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-rw-r--r--arch/ia64/mm/fault.c261
1 files changed, 261 insertions, 0 deletions
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
new file mode 100644
index 000000000000..da859125aaef
--- /dev/null
+++ b/arch/ia64/mm/fault.c
@@ -0,0 +1,261 @@
+/*
+ * MMU fault handling support.
+ *
+ * Copyright (C) 1998-2002 Hewlett-Packard Co
+ * David Mosberger-Tang <davidm@hpl.hp.com>
+ */
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+extern void die (char *, struct pt_regs *, long);
+
+/*
+ * This routine is analogous to expand_stack() but instead grows the
+ * register backing store (which grows towards higher addresses).
+ * Since the register backing store is access sequentially, we
+ * disallow growing the RBS by more than a page at a time. Note that
+ * the VM_GROWSUP flag can be set on any VM area but that's fine
+ * because the total process size is still limited by RLIMIT_STACK and
+ * RLIMIT_AS.
+ */
+static inline long
+expand_backing_store (struct vm_area_struct *vma, unsigned long address)
+{
+ unsigned long grow;
+
+ grow = PAGE_SIZE >> PAGE_SHIFT;
+ if (address - vma->vm_start > current->signal->rlim[RLIMIT_STACK].rlim_cur
+ || (((vma->vm_mm->total_vm + grow) << PAGE_SHIFT) > current->signal->rlim[RLIMIT_AS].rlim_cur))
+ return -ENOMEM;
+ vma->vm_end += PAGE_SIZE;
+ vma->vm_mm->total_vm += grow;
+ if (vma->vm_flags & VM_LOCKED)
+ vma->vm_mm->locked_vm += grow;
+ __vm_stat_account(vma->vm_mm, vma->vm_flags, vma->vm_file, grow);
+ return 0;
+}
+
+/*
+ * Return TRUE if ADDRESS points at a page in the kernel's mapped segment
+ * (inside region 5, on ia64) and that page is present.
+ */
+static int
+mapped_kernel_page_is_present (unsigned long address)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *ptep, pte;
+
+ pgd = pgd_offset_k(address);
+ if (pgd_none(*pgd) || pgd_bad(*pgd))
+ return 0;
+
+ pud = pud_offset(pgd, address);
+ if (pud_none(*pud) || pud_bad(*pud))
+ return 0;
+
+ pmd = pmd_offset(pud, address);
+ if (pmd_none(*pmd) || pmd_bad(*pmd))
+ return 0;
+
+ ptep = pte_offset_kernel(pmd, address);
+ if (!ptep)
+ return 0;
+
+ pte = *ptep;
+ return pte_present(pte);
+}
+
+void
+ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)
+{
+ int signal = SIGSEGV, code = SEGV_MAPERR;
+ struct vm_area_struct *vma, *prev_vma;
+ struct mm_struct *mm = current->mm;
+ struct siginfo si;
+ unsigned long mask;
+
+ /*
+ * If we're in an interrupt or have no user context, we must not take the fault..
+ */
+ if (in_atomic() || !mm)
+ goto no_context;
+
+#ifdef CONFIG_VIRTUAL_MEM_MAP
+ /*
+ * If fault is in region 5 and we are in the kernel, we may already
+ * have the mmap_sem (pfn_valid macro is called during mmap). There
+ * is no vma for region 5 addr's anyway, so skip getting the semaphore
+ * and go directly to the exception handling code.
+ */
+
+ if ((REGION_NUMBER(address) == 5) && !user_mode(regs))
+ goto bad_area_no_up;
+#endif
+
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma_prev(mm, address, &prev_vma);
+ if (!vma)
+ goto bad_area;
+
+ /* find_vma_prev() returns vma such that address < vma->vm_end or NULL */
+ if (address < vma->vm_start)
+ goto check_expansion;
+
+ good_area:
+ code = SEGV_ACCERR;
+
+ /* OK, we've got a good vm_area for this memory area. Check the access permissions: */
+
+# define VM_READ_BIT 0
+# define VM_WRITE_BIT 1
+# define VM_EXEC_BIT 2
+
+# if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \
+ || (1 << VM_EXEC_BIT) != VM_EXEC)
+# error File is out of sync with <linux/mm.h>. Please update.
