1 files changed, 508 insertions, 0 deletions

diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
new file mode 100644
index 00000000000..16799f920f9
--- /dev/null
+++ b/arch/sh/mm/fault.c
@@ -0,0 +1,508 @@
+/*
+ * Page fault handler for SH with an MMU.
+ *
+ *  Copyright (C) 1999  Niibe Yutaka
+ *  Copyright (C) 2003 - 2012  Paul Mundt
+ *
+ *  Based on linux/arch/i386/mm/fault.c:
+ *   Copyright (C) 1995  Linus Torvalds
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/hardirq.h>
+#include <linux/kprobes.h>
+#include <linux/perf_event.h>
+#include <linux/kdebug.h>
+#include <asm/io_trapped.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/traps.h>
+
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+        int ret = 0;
+
+        if (kprobes_built_in() && !user_mode(regs)) {
+                preempt_disable();
+                if (kprobe_running() && kprobe_fault_handler(regs, trap))
+                        ret = 1;
+                preempt_enable();
+        }
+
+        return ret;
+}
+
+static void
+force_sig_info_fault(int si_signo, int si_code, unsigned long address,
+                     struct task_struct *tsk)
+{
+        siginfo_t info;
+
+        info.si_signo   = si_signo;
+        info.si_errno   = 0;
+        info.si_code    = si_code;
+        info.si_addr    = (void __user *)address;
+
+        force_sig_info(si_signo, &info, tsk);
+}
+
+/*
+ * This is useful to dump out the page tables associated with
+ * 'addr' in mm 'mm'.
+ */
+static void show_pte(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pgd;
+
+        if (mm)
+                pgd = mm->pgd;
+        else
+                pgd = get_TTB();
+
+        printk(KERN_ALERT "pgd = %p\n", pgd);
+        pgd += pgd_index(addr);
+        printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr,
+               (u32)(sizeof(*pgd) * 2), (u64)pgd_val(*pgd));
+
+        do {
+                pud_t *pud;
+                pmd_t *pmd;
+                pte_t *pte;
+
+                if (pgd_none(*pgd))
+                        break;
+
+                if (pgd_bad(*pgd)) {
+                        printk("(bad)");
+                        break;
+                }
+
+                pud = pud_offset(pgd, addr);
+                if (PTRS_PER_PUD != 1)
+                        printk(", *pud=%0*Lx", (u32)(sizeof(*pud) * 2),
+                               (u64)pud_val(*pud));
+
+                if (pud_none(*pud))
+                        break;
+
+                if (pud_bad(*pud)) {
+                        printk("(bad)");
+                        break;
+                }
+
+                pmd = pmd_offset(pud, addr);
+                if (PTRS_PER_PMD != 1)
+                        printk(", *pmd=%0*Lx", (u32)(sizeof(*pmd) * 2),
+                               (u64)pmd_val(*pmd));
+
+                if (pmd_none(*pmd))
+                        break;
+
+                if (pmd_bad(*pmd)) {
+                        printk("(bad)");
+                        break;
+                }
+
+                /* We must not map this if we have highmem enabled */
+                if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
+                        break;
+
+                pte = pte_offset_kernel(pmd, addr);
+                printk(", *pte=%0*Lx", (u32)(sizeof(*pte) * 2),
+                       (u64)pte_val(*pte));
+        } while (0);
+
+        printk("\n");
+}
+
+static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
+{
+        unsigned index = pgd_index(address);
+        pgd_t *pgd_k;
+        pud_t *pud, *pud_k;
+        pmd_t *pmd, *pmd_k;
+
+        pgd += index;
+        pgd_k = init_mm.pgd + index;
+
+        if (!pgd_present(*pgd_k))
+                return NULL;
+
+        pud = pud_offset(pgd, address);
+        pud_k = pud_offset(pgd_k, address);
+        if (!pud_present(*pud_k))
+                return NULL;
+
+        if (!pud_present(*pud))
+            set_pud(pud, *pud_k);
+
+        pmd = pmd_offset(pud, address);
+        pmd_k = pmd_offset(pud_k, address);
+        if (!pmd_present(*pmd_k))
+                return NULL;
+
+        if (!pmd_present(*pmd))
+                set_pmd(pmd, *pmd_k);
+        else {
+                /*
+                 * The page tables are fully synchronised so there must
+                 * be another reason for the fault. Return NULL here to
+                 * signal that we have not taken care of the fault.
