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_flush tlb_flush 31 #define pte_free_tlb pte_free_tlb 32 #define pmd_free_tlb pmd_free_tlb 33 #define p4d_free_tlb p4d_free_tlb 34 #define pud_free_tlb pud_free_tlb 35 36 #include <asm/tlbflush.h> 37 #include <asm-generic/tlb.h> 38 39 /* 40 * Release the page cache reference for a pte removed by 41 * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page 42 * has already been freed, so just do free_page_and_swap_cache. 43 */ 44 static inline bool __tlb_remove_page_size(struct mmu_gather *tlb, 45 struct page *page, int page_size) 46 { 47 free_page_and_swap_cache(page); 48 return false; 49 } 50 51 static inline void tlb_flush(struct mmu_gather *tlb) 52 { 53 __tlb_flush_mm_lazy(tlb->mm); 54 } 55 56 /* 57 * pte_free_tlb frees a pte table and clears the CRSTE for the 58 * page table from the tlb. 59 */ 60 static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, 61 unsigned long address) 62 { 63 __tlb_adjust_range(tlb, address, PAGE_SIZE); 64 tlb->mm->context.flush_mm = 1; 65 tlb->freed_tables = 1; 66 tlb->cleared_pmds = 1; 67 /* 68 * page_table_free_rcu takes care of the allocation bit masks 69 * of the 2K table fragments in the 4K page table page, 70 * then calls tlb_remove_table. 71 */ 72 page_table_free_rcu(tlb, (unsigned long *) pte, address); 73 } 74 75 /* 76 * pmd_free_tlb frees a pmd table and clears the CRSTE for the 77 * segment table entry from the tlb. 78 * If the mm uses a two level page table the single pmd is freed 79 * as the pgd. pmd_free_tlb checks the asce_limit against 2GB 80 * to avoid the double free of the pmd in this case. 81 */ 82 static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd, 83 unsigned long address) 84 { 85 if (mm_pmd_folded(tlb->mm)) 86 return; 87 pgtable_pmd_page_dtor(virt_to_page(pmd)); 88 __tlb_adjust_range(tlb, address, PAGE_SIZE); 89 tlb->mm->context.flush_mm = 1; 90 tlb->freed_tables = 1; 91 tlb->cleared_puds = 1; 92 tlb_remove_table(tlb, pmd); 93 } 94 95 /* 96 * p4d_free_tlb frees a pud table and clears the CRSTE for the 97 * region second table entry from the tlb. 98 * If the mm uses a four level page table the single p4d is freed 99 * as the pgd. p4d_free_tlb checks the asce_limit against 8PB 100 * to avoid the double free of the p4d in this case. 101 */ 102 static inline void p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d, 103 unsigned long address) 104 { 105 if (mm_p4d_folded(tlb->mm)) 106 return; 107 __tlb_adjust_range(tlb, address, PAGE_SIZE); 108 tlb->mm->context.flush_mm = 1; 109 tlb->freed_tables = 1; 110 tlb_remove_table(tlb, p4d); 111 } 112 113 /* 114 * pud_free_tlb frees a pud table and clears the CRSTE for the 115 * region third table entry from the tlb. 116 * If the mm uses a three level page table the single pud is freed 117 * as the pgd. pud_free_tlb checks the asce_limit against 4TB 118 * to avoid the double free of the pud in this case. 119 */ 120 static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud, 121 unsigned long address) 122 { 123 if (mm_pud_folded(tlb->mm)) 124 return; 125 tlb->mm->context.flush_mm = 1; 126 tlb->freed_tables = 1; 127 tlb->cleared_p4ds = 1; 128 tlb_remove_table(tlb, pud); 129 } 130 131 132 #endif /* _S390_TLB_H */ 133