* Authors: Bjorn Wesen
*
* $Log: fault.c,v $
+ * Revision 1.20 2005/03/04 08:16:18 starvik
+ * Merge of Linux 2.6.11.
+ *
+ * Revision 1.19 2005/01/14 10:07:59 starvik
+ * Fixed warning.
+ *
+ * Revision 1.18 2005/01/12 08:10:14 starvik
+ * Readded the change of frametype when handling kernel page fault fixup
+ * for v10. This is necessary to avoid that the CPU remakes the faulting
+ * access.
+ *
+ * Revision 1.17 2005/01/11 13:53:05 starvik
+ * Use raw_printk.
+ *
+ * Revision 1.16 2004/12/17 11:39:41 starvik
+ * SMP support.
+ *
+ * Revision 1.15 2004/11/23 18:36:18 starvik
+ * Stack is now non-executable.
+ * Signal handler trampolines are placed in a reserved page mapped into all
+ * processes.
+ *
+ * Revision 1.14 2004/11/23 07:10:21 starvik
+ * Moved find_fixup_code to generic code.
+ *
+ * Revision 1.13 2004/11/23 07:00:54 starvik
+ * Actually use the execute permission bit in the MMU. This makes it possible
+ * to prevent e.g. attacks where executable code is put on the stack.
+ *
+ * Revision 1.12 2004/09/29 06:16:04 starvik
+ * Use instruction_pointer
+ *
* Revision 1.11 2004/05/14 07:58:05 starvik
* Merge of changes from 2.4
*
extern int find_fixup_code(struct pt_regs *);
extern void die_if_kernel(const char *, struct pt_regs *, long);
+extern int raw_printk(const char *fmt, ...);
/* debug of low-level TLB reload */
#undef DEBUG
/* current active page directory */
-volatile pgd_t *current_pgd;
+volatile DEFINE_PER_CPU(pgd_t *,current_pgd);
+unsigned long cris_signal_return_page;
/*
* This routine handles page faults. It determines the address,
struct vm_area_struct * vma;
siginfo_t info;
- D(printk("Page fault for %X at %X, prot %d write %d\n",
- address, regs->erp, protection, writeaccess));
+ D(printk("Page fault for %lX on %X at %lX, prot %d write %d\n",
+ address, smp_processor_id(), instruction_pointer(regs),
+ protection, writeaccess));
tsk = current;
!user_mode(regs))
goto vmalloc_fault;
+ /* When stack execution is not allowed we store the signal
+ * trampolines in the reserved cris_signal_return_page.
+ * Handle this in the exact same way as vmalloc (we know
+ * that the mapping is there and is valid so no need to
+ * call handle_mm_fault).
+ */
+ if (cris_signal_return_page &&
+ address == cris_signal_return_page &&
+ !protection && user_mode(regs))
+ goto vmalloc_fault;
+
/* we can and should enable interrupts at this point */
- sti();
+ local_irq_enable();
mm = tsk->mm;
info.si_code = SEGV_MAPERR;
/* first do some preliminary protection checks */
- if (writeaccess) {
+ if (writeaccess == 2){
+ if (!(vma->vm_flags & VM_EXEC))
+ goto bad_area;
+ } else if (writeaccess == 1) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
} else {
* the fault.
*/
- switch (handle_mm_fault(mm, vma, address, writeaccess)) {
- case 1:
+ switch (handle_mm_fault(mm, vma, address, writeaccess & 1)) {
+ case VM_FAULT_MINOR:
tsk->min_flt++;
break;
- case 2:
+ case VM_FAULT_MAJOR:
tsk->maj_flt++;
break;
- case 0:
+ case VM_FAULT_SIGBUS:
goto do_sigbus;
default:
goto out_of_memory;
*/
if ((unsigned long) (address) < PAGE_SIZE)
- printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
+ raw_printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
else
- printk(KERN_ALERT "Unable to handle kernel access");
- printk(" at virtual address %08lx\n",address);
+ raw_printk(KERN_ALERT "Unable to handle kernel access");
+ raw_printk(" at virtual address %08lx\n",address);
die_if_kernel("Oops", regs, (writeaccess << 1) | protection);
int offset = pgd_index(address);
pgd_t *pgd, *pgd_k;
+ pud_t *pud, *pud_k;
pmd_t *pmd, *pmd_k;
pte_t *pte_k;
- pgd = (pgd_t *)current_pgd + offset;
+ pgd = (pgd_t *)per_cpu(current_pgd, smp_processor_id()) + offset;
pgd_k = init_mm.pgd + offset;
/* Since we're two-level, we don't need to do both
* it exists.
*/
- pmd = pmd_offset(pgd, address);
- pmd_k = pmd_offset(pgd_k, address);
+ pud = pud_offset(pgd, address);
+ pud_k = pud_offset(pgd_k, address);
+ if (!pud_present(*pud_k))
+ goto no_context;
+
+ pmd = pmd_offset(pud, address);
+ pmd_k = pmd_offset(pud_k, address);
if (!pmd_present(*pmd_k))
goto bad_area_nosemaphore;
return;
}
}
+
+/* Find fixup code. */
+int
+find_fixup_code(struct pt_regs *regs)
+{
+ const struct exception_table_entry *fixup;
+
+ if ((fixup = search_exception_tables(instruction_pointer(regs))) != 0) {
+ /* Adjust the instruction pointer in the stackframe. */
+ instruction_pointer(regs) = fixup->fixup;
+ arch_fixup(regs);
+ return 1;
+ }
+
+ return 0;
+}
git://git.onelab.eu / linux-2.6.git / blobdiff