136 lines
4.2 KiB
C
136 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#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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void __tlb_remove_table(void *_table);
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static inline void tlb_flush(struct mmu_gather *tlb);
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static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
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struct page *page, int page_size);
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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_flush tlb_flush
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#define pte_free_tlb pte_free_tlb
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#define pmd_free_tlb pmd_free_tlb
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#define p4d_free_tlb p4d_free_tlb
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#define pud_free_tlb pud_free_tlb
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#include <asm/tlbflush.h>
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#include <asm-generic/tlb.h>
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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 bool __tlb_remove_page_size(struct mmu_gather *tlb,
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struct page *page, int page_size)
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{
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free_page_and_swap_cache(page);
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return false;
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}
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static inline void tlb_flush(struct mmu_gather *tlb)
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{
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__tlb_flush_mm_lazy(tlb->mm);
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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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__tlb_adjust_range(tlb, address, PAGE_SIZE);
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tlb->mm->context.flush_mm = 1;
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tlb->freed_tables = 1;
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tlb->cleared_pmds = 1;
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/*
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* page_table_free_rcu takes care of the allocation bit masks
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* of the 2K table fragments in the 4K page table page,
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* then calls tlb_remove_table.
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*/
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page_table_free_rcu(tlb, (unsigned long *) pte, address);
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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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if (mm_pmd_folded(tlb->mm))
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return;
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pgtable_pmd_page_dtor(virt_to_page(pmd));
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__tlb_adjust_range(tlb, address, PAGE_SIZE);
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tlb->mm->context.flush_mm = 1;
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tlb->freed_tables = 1;
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tlb->cleared_puds = 1;
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tlb_remove_table(tlb, pmd);
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}
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/*
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* p4d_free_tlb frees a pud table and clears the CRSTE for the
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* region second table entry from the tlb.
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* If the mm uses a four level page table the single p4d is freed
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* as the pgd. p4d_free_tlb checks the asce_limit against 8PB
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* to avoid the double free of the p4d in this case.
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*/
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static inline void p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d,
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unsigned long address)
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{
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if (mm_p4d_folded(tlb->mm))
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return;
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__tlb_adjust_range(tlb, address, PAGE_SIZE);
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tlb->mm->context.flush_mm = 1;
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tlb->freed_tables = 1;
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tlb_remove_table(tlb, p4d);
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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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if (mm_pud_folded(tlb->mm))
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return;
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tlb->mm->context.flush_mm = 1;
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tlb->freed_tables = 1;
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tlb->cleared_p4ds = 1;
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tlb_remove_table(tlb, pud);
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}
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#endif /* _S390_TLB_H */
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