include/asm-sh64/mmu_context.h

   1 #ifndef __ASM_SH64_MMU_CONTEXT_H
   2 #define __ASM_SH64_MMU_CONTEXT_H
   3
   4 /*
   5  * This file is subject to the terms and conditions of the GNU General Public
   6  * License.  See the file "COPYING" in the main directory of this archive
   7  * for more details.
   8  *
   9  * include/asm-sh64/mmu_context.h
  10  *
  11  * Copyright (C) 2000, 2001  Paolo Alberelli
  12  * Copyright (C) 2003  Paul Mundt
  13  *
  14  * ASID handling idea taken from MIPS implementation.
  15  *
  16  */
  17
  18 #ifndef __ASSEMBLY__
  19
  20 /*
  21  * Cache of MMU context last used.
  22  *
  23  * The MMU "context" consists of two things:
  24  *   (a) TLB cache version (or cycle, top 24 bits of mmu_context_cache)
  25  *   (b) ASID (Address Space IDentifier, bottom 8 bits of mmu_context_cache)
  26  */
  27 extern unsigned long mmu_context_cache;
  28
  29 #include <linux/config.h>
  30 #include <asm/page.h>
  31
  32
  33 /* Current mm's pgd */
  34 extern pgd_t *mmu_pdtp_cache;
  35
  36 #define SR_ASID_MASK            0xffffffffff00ffffULL
  37 #define SR_ASID_SHIFT           16
  38
  39 #define MMU_CONTEXT_ASID_MASK           0x000000ff
  40 #define MMU_CONTEXT_VERSION_MASK        0xffffff00
  41 #define MMU_CONTEXT_FIRST_VERSION       0x00000100
  42 #define NO_CONTEXT                      0
  43
  44 /* ASID is 8-bit value, so it can't be 0x100 */
  45 #define MMU_NO_ASID                     0x100
  46
  47
  48 /*
  49  * Virtual Page Number mask
  50  */
  51 #define MMU_VPN_MASK    0xfffff000
  52
  53 static inline void
  54 get_new_mmu_context(struct mm_struct *mm)
  55 {
  56         extern void flush_tlb_all(void);
  57         extern void flush_cache_all(void);
  58
  59         unsigned long mc = ++mmu_context_cache;
  60
  61         if (!(mc & MMU_CONTEXT_ASID_MASK)) {
  62                 /* We exhaust ASID of this version.
  63                    Flush all TLB and start new cycle. */
  64                 flush_tlb_all();
  65                 /* We have to flush all caches as ASIDs are
  66                    used in cache */
  67                 flush_cache_all();
  68                 /* Fix version if needed.
  69                    Note that we avoid version #0/asid #0 to distingush NO_CONTEXT. */
  70                 if (!mc)
  71                         mmu_context_cache = mc = MMU_CONTEXT_FIRST_VERSION;
  72         }
  73         mm->context = mc;
  74 }
  75
  76 /*
  77  * Get MMU context if needed.
  78  */
  79 static __inline__ void
  80 get_mmu_context(struct mm_struct *mm)
  81 {
  82         if (mm) {
  83                 unsigned long mc = mmu_context_cache;
  84                 /* Check if we have old version of context.
  85                    If it's old, we need to get new context with new version. */
  86                 if ((mm->context ^ mc) & MMU_CONTEXT_VERSION_MASK)
  87                         get_new_mmu_context(mm);
  88         }
  89 }
  90
  91 /*
  92  * Initialize the context related info for a new mm_struct
  93  * instance.
  94  */
  95 static inline int init_new_context(struct task_struct *tsk,
  96                                         struct mm_struct *mm)
  97 {
  98         mm->context = NO_CONTEXT;
  99
 100         return 0;
 101 }
 102
 103 /*
 104  * Destroy context related info for an mm_struct that is about
 105  * to be put to rest.
 106  */
 107 static inline void destroy_context(struct mm_struct *mm)
 108 {
 109         extern void flush_tlb_mm(struct mm_struct *mm);
 110
 111         /* Well, at least free TLB entries */
 112         flush_tlb_mm(mm);
 113 }
 114
 115 #endif  /* __ASSEMBLY__ */
 116
 117 /* Common defines */
 118 #define TLB_STEP        0x00000010
 119 #define TLB_PTEH        0x00000000
 120 #define TLB_PTEL        0x00000008
 121
 122 /* PTEH defines */
 123 #define PTEH_ASID_SHIFT 2
 124 #define PTEH_VALID      0x0000000000000001
 125 #define PTEH_SHARED     0x0000000000000002
 126 #define PTEH_MATCH_ASID 0x00000000000003ff
 127
 128 #ifndef __ASSEMBLY__
 129 /* This has to be a common function because the next location to fill
 130  * information is shared. */
 131 extern void __do_tlb_refill(unsigned long address, unsigned long long is_text_not_data, pte_t *pte);
 132
 133 /* Profiling counter. */
 134 #ifdef CONFIG_SH64_PROC_TLB
 135 extern unsigned long long calls_to_do_fast_page_fault;
 136 #endif
 137
 138 static inline unsigned long get_asid(void)
 139 {
 140         unsigned long long sr;
 141
 142         asm volatile ("getcon   " __SR ", %0\n\t"
 143                       : "=r" (sr));
 144
 145         sr = (sr >> SR_ASID_SHIFT) & MMU_CONTEXT_ASID_MASK;
 146         return (unsigned long) sr;
 147 }
 148
 149 /* Set ASID into SR */
 150 static inline void set_asid(unsigned long asid)
 151 {
 152         unsigned long long sr, pc;
 153
 154         asm volatile ("getcon   " __SR ", %0" : "=r" (sr));
 155
 156         sr = (sr & SR_ASID_MASK) | (asid << SR_ASID_SHIFT);
 157
 158         /*
 159          * It is possible that this function may be inlined and so to avoid
 160          * the assembler reporting duplicate symbols we make use of the gas trick
 161          * of generating symbols using numerics and forward reference.
 162          */
 163         asm volatile ("movi     1, %1\n\t"
 164                       "shlli    %1, 28, %1\n\t"
 165                       "or       %0, %1, %1\n\t"
 166                       "putcon   %1, " __SR "\n\t"
 167                       "putcon   %0, " __SSR "\n\t"
 168                       "movi     1f, %1\n\t"
 169                       "ori      %1, 1 , %1\n\t"
 170                       "putcon   %1, " __SPC "\n\t"
 171                       "rte\n"
 172                       "1:\n\t"
 173                       : "=r" (sr), "=r" (pc) : "0" (sr));
 174 }
 175
 176 /*
 177  * After we have set current->mm to a new value, this activates
 178  * the context for the new mm so we see the new mappings.
 179  */
 180 static __inline__ void activate_context(struct mm_struct *mm)
 181 {
 182         get_mmu_context(mm);
 183         set_asid(mm->context & MMU_CONTEXT_ASID_MASK);
 184 }
 185
 186
 187 static __inline__ void switch_mm(struct mm_struct *prev,
 188                                  struct mm_struct *next,
 189                                  struct task_struct *tsk)
 190 {
 191         if (prev != next) {
 192                 mmu_pdtp_cache = next->pgd;
 193                 activate_context(next);
 194         }
 195 }
 196
 197 #define deactivate_mm(tsk,mm)   do { } while (0)
 198
 199 #define activate_mm(prev, next) \
 200         switch_mm((prev),(next),NULL)
 201
 202 static inline void
 203 enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 204 {
 205 }
 206
 207 #endif  /* __ASSEMBLY__ */
 208
 209 #endif /* __ASM_SH64_MMU_CONTEXT_H */