arch/ia64/include/asm/tlb.h

   1 #ifndef _ASM_IA64_TLB_H
   2 #define _ASM_IA64_TLB_H
   3 /*
   4  * Based on <asm-generic/tlb.h>.
   5  *
   6  * Copyright (C) 2002-2003 Hewlett-Packard Co
   7  *      David Mosberger-Tang <davidm@hpl.hp.com>
   8  */
   9 /*
  10  * Removing a translation from a page table (including TLB-shootdown) is a four-step
  11  * procedure:
  12  *
  13  *      (1) Flush (virtual) caches --- ensures virtual memory is coherent with kernel memory
  14  *          (this is a no-op on ia64).
  15  *      (2) Clear the relevant portions of the page-table
  16  *      (3) Flush the TLBs --- ensures that stale content is gone from CPU TLBs
  17  *      (4) Release the pages that were freed up in step (2).
  18  *
  19  * Note that the ordering of these steps is crucial to avoid races on MP machines.
  20  *
  21  * The Linux kernel defines several platform-specific hooks for TLB-shootdown.  When
  22  * unmapping a portion of the virtual address space, these hooks are called according to
  23  * the following template:
  24  *
  25  *      tlb <- tlb_gather_mmu(mm, start, end);          // start unmap for address space MM
  26  *      {
  27  *        for each vma that needs a shootdown do {
  28  *          tlb_start_vma(tlb, vma);
  29  *            for each page-table-entry PTE that needs to be removed do {
  30  *              tlb_remove_tlb_entry(tlb, pte, address);
  31  *              if (pte refers to a normal page) {
  32  *                tlb_remove_page(tlb, page);
  33  *              }
  34  *            }
  35  *          tlb_end_vma(tlb, vma);
  36  *        }
  37  *      }
  38  *      tlb_finish_mmu(tlb, start, end);        // finish unmap for address space MM
  39  */
  40 #include <linux/mm.h>
  41 #include <linux/pagemap.h>
  42 #include <linux/swap.h>
  43
  44 #include <asm/pgalloc.h>
  45 #include <asm/processor.h>
  46 #include <asm/tlbflush.h>
  47 #include <asm/machvec.h>
  48
  49 /*
  50  * If we can't allocate a page to make a big batch of page pointers
  51  * to work on, then just handle a few from the on-stack structure.
  52  */
  53 #define IA64_GATHER_BUNDLE      8
  54
  55 struct mmu_gather {
  56         struct mm_struct        *mm;
  57         unsigned int            nr;
  58         unsigned int            max;
  59         unsigned char           fullmm;         /* non-zero means full mm flush */
  60         unsigned char           need_flush;     /* really unmapped some PTEs? */
  61         unsigned long           start, end;
  62         unsigned long           start_addr;
  63         unsigned long           end_addr;
  64         struct page             **pages;
  65         struct page             *local[IA64_GATHER_BUNDLE];
  66 };
  67
  68 struct ia64_tr_entry {
  69         u64 ifa;
  70         u64 itir;
  71         u64 pte;
  72         u64 rr;
  73 }; /*Record for tr entry!*/
  74
  75 extern int ia64_itr_entry(u64 target_mask, u64 va, u64 pte, u64 log_size);
  76 extern void ia64_ptr_entry(u64 target_mask, int slot);
  77
  78 extern struct ia64_tr_entry *ia64_idtrs[NR_CPUS];
  79
  80 /*
  81  region register macros
  82 */
  83 #define RR_TO_VE(val)   (((val) >> 0) & 0x0000000000000001)
  84 #define RR_VE(val)      (((val) & 0x0000000000000001) << 0)
  85 #define RR_VE_MASK      0x0000000000000001L
  86 #define RR_VE_SHIFT     0
  87 #define RR_TO_PS(val)   (((val) >> 2) & 0x000000000000003f)
  88 #define RR_PS(val)      (((val) & 0x000000000000003f) << 2)
  89 #define RR_PS_MASK      0x00000000000000fcL
  90 #define RR_PS_SHIFT     2
  91 #define RR_RID_MASK     0x00000000ffffff00L
  92 #define RR_TO_RID(val)  ((val >> 8) & 0xffffff)
  93
  94 /*
  95  * Flush the TLB for address range START to END and, if not in fast mode, release the
  96  * freed pages that where gathered up to this point.
  97  */
  98 static inline void
  99 ia64_tlb_flush_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end)
 100 {
 101         unsigned long i;
 102         unsigned int nr;
 103
 104         if (!tlb->need_flush)
 105                 return;
 106         tlb->need_flush = 0;
 107
 108         if (tlb->fullmm) {
 109                 /*
 110                  * Tearing down the entire address space.  This happens both as a result
 111                  * of exit() and execve().  The latter case necessitates the call to
 112                  * flush_tlb_mm() here.
 113                  */
 114                 flush_tlb_mm(tlb->mm);
 115         } else if (unlikely (end - start >= 1024*1024*1024*1024UL
 116                              || REGION_NUMBER(start) != REGION_NUMBER(end - 1)))
 117         {
 118                 /*
 119                  * If we flush more than a tera-byte or across regions, we're probably
 120                  * better off just flushing the entire TLB(s).  This should be very rare
 121                  * and is not worth optimizing for.
