arch/sh/mm/tlbflush_64.c

   1 /*
   2  * arch/sh/mm/tlb-flush_64.c
   3  *
   4  * Copyright (C) 2000, 2001  Paolo Alberelli
   5  * Copyright (C) 2003  Richard Curnow (/proc/tlb, bug fixes)
   6  * Copyright (C) 2003 - 2009 Paul Mundt
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12 #include <linux/signal.h>
  13 #include <linux/rwsem.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/string.h>
  18 #include <linux/types.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/mman.h>
  21 #include <linux/mm.h>
  22 #include <linux/smp.h>
  23 #include <linux/perf_event.h>
  24 #include <linux/interrupt.h>
  25 #include <asm/system.h>
  26 #include <asm/io.h>
  27 #include <asm/tlb.h>
  28 #include <asm/uaccess.h>
  29 #include <asm/pgalloc.h>
  30 #include <asm/mmu_context.h>
  31
  32 extern void die(const char *,struct pt_regs *,long);
  33
  34 #define PFLAG(val,flag)   (( (val) & (flag) ) ? #flag : "" )
  35 #define PPROT(flag) PFLAG(pgprot_val(prot),flag)
  36
  37 static inline void print_prots(pgprot_t prot)
  38 {
  39         printk("prot is 0x%016llx\n",pgprot_val(prot));
  40
  41         printk("%s %s %s %s %s\n",PPROT(_PAGE_SHARED),PPROT(_PAGE_READ),
  42                PPROT(_PAGE_EXECUTE),PPROT(_PAGE_WRITE),PPROT(_PAGE_USER));
  43 }
  44
  45 static inline void print_vma(struct vm_area_struct *vma)
  46 {
  47         printk("vma start 0x%08lx\n", vma->vm_start);
  48         printk("vma end   0x%08lx\n", vma->vm_end);
  49
  50         print_prots(vma->vm_page_prot);
  51         printk("vm_flags 0x%08lx\n", vma->vm_flags);
  52 }
  53
  54 static inline void print_task(struct task_struct *tsk)
  55 {
  56         printk("Task pid %d\n", task_pid_nr(tsk));
  57 }
  58
  59 static pte_t *lookup_pte(struct mm_struct *mm, unsigned long address)
  60 {
  61         pgd_t *dir;
  62         pud_t *pud;
  63         pmd_t *pmd;
  64         pte_t *pte;
  65         pte_t entry;
  66
  67         dir = pgd_offset(mm, address);
  68         if (pgd_none(*dir))
  69                 return NULL;
  70
  71         pud = pud_offset(dir, address);
  72         if (pud_none(*pud))
  73                 return NULL;
  74
  75         pmd = pmd_offset(pud, address);
  76         if (pmd_none(*pmd))
  77                 return NULL;
  78
  79         pte = pte_offset_kernel(pmd, address);
  80         entry = *pte;
  81         if (pte_none(entry) || !pte_present(entry))
  82                 return NULL;
  83
  84         return pte;
  85 }
  86
  87 /*
  88  * This routine handles page faults.  It determines the address,
  89  * and the problem, and then passes it off to one of the appropriate
  90  * routines.
  91  */
  92 asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
  93                               unsigned long textaccess, unsigned long address)
  94 {
  95         struct task_struct *tsk;
  96         struct mm_struct *mm;
  97         struct vm_area_struct * vma;
  98         const struct exception_table_entry *fixup;
  99         pte_t *pte;
 100         int fault;
 101
 102         /* SIM
 103          * Note this is now called with interrupts still disabled
 104          * This is to cope with being called for a missing IO port
 105          * address with interrupts disabled. This should be fixed as
 106          * soon as we have a better 'fast path' miss handler.
 107          *
 108          * Plus take care how you try and debug this stuff.
 109          * For example, writing debug data to a port which you
 110          * have just faulted on is not going to work.
 111          */
 112
 113         tsk = current;
 114         mm = tsk->mm;
 115
 116         /* Not an IO address, so reenable interrupts */
 117         local_irq_enable();
 118
 119         perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 120
 121         /*
 122          * If we're in an interrupt or have no user
 123          * context, we must not take the fault..
 124          */
 125         if (in_atomic() || !mm)
 126                 goto no_context;
 127
 128         /* TLB misses upon some cache flushes get done under cli() */
 129         down_read(&mm->mmap_sem);
 130
 131         vma = find_vma(mm, address);
 132
 133         if (!vma) {
 134 #ifdef DEBUG_FAULT
 135                 print_task(tsk);
 136                 printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
 137                        __func__, __LINE__,
 138                        address,regs->pc,textaccess,writeaccess);
 139                 show_regs(regs);
 140 #endif
 141                 goto bad_area;
 142         }
 143         if (vma->vm_start <= address) {
 144                 goto good_area;
 145         }
 146
 147         if (!(vma->vm_flags & VM_GROWSDOWN)) {
 148 #ifdef DEBUG_FAULT
 149                 print_task(tsk);
 150                 printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
 151                        __func__, __LINE__,
 152                        address,regs->pc,textaccess,writeaccess);
 153                 show_regs(regs);
 154
 155                 print_vma(vma);
 156 #endif
 157                 goto bad_area;
 158         }
 159         if (expand_stack(vma, address)) {
 160 #ifdef DEBUG_FAULT
 161                 print_task(tsk);
 162                 printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
 163                        __func__, __LINE__,
 164                        address,regs->pc,textaccess,writeaccess);
 165                 show_regs(regs);
 166 #endif
 167                 goto bad_area;
 168         }
 169 /*
 170  * Ok, we have a good vm_area for this memory access, so
 171  * we can handle it..
