From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/s390/include/asm/tlb.h | 148 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 148 insertions(+) create mode 100644 arch/s390/include/asm/tlb.h (limited to 'arch/s390/include/asm/tlb.h') diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h new file mode 100644 index 000000000..7a92e69c5 --- /dev/null +++ b/arch/s390/include/asm/tlb.h @@ -0,0 +1,148 @@ +#ifndef _S390_TLB_H +#define _S390_TLB_H + +/* + * TLB flushing on s390 is complicated. The following requirement + * from the principles of operation is the most arduous: + * + * "A valid table entry must not be changed while it is attached + * to any CPU and may be used for translation by that CPU except to + * (1) invalidate the entry by using INVALIDATE PAGE TABLE ENTRY, + * or INVALIDATE DAT TABLE ENTRY, (2) alter bits 56-63 of a page + * table entry, or (3) make a change by means of a COMPARE AND SWAP + * AND PURGE instruction that purges the TLB." + * + * The modification of a pte of an active mm struct therefore is + * a two step process: i) invalidate the pte, ii) store the new pte. + * This is true for the page protection bit as well. + * The only possible optimization is to flush at the beginning of + * a tlb_gather_mmu cycle if the mm_struct is currently not in use. + * + * Pages used for the page tables is a different story. FIXME: more + */ + +#include +#include +#include +#include +#include +#include + +struct mmu_gather { + struct mm_struct *mm; + struct mmu_table_batch *batch; + unsigned int fullmm; + unsigned long start, end; +}; + +struct mmu_table_batch { + struct rcu_head rcu; + unsigned int nr; + void *tables[0]; +}; + +#define MAX_TABLE_BATCH \ + ((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *)) + +extern void tlb_table_flush(struct mmu_gather *tlb); +extern void tlb_remove_table(struct mmu_gather *tlb, void *table); + +static inline void tlb_gather_mmu(struct mmu_gather *tlb, + struct mm_struct *mm, + unsigned long start, + unsigned long end) +{ + tlb->mm = mm; + tlb->start = start; + tlb->end = end; + tlb->fullmm = !(start | (end+1)); + tlb->batch = NULL; +} + +static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) +{ + __tlb_flush_mm_lazy(tlb->mm); +} + +static inline void tlb_flush_mmu_free(struct mmu_gather *tlb) +{ + tlb_table_flush(tlb); +} + + +static inline void tlb_flush_mmu(struct mmu_gather *tlb) +{ + tlb_flush_mmu_tlbonly(tlb); + tlb_flush_mmu_free(tlb); +} + +static inline void tlb_finish_mmu(struct mmu_gather *tlb, + unsigned long start, unsigned long end) +{ + tlb_flush_mmu(tlb); +} + +/* + * Release the page cache reference for a pte removed by + * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page + * has already been freed, so just do free_page_and_swap_cache. + */ +static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page) +{ + free_page_and_swap_cache(page); + return 1; /* avoid calling tlb_flush_mmu */ +} + +static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) +{ + free_page_and_swap_cache(page); +} + +/* + * pte_free_tlb frees a pte table and clears the CRSTE for the + * page table from the tlb. + */ +static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, + unsigned long address) +{ + page_table_free_rcu(tlb, (unsigned long *) pte, address); +} + +/* + * pmd_free_tlb frees a pmd table and clears the CRSTE for the + * segment table entry from the tlb. + * If the mm uses a two level page table the single pmd is freed + * as the pgd. pmd_free_tlb checks the asce_limit against 2GB + * to avoid the double free of the pmd in this case. + */ +static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd, + unsigned long address) +{ + if (tlb->mm->context.asce_limit <= (1UL << 31)) + return; + pgtable_pmd_page_dtor(virt_to_page(pmd)); + tlb_remove_table(tlb, pmd); +} + +/* + * pud_free_tlb frees a pud table and clears the CRSTE for the + * region third table entry from the tlb. + * If the mm uses a three level page table the single pud is freed + * as the pgd. pud_free_tlb checks the asce_limit against 4TB + * to avoid the double free of the pud in this case. + */ +static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud, + unsigned long address) +{ + if (tlb->mm->context.asce_limit <= (1UL << 42)) + return; + tlb_remove_table(tlb, pud); +} + +#define tlb_start_vma(tlb, vma) do { } while (0) +#define tlb_end_vma(tlb, vma) do { } while (0) +#define tlb_remove_tlb_entry(tlb, ptep, addr) do { } while (0) +#define tlb_remove_pmd_tlb_entry(tlb, pmdp, addr) do { } while (0) +#define tlb_migrate_finish(mm) do { } while (0) + +#endif /* _S390_TLB_H */ -- cgit v1.2.3-54-g00ecf