 122                  */
 123                 flush_tlb_all();
 124         } else {
 125                 /*
 126                  * XXX fix me: flush_tlb_range() should take an mm pointer instead of a
 127                  * vma pointer.
 128                  */
 129                 struct vm_area_struct vma;
 130
 131                 vma.vm_mm = tlb->mm;
 132                 /* flush the address range from the tlb: */
 133                 flush_tlb_range(&vma, start, end);
 134                 /* now flush the virt. page-table area mapping the address range: */
 135                 flush_tlb_range(&vma, ia64_thash(start), ia64_thash(end));
 136         }
 137
 138         /* lastly, release the freed pages */
 139         nr = tlb->nr;
 140
 141         tlb->nr = 0;
 142         tlb->start_addr = ~0UL;
 143         for (i = 0; i < nr; ++i)
 144                 free_page_and_swap_cache(tlb->pages[i]);
 145 }
 146
 147 static inline void __tlb_alloc_page(struct mmu_gather *tlb)
 148 {
 149         unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
 150
 151         if (addr) {
 152                 tlb->pages = (void *)addr;
 153                 tlb->max = PAGE_SIZE / sizeof(void *);
 154         }
 155 }
 156
 157
 158 static inline void
 159 tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
 160 {
 161         tlb->mm = mm;
 162         tlb->max = ARRAY_SIZE(tlb->local);
 163         tlb->pages = tlb->local;
 164         tlb->nr = 0;
 165         tlb->fullmm = !(start | (end+1));
 166         tlb->start = start;
 167         tlb->end = end;
 168         tlb->start_addr = ~0UL;
 169 }
 170
 171 /*
 172  * Called at the end of the shootdown operation to free up any resources that were
 173  * collected.
 174  */
 175 static inline void
 176 tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
 177 {
 178         /*
 179          * Note: tlb->nr may be 0 at this point, so we can't rely on tlb->start_addr and
 180          * tlb->end_addr.
 181          */
 182         ia64_tlb_flush_mmu(tlb, start, end);
 183
 184         /* keep the page table cache within bounds */
 185         check_pgt_cache();
 186
 187         if (tlb->pages != tlb->local)
 188                 free_pages((unsigned long)tlb->pages, 0);
 189 }
 190
 191 /*
 192  * Logically, this routine frees PAGE.  On MP machines, the actual freeing of the page
 193  * must be delayed until after the TLB has been flushed (see comments at the beginning of
 194  * this file).
 195  */
 196 static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
 197 {
 198         tlb->need_flush = 1;
 199
 200         if (!tlb->nr && tlb->pages == tlb->local)
 201                 __tlb_alloc_page(tlb);
 202
 203         tlb->pages[tlb->nr++] = page;
 204         VM_BUG_ON(tlb->nr > tlb->max);
 205
 206         return tlb->max - tlb->nr;
 207 }
 208
 209 static inline void tlb_flush_mmu(struct mmu_gather *tlb)
 210 {
 211         ia64_tlb_flush_mmu(tlb, tlb->start_addr, tlb->end_addr);
 212 }
 213
 214 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
 215 {
 216         if (!__tlb_remove_page(tlb, page))
 217                 tlb_flush_mmu(tlb);
 218 }
 219
 220 /*
 221  * Remove TLB entry for PTE mapped at virtual address ADDRESS.  This is called for any
 222  * PTE, not just those pointing to (normal) physical memory.
 223  */
 224 static inline void
 225 __tlb_remove_tlb_entry (struct mmu_gather *tlb, pte_t *ptep, unsigned long address)
 226 {
 227         if (tlb->start_addr == ~0UL)
 228                 tlb->start_addr = address;
 229         tlb->end_addr = address + PAGE_SIZE;
 230 }
 231
 232 #define tlb_migrate_finish(mm)  platform_tlb_migrate_finish(mm)
 233
 234 #define tlb_start_vma(tlb, vma)                 do { } while (0)
 235 #define tlb_end_vma(tlb, vma)                   do { } while (0)
 236
 237 #define tlb_remove_tlb_entry(tlb, ptep, addr)           \
 238 do {                                                    \
 239         tlb->need_flush = 1;                            \
 240         __tlb_remove_tlb_entry(tlb, ptep, addr);        \
 241 } while (0)
 242
 243 #define pte_free_tlb(tlb, ptep, address)                \
 244 do {                                                    \
 245         tlb->need_flush = 1;                            \
 246         __pte_free_tlb(tlb, ptep, address);             \
 247 } while (0)
 248
 249 #define pmd_free_tlb(tlb, ptep, address)                \
 250 do {                                                    \
 251         tlb->need_flush = 1;                            \
 252         __pmd_free_tlb(tlb, ptep, address);             \
 253 } while (0)
 254
 255 #define pud_free_tlb(tlb, pudp, address)                \
 256 do {                                                    \
 257         tlb->need_flush = 1;                            \
 258         __pud_free_tlb(tlb, pudp, address);             \
 259 } while (0)
 260
 261 #endif /* _ASM_IA64_TLB_H */