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         pr_debug("[tlbrange<%02lx,%08lx,%08lx>]\n",
  99                  (unsigned long)mm->context.asid[cpu], start, end);
 100         local_irq_save(flags);
 101
 102         if (end-start + (PAGE_SIZE-1) <= _TLB_ENTRIES << PAGE_SHIFT) {
 103                 int oldpid = get_rasid_register();
 104
 105                 set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
 106                 start &= PAGE_MASK;
 107                 if (vma->vm_flags & VM_EXEC)
 108                         while(start < end) {
 109                                 invalidate_itlb_mapping(start);
 110                                 invalidate_dtlb_mapping(start);
 111                                 start += PAGE_SIZE;
 112                         }
 113                 else
 114                         while(start < end) {
 115                                 invalidate_dtlb_mapping(start);
 116                                 start += PAGE_SIZE;
 117                         }
 118
 119                 set_rasid_register(oldpid);
 120         } else {
 121                 local_flush_tlb_mm(mm);
 122         }
 123         local_irq_restore(flags);
 124 }
 125
 126 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 127 {
 128         int cpu = smp_processor_id();
 129         struct mm_struct* mm = vma->vm_mm;
 130         unsigned long flags;
 131         int oldpid;
 132
 133         if (mm->context.asid[cpu] == NO_CONTEXT)
 134                 return;
 135
 136         local_irq_save(flags);
 137
 138         oldpid = get_rasid_register();
 139         set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
 140
 141         if (vma->vm_flags & VM_EXEC)
 142                 invalidate_itlb_mapping(page);
 143         invalidate_dtlb_mapping(page);
 144
 145         set_rasid_register(oldpid);
 146
 147         local_irq_restore(flags);
 148 }
 149
 150 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
 151 {
 152         if (end > start && start >= TASK_SIZE && end <= PAGE_OFFSET &&
 153             end - start < _TLB_ENTRIES << PAGE_SHIFT) {
 154                 start &= PAGE_MASK;
 155                 while (start < end) {
 156                         invalidate_itlb_mapping(start);
 157                         invalidate_dtlb_mapping(start);
 158                         start += PAGE_SIZE;
 159                 }
 160         } else {
 161                 local_flush_tlb_all();
 162         }
 163 }
 164
 165 void update_mmu_tlb(struct vm_area_struct *vma,
 166                     unsigned long address, pte_t *ptep)
 167 {
 168         local_flush_tlb_page(vma, address);
 169 }
 170
 171 #ifdef CONFIG_DEBUG_TLB_SANITY
 172
 173 static unsigned get_pte_for_vaddr(unsigned vaddr)
 174 {
 175         struct task_struct *task = get_current();
 176         struct mm_struct *mm = task->mm;
 177         pgd_t *pgd;
 178         p4d_t *p4d;
 179         pud_t *pud;
 180         pmd_t *pmd;
 181         pte_t *pte;
 182         unsigned int pteval;
 183
 184         if (!mm)
 185                 mm = task->active_mm;
 186         pgd = pgd_offset(mm, vaddr);
 187         if (pgd_none_or_clear_bad(pgd))
 188                 return 0;
 189         p4d = p4d_offset(pgd, vaddr);
 190         if (p4d_none_or_clear_bad(p4d))
 191                 return 0;
 192         pud = pud_offset(p4d, vaddr);
 193         if (pud_none_or_clear_bad(pud))
 194                 return 0;
 195         pmd = pmd_offset(pud, vaddr);
 196         if (pmd_none_or_clear_bad(pmd))
 197                 return 0;
 198         pte = pte_offset_map(pmd, vaddr);
 199         if (!pte)
 200                 return 0;
 201         pteval = pte_val(*pte);
 202         pte_unmap(pte);
 203         return pteval;
 204 }
 205
 206 enum {
 207         TLB_SUSPICIOUS  = 1,
 208         TLB_INSANE      = 2,
 209 };
 210
 211 static void tlb_insane(void)
 212 {
 213         BUG_ON(1);
 214 }
 215
 216 static void tlb_suspicious(void)
 217 {
 218         WARN_ON(1);
 219 }
 220
 221 /*
 222  * Check that TLB entries with kernel ASID (1) have kernel VMA (>= TASK_SIZE),
 223  * and TLB entries with user ASID (>=4) have VMA < TASK_SIZE.
