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 encoded_page *page, 29 int page_size); 30 31 #define tlb_flush tlb_flush 32 #define pte_free_tlb pte_free_tlb 33 #define pmd_free_tlb pmd_free_tlb 34 #define p4d_free_tlb p4d_free_tlb 35 #define pud_free_tlb pud_free_tlb 36 37 #include <asm/tlbflush.h> 38 #include <asm-generic/tlb.h> 39 40 /* 41 * Release the page cache reference for a pte removed by 42 * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page 43 * has already been freed, so just do free_page_and_swap_cache. 44 * 45 * s390 doesn't delay rmap removal, so there is nothing encoded in 46 * the page pointer. 47 */ 48 static inline bool __tlb_remove_page_size(struct mmu_gather *tlb, 49 struct encoded_page *page, 50 int page_size) 51 { 52 free_page_and_swap_cache(encoded_page_ptr(page)); 53 return false; 54 } 55 56 static inline void tlb_flush(struct mmu_gather *tlb) 57 { 58 __tlb_flush_mm_lazy(tlb->mm); 59 } 60 61 /* 62 * pte_free_tlb frees a pte table and clears the CRSTE for the 63 * page table from the tlb. 64 */ 65 static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, 66 unsigned long address) 67 { 68 __tlb_adjust_range(tlb, address, PAGE_SIZE); 69 tlb->mm->context.flush_mm = 1; 70 tlb->freed_tables = 1; 71 tlb->cleared_pmds = 1; 72 /* 73 * page_table_free_rcu takes care of the allocation bit masks 74 * of the 2K table fragments in the 4K page table page, 75 * then calls tlb_remove_table. 76 */ 77 page_table_free_rcu(tlb, (unsigned long *) pte, address); 78 } 79 80 /* 81 * pmd_free_tlb frees a pmd table and clears the CRSTE for the 82 * segment table entry from the tlb. 83 * If the mm uses a two level page table the single pmd is freed 84 * as the pgd. pmd_free_tlb checks the asce_limit against 2GB 85 * to avoid the double free of the pmd in this case. 86 */ 87 static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd, 88 unsigned long address) 89 { 90 if (mm_pmd_folded(tlb->mm)) 91 return; 92 pgtable_pmd_page_dtor(virt_to_page(pmd)); 93 __tlb_adjust_range(tlb, address, PAGE_SIZE); 94 tlb->mm->context.flush_mm = 1; 95 tlb->freed_tables = 1; 96 tlb->cleared_puds = 1; 97 tlb_remove_table(tlb, pmd); 98 } 99 100 /* 101 * p4d_free_tlb frees a pud table and clears the CRSTE for the 102 * region second table entry from the tlb. 103 * If the mm uses a four level page table the single p4d is freed 104 * as the pgd. p4d_free_tlb checks the asce_limit against 8PB 105 * to avoid the double free of the p4d in this case. 106 */ 107 static inline void p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d, 108 unsigned long address) 109 { 110 if (mm_p4d_folded(tlb->mm)) 111 return; 112 __tlb_adjust_range(tlb, address, PAGE_SIZE); 113 tlb->mm->context.flush_mm = 1; 114 tlb->freed_tables = 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_p4ds = 1; 133 tlb_remove_table(tlb, pud); 134 } 135 136 137 #endif /* _S390_TLB_H */ 138