include/asm-sh/mmu_context.h

   1 /*
   2  * Copyright (C) 1999 Niibe Yutaka
   3  * Copyright (C) 2003 - 2006 Paul Mundt
   4  *
   5  * ASID handling idea taken from MIPS implementation.
   6  */
   7 #ifndef __ASM_SH_MMU_CONTEXT_H
   8 #define __ASM_SH_MMU_CONTEXT_H
   9 #ifdef __KERNEL__
  10
  11 #include <asm/cpu/mmu_context.h>
  12 #include <asm/tlbflush.h>
  13 #include <asm/uaccess.h>
  14 #include <asm/io.h>
  15 #include <asm-generic/mm_hooks.h>
  16
  17 /*
  18  * The MMU "context" consists of two things:
  19  *    (a) TLB cache version (or round, cycle whatever expression you like)
  20  *    (b) ASID (Address Space IDentifier)
  21  */
  22
  23 #define MMU_CONTEXT_ASID_MASK           0x000000ff
  24 #define MMU_CONTEXT_VERSION_MASK        0xffffff00
  25 #define MMU_CONTEXT_FIRST_VERSION       0x00000100
  26 #define NO_CONTEXT                      0
  27
  28 /* ASID is 8-bit value, so it can't be 0x100 */
  29 #define MMU_NO_ASID                     0x100
  30
  31 #define cpu_context(cpu, mm)    ((mm)->context.id[cpu])
  32 #define cpu_asid(cpu, mm)       (cpu_context((cpu), (mm)) & \
  33                                  MMU_CONTEXT_ASID_MASK)
  34 #define asid_cache(cpu)         (cpu_data[cpu].asid_cache)
  35
  36 /*
  37  * Virtual Page Number mask
  38  */
  39 #define MMU_VPN_MASK    0xfffff000
  40
  41 #ifdef CONFIG_MMU
  42 /*
  43  * Get MMU context if needed.
  44  */
  45 static inline void get_mmu_context(struct mm_struct *mm, unsigned int cpu)
  46 {
  47         unsigned long asid = asid_cache(cpu);
  48
  49         /* Check if we have old version of context. */
  50         if (((cpu_context(cpu, mm) ^ asid) & MMU_CONTEXT_VERSION_MASK) == 0)
  51                 /* It's up to date, do nothing */
  52                 return;
  53
  54         /* It's old, we need to get new context with new version. */
  55         if (!(++asid & MMU_CONTEXT_ASID_MASK)) {
  56                 /*
  57                  * We exhaust ASID of this version.
  58                  * Flush all TLB and start new cycle.
  59                  */
  60                 flush_tlb_all();
  61
  62                 /*
  63                  * Fix version; Note that we avoid version #0
  64                  * to distingush NO_CONTEXT.
  65                  */
  66                 if (!asid)
  67                         asid = MMU_CONTEXT_FIRST_VERSION;
  68         }
  69
  70         cpu_context(cpu, mm) = asid_cache(cpu) = asid;
  71 }
  72
  73 /*
  74  * Initialize the context related info for a new mm_struct
  75  * instance.
  76  */
  77 static inline int init_new_context(struct task_struct *tsk,
  78                                    struct mm_struct *mm)
  79 {
  80         int i;
  81
  82         for (i = 0; i < num_online_cpus(); i++)
  83                 cpu_context(i, mm) = NO_CONTEXT;
  84
  85         return 0;
  86 }
  87
  88 /*
  89  * Destroy context related info for an mm_struct that is about
  90  * to be put to rest.
  91  */
  92 static inline void destroy_context(struct mm_struct *mm)
  93 {
  94         /* Do nothing */
  95 }
  96
  97 static inline void set_asid(unsigned long asid)
  98 {
  99         unsigned long __dummy;
 100
 101         __asm__ __volatile__ ("mov.l    %2, %0\n\t"
 102                               "and      %3, %0\n\t"
 103                               "or       %1, %0\n\t"
 104                               "mov.l    %0, %2"
 105                               : "=&r" (__dummy)
 106                               : "r" (asid), "m" (__m(MMU_PTEH)),
 107                                 "r" (0xffffff00));
 108 }
 109
 110 static inline unsigned long get_asid(void)
 111 {
 112         unsigned long asid;
 113
 114         __asm__ __volatile__ ("mov.l    %1, %0"
 115                               : "=r" (asid)
 116                               : "m" (__m(MMU_PTEH)));
 117         asid &= MMU_CONTEXT_ASID_MASK;
 118         return asid;
 119 }
 120
 121 /*
 122  * After we have set current->mm to a new value, this activates
 123  * the context for the new mm so we see the new mappings.
