xref: /openbmc/linux/arch/um/include/asm/tlb.h (revision 612a462a)
1 #ifndef __UM_TLB_H
2 #define __UM_TLB_H
3 
4 #include <linux/pagemap.h>
5 #include <linux/swap.h>
6 #include <asm/percpu.h>
7 #include <asm/pgalloc.h>
8 #include <asm/tlbflush.h>
9 
10 #define tlb_start_vma(tlb, vma) do { } while (0)
11 #define tlb_end_vma(tlb, vma) do { } while (0)
12 #define tlb_flush(tlb) flush_tlb_mm((tlb)->mm)
13 
14 /* struct mmu_gather is an opaque type used by the mm code for passing around
15  * any data needed by arch specific code for tlb_remove_page.
16  */
17 struct mmu_gather {
18 	struct mm_struct	*mm;
19 	unsigned int		need_flush; /* Really unmapped some ptes? */
20 	unsigned long		start;
21 	unsigned long		end;
22 	unsigned int		fullmm; /* non-zero means full mm flush */
23 };
24 
25 static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,
26 					  unsigned long address)
27 {
28 	if (tlb->start > address)
29 		tlb->start = address;
30 	if (tlb->end < address + PAGE_SIZE)
31 		tlb->end = address + PAGE_SIZE;
32 }
33 
34 static inline void init_tlb_gather(struct mmu_gather *tlb)
35 {
36 	tlb->need_flush = 0;
37 
38 	tlb->start = TASK_SIZE;
39 	tlb->end = 0;
40 
41 	if (tlb->fullmm) {
42 		tlb->start = 0;
43 		tlb->end = TASK_SIZE;
44 	}
45 }
46 
47 static inline void
48 arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
49 		unsigned long start, unsigned long end)
50 {
51 	tlb->mm = mm;
52 	tlb->start = start;
53 	tlb->end = end;
54 	tlb->fullmm = !(start | (end+1));
55 
56 	init_tlb_gather(tlb);
57 }
58 
59 extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
60 			       unsigned long end);
61 
62 static inline void
63 tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
64 {
65 	flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end);
66 }
67 
68 static inline void
69 tlb_flush_mmu_free(struct mmu_gather *tlb)
70 {
71 	init_tlb_gather(tlb);
72 }
73 
74 static inline void
75 tlb_flush_mmu(struct mmu_gather *tlb)
76 {
77 	if (!tlb->need_flush)
78 		return;
79 
80 	tlb_flush_mmu_tlbonly(tlb);
81 	tlb_flush_mmu_free(tlb);
82 }
83 
84 /* arch_tlb_finish_mmu
85  *	Called at the end of the shootdown operation to free up any resources
86  *	that were required.
87  */
88 static inline void
89 arch_tlb_finish_mmu(struct mmu_gather *tlb,
90 		unsigned long start, unsigned long end, bool force)
91 {
92 	if (force) {
93 		tlb->start = start;
94 		tlb->end = end;
95 		tlb->need_flush = 1;
96 	}
97 	tlb_flush_mmu(tlb);
98 
99 	/* keep the page table cache within bounds */
100 	check_pgt_cache();
101 }
102 
103 /* tlb_remove_page
104  *	Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)),
105  *	while handling the additional races in SMP caused by other CPUs
106  *	caching valid mappings in their TLBs.
107  */
108 static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
109 {
110 	tlb->need_flush = 1;
111 	free_page_and_swap_cache(page);
112 	return false; /* avoid calling tlb_flush_mmu */
113 }
114 
115 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
116 {
117 	__tlb_remove_page(tlb, page);
118 }
119 
120 static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
121 					  struct page *page, int page_size)
122 {
123 	return __tlb_remove_page(tlb, page);
124 }
125 
126 static inline void tlb_remove_page_size(struct mmu_gather *tlb,
127 					struct page *page, int page_size)
128 {
129 	return tlb_remove_page(tlb, page);
130 }
131 
132 /**
133  * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
134  *
135  * Record the fact that pte's were really umapped in ->need_flush, so we can
136  * later optimise away the tlb invalidate.   This helps when userspace is
137  * unmapping already-unmapped pages, which happens quite a lot.
138  */
139 #define tlb_remove_tlb_entry(tlb, ptep, address)		\
140 	do {							\
141 		tlb->need_flush = 1;				\
142 		__tlb_remove_tlb_entry(tlb, ptep, address);	\
143 	} while (0)
144 
145 #define tlb_remove_huge_tlb_entry(h, tlb, ptep, address)	\
146 	tlb_remove_tlb_entry(tlb, ptep, address)
147 
148 #define tlb_remove_check_page_size_change tlb_remove_check_page_size_change
149 static inline void tlb_remove_check_page_size_change(struct mmu_gather *tlb,
150 						     unsigned int page_size)
151 {
152 }
153 
154 #define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr)
155 
156 #define pud_free_tlb(tlb, pudp, addr) __pud_free_tlb(tlb, pudp, addr)
157 
158 #define pmd_free_tlb(tlb, pmdp, addr) __pmd_free_tlb(tlb, pmdp, addr)
159 
160 #define tlb_migrate_finish(mm) do {} while (0)
161 
162 #endif
163