arch/ia64/mm/tlb.c

   1 /*
   2  * TLB support routines.
   3  *
   4  * Copyright (C) 1998-2001, 2003 Hewlett-Packard Co
   5  *      David Mosberger-Tang <davidm@hpl.hp.com>
   6  *
   7  * 08/02/00 A. Mallick <asit.k.mallick@intel.com>
   8  *              Modified RID allocation for SMP
   9  *          Goutham Rao <goutham.rao@intel.com>
  10  *              IPI based ptc implementation and A-step IPI implementation.
  11  * Rohit Seth <rohit.seth@intel.com>
  12  * Ken Chen <kenneth.w.chen@intel.com>
  13  */
  14 #include <linux/config.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/kernel.h>
  18 #include <linux/sched.h>
  19 #include <linux/smp.h>
  20 #include <linux/mm.h>
  21 #include <linux/bootmem.h>
  22
  23 #include <asm/delay.h>
  24 #include <asm/mmu_context.h>
  25 #include <asm/pgalloc.h>
  26 #include <asm/pal.h>
  27 #include <asm/tlbflush.h>
  28 #include <asm/dma.h>
  29
  30 static struct {
  31         unsigned long mask;     /* mask of supported purge page-sizes */
  32         unsigned long max_bits; /* log2 of largest supported purge page-size */
  33 } purge;
  34
  35 struct ia64_ctx ia64_ctx = {
  36         .lock =         SPIN_LOCK_UNLOCKED,
  37         .next =         1,
  38         .max_ctx =      ~0U
  39 };
  40
  41 DEFINE_PER_CPU(u8, ia64_need_tlb_flush);
  42
  43 /*
  44  * Initializes the ia64_ctx.bitmap array based on max_ctx+1.
  45  * Called after cpu_init() has setup ia64_ctx.max_ctx based on
  46  * maximum RID that is supported by boot CPU.
  47  */
  48 void __init
  49 mmu_context_init (void)
  50 {
  51         ia64_ctx.bitmap = alloc_bootmem((ia64_ctx.max_ctx+1)>>3);
  52         ia64_ctx.flushmap = alloc_bootmem((ia64_ctx.max_ctx+1)>>3);
  53 }
  54
  55 /*
  56  * Acquire the ia64_ctx.lock before calling this function!
  57  */
  58 void
  59 wrap_mmu_context (struct mm_struct *mm)
  60 {
  61         int i, cpu;
  62         unsigned long flush_bit;
  63
  64         for (i=0; i <= ia64_ctx.max_ctx / BITS_PER_LONG; i++) {
  65                 flush_bit = xchg(&ia64_ctx.flushmap[i], 0);
  66                 ia64_ctx.bitmap[i] ^= flush_bit;
  67         }
  68
  69         /* use offset at 300 to skip daemons */
  70         ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
  71                                 ia64_ctx.max_ctx, 300);
  72         ia64_ctx.limit = find_next_bit(ia64_ctx.bitmap,
  73                                 ia64_ctx.max_ctx, ia64_ctx.next);
  74
  75         /*
  76          * can't call flush_tlb_all() here because of race condition
  77          * with O(1) scheduler [EF]
  78          */
  79         cpu = get_cpu(); /* prevent preemption/migration */
  80         for_each_online_cpu(i)
  81                 if (i != cpu)
  82                         per_cpu(ia64_need_tlb_flush, i) = 1;
  83         put_cpu();
  84         local_flush_tlb_all();
  85 }
  86
  87 void
  88 ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
  89                        unsigned long end, unsigned long nbits)
  90 {
  91         static DEFINE_SPINLOCK(ptcg_lock);
  92
  93         if (mm != current->active_mm) {
  94                 flush_tlb_all();
  95                 return;
  96         }
  97
  98         /* HW requires global serialization of ptc.ga.  */
  99         spin_lock(&ptcg_lock);
 100         {
 101                 do {
 102                         /*
 103                          * Flush ALAT entries also.
 104                          */
 105                         ia64_ptcga(start, (nbits<<2));
 106                         ia64_srlz_i();
 107                         start += (1UL << nbits);
 108                 } while (start < end);
 109         }
 110         spin_unlock(&ptcg_lock);
 111 }
 112
 113 void
 114 local_flush_tlb_all (void)
 115 {
 116         unsigned long i, j, flags, count0, count1, stride0, stride1, addr;
 117
 118         addr    = local_cpu_data->ptce_base;
 119         count0  = local_cpu_data->ptce_count[0];
 120         count1  = local_cpu_data->ptce_count[1];
 121         stride0 = local_cpu_data->ptce_stride[0];
 122         stride1 = local_cpu_data->ptce_stride[1];
 123
 124         local_irq_save(flags);
 125         for (i = 0; i < count0; ++i) {
 126                 for (j = 0; j < count1; ++j) {
 127                         ia64_ptce(addr);
 128                         addr += stride1;
 129                 }
 130                 addr += stride0;
 131         }
 132         local_irq_restore(flags);
 133         ia64_srlz_i();                  /* srlz.i implies srlz.d */
 134 }
 135
 136 void
 137 flush_tlb_range (struct vm_area_struct *vma, unsigned long start,
 138                  unsigned long end)
 139 {
 140         struct mm_struct *mm = vma->vm_mm;
 141         unsigned long size = end - start;
 142         unsigned long nbits;
 143
 144 #ifndef CONFIG_SMP
 145         if (mm != current->active_mm) {
 146                 mm->context = 0;
 147                 return;
 148         }
 149 #endif
 150
 151         nbits = ia64_fls(size + 0xfff);
 152         while (unlikely (((1UL << nbits) & purge.mask) == 0) &&
 153                         (nbits < purge.max_bits))
 154                 ++nbits;
 155         if (nbits > purge.max_bits)
 156                 nbits = purge.max_bits;
 157         start &= ~((1UL << nbits) - 1);
 158
 159 # ifdef CONFIG_SMP
 160         platform_global_tlb_purge(mm, start, end, nbits);
 161 # else
 162         preempt_disable();
 163         do {
 164                 ia64_ptcl(start, (nbits<<2));
 165                 start += (1UL << nbits);
 166         } while (start < end);
 167         preempt_enable();
 168 # endif
 169
 170         ia64_srlz_i();                  /* srlz.i implies srlz.d */
 171 }
 172 EXPORT_SYMBOL(flush_tlb_range);
 173
 174 void __devinit
 175 ia64_tlb_init (void)
 176 {
 177         ia64_ptce_info_t ptce_info;
 178         unsigned long tr_pgbits;
 179         long status;
 180
 181         if ((status = ia64_pal_vm_page_size(&tr_pgbits, &purge.mask)) != 0) {
 182                 printk(KERN_ERR "PAL_VM_PAGE_SIZE failed with status=%ld;"
 183                        "defaulting to architected purge page-sizes.\n", status);
 184                 purge.mask = 0x115557000UL;
 185         }
 186         purge.max_bits = ia64_fls(purge.mask);
 187
 188         ia64_get_ptce(&ptce_info);
 189         local_cpu_data->ptce_base = ptce_info.base;
 190         local_cpu_data->ptce_count[0] = ptce_info.count[0];
 191         local_cpu_data->ptce_count[1] = ptce_info.count[1];
 192         local_cpu_data->ptce_stride[0] = ptce_info.stride[0];
 193         local_cpu_data->ptce_stride[1] = ptce_info.stride[1];
 194
 195         local_flush_tlb_all();  /* nuke left overs from bootstrapping... */
 196 }