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