+                 */
+                BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
+                return NULL;
+        }
+
+        return pmd_k;
+}
+
+/*
+ * Handle a fault on the vmalloc or module mapping area
+ */
+static noinline int vmalloc_fault(unsigned long address)
+{
+        pgd_t *pgd_k;
+        pmd_t *pmd_k;
+        pte_t *pte_k;
+
+        /* Make sure we are in vmalloc/module area: */
+        if (!is_vmalloc_addr((void *)address))
+                return -1;
+
+        /*
+         * Synchronize this task's top level page-table
+         * with the 'reference' page table.
+         *
+         * Do _not_ use "current" here. We might be inside
+         * an interrupt in the middle of a task switch..
+         */
+        pgd_k = get_TTB();
+        pmd_k = vmalloc_sync_one(pgd_k, address);
+        if (!pmd_k)
+                return -1;
+
+        pte_k = pte_offset_kernel(pmd_k, address);
+        if (!pte_present(*pte_k))
+                return -1;
+
+        return 0;
+}
+
+static void
+show_fault_oops(struct pt_regs *regs, unsigned long address)
+{
+        if (!oops_may_print())
+                return;
+
+        printk(KERN_ALERT "BUG: unable to handle kernel ");
+        if (address < PAGE_SIZE)
+                printk(KERN_CONT "NULL pointer dereference");
+        else
+                printk(KERN_CONT "paging request");
+
+        printk(KERN_CONT " at %08lx\n", address);
+        printk(KERN_ALERT "PC:");
+        printk_address(regs->pc, 1);
+
+        show_pte(NULL, address);
+}
+
+static noinline void
+no_context(struct pt_regs *regs, unsigned long error_code,
+           unsigned long address)
+{
+        /* Are we prepared to handle this kernel fault?  */
+        if (fixup_exception(regs))
+                return;
+
+        if (handle_trapped_io(regs, address))
+                return;
+
+        /*
+         * Oops. The kernel tried to access some bad page. We'll have to
+         * terminate things with extreme prejudice.
+         */
+        bust_spinlocks(1);
+
+        show_fault_oops(regs, address);
+
+        die("Oops", regs, error_code);
+        bust_spinlocks(0);
+        do_exit(SIGKILL);
+}
+
+static void
+__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
+                       unsigned long address, int si_code)
+{
+        struct task_struct *tsk = current;
+
+        /* User mode accesses just cause a SIGSEGV */
+        if (user_mode(regs)) {
+                /*
+                 * It's possible to have interrupts off here:
+                 */
+                local_irq_enable();
+
+                force_sig_info_fault(SIGSEGV, si_code, address, tsk);
+
+                return;
+        }
+
+        no_context(regs, error_code, address);
+}
+
+static noinline void
+bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
+                     unsigned long address)
+{
+        __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
+}
+
+static void
+__bad_area(struct pt_regs *regs, unsigned long error_code,
+           unsigned long address, int si_code)
+{
+        struct mm_struct *mm = current->mm;
+
+        /*
+         * Something tried to access memory that isn't in our memory map..
+         * Fix it, but check if it's kernel or user first..
+         */
+        up_read(&mm->mmap_sem);
+
+        __bad_area_nosemaphore(regs, error_code, address, si_code);
+}
+
+static noinline void
+bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+{
+        __bad_area(regs, error_code, address, SEGV_MAPERR);
+}
+
+static noinline void
+bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
+                      unsigned long address)
+{
+        __bad_area(regs, error_code, address, SEGV_ACCERR);
+}
+
+static void out_of_memory(void)
+{
+        /*
+         * We ran out of memory, call the OOM killer, and return the userspace
+         * (which will retry the fault, or kill us if we got oom-killed):
+         */
+        up_read(&current->mm->mmap_sem);
+
+        pagefault_out_of_memory();
+}
+
+static void
+do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+{
+        struct task_struct *tsk = current;
+        struct mm_struct *mm = tsk->mm;
+
+        up_read(&mm->mmap_sem);
+
+        /* Kernel mode? Handle exceptions or die: */
+        if (!user_mode(regs))
+                no_context(regs, error_code, address);
+
+        force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
+}
+
+static noinline int
+mm_fault_error(struct pt_regs *regs, unsigned long error_code,
+               unsigned long address, unsigned int fault)
+{
+        /*
+         * Pagefault was interrupted by SIGKILL. We have no reason to
+         * continue pagefault.
