pgtable.h

/*
 *  S390 version
 *    Copyright IBM Corp. 1999, 2000
 *    Author(s): Hartmut Penner (hp@de.ibm.com)
 *               Ulrich Weigand (weigand@de.ibm.com)
 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
 *
 *  Derived from "include/asm-i386/pgtable.h"
 */

#ifndef _ASM_S390_PGTABLE_H
#define _ASM_S390_PGTABLE_H

/*
 * The Linux memory management assumes a three-level page table setup.
 * For s390 64 bit we use up to four of the five levels the hardware
 * provides (region first tables are not used).
 *
 * The "pgd_xxx()" functions are trivial for a folded two-level
 * setup: the pgd is never bad, and a pmd always exists (as it's folded
 * into the pgd entry)
 *
 * This file contains the functions and defines necessary to modify and use
 * the S390 page table tree.
 */
#ifndef __ASSEMBLY__
#include <linux/sched.h>
#include <linux/mm_types.h>
#include <linux/page-flags.h>
#include <linux/radix-tree.h>
#include <linux/atomic.h>
#include <asm/bug.h>
#include <asm/page.h>

extern pgd_t swapper_pg_dir[];
extern void paging_init(void);
extern void vmem_map_init(void);
pmd_t *vmem_pmd_alloc(void);
pte_t *vmem_pte_alloc(void);

enum {
	PG_DIRECT_MAP_4K = 0,
	PG_DIRECT_MAP_1M,
	PG_DIRECT_MAP_2G,
	PG_DIRECT_MAP_MAX
};

extern atomic_long_t direct_pages_count[PG_DIRECT_MAP_MAX];

static inline void update_page_count(int level, long count)
{
	if (IS_ENABLED(CONFIG_PROC_FS))
		atomic_long_add(count, &direct_pages_count[level]);
}

struct seq_file;
void arch_report_meminfo(struct seq_file *m);

/*
 * The S390 doesn't have any external MMU info: the kernel page
 * tables contain all the necessary information.
 */
#define update_mmu_cache(vma, address, ptep)     do { } while (0)
#define update_mmu_cache_pmd(vma, address, ptep) do { } while (0)

/*
 * ZERO_PAGE is a global shared page that is always zero; used
 * for zero-mapped memory areas etc..
 */

extern unsigned long empty_zero_page;
extern unsigned long zero_page_mask;

#define ZERO_PAGE(vaddr) \
	(virt_to_page((void *)(empty_zero_page + \
	 (((unsigned long)(vaddr)) &zero_page_mask))))
#define __HAVE_COLOR_ZERO_PAGE

/* TODO: s390 cannot support io_remap_pfn_range... */
#endif /* !__ASSEMBLY__ */

/*
 * PMD_SHIFT determines the size of the area a second-level page
 * table can map
 * PGDIR_SHIFT determines what a third-level page table entry can map
 */
#define PMD_SHIFT	20
#define PUD_SHIFT	31
#define P4D_SHIFT	42
#define PGDIR_SHIFT	53

#define PMD_SIZE        (1UL << PMD_SHIFT)
#define PMD_MASK        (~(PMD_SIZE-1))
#define PUD_SIZE	(1UL << PUD_SHIFT)
#define PUD_MASK	(~(PUD_SIZE-1))
#define P4D_SIZE	(1UL << P4D_SHIFT)
#define P4D_MASK	(~(P4D_SIZE-1))
#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
#define PGDIR_MASK	(~(PGDIR_SIZE-1))

/*
 * entries per page directory level: the S390 is two-level, so
 * we don't really have any PMD directory physically.
 * for S390 segment-table entries are combined to one PGD
 * that leads to 1024 pte per pgd
 */
#define PTRS_PER_PTE	256
#define PTRS_PER_PMD	2048
#define PTRS_PER_PUD	2048
#define PTRS_PER_P4D	2048
#define PTRS_PER_PGD	2048

#define FIRST_USER_ADDRESS  0UL

#define pte_ERROR(e) \
	printk("%s:%d: bad pte %p.\n", __FILE__, __LINE__, (void *) pte_val(e))
#define pmd_ERROR(e) \
	printk("%s:%d: bad pmd %p.\n", __FILE__, __LINE__, (void *) pmd_val(e))
#define pud_ERROR(e) \
	printk("%s:%d: bad pud %p.\n", __FILE__, __LINE__, (void *) pud_val(e))
#define p4d_ERROR(e) \
	printk("%s:%d: bad p4d %p.\n", __FILE__, __LINE__, (void *) p4d_val(e))
#define pgd_ERROR(e) \
	printk("%s:%d: bad pgd %p.\n", __FILE__, __LINE__, (void *) pgd_val(e))

#ifndef __ASSEMBLY__
/*
 * The vmalloc and module area will always be on the topmost area of the
 * kernel mapping. We reserve 128GB (64bit) for vmalloc and modules.
 * On 64 bit kernels we have a 2GB area at the top of the vmalloc area where
 * modules will reside. That makes sure that inter module branches always
 * happen without trampolines and in addition the placement within a 2GB frame
 * is branch prediction unit friendly.
 */
extern unsigned long VMALLOC_START;
extern unsigned long VMALLOC_END;
extern struct page *vmemmap;

#define VMEM_MAX_PHYS ((unsigned long) vmemmap)

extern unsigned long MODULES_VADDR;
extern unsigned long MODULES_END;
#define MODULES_VADDR	MODULES_VADDR
#define MODULES_END	MODULES_END
#define MODULES_LEN	(1UL << 31)

static inline int is_module_addr(void *addr)
{
	BUILD_BUG_ON(MODULES_LEN > (1UL << 31));
	if (addr < (void *)MODULES_VADDR)
		return 0;
	if (addr > (void *)MODULES_END)
		return 0;
	return 1;
}

/*
 * A 64 bit pagetable entry of S390 has following format:
 * |			 PFRA			      |0IPC|  OS  |
 * 0000000000111111111122222222223333333333444444444455555555556666
 * 0123456789012345678901234567890123456789012345678901234567890123
 *
 * I Page-Invalid Bit:    Page is not available for address-translation
 * P Page-Protection Bit: Store access not possible for page
 * C Change-bit override: HW is not required to set change bit
 *
 * A 64 bit segmenttable entry of S390 has following format:
 * |        P-table origin                              |      TT
 * 0000000000111111111122222222223333333333444444444455555555556666
 * 0123456789012345678901234567890123456789012345678901234567890123
 *
 * I Segment-Invalid Bit:    Segment is not available for address-translation
 * C Common-Segment Bit:     Segment is not private (PoP 3-30)
 * P Page-Protection Bit: Store access not possible for page
 * TT Type 00
 *
 * A 64 bit region table entry of S390 has following format:
 * |        S-table origin                             |   TF  TTTL
 * 0000000000111111111122222222223333333333444444444455555555556666
 * 0123456789012345678901234567890123456789012345678901234567890123
 *
 * I Segment-Invalid Bit:    Segment is not available for address-translation
 * TT Type 01
 * TF
 * TL Table length
 *
 * The 64 bit regiontable origin of S390 has following format:
 * |      region table origon                          |       DTTL
 * 0000000000111111111122222222223333333333444444444455555555556666
 * 0123456789012345678901234567890123456789012345678901234567890123
 *
 * X Space-Switch event:
 * G Segment-Invalid Bit:  
 * P Private-Space Bit:    
 * S Storage-Alteration:
 * R Real space
 * TL Table-Length:
 *
 * A storage key has the following format:
 * | ACC |F|R|C|0|
 *  0   3 4 5 6 7
 * ACC: access key
 * F  : fetch protection bit
 * R  : referenced bit
 * C  : changed bit
 */

