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kernel-ark/include/asm-s390/pgtable.h
Martin Schwidefsky 0d01792300 [S390] pud_present/pmd_present bug. 
Git commit 3610cce87a (yeah my own :-/)
introduced a bug in regard to pud/pmd table entries.
If the address of the page table refered to by a pud/pmd value happens
to have zeroes in the lower 32 bits, pud_present and pmd_present return
false. The obvious effect is that this triggers the BUG_ON in exit_mmap
because some ptes will not get released on process end.  Worse is that
the next fault for memory covered by that pud/pmd will allocate another
pmd/pte table and populate the pud/pmd entry. The old page table
entries hanging below this entry are lost!

The fix is simple, properly check against 0. The check is added for
pud_none/pmd_none as well even if these two functions work because
the invalid bit is in the lower 32 bits.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-12-17 16:25:56 +01:00

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/*
* 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/mm_types.h>
#include <asm/bug.h>
#include <asm/processor.h>
extern pgd_t swapper_pg_dir[] __attribute__ ((aligned (4096)));
extern void paging_init(void);
extern void vmem_map_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, pte) do { } while (0)
/*
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..
*/
extern char empty_zero_page[PAGE_SIZE];
#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
#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 22
# define PUD_SHIFT 22
# define PGDIR_SHIFT 22
#else /* __s390x__ */
# define PMD_SHIFT 21
# define PUD_SHIFT 31
# define PGDIR_SHIFT 31
#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
*/
#ifndef __s390x__
# define PTRS_PER_PTE 1024
# define PTRS_PER_PMD 1
# define PTRS_PER_PUD 1
# define PTRS_PER_PGD 512
#else /* __s390x__ */
# define PTRS_PER_PTE 512
# define PTRS_PER_PMD 1024
# define PTRS_PER_PUD 1
# define PTRS_PER_PGD 2048
#endif /* __s390x__ */
#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__
/*
* Just any arbitrary offset to the start of the vmalloc VM area: the
* current 8MB value just means that there will be a 8MB "hole" after the
* physical memory until the kernel virtual memory starts. That means that
* any out-of-bounds memory accesses will hopefully be caught.
* The vmalloc() routines leaves a hole of 4kB between each vmalloced
* area for the same reason. ;)
* vmalloc area starts at 4GB to prevent syscall table entry exchanging
* from modules.
*/
extern unsigned long vmalloc_end;
#ifdef CONFIG_64BIT
#define VMALLOC_ADDR (max(0x100000000UL, (unsigned long) high_memory))
#else
#define VMALLOC_ADDR ((unsigned long) high_memory)
#endif
#define VMALLOC_OFFSET (8*1024*1024)
#define VMALLOC_START ((VMALLOC_ADDR + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
#define VMALLOC_END vmalloc_end
/*
* We need some free virtual space to be able to do vmalloc.
* VMALLOC_MIN_SIZE defines the minimum size of the vmalloc
* area. On a machine with 2GB memory we make sure that we
* have at least 128MB free space for vmalloc. On a machine
* with 4TB we make sure we have at least 128GB.
*/
#ifndef __s390x__
#define VMALLOC_MIN_SIZE 0x8000000UL
#define VMALLOC_END_INIT 0x80000000UL
#else /* __s390x__ */
#define VMALLOC_MIN_SIZE 0x2000000000UL
#define VMALLOC_END_INIT 0x40000000000UL
#endif /* __s390x__ */
/*
* 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 |0IP0| OS |
* 0000000000111111111122222222223333333333444444444455555555556666
* 0123456789012345678901234567890123456789012345678901234567890123
*
* I Page-Invalid Bit: Page is not available for address-translation
* P Page-Protection Bit: Store access not possible for page
*
* 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_RO 0x200 /* HW read-only bit */
#define _PAGE_INVALID 0x400 /* HW invalid bit */
/* Software bits in the page table entry */
#define _PAGE_SWT 0x001 /* SW pte type bit t */
#define _PAGE_SWX 0x002 /* SW pte type bit x */
/* Six different types of pages. */
#define _PAGE_TYPE_EMPTY 0x400
#define _PAGE_TYPE_NONE 0x401
#define _PAGE_TYPE_SWAP 0x403
#define _PAGE_TYPE_FILE 0x601 /* bit 0x002 is used for offset !! */
#define _PAGE_TYPE_RO 0x200
#define _PAGE_TYPE_RW 0x000
#define _PAGE_TYPE_EX_RO 0x202
#define _PAGE_TYPE_EX_RW 0x002
/*
* PTE type bits are rather complicated. handle_pte_fault uses pte_present,
* pte_none and pte_file to find out the pte type WITHOUT holding the page
* table lock. ptep_clear_flush on the other hand uses ptep_clear_flush to
* invalidate a given pte. ipte sets the hw invalid bit and clears all tlbs
* for the page. The page table entry is set to _PAGE_TYPE_EMPTY afterwards.
