arch/mn10300/mm/tlb-smp.c

   1 /* SMP TLB support routines.
   2  *
   3  * Copyright (C) 2006-2008 Panasonic Corporation
   4  * All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * version 2 as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  */
  15 #include <linux/interrupt.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/init.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/cpumask.h>
  20 #include <linux/err.h>
  21 #include <linux/kernel.h>
  22 #include <linux/delay.h>
  23 #include <linux/sched.h>
  24 #include <linux/profile.h>
  25 #include <linux/smp.h>
  26 #include <asm/tlbflush.h>
  27 #include <asm/bitops.h>
  28 #include <asm/processor.h>
  29 #include <asm/bug.h>
  30 #include <asm/exceptions.h>
  31 #include <asm/hardirq.h>
  32 #include <asm/fpu.h>
  33 #include <asm/mmu_context.h>
  34 #include <asm/thread_info.h>
  35 #include <asm/cpu-regs.h>
  36 #include <asm/intctl-regs.h>
  37
  38 /*
  39  * For flush TLB
  40  */
  41 #define FLUSH_ALL       0xffffffff
  42
  43 static cpumask_t flush_cpumask;
  44 static struct mm_struct *flush_mm;
  45 static unsigned long flush_va;
  46 static DEFINE_SPINLOCK(tlbstate_lock);
  47
  48 DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
  49         &init_mm, 0
  50 };
  51
  52 static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
  53                              unsigned long va);
  54 static void do_flush_tlb_all(void *info);
  55
  56 /**
  57  * smp_flush_tlb - Callback to invalidate the TLB.
  58  * @unused: Callback context (ignored).
  59  */
  60 void smp_flush_tlb(void *unused)
  61 {
  62         unsigned long cpu_id;
  63
  64         cpu_id = get_cpu();
  65
  66         if (!cpumask_test_cpu(cpu_id, &flush_cpumask))
  67                 /* This was a BUG() but until someone can quote me the line
  68                  * from the intel manual that guarantees an IPI to multiple
  69                  * CPUs is retried _only_ on the erroring CPUs its staying as a
  70                  * return
  71                  *
  72                  * BUG();
  73                  */
  74                 goto out;
  75
  76         if (flush_va == FLUSH_ALL)
  77                 local_flush_tlb();
  78         else
  79                 local_flush_tlb_page(flush_mm, flush_va);
  80
  81         smp_mb__before_clear_bit();
  82         cpumask_clear_cpu(cpu_id, &flush_cpumask);
  83         smp_mb__after_clear_bit();
  84 out:
  85         put_cpu();
  86 }
  87
  88 /**
  89  * flush_tlb_others - Tell the specified CPUs to invalidate their TLBs
  90  * @cpumask: The list of CPUs to target.
  91  * @mm: The VM context to flush from (if va!=FLUSH_ALL).
  92  * @va: Virtual address to flush or FLUSH_ALL to flush everything.
  93  */
  94 static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
  95                              unsigned long va)
  96 {
  97         cpumask_t tmp;
  98
  99         /* A couple of sanity checks (to be removed):
 100          * - mask must not be empty
 101          * - current CPU must not be in mask
 102          * - we do not send IPIs to as-yet unbooted CPUs.
 103          */
 104         BUG_ON(!mm);
 105         BUG_ON(cpumask_empty(&cpumask));
 106         BUG_ON(cpumask_test_cpu(smp_processor_id(), &cpumask));
 107
 108         cpumask_and(&tmp, &cpumask, cpu_online_mask);
 109         BUG_ON(!cpumask_equal(&cpumask, &tmp));
 110
 111         /* I'm not happy about this global shared spinlock in the MM hot path,
 112          * but we'll see how contended it is.
 113          *
 114          * Temporarily this turns IRQs off, so that lockups are detected by the
 115          * NMI watchdog.
 116          */
 117         spin_lock(&tlbstate_lock);
 118
 119         flush_mm = mm;
 120         flush_va = va;
 121 #if NR_CPUS <= BITS_PER_LONG
 122         atomic_set_mask(cpumask.bits[0], &flush_cpumask.bits[0]);
 123 #else
 124 #error Not supported.
 125 #endif
 126
 127         /* FIXME: if NR_CPUS>=3, change send_IPI_mask */
 128         smp_call_function(smp_flush_tlb, NULL, 1);
 129
 130         while (!cpumask_empty(&flush_cpumask))
 131                 /* Lockup detection does not belong here */
 132                 smp_mb();
 133
 134         flush_mm = NULL;
 135         flush_va = 0;
 136         spin_unlock(&tlbstate_lock);
 137 }
 138
 139 /**
 140  * flush_tlb_mm - Invalidate TLB of specified VM context
 141  * @mm: The VM context to invalidate.
 142  */
 143 void flush_tlb_mm(struct mm_struct *mm)
 144 {
 145         cpumask_t cpu_mask;
 146
 147         preempt_disable();
 148         cpumask_copy(&cpu_mask, mm_cpumask(mm));
 149         cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
 150
 151         local_flush_tlb();
 152         if (!cpumask_empty(&cpu_mask))
 153                 flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
 154
 155         preempt_enable();
 156 }
 157
 158 /**
 159  * flush_tlb_current_task - Invalidate TLB of current task
 160  */
 161 void flush_tlb_current_task(void)
 162 {
 163         struct mm_struct *mm = current->mm;
 164         cpumask_t cpu_mask;
 165
 166         preempt_disable();
 167         cpumask_copy(&cpu_mask, mm_cpumask(mm));
 168         cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
 169
 170         local_flush_tlb();
 171         if (!cpumask_empty(&cpu_mask))
 172                 flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
 173
 174         preempt_enable();
 175 }
 176
 177 /**
 178  * flush_tlb_page - Invalidate TLB of page
 179  * @vma: The VM context to invalidate the page for.
 180  * @va: The virtual address of the page to invalidate.
 181  */
 182 void flush_tlb_page(struct vm_area_struct *vma, unsigned long va)
 183 {
 184         struct mm_struct *mm = vma->vm_mm;
 185         cpumask_t cpu_mask;
 186
 187         preempt_disable();
 188         cpumask_copy(&cpu_mask, mm_cpumask(mm));
 189         cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
 190
 191         local_flush_tlb_page(mm, va);
 192         if (!cpumask_empty(&cpu_mask))
 193                 flush_tlb_others(cpu_mask, mm, va);
 194
 195         preempt_enable();
 196 }
 197
 198 /**
 199  * do_flush_tlb_all - Callback to completely invalidate a TLB
 200  * @unused: Callback context (ignored).
 201  */
 202 static void do_flush_tlb_all(void *unused)
 203 {
 204         local_flush_tlb_all();
 205 }
 206
 207 /**
 208  * flush_tlb_all - Completely invalidate TLBs on all CPUs
 209  */
 210 void flush_tlb_all(void)
 211 {
 212         on_each_cpu(do_flush_tlb_all, 0, 1);
 213 }