arch/mips/include/asm/mmu_context.h

   1 /*
   2  * Switch a MMU context.
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 1996, 1997, 1998, 1999 by Ralf Baechle
   9  * Copyright (C) 1999 Silicon Graphics, Inc.
  10  */
  11 #ifndef _ASM_MMU_CONTEXT_H
  12 #define _ASM_MMU_CONTEXT_H
  13
  14 #include <linux/errno.h>
  15 #include <linux/sched.h>
  16 #include <linux/smp.h>
  17 #include <linux/slab.h>
  18 #include <asm/cacheflush.h>
  19 #include <asm/hazards.h>
  20 #include <asm/tlbflush.h>
  21 #include <asm-generic/mm_hooks.h>
  22
  23 #define htw_set_pwbase(pgd)                                             \
  24 do {                                                                    \
  25         if (cpu_has_htw) {                                              \
  26                 write_c0_pwbase(pgd);                                   \
  27                 back_to_back_c0_hazard();                               \
  28                 htw_reset();                                            \
  29         }                                                               \
  30 } while (0)
  31
  32 #define TLBMISS_HANDLER_SETUP_PGD(pgd)                                  \
  33 do {                                                                    \
  34         extern void tlbmiss_handler_setup_pgd(unsigned long);           \
  35         tlbmiss_handler_setup_pgd((unsigned long)(pgd));                \
  36         htw_set_pwbase((unsigned long)pgd);                             \
  37 } while (0)
  38
  39 #ifdef CONFIG_MIPS_PGD_C0_CONTEXT
  40
  41 #define TLBMISS_HANDLER_RESTORE()                                       \
  42         write_c0_xcontext((unsigned long) smp_processor_id() <<         \
  43                           SMP_CPUID_REGSHIFT)
  44
  45 #define TLBMISS_HANDLER_SETUP()                                         \
  46         do {                                                            \
  47                 TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir);              \
  48                 TLBMISS_HANDLER_RESTORE();                              \
  49         } while (0)
  50
  51 #else /* !CONFIG_MIPS_PGD_C0_CONTEXT: using  pgd_current*/
  52
  53 /*
  54  * For the fast tlb miss handlers, we keep a per cpu array of pointers
  55  * to the current pgd for each processor. Also, the proc. id is stuffed
  56  * into the context register.
  57  */
  58 extern unsigned long pgd_current[];
  59
  60 #define TLBMISS_HANDLER_RESTORE()                                       \
  61         write_c0_context((unsigned long) smp_processor_id() <<          \
  62                          SMP_CPUID_REGSHIFT)
  63
  64 #define TLBMISS_HANDLER_SETUP()                                         \
  65         TLBMISS_HANDLER_RESTORE();                                      \
  66         back_to_back_c0_hazard();                                       \
  67         TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
  68 #endif /* CONFIG_MIPS_PGD_C0_CONTEXT*/
  69 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
  70
  71 #define ASID_INC        0x40
  72 #define ASID_MASK       0xfc0
  73
  74 #elif defined(CONFIG_CPU_R8000)
  75
  76 #define ASID_INC        0x10
  77 #define ASID_MASK       0xff0
  78
  79 #else /* FIXME: not correct for R6000 */
  80
  81 #define ASID_INC        0x1
  82 #define ASID_MASK       0xff
  83
  84 #endif
  85
  86 #define cpu_context(cpu, mm)    ((mm)->context.asid[cpu])
  87 #define cpu_asid(cpu, mm)       (cpu_context((cpu), (mm)) & ASID_MASK)
  88 #define asid_cache(cpu)         (cpu_data[cpu].asid_cache)
  89
  90 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  91 {
  92 }
  93
  94 /*
  95  *  All unused by hardware upper bits will be considered
  96  *  as a software asid extension.