* This change is done while holding the lock, but the intermediate step
* of a previously valid pte with the hw invalid bit set can be observed by
* handle_pte_fault. That makes it necessary that all valid pte types with
* the hw invalid bit set must be distinguishable from the four pte types
* empty, none, swap and file.
*
* irxt ipte irxt
* _PAGE_TYPE_EMPTY 1000 -> 1000
* _PAGE_TYPE_NONE 1001 -> 1001
* _PAGE_TYPE_SWAP 1011 -> 1011
* _PAGE_TYPE_FILE 11?1 -> 11?1
* _PAGE_TYPE_RO 0100 -> 1100
* _PAGE_TYPE_RW 0000 -> 1000
* _PAGE_TYPE_EX_RO 0110 -> 1110
* _PAGE_TYPE_EX_RW 0010 -> 1010
*
* pte_none is true for bits combinations 1000, 1010, 1100, 1110
* pte_present is true for bits combinations 0000, 0010, 0100, 0110, 1001
* pte_file is true for bits combinations 1101, 1111
* swap pte is 1011 and 0001, 0011, 0101, 0111 are invalid.
*/
#ifndef __s390x__
/* Bits in the segment table address-space-control-element */
#define _ASCE_SPACE_SWITCH 0x80000000UL /* space switch event */
#define _ASCE_ORIGIN_MASK 0x7ffff000UL /* segment table origin */
#define _ASCE_PRIVATE_SPACE 0x100 /* private space control */
#define _ASCE_ALT_EVENT 0x80 /* storage alteration event control */
#define _ASCE_TABLE_LENGTH 0x7f /* 128 x 64 entries = 8k */
/* Bits in the segment table entry */
#define _SEGMENT_ENTRY_ORIGIN 0x7fffffc0UL /* page table origin */
#define _SEGMENT_ENTRY_INV 0x20 /* invalid segment table entry */
#define _SEGMENT_ENTRY_COMMON 0x10 /* common segment bit */
#define _SEGMENT_ENTRY_PTL 0x0f /* page table length */
#define _SEGMENT_ENTRY (_SEGMENT_ENTRY_PTL)
#define _SEGMENT_ENTRY_EMPTY (_SEGMENT_ENTRY_INV)
#else /* __s390x__ */
/* 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_INV 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_INV)
#define _REGION2_ENTRY (_REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_LENGTH)
#define _REGION2_ENTRY_EMPTY (_REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INV)
#define _REGION3_ENTRY (_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_LENGTH)
#define _REGION3_ENTRY_EMPTY (_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INV)
/* Bits in the segment table entry */
#define _SEGMENT_ENTRY_ORIGIN ~0x7ffUL/* segment table origin */
#define _SEGMENT_ENTRY_RO 0x200 /* page protection bit */
#define _SEGMENT_ENTRY_INV 0x20 /* invalid segment table entry */
#define _SEGMENT_ENTRY (0)
#define _SEGMENT_ENTRY_EMPTY (_SEGMENT_ENTRY_INV)
#endif /* __s390x__ */
/*
* 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)
/* Bits int the storage key */
#define _PAGE_CHANGED 0x02 /* HW changed bit */
#define _PAGE_REFERENCED 0x04 /* HW referenced bit */
/*
* Page protection definitions.
*/
#define PAGE_NONE __pgprot(_PAGE_TYPE_NONE)
#define PAGE_RO __pgprot(_PAGE_TYPE_RO)
#define PAGE_RW __pgprot(_PAGE_TYPE_RW)
#define PAGE_EX_RO __pgprot(_PAGE_TYPE_EX_RO)
#define PAGE_EX_RW __pgprot(_PAGE_TYPE_EX_RW)
#define PAGE_KERNEL PAGE_RW
#define PAGE_COPY PAGE_RO
/*
* Dependent on the EXEC_PROTECT option s390 can do execute protection.
