2
* linux/arch/cris/arch-v10/mm/tlb.c
4
* Low level TLB handling
7
* Copyright (C) 2000-2007 Axis Communications AB
9
* Authors: Bjorn Wesen (bjornw@axis.com)
14
#include <asm/mmu_context.h>
15
#include <arch/svinto.h>
19
/* The TLB can host up to 64 different mm contexts at the same time.
20
* The running context is R_MMU_CONTEXT, and each TLB entry contains a
21
* page_id that has to match to give a hit. In page_id_map, we keep track
22
* of which mm's we have assigned which page_id's, so that we know when
23
* to invalidate TLB entries.
25
* The last page_id is never running - it is used as an invalid page_id
26
* so we can make TLB entries that will never match.
28
* Notice that we need to make the flushes atomic, otherwise an interrupt
29
* handler that uses vmalloced memory might cause a TLB load in the middle
33
/* invalidate all TLB entries */
41
/* the vpn of i & 0xf is so we dont write similar TLB entries
42
* in the same 4-way entry group. details...
45
local_irq_save(flags);
46
for(i = 0; i < NUM_TLB_ENTRIES; i++) {
47
*R_TLB_SELECT = ( IO_FIELD(R_TLB_SELECT, index, i) );
48
*R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
49
IO_FIELD(R_TLB_HI, vpn, i & 0xf ) );
51
*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no ) |
52
IO_STATE(R_TLB_LO, valid, no ) |
53
IO_STATE(R_TLB_LO, kernel,no ) |
54
IO_STATE(R_TLB_LO, we, no ) |
55
IO_FIELD(R_TLB_LO, pfn, 0 ) );
57
local_irq_restore(flags);
58
D(printk("tlb: flushed all\n"));
61
/* invalidate the selected mm context only */
64
flush_tlb_mm(struct mm_struct *mm)
67
int page_id = mm->context.page_id;
70
D(printk("tlb: flush mm context %d (%p)\n", page_id, mm));
72
if(page_id == NO_CONTEXT)
75
/* mark the TLB entries that match the page_id as invalid.
76
* here we could also check the _PAGE_GLOBAL bit and NOT flush
77
* global pages. is it worth the extra I/O ?
80
local_irq_save(flags);
81
for(i = 0; i < NUM_TLB_ENTRIES; i++) {
82
*R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i);
83
if (IO_EXTRACT(R_TLB_HI, page_id, *R_TLB_HI) == page_id) {
84
*R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
85
IO_FIELD(R_TLB_HI, vpn, i & 0xf ) );
87
*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no ) |
88
IO_STATE(R_TLB_LO, valid, no ) |
89
IO_STATE(R_TLB_LO, kernel,no ) |
90
IO_STATE(R_TLB_LO, we, no ) |
91
IO_FIELD(R_TLB_LO, pfn, 0 ) );
94
local_irq_restore(flags);
97
/* invalidate a single page */
99
void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
101
struct mm_struct *mm = vma->vm_mm;
102
int page_id = mm->context.page_id;
106
D(printk("tlb: flush page %p in context %d (%p)\n", addr, page_id, mm));
108
if(page_id == NO_CONTEXT)
111
addr &= PAGE_MASK; /* perhaps not necessary */
113
/* invalidate those TLB entries that match both the mm context
114
* and the virtual address requested
117
local_irq_save(flags);
118
for(i = 0; i < NUM_TLB_ENTRIES; i++) {
119
unsigned long tlb_hi;
120
*R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i);
122
if (IO_EXTRACT(R_TLB_HI, page_id, tlb_hi) == page_id &&
123
(tlb_hi & PAGE_MASK) == addr) {
124
*R_TLB_HI = IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
125
addr; /* same addr as before works. */
127
*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no ) |
128
IO_STATE(R_TLB_LO, valid, no ) |
129
IO_STATE(R_TLB_LO, kernel,no ) |
130
IO_STATE(R_TLB_LO, we, no ) |
131
IO_FIELD(R_TLB_LO, pfn, 0 ) );
134
local_irq_restore(flags);
138
* Initialize the context related info for a new mm_struct
143
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
145
mm->context.page_id = NO_CONTEXT;
149
/* called in schedule() just before actually doing the switch_to */
151
void switch_mm(struct mm_struct *prev, struct mm_struct *next,
152
struct task_struct *tsk)
155
/* make sure we have a context */
156
get_mmu_context(next);
158
/* remember the pgd for the fault handlers
159
* this is similar to the pgd register in some other CPU's.
160
* we need our own copy of it because current and active_mm
161
* might be invalid at points where we still need to derefer
165
per_cpu(current_pgd, smp_processor_id()) = next->pgd;
167
/* switch context in the MMU */
169
D(printk(KERN_DEBUG "switching mmu_context to %d (%p)\n",
170
next->context, next));
172
*R_MMU_CONTEXT = IO_FIELD(R_MMU_CONTEXT,
173
page_id, next->context.page_id);