arch/sh/mm/fault.c

   1 /* $Id: fault.c,v 1.14 2004/01/13 05:52:11 kkojima Exp $
   2  *
   3  *  linux/arch/sh/mm/fault.c
   4  *  Copyright (C) 1999  Niibe Yutaka
   5  *  Copyright (C) 2003  Paul Mundt
   6  *
   7  *  Based on linux/arch/i386/mm/fault.c:
   8  *   Copyright (C) 1995  Linus Torvalds
   9  */
  10
  11 #include <linux/signal.h>
  12 #include <linux/sched.h>
  13 #include <linux/kernel.h>
  14 #include <linux/errno.h>
  15 #include <linux/string.h>
  16 #include <linux/types.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/mman.h>
  19 #include <linux/mm.h>
  20 #include <linux/smp.h>
  21 #include <linux/smp_lock.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/module.h>
  24
  25 #include <asm/system.h>
  26 #include <asm/io.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/pgalloc.h>
  29 #include <asm/hardirq.h>
  30 #include <asm/mmu_context.h>
  31 #include <asm/cacheflush.h>
  32 #include <asm/kgdb.h>
  33
  34 extern void die(const char *,struct pt_regs *,long);
  35
  36 /*
  37  * This routine handles page faults.  It determines the address,
  38  * and the problem, and then passes it off to one of the appropriate
  39  * routines.
  40  */
  41 asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
  42                               unsigned long address)
  43 {
  44         struct task_struct *tsk;
  45         struct mm_struct *mm;
  46         struct vm_area_struct * vma;
  47         unsigned long page;
  48
  49 #ifdef CONFIG_SH_KGDB
  50         if (kgdb_nofault && kgdb_bus_err_hook)
  51                 kgdb_bus_err_hook();
  52 #endif
  53
  54         tsk = current;
  55         mm = tsk->mm;
  56
  57         /*
  58          * If we're in an interrupt or have no user
  59          * context, we must not take the fault..
  60          */
  61         if (in_atomic() || !mm)
  62                 goto no_context;
  63
  64         down_read(&mm->mmap_sem);
  65
  66         vma = find_vma(mm, address);
  67         if (!vma)
  68                 goto bad_area;
  69         if (vma->vm_start <= address)
  70                 goto good_area;
  71         if (!(vma->vm_flags & VM_GROWSDOWN))
  72                 goto bad_area;
  73         if (expand_stack(vma, address))
  74                 goto bad_area;
  75 /*
  76  * Ok, we have a good vm_area for this memory access, so
  77  * we can handle it..
  78  */
  79 good_area:
  80         if (writeaccess) {
  81                 if (!(vma->vm_flags & VM_WRITE))
  82                         goto bad_area;
  83         } else {
  84                 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
  85                         goto bad_area;
  86         }
  87
  88         /*
  89          * If for any reason at all we couldn't handle the fault,
  90          * make sure we exit gracefully rather than endlessly redo
  91          * the fault.
  92          */
  93 survive:
  94         switch (handle_mm_fault(mm, vma, address, writeaccess)) {
  95                 case VM_FAULT_MINOR:
  96                         tsk->min_flt++;
  97                         break;
  98                 case VM_FAULT_MAJOR:
  99                         tsk->maj_flt++;
 100                         break;
 101                 case VM_FAULT_SIGBUS:
 102                         goto do_sigbus;
 103                 case VM_FAULT_OOM:
 104                         goto out_of_memory;
 105                 default:
 106                         BUG();
 107         }
 108
 109         up_read(&mm->mmap_sem);
 110         return;
 111
 112 /*
 113  * Something tried to access memory that isn't in our memory map..
 114  * Fix it, but check if it's kernel or user first..
 115  */
 116 bad_area:
 117         up_read(&mm->mmap_sem);
 118
 119         if (user_mode(regs)) {
 120                 tsk->thread.address = address;
 121                 tsk->thread.error_code = writeaccess;
 122                 force_sig(SIGSEGV, tsk);
 123                 return;
 124         }
 125
 126 no_context:
 127         /* Are we prepared to handle this kernel fault?  */
 128         if (fixup_exception(regs))
 129                 return;
 130
 131 /*
 132  * Oops. The kernel tried to access some bad page. We'll have to
 133  * terminate things with extreme prejudice.
