include/asm-sparc64/mmu_context.h

   1 /* $Id: mmu_context.h,v 1.54 2002/02/09 19:49:31 davem Exp $ */
   2 #ifndef __SPARC64_MMU_CONTEXT_H
   3 #define __SPARC64_MMU_CONTEXT_H
   4
   5 /* Derived heavily from Linus's Alpha/AXP ASN code... */
   6
   7 #ifndef __ASSEMBLY__
   8
   9 #include <linux/spinlock.h>
  10 #include <asm/system.h>
  11 #include <asm/spitfire.h>
  12
  13 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  14 {
  15 }
  16
  17 extern spinlock_t ctx_alloc_lock;
  18 extern unsigned long tlb_context_cache;
  19 extern unsigned long mmu_context_bmap[];
  20
  21 extern void get_new_mmu_context(struct mm_struct *mm);
  22
  23 /* Initialize a new mmu context.  This is invoked when a new
  24  * address space instance (unique or shared) is instantiated.
  25  * This just needs to set mm->context to an invalid context.
  26  */
  27 #define init_new_context(__tsk, __mm)   \
  28         (((__mm)->context.sparc64_ctx_val = 0UL), 0)
  29
  30 /* Destroy a dead context.  This occurs when mmput drops the
  31  * mm_users count to zero, the mmaps have been released, and
  32  * all the page tables have been flushed.  Our job is to destroy
  33  * any remaining processor-specific state, and in the sparc64
  34  * case this just means freeing up the mmu context ID held by
  35  * this task if valid.
  36  */
  37 #define destroy_context(__mm)                                   \
  38 do {    spin_lock(&ctx_alloc_lock);                             \
  39         if (CTX_VALID((__mm)->context)) {                       \
  40                 unsigned long nr = CTX_NRBITS((__mm)->context); \
  41                 mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63)); \
  42         }                                                       \
  43         spin_unlock(&ctx_alloc_lock);                           \
  44 } while(0)
  45
  46 /* Reload the two core values used by TLB miss handler
  47  * processing on sparc64.  They are:
  48  * 1) The physical address of mm->pgd, when full page
  49  *    table walks are necessary, this is where the
  50  *    search begins.
  51  * 2) A "PGD cache".  For 32-bit tasks only pgd[0] is
  52  *    ever used since that maps the entire low 4GB
  53  *    completely.  To speed up TLB miss processing we
  54  *    make this value available to the handlers.  This
  55  *    decreases the amount of memory traffic incurred.
  56  */
  57 #define reload_tlbmiss_state(__tsk, __mm) \
  58 do { \
  59         register unsigned long paddr asm("o5"); \
  60         register unsigned long pgd_cache asm("o4"); \
  61         paddr = __pa((__mm)->pgd); \
  62         pgd_cache = 0UL; \
  63         if (task_thread_info(__tsk)->flags & _TIF_32BIT) \
  64                 pgd_cache = get_pgd_cache((__mm)->pgd); \
  65         __asm__ __volatile__("wrpr      %%g0, 0x494, %%pstate\n\t" \
  66                              "mov       %3, %%g4\n\t" \
  67                              "mov       %0, %%g7\n\t" \
  68                              "stxa      %1, [%%g4] %2\n\t" \
  69                              "membar    #Sync\n\t" \
  70                              "wrpr      %%g0, 0x096, %%pstate" \
  71                              : /* no outputs */ \
  72                              : "r" (paddr), "r" (pgd_cache),\
  73                                "i" (ASI_DMMU), "i" (TSB_REG)); \
  74 } while(0)
  75
  76 /* Set MMU context in the actual hardware. */
  77 #define load_secondary_context(__mm) \
  78         __asm__ __volatile__("stxa      %0, [%1] %2\n\t" \
  79                              "flush     %%g6" \
  80                              : /* No outputs */ \
  81                              : "r" (CTX_HWBITS((__mm)->context)), \
  82                                "r" (SECONDARY_CONTEXT), "i" (ASI_DMMU))
  83
  84 extern void __flush_tlb_mm(unsigned long, unsigned long);
  85
  86 /* Switch the current MM context. */
  87 static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
  88 {
  89         unsigned long ctx_valid;
  90         int cpu;
  91
  92         /* Note: page_table_lock is used here to serialize switch_mm
  93          * and activate_mm, and their calls to get_new_mmu_context.
  94          * This use of page_table_lock is unrelated to its other uses.
  95          */
  96         spin_lock(&mm->page_table_lock);
  97         ctx_valid = CTX_VALID(mm->context);
  98         if (!ctx_valid)
  99                 get_new_mmu_context(mm);
 100         spin_unlock(&mm->page_table_lock);
 101
 102         if (!ctx_valid || (old_mm != mm)) {
 103                 load_secondary_context(mm);
 104                 reload_tlbmiss_state(tsk, mm);
 105         }
 106
 107         /* Even if (mm == old_mm) we _must_ check
 108          * the cpu_vm_mask.  If we do not we could
 109          * corrupt the TLB state because of how
 110          * smp_flush_tlb_{page,range,mm} on sparc64
 111          * and lazy tlb switches work. -DaveM
 112          */
 113         cpu = smp_processor_id();
 114         if (!ctx_valid || !cpu_isset(cpu, mm->cpu_vm_mask)) {
 115                 cpu_set(cpu, mm->cpu_vm_mask);
 116                 __flush_tlb_mm(CTX_HWBITS(mm->context),
 117                                SECONDARY_CONTEXT);
 118         }
 119 }
 120
 121 #define deactivate_mm(tsk,mm)   do { } while (0)
 122
 123 /* Activate a new MM instance for the current task. */
 124 static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm)
 125 {
 126         int cpu;
 127
 128         /* Note: page_table_lock is used here to serialize switch_mm
 129          * and activate_mm, and their calls to get_new_mmu_context.
 130          * This use of page_table_lock is unrelated to its other uses.
 131          */
 132         spin_lock(&mm->page_table_lock);
 133         if (!CTX_VALID(mm->context))
 134                 get_new_mmu_context(mm);
 135         cpu = smp_processor_id();
 136         if (!cpu_isset(cpu, mm->cpu_vm_mask))
 137                 cpu_set(cpu, mm->cpu_vm_mask);
 138         spin_unlock(&mm->page_table_lock);
 139
 140         load_secondary_context(mm);
 141         __flush_tlb_mm(CTX_HWBITS(mm->context), SECONDARY_CONTEXT);
 142         reload_tlbmiss_state(current, mm);
 143 }
 144
 145 #endif /* !(__ASSEMBLY__) */
 146
 147 #endif /* !(__SPARC64_MMU_CONTEXT_H) */