/* Hardware bits in the page table entry */
#define _PAGE_NOEXEC	0x100		/* HW no-execute bit  */
#define _PAGE_PROTECT	0x200		/* HW read-only bit  */
#define _PAGE_INVALID	0x400		/* HW invalid bit    */
#define _PAGE_LARGE	0x800		/* Bit to mark a large pte */

/* Software bits in the page table entry */
#define _PAGE_PRESENT	0x001		/* SW pte present bit */
#define _PAGE_YOUNG	0x004		/* SW pte young bit */
#define _PAGE_DIRTY	0x008		/* SW pte dirty bit */
#define _PAGE_READ	0x010		/* SW pte read bit */
#define _PAGE_WRITE	0x020		/* SW pte write bit */
#define _PAGE_SPECIAL	0x040		/* SW associated with special page */
#define _PAGE_UNUSED	0x080		/* SW bit for pgste usage state */
#define __HAVE_ARCH_PTE_SPECIAL

#ifdef CONFIG_MEM_SOFT_DIRTY
#define _PAGE_SOFT_DIRTY 0x002		/* SW pte soft dirty bit */
#else
#define _PAGE_SOFT_DIRTY 0x000
#endif

/* Set of bits not changed in pte_modify */
#define _PAGE_CHG_MASK		(PAGE_MASK | _PAGE_SPECIAL | _PAGE_DIRTY | \
				 _PAGE_YOUNG | _PAGE_SOFT_DIRTY)

/*
 * handle_pte_fault uses pte_present and pte_none to find out the pte type
 * WITHOUT holding the page table lock. The _PAGE_PRESENT bit is used to
 * distinguish present from not-present ptes. It is changed only with the page
 * table lock held.
 *
 * The following table gives the different possible bit combinations for
 * the pte hardware and software bits in the last 12 bits of a pte
 * (. unassigned bit, x don't care, t swap type):
 *
 *				842100000000
 *				000084210000
 *				000000008421
 *				.IR.uswrdy.p
 * empty			.10.00000000
 * swap				.11..ttttt.0
 * prot-none, clean, old	.11.xx0000.1
 * prot-none, clean, young	.11.xx0001.1
 * prot-none, dirty, old	.11.xx0010.1
 * prot-none, dirty, young	.11.xx0011.1
 * read-only, clean, old	.11.xx0100.1
 * read-only, clean, young	.01.xx0101.1
 * read-only, dirty, old	.11.xx0110.1
 * read-only, dirty, young	.01.xx0111.1
 * read-write, clean, old	.11.xx1100.1
 * read-write, clean, young	.01.xx1101.1
 * read-write, dirty, old	.10.xx1110.1
 * read-write, dirty, young	.00.xx1111.1
 * HW-bits: R read-only, I invalid
 * SW-bits: p present, y young, d dirty, r read, w write, s special,
 *	    u unused, l large
 *
 * pte_none    is true for the bit pattern .10.00000000, pte == 0x400
 * pte_swap    is true for the bit pattern .11..ooooo.0, (pte & 0x201) == 0x200
 * pte_present is true for the bit pattern .xx.xxxxxx.1, (pte & 0x001) == 0x001
 */

/* Bits in the segment/region table address-space-control-element */
#define _ASCE_ORIGIN		~0xfffUL/* segment table origin		    */
#define _ASCE_PRIVATE_SPACE	0x100	/* private space control	    */
#define _ASCE_ALT_EVENT		0x80	/* storage alteration event control */
#define _ASCE_SPACE_SWITCH	0x40	/* space switch event		    */
#define _ASCE_REAL_SPACE	0x20	/* real space control		    */
#define _ASCE_TYPE_MASK		0x0c	/* asce table type mask		    */
#define _ASCE_TYPE_REGION1	0x0c	/* region first table type	    */
#define _ASCE_TYPE_REGION2	0x08	/* region second table type	    */
#define _ASCE_TYPE_REGION3	0x04	/* region third table type	    */
#define _ASCE_TYPE_SEGMENT	0x00	/* segment table type		    */
#define _ASCE_TABLE_LENGTH	0x03	/* region table length		    */

/* Bits in the region table entry */
#define _REGION_ENTRY_ORIGIN	~0xfffUL/* region/segment table origin	    */
#define _REGION_ENTRY_PROTECT	0x200	/* region protection bit	    */
#define _REGION_ENTRY_NOEXEC	0x100	/* region no-execute bit	    */
#define _REGION_ENTRY_OFFSET	0xc0	/* region table offset		    */
#define _REGION_ENTRY_INVALID	0x20	/* invalid region table entry	    */
#define _REGION_ENTRY_TYPE_MASK	0x0c	/* region/segment table type mask   */
#define _REGION_ENTRY_TYPE_R1	0x0c	/* region first table type	    */
#define _REGION_ENTRY_TYPE_R2	0x08	/* region second table type	    */
#define _REGION_ENTRY_TYPE_R3	0x04	/* region third table type	    */
#define _REGION_ENTRY_LENGTH	0x03	/* region third length		    */

#define _REGION1_ENTRY		(_REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_LENGTH)
#define _REGION1_ENTRY_EMPTY	(_REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID)
#define _REGION2_ENTRY		(_REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_LENGTH)
#define _REGION2_ENTRY_EMPTY	(_REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID)
#define _REGION3_ENTRY		(_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_LENGTH)
#define _REGION3_ENTRY_EMPTY	(_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID)

#define _REGION3_ENTRY_ORIGIN_LARGE ~0x7fffffffUL /* large page address	     */
#define _REGION3_ENTRY_DIRTY	0x2000	/* SW region dirty bit */
#define _REGION3_ENTRY_YOUNG	0x1000	/* SW region young bit */
#define _REGION3_ENTRY_LARGE	0x0400	/* RTTE-format control, large page  */
#define _REGION3_ENTRY_READ	0x0002	/* SW region read bit */
#define _REGION3_ENTRY_WRITE	0x0001	/* SW region write bit */

#ifdef CONFIG_MEM_SOFT_DIRTY
#define _REGION3_ENTRY_SOFT_DIRTY 0x4000 /* SW region soft dirty bit */
#else
#define _REGION3_ENTRY_SOFT_DIRTY 0x0000 /* SW region soft dirty bit */
#endif

#define _REGION_ENTRY_BITS	 0xfffffffffffff22fUL
#define _REGION_ENTRY_BITS_LARGE 0xffffffff8000fe2fUL

/* Bits in the segment table entry */
#define _SEGMENT_ENTRY_BITS	0xfffffffffffffe33UL
#define _SEGMENT_ENTRY_BITS_LARGE 0xfffffffffff0ff33UL
#define _SEGMENT_ENTRY_ORIGIN_LARGE ~0xfffffUL /* large page address	    */
#define _SEGMENT_ENTRY_ORIGIN	~0x7ffUL/* segment table origin		    */
#define _SEGMENT_ENTRY_PROTECT	0x200	/* page protection bit		    */
#define _SEGMENT_ENTRY_NOEXEC	0x100	/* region no-execute bit	    */
#define _SEGMENT_ENTRY_INVALID	0x20	/* invalid segment table entry	    */

#define _SEGMENT_ENTRY		(0)
#define _SEGMENT_ENTRY_EMPTY	(_SEGMENT_ENTRY_INVALID)

