arch/sparc/include/asm/mmu_context_64.h

   1 #ifndef __SPARC64_MMU_CONTEXT_H
   2 #define __SPARC64_MMU_CONTEXT_H
   3
   4 /* Derived heavily from Linus's Alpha/AXP ASN code... */
   5
   6 #ifndef __ASSEMBLY__
   7
   8 #include <linux/spinlock.h>
   9 #include <asm/system.h>
  10 #include <asm/spitfire.h>
  11 #include <asm-generic/mm_hooks.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 #ifdef CONFIG_SMP
  23 extern void smp_new_mmu_context_version(void);
  24 #else
  25 #define smp_new_mmu_context_version() do { } while (0)
  26 #endif
  27
  28 extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
  29 extern void destroy_context(struct mm_struct *mm);
  30
  31 extern void __tsb_context_switch(unsigned long pgd_pa,
  32                                  struct tsb_config *tsb_base,
  33                                  struct tsb_config *tsb_huge,
  34                                  unsigned long tsb_descr_pa);
  35
  36 static inline void tsb_context_switch(struct mm_struct *mm)
  37 {
  38         __tsb_context_switch(__pa(mm->pgd),
  39                              &mm->context.tsb_block[0],
  40 #ifdef CONFIG_HUGETLB_PAGE
  41                              (mm->context.tsb_block[1].tsb ?
  42                               &mm->context.tsb_block[1] :
  43                               NULL)
  44 #else
  45                              NULL
  46 #endif
  47                              , __pa(&mm->context.tsb_descr[0]));
  48 }
  49
  50 extern void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long mm_rss);
  51 #ifdef CONFIG_SMP
  52 extern void smp_tsb_sync(struct mm_struct *mm);
  53 #else
  54 #define smp_tsb_sync(__mm) do { } while (0)
  55 #endif
  56
  57 /* Set MMU context in the actual hardware. */
  58 #define load_secondary_context(__mm) \
  59         __asm__ __volatile__( \
  60         "\n661: stxa            %0, [%1] %2\n" \
  61         "       .section        .sun4v_1insn_patch, \"ax\"\n" \
  62         "       .word           661b\n" \
  63         "       stxa            %0, [%1] %3\n" \
  64         "       .previous\n" \
  65         "       flush           %%g6\n" \
  66         : /* No outputs */ \
  67         : "r" (CTX_HWBITS((__mm)->context)), \
  68           "r" (SECONDARY_CONTEXT), "i" (ASI_DMMU), "i" (ASI_MMU))
  69
  70 extern void __flush_tlb_mm(unsigned long, unsigned long);
  71
  72 /* Switch the current MM context.  Interrupts are disabled.  */
  73 static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
  74 {
  75         unsigned long ctx_valid, flags;
  76         int cpu;
  77
  78         if (unlikely(mm == &init_mm))
  79                 return;
  80
  81         spin_lock_irqsave(&mm->context.lock, flags);
  82         ctx_valid = CTX_VALID(mm->context);
  83         if (!ctx_valid)
  84                 get_new_mmu_context(mm);
  85
  86         /* We have to be extremely careful here or else we will miss
  87          * a TSB grow if we switch back and forth between a kernel
  88          * thread and an address space which has it's TSB size increased
  89          * on another processor.
  90          *
  91          * It is possible to play some games in order to optimize the
  92          * switch, but the safest thing to do is to unconditionally
  93          * perform the secondary context load and the TSB context switch.
  94          *
  95          * For reference the bad case is, for address space "A":
  96          *
  97          *              CPU 0                   CPU 1
  98          *      run address space A
  99          *      set cpu0's bits in cpu_vm_mask
 100          *      switch to kernel thread, borrow
 101          *      address space A via entry_lazy_tlb
 102          *                                      run address space A
 103          *                                      set cpu1's bit in cpu_vm_mask
 104          *                                      flush_tlb_pending()
 105          *                                      reset cpu_vm_mask to just cpu1
 106          *                                      TSB grow
 107          *      run address space A
 108          *      context was valid, so skip
 109          *      TSB context switch
 110          *
 111          * At that point cpu0 continues to use a stale TSB, the one from
 112          * before the TSB grow performed on cpu1.  cpu1 did not cross-call
 113          * cpu0 to update it's TSB because at that point the cpu_vm_mask
 114          * only had cpu1 set in it.
 115          */
 116         load_secondary_context(mm);
 117         tsb_context_switch(mm);
 118
 119         /* Any time a processor runs a context on an address space
 120          * for the first time, we must flush that context out of the
 121          * local TLB.
 122          */
 123         cpu = smp_processor_id();
 124         if (!ctx_valid || !cpumask_test_cpu(cpu, mm_cpumask(mm))) {
 125                 cpumask_set_cpu(cpu, mm_cpumask(mm));
 126                 __flush_tlb_mm(CTX_HWBITS(mm->context),
 127                                SECONDARY_CONTEXT);
 128         }
 129         spin_unlock_irqrestore(&mm->context.lock, flags);
 130 }
 131
 132 #define deactivate_mm(tsk,mm)   do { } while (0)
 133
 134 /* Activate a new MM instance for the current task. */
 135 static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm)
 136 {
 137         unsigned long flags;
 138         int cpu;
 139
 140         spin_lock_irqsave(&mm->context.lock, flags);
 141         if (!CTX_VALID(mm->context))
 142                 get_new_mmu_context(mm);
 143         cpu = smp_processor_id();
 144         if (!cpumask_test_cpu(cpu, mm_cpumask(mm)))
 145                 cpumask_set_cpu(cpu, mm_cpumask(mm));
 146
 147         load_secondary_context(mm);
 148         __flush_tlb_mm(CTX_HWBITS(mm->context), SECONDARY_CONTEXT);
 149         tsb_context_switch(mm);
 150         spin_unlock_irqrestore(&mm->context.lock, flags);
 151 }
 152
 153 #endif /* !(__ASSEMBLY__) */
 154
 155 #endif /* !(__SPARC64_MMU_CONTEXT_H) */