* Write permission always implies read permission. In theory with a
* primary/secondary page table execute only can be implemented but
* it would cost an additional bit in the pte to distinguish all the
* different pte types. To avoid that execute permission currently
* implies read permission as well.
*/
/*xwr*/
#define __P000 PAGE_NONE
#define __P001 PAGE_RO
#define __P010 PAGE_RO
#define __P011 PAGE_RO
#define __P100 PAGE_EX_RO
#define __P101 PAGE_EX_RO
#define __P110 PAGE_EX_RO
#define __P111 PAGE_EX_RO
#define __S000 PAGE_NONE
#define __S001 PAGE_RO
#define __S010 PAGE_RW
#define __S011 PAGE_RW
#define __S100 PAGE_EX_RO
#define __S101 PAGE_EX_RO
#define __S110 PAGE_EX_RW
#define __S111 PAGE_EX_RW
#ifndef __s390x__
# define PxD_SHADOW_SHIFT 1
#else /* __s390x__ */
# define PxD_SHADOW_SHIFT 2
#endif /* __s390x__ */
static inline struct page *get_shadow_page(struct page *page)
{
if (s390_noexec && page->index)
return virt_to_page((void *)(addr_t) page->index);
return NULL;
}
static inline void *get_shadow_pte(void *table)
{
unsigned long addr, offset;
struct page *page;
addr = (unsigned long) table;
offset = addr & (PAGE_SIZE - 1);
page = virt_to_page((void *)(addr ^ offset));
return (void *)(addr_t)(page->index ? (page->index | offset) : 0UL);
}
static inline void *get_shadow_table(void *table)
{
unsigned long addr, offset;
struct page *page;
addr = (unsigned long) table;
offset = addr & ((PAGE_SIZE << PxD_SHADOW_SHIFT) - 1);
page = virt_to_page((void *)(addr ^ offset));
return (void *)(addr_t)(page->index ? (page->index | offset) : 0UL);
}
/*
* 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 *pteptr, pte_t pteval)
{
pte_t *shadow_pte = get_shadow_pte(pteptr);
*pteptr = pteval;
if (shadow_pte) {
if (!(pte_val(pteval) & _PAGE_INVALID) &&
(pte_val(pteval) & _PAGE_SWX))
pte_val(*shadow_pte) = pte_val(pteval) | _PAGE_RO;
else
pte_val(*shadow_pte) = _PAGE_TYPE_EMPTY;
}
}
/*
* pgd/pmd/pte query functions
*/
#ifndef __s390x__
static inline int pgd_present(pgd_t pgd) { return 1; }
static inline int pgd_none(pgd_t pgd) { return 0; }
static inline int pgd_bad(pgd_t pgd) { return 0; }
static inline int pud_present(pud_t pud) { return 1; }
static inline int pud_none(pud_t pud) { return 0; }
static inline int pud_bad(pud_t pud) { return 0; }
#else /* __s390x__ */
static inline int pgd_present(pgd_t pgd) { return 1; }
static inline int pgd_none(pgd_t pgd) { return 0; }
static inline int pgd_bad(pgd_t pgd) { return 0; }
static inline int pud_present(pud_t pud)
{
return (pud_val(pud) & _REGION_ENTRY_ORIGIN) != 0UL;
}
static inline int pud_none(pud_t pud)
{
return (pud_val(pud) & _REGION_ENTRY_INV) != 0UL;
}
static inline int pud_bad(pud_t pud)
{
unsigned long mask = ~_REGION_ENTRY_ORIGIN & ~_REGION_ENTRY_INV;
return (pud_val(pud) & mask) != _REGION3_ENTRY;
}
#endif /* __s390x__ */
static inline int pmd_present(pmd_t pmd)
{
return (pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN) != 0UL;
}
static inline int pmd_none(pmd_t pmd)
{
return (pmd_val(pmd) & _SEGMENT_ENTRY_INV) != 0UL;
}
static inline int pmd_bad(pmd_t pmd)
{
unsigned long mask = ~_SEGMENT_ENTRY_ORIGIN & ~_SEGMENT_ENTRY_INV;
return (pmd_val(pmd) & mask) != _SEGMENT_ENTRY;
}
static inline int pte_none(pte_t pte)
{
return (pte_val(pte) & _PAGE_INVALID) && !(pte_val(pte) & _PAGE_SWT);
}
static inline int pte_present(pte_t pte)
{
unsigned long mask = _PAGE_RO | _PAGE_INVALID | _PAGE_SWT | _PAGE_SWX;
return (pte_val(pte) & mask) == _PAGE_TYPE_NONE ||
(!(pte_val(pte) & _PAGE_INVALID) &&
!(pte_val(pte) & _PAGE_SWT));
}
static inline int pte_file(pte_t pte)
{
unsigned long mask = _PAGE_RO | _PAGE_INVALID | _PAGE_SWT;
return (pte_val(pte) & mask) == _PAGE_TYPE_FILE;
}
#define __HAVE_ARCH_PTE_SAME
#define pte_same(a,b) (pte_val(a) == pte_val(b))
/*
* 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_RO) == 0;
}
static inline int pte_dirty(pte_t pte)
{
/* A pte is neither clean nor dirty on s/390. The dirty bit
* is in the storage key. See page_test_and_clear_dirty for
* details.
