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-rw-r--r--include/asm-ia64/mmu_context.h80
1 files changed, 41 insertions, 39 deletions
diff --git a/include/asm-ia64/mmu_context.h b/include/asm-ia64/mmu_context.h
index 8d9b30b5f7d4..b5c65081a3aa 100644
--- a/include/asm-ia64/mmu_context.h
+++ b/include/asm-ia64/mmu_context.h
@@ -7,12 +7,13 @@
7 */ 7 */
8 8
9/* 9/*
10 * Routines to manage the allocation of task context numbers. Task context numbers are 10 * Routines to manage the allocation of task context numbers. Task context
11 * used to reduce or eliminate the need to perform TLB flushes due to context switches. 11 * numbers are used to reduce or eliminate the need to perform TLB flushes
12 * Context numbers are implemented using ia-64 region ids. Since the IA-64 TLB does not 12 * due to context switches. Context numbers are implemented using ia-64
13 * consider the region number when performing a TLB lookup, we need to assign a unique 13 * region ids. Since the IA-64 TLB does not consider the region number when
14 * region id to each region in a process. We use the least significant three bits in a 14 * performing a TLB lookup, we need to assign a unique region id to each
15 * region id for this purpose. 15 * region in a process. We use the least significant three bits in aregion
16 * id for this purpose.
16 */ 17 */
17 18
18#define IA64_REGION_ID_KERNEL 0 /* the kernel's region id (tlb.c depends on this being 0) */ 19#define IA64_REGION_ID_KERNEL 0 /* the kernel's region id (tlb.c depends on this being 0) */
@@ -51,10 +52,10 @@ enter_lazy_tlb (struct mm_struct *mm, struct task_struct *tsk)
51} 52}
52 53
53/* 54/*
54 * When the context counter wraps around all TLBs need to be flushed because an old 55 * When the context counter wraps around all TLBs need to be flushed because
55 * context number might have been reused. This is signalled by the ia64_need_tlb_flush 56 * an old context number might have been reused. This is signalled by the
56 * per-CPU variable, which is checked in the routine below. Called by activate_mm(). 57 * ia64_need_tlb_flush per-CPU variable, which is checked in the routine
57 * <efocht@ess.nec.de> 58 * below. Called by activate_mm(). <efocht@ess.nec.de>
58 */ 59 */
59static inline void 60static inline void
60delayed_tlb_flush (void) 61delayed_tlb_flush (void)
@@ -64,11 +65,9 @@ delayed_tlb_flush (void)
64 65
65 if (unlikely(__ia64_per_cpu_var(ia64_need_tlb_flush))) { 66 if (unlikely(__ia64_per_cpu_var(ia64_need_tlb_flush))) {
66 spin_lock_irqsave(&ia64_ctx.lock, flags); 67 spin_lock_irqsave(&ia64_ctx.lock, flags);
67 { 68 if (__ia64_per_cpu_var(ia64_need_tlb_flush)) {
68 if (__ia64_per_cpu_var(ia64_need_tlb_flush)) { 69 local_flush_tlb_all();
69 local_flush_tlb_all(); 70 __ia64_per_cpu_var(ia64_need_tlb_flush) = 0;
70 __ia64_per_cpu_var(ia64_need_tlb_flush) = 0;
71 }
72 } 71 }
73 spin_unlock_irqrestore(&ia64_ctx.lock, flags); 72 spin_unlock_irqrestore(&ia64_ctx.lock, flags);
74 } 73 }
@@ -80,27 +79,27 @@ get_mmu_context (struct mm_struct *mm)
80 unsigned long flags; 79 unsigned long flags;
81 nv_mm_context_t context = mm->context; 80 nv_mm_context_t context = mm->context;
82 81
83 if (unlikely(!context)) { 82 if (likely(context))
