1 files changed, 405 insertions, 0 deletions

diff --git a/arch/mn10300/mm/fault.c b/arch/mn10300/mm/fault.c
new file mode 100644
index 000000000000..78f092ca0316
--- /dev/null
+++ b/arch/mn10300/mm/fault.c
@@ -0,0 +1,405 @@
+/* MN10300 MMU Fault handler
+ *
+ * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Modified by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/vt_kern.h>              /* For unblank_screen() */
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/pgalloc.h>
+#include <asm/hardirq.h>
+#include <asm/gdb-stub.h>
+#include <asm/cpu-regs.h>
+
+/*
+ * Unlock any spinlocks which will prevent us from getting the
+ * message out
+ */
+void bust_spinlocks(int yes)
+{
+        if (yes) {
+                oops_in_progress = 1;
+#ifdef CONFIG_SMP
+                /* Many serial drivers do __global_cli() */
+                global_irq_lock = 0;
+#endif
+        } else {
+                int loglevel_save = console_loglevel;
+#ifdef CONFIG_VT
+                unblank_screen();
+#endif
+                oops_in_progress = 0;
+                /*
+                 * OK, the message is on the console.  Now we call printk()
+                 * without oops_in_progress set so that printk will give klogd
+                 * a poke.  Hold onto your hats...
+                 */
+                console_loglevel = 15;  /* NMI oopser may have shut the console
+                                         * up */
+                printk(" ");
+                console_loglevel = loglevel_save;
+        }
+}
+
+void do_BUG(const char *file, int line)
+{
+        bust_spinlocks(1);
+        printk(KERN_EMERG "------------[ cut here ]------------\n");
+        printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
+}
+
+#if 0
+static void print_pagetable_entries(pgd_t *pgdir, unsigned long address)
+{
+        pgd_t *pgd;
+        pmd_t *pmd;
+        pte_t *pte;
+
+        pgd = pgdir + __pgd_offset(address);
+        printk(KERN_DEBUG "pgd entry %p: %016Lx\n",
+               pgd, (long long) pgd_val(*pgd));
+
+        if (!pgd_present(*pgd)) {
+                printk(KERN_DEBUG "... pgd not present!\n");
+                return;
+        }
+        pmd = pmd_offset(pgd, address);
+        printk(KERN_DEBUG "pmd entry %p: %016Lx\n",
+               pmd, (long long)pmd_val(*pmd));
+
+        if (!pmd_present(*pmd)) {
+                printk(KERN_DEBUG "... pmd not present!\n");
+                return;
+        }
+        pte = pte_offset(pmd, address);
+        printk(KERN_DEBUG "pte entry %p: %016Lx\n",
+               pte, (long long) pte_val(*pte));
+
+        if (!pte_present(*pte))
+                printk(KERN_DEBUG "... pte not present!\n");
+}
+#endif
+
+asmlinkage void monitor_signal(struct pt_regs *);
+
+/*
+ * This routine handles page faults.  It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ *
+ * fault_code:
+ * - LSW: either MMUFCR_IFC or MMUFCR_DFC as appropriate
+ * - MSW: 0 if data access, 1 if instruction access
+ * - bit 0: TLB miss flag
+ * - bit 1: initial write
+ * - bit 2: page invalid
+ * - bit 3: protection violation
+ * - bit 4: accessor (0=user 1=kernel)
+ * - bit 5: 0=read 1=write
+ * - bit 6-8: page protection spec
+ * - bit 9: illegal address
+ * - bit 16: 0=data 1=ins
+ *
+ */
+asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
+                              unsigned long address)
+{
+        struct vm_area_struct *vma;
+        struct task_struct *tsk;
+        struct mm_struct *mm;
+        unsigned long page;
+        siginfo_t info;
+        int write, fault;
+
+#ifdef CONFIG_GDBSTUB
+        /* handle GDB stub causing a fault */
+        if (gdbstub_busy) {
+                gdbstub_exception(regs, TBR & TBR_INT_CODE);
+                return;
+        }
+#endif
+
+#if 0
+        printk(KERN_DEBUG "--- do_page_fault(%p,%s:%04lx,%08lx)\n",
+               regs,
+               fault_code & 0x10000 ? "ins" : "data",
+               fault_code & 0xffff, address);
+#endif
+
+        tsk = current;
+
+        /*
+         * 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.