 172  */
 173 good_area:
 174         if (textaccess) {
 175                 if (!(vma->vm_flags & VM_EXEC))
 176                         goto bad_area;
 177         } else {
 178                 if (writeaccess) {
 179                         if (!(vma->vm_flags & VM_WRITE))
 180                                 goto bad_area;
 181                 } else {
 182                         if (!(vma->vm_flags & VM_READ))
 183                                 goto bad_area;
 184                 }
 185         }
 186
 187         /*
 188          * If for any reason at all we couldn't handle the fault,
 189          * make sure we exit gracefully rather than endlessly redo
 190          * the fault.
 191          */
 192         fault = handle_mm_fault(mm, vma, address, writeaccess ? FAULT_FLAG_WRITE : 0);
 193         if (unlikely(fault & VM_FAULT_ERROR)) {
 194                 if (fault & VM_FAULT_OOM)
 195                         goto out_of_memory;
 196                 else if (fault & VM_FAULT_SIGBUS)
 197                         goto do_sigbus;
 198                 BUG();
 199         }
 200
 201         if (fault & VM_FAULT_MAJOR) {
 202                 tsk->maj_flt++;
 203                 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
 204                                      regs, address);
 205         } else {
 206                 tsk->min_flt++;
 207                 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
 208                                      regs, address);
 209         }
 210
 211         /* If we get here, the page fault has been handled.  Do the TLB refill
 212            now from the newly-setup PTE, to avoid having to fault again right
 213            away on the same instruction. */
 214         pte = lookup_pte (mm, address);
 215         if (!pte) {
 216                 /* From empirical evidence, we can get here, due to
 217                    !pte_present(pte).  (e.g. if a swap-in occurs, and the page
 218                    is swapped back out again before the process that wanted it
 219                    gets rescheduled?) */
 220                 goto no_pte;
 221         }
 222
 223         __do_tlb_refill(address, textaccess, pte);
 224
 225 no_pte:
 226
 227         up_read(&mm->mmap_sem);
 228         return;
 229
 230 /*
 231  * Something tried to access memory that isn't in our memory map..
 232  * Fix it, but check if it's kernel or user first..
 233  */
 234 bad_area:
 235 #ifdef DEBUG_FAULT
 236         printk("fault:bad area\n");
 237 #endif
 238         up_read(&mm->mmap_sem);
 239
 240         if (user_mode(regs)) {
 241                 static int count=0;
 242                 siginfo_t info;
 243                 if (count < 4) {
 244                         /* This is really to help debug faults when starting
 245                          * usermode, so only need a few */
 246                         count++;
 247                         printk("user mode bad_area address=%08lx pid=%d (%s) pc=%08lx\n",
 248                                 address, task_pid_nr(current), current->comm,
 249                                 (unsigned long) regs->pc);
 250 #if 0
 251                         show_regs(regs);
 252 #endif
 253                 }
 254                 if (is_global_init(tsk)) {
 255                         panic("INIT had user mode bad_area\n");
 256                 }
 257                 tsk->thread.address = address;
 258                 tsk->thread.error_code = writeaccess;
 259                 info.si_signo = SIGSEGV;
 260                 info.si_errno = 0;
 261                 info.si_addr = (void *) address;
 262                 force_sig_info(SIGSEGV, &info, tsk);
 263                 return;
 264         }
 265
 266 no_context:
 267 #ifdef DEBUG_FAULT
 268         printk("fault:No context\n");
 269 #endif
 270         /* Are we prepared to handle this kernel fault?  */
 271         fixup = search_exception_tables(regs->pc);
 272         if (fixup) {
 273                 regs->pc = fixup->fixup;
 274                 return;
 275         }
 276
 277 /*
 278  * Oops. The kernel tried to access some bad page. We'll have to
 279  * terminate things with extreme prejudice.
 280  *
 281  */
 282         if (address < PAGE_SIZE)
 283                 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
 284         else
 285                 printk(KERN_ALERT "Unable to handle kernel paging request");
 286         printk(" at virtual address %08lx\n", address);
 287         printk(KERN_ALERT "pc = %08Lx%08Lx\n", regs->pc >> 32, regs->pc & 0xffffffff);
 288         die("Oops", regs, writeaccess);
 289         do_exit(SIGKILL);
 290
 291 /*
 292  * We ran out of memory, or some other thing happened to us that made
 293  * us unable to handle the page fault gracefully.
 294  */
 295 out_of_memory:
 296         up_read(&mm->mmap_sem);
 297         if (!user_mode(regs))
 298                 goto no_context;
 299         pagefault_out_of_memory();
 300         return;
 301
 302 do_sigbus:
 303         printk("fault:Do sigbus\n");
 304         up_read(&mm->mmap_sem);
 305
 306         /*
 307          * Send a sigbus, regardless of whether we were in kernel
 308          * or user mode.