#define _SEGMENT_ENTRY_DIRTY	0x2000	/* SW segment dirty bit */
#define _SEGMENT_ENTRY_YOUNG	0x1000	/* SW segment young bit */
#define _SEGMENT_ENTRY_LARGE	0x0400	/* STE-format control, large page */
#define _SEGMENT_ENTRY_WRITE	0x0002	/* SW segment write bit */
#define _SEGMENT_ENTRY_READ	0x0001	/* SW segment read bit */

#ifdef CONFIG_MEM_SOFT_DIRTY
#define _SEGMENT_ENTRY_SOFT_DIRTY 0x4000 /* SW segment soft dirty bit */
#else
#define _SEGMENT_ENTRY_SOFT_DIRTY 0x0000 /* SW segment soft dirty bit */
#endif

/*
 * Segment table and region3 table entry encoding
 * (R = read-only, I = invalid, y = young bit):
 *				dy..R...I...wr
 * prot-none, clean, old	00..1...1...00
 * prot-none, clean, young	01..1...1...00
 * prot-none, dirty, old	10..1...1...00
 * prot-none, dirty, young	11..1...1...00
 * read-only, clean, old	00..1...1...01
 * read-only, clean, young	01..1...0...01
 * read-only, dirty, old	10..1...1...01
 * read-only, dirty, young	11..1...0...01
 * read-write, clean, old	00..1...1...11
 * read-write, clean, young	01..1...0...11
 * read-write, dirty, old	10..0...1...11
 * read-write, dirty, young	11..0...0...11
 * The segment table origin is used to distinguish empty (origin==0) from
 * read-write, old segment table entries (origin!=0)
 * HW-bits: R read-only, I invalid
 * SW-bits: y young, d dirty, r read, w write
 */

/* Page status table bits for virtualization */
#define PGSTE_ACC_BITS	0xf000000000000000UL
#define PGSTE_FP_BIT	0x0800000000000000UL
#define PGSTE_PCL_BIT	0x0080000000000000UL
#define PGSTE_HR_BIT	0x0040000000000000UL
#define PGSTE_HC_BIT	0x0020000000000000UL
#define PGSTE_GR_BIT	0x0004000000000000UL
#define PGSTE_GC_BIT	0x0002000000000000UL
#define PGSTE_UC_BIT	0x0000800000000000UL	/* user dirty (migration) */
#define PGSTE_IN_BIT	0x0000400000000000UL	/* IPTE notify bit */
#define PGSTE_VSIE_BIT	0x0000200000000000UL	/* ref'd in a shadow table */

/* Guest Page State used for virtualization */
#define _PGSTE_GPS_ZERO			0x0000000080000000UL
#define _PGSTE_GPS_USAGE_MASK		0x0000000003000000UL
#define _PGSTE_GPS_USAGE_STABLE		0x0000000000000000UL
#define _PGSTE_GPS_USAGE_UNUSED		0x0000000001000000UL
#define _PGSTE_GPS_USAGE_POT_VOLATILE	0x0000000002000000UL
#define _PGSTE_GPS_USAGE_VOLATILE	_PGSTE_GPS_USAGE_MASK

/*
 * A user page table pointer has the space-switch-event bit, the
 * private-space-control bit and the storage-alteration-event-control
 * bit set. A kernel page table pointer doesn't need them.
 */
#define _ASCE_USER_BITS		(_ASCE_SPACE_SWITCH | _ASCE_PRIVATE_SPACE | \
				 _ASCE_ALT_EVENT)

/*
 * Page protection definitions.
 */
#define PAGE_NONE	__pgprot(_PAGE_PRESENT | _PAGE_INVALID | _PAGE_PROTECT)
#define PAGE_RO		__pgprot(_PAGE_PRESENT | _PAGE_READ | \
				 _PAGE_NOEXEC  | _PAGE_INVALID | _PAGE_PROTECT)
#define PAGE_RX		__pgprot(_PAGE_PRESENT | _PAGE_READ | \
				 _PAGE_INVALID | _PAGE_PROTECT)
#define PAGE_RW		__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \
				 _PAGE_NOEXEC  | _PAGE_INVALID | _PAGE_PROTECT)
#define PAGE_RWX	__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \
				 _PAGE_INVALID | _PAGE_PROTECT)

#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \
				 _PAGE_YOUNG | _PAGE_DIRTY | _PAGE_NOEXEC)
#define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \
				 _PAGE_YOUNG | _PAGE_DIRTY | _PAGE_NOEXEC)
#define PAGE_KERNEL_RO	__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_YOUNG | \
				 _PAGE_PROTECT | _PAGE_NOEXEC)
#define PAGE_KERNEL_EXEC __pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \
				  _PAGE_YOUNG |	_PAGE_DIRTY)

/*
 * On s390 the page table entry has an invalid bit and a read-only bit.
 * Read permission implies execute permission and write permission
 * implies read permission.
 */
         /*xwr*/
#define __P000	PAGE_NONE
#define __P001	PAGE_RO
#define __P010	PAGE_RO
#define __P011	PAGE_RO
#define __P100	PAGE_RX
#define __P101	PAGE_RX
#define __P110	PAGE_RX
#define __P111	PAGE_RX

#define __S000	PAGE_NONE
#define __S001	PAGE_RO
#define __S010	PAGE_RW
#define __S011	PAGE_RW
#define __S100	PAGE_RX
#define __S101	PAGE_RX
#define __S110	PAGE_RWX
#define __S111	PAGE_RWX

/*
 * Segment entry (large page) protection definitions.
 */
#define SEGMENT_NONE	__pgprot(_SEGMENT_ENTRY_INVALID | \
				 _SEGMENT_ENTRY_PROTECT)
#define SEGMENT_RO	__pgprot(_SEGMENT_ENTRY_PROTECT | \
				 _SEGMENT_ENTRY_READ | \
				 _SEGMENT_ENTRY_NOEXEC)
#define SEGMENT_RX	__pgprot(_SEGMENT_ENTRY_PROTECT | \
				 _SEGMENT_ENTRY_READ)
#define SEGMENT_RW	__pgprot(_SEGMENT_ENTRY_READ | \
				 _SEGMENT_ENTRY_WRITE | \
				 _SEGMENT_ENTRY_NOEXEC)
#define SEGMENT_RWX	__pgprot(_SEGMENT_ENTRY_READ | \
				 _SEGMENT_ENTRY_WRITE)
#define SEGMENT_KERNEL	__pgprot(_SEGMENT_ENTRY |	\
				 _SEGMENT_ENTRY_LARGE |	\
				 _SEGMENT_ENTRY_READ |	\
				 _SEGMENT_ENTRY_WRITE | \
				 _SEGMENT_ENTRY_YOUNG | \
				 _SEGMENT_ENTRY_DIRTY | \
				 _SEGMENT_ENTRY_NOEXEC)
#define SEGMENT_KERNEL_RO __pgprot(_SEGMENT_ENTRY |	\
				 _SEGMENT_ENTRY_LARGE |	\
				 _SEGMENT_ENTRY_READ |	\
				 _SEGMENT_ENTRY_YOUNG |	\
				 _SEGMENT_ENTRY_PROTECT | \
				 _SEGMENT_ENTRY_NOEXEC)

