forked from Minki/linux
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>
167 lines
4.5 KiB
C
167 lines
4.5 KiB
C
/* $Id: page.h,v 1.55 2000/10/30 21:01:41 davem Exp $
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* page.h: Various defines and such for MMU operations on the Sparc for
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* the Linux kernel.
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*
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* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
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*/
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#ifndef _SPARC_PAGE_H
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#define _SPARC_PAGE_H
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#ifdef CONFIG_SUN4
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#define PAGE_SHIFT 13
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#else
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#define PAGE_SHIFT 12
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#endif
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#ifndef __ASSEMBLY__
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/* I have my suspicions... -DaveM */
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#define PAGE_SIZE (1UL << PAGE_SHIFT)
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#else
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#define PAGE_SIZE (1 << PAGE_SHIFT)
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#endif
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#define PAGE_MASK (~(PAGE_SIZE-1))
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#include <asm/btfixup.h>
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#ifndef __ASSEMBLY__
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#define clear_page(page) memset((void *)(page), 0, PAGE_SIZE)
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#define copy_page(to,from) memcpy((void *)(to), (void *)(from), PAGE_SIZE)
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#define clear_user_page(addr, vaddr, page) \
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do { clear_page(addr); \
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sparc_flush_page_to_ram(page); \
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} while (0)
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#define copy_user_page(to, from, vaddr, page) \
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do { copy_page(to, from); \
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sparc_flush_page_to_ram(page); \
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} while (0)
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/* The following structure is used to hold the physical
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* memory configuration of the machine. This is filled in
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* probe_memory() and is later used by mem_init() to set up
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* mem_map[]. We statically allocate SPARC_PHYS_BANKS of
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* these structs, this is arbitrary. The entry after the
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* last valid one has num_bytes==0.
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*/
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struct sparc_phys_banks {
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unsigned long base_addr;
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unsigned long num_bytes;
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};
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#define SPARC_PHYS_BANKS 32
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extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS+1];
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/* Cache alias structure. Entry is valid if context != -1. */
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struct cache_palias {
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unsigned long vaddr;
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int context;
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};
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extern struct cache_palias *sparc_aliases;
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/* passing structs on the Sparc slow us down tremendously... */
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/* #define STRICT_MM_TYPECHECKS */
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#ifdef STRICT_MM_TYPECHECKS
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/*
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* These are used to make use of C type-checking..
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*/
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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 long pmdv[16]; } pmd_t;
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typedef struct { unsigned long pgd; } pgd_t;
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typedef struct { unsigned long ctxd; } ctxd_t;
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typedef struct { unsigned long pgprot; } pgprot_t;
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typedef struct { unsigned long iopgprot; } iopgprot_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).pmdv[0])
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#define pgd_val(x) ((x).pgd)
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#define ctxd_val(x) ((x).ctxd)
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#define pgprot_val(x) ((x).pgprot)
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#define iopgprot_val(x) ((x).iopgprot)
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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) } ) */ /* XXX procedure with loop */
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#define __pgd(x) ((pgd_t) { (x) } )
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#define __ctxd(x) ((ctxd_t) { (x) } )
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#define __pgprot(x) ((pgprot_t) { (x) } )
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#define __iopgprot(x) ((iopgprot_t) { (x) } )
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#else
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/*
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* .. while these make it easier on the compiler
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*/
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typedef unsigned long pte_t;
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typedef unsigned long iopte_t;
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typedef struct { unsigned long pmdv[16]; } pmd_t;
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typedef unsigned long pgd_t;
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typedef unsigned long ctxd_t;
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typedef unsigned long pgprot_t;
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typedef unsigned long iopgprot_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).pmdv[0])
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#define pgd_val(x) (x)
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#define ctxd_val(x) (x)
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#define pgprot_val(x) (x)
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#define iopgprot_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) */ /* XXX later */
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#define __pgd(x) (x)
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#define __ctxd(x) (x)
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#define __pgprot(x) (x)
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#define __iopgprot(x) (x)
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#endif
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typedef struct page *pgtable_t;
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extern unsigned long sparc_unmapped_base;
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BTFIXUPDEF_SETHI(sparc_unmapped_base)
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#define TASK_UNMAPPED_BASE BTFIXUP_SETHI(sparc_unmapped_base)
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#else /* !(__ASSEMBLY__) */
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#define __pgprot(x) (x)
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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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#define PAGE_OFFSET 0xf0000000
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#ifndef __ASSEMBLY__
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extern unsigned long phys_base;
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extern unsigned long pfn_base;
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#endif
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#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + phys_base)
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#define __va(x) ((void *)((unsigned long) (x) - phys_base + PAGE_OFFSET))
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#define virt_to_phys __pa
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#define phys_to_virt __va
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#define ARCH_PFN_OFFSET (pfn_base)
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#define virt_to_page(kaddr) (mem_map + ((((unsigned long)(kaddr)-PAGE_OFFSET)>>PAGE_SHIFT)))
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#define pfn_valid(pfn) (((pfn) >= (pfn_base)) && (((pfn)-(pfn_base)) < max_mapnr))
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#define virt_addr_valid(kaddr) ((((unsigned long)(kaddr)-PAGE_OFFSET)>>PAGE_SHIFT) < max_mapnr)
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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/memory_model.h>
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#include <asm-generic/page.h>
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#endif /* _SPARC_PAGE_H */
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