CACHED     (_AT(pteval_t, 3) << 2) /* normal inner write-back */
#define L_PTE_MT_MASK           (_AT(pteval_t, 7) << 2)

/*
 * Software PGD flags.
 */
#define L_PGD_SWAPPER           (_AT(pgdval_t, 1) << 55)        /* swapper_pg_dir entry */

#ifndef __ASSEMBLY__

#define pud_none(pud)           (!pud_val(pud))
#define pud_bad(pud)            (!(pud_val(pud) & PUD_TABLE_BIT))
#define pud_present(pud)        (pud_val(pud))
#define pmd_table(pmd)          ((pmd_val(pmd) & PMD_TYPE_MASK) == \
                                                 PMD_TYPE_TABLE)
#define pmd_sect(pmd)           ((pmd_val(pmd) & PMD_TYPE_MASK) == \
                                                 PMD_TYPE_SECT)
#define pmd_leaf(pmd)           pmd_sect(pmd)

#define pud_clear(pudp)                 \
        do {                            \
                *pudp = __pud(0);       \
                clean_pmd_entry(pudp);  \
        } while (0)

#define set_pud(pudp, pud)              \
        do {                            \
                *pudp = pud;            \
                flush_pmd_entry(pudp);  \
        } while (0)

static inline pmd_t *pud_pgtable(pud_t pud)
{
        return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
}

#define pmd_bad(pmd)            (!(pmd_val(pmd) & PMD_TABLE_BIT))

#define copy_pmd(pmdpd,pmdps)           \
        do {                            \
                *pmdpd = *pmdps;        \
                flush_pmd_entry(pmdpd); \
        } while (0)

#define pmd_clear(pmdp)                 \
        do {                            \
                *pmdp = __pmd(0);       \
                clean_pmd_entry(pmdp);  \
        } while (0)

/*
 * For 3 levels of paging the PTE_EXT_NG bit will be set for user address ptes
 * that are written to a page table but not for ptes created with mk_pte.
 *
 * In hugetlb_no_page, a new huge pte (new_pte) is generated and passed to
 * hugetlb_cow, where it is compared with an entry in a page table.
 * This comparison test fails erroneously leading ultimately to a memory leak.
 *
 * To correct this behaviour, we mask off PTE_EXT_NG for any pte that is
 * present before running the comparison.
 */
#define __HAVE_ARCH_PTE_SAME
#define pte_same(pte_a,pte_b)   ((pte_present(pte_a) ? pte_val(pte_a) & ~PTE_EXT_NG     \
                                        : pte_val(pte_a))                               \
                                == (pte_present(pte_b) ? pte_val(pte_b) & ~PTE_EXT_NG   \
                                        : pte_val(pte_b)))

#define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,__pte(pte_val(pte)|(ext)))

#define pte_huge(pte)           (pte_val(pte) && !(pte_val(pte) & PTE_TABLE_BIT))
#define pte_mkhuge(pte)         (__pte(pte_val(pte) & ~PTE_TABLE_BIT))

#define pmd_isset(pmd, val)     ((u32)(val) == (val) ? pmd_val(pmd) & (val) \
                                                : !!(pmd_val(pmd) & (val)))
#define pmd_isclear(pmd, val)   (!(pmd_val(pmd) & (val)))

#define pmd_present(pmd)        (pmd_isset((pmd), L_PMD_SECT_VALID))
#define pmd_young(pmd)          (pmd_isset((pmd), PMD_SECT_AF))
#define pte_special(pte)        (pte_isset((pte), L_PTE_SPECIAL))
static inline pte_t pte_mkspecial(pte_t pte)
{
        pte_val(pte) |= L_PTE_SPECIAL;
        return pte;
}

#define pmd_write(pmd)          (pmd_isclear((pmd), L_PMD_SECT_RDONLY))
#define pmd_dirty(pmd)          (pmd_isset((pmd), L_PMD_SECT_DIRTY))

#define pmd_hugewillfault(pmd)  (!pmd_young(pmd) || !pmd_write(pmd))

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define pmd_trans_huge(pmd)     (pmd_val(pmd) && !pmd_table(pmd))
#endif

#define PMD_BIT_FUNC(fn,op) \
static inline pmd_t pmd_##fn(pmd_t pmd) { pmd_val(pmd) op; return pmd; }

PMD_BIT_FUNC(wrprotect, |= L_PMD_SECT_RDONLY);
PMD_BIT_FUNC(mkold,     &= ~PMD_SECT_AF);
PMD_BIT_FUNC(mkwrite_novma,   &= ~L_PMD_SECT_RDONLY);
PMD_BIT_FUNC(mkdirty,   |= L_PMD_SECT_DIRTY);
PMD_BIT_FUNC(mkclean,   &= ~L_PMD_SECT_DIRTY);
PMD_BIT_FUNC(mkyoung,   |= PMD_SECT_AF);

#define pmd_mkhuge(pmd)         (__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))

#define pmd_pfn(pmd)            (((pmd_val(pmd) & PMD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
#define pfn_pmd(pfn,prot)       (__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))

/* No hardware dirty/accessed bits -- generic_pmdp_establish() fits */
#define pmdp_establish generic_pmdp_establish

/* represent a notpresent pmd by faulting entry, this is used by pmdp_invalidate */
static inline pmd_t pmd_mkinvalid(pmd_t pmd)
{
        return __pmd(pmd_val(pmd) & ~L_PMD_SECT_VALID);
}

static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
{
        const pmdval_t mask = PMD_SECT_USER | PMD_SECT_XN | L_PMD_SECT_RDONLY |
                                L_PMD_SECT_VALID | L_PMD_SECT_NONE;
        pmd_val(pmd) = (pmd_val(pmd) & ~mask) | (pgprot_val(newprot) & mask);
        return pmd;
}

static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
                              pmd_t *pmdp, pmd_t pmd)
{
        BUG_ON(addr >= TASK_SIZE);

        /* create a faulting entry if PROT_NONE protected */
        if (pmd_val(pmd) & L_PMD_SECT_NONE)
                pmd_val(pmd) &= ~L_PMD_SECT_VALID;

        if (pmd_write(pmd) && pmd_dirty(pmd))
                pmd_val(pmd) &= ~PMD_SECT_AP2;
        else
                pmd_val(pmd) |= PMD_SECT_AP2;

        *pmdp = __pmd(pmd_val(pmd) | PMD_SECT_nG);
        flush_pmd_entry(pmdp);
}

#endif /* __ASSEMBLY__ */

#endif /* _ASM_PGTABLE_3LEVEL_H */