/*
 * Region3 entry (large page) protection definitions.
 */

#define REGION3_KERNEL	__pgprot(_REGION_ENTRY_TYPE_R3 | \
				 _REGION3_ENTRY_LARGE |	 \
				 _REGION3_ENTRY_READ |	 \
				 _REGION3_ENTRY_WRITE |	 \
				 _REGION3_ENTRY_YOUNG |	 \
				 _REGION3_ENTRY_DIRTY | \
				 _REGION_ENTRY_NOEXEC)
#define REGION3_KERNEL_RO __pgprot(_REGION_ENTRY_TYPE_R3 | \
				   _REGION3_ENTRY_LARGE |  \
				   _REGION3_ENTRY_READ |   \
				   _REGION3_ENTRY_YOUNG |  \
				   _REGION_ENTRY_PROTECT | \
				   _REGION_ENTRY_NOEXEC)

static inline int mm_has_pgste(struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
	if (unlikely(mm->context.has_pgste))
		return 1;
#endif
	return 0;
}

static inline int mm_alloc_pgste(struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
	if (unlikely(mm->context.alloc_pgste))
		return 1;
#endif
	return 0;
}

/*
 * In the case that a guest uses storage keys
 * faults should no longer be backed by zero pages
 */
#define mm_forbids_zeropage mm_use_skey
static inline int mm_use_skey(struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
	if (mm->context.use_skey)
		return 1;
#endif
	return 0;
}

static inline void csp(unsigned int *ptr, unsigned int old, unsigned int new)
{
	register unsigned long reg2 asm("2") = old;
	register unsigned long reg3 asm("3") = new;
	unsigned long address = (unsigned long)ptr | 1;

	asm volatile(
		"	csp	%0,%3"
		: "+d" (reg2), "+m" (*ptr)
		: "d" (reg3), "d" (address)
		: "cc");
}

static inline void cspg(unsigned long *ptr, unsigned long old, unsigned long new)
{
	register unsigned long reg2 asm("2") = old;
	register unsigned long reg3 asm("3") = new;
	unsigned long address = (unsigned long)ptr | 1;

	asm volatile(
		"	.insn	rre,0xb98a0000,%0,%3"
		: "+d" (reg2), "+m" (*ptr)
		: "d" (reg3), "d" (address)
		: "cc");
}

#define CRDTE_DTT_PAGE		0x00UL
#define CRDTE_DTT_SEGMENT	0x10UL
#define CRDTE_DTT_REGION3	0x14UL
#define CRDTE_DTT_REGION2	0x18UL
#define CRDTE_DTT_REGION1	0x1cUL

static inline void crdte(unsigned long old, unsigned long new,
			 unsigned long table, unsigned long dtt,
			 unsigned long address, unsigned long asce)
{
	register unsigned long reg2 asm("2") = old;
	register unsigned long reg3 asm("3") = new;
	register unsigned long reg4 asm("4") = table | dtt;
	register unsigned long reg5 asm("5") = address;

	asm volatile(".insn rrf,0xb98f0000,%0,%2,%4,0"
		     : "+d" (reg2)
		     : "d" (reg3), "d" (reg4), "d" (reg5), "a" (asce)
		     : "memory", "cc");
}

/*
 * pgd/p4d/pud/pmd/pte query functions
 */
static inline int pgd_folded(pgd_t pgd)
{
	return (pgd_val(pgd) & _REGION_ENTRY_TYPE_MASK) < _REGION_ENTRY_TYPE_R1;
}

static inline int pgd_present(pgd_t pgd)
{
	if (pgd_folded(pgd))
		return 1;
	return (pgd_val(pgd) & _REGION_ENTRY_ORIGIN) != 0UL;
}

static inline int pgd_none(pgd_t pgd)
{
	if (pgd_folded(pgd))
		return 0;
	return (pgd_val(pgd) & _REGION_ENTRY_INVALID) != 0UL;
}

static inline int pgd_bad(pgd_t pgd)
{
	/*
	 * With dynamic page table levels the pgd can be a region table
	 * entry or a segment table entry. Check for the bit that are
	 * invalid for either table entry.
	 */
	unsigned long mask =
		~_SEGMENT_ENTRY_ORIGIN & ~_REGION_ENTRY_INVALID &
		~_REGION_ENTRY_TYPE_MASK & ~_REGION_ENTRY_LENGTH;
	return (pgd_val(pgd) & mask) != 0;
}

static inline int p4d_folded(p4d_t p4d)
{
	return (p4d_val(p4d) & _REGION_ENTRY_TYPE_MASK) < _REGION_ENTRY_TYPE_R2;
}

static inline int p4d_present(p4d_t p4d)
{
	if (p4d_folded(p4d))
		return 1;
	return (p4d_val(p4d) & _REGION_ENTRY_ORIGIN) != 0UL;
}

static inline int p4d_none(p4d_t p4d)
{
	if (p4d_folded(p4d))
		return 0;
	return p4d_val(p4d) == _REGION2_ENTRY_EMPTY;
}

static inline unsigned long p4d_pfn(p4d_t p4d)
{
	unsigned long origin_mask;

	origin_mask = _REGION_ENTRY_ORIGIN;
	return (p4d_val(p4d) & origin_mask) >> PAGE_SHIFT;
}

static inline int pud_folded(pud_t pud)
{
	return (pud_val(pud) & _REGION_ENTRY_TYPE_MASK) < _REGION_ENTRY_TYPE_R3;
}

static inline int pud_present(pud_t pud)
{
	if (pud_folded(pud))
		return 1;
	return (pud_val(pud) & _REGION_ENTRY_ORIGIN) != 0UL;
}

static inline int pud_none(pud_t pud)
{
	if (pud_folded(pud))
		return 0;
	return pud_val(pud) == _REGION3_ENTRY_EMPTY;
}

static inline int pud_large(pud_t pud)
{
	if ((pud_val(pud) & _REGION_ENTRY_TYPE_MASK) != _REGION_ENTRY_TYPE_R3)
		return 0;
	return !!(pud_val(pud) & _REGION3_ENTRY_LARGE);
}

static inline unsigned long pud_pfn(pud_t pud)
{
	unsigned long origin_mask;

	origin_mask = _REGION_ENTRY_ORIGIN;
	if (pud_large(pud))
		origin_mask = _REGION3_ENTRY_ORIGIN_LARGE;
	return (pud_val(pud) & origin_mask) >> PAGE_SHIFT;
}

static inline int pmd_large(pmd_t pmd)
{
	return (pmd_val(pmd) & _SEGMENT_ENTRY_LARGE) != 0;
}

static inline int pmd_bad(pmd_t pmd)
{
	if (pmd_large(pmd))
		return (pmd_val(pmd) & ~_SEGMENT_ENTRY_BITS_LARGE) != 0;
	return (pmd_val(pmd) & ~_SEGMENT_ENTRY_BITS) != 0;
}

static inline int pud_bad(pud_t pud)
{
	if ((pud_val(pud) & _REGION_ENTRY_TYPE_MASK) < _REGION_ENTRY_TYPE_R3)
		return pmd_bad(__pmd(pud_val(pud)));
	if (pud_large(pud))
		return (pud_val(pud) & ~_REGION_ENTRY_BITS_LARGE) != 0;
	return (pud_val(pud) & ~_REGION_ENTRY_BITS) != 0;
}

static inline int p4d_bad(p4d_t p4d)
{
	if ((p4d_val(p4d) & _REGION_ENTRY_TYPE_MASK) < _REGION_ENTRY_TYPE_R2)
		return pud_bad(__pud(p4d_val(p4d)));
	return (p4d_val(p4d) & ~_REGION_ENTRY_BITS) != 0;
}

static inline int pmd_present(pmd_t pmd)
{
	return pmd_val(pmd) != _SEGMENT_ENTRY_EMPTY;
}

static inline int pmd_none(pmd_t pmd)
{
	return pmd_val(pmd) == _SEGMENT_ENTRY_EMPTY;
}

static inline unsigned long pmd_pfn(pmd_t pmd)
{
	unsigned long origin_mask;

	origin_mask = _SEGMENT_ENTRY_ORIGIN;
	if (pmd_large(pmd))
		origin_mask = _SEGMENT_ENTRY_ORIGIN_LARGE;
	return (pmd_val(pmd) & origin_mask) >> PAGE_SHIFT;
}

