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/* SMP TLB support routines.
*
* Copyright (C) 2006-2008 Panasonic Corporation
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/profile.h>
#include <linux/smp.h>
#include <asm/tlbflush.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/processor.h>
#include <asm/bug.h>
#include <asm/exceptions.h>
#include <asm/hardirq.h>
#include <asm/fpu.h>
#include <asm/mmu_context.h>
#include <asm/thread_info.h>
#include <asm/cpu-regs.h>
#include <asm/intctl-regs.h>
/*
* For flush TLB
*/
#define FLUSH_ALL 0xffffffff
static cpumask_t flush_cpumask;
static struct mm_struct *flush_mm;
static unsigned long flush_va;
static DEFINE_SPINLOCK(tlbstate_lock);
DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
&init_mm, 0
};
static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
unsigned long va);
static void do_flush_tlb_all(void *info);
/**
* smp_flush_tlb - Callback to invalidate the TLB.
* @unused: Callback context (ignored).
*/
void smp_flush_tlb(void *unused)
{
unsigned long cpu_id;
cpu_id = get_cpu();
if (!cpumask_test_cpu(cpu_id, &flush_cpumask))
/* This was a BUG() but until someone can quote me the line
* from the intel manual that guarantees an IPI to multiple
* CPUs is retried _only_ on the erroring CPUs its staying as a
* return
*
* BUG();
*/
goto out;
if (flush_va == FLUSH_ALL)
local_flush_tlb();
else
local_flush_tlb_page(flush_mm, flush_va);
smp_mb__before_clear_bit();
cpumask_clear_cpu(cpu_id, &flush_cpumask);
smp_mb__after_clear_bit();
out:
put_cpu();
}
/**
* flush_tlb_others - Tell the specified CPUs to invalidate their TLBs
* @cpumask: The list of CPUs to target.
* @mm: The VM context to flush from (if va!=FLUSH_ALL).
* @va: Virtual address to flush or FLUSH_ALL to flush everything.
*/
static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
unsigned long va)
{
cpumask_t tmp;
/* A couple of sanity checks (to be removed):
* - mask must not be empty
* - current CPU must not be in mask
* - we do not send IPIs to as-yet unbooted CPUs.
*/
BUG_ON(!mm);
BUG_ON(cpumask_empty(&cpumask));
BUG_ON(cpumask_test_cpu(smp_processor_id(), &cpumask));
cpumask_and(&tmp, &cpumask, cpu_online_mask);
BUG_ON(!cpumask_equal(&cpumask, &tmp));
/* I'm not happy about this global shared spinlock in the MM hot path,
* but we'll see how contended it is.
*
* Temporarily this turns IRQs off, so that lockups are detected by the
* NMI watchdog.
*/
spin_lock(&tlbstate_lock);
flush_mm = mm;
flush_va = va;
#if NR_CPUS <= BITS_PER_LONG
atomic_set_mask(cpumask.bits[0], &flush_cpumask.bits[0]);
#else
#error Not supported.
#endif
/* FIXME: if NR_CPUS>=3, change send_IPI_mask */
smp_call_function(smp_flush_tlb, NULL, 1);
while (!cpumask_empty(&flush_cpumask))
/* Lockup detection does not belong here */
smp_mb();
flush_mm = NULL;
flush_va = 0;
spin_unlock(&tlbstate_lock);
}
/**
* flush_tlb_mm - Invalidate TLB of specified VM context
* @mm: The VM context to invalidate.
*/
void flush_tlb_mm(struct mm_struct *mm)
{
cpumask_t cpu_mask;
preempt_disable();
cpumask_copy(&cpu_mask, mm_cpumask(mm));
cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
local_flush_tlb();
if (!cpumask_empty(&cpu_mask))
flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
preempt_enable();
}
/**
* flush_tlb_current_task - Invalidate TLB of current task
*/
void flush_tlb_current_task(void)
{
struct mm_struct *mm = current->mm;
cpumask_t cpu_mask;
preempt_disable();
cpumask_copy(&cpu_mask, mm_cpumask(mm));
cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
local_flush_tlb();
if (!cpumask_empty(&cpu_mask))
flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
preempt_enable();
}
/**
* flush_tlb_page - Invalidate TLB of page
* @vma: The VM context to invalidate the page for.
* @va: The virtual address of the page to invalidate.
*/
void flush_tlb_page(struct vm_area_struct *vma, unsigned long va)
{
struct mm_struct *mm = vma->vm_mm;
cpumask_t cpu_mask;
preempt_disable();
cpumask_copy(&cpu_mask, mm_cpumask(mm));
cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
local_flush_tlb_page(mm, va);
if (!cpumask_empty(&cpu_mask))
flush_tlb_others(cpu_mask, mm, va);
preempt_enable();
}
/**
* do_flush_tlb_all - Callback to completely invalidate a TLB
* @unused: Callback context (ignored).
*/
static void do_flush_tlb_all(void *unused)
{
local_flush_tlb_all();
}
/**
* flush_tlb_all - Completely invalidate TLBs on all CPUs
*/
void flush_tlb_all(void)
{
on_each_cpu(do_flush_tlb_all, 0, 1);
}
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