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 }; 36 37 struct mmu_table_batch { 38 struct rcu_head rcu; 39 unsigned int nr; 40 void *tables[0]; 41 }; 42 43 #define MAX_TABLE_BATCH \ 44 ((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *)) 45 46 extern void tlb_table_flush(struct mmu_gather *tlb); 47 extern void tlb_remove_table(struct mmu_gather *tlb, void *table); 48 49 static inline void tlb_gather_mmu(struct mmu_gather *tlb, 50 struct mm_struct *mm, 51 unsigned int full_mm_flush) 52 { 53 tlb->mm = mm; 54 tlb->fullmm = full_mm_flush; 55 tlb->batch = NULL; 56 if (tlb->fullmm) 57 __tlb_flush_mm(mm); 58 } 59 60 static inline void tlb_flush_mmu(struct mmu_gather *tlb) 61 { 62 tlb_table_flush(tlb); 63 } 64 65 static inline void tlb_finish_mmu(struct mmu_gather *tlb, 66 unsigned long start, unsigned long end) 67 { 68 tlb_table_flush(tlb); 69 } 70 71 /* 72 * Release the page cache reference for a pte removed by 73 * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page 74 * has already been freed, so just do free_page_and_swap_cache. 75 */ 76 static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page) 77 { 78 free_page_and_swap_cache(page); 79 return 1; /* avoid calling tlb_flush_mmu */ 80 } 81 82 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) 83 { 84 free_page_and_swap_cache(page); 85 } 86 87 /* 88 * pte_free_tlb frees a pte table and clears the CRSTE for the 89 * page table from the tlb. 90 */ 91 static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, 92 unsigned long address) 93 { 94 if (!tlb->fullmm) 95 return page_table_free_rcu(tlb, (unsigned long *) pte); 96 page_table_free(tlb->mm, (unsigned long *) pte); 97 } 98 99 /* 100 * pmd_free_tlb frees a pmd table and clears the CRSTE for the 101 * segment table entry from the tlb. 102 * If the mm uses a two level page table the single pmd is freed 103 * as the pgd. pmd_free_tlb checks the asce_limit against 2GB 104 * to avoid the double free of the pmd in this case. 105 */ 106 static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd, 107 unsigned long address) 108 { 109 #ifdef CONFIG_64BIT 110 if (tlb->mm->context.asce_limit <= (1UL << 31)) 111 return; 112 if (!tlb->fullmm) 113 return tlb_remove_table(tlb, pmd); 114 crst_table_free(tlb->mm, (unsigned long *) pmd); 115 #endif 116 } 117 118 /* 119 * pud_free_tlb frees a pud table and clears the CRSTE for the 120 * region third table entry from the tlb. 121 * If the mm uses a three level page table the single pud is freed 122 * as the pgd. pud_free_tlb checks the asce_limit against 4TB 123 * to avoid the double free of the pud in this case. 124 */ 125 static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud, 126 unsigned long address) 127 { 128 #ifdef CONFIG_64BIT 129 if (tlb->mm->context.asce_limit <= (1UL << 42)) 130 return; 131 if (!tlb->fullmm) 132 return tlb_remove_table(tlb, pud); 133 crst_table_free(tlb->mm, (unsigned long *) pud); 134 #endif 135 } 136 137 #define tlb_start_vma(tlb, vma) do { } while (0) 138 #define tlb_end_vma(tlb, vma) do { } while (0) 139 #define tlb_remove_tlb_entry(tlb, ptep, addr) do { } while (0) 140 #define tlb_remove_pmd_tlb_entry(tlb, pmdp, addr) do { } while (0) 141 #define tlb_migrate_finish(mm) do { } while (0) 142 143 #endif /* _S390_TLB_H */ 144