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 if (mm_alloc_pgste(tlb->mm)) 73 gmap_unlink(tlb->mm, (unsigned long *)pte, address); 74 tlb_remove_ptdesc(tlb, pte); 75 } 76 77 /* 78 * pmd_free_tlb frees a pmd table and clears the CRSTE for the 79 * segment table entry from the tlb. 80 * If the mm uses a two level page table the single pmd is freed 81 * as the pgd. pmd_free_tlb checks the asce_limit against 2GB 82 * to avoid the double free of the pmd in this case. 83 */ 84 static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd, 85 unsigned long address) 86 { 87 if (mm_pmd_folded(tlb->mm)) 88 return; 89 pagetable_pmd_dtor(virt_to_ptdesc(pmd)); 90 __tlb_adjust_range(tlb, address, PAGE_SIZE); 91 tlb->mm->context.flush_mm = 1; 92 tlb->freed_tables = 1; 93 tlb->cleared_puds = 1; 94 tlb_remove_ptdesc(tlb, pmd); 95 } 96 97 /* 98 * p4d_free_tlb frees a pud table and clears the CRSTE for the 99 * region second table entry from the tlb. 100 * If the mm uses a four level page table the single p4d is freed 101 * as the pgd. p4d_free_tlb checks the asce_limit against 8PB 102 * to avoid the double free of the p4d in this case. 103 */ 104 static inline void p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d, 105 unsigned long address) 106 { 107 if (mm_p4d_folded(tlb->mm)) 108 return; 109 __tlb_adjust_range(tlb, address, PAGE_SIZE); 110 tlb->mm->context.flush_mm = 1; 111 tlb->freed_tables = 1; 112 tlb_remove_ptdesc(tlb, p4d); 113 } 114 115 /* 116 * pud_free_tlb frees a pud table and clears the CRSTE for the 117 * region third table entry from the tlb. 118 * If the mm uses a three level page table the single pud is freed 119 * as the pgd. pud_free_tlb checks the asce_limit against 4TB 120 * to avoid the double free of the pud in this case. 121 */ 122 static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud, 123 unsigned long address) 124 { 125 if (mm_pud_folded(tlb->mm)) 126 return; 127 tlb->mm->context.flush_mm = 1; 128 tlb->freed_tables = 1; 129 tlb->cleared_p4ds = 1; 130 tlb_remove_ptdesc(tlb, pud); 131 } 132 133 134 #endif /* _S390_TLB_H */ 135