1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _S390_TLB_H 3 #define _S390_TLB_H 4 5 /* 6 * TLB flushing on s390 is complicated. The following requirement 7 * from the principles of operation is the most arduous: 8 * 9 * "A valid table entry must not be changed while it is attached 10 * to any CPU and may be used for translation by that CPU except to 11 * (1) invalidate the entry by using INVALIDATE PAGE TABLE ENTRY, 12 * or INVALIDATE DAT TABLE ENTRY, (2) alter bits 56-63 of a page 13 * table entry, or (3) make a change by means of a COMPARE AND SWAP 14 * AND PURGE instruction that purges the TLB." 15 * 16 * The modification of a pte of an active mm struct therefore is 17 * a two step process: i) invalidate the pte, ii) store the new pte. 18 * This is true for the page protection bit as well. 19 * The only possible optimization is to flush at the beginning of 20 * a tlb_gather_mmu cycle if the mm_struct is currently not in use. 21 * 22 * Pages used for the page tables is a different story. FIXME: more 23 */ 24 25 void __tlb_remove_table(void *_table); 26 static inline void tlb_flush(struct mmu_gather *tlb); 27 static inline bool __tlb_remove_page_size(struct mmu_gather *tlb, 28 struct page *page, int page_size); 29 30 #define tlb_start_vma(tlb, vma) do { } while (0) 31 #define tlb_end_vma(tlb, vma) do { } while (0) 32 33 #define tlb_flush tlb_flush 34 #define pte_free_tlb pte_free_tlb 35 #define pmd_free_tlb pmd_free_tlb 36 #define p4d_free_tlb p4d_free_tlb 37 #define pud_free_tlb pud_free_tlb 38 39 #include <asm/pgalloc.h> 40 #include <asm/tlbflush.h> 41 #include <asm-generic/tlb.h> 42 43 /* 44 * Release the page cache reference for a pte removed by 45 * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page 46 * has already been freed, so just do free_page_and_swap_cache. 47 */ 48 static inline bool __tlb_remove_page_size(struct mmu_gather *tlb, 49 struct page *page, int page_size) 50 { 51 free_page_and_swap_cache(page); 52 return false; 53 } 54 55 static inline void tlb_flush(struct mmu_gather *tlb) 56 { 57 __tlb_flush_mm_lazy(tlb->mm); 58 } 59 60 /* 61 * pte_free_tlb frees a pte table and clears the CRSTE for the 62 * page table from the tlb. 63 */ 64 static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, 65 unsigned long address) 66 { 67 __tlb_adjust_range(tlb, address, PAGE_SIZE); 68 tlb->mm->context.flush_mm = 1; 69 tlb->freed_tables = 1; 70 tlb->cleared_ptes = 1; 71 /* 72 * page_table_free_rcu takes care of the allocation bit masks 73 * of the 2K table fragments in the 4K page table page, 74 * then calls tlb_remove_table. 75 */ 76 page_table_free_rcu(tlb, (unsigned long *) pte, address); 77 } 78 79 /* 80 * pmd_free_tlb frees a pmd table and clears the CRSTE for the 81 * segment table entry from the tlb. 82 * If the mm uses a two level page table the single pmd is freed 83 * as the pgd. pmd_free_tlb checks the asce_limit against 2GB 84 * to avoid the double free of the pmd in this case. 85 */ 86 static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd, 87 unsigned long address) 88 { 89 if (mm_pmd_folded(tlb->mm)) 90 return; 91 pgtable_pmd_page_dtor(virt_to_page(pmd)); 92 __tlb_adjust_range(tlb, address, PAGE_SIZE); 93 tlb->mm->context.flush_mm = 1; 94 tlb->freed_tables = 1; 95 tlb->cleared_puds = 1; 96 tlb_remove_table(tlb, pmd); 97 } 98 99 /* 100 * p4d_free_tlb frees a pud table and clears the CRSTE for the 101 * region second table entry from the tlb. 102 * If the mm uses a four level page table the single p4d is freed 103 * as the pgd. p4d_free_tlb checks the asce_limit against 8PB 104 * to avoid the double free of the p4d in this case. 105 */ 106 static inline void p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d, 107 unsigned long address) 108 { 109 if (mm_p4d_folded(tlb->mm)) 110 return; 111 __tlb_adjust_range(tlb, address, PAGE_SIZE); 112 tlb->mm->context.flush_mm = 1; 113 tlb->freed_tables = 1; 114 tlb->cleared_p4ds = 1; 115 tlb_remove_table(tlb, p4d); 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 if (mm_pud_folded(tlb->mm)) 129 return; 130 tlb->mm->context.flush_mm = 1; 131 tlb->freed_tables = 1; 132 tlb->cleared_puds = 1; 133 tlb_remove_table(tlb, pud); 134 } 135 136 137 #endif /* _S390_TLB_H */ 138