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

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