xref: /openbmc/linux/arch/um/include/asm/tlb.h (revision eb3fcf00)
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 tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
49 {
50 	tlb->mm = mm;
51 	tlb->start = start;
52 	tlb->end = end;
53 	tlb->fullmm = !(start | (end+1));
54 
55 	init_tlb_gather(tlb);
56 }
57 
58 extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
59 			       unsigned long end);
60 
61 static inline void
62 tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
63 {
64 	flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end);
65 }
66 
67 static inline void
68 tlb_flush_mmu_free(struct mmu_gather *tlb)
69 {
70 	init_tlb_gather(tlb);
71 }
72 
73 static inline void
74 tlb_flush_mmu(struct mmu_gather *tlb)
75 {
76 	if (!tlb->need_flush)
77 		return;
78 
79 	tlb_flush_mmu_tlbonly(tlb);
80 	tlb_flush_mmu_free(tlb);
81 }
82 
83 /* tlb_finish_mmu
84  *	Called at the end of the shootdown operation to free up any resources
85  *	that were required.
86  */
87 static inline void
88 tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
89 {
90 	tlb_flush_mmu(tlb);
91 
92 	/* keep the page table cache within bounds */
93 	check_pgt_cache();
94 }
95 
96 /* tlb_remove_page
97  *	Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)),
98  *	while handling the additional races in SMP caused by other CPUs
99  *	caching valid mappings in their TLBs.
100  */
101 static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
102 {
103 	tlb->need_flush = 1;
104 	free_page_and_swap_cache(page);
105 	return 1; /* avoid calling tlb_flush_mmu */
106 }
107 
108 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
109 {
110 	__tlb_remove_page(tlb, page);
111 }
112 
113 /**
114  * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
115  *
116  * Record the fact that pte's were really umapped in ->need_flush, so we can
117  * later optimise away the tlb invalidate.   This helps when userspace is
118  * unmapping already-unmapped pages, which happens quite a lot.
119  */
120 #define tlb_remove_tlb_entry(tlb, ptep, address)		\
121 	do {							\
122 		tlb->need_flush = 1;				\
123 		__tlb_remove_tlb_entry(tlb, ptep, address);	\
124 	} while (0)
125 
126 #define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr)
127 
128 #define pud_free_tlb(tlb, pudp, addr) __pud_free_tlb(tlb, pudp, addr)
129 
130 #define pmd_free_tlb(tlb, pmdp, addr) __pmd_free_tlb(tlb, pmdp, addr)
131 
132 #define tlb_migrate_finish(mm) do {} while (0)
133 
134 #endif
135