*/
/*
- * Routines to manage the allocation of task context numbers. Task context numbers are
- * used to reduce or eliminate the need to perform TLB flushes due to context switches.
- * Context numbers are implemented using ia-64 region ids. Since the IA-64 TLB does not
- * consider the region number when performing a TLB lookup, we need to assign a unique
- * region id to each region in a process. We use the least significant three bits in a
- * region id for this purpose.
+ * Routines to manage the allocation of task context numbers. Task context
+ * numbers are used to reduce or eliminate the need to perform TLB flushes
+ * due to context switches. Context numbers are implemented using ia-64
+ * region ids. Since the IA-64 TLB does not consider the region number when
+ * performing a TLB lookup, we need to assign a unique region id to each
+ * region in a process. We use the least significant three bits in aregion
+ * id for this purpose.
*/
#define IA64_REGION_ID_KERNEL 0 /* the kernel's region id (tlb.c depends on this being 0) */
#include <linux/spinlock.h>
#include <asm/processor.h>
+#include <asm-generic/mm_hooks.h>
struct ia64_ctx {
spinlock_t lock;
unsigned int next; /* next context number to use */
- unsigned int limit; /* next >= limit => must call wrap_mmu_context() */
- unsigned int max_ctx; /* max. context value supported by all CPUs */
+ unsigned int limit; /* available free range */
+ unsigned int max_ctx; /* max. context value supported by all CPUs */
+ /* call wrap_mmu_context when next >= max */
+ unsigned long *bitmap; /* bitmap size is max_ctx+1 */
+ unsigned long *flushmap;/* pending rid to be flushed */
};
extern struct ia64_ctx ia64_ctx;
DECLARE_PER_CPU(u8, ia64_need_tlb_flush);
+extern void mmu_context_init (void);
extern void wrap_mmu_context (struct mm_struct *mm);
static inline void
}
/*
- * When the context counter wraps around all TLBs need to be flushed because an old
- * context number might have been reused. This is signalled by the ia64_need_tlb_flush
- * per-CPU variable, which is checked in the routine below. Called by activate_mm().
- * <efocht@ess.nec.de>
+ * When the context counter wraps around all TLBs need to be flushed because
+ * an old context number might have been reused. This is signalled by the
+ * ia64_need_tlb_flush per-CPU variable, which is checked in the routine
+ * below. Called by activate_mm(). <efocht@ess.nec.de>
*/
static inline void
delayed_tlb_flush (void)
if (unlikely(__ia64_per_cpu_var(ia64_need_tlb_flush))) {
spin_lock_irqsave(&ia64_ctx.lock, flags);
- {
- if (__ia64_per_cpu_var(ia64_need_tlb_flush)) {
- local_flush_tlb_all();
- __ia64_per_cpu_var(ia64_need_tlb_flush) = 0;
- }
+ if (__ia64_per_cpu_var(ia64_need_tlb_flush)) {
+ local_flush_tlb_all();
+ __ia64_per_cpu_var(ia64_need_tlb_flush) = 0;
}
spin_unlock_irqrestore(&ia64_ctx.lock, flags);
}
unsigned long flags;
nv_mm_context_t context = mm->context;
- if (unlikely(!context)) {
- spin_lock_irqsave(&ia64_ctx.lock, flags);
- {
- /* re-check, now that we've got the lock: */
- context = mm->context;
- if (context == 0) {
- cpus_clear(mm->cpu_vm_mask);
- if (ia64_ctx.next >= ia64_ctx.limit)
- wrap_mmu_context(mm);
- mm->context = context = ia64_ctx.next++;
- }
+ if (likely(context))
+ goto out;
+
+ spin_lock_irqsave(&ia64_ctx.lock, flags);
+ /* re-check, now that we've got the lock: */
+ context = mm->context;
+ if (context == 0) {
+ cpus_clear(mm->cpu_vm_mask);
+ if (ia64_ctx.next >= ia64_ctx.limit) {
+ ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
+ ia64_ctx.max_ctx, ia64_ctx.next);
+ ia64_ctx.limit = find_next_bit(ia64_ctx.bitmap,
+ ia64_ctx.max_ctx, ia64_ctx.next);
+ if (ia64_ctx.next >= ia64_ctx.max_ctx)
+ wrap_mmu_context(mm);
}
- spin_unlock_irqrestore(&ia64_ctx.lock, flags);
+ mm->context = context = ia64_ctx.next++;
+ __set_bit(context, ia64_ctx.bitmap);
}
+ spin_unlock_irqrestore(&ia64_ctx.lock, flags);
+out:
/*
* Ensure we're not starting to use "context" before any old
* uses of it are gone from our TLB.
}
/*
- * Initialize context number to some sane value. MM is guaranteed to be a brand-new
- * address-space, so no TLB flushing is needed, ever.
+ * Initialize context number to some sane value. MM is guaranteed to be a
+ * brand-new address-space, so no TLB flushing is needed, ever.
*/
static inline int
init_new_context (struct task_struct *p, struct mm_struct *mm)
if (!cpu_isset(smp_processor_id(), mm->cpu_vm_mask))
cpu_set(smp_processor_id(), mm->cpu_vm_mask);
reload_context(context);
- /* in the unlikely event of a TLB-flush by another thread, redo the load: */
+ /*
+ * in the unlikely event of a TLB-flush by another thread,
+ * redo the load.
+ */
} while (unlikely(context != mm->context));
}
activate_mm (struct mm_struct *prev, struct mm_struct *next)
{
/*
- * We may get interrupts here, but that's OK because interrupt handlers cannot
- * touch user-space.
+ * We may get interrupts here, but that's OK because interrupt
+ * handlers cannot touch user-space.
*/
ia64_set_kr(IA64_KR_PT_BASE, __pa(next->pgd));
activate_context(next);
git.openpandora.org / pandora-kernel.git / blobdiff