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remarkable-linux/include/asm-ia64/page.h
Martin Schwidefsky 2f569afd9c CONFIG_HIGHPTE vs. sub-page page tables. 
Background: I've implemented 1K/2K page tables for s390.  These sub-page
page tables are required to properly support the s390 virtualization
instruction with KVM.  The SIE instruction requires that the page tables
have 256 page table entries (pte) followed by 256 page status table entries
(pgste).  The pgstes are only required if the process is using the SIE
instruction.  The pgstes are updated by the hardware and by the hypervisor
for a number of reasons, one of them is dirty and reference bit tracking.
To avoid wasting memory the standard pte table allocation should return
1K/2K (31/64 bit) and 2K/4K if the process is using SIE.

Problem: Page size on s390 is 4K, page table size is 1K or 2K.  That means
the s390 version for pte_alloc_one cannot return a pointer to a struct
page.  Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one
cannot return a pointer to a pte either, since that would require more than
32 bit for the return value of pte_alloc_one (and the pte * would not be
accessible since its not kmapped).

Solution: The only solution I found to this dilemma is a new typedef: a
pgtable_t.  For s390 pgtable_t will be a (pte *) - to be introduced with a
later patch.  For everybody else it will be a (struct page *).  The
additional problem with the initialization of the ptl lock and the
NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and
a destructor pgtable_page_dtor.  The page table allocation and free
functions need to call these two whenever a page table page is allocated or
freed.  pmd_populate will get a pgtable_t instead of a struct page pointer.
 To get the pgtable_t back from a pmd entry that has been installed with
pmd_populate a new function pmd_pgtable is added.  It replaces the pmd_page
call in free_pte_range and apply_to_pte_range.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:42 -08:00

