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/slab.h>
  17 #include <asm/cacheflush.h>
  18 #include <asm/tlbflush.h>
  19 #ifdef CONFIG_MIPS_MT_SMTC
  20 #include <asm/mipsmtregs.h>
  21 #include <asm/smtc.h>
  22 #endif /* SMTC */
  23 #include <asm-generic/mm_hooks.h>
  24
  25 /*
  26  * For the fast tlb miss handlers, we keep a per cpu array of pointers
  27  * to the current pgd for each processor. Also, the proc. id is stuffed
  28  * into the context register.
  29  */
  30 extern unsigned long pgd_current[];
  31
  32 #define TLBMISS_HANDLER_SETUP_PGD(pgd) \
  33         pgd_current[smp_processor_id()] = (unsigned long)(pgd)
  34
  35 #ifdef CONFIG_32BIT
  36 #define TLBMISS_HANDLER_SETUP()                                         \
  37         write_c0_context((unsigned long) smp_processor_id() << 25);     \
  38         TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
  39 #endif
  40 #ifdef CONFIG_64BIT
  41 #define TLBMISS_HANDLER_SETUP()                                         \
  42         write_c0_context((unsigned long) smp_processor_id() << 26);     \
  43         TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
  44 #endif
  45
  46 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
  47
  48 #define ASID_INC        0x40
  49 #define ASID_MASK       0xfc0
  50
  51 #elif defined(CONFIG_CPU_R8000)
  52
  53 #define ASID_INC        0x10
  54 #define ASID_MASK       0xff0
  55
  56 #elif defined(CONFIG_CPU_RM9000)
  57
  58 #define ASID_INC        0x1
  59 #define ASID_MASK       0xfff
  60
  61 /* SMTC/34K debug hack - but maybe we'll keep it */
  62 #elif defined(CONFIG_MIPS_MT_SMTC)
  63
  64 #define ASID_INC        0x1
  65 extern unsigned long smtc_asid_mask;
  66 #define ASID_MASK       (smtc_asid_mask)
  67 #define HW_ASID_MASK    0xff
  68 /* End SMTC/34K debug hack */
  69 #else /* FIXME: not correct for R6000 */
  70
  71 #define ASID_INC        0x1
  72 #define ASID_MASK       0xff
  73
  74 #endif
  75
  76 #define cpu_context(cpu, mm)    ((mm)->context[cpu])
  77 #define cpu_asid(cpu, mm)       (cpu_context((cpu), (mm)) & ASID_MASK)
  78 #define asid_cache(cpu)         (cpu_data[cpu].asid_cache)
  79
  80 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  81 {
  82 }
  83
  84 /*
  85  *  All unused by hardware upper bits will be considered
  86  *  as a software asid extension.
  87  */
  88 #define ASID_VERSION_MASK  ((unsigned long)~(ASID_MASK|(ASID_MASK-1)))
  89 #define ASID_FIRST_VERSION ((unsigned long)(~ASID_VERSION_MASK) + 1)
  90
  91 #ifndef CONFIG_MIPS_MT_SMTC
  92 /* Normal, classic MIPS get_new_mmu_context */
  93 static inline void
  94 get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
  95 {
  96         unsigned long asid = asid_cache(cpu);
  97
  98         if (! ((asid += ASID_INC) & ASID_MASK) ) {
  99                 if (cpu_has_vtag_icache)
 100                         flush_icache_all();
 101                 local_flush_tlb_all();  /* start new asid cycle */
 102                 if (!asid)              /* fix version if needed */
 103                         asid = ASID_FIRST_VERSION;
 104         }
 105         cpu_context(cpu, mm) = asid_cache(cpu) = asid;
 106 }
 107
 108 #else /* CONFIG_MIPS_MT_SMTC */
 109
 110 #define get_new_mmu_context(mm, cpu) smtc_get_new_mmu_context((mm), (cpu))
 111
 112 #endif /* CONFIG_MIPS_MT_SMTC */
 113
 114 /*
 115  * Initialize the context related info for a new mm_struct
 116  * instance.
 117  */
 118 static inline int
 119 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 120 {
 121         int i;
 122
 123         for_each_online_cpu(i)
 124                 cpu_context(i, mm) = 0;
 125
 126         return 0;
 127 }
 128
 129 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 130                              struct task_struct *tsk)
 131 {
 132         unsigned int cpu = smp_processor_id();
 133         unsigned long flags;
 134 #ifdef CONFIG_MIPS_MT_SMTC
 135         unsigned long oldasid;
 136         unsigned long mtflags;
 137         int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
 138         local_irq_save(flags);
 139         mtflags = dvpe();
 140 #else /* Not SMTC */
 141         local_irq_save(flags);
 142 #endif /* CONFIG_MIPS_MT_SMTC */
 143
 144         /* Check if our ASID is of an older version and thus invalid */
 145         if ((cpu_context(cpu, next) ^ asid_cache(cpu)) & ASID_VERSION_MASK)
 146                 get_new_mmu_context(next, cpu);
 147 #ifdef CONFIG_MIPS_MT_SMTC
 148         /*
 149          * If the EntryHi ASID being replaced happens to be
 150          * the value flagged at ASID recycling time as having
 151          * an extended life, clear the bit showing it being
 152          * in use by this "CPU", and if that's the last bit,
 153          * free up the ASID value for use and flush any old
 154          * instances of it from the TLB.
