163 строки
4.5 KiB
C
163 строки
4.5 KiB
C
#ifndef _S390_TLB_H
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#define _S390_TLB_H
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/*
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* TLB flushing on s390 is complicated. The following requirement
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* from the principles of operation is the most arduous:
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*
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* "A valid table entry must not be changed while it is attached
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* to any CPU and may be used for translation by that CPU except to
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* (1) invalidate the entry by using INVALIDATE PAGE TABLE ENTRY,
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* or INVALIDATE DAT TABLE ENTRY, (2) alter bits 56-63 of a page
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* table entry, or (3) make a change by means of a COMPARE AND SWAP
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* AND PURGE instruction that purges the TLB."
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*
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* The modification of a pte of an active mm struct therefore is
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* a two step process: i) invalidate the pte, ii) store the new pte.
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* This is true for the page protection bit as well.
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* The only possible optimization is to flush at the beginning of
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* a tlb_gather_mmu cycle if the mm_struct is currently not in use.
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*
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* Pages used for the page tables is a different story. FIXME: more
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*/
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include <linux/swap.h>
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#include <asm/processor.h>
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#include <asm/pgalloc.h>
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#include <asm/tlbflush.h>
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struct mmu_gather {
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struct mm_struct *mm;
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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struct mmu_table_batch *batch;
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#endif
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unsigned int fullmm;
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unsigned int need_flush;
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};
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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struct mmu_table_batch {
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struct rcu_head rcu;
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unsigned int nr;
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void *tables[0];
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};
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#define MAX_TABLE_BATCH \
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((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
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extern void tlb_table_flush(struct mmu_gather *tlb);
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extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
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#endif
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static inline void tlb_gather_mmu(struct mmu_gather *tlb,
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struct mm_struct *mm,
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unsigned int full_mm_flush)
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{
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tlb->mm = mm;
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tlb->fullmm = full_mm_flush;
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tlb->need_flush = 0;
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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tlb->batch = NULL;
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#endif
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if (tlb->fullmm)
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__tlb_flush_mm(mm);
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}
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static inline void tlb_flush_mmu(struct mmu_gather *tlb)
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{
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if (!tlb->need_flush)
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return;
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tlb->need_flush = 0;
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__tlb_flush_mm(tlb->mm);
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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tlb_table_flush(tlb);
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#endif
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}
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static inline void tlb_finish_mmu(struct mmu_gather *tlb,
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unsigned long start, unsigned long end)
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{
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tlb_flush_mmu(tlb);
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}
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/*
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* Release the page cache reference for a pte removed by
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* tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page
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* has already been freed, so just do free_page_and_swap_cache.
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*/
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static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
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{
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free_page_and_swap_cache(page);
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return 1; /* avoid calling tlb_flush_mmu */
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}
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static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
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{
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free_page_and_swap_cache(page);
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}
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/*
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* pte_free_tlb frees a pte table and clears the CRSTE for the
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* page table from the tlb.
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*/
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static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
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unsigned long address)
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{
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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if (!tlb->fullmm)
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return page_table_free_rcu(tlb, (unsigned long *) pte);
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#endif
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page_table_free(tlb->mm, (unsigned long *) pte);
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}
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/*
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* pmd_free_tlb frees a pmd table and clears the CRSTE for the
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* segment table entry from the tlb.
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* If the mm uses a two level page table the single pmd is freed
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* as the pgd. pmd_free_tlb checks the asce_limit against 2GB
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* to avoid the double free of the pmd in this case.
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*/
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static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
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unsigned long address)
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{
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#ifdef __s390x__
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if (tlb->mm->context.asce_limit <= (1UL << 31))
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return;
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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if (!tlb->fullmm)
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return tlb_remove_table(tlb, pmd);
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#endif
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crst_table_free(tlb->mm, (unsigned long *) pmd);
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#endif
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}
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/*
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* pud_free_tlb frees a pud table and clears the CRSTE for the
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* region third table entry from the tlb.
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* If the mm uses a three level page table the single pud is freed
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* as the pgd. pud_free_tlb checks the asce_limit against 4TB
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* to avoid the double free of the pud in this case.
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*/
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static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
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unsigned long address)
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{
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#ifdef __s390x__
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if (tlb->mm->context.asce_limit <= (1UL << 42))
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return;
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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if (!tlb->fullmm)
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return tlb_remove_table(tlb, pud);
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#endif
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crst_table_free(tlb->mm, (unsigned long *) pud);
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#endif
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}
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#define tlb_start_vma(tlb, vma) do { } while (0)
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#define tlb_end_vma(tlb, vma) do { } while (0)
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#define tlb_remove_tlb_entry(tlb, ptep, addr) do { } while (0)
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#define tlb_migrate_finish(mm) do { } while (0)
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#endif /* _S390_TLB_H */
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