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android_kernel_xiaomi_sm8350/include/asm-s390/pgtable.h
Martin Schwidefsky ba8a9229ab [S390] tlb flush fix. 
The current tlb flushing code for page table entries violates the
s390 architecture in a small detail. The relevant section from the
principles of operation (SA22-7832-02 page 3-47):

   "A valid table entry must not be changed while it is attached
   to any CPU and may be used for translation by that CPU except to
   (1) invalidate the entry by using INVALIDATE PAGE TABLE ENTRY or
   INVALIDATE DAT TABLE ENTRY, (2) alter bits 56-63 of a page-table
   entry, or (3) make a change by means of a COMPARE AND SWAP AND
   PURGE instruction that purges the TLB."

That means if one thread of a multithreaded applciation uses a vma
while another thread does an unmap on it, the page table entries of
that vma needs to get removed with IPTE, IDTE or CSP. In some strange
and rare situations a cpu could check-stop (die) because a entry has
been pushed out of the TLB that is still needed to complete a
(milli-coded) instruction. I've never seen it happen with the current
code on any of the supported machines, so right now this is a
theoretical problem. But I want to fix it nevertheless, to avoid
headaches in the futures.

To get this implemented correctly without changing common code the
primitives ptep_get_and_clear, ptep_get_and_clear_full and
ptep_set_wrprotect need to use the IPTE instruction to invalidate the
pte before the new pte value gets stored. If IPTE is always used for
the three primitives three important operations will have a performace
hit: fork, mprotect and exit_mmap. Time for some workarounds:

* 1: ptep_get_and_clear_full is used in unmap_vmas to remove page
tables entries in a batched tlb gather operation. If the mmu_gather
context passed to unmap_vmas has been started with full_mm_flush==1
or if only one cpu is online or if the only user of a mm_struct is the
current process then the fullmm indication in the mmu_gather context is
set to one. All TLBs for mm_struct are flushed by the tlb_gather_mmu
call. No new TLBs can be created while the unmap is in progress. In
this case ptep_get_and_clear_full clears the ptes with a simple store.

* 2: ptep_get_and_clear is used in change_protection to clear the
ptes from the page tables before they are reentered with the new
access flags. At the end of the update flush_tlb_range clears the
remaining TLBs. In general the ptep_get_and_clear has to issue IPTE
for each pte and flush_tlb_range is a nop. But if there is only one
user of the mm_struct then ptep_get_and_clear uses simple stores
to do the update and flush_tlb_range will flush the TLBs.

* 3: Similar to 2, ptep_set_wrprotect is used in copy_page_range
for a fork to make all ptes of a cow mapping read-only. At the end of
of copy_page_range dup_mmap will flush the TLBs with a call to
flush_tlb_mm.  Check for mm->mm_users and if there is only one user
avoid using IPTE in ptep_set_wrprotect and let flush_tlb_mm clear the
TLBs.

Overall for single threaded programs the tlb flush code now performs
better, for multi threaded programs it is slightly worse. In particular
exit_mmap() now does a single IDTE for the mm and then just frees every
page cache reference and every page table page directly without a delay
over the mmu_gather structure.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-10-22 12:52:48 +02:00