*/
return 0;
}
static inline int pte_young(pte_t pte)
{
/* A pte is neither young nor old on s/390. The young bit
* is in the storage key. See page_test_and_clear_young for
* details.
*/
return 0;
}
/*
* pgd/pmd/pte modification functions
*/
#ifndef __s390x__
#define pgd_clear(pgd) do { } while (0)
#define pud_clear(pud) do { } while (0)
static inline void pmd_clear_kernel(pmd_t * pmdp)
{
pmd_val(pmdp[0]) = _SEGMENT_ENTRY_EMPTY;
pmd_val(pmdp[1]) = _SEGMENT_ENTRY_EMPTY;
pmd_val(pmdp[2]) = _SEGMENT_ENTRY_EMPTY;
pmd_val(pmdp[3]) = _SEGMENT_ENTRY_EMPTY;
}
#else /* __s390x__ */
#define pgd_clear(pgd) do { } while (0)
static inline void pud_clear_kernel(pud_t *pud)
{
pud_val(*pud) = _REGION3_ENTRY_EMPTY;
}
static inline void pud_clear(pud_t * pud)
{
pud_t *shadow = get_shadow_table(pud);
pud_clear_kernel(pud);
if (shadow)
pud_clear_kernel(shadow);
}
static inline void pmd_clear_kernel(pmd_t * pmdp)
{
pmd_val(*pmdp) = _SEGMENT_ENTRY_EMPTY;
pmd_val1(*pmdp) = _SEGMENT_ENTRY_EMPTY;
}
#endif /* __s390x__ */
static inline void pmd_clear(pmd_t * pmdp)
{
pmd_t *shadow_pmd = get_shadow_table(pmdp);
pmd_clear_kernel(pmdp);
if (shadow_pmd)
pmd_clear_kernel(shadow_pmd);
}
static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
pte_t *shadow_pte = get_shadow_pte(ptep);
pte_val(*ptep) = _PAGE_TYPE_EMPTY;
if (shadow_pte)
pte_val(*shadow_pte) = _PAGE_TYPE_EMPTY;
}
/*
* 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_MASK;
pte_val(pte) |= pgprot_val(newprot);
return pte;
}
static inline pte_t pte_wrprotect(pte_t pte)
{
/* Do not clobber _PAGE_TYPE_NONE pages! */
if (!(pte_val(pte) & _PAGE_INVALID))
pte_val(pte) |= _PAGE_RO;
return pte;
}
static inline pte_t pte_mkwrite(pte_t pte)
{
pte_val(pte) &= ~_PAGE_RO;
return pte;
}
static inline pte_t pte_mkclean(pte_t pte)
{
/* The only user of pte_mkclean is the fork() code.
We must *not* clear the *physical* page dirty bit
just because fork() wants to clear the dirty bit in
*one* of the page's mappings. So we just do nothing. */
return pte;
}
static inline pte_t pte_mkdirty(pte_t pte)
{
/* We do not explicitly set the dirty bit because the
* sske instruction is slow. It is faster to let the
* next instruction set the dirty bit.
