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f4eb07c17d
Virtual memmap support for s390. Inspired by the ia64 implementation. Unlike ia64 we need a mechanism which allows us to dynamically attach shared memory regions. These memory regions are accessed via the dcss device driver. dcss implements the 'direct_access' operation, which requires struct pages for every single shared page. Therefore this implementation provides an interface to attach/detach shared memory: int add_shared_memory(unsigned long start, unsigned long size); int remove_shared_memory(unsigned long start, unsigned long size); The purpose of the add_shared_memory function is to add the given memory range to the 1:1 mapping and to make sure that the corresponding range in the vmemmap is backed with physical pages. It also initialises the new struct pages. remove_shared_memory in turn only invalidates the page table entries in the 1:1 mapping. The page tables and the memory used for struct pages in the vmemmap are currently not freed. They will be reused when the next segment will be attached. Given that the maximum size of a shared memory region is 2GB and in addition all regions must reside below 2GB this is not too much of a restriction, but there is room for improvement. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
165 lines
3.7 KiB
C
165 lines
3.7 KiB
C
/*
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* include/asm-s390/pgalloc.h
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*
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* S390 version
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* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Hartmut Penner (hp@de.ibm.com)
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* Martin Schwidefsky (schwidefsky@de.ibm.com)
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*
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* Derived from "include/asm-i386/pgalloc.h"
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* Copyright (C) 1994 Linus Torvalds
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*/
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#ifndef _S390_PGALLOC_H
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#define _S390_PGALLOC_H
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#include <linux/threads.h>
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#include <linux/gfp.h>
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#include <linux/mm.h>
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#define check_pgt_cache() do {} while (0)
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extern void diag10(unsigned long addr);
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/*
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* Page allocation orders.
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*/
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#ifndef __s390x__
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# define PTE_ALLOC_ORDER 0
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# define PMD_ALLOC_ORDER 0
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# define PGD_ALLOC_ORDER 1
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#else /* __s390x__ */
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# define PTE_ALLOC_ORDER 0
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# define PMD_ALLOC_ORDER 2
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# define PGD_ALLOC_ORDER 2
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#endif /* __s390x__ */
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/*
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* Allocate and free page tables. The xxx_kernel() versions are
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* used to allocate a kernel page table - this turns on ASN bits
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* if any.
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*/
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static inline pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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pgd_t *pgd = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_ALLOC_ORDER);
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int i;
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if (!pgd)
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return NULL;
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for (i = 0; i < PTRS_PER_PGD; i++)
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#ifndef __s390x__
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pmd_clear(pmd_offset(pgd + i, i*PGDIR_SIZE));
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#else
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pgd_clear(pgd + i);
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#endif
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return pgd;
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}
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static inline void pgd_free(pgd_t *pgd)
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{
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free_pages((unsigned long) pgd, PGD_ALLOC_ORDER);
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}
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#ifndef __s390x__
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/*
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* page middle directory allocation/free routines.
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* We use pmd cache only on s390x, so these are dummy routines. This
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* code never triggers because the pgd will always be present.
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*/
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#define pmd_alloc_one(mm,address) ({ BUG(); ((pmd_t *)2); })
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#define pmd_free(x) do { } while (0)
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#define __pmd_free_tlb(tlb,x) do { } while (0)
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#define pgd_populate(mm, pmd, pte) BUG()
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#else /* __s390x__ */
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static inline pmd_t * pmd_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
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{
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pmd_t *pmd = (pmd_t *) __get_free_pages(GFP_KERNEL, PMD_ALLOC_ORDER);
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int i;
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if (!pmd)
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return NULL;
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for (i=0; i < PTRS_PER_PMD; i++)
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pmd_clear(pmd + i);
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return pmd;
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}
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static inline void pmd_free (pmd_t *pmd)
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{
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free_pages((unsigned long) pmd, PMD_ALLOC_ORDER);
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}
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#define __pmd_free_tlb(tlb,pmd) \
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do { \
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tlb_flush_mmu(tlb, 0, 0); \
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pmd_free(pmd); \
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} while (0)
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static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
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{
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pgd_val(*pgd) = _PGD_ENTRY | __pa(pmd);
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}
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#endif /* __s390x__ */
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static inline void
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pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
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{
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#ifndef __s390x__
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pmd_val(pmd[0]) = _PAGE_TABLE + __pa(pte);
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pmd_val(pmd[1]) = _PAGE_TABLE + __pa(pte+256);
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pmd_val(pmd[2]) = _PAGE_TABLE + __pa(pte+512);
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pmd_val(pmd[3]) = _PAGE_TABLE + __pa(pte+768);
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#else /* __s390x__ */
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pmd_val(*pmd) = _PMD_ENTRY + __pa(pte);
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pmd_val1(*pmd) = _PMD_ENTRY + __pa(pte+256);
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#endif /* __s390x__ */
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}
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static inline void
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pmd_populate(struct mm_struct *mm, pmd_t *pmd, struct page *page)
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{
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pmd_populate_kernel(mm, pmd, (pte_t *)page_to_phys(page));
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}
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/*
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* page table entry allocation/free routines.
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*/
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static inline pte_t *
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pte_alloc_one_kernel(struct mm_struct *mm, unsigned long vmaddr)
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{
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pte_t *pte = (pte_t *) __get_free_page(GFP_KERNEL|__GFP_REPEAT);
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int i;
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if (!pte)
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return NULL;
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for (i=0; i < PTRS_PER_PTE; i++) {
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pte_clear(mm, vmaddr, pte + i);
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vmaddr += PAGE_SIZE;
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}
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return pte;
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}
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static inline struct page *
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pte_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
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{
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pte_t *pte = pte_alloc_one_kernel(mm, vmaddr);
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if (pte)
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return virt_to_page(pte);
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return NULL;
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}
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static inline void pte_free_kernel(pte_t *pte)
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{
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free_page((unsigned long) pte);
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}
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static inline void pte_free(struct page *pte)
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{
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__free_page(pte);
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}
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#define __pte_free_tlb(tlb,pte) tlb_remove_page(tlb,pte)
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#endif /* _S390_PGALLOC_H */
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