arch/powerpc/mm/tlb_nohash.c

   1 /*
   2  * This file contains the routines for TLB flushing.
   3  * On machines where the MMU does not use a hash table to store virtual to
   4  * physical translations (ie, SW loaded TLBs or Book3E compilant processors,
   5  * this does -not- include 603 however which shares the implementation with
   6  * hash based processors)
   7  *
   8  *  -- BenH
   9  *
  10  * Copyright 2008 Ben Herrenschmidt <benh@kernel.crashing.org>
  11  *                IBM Corp.
  12  *
  13  *  Derived from arch/ppc/mm/init.c:
  14  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  15  *
  16  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  17  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  18  *    Copyright (C) 1996 Paul Mackerras
  19  *
  20  *  Derived from "arch/i386/mm/init.c"
  21  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  22  *
  23  *  This program is free software; you can redistribute it and/or
  24  *  modify it under the terms of the GNU General Public License
  25  *  as published by the Free Software Foundation; either version
  26  *  2 of the License, or (at your option) any later version.
  27  *
  28  */
  29
  30 #include <linux/kernel.h>
  31 #include <linux/mm.h>
  32 #include <linux/init.h>
  33 #include <linux/highmem.h>
  34 #include <linux/pagemap.h>
  35 #include <linux/preempt.h>
  36 #include <linux/spinlock.h>
  37
  38 #include <asm/tlbflush.h>
  39 #include <asm/tlb.h>
  40
  41 #include "mmu_decl.h"
  42
  43 /*
  44  * Base TLB flushing operations:
  45  *
  46  *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
  47  *  - flush_tlb_page(vma, vmaddr) flushes one page
  48  *  - flush_tlb_range(vma, start, end) flushes a range of pages
  49  *  - flush_tlb_kernel_range(start, end) flushes kernel pages
  50  *
  51  *  - local_* variants of page and mm only apply to the current
  52  *    processor
  53  */
  54
  55 /*
  56  * These are the base non-SMP variants of page and mm flushing
  57  */
  58 void local_flush_tlb_mm(struct mm_struct *mm)
  59 {
  60         unsigned int pid;
  61
  62         preempt_disable();
  63         pid = mm->context.id;
  64         if (pid != MMU_NO_CONTEXT)
  65                 _tlbil_pid(pid);
  66         preempt_enable();
  67 }
  68 EXPORT_SYMBOL(local_flush_tlb_mm);
  69
  70 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
  71 {
  72         unsigned int pid;
  73
  74         preempt_disable();
  75         pid = vma ? vma->vm_mm->context.id : 0;
  76         if (pid != MMU_NO_CONTEXT)
  77                 _tlbil_va(vmaddr, pid);
  78         preempt_enable();
  79 }
  80 EXPORT_SYMBOL(local_flush_tlb_page);
  81
  82
  83 /*
  84  * And here are the SMP non-local implementations
  85  */
  86 #ifdef CONFIG_SMP
  87
  88 static DEFINE_SPINLOCK(tlbivax_lock);
  89
  90 struct tlb_flush_param {
  91         unsigned long addr;
  92         unsigned int pid;
  93 };
  94
  95 static void do_flush_tlb_mm_ipi(void *param)
  96 {
  97         struct tlb_flush_param *p = param;
  98
  99         _tlbil_pid(p ? p->pid : 0);
 100 }
 101
 102 static void do_flush_tlb_page_ipi(void *param)
 103 {
 104         struct tlb_flush_param *p = param;
 105
 106         _tlbil_va(p->addr, p->pid);
 107 }
 108
 109
 110 /* Note on invalidations and PID:
 111  *
 112  * We snapshot the PID with preempt disabled. At this point, it can still
 113  * change either because:
 114  * - our context is being stolen (PID -> NO_CONTEXT) on another CPU
 115  * - we are invaliating some target that isn't currently running here
 116  *   and is concurrently acquiring a new PID on another CPU
 117  * - some other CPU is re-acquiring a lost PID for this mm
 118  * etc...
 119  *
 120  * However, this shouldn't be a problem as we only guarantee
 121  * invalidation of TLB entries present prior to this call, so we
 122  * don't care about the PID changing, and invalidating a stale PID
 123  * is generally harmless.
 124  */
 125
 126 void flush_tlb_mm(struct mm_struct *mm)
 127 {
 128         cpumask_t cpu_mask;
 129         unsigned int pid;
 130
 131         preempt_disable();
 132         pid = mm->context.id;
 133         if (unlikely(pid == MMU_NO_CONTEXT))
 134                 goto no_context;
 135         cpu_mask = mm->cpu_vm_mask;
 136         cpu_clear(smp_processor_id(), cpu_mask);
 137         if (!cpus_empty(cpu_mask)) {
 138                 struct tlb_flush_param p = { .pid = pid };
 139                 smp_call_function_mask(cpu_mask, do_flush_tlb_mm_ipi, &p, 1);
 140         }
 141         _tlbil_pid(pid);
 142  no_context:
 143         preempt_enable();
 144 }
 145 EXPORT_SYMBOL(flush_tlb_mm);
 146
 147 void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
 148 {
 149         cpumask_t cpu_mask;
 150         unsigned int pid;
 151
 152         preempt_disable();
 153         pid = vma ? vma->vm_mm->context.id : 0;
 154         if (unlikely(pid == MMU_NO_CONTEXT))
 155                 goto bail;
 156         cpu_mask = vma->vm_mm->cpu_vm_mask;
 157         cpu_clear(smp_processor_id(), cpu_mask);
 158         if (!cpus_empty(cpu_mask)) {
 159                 /* If broadcast tlbivax is supported, use it */
 160                 if (mmu_has_feature(MMU_FTR_USE_TLBIVAX_BCAST)) {
 161                         int lock = mmu_has_feature(MMU_FTR_LOCK_BCAST_INVAL);
 162                         if (lock)
 163                                 spin_lock(&tlbivax_lock);
 164                         _tlbivax_bcast(vmaddr, pid);
 165                         if (lock)
 166                                 spin_unlock(&tlbivax_lock);
 167                         goto bail;
 168                 } else {
 169                         struct tlb_flush_param p = { .pid = pid, .addr = vmaddr };
 170                         smp_call_function_mask(cpu_mask,
 171                                                do_flush_tlb_page_ipi, &p, 1);
 172                 }
 173         }
 174         _tlbil_va(vmaddr, pid);
 175  bail:
 176         preempt_enable();
 177 }
 178 EXPORT_SYMBOL(flush_tlb_page);
 179
 180 #endif /* CONFIG_SMP */
 181
 182 /*
 183  * Flush kernel TLB entries in the given range
 184  */
 185 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 186 {
 187 #ifdef CONFIG_SMP
 188         preempt_disable();
 189         smp_call_function(do_flush_tlb_mm_ipi, NULL, 1);
 190         _tlbil_pid(0);
 191         preempt_enable();
 192 #else
 193         _tlbil_pid(0);
 194 #endif
 195 }
 196 EXPORT_SYMBOL(flush_tlb_kernel_range);
 197
 198 /*
 199  * Currently, for range flushing, we just do a full mm flush. This should
 200  * be optimized based on a threshold on the size of the range, since
 201  * some implementation can stack multiple tlbivax before a tlbsync but
 202  * for now, we keep it that way
 203  */
 204 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 205                      unsigned long end)
 206
 207 {
 208         flush_tlb_mm(vma->vm_mm);
 209 }
 210 EXPORT_SYMBOL(flush_tlb_range);