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-rw-r--r--arch/microblaze/include/asm/mmu_context.h26
-rw-r--r--arch/microblaze/include/asm/mmu_context_mm.h140
-rw-r--r--arch/microblaze/include/asm/mmu_context_no.h23
-rw-r--r--arch/microblaze/mm/mmu_context.c70
4 files changed, 238 insertions, 21 deletions
diff --git a/arch/microblaze/include/asm/mmu_context.h b/arch/microblaze/include/asm/mmu_context.h
index 150ca01b74ba..385fed16bbfb 100644
--- a/arch/microblaze/include/asm/mmu_context.h
+++ b/arch/microblaze/include/asm/mmu_context.h
@@ -1,21 +1,5 @@
1/* 1#ifdef CONFIG_MMU
2 * Copyright (C) 2006 Atmark Techno, Inc. 2# include "mmu_context_mm.h"
3 * 3#else
4 * This file is subject to the terms and conditions of the GNU General Public 4# include "mmu_context_no.h"
5 * License. See the file "COPYING" in the main directory of this archive 5#endif
6 * for more details.
7 */
8
9#ifndef _ASM_MICROBLAZE_MMU_CONTEXT_H
10#define _ASM_MICROBLAZE_MMU_CONTEXT_H
11
12# define init_new_context(tsk, mm) ({ 0; })
13
14# define enter_lazy_tlb(mm, tsk) do {} while (0)
15# define change_mm_context(old, ctx, _pml4) do {} while (0)
16# define destroy_context(mm) do {} while (0)
17# define deactivate_mm(tsk, mm) do {} while (0)
18# define switch_mm(prev, next, tsk) do {} while (0)
19# define activate_mm(prev, next) do {} while (0)
20
21#endif /* _ASM_MICROBLAZE_MMU_CONTEXT_H */
diff --git a/arch/microblaze/include/asm/mmu_context_mm.h b/arch/microblaze/include/asm/mmu_context_mm.h
new file mode 100644
index 000000000000..3e5c254e8d1c
--- /dev/null
+++ b/arch/microblaze/include/asm/mmu_context_mm.h
@@ -0,0 +1,140 @@
1/*
2 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
3 * Copyright (C) 2008-2009 PetaLogix
4 * Copyright (C) 2006 Atmark Techno, Inc.
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10
11#ifndef _ASM_MICROBLAZE_MMU_CONTEXT_H
12#define _ASM_MICROBLAZE_MMU_CONTEXT_H
13
14#include <asm/atomic.h>
15#include <asm/bitops.h>
16#include <asm/mmu.h>
17#include <asm-generic/mm_hooks.h>
18
19# ifdef __KERNEL__
20/*
21 * This function defines the mapping from contexts to VSIDs (virtual
22 * segment IDs). We use a skew on both the context and the high 4 bits
23 * of the 32-bit virtual address (the "effective segment ID") in order
24 * to spread out the entries in the MMU hash table.
25 */
26# define CTX_TO_VSID(ctx, va) (((ctx) * (897 * 16) + ((va) >> 28) * 0x111) \
27 & 0xffffff)
28
29/*
30 MicroBlaze has 256 contexts, so we can just rotate through these
31 as a way of "switching" contexts. If the TID of the TLB is zero,
32 the PID/TID comparison is disabled, so we can use a TID of zero
33 to represent all kernel pages as shared among all contexts.
34 */
35
36static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
37{
38}
39
40# define NO_CONTEXT 256
41# define LAST_CONTEXT 255
42# define FIRST_CONTEXT 1
43
44/*
45 * Set the current MMU context.
46 * This is done byloading up the segment registers for the user part of the
47 * address space.
48 *
49 * Since the PGD is immediately available, it is much faster to simply
50 * pass this along as a second parameter, which is required for 8xx and
51 * can be used for debugging on all processors (if you happen to have
52 * an Abatron).
53 */
54extern void set_context(mm_context_t context, pgd_t *pgd);
55
56/*
57 * Bitmap of contexts in use.
58 * The size of this bitmap is LAST_CONTEXT + 1 bits.
59 */
60extern unsigned long context_map[];
61
62/*
63 * This caches the next context number that we expect to be free.
64 * Its use is an optimization only, we can't rely on this context
65 * number to be free, but it usually will be.
66 */
67extern mm_context_t next_mmu_context;
68
69/*
70 * Since we don't have sufficient contexts to give one to every task
71 * that could be in the system, we need to be able to steal contexts.
72 * These variables support that.
73 */
74extern atomic_t nr_free_contexts;
75extern struct mm_struct *context_mm[LAST_CONTEXT+1];
76extern void steal_context(void);
77
78/*
79 * Get a new mmu context for the address space described by `mm'.
80 */
81static inline void get_mmu_context(struct mm_struct *mm)
82{
83 mm_context_t ctx;
84
85 if (mm->context != NO_CONTEXT)
86 return;
87 while (atomic_dec_if_positive(&nr_free_contexts) < 0)
88 steal_context();
89 ctx = next_mmu_context;
90 while (test_and_set_bit(ctx, context_map)) {
91 ctx = find_next_zero_bit(context_map, LAST_CONTEXT+1, ctx);
92 if (ctx > LAST_CONTEXT)
93 ctx = 0;
94 }
95 next_mmu_context = (ctx + 1) & LAST_CONTEXT;
96 mm->context = ctx;
97 context_mm[ctx] = mm;
98}
99
100/*
101 * Set up the context for a new address space.