+         *
+         * This verifies that the fault happens in kernel space
+         * and that the fault was a page not present (invalid) error
+         */
+        if (address >= VMALLOC_START && address < VMALLOC_END &&
+            (fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR &&
+            (fault_code & MMUFCR_xFC_PGINVAL) == MMUFCR_xFC_PGINVAL
+            )
+                goto vmalloc_fault;
+
+        mm = tsk->mm;
+        info.si_code = SEGV_MAPERR;
+
+        /*
+         * If we're in an interrupt or have no user
+         * context, we must not take the fault..
+         */
+        if (in_interrupt() || !mm)
+                goto no_context;
+
+        down_read(&mm->mmap_sem);
+
+        vma = find_vma(mm, address);
+        if (!vma)
+                goto bad_area;
+        if (vma->vm_start <= address)
+                goto good_area;
+        if (!(vma->vm_flags & VM_GROWSDOWN))
+                goto bad_area;
+
+        if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
+                /* accessing the stack below the stack pointer is always a
+                 * bug */
+                if ((address & PAGE_MASK) + 2 * PAGE_SIZE < regs->sp) {
+#if 0
+                        printk(KERN_WARNING
+                               "[%d] ### Access below stack @%lx (sp=%lx)\n",
+                               current->pid, address, regs->sp);
+                        printk(KERN_WARNING
+                               "vma [%08x - %08x]\n",
+                               vma->vm_start, vma->vm_end);
+                        show_registers(regs);
+                        printk(KERN_WARNING
+                               "[%d] ### Code: [%08lx]"
+                               " %02x %02x %02x %02x %02x %02x %02x %02x\n",
+                               current->pid,
+                               regs->pc,
+                               ((u8 *) regs->pc)[0],
+                               ((u8 *) regs->pc)[1],
+                               ((u8 *) regs->pc)[2],
+                               ((u8 *) regs->pc)[3],
+                               ((u8 *) regs->pc)[4],
+                               ((u8 *) regs->pc)[5],
+                               ((u8 *) regs->pc)[6],
+                               ((u8 *) regs->pc)[7]
+                               );
+#endif
+                        goto bad_area;
+                }
+        }
+
+        if (expand_stack(vma, address))
+                goto bad_area;
+
+/*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it..
+ */
+good_area:
+        info.si_code = SEGV_ACCERR;
+        write = 0;
+        switch (fault_code & (MMUFCR_xFC_PGINVAL|MMUFCR_xFC_TYPE)) {
+        default:        /* 3: write, present */
+        case MMUFCR_xFC_TYPE_WRITE:
+#ifdef TEST_VERIFY_AREA
+                if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR)
+                        printk(KERN_DEBUG "WP fault at %08lx\n", regs->pc);
+#endif
+                /* write to absent page */
+        case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_WRITE:
+                if (!(vma->vm_flags & VM_WRITE))
+                        goto bad_area;
+                write++;
+                break;
+
+                /* read from protected page */
+        case MMUFCR_xFC_TYPE_READ:
+                goto bad_area;
+
+                /* read from absent page present */
+        case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_READ:
+                if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+                        goto bad_area;
+                break;
+        }
+
+        /*
+         * 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, write);
+        if (unlikely(fault & VM_FAULT_ERROR)) {
+                if (fault & VM_FAULT_OOM)
+                        goto out_of_memory;
+                else if (fault & VM_FAULT_SIGBUS)
+                        goto do_sigbus;
+                BUG();
+        }
+        if (fault & VM_FAULT_MAJOR)
+                current->maj_flt++;
+        else
+                current->min_flt++;
+
+        up_read(&mm->mmap_sem);
+        return;
+
+/*
+ * Something tried to access memory that isn't in our memory map..
