1 #ifndef _S390_TLB_H 2 #define _S390_TLB_H 3 4 /* 5 * TLB flushing on s390 is complicated. The following requirement 6 * from the principles of operation is the most arduous: 7 * 8 * "A valid table entry must not be changed while it is attached 9 * to any CPU and may be used for translation by that CPU except to 10 * (1) invalidate the entry by using INVALIDATE PAGE TABLE ENTRY, 11 * or INVALIDATE DAT TABLE ENTRY, (2) alter bits 56-63 of a page 12 * table entry, or (3) make a change by means of a COMPARE AND SWAP 13 * AND PURGE instruction that purges the TLB." 14 * 15 * The modification of a pte of an active mm struct therefore is 16 * a two step process: i) invalidate the pte, ii) store the new pte. 17 * This is true for the page protection bit as well. 18 * The only possible optimization is to flush at the beginning of 19 * a tlb_gather_mmu cycle if the mm_struct is currently not in use. 20 * 21 * Pages used for the page tables is a different story. FIXME: more 22 */ 23 24 #include <linux/mm.h> 25 #include <linux/pagemap.h> 26 #include <linux/swap.h> 27 #include <asm/processor.h> 28 #include <asm/pgalloc.h> 29 #include <asm/tlbflush.h> 30 31 struct mmu_gather { 32 struct mm_struct *mm; 33 struct mmu_table_batch *batch; 34 unsigned int fullmm; 35 unsigned long start, end; 36 }; 37 38 struct mmu_table_batch { 39 struct rcu_head rcu; 40 unsigned int nr; 41 void *tables[0]; 42 }; 43 44 #define MAX_TABLE_BATCH \ 45 ((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *)) 46 47 extern void tlb_table_flush(struct mmu_gather *tlb); 48 extern void tlb_remove_table(struct mmu_gather *tlb, void *table); 49 50 static inline void tlb_gather_mmu(struct mmu_gather *tlb, 51 struct mm_struct *mm, 52 unsigned long start, 53 unsigned long end) 54 { 55 tlb->mm = mm; 56 tlb->start = start; 57 tlb->end = end; 58 tlb->fullmm = !(start | (end+1)); 59 tlb->batch = NULL; 60 } 61 62 static inline void tlb_flush_mmu(struct mmu_gather *tlb) 63 { 64 __tlb_flush_mm_lazy(tlb->mm); 65 tlb_table_flush(tlb); 66 } 67 68 static inline void tlb_finish_mmu(struct mmu_gather *tlb, 69 unsigned long start, unsigned long end) 70 { 71 tlb_flush_mmu(tlb); 72 } 73 74 /* 75 * Release the page cache reference for a pte removed by 76 * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page 77 * has already been freed, so just do free_page_and_swap_cache. 78 */ 79 static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page) 80 { 81 free_page_and_swap_cache(page); 82 return 1; /* avoid calling tlb_flush_mmu */ 83 } 84 85 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) 86 { 87 free_page_and_swap_cache(page); 88 } 89 90 /* 91 * pte_free_tlb frees a pte table and clears the CRSTE for the 92 * page table from the tlb. 93 */ 94 static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, 95 unsigned long address) 96 { 97 page_table_free_rcu(tlb, (unsigned long *) pte); 98 } 99 100 /* 101 * pmd_free_tlb frees a pmd table and clears the CRSTE for the 102 * segment table entry from the tlb. 103 * If the mm uses a two level page table the single pmd is freed 104 * as the pgd. pmd_free_tlb checks the asce_limit against 2GB 105 * to avoid the double free of the pmd in this case. 106 */ 107 static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd, 108 unsigned long address) 109 { 110 #ifdef CONFIG_64BIT 111 if (tlb->mm->context.asce_limit <= (1UL << 31)) 112 return; 113 tlb_remove_table(tlb, pmd); 114 #endif 115 } 116 117 /* 118 * pud_free_tlb frees a pud table and clears the CRSTE for the 119 * region third table entry from the tlb. 120 * If the mm uses a three level page table the single pud is freed 121 * as the pgd. pud_free_tlb checks the asce_limit against 4TB 122 * to avoid the double free of the pud in this case. 123 */ 124 static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud, 125 unsigned long address) 126 { 127 #ifdef CONFIG_64BIT 128 if (tlb->mm->context.asce_limit <= (1UL << 42)) 129 return; 130 tlb_remove_table(tlb, pud); 131 #endif 132 } 133 134 #define tlb_start_vma(tlb, vma) do { } while (0) 135 #define tlb_end_vma(tlb, vma) do { } while (0) 136 #define tlb_remove_tlb_entry(tlb, ptep, addr) do { } while (0) 137 #define tlb_remove_pmd_tlb_entry(tlb, pmdp, addr) do { } while (0) 138 #define tlb_migrate_finish(mm) do { } while (0) 139 140 #endif /* _S390_TLB_H */ 141