release/src-rt-6.x.4708/linux/linux-2.6.36/arch/x86/include/asm/mmu_context.h

   1 #ifndef _ASM_X86_MMU_CONTEXT_H
   2 #define _ASM_X86_MMU_CONTEXT_H
   3
   4 #include <asm/desc.h>
   5 #include <asm/atomic.h>
   6 #include <asm/pgalloc.h>
   7 #include <asm/tlbflush.h>
   8 #include <asm/paravirt.h>
   9 #ifndef CONFIG_PARAVIRT
  10 #include <asm-generic/mm_hooks.h>
  11
  12 static inline void paravirt_activate_mm(struct mm_struct *prev,
  13                                         struct mm_struct *next)
  14 {
  15 }
  16 #endif  /* !CONFIG_PARAVIRT */
  17
  18 /*
  19  * Used for LDT copy/destruction.
  20  */
  21 int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
  22 void destroy_context(struct mm_struct *mm);
  23
  24
  25 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  26 {
  27 #ifdef CONFIG_SMP
  28         if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK)
  29                 percpu_write(cpu_tlbstate.state, TLBSTATE_LAZY);
  30 #endif
  31 }
  32
  33 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  34                              struct task_struct *tsk)
  35 {
  36         unsigned cpu = smp_processor_id();
  37
  38         if (likely(prev != next)) {
  39 #ifdef CONFIG_SMP
  40                 percpu_write(cpu_tlbstate.state, TLBSTATE_OK);
  41                 percpu_write(cpu_tlbstate.active_mm, next);
  42 #endif
  43                 cpumask_set_cpu(cpu, mm_cpumask(next));
  44
  45                 /* Re-load page tables */
  46                 load_cr3(next->pgd);
  47
  48                 /* stop flush ipis for the previous mm */
  49                 cpumask_clear_cpu(cpu, mm_cpumask(prev));
  50
  51                 /*
  52                  * load the LDT, if the LDT is different:
  53                  */
  54                 if (unlikely(prev->context.ldt != next->context.ldt))
  55                         load_LDT_nolock(&next->context);
  56         }
  57 #ifdef CONFIG_SMP
  58         else {
  59                 percpu_write(cpu_tlbstate.state, TLBSTATE_OK);
  60                 BUG_ON(percpu_read(cpu_tlbstate.active_mm) != next);
  61
  62                 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next))) {
  63                         /* We were in lazy tlb mode and leave_mm disabled
  64                          * tlb flush IPI delivery. We must reload CR3
  65                          * to make sure to use no freed page tables.
  66                          */
  67                         load_cr3(next->pgd);
  68                         load_LDT_nolock(&next->context);
  69                 }
  70         }
  71 #endif
  72 }
  73
  74 #define activate_mm(prev, next)                 \
  75 do {                                            \
  76         paravirt_activate_mm((prev), (next));   \
  77         switch_mm((prev), (next), NULL);        \
  78 } while (0);
  79
  80 #ifdef CONFIG_X86_32
  81 #define deactivate_mm(tsk, mm)                  \
  82 do {                                            \
  83         lazy_load_gs(0);                        \
  84 } while (0)
  85 #else
  86 #define deactivate_mm(tsk, mm)                  \
  87 do {                                            \
  88         load_gs_index(0);                       \
  89         loadsegment(fs, 0);                     \
  90 } while (0)
  91 #endif
  92
  93 #endif /* _ASM_X86_MMU_CONTEXT_H */