 134  *
 135  */
 136         if (address < PAGE_SIZE)
 137                 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
 138         else
 139                 printk(KERN_ALERT "Unable to handle kernel paging request");
 140         printk(" at virtual address %08lx\n", address);
 141         printk(KERN_ALERT "pc = %08lx\n", regs->pc);
 142         asm volatile("mov.l     %1, %0"
 143                      : "=r" (page)
 144                      : "m" (__m(MMU_TTB)));
 145         if (page) {
 146                 page = ((unsigned long *) page)[address >> 22];
 147                 printk(KERN_ALERT "*pde = %08lx\n", page);
 148                 if (page & _PAGE_PRESENT) {
 149                         page &= PAGE_MASK;
 150                         address &= 0x003ff000;
 151                         page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
 152                         printk(KERN_ALERT "*pte = %08lx\n", page);
 153                 }
 154         }
 155         die("Oops", regs, writeaccess);
 156         do_exit(SIGKILL);
 157
 158 /*
 159  * We ran out of memory, or some other thing happened to us that made
 160  * us unable to handle the page fault gracefully.
 161  */
 162 out_of_memory:
 163         up_read(&mm->mmap_sem);
 164         if (current->pid == 1) {
 165                 yield();
 166                 down_read(&mm->mmap_sem);
 167                 goto survive;
 168         }
 169         printk("VM: killing process %s\n", tsk->comm);
 170         if (user_mode(regs))
 171                 do_exit(SIGKILL);
 172         goto no_context;
 173
 174 do_sigbus:
 175         up_read(&mm->mmap_sem);
 176
 177         /*
 178          * Send a sigbus, regardless of whether we were in kernel
 179          * or user mode.
 180          */
 181         tsk->thread.address = address;
 182         tsk->thread.error_code = writeaccess;
 183         tsk->thread.trap_no = 14;
 184         force_sig(SIGBUS, tsk);
 185
 186         /* Kernel mode? Handle exceptions or die */
 187         if (!user_mode(regs))
 188                 goto no_context;
 189 }
 190
 191 /*
 192  * Called with interrupt disabled.
 193  */
 194 asmlinkage int __do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
 195                                unsigned long address)
 196 {
 197         unsigned long addrmax = P4SEG;
 198         pgd_t *dir;
 199         pmd_t *pmd;
 200         pte_t *pte;
 201         pte_t entry;
 202
 203 #ifdef CONFIG_SH_KGDB
 204         if (kgdb_nofault && kgdb_bus_err_hook)
 205                 kgdb_bus_err_hook();
 206 #endif
 207
 208 #ifdef CONFIG_SH_STORE_QUEUES
 209         addrmax = P4SEG_STORE_QUE + 0x04000000;
 210 #endif
 211
 212         if (address >= P3SEG && address < addrmax)
 213                 dir = pgd_offset_k(address);
 214         else if (address >= TASK_SIZE)
 215                 return 1;
 216         else if (!current->mm)
 217                 return 1;
 218         else
 219                 dir = pgd_offset(current->mm, address);
 220
 221         pmd = pmd_offset(dir, address);
 222         if (pmd_none(*pmd))
 223                 return 1;
 224         if (pmd_bad(*pmd)) {
 225                 pmd_ERROR(*pmd);
 226                 pmd_clear(pmd);
 227                 return 1;
 228         }
 229         pte = pte_offset_kernel(pmd, address);
 230         entry = *pte;
 231         if (pte_none(entry) || pte_not_present(entry)
 232             || (writeaccess && !pte_write(entry)))
 233                 return 1;
 234
 235         if (writeaccess)
 236                 entry = pte_mkdirty(entry);
 237         entry = pte_mkyoung(entry);
 238
 239 #ifdef CONFIG_CPU_SH4
 240         /*
 241          * ITLB is not affected by "ldtlb" instruction.
 242          * So, we need to flush the entry by ourselves.