#define __HAVE_ARCH_PMD_WRITE
static inline int pmd_write(pmd_t pmd)
{
	return (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) != 0;
}

static inline int pmd_dirty(pmd_t pmd)
{
	int dirty = 1;
	if (pmd_large(pmd))
		dirty = (pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY) != 0;
	return dirty;
}

static inline int pmd_young(pmd_t pmd)
{
	int young = 1;
	if (pmd_large(pmd))
		young = (pmd_val(pmd) & _SEGMENT_ENTRY_YOUNG) != 0;
	return young;
}

static inline int pte_present(pte_t pte)
{
	/* Bit pattern: (pte & 0x001) == 0x001 */
	return (pte_val(pte) & _PAGE_PRESENT) != 0;
}

static inline int pte_none(pte_t pte)
{
	/* Bit pattern: pte == 0x400 */
	return pte_val(pte) == _PAGE_INVALID;
}

static inline int pte_swap(pte_t pte)
{
	/* Bit pattern: (pte & 0x201) == 0x200 */
	return (pte_val(pte) & (_PAGE_PROTECT | _PAGE_PRESENT))
		== _PAGE_PROTECT;
}

static inline int pte_special(pte_t pte)
{
	return (pte_val(pte) & _PAGE_SPECIAL);
}

#define __HAVE_ARCH_PTE_SAME
static inline int pte_same(pte_t a, pte_t b)
{
	return pte_val(a) == pte_val(b);
}

#ifdef CONFIG_NUMA_BALANCING
static inline int pte_protnone(pte_t pte)
{
	return pte_present(pte) && !(pte_val(pte) & _PAGE_READ);
}

static inline int pmd_protnone(pmd_t pmd)
{
	/* pmd_large(pmd) implies pmd_present(pmd) */
	return pmd_large(pmd) && !(pmd_val(pmd) & _SEGMENT_ENTRY_READ);
}
#endif

static inline int pte_soft_dirty(pte_t pte)
{
	return pte_val(pte) & _PAGE_SOFT_DIRTY;
}
#define pte_swp_soft_dirty pte_soft_dirty

static inline pte_t pte_mksoft_dirty(pte_t pte)
{
	pte_val(pte) |= _PAGE_SOFT_DIRTY;
	return pte;
}
#define pte_swp_mksoft_dirty pte_mksoft_dirty

static inline pte_t pte_clear_soft_dirty(pte_t pte)
{
	pte_val(pte) &= ~_PAGE_SOFT_DIRTY;
	return pte;
}
#define pte_swp_clear_soft_dirty pte_clear_soft_dirty

static inline int pmd_soft_dirty(pmd_t pmd)
{
	return pmd_val(pmd) & _SEGMENT_ENTRY_SOFT_DIRTY;
}

static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
{
	pmd_val(pmd) |= _SEGMENT_ENTRY_SOFT_DIRTY;
	return pmd;
}

static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd)
{
	pmd_val(pmd) &= ~_SEGMENT_ENTRY_SOFT_DIRTY;
	return pmd;
}

/*
 * query functions pte_write/pte_dirty/pte_young only work if
 * pte_present() is true. Undefined behaviour if not..
 */
static inline int pte_write(pte_t pte)
{
	return (pte_val(pte) & _PAGE_WRITE) != 0;
}

static inline int pte_dirty(pte_t pte)
{
	return (pte_val(pte) & _PAGE_DIRTY) != 0;
}

static inline int pte_young(pte_t pte)
{
	return (pte_val(pte) & _PAGE_YOUNG) != 0;
}

#define __HAVE_ARCH_PTE_UNUSED
static inline int pte_unused(pte_t pte)
{
	return pte_val(pte) & _PAGE_UNUSED;
}

/*
 * pgd/pmd/pte modification functions
 */

static inline void pgd_clear(pgd_t *pgd)
{
	if ((pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R1)
		pgd_val(*pgd) = _REGION1_ENTRY_EMPTY;
}

static inline void p4d_clear(p4d_t *p4d)
{
	if ((p4d_val(*p4d) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2)
		p4d_val(*p4d) = _REGION2_ENTRY_EMPTY;
}

static inline void pud_clear(pud_t *pud)
{
	if ((pud_val(*pud) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
		pud_val(*pud) = _REGION3_ENTRY_EMPTY;
}

static inline void pmd_clear(pmd_t *pmdp)
{
	pmd_val(*pmdp) = _SEGMENT_ENTRY_EMPTY;
}

static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
	pte_val(*ptep) = _PAGE_INVALID;
}

/*
 * The following pte modification functions only work if
 * pte_present() is true. Undefined behaviour if not..
 */
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
	pte_val(pte) &= _PAGE_CHG_MASK;
	pte_val(pte) |= pgprot_val(newprot);
	/*
	 * newprot for PAGE_NONE, PAGE_RO, PAGE_RX, PAGE_RW and PAGE_RWX
	 * has the invalid bit set, clear it again for readable, young pages
	 */
	if ((pte_val(pte) & _PAGE_YOUNG) && (pte_val(pte) & _PAGE_READ))
		pte_val(pte) &= ~_PAGE_INVALID;
	/*
	 * newprot for PAGE_RO, PAGE_RX, PAGE_RW and PAGE_RWX has the page
	 * protection bit set, clear it again for writable, dirty pages
	 */
	if ((pte_val(pte) & _PAGE_DIRTY) && (pte_val(pte) & _PAGE_WRITE))
		pte_val(pte) &= ~_PAGE_PROTECT;
	return pte;
}

static inline pte_t pte_wrprotect(pte_t pte)
{
	pte_val(pte) &= ~_PAGE_WRITE;
	pte_val(pte) |= _PAGE_PROTECT;
	return pte;
}

static inline pte_t pte_mkwrite(pte_t pte)
{
	pte_val(pte) |= _PAGE_WRITE;
	if (pte_val(pte) & _PAGE_DIRTY)
		pte_val(pte) &= ~_PAGE_PROTECT;
	return pte;
}

static inline pte_t pte_mkclean(pte_t pte)
{
	pte_val(pte) &= ~_PAGE_DIRTY;
	pte_val(pte) |= _PAGE_PROTECT;
	return pte;
}

static inline pte_t pte_mkdirty(pte_t pte)
{
	pte_val(pte) |= _PAGE_DIRTY | _PAGE_SOFT_DIRTY;
	if (pte_val(pte) & _PAGE_WRITE)
		pte_val(pte) &= ~_PAGE_PROTECT;
	return pte;
}

static inline pte_t pte_mkold(pte_t pte)
{
	pte_val(pte) &= ~_PAGE_YOUNG;
	pte_val(pte) |= _PAGE_INVALID;
	return pte;
}

static inline pte_t pte_mkyoung(pte_t pte)
{
	pte_val(pte) |= _PAGE_YOUNG;
	if (pte_val(pte) & _PAGE_READ)
		pte_val(pte) &= ~_PAGE_INVALID;
	return pte;
}

static inline pte_t pte_mkspecial(pte_t pte)
{
	pte_val(pte) |= _PAGE_SPECIAL;
	return pte;
}

