arch/xtensa/mm/tlb.c

   1 /*
   2  * arch/xtensa/mm/tlb.c
   3  *
   4  * Logic that manipulates the Xtensa MMU.  Derived from MIPS.
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  *
  10  * Copyright (C) 2001 - 2003 Tensilica Inc.
  11  *
  12  * Joe Taylor
  13  * Chris Zankel <chris@zankel.net>
  14  * Marc Gauthier
  15  */
  16
  17 #include <linux/mm.h>
  18 #include <asm/processor.h>
  19 #include <asm/mmu_context.h>
  20 #include <asm/tlbflush.h>
  21 #include <asm/cacheflush.h>
  22
  23
  24 static inline void __flush_itlb_all (void)
  25 {
  26         int w, i;
  27
  28         for (w = 0; w < ITLB_ARF_WAYS; w++) {
  29                 for (i = 0; i < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); i++) {
  30                         int e = w + (i << PAGE_SHIFT);
  31                         invalidate_itlb_entry_no_isync(e);
  32                 }
  33         }
  34         asm volatile ("isync\n");
  35 }
  36
  37 static inline void __flush_dtlb_all (void)
  38 {
  39         int w, i;
  40
  41         for (w = 0; w < DTLB_ARF_WAYS; w++) {
  42                 for (i = 0; i < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); i++) {
  43                         int e = w + (i << PAGE_SHIFT);
  44                         invalidate_dtlb_entry_no_isync(e);
  45                 }
  46         }
  47         asm volatile ("isync\n");
  48 }
  49
  50
  51 void local_flush_tlb_all(void)
  52 {
  53         __flush_itlb_all();
  54         __flush_dtlb_all();
  55 }
  56
  57 /* If mm is current, we simply assign the current task a new ASID, thus,
  58  * invalidating all previous tlb entries. If mm is someone else's user mapping,
  59  * wie invalidate the context, thus, when that user mapping is swapped in,
  60  * a new context will be assigned to it.
  61  */
  62
  63 void local_flush_tlb_mm(struct mm_struct *mm)
  64 {
  65         int cpu = smp_processor_id();
  66
  67         if (mm == current->active_mm) {
  68                 unsigned long flags;
  69                 local_irq_save(flags);
  70                 mm->context.asid[cpu] = NO_CONTEXT;
  71                 activate_context(mm, cpu);
  72                 local_irq_restore(flags);
  73         } else {
  74                 mm->context.asid[cpu] = NO_CONTEXT;
  75                 mm->context.cpu = -1;
  76         }
  77 }
  78
  79
  80 #define _ITLB_ENTRIES (ITLB_ARF_WAYS << XCHAL_ITLB_ARF_ENTRIES_LOG2)
  81 #define _DTLB_ENTRIES (DTLB_ARF_WAYS << XCHAL_DTLB_ARF_ENTRIES_LOG2)
  82 #if _ITLB_ENTRIES > _DTLB_ENTRIES
  83 # define _TLB_ENTRIES _ITLB_ENTRIES
  84 #else
  85 # define _TLB_ENTRIES _DTLB_ENTRIES
  86 #endif
  87
  88 void local_flush_tlb_range(struct vm_area_struct *vma,
  89                 unsigned long start, unsigned long end)
  90 {
  91         int cpu = smp_processor_id();
  92         struct mm_struct *mm = vma->vm_mm;
  93         unsigned long flags;
  94
  95         if (mm->context.asid[cpu] == NO_CONTEXT)
  96                 return;
  97
  98 #if 0
  99         printk("[tlbrange<%02lx,%08lx,%08lx>]\n",
 100                         (unsigned long)mm->context.asid[cpu], start, end);
 101 #endif
 102         local_irq_save(flags);
 103
 104         if (end-start + (PAGE_SIZE-1) <= _TLB_ENTRIES << PAGE_SHIFT) {
 105                 int oldpid = get_rasid_register();
 106
 107                 set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
 108                 start &= PAGE_MASK;
 109                 if (vma->vm_flags & VM_EXEC)
 110                         while(start < end) {
 111                                 invalidate_itlb_mapping(start);
 112                                 invalidate_dtlb_mapping(start);
 113                                 start += PAGE_SIZE;
 114                         }
 115                 else
 116                         while(start < end) {
 117                                 invalidate_dtlb_mapping(start);
 118                                 start += PAGE_SIZE;
 119                         }
 120
 121                 set_rasid_register(oldpid);
 122         } else {
 123                 local_flush_tlb_mm(mm);
 124         }
 125         local_irq_restore(flags);
 126 }
 127
 128 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 129 {
 130         int cpu = smp_processor_id();
 131         struct mm_struct* mm = vma->vm_mm;
 132         unsigned long flags;
 133         int oldpid;
 134
 135         if (mm->context.asid[cpu] == NO_CONTEXT)
 136                 return;
 137
 138         local_irq_save(flags);
 139
 140         oldpid = get_rasid_register();
 141         set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
 142
 143         if (vma->vm_flags & VM_EXEC)