84 spin_lock_irqsave(&ia64_ctx.lock, flags); 83 goto out;
85 { 84
86 /* re-check, now that we've got the lock: */ 85 spin_lock_irqsave(&ia64_ctx.lock, flags);
87 context = mm->context; 86 /* re-check, now that we've got the lock: */
88 if (context == 0) { 87 context = mm->context;
89 cpus_clear(mm->cpu_vm_mask); 88 if (context == 0) {
90 if (ia64_ctx.next >= ia64_ctx.limit) { 89 cpus_clear(mm->cpu_vm_mask);
91 ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap, 90 if (ia64_ctx.next >= ia64_ctx.limit) {
92 ia64_ctx.max_ctx, ia64_ctx.next); 91 ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
93 ia64_ctx.limit = find_next_bit(ia64_ctx.bitmap, 92 ia64_ctx.max_ctx, ia64_ctx.next);
94 ia64_ctx.max_ctx, ia64_ctx.next); 93 ia64_ctx.limit = find_next_bit(ia64_ctx.bitmap,
95 if (ia64_ctx.next >= ia64_ctx.max_ctx) 94 ia64_ctx.max_ctx, ia64_ctx.next);
96 wrap_mmu_context(mm); 95 if (ia64_ctx.next >= ia64_ctx.max_ctx)
97 } 96 wrap_mmu_context(mm);
98 mm->context = context = ia64_ctx.next++;
99 __set_bit(context, ia64_ctx.bitmap);
100 }
101 } 97 }
102 spin_unlock_irqrestore(&ia64_ctx.lock, flags); 98 mm->context = context = ia64_ctx.next++;
99 __set_bit(context, ia64_ctx.bitmap);
103 } 100 }
101 spin_unlock_irqrestore(&ia64_ctx.lock, flags);
102out:
104 /* 103 /*
105 * Ensure we're not starting to use "context" before any old 104 * Ensure we're not starting to use "context" before any old
106 * uses of it are gone from our TLB. 105 * uses of it are gone from our TLB.
@@ -111,8 +110,8 @@ get_mmu_context (struct mm_struct *mm)
111} 110}
112 111
113/* 112/*
114 * Initialize context number to some sane value. MM is guaranteed to be a brand-new 113 * Initialize context number to some sane value. MM is guaranteed to be a
115 * address-space, so no TLB flushing is needed, ever. 114 * brand-new address-space, so no TLB flushing is needed, ever.
116 */ 115 */
117static inline int 116static inline int
118init_new_context (struct task_struct *p, struct mm_struct *mm) 117init_new_context (struct task_struct *p, struct mm_struct *mm)
@@ -173,7 +172,10 @@ activate_context (struct mm_struct *mm)
173 if (!cpu_isset(smp_processor_id(), mm->cpu_vm_mask)) 172 if (!cpu_isset(smp_processor_id(), mm->cpu_vm_mask))
174 cpu_set(smp_processor_id(), mm->cpu_vm_mask); 173 cpu_set(smp_processor_id(), mm->cpu_vm_mask);
175 reload_context(context); 174 reload_context(context);
176 /* in the unlikely event of a TLB-flush by another thread, redo the load: */ 175 /*
176 * in the unlikely event of a TLB-flush by another thread,
177 * redo the load.
178 */
177 } while (unlikely(context != mm->context)); 179 } while (unlikely(context != mm->context));
178} 180}
179 181
@@ -186,8 +188,8 @@ static inline void
186activate_mm (struct mm_struct *prev, struct mm_struct *next) 188activate_mm (struct mm_struct *prev, struct mm_struct *next)
187{ 189{
188 /* 190 /*
189 * We may get interrupts here, but that's OK because interrupt handlers cannot 191 * We may get interrupts here, but that's OK because interrupt
190 * touch user-space. 192 * handlers cannot touch user-space.
191 */ 193 */
192 ia64_set_kr(IA64_KR_PT_BASE, __pa(next->pgd)); 194 ia64_set_kr(IA64_KR_PT_BASE, __pa(next->pgd));
193 activate_context(next); 195 activate_context(next);