 155          */
 156         oldasid = (read_c0_entryhi() & ASID_MASK);
 157         if(smtc_live_asid[mytlb][oldasid]) {
 158                 smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
 159                 if(smtc_live_asid[mytlb][oldasid] == 0)
 160                         smtc_flush_tlb_asid(oldasid);
 161         }
 162         /*
 163          * Tread softly on EntryHi, and so long as we support
 164          * having ASID_MASK smaller than the hardware maximum,
 165          * make sure no "soft" bits become "hard"...
 166          */
 167         write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
 168                         | (cpu_context(cpu, next) & ASID_MASK));
 169         ehb(); /* Make sure it propagates to TCStatus */
 170         evpe(mtflags);
 171 #else
 172         write_c0_entryhi(cpu_context(cpu, next));
 173 #endif /* CONFIG_MIPS_MT_SMTC */
 174         TLBMISS_HANDLER_SETUP_PGD(next->pgd);
 175
 176         /*
 177          * Mark current->active_mm as not "active" anymore.
 178          * We don't want to mislead possible IPI tlb flush routines.
 179          */
 180         cpu_clear(cpu, prev->cpu_vm_mask);
 181         cpu_set(cpu, next->cpu_vm_mask);
 182
 183         local_irq_restore(flags);
 184 }
 185
 186 /*
 187  * Destroy context related info for an mm_struct that is about
 188  * to be put to rest.
 189  */
 190 static inline void destroy_context(struct mm_struct *mm)
 191 {
 192 }
 193
 194 #define deactivate_mm(tsk, mm)  do { } while (0)
 195
 196 /*
 197  * After we have set current->mm to a new value, this activates
 198  * the context for the new mm so we see the new mappings.
 199  */
 200 static inline void
 201 activate_mm(struct mm_struct *prev, struct mm_struct *next)
 202 {
 203         unsigned long flags;
 204         unsigned int cpu = smp_processor_id();
 205
 206 #ifdef CONFIG_MIPS_MT_SMTC
 207         unsigned long oldasid;
 208         unsigned long mtflags;
 209         int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
 210 #endif /* CONFIG_MIPS_MT_SMTC */
 211
 212         local_irq_save(flags);
 213
 214         /* Unconditionally get a new ASID.  */
 215         get_new_mmu_context(next, cpu);
 216
 217 #ifdef CONFIG_MIPS_MT_SMTC
 218         /* See comments for similar code above */
 219         mtflags = dvpe();
 220         oldasid = read_c0_entryhi() & ASID_MASK;
 221         if(smtc_live_asid[mytlb][oldasid]) {
 222                 smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
 223                 if(smtc_live_asid[mytlb][oldasid] == 0)
 224                          smtc_flush_tlb_asid(oldasid);
 225         }
 226         /* See comments for similar code above */
 227         write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) |
 228                          (cpu_context(cpu, next) & ASID_MASK));
 229         ehb(); /* Make sure it propagates to TCStatus */
 230         evpe(mtflags);
 231 #else
 232         write_c0_entryhi(cpu_context(cpu, next));
 233 #endif /* CONFIG_MIPS_MT_SMTC */
 234         TLBMISS_HANDLER_SETUP_PGD(next->pgd);
 235
 236         /* mark mmu ownership change */
 237         cpu_clear(cpu, prev->cpu_vm_mask);
 238         cpu_set(cpu, next->cpu_vm_mask);
 239
 240         local_irq_restore(flags);
 241 }
 242
 243 /*
 244  * If mm is currently active_mm, we can't really drop it.  Instead,
 245  * we will get a new one for it.
 246  */
 247 static inline void
 248 drop_mmu_context(struct mm_struct *mm, unsigned cpu)
 249 {
 250         unsigned long flags;
 251 #ifdef CONFIG_MIPS_MT_SMTC
 252         unsigned long oldasid;
 253         /* Can't use spinlock because called from TLB flush within DVPE */
 254         unsigned int prevvpe;
 255         int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
 256 #endif /* CONFIG_MIPS_MT_SMTC */
 257
 258         local_irq_save(flags);
 259
 260         if (cpu_isset(cpu, mm->cpu_vm_mask))  {
 261                 get_new_mmu_context(mm, cpu);
 262 #ifdef CONFIG_MIPS_MT_SMTC
 263                 /* See comments for similar code above */
 264                 prevvpe = dvpe();
 265                 oldasid = (read_c0_entryhi() & ASID_MASK);
 266                 if (smtc_live_asid[mytlb][oldasid]) {
 267                         smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
 268                         if(smtc_live_asid[mytlb][oldasid] == 0)
 269                                 smtc_flush_tlb_asid(oldasid);
 270                 }
 271                 /* See comments for similar code above */
 272                 write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
 273                                 | cpu_asid(cpu, mm));
 274                 ehb(); /* Make sure it propagates to TCStatus */
 275                 evpe(prevvpe);
 276 #else /* not CONFIG_MIPS_MT_SMTC */
 277                 write_c0_entryhi(cpu_asid(cpu, mm));
 278 #endif /* CONFIG_MIPS_MT_SMTC */
 279         } else {
 280                 /* will get a new context next time */
 281 #ifndef CONFIG_MIPS_MT_SMTC
 282                 cpu_context(cpu, mm) = 0;
 283 #else /* SMTC */
 284                 int i;
 285
 286                 /* SMTC shares the TLB (and ASIDs) across VPEs */
 287                 for_each_online_cpu(i) {
 288                     if((smtc_status & SMTC_TLB_SHARED)
 289                     || (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id))
 290                         cpu_context(i, mm) = 0;
 291                 }
 292 #endif /* CONFIG_MIPS_MT_SMTC */
 293         }
 294         local_irq_restore(flags);
 295 }
 296
 297 #endif /* _ASM_MMU_CONTEXT_H */