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_tlbonly(struct mmu_gather *tlb) 63 { 64 __tlb_flush_mm_lazy(tlb->mm); 65 } 66 67 static inline void tlb_flush_mmu_free(struct mmu_gather *tlb) 68 { 69 tlb_table_flush(tlb); 70 } 71 72 73 static inline void tlb_flush_mmu(struct mmu_gather *tlb) 74 { 75 tlb_flush_mmu_tlbonly(tlb); 76 tlb_flush_mmu_free(tlb); 77 } 78 79 static inline void tlb_finish_mmu(struct mmu_gather *tlb, 80 unsigned long start, unsigned long end) 81 { 82 tlb_flush_mmu(tlb); 83 } 84 85 /* 86 * Release the page cache reference for a pte removed by 87 * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page 88 * has already been freed, so just do free_page_and_swap_cache. 89 */ 90 static inline bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page) 91 { 92 free_page_and_swap_cache(page); 93 return false; /* avoid calling tlb_flush_mmu */ 94 } 95 96 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) 97 { 98 free_page_and_swap_cache(page); 99 } 100 101 static inline bool __tlb_remove_page_size(struct mmu_gather *tlb, 102 struct page *page, int page_size) 103 { 104 return __tlb_remove_page(tlb, page); 105 } 106 107 static inline void tlb_remove_page_size(struct mmu_gather *tlb, 108 struct page *page, int page_size) 109 { 110 return tlb_remove_page(tlb, page); 111 } 112 113 /* 114 * pte_free_tlb frees a pte table and clears the CRSTE for the 115 * page table from the tlb. 116 */ 117 static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, 118 unsigned long address) 119 { 120 page_table_free_rcu(tlb, (unsigned long *) pte, address); 121 } 122 123 /* 124 * pmd_free_tlb frees a pmd table and clears the CRSTE for the 125 * segment table entry from the tlb. 126 * If the mm uses a two level page table the single pmd is freed 127 * as the pgd. pmd_free_tlb checks the asce_limit against 2GB 128 * to avoid the double free of the pmd in this case. 129 */ 130 static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd, 131 unsigned long address) 132 { 133 if (tlb->mm->context.asce_limit <= (1UL << 31)) 134 return; 135 pgtable_pmd_page_dtor(virt_to_page(pmd)); 136 tlb_remove_table(tlb, pmd); 137 } 138 139 /* 140 * p4d_free_tlb frees a pud table and clears the CRSTE for the 141 * region second table entry from the tlb. 142 * If the mm uses a four level page table the single p4d is freed 143 * as the pgd. p4d_free_tlb checks the asce_limit against 8PB 144 * to avoid the double free of the p4d in this case. 145 */ 146 static inline void p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d, 147 unsigned long address) 148 { 149 if (tlb->mm->context.asce_limit <= (1UL << 53)) 150 return; 151 tlb_remove_table(tlb, p4d); 152 } 153 154 /* 155 * pud_free_tlb frees a pud table and clears the CRSTE for the 156 * region third table entry from the tlb. 157 * If the mm uses a three level page table the single pud is freed 158 * as the pgd. pud_free_tlb checks the asce_limit against 4TB 159 * to avoid the double free of the pud in this case. 160 */ 161 static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud, 162 unsigned long address) 163 { 164 if (tlb->mm->context.asce_limit <= (1UL << 42)) 165 return; 166 tlb_remove_table(tlb, pud); 167 } 168 169 #define tlb_start_vma(tlb, vma) do { } while (0) 170 #define tlb_end_vma(tlb, vma) do { } while (0) 171 #define tlb_remove_tlb_entry(tlb, ptep, addr) do { } while (0) 172 #define tlb_remove_pmd_tlb_entry(tlb, pmdp, addr) do { } while (0) 173 #define tlb_migrate_finish(mm) do { } while (0) 174 #define tlb_remove_huge_tlb_entry(h, tlb, ptep, address) \ 175 tlb_remove_tlb_entry(tlb, ptep, address) 176 177 #define tlb_remove_check_page_size_change tlb_remove_check_page_size_change 178 static inline void tlb_remove_check_page_size_change(struct mmu_gather *tlb, 179 unsigned int page_size) 180 { 181 } 182 183 #endif /* _S390_TLB_H */ 184