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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
#include <asm-generic/4level-fixup.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>
struct vm_area_struct; /* forward declaration (include/linux/mm.h) */
struct mm_struct;
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 PGDIR_SHIFT 22
#else /* __s390x__ */
# define PMD_SHIFT 21
# define PGDIR_SHIFT 31
#endif /* __s390x__ */
#define PMD_SIZE (1UL << PMD_SHIFT)
#define PMD_MASK (~(PMD_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_PGD 512
#else /* __s390x__ */
# define PTRS_PER_PTE 512
# define PTRS_PER_PMD 1024
# 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 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 lenght
*
* 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 */
#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 entry */
#define _PAGE_TABLE_LEN 0xf /* only full page-tables */
#define _PAGE_TABLE_COM 0x10 /* common page-table */
#define _PAGE_TABLE_INV 0x20 /* invalid page-table */
#define _SEG_PRESENT 0x001 /* Software (overlap with PTL) */
/* Bits int the storage key */
#define _PAGE_CHANGED 0x02 /* HW changed bit */
#define _PAGE_REFERENCED 0x04 /* HW referenced bit */
#define _USER_SEG_TABLE_LEN 0x7f /* user-segment-table up to 2 GB */
#define _KERNEL_SEG_TABLE_LEN 0x7f /* kernel-segment-table up to 2 GB */
/*
* User and Kernel pagetables are identical
*/
#define _PAGE_TABLE _PAGE_TABLE_LEN
#define _KERNPG_TABLE _PAGE_TABLE_LEN
/*
* The Kernel segment-tables includes the User segment-table
*/
#define _SEGMENT_TABLE (_USER_SEG_TABLE_LEN|0x80000000|0x100)
#define _KERNSEG_TABLE _KERNEL_SEG_TABLE_LEN
#define USER_STD_MASK 0x00000080UL
#else /* __s390x__ */
/* Bits in the segment table entry */
#define _PMD_ENTRY_INV 0x20 /* invalid segment table entry */
#define _PMD_ENTRY 0x00
/* Bits in the region third table entry */
#define _PGD_ENTRY_INV 0x20 /* invalid region table entry */
#define _PGD_ENTRY 0x07
/*
* User and kernel page directory
*/
#define _REGION_THIRD 0x4
#define _REGION_THIRD_LEN 0x3
#define _REGION_TABLE (_REGION_THIRD|_REGION_THIRD_LEN|0x40|0x100)
#define _KERN_REGION_TABLE (_REGION_THIRD|_REGION_THIRD_LEN)
#define USER_STD_MASK 0x0000000000000080UL
/* Bits in the storage key */
#define _PAGE_CHANGED 0x02 /* HW changed bit */
#define _PAGE_REFERENCED 0x04 /* HW referenced bit */
#endif /* __s390x__ */
/*
* 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 PMD_SHADOW_SHIFT 1
# define PGD_SHADOW_SHIFT 1
#else /* __s390x__ */
# define PMD_SHADOW_SHIFT 2
# define PGD_SHADOW_SHIFT 2
#endif /* __s390x__ */
static inline struct page *get_shadow_page(struct page *page)
{
if (s390_noexec && !list_empty(&page->lru))
return virt_to_page(page->lru.next);
return NULL;
}
static inline pte_t *get_shadow_pte(pte_t *ptep)
{
unsigned long pteptr = (unsigned long) (ptep);
if (s390_noexec) {
unsigned long offset = pteptr & (PAGE_SIZE - 1);
void *addr = (void *) (pteptr ^ offset);
struct page *page = virt_to_page(addr);
if (!list_empty(&page->lru))
return (pte_t *) ((unsigned long) page->lru.next |
offset);
}
return NULL;
}
static inline pmd_t *get_shadow_pmd(pmd_t *pmdp)
{
unsigned long pmdptr = (unsigned long) (pmdp);
if (s390_noexec) {
unsigned long offset = pmdptr &
((PAGE_SIZE << PMD_SHADOW_SHIFT) - 1);
void *addr = (void *) (pmdptr ^ offset);
struct page *page = virt_to_page(addr);
if (!list_empty(&page->lru))
return (pmd_t *) ((unsigned long) page->lru.next |
offset);
}
return NULL;
}
static inline pgd_t *get_shadow_pgd(pgd_t *pgdp)
{
unsigned long pgdptr = (unsigned long) (pgdp);
if (s390_noexec) {
unsigned long offset = pgdptr &
((PAGE_SIZE << PGD_SHADOW_SHIFT) - 1);
void *addr = (void *) (pgdptr ^ offset);
struct page *page = virt_to_page(addr);
if (!list_empty(&page->lru))
