--- /dev/null
+#ifndef _ASM_IA64_MMU_CONTEXT_H
+#define _ASM_IA64_MMU_CONTEXT_H
+
+/*
+ * Copyright (C) 1998-2002 Hewlett-Packard Co
+ * David Mosberger-Tang <davidm@hpl.hp.com>
+ */
+
+/*
+ * 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) */
+
+#define ia64_rid(ctx,addr) (((ctx) << 3) | (addr >> 61))
+
+# include <asm/page.h>
+# ifndef __ASSEMBLY__
+
+#include <linux/compiler.h>
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#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; /* 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
+enter_lazy_tlb (struct mm_struct *mm, struct task_struct *tsk)
+{
+}
+
+/*
+ * 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)
+{
+ extern void local_flush_tlb_all (void);
+ unsigned long flags;
+
+ 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;
+ }
+ spin_unlock_irqrestore(&ia64_ctx.lock, flags);
+ }
+}
+
+static inline nv_mm_context_t
+get_mmu_context (struct mm_struct *mm)
+{
+ unsigned long flags;
+ nv_mm_context_t context = mm->context;
+
+ 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) {
+ cpumask_clear(mm_cpumask(mm));
+ 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);
+ }
+ 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.
+ */
+ delayed_tlb_flush();
+
+ return context;
+}
+
+/*
+ * 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)
+{
+ mm->context = 0;
+ return 0;
+}
+
+static inline void
+destroy_context (struct mm_struct *mm)
+{
+ /* Nothing to do. */
+}
+
+static inline void
+reload_context (nv_mm_context_t context)
+{
+ unsigned long rid;
+ unsigned long rid_incr = 0;
+ unsigned long rr0, rr1, rr2, rr3, rr4, old_rr4;
+
+ old_rr4 = ia64_get_rr(RGN_BASE(RGN_HPAGE));
+ rid = context << 3; /* make space for encoding the region number */
+ rid_incr = 1 << 8;
+
+ /* encode the region id, preferred page size, and VHPT enable bit: */
+ rr0 = (rid << 8) | (PAGE_SHIFT << 2) | 1;
+ rr1 = rr0 + 1*rid_incr;
+ rr2 = rr0 + 2*rid_incr;
+ rr3 = rr0 + 3*rid_incr;
+ rr4 = rr0 + 4*rid_incr;
+#ifdef CONFIG_HUGETLB_PAGE
+ rr4 = (rr4 & (~(0xfcUL))) | (old_rr4 & 0xfc);
+
+# if RGN_HPAGE != 4
+# error "reload_context assumes RGN_HPAGE is 4"
+# endif
+#endif
+
+ ia64_set_rr0_to_rr4(rr0, rr1, rr2, rr3, rr4);
+ ia64_srlz_i(); /* srlz.i implies srlz.d */
+}
+
+/*
+ * Must be called with preemption off
+ */
+static inline void
+activate_context (struct mm_struct *mm)
+{
+ nv_mm_context_t context;
+
+ do {
+ context = get_mmu_context(mm);
+ if (!cpumask_test_cpu(smp_processor_id(), mm_cpumask(mm)))
+ cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
+ reload_context(context);
+ /*
+ * in the unlikely event of a TLB-flush by another thread,
+ * redo the load.
+ */
+ } while (unlikely(context != mm->context));
+}
+
+#define deactivate_mm(tsk,mm) do { } while (0)
+
+/*
+ * Switch from address space PREV to address space NEXT.
+ */
+static inline void
+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.
+ */
+ ia64_set_kr(IA64_KR_PT_BASE, __pa(next->pgd));
+ activate_context(next);
+}
+
+#define switch_mm(prev_mm,next_mm,next_task) activate_mm(prev_mm, next_mm)
+
+# endif /* ! __ASSEMBLY__ */
+#endif /* _ASM_IA64_MMU_CONTEXT_H */
Code Review / kvmfornfv.git / blobdiff