/*
* include/asm-s390/pgtable.h
*
* S390 version
* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
* 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 31 bit we "fold" the mid level into the top-level page table, so
* that we physically have the same two-level page table as the s390 mmu
* expects in 31 bit mode. For s390 64 bit we use three of the five levels
* the hardware provides (region first and region second 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 <asm/bug.h>
#include <asm/page.h>
extern pgd_t swapper_pg_dir[] __attribute__ ((aligned (4096)));
extern void paging_init(void);
extern void vmem_map_init(void);
extern void fault_init(void);
/*
* 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)
/*
* 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 is_zero_pfn is_zero_pfn
static inline int is_zero_pfn(unsigned long pfn)
{
extern unsigned long zero_pfn;
unsigned long offset_from_zero_pfn = pfn - zero_pfn;
return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
}
#define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr))
#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
*/
#ifndef __s390x__
# define PMD_SHIFT 20
# define PUD_SHIFT 20
# define PGDIR_SHIFT 20
#else /* __s390x__ */
# define PMD_SHIFT 20
# define PUD_SHIFT 31
# define PGDIR_SHIFT 42
#endif /* __s390x__ */
#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 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
#ifndef __s390x__
#define PTRS_PER_PMD 1
#define PTRS_PER_PUD 1
#else /* __s390x__ */
#define PTRS_PER_PMD 2048
#define PTRS_PER_PUD 2048
#endif /* __s390x__ */
#define PTRS_PER_PGD 2048
#define FIRST_USER_ADDRESS 0
#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 pgd_ERROR(e) \
printk("%s:%d: bad pgd %p.\n", __FILE__, __LINE__, (void *) pgd_val(e))
#ifndef __ASSEMBLY__
/*
* The vmalloc area will always be on the topmost area of the kernel
* mapping. We reserve 96MB (31bit) / 128GB (64bit) for vmalloc,
* which should be enough for any sane case.
* By putting vmalloc at the top, we maximise the gap between physical
* memory and vmalloc to catch misplaced memory accesses. As a side
* effect, this also makes sure that 64 bit module code cannot be used
* as system call address.
*/
extern unsigned long VMALLOC_START;
#ifndef __s390x__
#define VMALLOC_SIZE (96UL << 20)
#define VMALLOC_END 0x7e000000UL
#define VMEM_MAP_END 0x80000000UL
#else /* __s390x__ */
#define VMALLOC_SIZE (128UL << 30)
#define VMALLOC_END 0x3e000000000UL
#define VMEM_MAP_END 0x40000000000UL
#endif /* __s390x__ */
/*
* VMEM_MAX_PHYS is the highest physical address that can be added to the 1:1
* mapping. This needs to be calculated at compile time since the size of the
* VMEM_MAP is static but the size of struct page can change.
*/
#define VMEM_MAX_PAGES ((VMEM_MAP_END - VMALLOC_END) / sizeof(struct page))
#define VMEM_MAX_PFN min(VMALLOC_START >> PAGE_SHIFT, VMEM_MAX_PAGES)
#define VMEM_MAX_PHYS ((VMEM_MAX_PFN << PAGE_SHIFT) & ~((16 << 20) - 1))
#define vmemmap ((struct page *) VMALLOC_END)
/*
* A 31 bit pagetable entry of S390 has following format:
* | PFRA | | OS |
* 0 0IP0
* 00000000001111111111222222222233
* 01234567890123456789012345678901
*
* I Page-Invalid Bit: Page is not available for address-translation
* P Page-Protection Bit: Store access not possible for page
*
* A 31 bit segmenttable entry of S390 has following format:
* | P-table origin | |PTL
* 0 IC
* 00000000001111111111222222222233
* 01234567890123456789012345678901
*
* I Segment-Invalid Bit: Segment is not available for address-translation
* C Common-Segment Bit: Segment is not private (PoP 3-30)
* PTL Page-Table-Length: Page-table length (PTL+1*16 entries -> up to 256)
*
* The 31 bit segmenttable origin of S390 has following format:
*
* |S-table origin | | STL |
* X **GPS
* 00000000001111111111222222222233
* 01234567890123456789012345678901
*
* X Space-Switch event:
* G Segment-Invalid Bit: *
* P Private-Space Bit: Segment is not private (PoP 3-30)
* S Storage-Alteration:
* STL Segment-Table-Length: Segment-table length (STL+1*16 entries -> up to 2048)
*
* 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