 144                 invalidate_itlb_mapping(page);
 145         invalidate_dtlb_mapping(page);
 146
 147         set_rasid_register(oldpid);
 148
 149         local_irq_restore(flags);
 150 }
 151
 152 #ifdef CONFIG_DEBUG_TLB_SANITY
 153
 154 static unsigned get_pte_for_vaddr(unsigned vaddr)
 155 {
 156         struct task_struct *task = get_current();
 157         struct mm_struct *mm = task->mm;
 158         pgd_t *pgd;
 159         pmd_t *pmd;
 160         pte_t *pte;
 161
 162         if (!mm)
 163                 mm = task->active_mm;
 164         pgd = pgd_offset(mm, vaddr);
 165         if (pgd_none_or_clear_bad(pgd))
 166                 return 0;
 167         pmd = pmd_offset(pgd, vaddr);
 168         if (pmd_none_or_clear_bad(pmd))
 169                 return 0;
 170         pte = pte_offset_map(pmd, vaddr);
 171         if (!pte)
 172                 return 0;
 173         return pte_val(*pte);
 174 }
 175
 176 enum {
 177         TLB_SUSPICIOUS  = 1,
 178         TLB_INSANE      = 2,
 179 };
 180
 181 static void tlb_insane(void)
 182 {
 183         BUG_ON(1);
 184 }
 185
 186 static void tlb_suspicious(void)
 187 {
 188         WARN_ON(1);
 189 }
 190
 191 /*
 192  * Check that TLB entries with kernel ASID (1) have kernel VMA (>= TASK_SIZE),
 193  * and TLB entries with user ASID (>=4) have VMA < TASK_SIZE.
 194  *
 195  * Check that valid TLB entries either have the same PA as the PTE, or PTE is
 196  * marked as non-present. Non-present PTE and the page with non-zero refcount
 197  * and zero mapcount is normal for batched TLB flush operation. Zero refcount
 198  * means that the page was freed prematurely. Non-zero mapcount is unusual,
 199  * but does not necessary means an error, thus marked as suspicious.
 200  */
 201 static int check_tlb_entry(unsigned w, unsigned e, bool dtlb)
 202 {
 203         unsigned tlbidx = w | (e << PAGE_SHIFT);
 204         unsigned r0 = dtlb ?
 205                 read_dtlb_virtual(tlbidx) : read_itlb_virtual(tlbidx);
 206         unsigned vpn = (r0 & PAGE_MASK) | (e << PAGE_SHIFT);
 207         unsigned pte = get_pte_for_vaddr(vpn);
 208         unsigned mm_asid = (get_rasid_register() >> 8) & ASID_MASK;
 209         unsigned tlb_asid = r0 & ASID_MASK;
 210         bool kernel = tlb_asid == 1;
 211         int rc = 0;
 212
 213         if (tlb_asid > 0 && ((vpn < TASK_SIZE) == kernel)) {
 214                 pr_err("%cTLB: way: %u, entry: %u, VPN %08x in %s PTE\n",
 215                                 dtlb ? 'D' : 'I', w, e, vpn,
 216                                 kernel ? "kernel" : "user");
 217                 rc |= TLB_INSANE;
 218         }
 219
 220         if (tlb_asid == mm_asid) {
 221                 unsigned r1 = dtlb ? read_dtlb_translation(tlbidx) :
 222                         read_itlb_translation(tlbidx);
 223                 if ((pte ^ r1) & PAGE_MASK) {
 224                         pr_err("%cTLB: way: %u, entry: %u, mapping: %08x->%08x, PTE: %08x\n",
 225                                         dtlb ? 'D' : 'I', w, e, r0, r1, pte);
 226                         if (pte == 0 || !pte_present(__pte(pte))) {
 227                                 struct page *p = pfn_to_page(r1 >> PAGE_SHIFT);
 228                                 pr_err("page refcount: %d, mapcount: %d\n",
 229                                                 page_count(p),
 230                                                 page_mapcount(p));
 231                                 if (!page_count(p))
 232                                         rc |= TLB_INSANE;
 233                                 else if (page_mapped(p))
 234                                         rc |= TLB_SUSPICIOUS;
 235                         } else {
 236                                 rc |= TLB_INSANE;
 237                         }
 238                 }
 239         }
 240         return rc;
 241 }
 242
 243 void check_tlb_sanity(void)
 244 {
 245         unsigned long flags;
 246         unsigned w, e;
 247         int bug = 0;
 248
 249         local_irq_save(flags);
 250         for (w = 0; w < DTLB_ARF_WAYS; ++w)
 251                 for (e = 0; e < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); ++e)
 252                         bug |= check_tlb_entry(w, e, true);
 253         for (w = 0; w < ITLB_ARF_WAYS; ++w)
 254                 for (e = 0; e < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); ++e)
 255                         bug |= check_tlb_entry(w, e, false);
 256         if (bug & TLB_INSANE)
 257                 tlb_insane();
 258         if (bug & TLB_SUSPICIOUS)
 259                 tlb_suspicious();
 260         local_irq_restore(flags);
 261 }
 262
 263 #endif /* CONFIG_DEBUG_TLB_SANITY */