231 lines
6.3 KiB
C
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#ifndef _ASM_IA64_PAGE_H
#define _ASM_IA64_PAGE_H
/*
* Pagetable related stuff.
*
* Copyright (C) 1998, 1999, 2002 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*/
#include <asm/intrinsics.h>
#include <asm/types.h>
/*
* The top three bits of an IA64 address are its Region Number.
* Different regions are assigned to different purposes.
*/
#define RGN_SHIFT (61)
#define RGN_BASE(r) (__IA64_UL_CONST(r)<<RGN_SHIFT)
#define RGN_BITS (RGN_BASE(-1))
#define RGN_KERNEL 7 /* Identity mapped region */
#define RGN_UNCACHED 6 /* Identity mapped I/O region */
#define RGN_GATE 5 /* Gate page, Kernel text, etc */
#define RGN_HPAGE 4 /* For Huge TLB pages */
/*
* PAGE_SHIFT determines the actual kernel page size.
*/
#if defined(CONFIG_IA64_PAGE_SIZE_4KB)
# define PAGE_SHIFT 12
#elif defined(CONFIG_IA64_PAGE_SIZE_8KB)
# define PAGE_SHIFT 13
#elif defined(CONFIG_IA64_PAGE_SIZE_16KB)
# define PAGE_SHIFT 14
#elif defined(CONFIG_IA64_PAGE_SIZE_64KB)
# define PAGE_SHIFT 16
#else
# error Unsupported page size!
#endif
#define PAGE_SIZE (__IA64_UL_CONST(1) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE - 1))
#define PAGE_ALIGN(addr) (((addr) + PAGE_SIZE - 1) & PAGE_MASK)
#define PERCPU_PAGE_SHIFT 16 /* log2() of max. size of per-CPU area */
#define PERCPU_PAGE_SIZE (__IA64_UL_CONST(1) << PERCPU_PAGE_SHIFT)
#ifdef CONFIG_HUGETLB_PAGE
# define HPAGE_REGION_BASE RGN_BASE(RGN_HPAGE)
# define HPAGE_SHIFT hpage_shift
# define HPAGE_SHIFT_DEFAULT 28 /* check ia64 SDM for architecture supported size */
# define HPAGE_SIZE (__IA64_UL_CONST(1) << HPAGE_SHIFT)
# define HPAGE_MASK (~(HPAGE_SIZE - 1))
# define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
# define ARCH_HAS_HUGEPAGE_ONLY_RANGE
# define ARCH_HAS_PREPARE_HUGEPAGE_RANGE
# define ARCH_HAS_HUGETLB_FREE_PGD_RANGE
#endif /* CONFIG_HUGETLB_PAGE */
#ifdef __ASSEMBLY__
# define __pa(x) ((x) - PAGE_OFFSET)
# define __va(x) ((x) + PAGE_OFFSET)
#else /* !__ASSEMBLY */
# define STRICT_MM_TYPECHECKS
extern void clear_page (void *page);
extern void copy_page (void *to, void *from);
/*
* clear_user_page() and copy_user_page() can't be inline functions because
* flush_dcache_page() can't be defined until later...
*/
#define clear_user_page(addr, vaddr, page) \
do { \
clear_page(addr); \
flush_dcache_page(page); \
} while (0)
#define copy_user_page(to, from, vaddr, page) \
do { \
copy_page((to), (from)); \
flush_dcache_page(page); \
} while (0)
#define __alloc_zeroed_user_highpage(movableflags, vma, vaddr) \
({ \
struct page *page = alloc_page_vma( \
GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vaddr); \
if (page) \
flush_dcache_page(page); \
page; \
})
#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
#ifdef CONFIG_VIRTUAL_MEM_MAP
extern int ia64_pfn_valid (unsigned long pfn);
#else
# define ia64_pfn_valid(pfn) 1
#endif
#ifdef CONFIG_VIRTUAL_MEM_MAP
extern struct page *vmem_map;
#ifdef CONFIG_DISCONTIGMEM
# define page_to_pfn(page) ((unsigned long) (page - vmem_map))
# define pfn_to_page(pfn) (vmem_map + (pfn))
#else
# include <asm-generic/memory_model.h>
#endif
#else
# include <asm-generic/memory_model.h>
#endif
#ifdef CONFIG_FLATMEM
# define pfn_valid(pfn) (((pfn) < max_mapnr) && ia64_pfn_valid(pfn))
#elif defined(CONFIG_DISCONTIGMEM)
extern unsigned long min_low_pfn;
extern unsigned long max_low_pfn;
# define pfn_valid(pfn) (((pfn) >= min_low_pfn) && ((pfn) < max_low_pfn) && ia64_pfn_valid(pfn))
#endif
#define page_to_phys(page) (page_to_pfn(page) << PAGE_SHIFT)
#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
typedef union ia64_va {
struct {
unsigned long off : 61; /* intra-region offset */
unsigned long reg : 3; /* region number */
} f;
unsigned long l;
void *p;
} ia64_va;
/*
* Note: These macros depend on the fact that PAGE_OFFSET has all
* region bits set to 1 and all other bits set to zero. They are
* expressed in this way to ensure they result in a single "dep"
* instruction.
*/
#define __pa(x) ({ia64_va _v; _v.l = (long) (x); _v.f.reg = 0; _v.l;})
#define __va(x) ({ia64_va _v; _v.l = (long) (x); _v.f.reg = -1; _v.p;})
#define REGION_NUMBER(x) ({ia64_va _v; _v.l = (long) (x); _v.f.reg;})
#define REGION_OFFSET(x) ({ia64_va _v; _v.l = (long) (x); _v.f.off;})
#ifdef CONFIG_HUGETLB_PAGE
# define htlbpage_to_page(x) (((unsigned long) REGION_NUMBER(x) << 61) \
| (REGION_OFFSET(x) >> (HPAGE_SHIFT-PAGE_SHIFT)))
# define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
# define is_hugepage_only_range(mm, addr, len) \
(REGION_NUMBER(addr) == RGN_HPAGE || \
REGION_NUMBER((addr)+(len)-1) == RGN_HPAGE)
extern unsigned int hpage_shift;
#endif
static __inline__ int
get_order (unsigned long size)
{
long double d = size - 1;
long order;
order = ia64_getf_exp(d);
order = order - PAGE_SHIFT - 0xffff + 1;
if (order < 0)
order = 0;
return order;
}
#endif /* !__ASSEMBLY__ */
#ifdef STRICT_MM_TYPECHECKS
/*
* These are used to make use of C type-checking..
*/
typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long pmd; } pmd_t;
#ifdef CONFIG_PGTABLE_4
typedef struct { unsigned long pud; } pud_t;
#endif
typedef struct { unsigned long pgd; } pgd_t;
typedef struct { unsigned long pgprot; } pgprot_t;
typedef struct page *pgtable_t;
# define pte_val(x) ((x).pte)
# define pmd_val(x) ((x).pmd)
#ifdef CONFIG_PGTABLE_4
# define pud_val(x) ((x).pud)
#endif
# define pgd_val(x) ((x).pgd)
# define pgprot_val(x) ((x).pgprot)
# define __pte(x) ((pte_t) { (x) } )
# define __pgprot(x) ((pgprot_t) { (x) } )
#else /* !STRICT_MM_TYPECHECKS */
/*
* .. while these make it easier on the compiler
*/
# ifndef __ASSEMBLY__
typedef unsigned long pte_t;
typedef unsigned long pmd_t;
typedef unsigned long pgd_t;
typedef unsigned long pgprot_t;
typedef struct page *pgtable_t;
# endif
# define pte_val(x) (x)
# define pmd_val(x) (x)
# define pgd_val(x) (x)
# define pgprot_val(x) (x)
# define __pte(x) (x)
# define __pgd(x) (x)
# define __pgprot(x) (x)
#endif /* !STRICT_MM_TYPECHECKS */
#define PAGE_OFFSET RGN_BASE(RGN_KERNEL)
#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC | \
(((current->personality & READ_IMPLIES_EXEC) != 0) \
? VM_EXEC : 0))
#endif /* _ASM_IA64_PAGE_H */
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