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