195 строки
5.2 KiB
C
195 строки
5.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_IA64_MMU_CONTEXT_H
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#define _ASM_IA64_MMU_CONTEXT_H
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/*
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* Copyright (C) 1998-2002 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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*/
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/*
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* Routines to manage the allocation of task context numbers. Task context
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* numbers are used to reduce or eliminate the need to perform TLB flushes
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* due to context switches. Context numbers are implemented using ia-64
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* region ids. Since the IA-64 TLB does not consider the region number when
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* performing a TLB lookup, we need to assign a unique region id to each
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* region in a process. We use the least significant three bits in aregion
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* id for this purpose.
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*/
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#define IA64_REGION_ID_KERNEL 0 /* the kernel's region id (tlb.c depends on this being 0) */
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#define ia64_rid(ctx,addr) (((ctx) << 3) | (addr >> 61))
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# include <asm/page.h>
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# ifndef __ASSEMBLY__
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#include <linux/compiler.h>
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#include <linux/percpu.h>
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#include <linux/sched.h>
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#include <linux/mm_types.h>
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#include <linux/spinlock.h>
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#include <asm/processor.h>
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#include <asm-generic/mm_hooks.h>
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struct ia64_ctx {
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spinlock_t lock;
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unsigned int next; /* next context number to use */
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unsigned int limit; /* available free range */
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unsigned int max_ctx; /* max. context value supported by all CPUs */
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/* call wrap_mmu_context when next >= max */
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unsigned long *bitmap; /* bitmap size is max_ctx+1 */
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unsigned long *flushmap;/* pending rid to be flushed */
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};
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extern struct ia64_ctx ia64_ctx;
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DECLARE_PER_CPU(u8, ia64_need_tlb_flush);
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extern void mmu_context_init (void);
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extern void wrap_mmu_context (struct mm_struct *mm);
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/*
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* When the context counter wraps around all TLBs need to be flushed because
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* an old context number might have been reused. This is signalled by the
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* ia64_need_tlb_flush per-CPU variable, which is checked in the routine
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* below. Called by activate_mm(). <efocht@ess.nec.de>
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*/
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static inline void
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delayed_tlb_flush (void)
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{
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extern void local_flush_tlb_all (void);
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unsigned long flags;
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if (unlikely(__ia64_per_cpu_var(ia64_need_tlb_flush))) {
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spin_lock_irqsave(&ia64_ctx.lock, flags);
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if (__ia64_per_cpu_var(ia64_need_tlb_flush)) {
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local_flush_tlb_all();
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__ia64_per_cpu_var(ia64_need_tlb_flush) = 0;
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}
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spin_unlock_irqrestore(&ia64_ctx.lock, flags);
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}
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}
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static inline nv_mm_context_t
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get_mmu_context (struct mm_struct *mm)
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{
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unsigned long flags;
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nv_mm_context_t context = mm->context;
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if (likely(context))
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goto out;
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spin_lock_irqsave(&ia64_ctx.lock, flags);
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/* re-check, now that we've got the lock: */
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context = mm->context;
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if (context == 0) {
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cpumask_clear(mm_cpumask(mm));
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if (ia64_ctx.next >= ia64_ctx.limit) {
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ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
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ia64_ctx.max_ctx, ia64_ctx.next);
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ia64_ctx.limit = find_next_bit(ia64_ctx.bitmap,
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ia64_ctx.max_ctx, ia64_ctx.next);
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if (ia64_ctx.next >= ia64_ctx.max_ctx)
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wrap_mmu_context(mm);
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}
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mm->context = context = ia64_ctx.next++;
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__set_bit(context, ia64_ctx.bitmap);
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}
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spin_unlock_irqrestore(&ia64_ctx.lock, flags);
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out:
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/*
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* Ensure we're not starting to use "context" before any old
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* uses of it are gone from our TLB.
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*/
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delayed_tlb_flush();
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return context;
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}
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/*
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* Initialize context number to some sane value. MM is guaranteed to be a
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* brand-new address-space, so no TLB flushing is needed, ever.
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*/
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#define init_new_context init_new_context
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static inline int
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init_new_context (struct task_struct *p, struct mm_struct *mm)
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{
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mm->context = 0;
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return 0;
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}
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static inline void
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reload_context (nv_mm_context_t context)
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{
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unsigned long rid;
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unsigned long rid_incr = 0;
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unsigned long rr0, rr1, rr2, rr3, rr4;
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#ifdef CONFIG_HUGETLB_PAGE
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unsigned long old_rr4;
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old_rr4 = ia64_get_rr(RGN_BASE(RGN_HPAGE));
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#endif
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rid = context << 3; /* make space for encoding the region number */
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rid_incr = 1 << 8;
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/* encode the region id, preferred page size, and VHPT enable bit: */
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rr0 = (rid << 8) | (PAGE_SHIFT << 2) | 1;
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rr1 = rr0 + 1*rid_incr;
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rr2 = rr0 + 2*rid_incr;
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rr3 = rr0 + 3*rid_incr;
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rr4 = rr0 + 4*rid_incr;
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#ifdef CONFIG_HUGETLB_PAGE
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rr4 = (rr4 & (~(0xfcUL))) | (old_rr4 & 0xfc);
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# if RGN_HPAGE != 4
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# error "reload_context assumes RGN_HPAGE is 4"
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# endif
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#endif
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ia64_set_rr0_to_rr4(rr0, rr1, rr2, rr3, rr4);
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ia64_srlz_i(); /* srlz.i implies srlz.d */
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}
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/*
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* Must be called with preemption off
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*/
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static inline void
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activate_context (struct mm_struct *mm)
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{
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nv_mm_context_t context;
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do {
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context = get_mmu_context(mm);
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if (!cpumask_test_cpu(smp_processor_id(), mm_cpumask(mm)))
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cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
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reload_context(context);
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/*
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* in the unlikely event of a TLB-flush by another thread,
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* redo the load.
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*/
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} while (unlikely(context != mm->context));
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}
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/*
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* Switch from address space PREV to address space NEXT.
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*/
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#define activate_mm activate_mm
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static inline void
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activate_mm (struct mm_struct *prev, struct mm_struct *next)
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{
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/*
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* We may get interrupts here, but that's OK because interrupt
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* handlers cannot touch user-space.
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*/
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ia64_set_kr(IA64_KR_PT_BASE, __pa(next->pgd));
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activate_context(next);
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}
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#define switch_mm(prev_mm,next_mm,next_task) activate_mm(prev_mm, next_mm)
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#include <asm-generic/mmu_context.h>
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# endif /* ! __ASSEMBLY__ */
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#endif /* _ASM_IA64_MMU_CONTEXT_H */
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