 124  */
 125 static inline void activate_context(struct mm_struct *mm, unsigned int cpu)
 126 {
 127         get_mmu_context(mm, cpu);
 128         set_asid(cpu_asid(cpu, mm));
 129 }
 130
 131 /* MMU_TTB is used for optimizing the fault handling. */
 132 static inline void set_TTB(pgd_t *pgd)
 133 {
 134         ctrl_outl((unsigned long)pgd, MMU_TTB);
 135 }
 136
 137 static inline pgd_t *get_TTB(void)
 138 {
 139         return (pgd_t *)ctrl_inl(MMU_TTB);
 140 }
 141
 142 static inline void switch_mm(struct mm_struct *prev,
 143                              struct mm_struct *next,
 144                              struct task_struct *tsk)
 145 {
 146         unsigned int cpu = smp_processor_id();
 147
 148         if (likely(prev != next)) {
 149                 cpu_set(cpu, next->cpu_vm_mask);
 150                 set_TTB(next->pgd);
 151                 activate_context(next, cpu);
 152         } else
 153                 if (!cpu_test_and_set(cpu, next->cpu_vm_mask))
 154                         activate_context(next, cpu);
 155 }
 156
 157 #define deactivate_mm(tsk,mm)   do { } while (0)
 158
 159 #define activate_mm(prev, next) \
 160         switch_mm((prev),(next),NULL)
 161
 162 static inline void
 163 enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 164 {
 165 }
 166 #else /* !CONFIG_MMU */
 167 #define get_mmu_context(mm)             do { } while (0)
 168 #define init_new_context(tsk,mm)        (0)
 169 #define destroy_context(mm)             do { } while (0)
 170 #define set_asid(asid)                  do { } while (0)
 171 #define get_asid()                      (0)
 172 #define set_TTB(pgd)                    do { } while (0)
 173 #define get_TTB()                       (0)
 174 #define activate_context(mm,cpu)        do { } while (0)
 175 #define switch_mm(prev,next,tsk)        do { } while (0)
 176 #define deactivate_mm(tsk,mm)           do { } while (0)
 177 #define activate_mm(prev,next)          do { } while (0)
 178 #define enter_lazy_tlb(mm,tsk)          do { } while (0)
 179 #endif /* CONFIG_MMU */
 180
 181 #if defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH4)
 182 /*
 183  * If this processor has an MMU, we need methods to turn it off/on ..
 184  * paging_init() will also have to be updated for the processor in
 185  * question.
 186  */
 187 static inline void enable_mmu(void)
 188 {
 189         unsigned int cpu = smp_processor_id();
 190
 191         /* Enable MMU */
 192         ctrl_outl(MMU_CONTROL_INIT, MMUCR);
 193         ctrl_barrier();
 194
 195         if (asid_cache(cpu) == NO_CONTEXT)
 196                 asid_cache(cpu) = MMU_CONTEXT_FIRST_VERSION;
 197
 198         set_asid(asid_cache(cpu) & MMU_CONTEXT_ASID_MASK);
 199 }
 200
 201 static inline void disable_mmu(void)
 202 {
 203         unsigned long cr;
 204
 205         cr = ctrl_inl(MMUCR);
 206         cr &= ~MMU_CONTROL_INIT;
 207         ctrl_outl(cr, MMUCR);
 208
 209         ctrl_barrier();
 210 }
 211 #else
 212 /*
 213  * MMU control handlers for processors lacking memory
 214  * management hardware.
 215  */
 216 #define enable_mmu()    do { } while (0)
 217 #define disable_mmu()   do { } while (0)
 218 #endif
 219
 220 #endif /* __KERNEL__ */
 221 #endif /* __ASM_SH_MMU_CONTEXT_H */