#ifdef CONFIG_HUGETLB_PAGE
static inline pte_t pte_mkhuge(pte_t pte)
{
	pte_val(pte) |= _PAGE_LARGE;
	return pte;
}
#endif

#define IPTE_GLOBAL	0
#define	IPTE_LOCAL	1

static inline void __ptep_ipte(unsigned long address, pte_t *ptep, int local)
{
	unsigned long pto = (unsigned long) ptep;

	/* Invalidation + TLB flush for the pte */
	asm volatile(
		"       .insn rrf,0xb2210000,%[r1],%[r2],0,%[m4]"
		: "+m" (*ptep) : [r1] "a" (pto), [r2] "a" (address),
		  [m4] "i" (local));
}

static inline void __ptep_ipte_range(unsigned long address, int nr,
				     pte_t *ptep, int local)
{
	unsigned long pto = (unsigned long) ptep;

	/* Invalidate a range of ptes + TLB flush of the ptes */
	do {
		asm volatile(
			"       .insn rrf,0xb2210000,%[r1],%[r2],%[r3],%[m4]"
			: [r2] "+a" (address), [r3] "+a" (nr)
			: [r1] "a" (pto), [m4] "i" (local) : "memory");
	} while (nr != 255);
}

/*
 * This is hard to understand. ptep_get_and_clear and ptep_clear_flush
 * both clear the TLB for the unmapped pte. The reason is that
 * ptep_get_and_clear is used in common code (e.g. change_pte_range)
 * to modify an active pte. The sequence is
 *   1) ptep_get_and_clear
 *   2) set_pte_at
 *   3) flush_tlb_range
 * On s390 the tlb needs to get flushed with the modification of the pte
 * if the pte is active. The only way how this can be implemented is to
 * have ptep_get_and_clear do the tlb flush. In exchange flush_tlb_range
 * is a nop.
 */
pte_t ptep_xchg_direct(struct mm_struct *, unsigned long, pte_t *, pte_t);
pte_t ptep_xchg_lazy(struct mm_struct *, unsigned long, pte_t *, pte_t);

#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
					    unsigned long addr, pte_t *ptep)
{
	pte_t pte = *ptep;

	pte = ptep_xchg_direct(vma->vm_mm, addr, ptep, pte_mkold(pte));
	return pte_young(pte);
}

#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
					 unsigned long address, pte_t *ptep)
{
	return ptep_test_and_clear_young(vma, address, ptep);
}

#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
				       unsigned long addr, pte_t *ptep)
{
	return ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID));
}

#define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
pte_t ptep_modify_prot_start(struct mm_struct *, unsigned long, pte_t *);
void ptep_modify_prot_commit(struct mm_struct *, unsigned long, pte_t *, pte_t);

#define __HAVE_ARCH_PTEP_CLEAR_FLUSH
static inline pte_t ptep_clear_flush(struct vm_area_struct *vma,
				     unsigned long addr, pte_t *ptep)
{
	return ptep_xchg_direct(vma->vm_mm, addr, ptep, __pte(_PAGE_INVALID));
}

/*
 * The batched pte unmap code uses ptep_get_and_clear_full to clear the
 * ptes. Here an optimization is possible. tlb_gather_mmu flushes all
 * tlbs of an mm if it can guarantee that the ptes of the mm_struct
 * cannot be accessed while the batched unmap is running. In this case
 * full==1 and a simple pte_clear is enough. See tlb.h.
 */
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
					    unsigned long addr,
					    pte_t *ptep, int full)
{
	if (full) {
		pte_t pte = *ptep;
		*ptep = __pte(_PAGE_INVALID);
		return pte;
	}
	return ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID));
}

#define __HAVE_ARCH_PTEP_SET_WRPROTECT
static inline void ptep_set_wrprotect(struct mm_struct *mm,
				      unsigned long addr, pte_t *ptep)
{
	pte_t pte = *ptep;

	if (pte_write(pte))
		ptep_xchg_lazy(mm, addr, ptep, pte_wrprotect(pte));
}

#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
static inline int ptep_set_access_flags(struct vm_area_struct *vma,
					unsigned long addr, pte_t *ptep,
					pte_t entry, int dirty)
{
	if (pte_same(*ptep, entry))
		return 0;
	ptep_xchg_direct(vma->vm_mm, addr, ptep, entry);
	return 1;
}

/*
 * Additional functions to handle KVM guest page tables
 */
void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
		     pte_t *ptep, pte_t entry);
void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
void ptep_notify(struct mm_struct *mm, unsigned long addr,
		 pte_t *ptep, unsigned long bits);
int ptep_force_prot(struct mm_struct *mm, unsigned long gaddr,
		    pte_t *ptep, int prot, unsigned long bit);
void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
		     pte_t *ptep , int reset);
void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
		    pte_t *sptep, pte_t *tptep, pte_t pte);
void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep);

bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long address);
int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
			  unsigned char key, bool nq);
int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
			       unsigned char key, unsigned char *oldkey,
			       bool nq, bool mr, bool mc);
int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr);
int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
			  unsigned char *key);

int set_pgste_bits(struct mm_struct *mm, unsigned long addr,
				unsigned long bits, unsigned long value);
int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep);
int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
			unsigned long *oldpte, unsigned long *oldpgste);

/*
 * Certain architectures need to do special things when PTEs
 * within a page table are directly modified.  Thus, the following
 * hook is made available.
 */
static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
			      pte_t *ptep, pte_t entry)
{
	if (!MACHINE_HAS_NX)
		pte_val(entry) &= ~_PAGE_NOEXEC;
	if (pte_present(entry))
		pte_val(entry) &= ~_PAGE_UNUSED;
	if (mm_has_pgste(mm))
		ptep_set_pte_at(mm, addr, ptep, entry);
	else
		*ptep = entry;
}

/*
 * Conversion functions: convert a page and protection to a page entry,
 * and a page entry and page directory to the page they refer to.
 */
static inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
{
	pte_t __pte;
	pte_val(__pte) = physpage + pgprot_val(pgprot);
	return pte_mkyoung(__pte);
}

static inline pte_t mk_pte(struct page *page, pgprot_t pgprot)
{
	unsigned long physpage = page_to_phys(page);
	pte_t __pte = mk_pte_phys(physpage, pgprot);

	if (pte_write(__pte) && PageDirty(page))
		__pte = pte_mkdirty(__pte);
	return __pte;
}

#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
#define p4d_index(address) (((address) >> P4D_SHIFT) & (PTRS_PER_P4D-1))
#define pud_index(address) (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
#define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
#define pte_index(address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE-1))

#define pgd_offset(mm, address) ((mm)->pgd + pgd_index(address))
#define pgd_offset_k(address) pgd_offset(&init_mm, address)