 309          */
 310         tsk->thread.address = address;
 311         tsk->thread.error_code = writeaccess;
 312         tsk->thread.trap_no = 14;
 313         force_sig(SIGBUS, tsk);
 314
 315         /* Kernel mode? Handle exceptions or die */
 316         if (!user_mode(regs))
 317                 goto no_context;
 318 }
 319
 320 void local_flush_tlb_one(unsigned long asid, unsigned long page)
 321 {
 322         unsigned long long match, pteh=0, lpage;
 323         unsigned long tlb;
 324
 325         /*
 326          * Sign-extend based on neff.
 327          */
 328         lpage = neff_sign_extend(page);
 329         match = (asid << PTEH_ASID_SHIFT) | PTEH_VALID;
 330         match |= lpage;
 331
 332         for_each_itlb_entry(tlb) {
 333                 asm volatile ("getcfg   %1, 0, %0"
 334                               : "=r" (pteh)
 335                               : "r" (tlb) );
 336
 337                 if (pteh == match) {
 338                         __flush_tlb_slot(tlb);
 339                         break;
 340                 }
 341         }
 342
 343         for_each_dtlb_entry(tlb) {
 344                 asm volatile ("getcfg   %1, 0, %0"
 345                               : "=r" (pteh)
 346                               : "r" (tlb) );
 347
 348                 if (pteh == match) {
 349                         __flush_tlb_slot(tlb);
 350                         break;
 351                 }
 352
 353         }
 354 }
 355
 356 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 357 {
 358         unsigned long flags;
 359
 360         if (vma->vm_mm) {
 361                 page &= PAGE_MASK;
 362                 local_irq_save(flags);
 363                 local_flush_tlb_one(get_asid(), page);
 364                 local_irq_restore(flags);
 365         }
 366 }
 367
 368 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 369                            unsigned long end)
 370 {
 371         unsigned long flags;
 372         unsigned long long match, pteh=0, pteh_epn, pteh_low;
 373         unsigned long tlb;
 374         unsigned int cpu = smp_processor_id();
 375         struct mm_struct *mm;
 376
 377         mm = vma->vm_mm;
 378         if (cpu_context(cpu, mm) == NO_CONTEXT)
 379                 return;
 380
 381         local_irq_save(flags);
 382
 383         start &= PAGE_MASK;
 384         end &= PAGE_MASK;
 385
 386         match = (cpu_asid(cpu, mm) << PTEH_ASID_SHIFT) | PTEH_VALID;
 387
 388         /* Flush ITLB */
 389         for_each_itlb_entry(tlb) {
 390                 asm volatile ("getcfg   %1, 0, %0"
 391                               : "=r" (pteh)
 392                               : "r" (tlb) );
 393
 394                 pteh_epn = pteh & PAGE_MASK;
 395                 pteh_low = pteh & ~PAGE_MASK;
 396
 397                 if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
 398                         __flush_tlb_slot(tlb);
 399         }
 400
 401         /* Flush DTLB */
 402         for_each_dtlb_entry(tlb) {
 403                 asm volatile ("getcfg   %1, 0, %0"
 404                               : "=r" (pteh)
 405                               : "r" (tlb) );
 406
 407                 pteh_epn = pteh & PAGE_MASK;
 408                 pteh_low = pteh & ~PAGE_MASK;
 409
 410                 if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
 411                         __flush_tlb_slot(tlb);
 412         }
 413
 414         local_irq_restore(flags);
 415 }
 416
 417 void local_flush_tlb_mm(struct mm_struct *mm)
 418 {
 419         unsigned long flags;
 420         unsigned int cpu = smp_processor_id();
 421
 422         if (cpu_context(cpu, mm) == NO_CONTEXT)
 423                 return;
 424
 425         local_irq_save(flags);
 426
 427         cpu_context(cpu, mm) = NO_CONTEXT;
 428         if (mm == current->mm)
 429                 activate_context(mm, cpu);
 430
 431         local_irq_restore(flags);
 432 }
 433
 434 void local_flush_tlb_all(void)
 435 {
 436         /* Invalidate all, including shared pages, excluding fixed TLBs */
 437         unsigned long flags, tlb;
 438
 439         local_irq_save(flags);
 440
 441         /* Flush each ITLB entry */
 442         for_each_itlb_entry(tlb)
 443                 __flush_tlb_slot(tlb);
 444
 445         /* Flush each DTLB entry */
 446         for_each_dtlb_entry(tlb)
 447                 __flush_tlb_slot(tlb);
 448
 449         local_irq_restore(flags);
 450 }
 451
 452 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
 453 {
 454         /* FIXME: Optimize this later.. */
 455         flush_tlb_all();
 456 }
 457
 458 void __flush_tlb_global(void)
 459 {
 460         flush_tlb_all();
 461 }
 462
 463 void __update_tlb(struct vm_area_struct *vma, unsigned long address, pte_t pte)
 464 {
 465 }