arch/sh/include/asm/pgtable.h

/* SPDX-License-Identifier: GPL-2.0
 *
 * This file contains the functions and defines necessary to modify and
 * use the SuperH page table tree.
 *
 * Copyright (C) 1999 Niibe Yutaka
 * Copyright (C) 2002 - 2007 Paul Mundt
 */
#ifndef __ASM_SH_PGTABLE_H
#define __ASM_SH_PGTABLE_H

#ifdef CONFIG_X2TLB
#include <asm/pgtable-3level.h>
#else
#include <asm/pgtable-2level.h>
#endif
#include <asm/page.h>
#include <asm/mmu.h>

#ifndef __ASSEMBLY__
#include <asm/addrspace.h>
#include <asm/fixmap.h>

/*
 * ZERO_PAGE is a global shared page that is always zero: used
 * for zero-mapped memory areas etc..
 */
extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))

#endif /* !__ASSEMBLY__ */

/*
 * Effective and physical address definitions, to aid with sign
 * extension.
 */
#define NEFF		32
#define	NEFF_SIGN	(1LL << (NEFF - 1))
#define	NEFF_MASK	(-1LL << NEFF)

static inline unsigned long long neff_sign_extend(unsigned long val)
{
	unsigned long long extended = val;
	return (extended & NEFF_SIGN) ? (extended | NEFF_MASK) : extended;
}

#ifdef CONFIG_29BIT
#define NPHYS		29
#else
#define NPHYS		32
#endif

#define	NPHYS_SIGN	(1LL << (NPHYS - 1))
#define	NPHYS_MASK	(-1LL << NPHYS)

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

/* Entries per level */
#define PTRS_PER_PTE	(PAGE_SIZE / (1 << PTE_MAGNITUDE))

#define PHYS_ADDR_MASK29		0x1fffffff
#define PHYS_ADDR_MASK32		0xffffffff

static inline unsigned long phys_addr_mask(void)
{
	/* Is the MMU in 29bit mode? */
	if (__in_29bit_mode())
		return PHYS_ADDR_MASK29;

	return PHYS_ADDR_MASK32;
}

#define PTE_PHYS_MASK		(phys_addr_mask() & PAGE_MASK)
#define PTE_FLAGS_MASK		(~(PTE_PHYS_MASK) << PAGE_SHIFT)

#define VMALLOC_START	(P3SEG)
#define VMALLOC_END	(FIXADDR_START-2*PAGE_SIZE)

#include <asm/pgtable_32.h>

/*
 * SH-X and lower (legacy) SuperH parts (SH-3, SH-4, some SH-4A) can't do page
 * protection for execute, and considers it the same as a read. Also, write
 * permission implies read permission. This is the closest we can get..
 *
 * SH-X2 (SH7785) and later parts take this to the opposite end of the extreme,
 * not only supporting separate execute, read, and write bits, but having
 * completely separate permission bits for user and kernel space.
 */
	 /*xwr*/

typedef pte_t *pte_addr_t;

#define pte_pfn(x)		((unsigned long)(((x).pte_low >> PAGE_SHIFT)))

struct vm_area_struct;
struct mm_struct;

extern void __update_cache(struct vm_area_struct *vma,
			   unsigned long address, pte_t pte);
extern void __update_tlb(struct vm_area_struct *vma,
			 unsigned long address, pte_t pte);

static inline void
update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep)
{
	pte_t pte = *ptep;
	__update_cache(vma, address, pte);
	__update_tlb(vma, address, pte);
}

extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern void paging_init(void);
extern void page_table_range_init(unsigned long start, unsigned long end,
				  pgd_t *pgd);

static inline bool __pte_access_permitted(pte_t pte, u64 prot)
{
	return (pte_val(pte) & (prot | _PAGE_SPECIAL)) == prot;
}

#ifdef CONFIG_X2TLB
static inline bool pte_access_permitted(pte_t pte, bool write)
{
	u64 prot = _PAGE_PRESENT;

	prot |= _PAGE_EXT(_PAGE_EXT_KERN_READ | _PAGE_EXT_USER_READ);
	if (write)
		prot |= _PAGE_EXT(_PAGE_EXT_KERN_WRITE | _PAGE_EXT_USER_WRITE);
	return __pte_access_permitted(pte, prot);
}
#else
static inline bool pte_access_permitted(pte_t pte, bool write)
{
	u64 prot = _PAGE_PRESENT | _PAGE_USER;

	if (write)
		prot |= _PAGE_RW;
	return __pte_access_permitted(pte, prot);
}
#endif

#define pte_access_permitted pte_access_permitted

/* arch/sh/mm/mmap.c */
#define HAVE_ARCH_UNMAPPED_AREA
#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN

#endif /* __ASM_SH_PGTABLE_H */