 224  *
 225  * Check that valid TLB entries either have the same PA as the PTE, or PTE is
 226  * marked as non-present. Non-present PTE and the page with non-zero refcount
 227  * and zero mapcount is normal for batched TLB flush operation. Zero refcount
 228  * means that the page was freed prematurely. Non-zero mapcount is unusual,
 229  * but does not necessary means an error, thus marked as suspicious.
 230  */
 231 static int check_tlb_entry(unsigned w, unsigned e, bool dtlb)
 232 {
 233         unsigned tlbidx = w | (e << PAGE_SHIFT);
 234         unsigned r0 = dtlb ?
 235                 read_dtlb_virtual(tlbidx) : read_itlb_virtual(tlbidx);
 236         unsigned r1 = dtlb ?
 237                 read_dtlb_translation(tlbidx) : read_itlb_translation(tlbidx);
 238         unsigned vpn = (r0 & PAGE_MASK) | (e << PAGE_SHIFT);
 239         unsigned pte = get_pte_for_vaddr(vpn);
 240         unsigned mm_asid = (get_rasid_register() >> 8) & ASID_MASK;
 241         unsigned tlb_asid = r0 & ASID_MASK;
 242         bool kernel = tlb_asid == 1;
 243         int rc = 0;
 244
 245         if (tlb_asid > 0 && ((vpn < TASK_SIZE) == kernel)) {
 246                 pr_err("%cTLB: way: %u, entry: %u, VPN %08x in %s PTE\n",
 247                                 dtlb ? 'D' : 'I', w, e, vpn,
 248                                 kernel ? "kernel" : "user");
 249                 rc |= TLB_INSANE;
 250         }
 251
 252         if (tlb_asid == mm_asid) {
 253                 if ((pte ^ r1) & PAGE_MASK) {
 254                         pr_err("%cTLB: way: %u, entry: %u, mapping: %08x->%08x, PTE: %08x\n",
 255                                         dtlb ? 'D' : 'I', w, e, r0, r1, pte);
 256                         if (pte == 0 || !pte_present(__pte(pte))) {
 257                                 struct page *p = pfn_to_page(r1 >> PAGE_SHIFT);
 258                                 pr_err("page refcount: %d, mapcount: %d\n",
 259                                                 page_count(p),
 260                                                 page_mapcount(p));
 261                                 if (!page_count(p))
 262                                         rc |= TLB_INSANE;
 263                                 else if (page_mapcount(p))
 264                                         rc |= TLB_SUSPICIOUS;
 265                         } else {
 266                                 rc |= TLB_INSANE;
 267                         }
 268                 }
 269         }
 270         return rc;
 271 }
 272
 273 void check_tlb_sanity(void)
 274 {
 275         unsigned long flags;
 276         unsigned w, e;
 277         int bug = 0;
 278
 279         local_irq_save(flags);
 280         for (w = 0; w < DTLB_ARF_WAYS; ++w)
 281                 for (e = 0; e < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); ++e)
 282                         bug |= check_tlb_entry(w, e, true);
 283         for (w = 0; w < ITLB_ARF_WAYS; ++w)
 284                 for (e = 0; e < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); ++e)
 285                         bug |= check_tlb_entry(w, e, false);
 286         if (bug & TLB_INSANE)
 287                 tlb_insane();
 288         if (bug & TLB_SUSPICIOUS)
 289                 tlb_suspicious();
 290         local_irq_restore(flags);
 291 }
 292
 293 #endif /* CONFIG_DEBUG_TLB_SANITY */