*/
return pte;
}
static inline pte_t pte_mkold(pte_t pte)
{
/* S/390 doesn't keep its dirty/referenced bit in the pte.
* There is no point in clearing the real referenced bit.
*/
return pte;
}
static inline pte_t pte_mkyoung(pte_t pte)
{
/* S/390 doesn't keep its dirty/referenced bit in the pte.
* There is no point in setting the real referenced bit.
*/
return pte;
}
#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)
{
return 0;
}
#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)
{
/* No need to flush TLB; bits are in storage key */
return 0;
}
static inline void __ptep_ipte(unsigned long address, pte_t *ptep)
{
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
#ifndef __s390x__
/* S390 has 1mb segments, we are emulating 4MB segments */
pte_t *pto = (pte_t *) (((unsigned long) ptep) & 0x7ffffc00);
#else
/* ipte in zarch mode can do the math */
pte_t *pto = ptep;
#endif
asm volatile(
" ipte %2,%3"
: "=m" (*ptep) : "m" (*ptep),
"a" (pto), "a" (address));
}
pte_val(*ptep) = _PAGE_TYPE_EMPTY;
}
static inline void ptep_invalidate(unsigned long address, pte_t *ptep)
{
__ptep_ipte(address, ptep);
ptep = get_shadow_pte(ptep);
if (ptep)
__ptep_ipte(address, ptep);
}
/*
* 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.
*/
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
#define ptep_get_and_clear(__mm, __address, __ptep) \
({ \
pte_t __pte = *(__ptep); \
if (atomic_read(&(__mm)->mm_users) > 1 || \
(__mm) != current->active_mm) \
ptep_invalidate(__address, __ptep); \
else \
pte_clear((__mm), (__address), (__ptep)); \
__pte; \
})
#define __HAVE_ARCH_PTEP_CLEAR_FLUSH
static inline pte_t ptep_clear_flush(struct vm_area_struct *vma,
unsigned long address, pte_t *ptep)
{
pte_t pte = *ptep;
ptep_invalidate(address, ptep);
return pte;
}
/*
* 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)
{
pte_t pte = *ptep;
if (full)
pte_clear(mm, addr, ptep);
else
ptep_invalidate(addr, ptep);
return pte;
}
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
#define ptep_set_wrprotect(__mm, __addr, __ptep) \
({ \
pte_t __pte = *(__ptep); \
if (pte_write(__pte)) { \
if (atomic_read(&(__mm)->mm_users) > 1 || \
(__mm) != current->active_mm) \
ptep_invalidate(__addr, __ptep); \
set_pte_at(__mm, __addr, __ptep, pte_wrprotect(__pte)); \
} \
})
#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
#define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __dirty) \
({ \
int __changed = !pte_same(*(__ptep), __entry); \
if (__changed) { \
ptep_invalidate(__addr, __ptep); \
set_pte_at((__vma)->vm_mm, __addr, __ptep, __entry); \
} \
__changed; \
})
/*
* Test and clear dirty bit in storage key.
* We can't clear the changed bit atomically. This is a potential
* race against modification of the referenced bit. This function
* should therefore only be called if it is not mapped in any
* address space.
*/
#define __HAVE_ARCH_PAGE_TEST_DIRTY
static inline int page_test_dirty(struct page *page)
{
return (page_get_storage_key(page_to_phys(page)) & _PAGE_CHANGED) != 0;
}
#define __HAVE_ARCH_PAGE_CLEAR_DIRTY
static inline void page_clear_dirty(struct page *page)
{
page_set_storage_key(page_to_phys(page), PAGE_DEFAULT_KEY);
}
/*
* Test and clear referenced bit in storage key.