 243          */
 244
 245         {
 246                 unsigned long flags;
 247                 local_irq_save(flags);
 248                 __flush_tlb_page(get_asid(), address&PAGE_MASK);
 249                 local_irq_restore(flags);
 250         }
 251 #endif
 252
 253         set_pte(pte, entry);
 254         update_mmu_cache(NULL, address, entry);
 255
 256         return 0;
 257 }
 258
 259 void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 260 {
 261         if (vma->vm_mm && vma->vm_mm->context != NO_CONTEXT) {
 262                 unsigned long flags;
 263                 unsigned long asid;
 264                 unsigned long saved_asid = MMU_NO_ASID;
 265
 266                 asid = vma->vm_mm->context & MMU_CONTEXT_ASID_MASK;
 267                 page &= PAGE_MASK;
 268
 269                 local_irq_save(flags);
 270                 if (vma->vm_mm != current->mm) {
 271                         saved_asid = get_asid();
 272                         set_asid(asid);
 273                 }
 274                 __flush_tlb_page(asid, page);
 275                 if (saved_asid != MMU_NO_ASID)
 276                         set_asid(saved_asid);
 277                 local_irq_restore(flags);
 278         }
 279 }
 280
 281 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 282                      unsigned long end)
 283 {
 284         struct mm_struct *mm = vma->vm_mm;
 285
 286         if (mm->context != NO_CONTEXT) {
 287                 unsigned long flags;
 288                 int size;
 289
 290                 local_irq_save(flags);
 291                 size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 292                 if (size > (MMU_NTLB_ENTRIES/4)) { /* Too many TLB to flush */
 293                         mm->context = NO_CONTEXT;
 294                         if (mm == current->mm)
 295                                 activate_context(mm);
 296                 } else {
 297                         unsigned long asid = mm->context&MMU_CONTEXT_ASID_MASK;
 298                         unsigned long saved_asid = MMU_NO_ASID;
 299
 300                         start &= PAGE_MASK;
 301                         end += (PAGE_SIZE - 1);
 302                         end &= PAGE_MASK;
 303                         if (mm != current->mm) {
 304                                 saved_asid = get_asid();
 305                                 set_asid(asid);
 306                         }
 307                         while (start < end) {
 308                                 __flush_tlb_page(asid, start);
 309                                 start += PAGE_SIZE;
 310                         }
 311                         if (saved_asid != MMU_NO_ASID)
 312                                 set_asid(saved_asid);
 313                 }
 314                 local_irq_restore(flags);
 315         }
 316 }
 317
 318 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 319 {
 320         unsigned long flags;
 321         int size;
 322
 323         local_irq_save(flags);
 324         size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 325         if (size > (MMU_NTLB_ENTRIES/4)) { /* Too many TLB to flush */
 326                 flush_tlb_all();
 327         } else {
 328                 unsigned long asid = init_mm.context&MMU_CONTEXT_ASID_MASK;
 329                 unsigned long saved_asid = get_asid();
 330
 331                 start &= PAGE_MASK;
 332                 end += (PAGE_SIZE - 1);
 333                 end &= PAGE_MASK;
 334                 set_asid(asid);
 335                 while (start < end) {
 336                         __flush_tlb_page(asid, start);
 337                         start += PAGE_SIZE;
 338                 }
 339                 set_asid(saved_asid);
 340         }
 341         local_irq_restore(flags);
 342 }
 343
 344 void flush_tlb_mm(struct mm_struct *mm)
 345 {
 346         /* Invalidate all TLB of this process. */
 347         /* Instead of invalidating each TLB, we get new MMU context. */
 348         if (mm->context != NO_CONTEXT) {
 349                 unsigned long flags;
 350
 351                 local_irq_save(flags);
 352                 mm->context = NO_CONTEXT;
 353                 if (mm == current->mm)
 354                         activate_context(mm);
 355                 local_irq_restore(flags);
 356         }
 357 }
 358
 359 void flush_tlb_all(void)
 360 {
 361         unsigned long flags, status;
 362
 363         /*
 364          * Flush all the TLB.
 365          *
 366          * Write to the MMU control register's bit:
 367          *      TF-bit for SH-3, TI-bit for SH-4.
 368          *      It's same position, bit #2.
 369          */
 370         local_irq_save(flags);
 371         status = ctrl_inl(MMUCR);
 372         status |= 0x04;
 373         ctrl_outl(status, MMUCR);
 374         local_irq_restore(flags);
 375 }