xref: /openbmc/linux/arch/um/include/asm/tlb.h (revision 5bd8e16d)
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(struct mmu_gather *tlb)
63 {
64 	if (!tlb->need_flush)
65 		return;
66 
67 	flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end);
68 	init_tlb_gather(tlb);
69 }
70 
71 /* tlb_finish_mmu
72  *	Called at the end of the shootdown operation to free up any resources
73  *	that were required.
74  */
75 static inline void
76 tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
77 {
78 	tlb_flush_mmu(tlb);
79 
80 	/* keep the page table cache within bounds */
81 	check_pgt_cache();
82 }
83 
84 /* tlb_remove_page
85  *	Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)),
86  *	while handling the additional races in SMP caused by other CPUs
87  *	caching valid mappings in their TLBs.
88  */
89 static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
90 {
91 	tlb->need_flush = 1;
92 	free_page_and_swap_cache(page);
93 	return 1; /* avoid calling tlb_flush_mmu */
94 }
95 
96 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
97 {
98 	__tlb_remove_page(tlb, page);
99 }
100 
101 /**
102  * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
103  *
104  * Record the fact that pte's were really umapped in ->need_flush, so we can
105  * later optimise away the tlb invalidate.   This helps when userspace is
106  * unmapping already-unmapped pages, which happens quite a lot.
107  */
108 #define tlb_remove_tlb_entry(tlb, ptep, address)		\
109 	do {							\
110 		tlb->need_flush = 1;				\
111 		__tlb_remove_tlb_entry(tlb, ptep, address);	\
112 	} while (0)
113 
114 #define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr)
115 
116 #define pud_free_tlb(tlb, pudp, addr) __pud_free_tlb(tlb, pudp, addr)
117 
118 #define pmd_free_tlb(tlb, pmdp, addr) __pmd_free_tlb(tlb, pmdp, addr)
119 
120 #define tlb_migrate_finish(mm) do {} while (0)
121 
122 #endif
123