*/
#define __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
static inline int page_test_and_clear_young(struct page *page)
{
unsigned long physpage = page_to_phys(page);
int ccode;
asm volatile(
" rrbe 0,%1\n"
" ipm %0\n"
" srl %0,28\n"
: "=d" (ccode) : "a" (physpage) : "cc" );
return ccode & 2;
}
/*
* 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;
}
static inline pte_t mk_pte(struct page *page, pgprot_t pgprot)
{
unsigned long physpage = page_to_phys(page);
return mk_pte_phys(physpage, pgprot);
}
#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-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)
#ifndef __s390x__
#define pmd_deref(pmd) (pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN)
#define pud_deref(pmd) ({ BUG(); 0UL; })
#define pgd_deref(pmd) ({ BUG(); 0UL; })
#define pud_offset(pgd, address) ((pud_t *) pgd)
#define pmd_offset(pud, address) ((pmd_t *) pud + pmd_index(address))
#else /* __s390x__ */
#define pmd_deref(pmd) (pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN)
#define pud_deref(pud) (pud_val(pud) & _REGION_ENTRY_ORIGIN)
#define pgd_deref(pgd) ({ BUG(); 0UL; })
#define pud_offset(pgd, address) ((pud_t *) pgd)
static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
pmd_t *pmd = (pmd_t *) pud_deref(*pud);
return pmd + pmd_index(address);
}
#endif /* __s390x__ */
#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_val(pmd) >> PAGE_SHIFT)
/* 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_offset_map_nested(pmd, address) pte_offset_kernel(pmd, address)
#define pte_unmap(pte) do { } while (0)
#define pte_unmap_nested(pte) do { } while (0)
/*
* 31 bit swap entry format:
* A page-table entry has some bits we have to treat in a special way.
* Bits 0, 20 and bit 23 have to be zero, otherwise an specification
* exception will occur instead of a page translation exception. The
* specifiation exception has the bad habit not to store necessary
* information in the lowcore.
* Bit 21 and bit 22 are the page invalid bit and the page protection
* bit. We set both to indicate a swapped page.
* Bit 30 and 31 are used to distinguish the different page types. For
* a swapped page these bits need to be zero.
* This leaves the bits 1-19 and bits 24-29 to store type and offset.
* We use the 5 bits from 25-29 for the type and the 20 bits from 1-19
* plus 24 for the offset.
* 0| offset |0110|o|type |00|
* 0 0000000001111111111 2222 2 22222 33
* 0 1234567890123456789 0123 4 56789 01
*
* 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 an specification
* exception will occur instead of a page translation exception. The
* specifiation exception has the bad habit not to store necessary
* information in the lowcore.
* Bit 53 and bit 54 are the page invalid bit and the page protection
* bit. We set both to indicate a swapped page.
* Bit 62 and 63 are used to distinguish the different page types. For
* a swapped page these bits need to be zero.
* This leaves the bits 0-51 and bits 56-61 to store type and offset.
* We use the 5 bits from 57-61 for the type and the 53 bits from 0-51
* plus 56 for the offset.
* | offset |0110|o|type |00|
* 0000000000111111111122222222223333333333444444444455 5555 5 55566 66
* 0123456789012345678901234567890123456789012345678901 2345 6 78901 23
*/
#ifndef __s390x__
#define __SWP_OFFSET_MASK (~0UL >> 12)
#else
#define __SWP_OFFSET_MASK (~0UL >> 11)
#endif
static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
{
pte_t pte;
offset &= __SWP_OFFSET_MASK;
pte_val(pte) = _PAGE_TYPE_SWAP | ((type & 0x1f) << 2) |
((offset & 1UL) << 7) | ((offset & ~1UL) << 11);
return pte;
}
#define __swp_type(entry) (((entry).val >> 2) & 0x1f)
#define __swp_offset(entry) (((entry).val >> 11) | (((entry).val >> 7) & 1))
#define __swp_entry(type,offset) ((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 })
#ifndef __s390x__
# define PTE_FILE_MAX_BITS 26
#else /* __s390x__ */
# define PTE_FILE_MAX_BITS 59
#endif /* __s390x__ */
#define pte_to_pgoff(__pte) \
((((__pte).pte >> 12) << 7) + (((__pte).pte >> 1) & 0x7f))
#define pgoff_to_pte(__off) \
((pte_t) { ((((__off) & 0x7f) << 1) + (((__off) >> 7) << 12)) \
| _PAGE_TYPE_FILE })
#endif /* !__ASSEMBLY__ */
#define kern_addr_valid(addr) (1)
extern int add_shared_memory(unsigned long start, unsigned long size);
extern int remove_shared_memory(unsigned long start, unsigned long size);
/*
* No page table caches to initialise
*/
#define pgtable_cache_init() do { } while (0)
#define __HAVE_ARCH_MEMMAP_INIT
extern void memmap_init(unsigned long, int, unsigned long, unsigned long);
#include <asm-generic/pgtable.h>
#endif /* _S390_PAGE_H */
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