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Chris Zankel9a8fd552005-06-23 22:01:26 -07001/*
2 * include/asm-xtensa/mmu_context.h
3 *
4 * Switch an MMU context.
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 * Copyright (C) 2001 - 2005 Tensilica Inc.
11 */
12
13#ifndef _XTENSA_MMU_CONTEXT_H
14#define _XTENSA_MMU_CONTEXT_H
15
Chris Zankel9a8fd552005-06-23 22:01:26 -070016#include <linux/stringify.h>
Chris Zankelde4f6e52007-05-31 17:47:01 -070017#include <linux/sched.h>
Chris Zankel9a8fd552005-06-23 22:01:26 -070018
19#include <asm/pgtable.h>
Chris Zankel9a8fd552005-06-23 22:01:26 -070020#include <asm/cacheflush.h>
21#include <asm/tlbflush.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020022#include <asm-generic/mm_hooks.h>
Chris Zankel9a8fd552005-06-23 22:01:26 -070023
Chris Zankel173d6682006-12-10 02:18:48 -080024#define XCHAL_MMU_ASID_BITS 8
Chris Zankel9a8fd552005-06-23 22:01:26 -070025
26#if (XCHAL_HAVE_TLBS != 1)
27# error "Linux must have an MMU!"
28#endif
29
Chris Zankel9a8fd552005-06-23 22:01:26 -070030extern unsigned long asid_cache;
Chris Zankel9a8fd552005-06-23 22:01:26 -070031
32/*
33 * NO_CONTEXT is the invalid ASID value that we don't ever assign to
Chris Zankel173d6682006-12-10 02:18:48 -080034 * any user or kernel context.
35 *
36 * 0 invalid
37 * 1 kernel
38 * 2 reserved
39 * 3 reserved
40 * 4...255 available
Chris Zankel9a8fd552005-06-23 22:01:26 -070041 */
42
Chris Zankel173d6682006-12-10 02:18:48 -080043#define NO_CONTEXT 0
44#define ASID_USER_FIRST 4
45#define ASID_MASK ((1 << XCHAL_MMU_ASID_BITS) - 1)
46#define ASID_INSERT(x) (0x03020001 | (((x) & ASID_MASK) << 8))
Chris Zankel9a8fd552005-06-23 22:01:26 -070047
Adrian Bunkd99cf712005-09-03 15:57:53 -070048static inline void set_rasid_register (unsigned long val)
Chris Zankel9a8fd552005-06-23 22:01:26 -070049{
50 __asm__ __volatile__ (" wsr %0, "__stringify(RASID)"\n\t"
51 " isync\n" : : "a" (val));
52}
53
Adrian Bunkd99cf712005-09-03 15:57:53 -070054static inline unsigned long get_rasid_register (void)
Chris Zankel9a8fd552005-06-23 22:01:26 -070055{
56 unsigned long tmp;
Chris Zankel173d6682006-12-10 02:18:48 -080057 __asm__ __volatile__ (" rsr %0,"__stringify(RASID)"\n\t" : "=a" (tmp));
Chris Zankel9a8fd552005-06-23 22:01:26 -070058 return tmp;
59}
60
Adrian Bunkd99cf712005-09-03 15:57:53 -070061static inline void
Chris Zankel173d6682006-12-10 02:18:48 -080062__get_new_mmu_context(struct mm_struct *mm)
Chris Zankel9a8fd552005-06-23 22:01:26 -070063{
64 extern void flush_tlb_all(void);
Chris Zankel173d6682006-12-10 02:18:48 -080065 if (! (++asid_cache & ASID_MASK) ) {
Chris Zankel9a8fd552005-06-23 22:01:26 -070066 flush_tlb_all(); /* start new asid cycle */
Chris Zankel173d6682006-12-10 02:18:48 -080067 asid_cache += ASID_USER_FIRST;
Chris Zankel9a8fd552005-06-23 22:01:26 -070068 }
Chris Zankel173d6682006-12-10 02:18:48 -080069 mm->context = asid_cache;
Chris Zankel9a8fd552005-06-23 22:01:26 -070070}
71
Adrian Bunkd99cf712005-09-03 15:57:53 -070072static inline void
Chris Zankel173d6682006-12-10 02:18:48 -080073__load_mmu_context(struct mm_struct *mm)
Chris Zankel9a8fd552005-06-23 22:01:26 -070074{
Chris Zankel173d6682006-12-10 02:18:48 -080075 set_rasid_register(ASID_INSERT(mm->context));
76 invalidate_page_directory();
Chris Zankel9a8fd552005-06-23 22:01:26 -070077}
78
Chris Zankel9a8fd552005-06-23 22:01:26 -070079/*
80 * Initialize the context related info for a new mm_struct
81 * instance.
82 */
83
Adrian Bunkd99cf712005-09-03 15:57:53 -070084static inline int
Chris Zankel9a8fd552005-06-23 22:01:26 -070085init_new_context(struct task_struct *tsk, struct mm_struct *mm)
86{
87 mm->context = NO_CONTEXT;
88 return 0;
89}
90
Chris Zankel173d6682006-12-10 02:18:48 -080091/*
92 * After we have set current->mm to a new value, this activates
93 * the context for the new mm so we see the new mappings.
94 */
95static inline void
96activate_mm(struct mm_struct *prev, struct mm_struct *next)
97{
98 /* Unconditionally get a new ASID. */
99
100 __get_new_mmu_context(next);
101 __load_mmu_context(next);
102}
103
104
Adrian Bunkd99cf712005-09-03 15:57:53 -0700105static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
Chris Zankel9a8fd552005-06-23 22:01:26 -0700106 struct task_struct *tsk)
107{
108 unsigned long asid = asid_cache;
109
110 /* Check if our ASID is of an older version and thus invalid */
111
Chris Zankel173d6682006-12-10 02:18:48 -0800112 if (next->context == NO_CONTEXT || ((next->context^asid) & ~ASID_MASK))
113 __get_new_mmu_context(next);
Chris Zankel9a8fd552005-06-23 22:01:26 -0700114
Chris Zankel173d6682006-12-10 02:18:48 -0800115 __load_mmu_context(next);
Chris Zankel9a8fd552005-06-23 22:01:26 -0700116}
117
118#define deactivate_mm(tsk, mm) do { } while(0)
119
120/*
121 * Destroy context related info for an mm_struct that is about
122 * to be put to rest.
123 */
Adrian Bunkd99cf712005-09-03 15:57:53 -0700124static inline void destroy_context(struct mm_struct *mm)
Chris Zankel9a8fd552005-06-23 22:01:26 -0700125{
Chris Zankel9a8fd552005-06-23 22:01:26 -0700126 invalidate_page_directory();
127}
128
129
130static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
131{
132 /* Nothing to do. */
133
134}
135
136#endif /* _XTENSA_MMU_CONTEXT_H */