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vm_tlb.c
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1 /*
2  * Hexagon Virtual Machine TLB functions
3  *
4  * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 and
8  * only version 2 as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18  * 02110-1301, USA.
19  */
20 
21 /*
22  * The Hexagon Virtual Machine conceals the real workings of
23  * the TLB, but there are one or two functions that need to
24  * be instantiated for it, differently from a native build.
25  */
26 #include <linux/mm.h>
27 #include <asm/page.h>
28 #include <asm/hexagon_vm.h>
29 
30 /*
31  * Initial VM implementation has only one map active at a time, with
32  * TLB purgings on changes. So either we're nuking the current map,
33  * or it's a no-op. This operation is messy on true SMPs where other
34  * processors must be induced to flush the copies in their local TLBs,
35  * but Hexagon thread-based virtual processors share the same MMU.
36  */
37 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
38  unsigned long end)
39 {
40  struct mm_struct *mm = vma->vm_mm;
41 
42  if (mm->context.ptbase == current->active_mm->context.ptbase)
43  __vmclrmap((void *)start, end - start);
44 }
45 
46 /*
47  * Flush a page from the kernel virtual map - used by highmem
48  */
49 void flush_tlb_one(unsigned long vaddr)
50 {
51  __vmclrmap((void *)vaddr, PAGE_SIZE);
52 }
53 
54 /*
55  * Flush all TLBs across all CPUs, virtual or real.
56  * A single Hexagon core has 6 thread contexts but
57  * only one TLB.
58  */
59 void tlb_flush_all(void)
60 {
61  /* should probably use that fixaddr end or whateve label */
62  __vmclrmap(0, 0xffff0000);
63 }
64 
65 /*
66  * Flush TLB entries associated with a given mm_struct mapping.
67  */
68 void flush_tlb_mm(struct mm_struct *mm)
69 {
70  /* Current Virtual Machine has only one map active at a time */
71  if (current->active_mm->context.ptbase == mm->context.ptbase)
72  tlb_flush_all();
73 }
74 
75 /*
76  * Flush TLB state associated with a page of a vma.
77  */
78 void flush_tlb_page(struct vm_area_struct *vma, unsigned long vaddr)
79 {
80  struct mm_struct *mm = vma->vm_mm;
81 
82  if (mm->context.ptbase == current->active_mm->context.ptbase)
83  __vmclrmap((void *)vaddr, PAGE_SIZE);
84 }
85 
86 /*
87  * Flush TLB entries associated with a kernel address range.
88  * Like flush range, but without the check on the vma->vm_mm.
89  */
90 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
91 {
92  __vmclrmap((void *)start, end - start);
93 }