  97  */
  98 #define ASID_VERSION_MASK  ((unsigned long)~(ASID_MASK|(ASID_MASK-1)))
  99 #define ASID_FIRST_VERSION ((unsigned long)(~ASID_VERSION_MASK) + 1)
 100
 101 /* Normal, classic MIPS get_new_mmu_context */
 102 static inline void
 103 get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
 104 {
 105         extern void kvm_local_flush_tlb_all(void);
 106         unsigned long asid = asid_cache(cpu);
 107
 108         if (! ((asid += ASID_INC) & ASID_MASK) ) {
 109                 if (cpu_has_vtag_icache)
 110                         flush_icache_all();
 111 #ifdef CONFIG_KVM
 112                 kvm_local_flush_tlb_all();      /* start new asid cycle */
 113 #else
 114                 local_flush_tlb_all();  /* start new asid cycle */
 115 #endif
 116                 if (!asid)              /* fix version if needed */
 117                         asid = ASID_FIRST_VERSION;
 118         }
 119
 120         cpu_context(cpu, mm) = asid_cache(cpu) = asid;
 121 }
 122
 123 /*
 124  * Initialize the context related info for a new mm_struct
 125  * instance.
 126  */
 127 static inline int
 128 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 129 {
 130         int i;
 131
 132         for_each_possible_cpu(i)
 133                 cpu_context(i, mm) = 0;
 134
 135         return 0;
 136 }
 137
 138 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 139                              struct task_struct *tsk)
 140 {
 141         unsigned int cpu = smp_processor_id();
 142         unsigned long flags;
 143         local_irq_save(flags);
 144
 145         /* Check if our ASID is of an older version and thus invalid */
 146         if ((cpu_context(cpu, next) ^ asid_cache(cpu)) & ASID_VERSION_MASK)
 147                 get_new_mmu_context(next, cpu);
 148         write_c0_entryhi(cpu_asid(cpu, next));
 149         TLBMISS_HANDLER_SETUP_PGD(next->pgd);
 150
 151         /*
 152          * Mark current->active_mm as not "active" anymore.
 153          * We don't want to mislead possible IPI tlb flush routines.
 154          */
 155         cpumask_clear_cpu(cpu, mm_cpumask(prev));
 156         cpumask_set_cpu(cpu, mm_cpumask(next));
 157
 158         local_irq_restore(flags);
 159 }
 160
 161 /*
 162  * Destroy context related info for an mm_struct that is about
 163  * to be put to rest.
 164  */
 165 static inline void destroy_context(struct mm_struct *mm)
 166 {
 167 }
 168
 169 #define deactivate_mm(tsk, mm)  do { } while (0)
 170
 171 /*
 172  * After we have set current->mm to a new value, this activates
 173  * the context for the new mm so we see the new mappings.
 174  */
 175 static inline void
 176 activate_mm(struct mm_struct *prev, struct mm_struct *next)
 177 {
 178         unsigned long flags;
 179         unsigned int cpu = smp_processor_id();
 180
 181         local_irq_save(flags);
 182
 183         /* Unconditionally get a new ASID.  */
 184         get_new_mmu_context(next, cpu);
 185
 186         write_c0_entryhi(cpu_asid(cpu, next));
 187         TLBMISS_HANDLER_SETUP_PGD(next->pgd);
 188
 189         /* mark mmu ownership change */
 190         cpumask_clear_cpu(cpu, mm_cpumask(prev));
 191         cpumask_set_cpu(cpu, mm_cpumask(next));
 192
 193         local_irq_restore(flags);
 194 }
 195
 196 /*
 197  * If mm is currently active_mm, we can't really drop it.  Instead,
 198  * we will get a new one for it.
 199  */
 200 static inline void
 201 drop_mmu_context(struct mm_struct *mm, unsigned cpu)
 202 {
 203         unsigned long flags;
 204
 205         local_irq_save(flags);
 206
 207         if (cpumask_test_cpu(cpu, mm_cpumask(mm)))  {
 208                 get_new_mmu_context(mm, cpu);
 209                 write_c0_entryhi(cpu_asid(cpu, mm));
 210         } else {
 211                 /* will get a new context next time */
 212                 cpu_context(cpu, mm) = 0;
 213         }
 214         local_irq_restore(flags);
 215 }
 216
 217 #endif /* _ASM_MMU_CONTEXT_H */