102 */
103# define init_new_context(tsk, mm) (((mm)->context = NO_CONTEXT), 0)
104
105/*
106 * We're finished using the context for an address space.
107 */
108static inline void destroy_context(struct mm_struct *mm)
109{
110 if (mm->context != NO_CONTEXT) {
111 clear_bit(mm->context, context_map);
112 mm->context = NO_CONTEXT;
113 atomic_inc(&nr_free_contexts);
114 }
115}
116
117static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
118 struct task_struct *tsk)
119{
120 tsk->thread.pgdir = next->pgd;
121 get_mmu_context(next);
122 set_context(next->context, next->pgd);
123}
124
125/*
126 * After we have set current->mm to a new value, this activates
127 * the context for the new mm so we see the new mappings.
128 */
129static inline void activate_mm(struct mm_struct *active_mm,
130 struct mm_struct *mm)
131{
132 current->thread.pgdir = mm->pgd;
133 get_mmu_context(mm);
134 set_context(mm->context, mm->pgd);
135}
136
137extern void mmu_context_init(void);
138
139# endif /* __KERNEL__ */
140#endif /* _ASM_MICROBLAZE_MMU_CONTEXT_H */
diff --git a/arch/microblaze/include/asm/mmu_context_no.h b/arch/microblaze/include/asm/mmu_context_no.h
new file mode 100644
index 000000000000..ba5567190154
--- /dev/null
+++ b/arch/microblaze/include/asm/mmu_context_no.h
@@ -0,0 +1,23 @@
1/*
2 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
3 * Copyright (C) 2008-2009 PetaLogix
4 * Copyright (C) 2006 Atmark Techno, Inc.
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10
11#ifndef _ASM_MICROBLAZE_MMU_CONTEXT_H
12#define _ASM_MICROBLAZE_MMU_CONTEXT_H
13
14# define init_new_context(tsk, mm) ({ 0; })
15
16# define enter_lazy_tlb(mm, tsk) do {} while (0)
17# define change_mm_context(old, ctx, _pml4) do {} while (0)
18# define destroy_context(mm) do {} while (0)
19# define deactivate_mm(tsk, mm) do {} while (0)
20# define switch_mm(prev, next, tsk) do {} while (0)
21# define activate_mm(prev, next) do {} while (0)
22
23#endif /* _ASM_MICROBLAZE_MMU_CONTEXT_H */
diff --git a/arch/microblaze/mm/mmu_context.c b/arch/microblaze/mm/mmu_context.c
new file mode 100644
index 000000000000..26ff82f4fa8f
--- /dev/null
+++ b/arch/microblaze/mm/mmu_context.c
@@ -0,0 +1,70 @@
1/*
2 * This file contains the routines for handling the MMU.
3 *
4 * Copyright (C) 2007 Xilinx, Inc. All rights reserved.
5 *
6 * Derived from arch/ppc/mm/4xx_mmu.c:
7 * -- paulus
8 *
9 * Derived from arch/ppc/mm/init.c:
10 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
11 *
12 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
13 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
14 * Copyright (C) 1996 Paul Mackerras
15 * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
16 *
17 * Derived from "arch/i386/mm/init.c"
18 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
19 *
20 * This program is free software; you can redistribute it and/or
21 * modify it under the terms of the GNU General Public License
22 * as published by the Free Software Foundation; either version
23 * 2 of the License, or (at your option) any later version.
24 *
25 */
26
27#include <linux/mm.h>
28#include <linux/init.h>
29
30#include <asm/tlbflush.h>
31#include <asm/mmu_context.h>
32
33mm_context_t next_mmu_context;
34unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
35atomic_t nr_free_contexts;
36struct mm_struct *context_mm[LAST_CONTEXT+1];
37
38/*
39 * Initialize the context management stuff.
40 */
41void __init mmu_context_init(void)
42{
43 /*
44 * The use of context zero is reserved for the kernel.
45 * This code assumes FIRST_CONTEXT < 32.
46 */
47 context_map[0] = (1 << FIRST_CONTEXT) - 1;
48 next_mmu_context = FIRST_CONTEXT;
49 atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
50}
51
52/*
53 * Steal a context from a task that has one at the moment.
54 *
55 * This isn't an LRU system, it just frees up each context in
56 * turn (sort-of pseudo-random replacement :). This would be the
57 * place to implement an LRU scheme if anyone were motivated to do it.
58 */
59void steal_context(void)
60{
61 struct mm_struct *mm;
62
63 /* free up context `next_mmu_context' */
64 /* if we shouldn't free context 0, don't... */
65 if (next_mmu_context < FIRST_CONTEXT)
66 next_mmu_context = FIRST_CONTEXT;
67 mm = context_mm[next_mmu_context];
68 flush_tlb_mm(mm);
69 destroy_context(mm);
70}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-21 04:45:22 -0500