#define pmd_deref(pmd) (pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN)
#define pud_deref(pud) (pud_val(pud) & _REGION_ENTRY_ORIGIN)
#define p4d_deref(pud) (p4d_val(pud) & _REGION_ENTRY_ORIGIN)
#define pgd_deref(pgd) (pgd_val(pgd) & _REGION_ENTRY_ORIGIN)

static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
{
	p4d_t *p4d = (p4d_t *) pgd;

	if ((pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R1)
		p4d = (p4d_t *) pgd_deref(*pgd);
	return p4d + p4d_index(address);
}

static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address)
{
	pud_t *pud = (pud_t *) p4d;

	if ((p4d_val(*p4d) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2)
		pud = (pud_t *) p4d_deref(*p4d);
	return pud + pud_index(address);
}

static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
	pmd_t *pmd = (pmd_t *) pud;

	if ((pud_val(*pud) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
		pmd = (pmd_t *) pud_deref(*pud);
	return pmd + pmd_index(address);
}

#define pfn_pte(pfn,pgprot) mk_pte_phys(__pa((pfn) << PAGE_SHIFT),(pgprot))
#define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT)
#define pte_page(x) pfn_to_page(pte_pfn(x))

#define pmd_page(pmd) pfn_to_page(pmd_pfn(pmd))
#define pud_page(pud) pfn_to_page(pud_pfn(pud))
#define p4d_page(pud) pfn_to_page(p4d_pfn(p4d))

/* Find an entry in the lowest level page table.. */
#define pte_offset(pmd, addr) ((pte_t *) pmd_deref(*(pmd)) + pte_index(addr))
#define pte_offset_kernel(pmd, address) pte_offset(pmd,address)
#define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)
#define pte_unmap(pte) do { } while (0)

static inline pmd_t pmd_wrprotect(pmd_t pmd)
{
	pmd_val(pmd) &= ~_SEGMENT_ENTRY_WRITE;
	pmd_val(pmd) |= _SEGMENT_ENTRY_PROTECT;
	return pmd;
}

static inline pmd_t pmd_mkwrite(pmd_t pmd)
{
	pmd_val(pmd) |= _SEGMENT_ENTRY_WRITE;
	if (pmd_large(pmd) && !(pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY))
		return pmd;
	pmd_val(pmd) &= ~_SEGMENT_ENTRY_PROTECT;
	return pmd;
}

static inline pmd_t pmd_mkclean(pmd_t pmd)
{
	if (pmd_large(pmd)) {
		pmd_val(pmd) &= ~_SEGMENT_ENTRY_DIRTY;
		pmd_val(pmd) |= _SEGMENT_ENTRY_PROTECT;
	}
	return pmd;
}

static inline pmd_t pmd_mkdirty(pmd_t pmd)
{
	if (pmd_large(pmd)) {
		pmd_val(pmd) |= _SEGMENT_ENTRY_DIRTY |
				_SEGMENT_ENTRY_SOFT_DIRTY;
		if (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE)
			pmd_val(pmd) &= ~_SEGMENT_ENTRY_PROTECT;
	}
	return pmd;
}

static inline pud_t pud_wrprotect(pud_t pud)
{
	pud_val(pud) &= ~_REGION3_ENTRY_WRITE;
	pud_val(pud) |= _REGION_ENTRY_PROTECT;
	return pud;
}

static inline pud_t pud_mkwrite(pud_t pud)
{
	pud_val(pud) |= _REGION3_ENTRY_WRITE;
	if (pud_large(pud) && !(pud_val(pud) & _REGION3_ENTRY_DIRTY))
		return pud;
	pud_val(pud) &= ~_REGION_ENTRY_PROTECT;
	return pud;
}

static inline pud_t pud_mkclean(pud_t pud)
{
	if (pud_large(pud)) {
		pud_val(pud) &= ~_REGION3_ENTRY_DIRTY;
		pud_val(pud) |= _REGION_ENTRY_PROTECT;
	}
	return pud;
}

static inline pud_t pud_mkdirty(pud_t pud)
{
	if (pud_large(pud)) {
		pud_val(pud) |= _REGION3_ENTRY_DIRTY |
				_REGION3_ENTRY_SOFT_DIRTY;
		if (pud_val(pud) & _REGION3_ENTRY_WRITE)
			pud_val(pud) &= ~_REGION_ENTRY_PROTECT;
	}
	return pud;
}

#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE)
static inline unsigned long massage_pgprot_pmd(pgprot_t pgprot)
{
	/*
	 * pgprot is PAGE_NONE, PAGE_RO, PAGE_RX, PAGE_RW or PAGE_RWX
	 * (see __Pxxx / __Sxxx). Convert to segment table entry format.
	 */
	if (pgprot_val(pgprot) == pgprot_val(PAGE_NONE))
		return pgprot_val(SEGMENT_NONE);
	if (pgprot_val(pgprot) == pgprot_val(PAGE_RO))
		return pgprot_val(SEGMENT_RO);
	if (pgprot_val(pgprot) == pgprot_val(PAGE_RX))
		return pgprot_val(SEGMENT_RX);
	if (pgprot_val(pgprot) == pgprot_val(PAGE_RW))
		return pgprot_val(SEGMENT_RW);
	return pgprot_val(SEGMENT_RWX);
}

static inline pmd_t pmd_mkyoung(pmd_t pmd)
{
	if (pmd_large(pmd)) {
		pmd_val(pmd) |= _SEGMENT_ENTRY_YOUNG;
		if (pmd_val(pmd) & _SEGMENT_ENTRY_READ)
			pmd_val(pmd) &= ~_SEGMENT_ENTRY_INVALID;
	}
	return pmd;
}

static inline pmd_t pmd_mkold(pmd_t pmd)
{
	if (pmd_large(pmd)) {
		pmd_val(pmd) &= ~_SEGMENT_ENTRY_YOUNG;
		pmd_val(pmd) |= _SEGMENT_ENTRY_INVALID;
	}
	return pmd;
}

static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
{
	if (pmd_large(pmd)) {
		pmd_val(pmd) &= _SEGMENT_ENTRY_ORIGIN_LARGE |
			_SEGMENT_ENTRY_DIRTY | _SEGMENT_ENTRY_YOUNG |
			_SEGMENT_ENTRY_LARGE | _SEGMENT_ENTRY_SOFT_DIRTY;
		pmd_val(pmd) |= massage_pgprot_pmd(newprot);
		if (!(pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY))
			pmd_val(pmd) |= _SEGMENT_ENTRY_PROTECT;
		if (!(pmd_val(pmd) & _SEGMENT_ENTRY_YOUNG))
			pmd_val(pmd) |= _SEGMENT_ENTRY_INVALID;
		return pmd;
	}
	pmd_val(pmd) &= _SEGMENT_ENTRY_ORIGIN;
	pmd_val(pmd) |= massage_pgprot_pmd(newprot);
	return pmd;
}

static inline pmd_t mk_pmd_phys(unsigned long physpage, pgprot_t pgprot)
{
	pmd_t __pmd;
	pmd_val(__pmd) = physpage + massage_pgprot_pmd(pgprot);
	return __pmd;
}

#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLB_PAGE */

static inline void __pmdp_csp(pmd_t *pmdp)
{
	csp((unsigned int *)pmdp + 1, pmd_val(*pmdp),
	    pmd_val(*pmdp) | _SEGMENT_ENTRY_INVALID);
}

