include/asm-i386/mach-xen/asm/mmu_context.h

   1 #ifndef __I386_SCHED_H
   2 #define __I386_SCHED_H
   3
   4 #include <linux/config.h>
   5 #include <asm/desc.h>
   6 #include <asm/atomic.h>
   7 #include <asm/pgalloc.h>
   8 #include <asm/tlbflush.h>
   9
  10 /*
  11  * Used for LDT copy/destruction.
  12  */
  13 int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
  14 void destroy_context(struct mm_struct *mm);
  15
  16
  17 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  18 {
  19 #if 0 /* XEN: no lazy tlb */
  20         unsigned cpu = smp_processor_id();
  21         if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
  22                 per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_LAZY;
  23 #endif
  24 }
  25
  26 #define prepare_arch_switch(next)       __prepare_arch_switch()
  27
  28 static inline void __prepare_arch_switch(void)
  29 {
  30         /*
  31          * Save away %fs and %gs. No need to save %es and %ds, as those
  32          * are always kernel segments while inside the kernel. Must
  33          * happen before reload of cr3/ldt (i.e., not in __switch_to).
  34          */
  35         asm volatile ( "mov %%fs,%0 ; mov %%gs,%1"
  36                 : "=m" (current->thread.fs),
  37                   "=m" (current->thread.gs));
  38         asm volatile ( "movl %0,%%fs ; movl %0,%%gs"
  39                 : : "r" (0) );
  40 }
  41
  42 extern void mm_pin(struct mm_struct *mm);
  43 extern void mm_unpin(struct mm_struct *mm);
  44 void mm_pin_all(void);
  45
  46 static inline void switch_mm(struct mm_struct *prev,
  47                              struct mm_struct *next,
  48                              struct task_struct *tsk)
  49 {
  50         int cpu = smp_processor_id();
  51         struct mmuext_op _op[2], *op = _op;
  52
  53         if (likely(prev != next)) {
  54                 BUG_ON(!xen_feature(XENFEAT_writable_page_tables) &&
  55                        !test_bit(PG_pinned, &virt_to_page(next->pgd)->flags));
  56
  57                 /* stop flush ipis for the previous mm */
  58                 cpu_clear(cpu, prev->cpu_vm_mask);
  59 #if 0 /* XEN: no lazy tlb */
  60                 per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_OK;
  61                 per_cpu(cpu_tlbstate, cpu).active_mm = next;
  62 #endif
  63                 cpu_set(cpu, next->cpu_vm_mask);
  64
  65                 /* Re-load page tables: load_cr3(next->pgd) */
  66                 op->cmd = MMUEXT_NEW_BASEPTR;
  67                 op->arg1.mfn = pfn_to_mfn(__pa(next->pgd) >> PAGE_SHIFT);
  68                 op++;
  69
  70                 /*
  71                  * load the LDT, if the LDT is different:
  72                  */
  73                 if (unlikely(prev->context.ldt != next->context.ldt)) {
  74                         /* load_LDT_nolock(&next->context, cpu) */
  75                         op->cmd = MMUEXT_SET_LDT;
  76                         op->arg1.linear_addr = (unsigned long)next->context.ldt;
  77                         op->arg2.nr_ents     = next->context.size;
  78                         op++;
  79                 }
  80
  81                 BUG_ON(HYPERVISOR_mmuext_op(_op, op-_op, NULL, DOMID_SELF));
  82         }
  83 #if 0 /* XEN: no lazy tlb */
  84         else {
  85                 per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_OK;
  86                 BUG_ON(per_cpu(cpu_tlbstate, cpu).active_mm != next);
  87
  88                 if (!cpu_test_and_set(cpu, next->cpu_vm_mask)) {
  89                         /* We were in lazy tlb mode and leave_mm disabled
  90                          * tlb flush IPI delivery. We must reload %cr3.
  91                          */
  92                         load_cr3(next->pgd);
  93                         load_LDT_nolock(&next->context, cpu);
  94                 }
  95         }
  96 #endif
  97 }
  98
  99 #define deactivate_mm(tsk, mm) \
 100         asm("movl %0,%%fs ; movl %0,%%gs": :"r" (0))
 101
 102 static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
 103 {
 104         if (!test_bit(PG_pinned, &virt_to_page(next->pgd)->flags))
 105                 mm_pin(next);
 106         switch_mm(prev, next, NULL);
 107 }
 108
 109 #endif