+ * Fix it, but check if it's kernel or user first..
+ */
+bad_area:
+        up_read(&mm->mmap_sem);
+        monitor_signal(regs);
+
+        /* User mode accesses just cause a SIGSEGV */
+        if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
+                info.si_signo = SIGSEGV;
+                info.si_errno = 0;
+                /* info.si_code has been set above */
+                info.si_addr = (void *)address;
+                force_sig_info(SIGSEGV, &info, tsk);
+                return;
+        }
+
+no_context:
+        monitor_signal(regs);
+        /* Are we prepared to handle this kernel fault?  */
+        if (fixup_exception(regs))
+                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");
+        else
+                printk(KERN_ALERT
+                       "Unable to handle kernel paging request");
+        printk(" at virtual address %08lx\n", address);
+        printk(" printing pc:\n");
+        printk(KERN_ALERT "%08lx\n", regs->pc);
+
+#ifdef CONFIG_GDBSTUB
+        gdbstub_intercept(
+                regs, fault_code & 0x00010000 ? EXCEP_IAERROR : EXCEP_DAERROR);
+#endif
+
+        page = PTBR;
+        page = ((unsigned long *) __va(page))[address >> 22];
+        printk(KERN_ALERT "*pde = %08lx\n", page);
+        if (page & 1) {
+                page &= PAGE_MASK;
+                address &= 0x003ff000;
+                page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
+                printk(KERN_ALERT "*pte = %08lx\n", page);
+        }
+
+        die("Oops", regs, fault_code);
+        do_exit(SIGKILL);
+
+/*
+ * We ran out of memory, or some other thing happened to us that made
+ * us unable to handle the page fault gracefully.
+ */
+out_of_memory:
+        up_read(&mm->mmap_sem);
+        monitor_signal(regs);
+        printk(KERN_ALERT "VM: killing process %s\n", tsk->comm);
+        if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR)
+                do_exit(SIGKILL);
+        goto no_context;
+
+do_sigbus:
+        up_read(&mm->mmap_sem);
+        monitor_signal(regs);
+
+        /*
+         * Send a sigbus, regardless of whether we were in kernel
+         * or user mode.
+         */
+        info.si_signo = SIGBUS;
+        info.si_errno = 0;
+        info.si_code = BUS_ADRERR;
+        info.si_addr = (void *)address;
+        force_sig_info(SIGBUS, &info, tsk);
+
+        /* Kernel mode? Handle exceptions or die */
+        if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR)
+                goto no_context;
+        return;
+
+vmalloc_fault:
+        {
+                /*
+                 * Synchronize this task's top level page-table
+                 * with the 'reference' page table.
+                 *
+                 * Do _not_ use "tsk" here. We might be inside
+                 * an interrupt in the middle of a task switch..
+                 */
+                int index = pgd_index(address);
+                pgd_t *pgd, *pgd_k;
+                pud_t *pud, *pud_k;
+                pmd_t *pmd, *pmd_k;
+                pte_t *pte_k;
+
+                pgd_k = init_mm.pgd + index;
+
+                if (!pgd_present(*pgd_k))
+                        goto no_context;
+
+                pud_k = pud_offset(pgd_k, address);
+                if (!pud_present(*pud_k))
+                        goto no_context;
+
+                pmd_k = pmd_offset(pud_k, address);
+                if (!pmd_present(*pmd_k))
+                        goto no_context;
+
+                pgd = (pgd_t *) PTBR + index;
+                pud = pud_offset(pgd, address);
+                pmd = pmd_offset(pud, address);
+                set_pmd(pmd, *pmd_k);
+
+                pte_k = pte_offset_kernel(pmd_k, address);
+                if (!pte_present(*pte_k))
+                        goto no_context;
+                return;
+        }
+}