xref: /openbmc/linux/arch/hexagon/mm/vm_tlb.c (revision 3213486f)
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 <linux/sched.h>
28 #include <asm/page.h>
29 #include <asm/hexagon_vm.h>
30 
31 /*
32  * Initial VM implementation has only one map active at a time, with
33  * TLB purgings on changes.  So either we're nuking the current map,
34  * or it's a no-op.  This operation is messy on true SMPs where other
35  * processors must be induced to flush the copies in their local TLBs,
36  * but Hexagon thread-based virtual processors share the same MMU.
37  */
38 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
39 			unsigned long end)
40 {
41 	struct mm_struct *mm = vma->vm_mm;
42 
43 	if (mm->context.ptbase == current->active_mm->context.ptbase)
44 		__vmclrmap((void *)start, end - start);
45 }
46 
47 /*
48  * Flush a page from the kernel virtual map - used by highmem
49  */
50 void flush_tlb_one(unsigned long vaddr)
51 {
52 	__vmclrmap((void *)vaddr, PAGE_SIZE);
53 }
54 
55 /*
56  * Flush all TLBs across all CPUs, virtual or real.
57  * A single Hexagon core has 6 thread contexts but
58  * only one TLB.
59  */
60 void tlb_flush_all(void)
61 {
62 	/*  should probably use that fixaddr end or whateve label  */
63 	__vmclrmap(0, 0xffff0000);
64 }
65 
66 /*
67  * Flush TLB entries associated with a given mm_struct mapping.
68  */
69 void flush_tlb_mm(struct mm_struct *mm)
70 {
71 	/* Current Virtual Machine has only one map active at a time */
72 	if (current->active_mm->context.ptbase == mm->context.ptbase)
73 		tlb_flush_all();
74 }
75 
76 /*
77  * Flush TLB state associated with a page of a vma.
78  */
79 void flush_tlb_page(struct vm_area_struct *vma, unsigned long vaddr)
80 {
81 	struct mm_struct *mm = vma->vm_mm;
82 
83 	if (mm->context.ptbase  == current->active_mm->context.ptbase)
84 		__vmclrmap((void *)vaddr, PAGE_SIZE);
85 }
86 
87 /*
88  * Flush TLB entries associated with a kernel address range.
89  * Like flush range, but without the check on the vma->vm_mm.
90  */
91 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
92 {
93 		__vmclrmap((void *)start, end - start);
94 }
95