2f569afd9c
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>
147 lines
4.1 KiB
C
147 lines
4.1 KiB
C
/* $Id: page.h,v 1.39 2002/02/09 19:49:31 davem Exp $ */
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#ifndef _SPARC64_PAGE_H
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#define _SPARC64_PAGE_H
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#include <linux/const.h>
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#if defined(CONFIG_SPARC64_PAGE_SIZE_8KB)
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#define PAGE_SHIFT 13
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#elif defined(CONFIG_SPARC64_PAGE_SIZE_64KB)
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#define PAGE_SHIFT 16
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#elif defined(CONFIG_SPARC64_PAGE_SIZE_512KB)
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#define PAGE_SHIFT 19
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#elif defined(CONFIG_SPARC64_PAGE_SIZE_4MB)
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#define PAGE_SHIFT 22
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#else
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#error No page size specified in kernel configuration
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#endif
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#define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT)
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#define PAGE_MASK (~(PAGE_SIZE-1))
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/* Flushing for D-cache alias handling is only needed if
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* the page size is smaller than 16K.
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*/
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#if PAGE_SHIFT < 14
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#define DCACHE_ALIASING_POSSIBLE
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#endif
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#if defined(CONFIG_HUGETLB_PAGE_SIZE_4MB)
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#define HPAGE_SHIFT 22
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#elif defined(CONFIG_HUGETLB_PAGE_SIZE_512K)
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#define HPAGE_SHIFT 19
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#elif defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
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#define HPAGE_SHIFT 16
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#endif
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#ifdef CONFIG_HUGETLB_PAGE
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#define HPAGE_SIZE (_AC(1,UL) << HPAGE_SHIFT)
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#define HPAGE_MASK (~(HPAGE_SIZE - 1UL))
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#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
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#define ARCH_HAS_SETCLEAR_HUGE_PTE
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#define ARCH_HAS_HUGETLB_PREFAULT_HOOK
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#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
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#endif
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#ifndef __ASSEMBLY__
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extern void _clear_page(void *page);
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#define clear_page(X) _clear_page((void *)(X))
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struct page;
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extern void clear_user_page(void *addr, unsigned long vaddr, struct page *page);
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#define copy_page(X,Y) memcpy((void *)(X), (void *)(Y), PAGE_SIZE)
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extern void copy_user_page(void *to, void *from, unsigned long vaddr, struct page *topage);
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/* Unlike sparc32, sparc64's parameter passing API is more
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* sane in that structures which as small enough are passed
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* in registers instead of on the stack. Thus, setting
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* STRICT_MM_TYPECHECKS does not generate worse code so
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* let's enable it to get the type checking.
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*/
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#define STRICT_MM_TYPECHECKS
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#ifdef STRICT_MM_TYPECHECKS
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/* These are used to make use of C type-checking.. */
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typedef struct { unsigned long pte; } pte_t;
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typedef struct { unsigned long iopte; } iopte_t;
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typedef struct { unsigned int pmd; } pmd_t;
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typedef struct { unsigned int pgd; } pgd_t;
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typedef struct { unsigned long pgprot; } pgprot_t;
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#define pte_val(x) ((x).pte)
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#define iopte_val(x) ((x).iopte)
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#define pmd_val(x) ((x).pmd)
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#define pgd_val(x) ((x).pgd)
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#define pgprot_val(x) ((x).pgprot)
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#define __pte(x) ((pte_t) { (x) } )
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#define __iopte(x) ((iopte_t) { (x) } )
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#define __pmd(x) ((pmd_t) { (x) } )
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#define __pgd(x) ((pgd_t) { (x) } )
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#define __pgprot(x) ((pgprot_t) { (x) } )
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#else
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/* .. while these make it easier on the compiler */
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typedef unsigned long pte_t;
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typedef unsigned long iopte_t;
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typedef unsigned int pmd_t;
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typedef unsigned int pgd_t;
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typedef unsigned long pgprot_t;
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#define pte_val(x) (x)
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#define iopte_val(x) (x)
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#define pmd_val(x) (x)
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#define pgd_val(x) (x)
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#define pgprot_val(x) (x)
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#define __pte(x) (x)
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#define __iopte(x) (x)
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#define __pmd(x) (x)
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#define __pgd(x) (x)
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#define __pgprot(x) (x)
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#endif /* (STRICT_MM_TYPECHECKS) */
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typedef struct page *pgtable_t;
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#define TASK_UNMAPPED_BASE (test_thread_flag(TIF_32BIT) ? \
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(_AC(0x0000000070000000,UL)) : \
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(_AC(0xfffff80000000000,UL) + (1UL << 32UL)))
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#include <asm-generic/memory_model.h>
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#endif /* !(__ASSEMBLY__) */
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/* to align the pointer to the (next) page boundary */
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#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK)
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/* We used to stick this into a hard-coded global register (%g4)
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* but that does not make sense anymore.
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*/
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#define PAGE_OFFSET _AC(0xFFFFF80000000000,UL)
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#ifndef __ASSEMBLY__
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#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
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#define __va(x) ((void *)((unsigned long) (x) + PAGE_OFFSET))
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#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
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#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr)>>PAGE_SHIFT)
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#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
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#define virt_to_phys __pa
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#define phys_to_virt __va
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#endif /* !(__ASSEMBLY__) */
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#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#include <asm-generic/page.h>
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#endif /* _SPARC64_PAGE_H */
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