+# endif
+
+ mask = ( (((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
+ | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT)
+ | (((isr >> IA64_ISR_R_BIT) & 1UL) << VM_READ_BIT));
+
+ if ((vma->vm_flags & mask) != mask)
+ goto bad_area;
+
+ survive:
+ /*
+ * If for any reason at all we couldn't handle the fault, make
+ * sure we exit gracefully rather than endlessly redo the
+ * fault.
+ */
+ switch (handle_mm_fault(mm, vma, address, (mask & VM_WRITE) != 0)) {
+ case VM_FAULT_MINOR:
+ ++current->min_flt;
+ break;
+ case VM_FAULT_MAJOR:
+ ++current->maj_flt;
+ break;
+ case VM_FAULT_SIGBUS:
+ /*
+ * We ran out of memory, or some other thing happened
+ * to us that made us unable to handle the page fault
+ * gracefully.
+ */
+ signal = SIGBUS;
+ goto bad_area;
+ case VM_FAULT_OOM:
+ goto out_of_memory;
+ default:
+ BUG();
+ }
+ up_read(&mm->mmap_sem);
+ return;
+
+ check_expansion:
+ if (!(prev_vma && (prev_vma->vm_flags & VM_GROWSUP) && (address == prev_vma->vm_end))) {
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ goto bad_area;
+ if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
+ || REGION_OFFSET(address) >= RGN_MAP_LIMIT)
+ goto bad_area;
+ if (expand_stack(vma, address))
+ goto bad_area;
+ } else {
+ vma = prev_vma;
+ if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
+ || REGION_OFFSET(address) >= RGN_MAP_LIMIT)
+ goto bad_area;
+ if (expand_backing_store(vma, address))
+ goto bad_area;
+ }
+ goto good_area;
+
+ bad_area:
+ up_read(&mm->mmap_sem);
+#ifdef CONFIG_VIRTUAL_MEM_MAP
+ bad_area_no_up:
+#endif
+ if ((isr & IA64_ISR_SP)
+ || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
+ {
+ /*
+ * This fault was due to a speculative load or lfetch.fault, set the "ed"
+ * bit in the psr to ensure forward progress. (Target register will get a
+ * NaT for ld.s, lfetch will be canceled.)
+ */
+ ia64_psr(regs)->ed = 1;
+ return;
+ }
+ if (user_mode(regs)) {
+ si.si_signo = signal;
+ si.si_errno = 0;
+ si.si_code = code;
+ si.si_addr = (void __user *) address;
+ si.si_isr = isr;
+ si.si_flags = __ISR_VALID;
+ force_sig_info(signal, &si, current);
+ return;
+ }
+
+ no_context:
+ if (isr & IA64_ISR_SP) {
+ /*
+ * This fault was due to a speculative load set the "ed" bit in the psr to
+ * ensure forward progress (target register will get a NaT).
+ */
+ ia64_psr(regs)->ed = 1;
+ return;
+ }
+
+ if (ia64_done_with_exception(regs))
+ return;
+
+ /*
+ * Since we have no vma's for region 5, we might get here even if the address is
+ * valid, due to the VHPT walker inserting a non present translation that becomes
+ * stale. If that happens, the non present fault handler already purged the stale
+ * translation, which fixed the problem. So, we check to see if the translation is
+ * valid, and return if it is.
+ */
+ if (REGION_NUMBER(address) == 5 && mapped_kernel_page_is_present(address))
+ return;
+
+ /*
+ * Oops. The kernel tried to access some bad page. We'll have to terminate things
+ * with extreme prejudice.
+ */
+ bust_spinlocks(1);
+
+ if (address < PAGE_SIZE)
+ printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference (address %016lx)\n", address);
+ else
+ printk(KERN_ALERT "Unable to handle kernel paging request at "
+ "virtual address %016lx\n", address);
+ die("Oops", regs, isr);
+ bust_spinlocks(0);
+ do_exit(SIGKILL);
+ return;
+
+ out_of_memory:
+ up_read(&mm->mmap_sem);
+ if (current->pid == 1) {
+ yield();
+ down_read(&mm->mmap_sem);
+ goto survive;
+ }
+ printk(KERN_CRIT "VM: killing process %s\n", current->comm);
+ if (user_mode(regs))
+ do_exit(SIGKILL);
+ goto no_context;
+}