1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6 #ifndef __UM_TLBFLUSH_H
7 #define __UM_TLBFLUSH_H
8
9 #include <linux/mm.h>
10
11 /*
12 * In UML, we need to sync the TLB over by using mmap/munmap/mprotect syscalls
13 * from the process handling the MM (which can be the kernel itself).
14 *
15 * To track updates, we can hook into set_ptes and flush_tlb_*. With set_ptes
16 * we catch all PTE transitions where memory that was unusable becomes usable.
17 * While with flush_tlb_* we can track any memory that becomes unusable and
18 * even if a higher layer of the page table was modified.
19 *
20 * So, we simply track updates using both methods and mark the memory area to
21 * be synced later on. The only special case is that flush_tlb_kern_* needs to
22 * be executed immediately as there is no good synchronization point in that
23 * case. In contrast, in the set_ptes case we can wait for the next kernel
24 * segfault before we do the synchornization.
25 *
26 * - flush_tlb_all() flushes all processes TLBs
27 * - flush_tlb_mm(mm) flushes the specified mm context TLB's
28 * - flush_tlb_page(vma, vmaddr) flushes one page
29 * - flush_tlb_range(vma, start, end) flushes a range of pages
30 * - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
31 */
32
33 extern int um_tlb_sync(struct mm_struct *mm);
34
35 extern void flush_tlb_all(void);
36 extern void flush_tlb_mm(struct mm_struct *mm);
37
38 static inline void flush_tlb_page(struct vm_area_struct *vma,
39 unsigned long address)
40 {
41 um_tlb_mark_sync(vma->vm_mm, address, address + PAGE_SIZE);
42 }
43
44 static inline void flush_tlb_range(struct vm_area_struct *vma,
45 unsigned long start, unsigned long end)
46 {
47 um_tlb_mark_sync(vma->vm_mm, start, end);
48 }
49
50 static inline void flush_tlb_kernel_range(unsigned long start,
51 unsigned long end)
52 {
53 um_tlb_mark_sync(&init_mm, start, end);
54
55 /* Kernel needs to be synced immediately */
56 um_tlb_sync(&init_mm);
57 }
58
59 #endif
60
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