#define IDTE_GLOBAL	0
#define IDTE_LOCAL	1

static inline void __pmdp_idte(unsigned long address, pmd_t *pmdp, int local)
{
	unsigned long sto;

	sto = (unsigned long) pmdp - pmd_index(address) * sizeof(pmd_t);
	asm volatile(
		"	.insn	rrf,0xb98e0000,%[r1],%[r2],0,%[m4]"
		: "+m" (*pmdp)
		: [r1] "a" (sto), [r2] "a" ((address & HPAGE_MASK)),
		  [m4] "i" (local)
		: "cc" );
}

static inline void __pudp_idte(unsigned long address, pud_t *pudp, int local)
{
	unsigned long r3o;

	r3o = (unsigned long) pudp - pud_index(address) * sizeof(pud_t);
	r3o |= _ASCE_TYPE_REGION3;
	asm volatile(
		"	.insn	rrf,0xb98e0000,%[r1],%[r2],0,%[m4]"
		: "+m" (*pudp)
		: [r1] "a" (r3o), [r2] "a" ((address & PUD_MASK)),
		  [m4] "i" (local)
		: "cc");
}

pmd_t pmdp_xchg_direct(struct mm_struct *, unsigned long, pmd_t *, pmd_t);
pmd_t pmdp_xchg_lazy(struct mm_struct *, unsigned long, pmd_t *, pmd_t);
pud_t pudp_xchg_direct(struct mm_struct *, unsigned long, pud_t *, pud_t);

#ifdef CONFIG_TRANSPARENT_HUGEPAGE

#define __HAVE_ARCH_PGTABLE_DEPOSIT
void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
				pgtable_t pgtable);

#define __HAVE_ARCH_PGTABLE_WITHDRAW
pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);

#define  __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
					unsigned long addr, pmd_t *pmdp,
					pmd_t entry, int dirty)
{
	VM_BUG_ON(addr & ~HPAGE_MASK);

	entry = pmd_mkyoung(entry);
	if (dirty)
		entry = pmd_mkdirty(entry);
	if (pmd_val(*pmdp) == pmd_val(entry))
		return 0;
	pmdp_xchg_direct(vma->vm_mm, addr, pmdp, entry);
	return 1;
}

#define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
					    unsigned long addr, pmd_t *pmdp)
{
	pmd_t pmd = *pmdp;

	pmd = pmdp_xchg_direct(vma->vm_mm, addr, pmdp, pmd_mkold(pmd));
	return pmd_young(pmd);
}

#define __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
					 unsigned long addr, pmd_t *pmdp)
{
	VM_BUG_ON(addr & ~HPAGE_MASK);
	return pmdp_test_and_clear_young(vma, addr, pmdp);
}

static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
			      pmd_t *pmdp, pmd_t entry)
{
	if (!MACHINE_HAS_NX)
		pmd_val(entry) &= ~_SEGMENT_ENTRY_NOEXEC;
	*pmdp = entry;
}

static inline pmd_t pmd_mkhuge(pmd_t pmd)
{
	pmd_val(pmd) |= _SEGMENT_ENTRY_LARGE;
	pmd_val(pmd) |= _SEGMENT_ENTRY_YOUNG;
	pmd_val(pmd) |= _SEGMENT_ENTRY_PROTECT;
	return pmd;
}

#define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
					    unsigned long addr, pmd_t *pmdp)
{
	return pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
}

#define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR_FULL
static inline pmd_t pmdp_huge_get_and_clear_full(struct mm_struct *mm,
						 unsigned long addr,
						 pmd_t *pmdp, int full)
{
	if (full) {
		pmd_t pmd = *pmdp;
		*pmdp = __pmd(_SEGMENT_ENTRY_EMPTY);
		return pmd;
	}
	return pmdp_xchg_lazy(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
}

#define __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
static inline pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
					  unsigned long addr, pmd_t *pmdp)
{
	return pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
}

#define __HAVE_ARCH_PMDP_INVALIDATE
static inline void pmdp_invalidate(struct vm_area_struct *vma,
				   unsigned long addr, pmd_t *pmdp)
{
	pmdp_xchg_direct(vma->vm_mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
}

#define __HAVE_ARCH_PMDP_SET_WRPROTECT
static inline void pmdp_set_wrprotect(struct mm_struct *mm,
				      unsigned long addr, pmd_t *pmdp)
{
	pmd_t pmd = *pmdp;

	if (pmd_write(pmd))
		pmd = pmdp_xchg_lazy(mm, addr, pmdp, pmd_wrprotect(pmd));
}

static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
					unsigned long address,
					pmd_t *pmdp)
{
	return pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
}
#define pmdp_collapse_flush pmdp_collapse_flush

#define pfn_pmd(pfn, pgprot)	mk_pmd_phys(__pa((pfn) << PAGE_SHIFT), (pgprot))
#define mk_pmd(page, pgprot)	pfn_pmd(page_to_pfn(page), (pgprot))

static inline int pmd_trans_huge(pmd_t pmd)
{
	return pmd_val(pmd) & _SEGMENT_ENTRY_LARGE;
}

#define has_transparent_hugepage has_transparent_hugepage
static inline int has_transparent_hugepage(void)
{
	return MACHINE_HAS_EDAT1 ? 1 : 0;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

/*
 * 64 bit swap entry format:
 * A page-table entry has some bits we have to treat in a special way.
 * Bits 52 and bit 55 have to be zero, otherwise a specification
 * exception will occur instead of a page translation exception. The
 * specification exception has the bad habit not to store necessary
 * information in the lowcore.
 * Bits 54 and 63 are used to indicate the page type.
 * A swap pte is indicated by bit pattern (pte & 0x201) == 0x200
 * This leaves the bits 0-51 and bits 56-62 to store type and offset.
 * We use the 5 bits from 57-61 for the type and the 52 bits from 0-51
 * for the offset.
 * |			  offset			|01100|type |00|
 * |0000000000111111111122222222223333333333444444444455|55555|55566|66|
 * |0123456789012345678901234567890123456789012345678901|23456|78901|23|
 */

#define __SWP_OFFSET_MASK	((1UL << 52) - 1)
#define __SWP_OFFSET_SHIFT	12
#define __SWP_TYPE_MASK		((1UL << 5) - 1)
#define __SWP_TYPE_SHIFT	2

static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
{
	pte_t pte;

	pte_val(pte) = _PAGE_INVALID | _PAGE_PROTECT;
	pte_val(pte) |= (offset & __SWP_OFFSET_MASK) << __SWP_OFFSET_SHIFT;
	pte_val(pte) |= (type & __SWP_TYPE_MASK) << __SWP_TYPE_SHIFT;
	return pte;
}

static inline unsigned long __swp_type(swp_entry_t entry)
{
	return (entry.val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK;
}

static inline unsigned long __swp_offset(swp_entry_t entry)
{
	return (entry.val >> __SWP_OFFSET_SHIFT) & __SWP_OFFSET_MASK;
}

static inline swp_entry_t __swp_entry(unsigned long type, unsigned long offset)
{
	return (swp_entry_t) { pte_val(mk_swap_pte(type, offset)) };
}

#define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x)	((pte_t) { (x).val })

#endif /* !__ASSEMBLY__ */

#define kern_addr_valid(addr)   (1)

extern int vmem_add_mapping(unsigned long start, unsigned long size);
extern int vmem_remove_mapping(unsigned long start, unsigned long size);
extern int s390_enable_sie(void);
extern int s390_enable_skey(void);
extern void s390_reset_cmma(struct mm_struct *mm);

/* s390 has a private copy of get unmapped area to deal with cache synonyms */
#define HAVE_ARCH_UNMAPPED_AREA
#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN

/*
 * No page table caches to initialise
 */
static inline void pgtable_cache_init(void) { }
static inline void check_pgt_cache(void) { }

#include <asm-generic/pgtable.h>

#endif /* _S390_PAGE_H */