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