return (pgd_t *) ((unsigned long) page->lru.next |
offset);
}
return NULL;
}
/*
* 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 pmd_present(pmd_t pmd) { return pmd_val(pmd) & _SEG_PRESENT; }
static inline int pmd_none(pmd_t pmd) { return pmd_val(pmd) & _PAGE_TABLE_INV; }
static inline int pmd_bad(pmd_t pmd)
{
return (pmd_val(pmd) & (~PAGE_MASK & ~_PAGE_TABLE_INV)) != _PAGE_TABLE;
}
#else /* __s390x__ */
static inline int pgd_present(pgd_t pgd)
{
return (pgd_val(pgd) & ~PAGE_MASK) == _PGD_ENTRY;
}
static inline int pgd_none(pgd_t pgd)
{
return pgd_val(pgd) & _PGD_ENTRY_INV;
}
static inline int pgd_bad(pgd_t pgd)
{
return (pgd_val(pgd) & (~PAGE_MASK & ~_PGD_ENTRY_INV)) != _PGD_ENTRY;
}
static inline int pmd_present(pmd_t pmd)
{
return (pmd_val(pmd) & ~PAGE_MASK) == _PMD_ENTRY;
}
static inline int pmd_none(pmd_t pmd)
{
return pmd_val(pmd) & _PMD_ENTRY_INV;
}
static inline int pmd_bad(pmd_t pmd)
{
return (pmd_val(pmd) & (~PAGE_MASK & ~_PMD_ENTRY_INV)) != _PMD_ENTRY;
}
#endif /* __s390x__ */
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__
static inline void pgd_clear(pgd_t * pgdp) { }
static inline void pmd_clear_kernel(pmd_t * pmdp)
{
pmd_val(pmdp[0]) = _PAGE_TABLE_INV;
pmd_val(pmdp[1]) = _PAGE_TABLE_INV;
pmd_val(pmdp[2]) = _PAGE_TABLE_INV;
pmd_val(pmdp[3]) = _PAGE_TABLE_INV;
}
static inline void pmd_clear(pmd_t * pmdp)
{
pmd_t *shadow_pmd = get_shadow_pmd(pmdp);
pmd_clear_kernel(pmdp);
if (shadow_pmd)
pmd_clear_kernel(shadow_pmd);
}
#else /* __s390x__ */
static inline void pgd_clear_kernel(pgd_t * pgdp)
{
pgd_val(*pgdp) = _PGD_ENTRY_INV | _PGD_ENTRY;
}
static inline void pgd_clear(pgd_t * pgdp)
{
pgd_t *shadow_pgd = get_shadow_pgd(pgdp);
pgd_clear_kernel(pgdp);
if (shadow_pgd)
pgd_clear_kernel(shadow_pgd);
}
static inline void pmd_clear_kernel(pmd_t * pmdp)
{
pmd_val(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY;
pmd_val1(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY;
}
static inline void pmd_clear(pmd_t * pmdp)
{
pmd_t *shadow_pmd = get_shadow_pmd(pmdp);
pmd_clear_kernel(pmdp);
if (shadow_pmd)
pmd_clear_kernel(shadow_pmd);
}
#endif /* __s390x__ */
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);
}
static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
{
unsigned long physpage = __pa((pfn) << PAGE_SHIFT);
return mk_pte_phys(physpage, pgprot);
}
#ifdef __s390x__
static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
{
unsigned long physpage = __pa((pfn) << PAGE_SHIFT);
return __pmd(physpage + pgprot_val(pgprot));
}
#endif /* __s390x__ */
#define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT)
#define pte_page(x) pfn_to_page(pte_pfn(x))
#define pmd_page_vaddr(pmd) (pmd_val(pmd) & PAGE_MASK)
#define pmd_page(pmd) pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT)
#define pgd_page_vaddr(pgd) (pgd_val(pgd) & PAGE_MASK)
#define pgd_page(pgd) pfn_to_page(pgd_val(pgd) >> PAGE_SHIFT)
/* to find an entry in a page-table-directory */
#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
/* to find an entry in a kernel page-table-directory */
#define pgd_offset_k(address) pgd_offset(&init_mm, address)
#ifndef __s390x__
/* Find an entry in the second-level page table.. */
static inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
{
return (pmd_t *) dir;
}
#else /* __s390x__ */
/* Find an entry in the second-level page table.. */
#define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
#define pmd_offset(dir,addr) \
((pmd_t *) pgd_page_vaddr(*(dir)) + pmd_index(addr))
#endif /* __s390x__ */
/* Find an entry in the third-level page table.. */
#define pte_index(address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE-1))
#define pte_offset_kernel(pmd, address) \
((pte_t *) pmd_page_vaddr(*(pmd)) + pte_index(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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