+         */
+        if (fatal_signal_pending(current)) {
+                if (!(fault & VM_FAULT_RETRY))
+                        up_read(&current->mm->mmap_sem);
+                if (!user_mode(regs))
+                        no_context(regs, error_code, address);
+                return 1;
+        }
+
+        if (!(fault & VM_FAULT_ERROR))
+                return 0;
+
+        if (fault & VM_FAULT_OOM) {
+                /* Kernel mode? Handle exceptions or die: */
+                if (!user_mode(regs)) {
+                        up_read(&current->mm->mmap_sem);
+                        no_context(regs, error_code, address);
+                        return 1;
+                }
+
+                out_of_memory();
+        } else {
+                if (fault & VM_FAULT_SIGBUS)
+                        do_sigbus(regs, error_code, address);
+                else
+                        BUG();
+        }
+
+        return 1;
+}
+
+static inline int access_error(int error_code, struct vm_area_struct *vma)
+{
+        if (error_code & FAULT_CODE_WRITE) {
+                /* write, present and write, not present: */
+                if (unlikely(!(vma->vm_flags & VM_WRITE)))
+                        return 1;
+                return 0;
+        }
+
+        /* ITLB miss on NX page */
+        if (unlikely((error_code & FAULT_CODE_ITLB) &&
+                     !(vma->vm_flags & VM_EXEC)))
+                return 1;
+
+        /* read, not present: */
+        if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
+                return 1;
+
+        return 0;
+}
+
+static int fault_in_kernel_space(unsigned long address)
+{
+        return address >= TASK_SIZE;
+}
+
+/*
+ * This routine handles page faults.  It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ */
+asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
+                                        unsigned long error_code,
+                                        unsigned long address)
+{
+        unsigned long vec;
+        struct task_struct *tsk;
+        struct mm_struct *mm;
+        struct vm_area_struct * vma;
+        int fault;
+        int write = error_code & FAULT_CODE_WRITE;
+        unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
+                              (write ? FAULT_FLAG_WRITE : 0));
+
+        tsk = current;
+        mm = tsk->mm;
+        vec = lookup_exception_vector();
+
+        /*
+         * We fault-in kernel-space virtual memory on-demand. The
+         * 'reference' page table is init_mm.pgd.
+         *
+         * NOTE! We MUST NOT take any locks for this case. We may
+         * be in an interrupt or a critical region, and should
+         * only copy the information from the master page table,
+         * nothing more.
+         */
+        if (unlikely(fault_in_kernel_space(address))) {
+                if (vmalloc_fault(address) >= 0)
+                        return;
+                if (notify_page_fault(regs, vec))
+                        return;
+
+                bad_area_nosemaphore(regs, error_code, address);
+                return;
+        }
+
+        if (unlikely(notify_page_fault(regs, vec)))
+                return;
+
+        /* Only enable interrupts if they were on before the fault */
+        if ((regs->sr & SR_IMASK) != SR_IMASK)
+                local_irq_enable();
+
+        perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+
+        /*
+         * If we're in an interrupt, have no user context or are running
+         * in an atomic region then we must not take the fault:
+         */
+        if (unlikely(in_atomic() || !mm)) {
+                bad_area_nosemaphore(regs, error_code, address);
+                return;
+        }
+
+retry:
+        down_read(&mm->mmap_sem);
+
+        vma = find_vma(mm, address);
+        if (unlikely(!vma)) {
+                bad_area(regs, error_code, address);
+                return;
+        }
+        if (likely(vma->vm_start <= address))
+                goto good_area;
+        if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
+                bad_area(regs, error_code, address);
+                return;
+        }
+        if (unlikely(expand_stack(vma, address))) {
+                bad_area(regs, error_code, address);
+                return;
+        }
+
+        /*
+         * Ok, we have a good vm_area for this memory access, so
+         * we can handle it..
+         */
+good_area:
+        if (unlikely(access_error(error_code, vma))) {
+                bad_area_access_error(regs, error_code, address);
+                return;
+        }
+
+        set_thread_fault_code(error_code);
+
+        /*
+         * If for any reason at all we couldn't handle the fault,
+         * make sure we exit gracefully rather than endlessly redo
+         * the fault.
+         */
+        fault = handle_mm_fault(mm, vma, address, flags);
+
+        if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
+                if (mm_fault_error(regs, error_code, address, fault))
+                        return;
+
+        if (flags & FAULT_FLAG_ALLOW_RETRY) {
+                if (fault & VM_FAULT_MAJOR) {
+                        tsk->maj_flt++;
+                        perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
+                                      regs, address);
+                } else {
+                        tsk->min_flt++;
+                        perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
+                                      regs, address);
+                }
+                if (fault & VM_FAULT_RETRY) {
+                        flags &= ~FAULT_FLAG_ALLOW_RETRY;
+
+                        /*
+                         * No need to up_read(&mm->mmap_sem) as we would
+                         * have already released it in __lock_page_or_retry
+                         * in mm/filemap.c.
+                         */
+                        goto retry;
+                }
+        }
+
+        up_read(&mm->mmap_sem);
+}