1 files changed, 325 insertions, 0 deletions

diff --git a/arch/frv/mm/fault.c b/arch/frv/mm/fault.c
new file mode 100644
index 000000000000..41d02ac48233
--- /dev/null
+++ b/arch/frv/mm/fault.c
@@ -0,0 +1,325 @@
+/*
+ *  linux/arch/frv/mm/fault.c
+ *
+ * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
+ * - Written by David Howells (dhowells@redhat.com)
+ * - Derived from arch/m68knommu/mm/fault.c
+ *   - Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
+ *   - Copyright (C) 2000  Lineo, Inc.  (www.lineo.com)
+ *
+ *  Based on:
+ *
+ *  linux/arch/m68k/mm/fault.c
+ *
+ *  Copyright (C) 1995  Hamish Macdonald
+ */
+
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/hardirq.h>
+
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/uaccess.h>
+#include <asm/gdb-stub.h>
+
+/*****************************************************************************/
+/*
+ * This routine handles page faults.  It determines the problem, and
+ * then passes it off to one of the appropriate routines.
+ */
+asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear0)
+{
+        struct vm_area_struct *vma;
+        struct mm_struct *mm;
+        unsigned long _pme, lrai, lrad, fixup;
+        siginfo_t info;
+        pgd_t *pge;
+        pud_t *pue;
+        pte_t *pte;
+        int write;
+
+#if 0
+        const char *atxc[16] = {
+                [0x0] = "mmu-miss", [0x8] = "multi-dat", [0x9] = "multi-sat",
+                [0xa] = "tlb-miss", [0xc] = "privilege", [0xd] = "write-prot",
+        };
+
+        printk("do_page_fault(%d,%lx [%s],%lx)\n",
+               datammu, esr0, atxc[esr0 >> 20 & 0xf], ear0);
+#endif
+
+        mm = current->mm;
+
+        /*
+         * 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 (!user_mode(__frame) && (esr0 & ESR0_ATXC) == ESR0_ATXC_AMRTLB_MISS) {
+                if (ear0 >= VMALLOC_START && ear0 < VMALLOC_END)
+                        goto kernel_pte_fault;
+                if (ear0 >= PKMAP_BASE && ear0 < PKMAP_END)
+                        goto kernel_pte_fault;
+        }
+
+        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, ear0);
+        if (!vma)
+                goto bad_area;
+        if (vma->vm_start <= ear0)
+                goto good_area;
+        if (!(vma->vm_flags & VM_GROWSDOWN))
+                goto bad_area;
+
+        if (user_mode(__frame)) {
+                /*
+                 * accessing the stack below %esp is always a bug.
+                 * The "+ 32" is there due to some instructions (like
+                 * pusha) doing post-decrement on the stack and that
+                 * doesn't show up until later..
+                 */
+                if ((ear0 & PAGE_MASK) + 2 * PAGE_SIZE < __frame->sp) {
+#if 0
+                        printk("[%d] ### Access below stack @%lx (sp=%lx)\n",
+                               current->pid, ear0, __frame->sp);
+                        show_registers(__frame);
+                        printk("[%d] ### Code: [%08lx] %02x %02x %02x %02x %02x %02x %02x %02x\n",
+                               current->pid,
+                               __frame->pc,
+                               ((u8*)__frame->pc)[0],
+                               ((u8*)__frame->pc)[1],
+                               ((u8*)__frame->pc)[2],
+                               ((u8*)__frame->pc)[3],
+                               ((u8*)__frame->pc)[4],
+                               ((u8*)__frame->pc)[5],
+                               ((u8*)__frame->pc)[6],
+                               ((u8*)__frame->pc)[7]
+                               );
+#endif
+                        goto bad_area;
+                }
+        }
+
+        if (expand_stack(vma, ear0))
+                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 (esr0 & ESR0_ATXC) {
+        default:
+                /* handle write to write protected page */
+        case ESR0_ATXC_WP_EXCEP:
+#ifdef TEST_VERIFY_AREA
+                if (!(user_mode(__frame)))
+                        printk("WP fault at %08lx\n", __frame->pc);
+#endif
+                if (!(vma->vm_flags & VM_WRITE))
+                        goto bad_area;
+                write = 1;
+                break;
+
+                 /* handle read from protected page */
+        case ESR0_ATXC_PRIV_EXCEP:
+                goto bad_area;
+
+                 /* handle read, write or exec on absent page
+                  * - can't support write without permitting read
+                  * - don't support execute without permitting read and vice-versa
+                  */
+        case ESR0_ATXC_AMRTLB_MISS:
+                if (!(vma->vm_flags & (VM_READ | VM_WRITE | 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.
+         */
+        switch (handle_mm_fault(mm, vma, ear0, write)) {
+        case 1:
+                current->min_flt++;
+                break;
+        case 2:
+                current->maj_flt++;
+                break;
+        case 0:
+                goto do_sigbus;
+        default:
+                goto out_of_memory;
+        }
+
+        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);
+
+        /* User mode accesses just cause a SIGSEGV */
+        if (user_mode(__frame)) {
+                info.si_signo = SIGSEGV;
+                info.si_errno = 0;
+                /* info.si_code has been set above */
+                info.si_addr = (void *) ear0;
+                force_sig_info(SIGSEGV, &info, current);
+                return;
+        }
+
+ no_context:
+        /* are we prepared to handle this kernel fault? */
+        if ((fixup = search_exception_table(__frame->pc)) != 0) {
+                __frame->pc = fixup;
+                return;
+        }
+
+/*
+ * Oops. The kernel tried to access some bad page. We'll have to
+ * terminate things with extreme prejudice.
+ */
+
+        bust_spinlocks(1);
+
+        if (ear0 < 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 addr %08lx\n", ear0);
+        printk("  PC  : %08lx\n", __frame->pc);
+        printk("  EXC : esr0=%08lx ear0=%08lx\n", esr0, ear0);
+
+        asm("lrai %1,%0,#1,#0,#0" : "=&r"(lrai) : "r"(ear0));
+        asm("lrad %1,%0,#1,#0,#0" : "=&r"(lrad) : "r"(ear0));
+
+        printk(KERN_ALERT "  LRAI: %08lx\n", lrai);
+        printk(KERN_ALERT "  LRAD: %08lx\n", lrad);
+
+        __break_hijack_kernel_event();
+
+        pge = pgd_offset(current->mm, ear0);
+        pue = pud_offset(pge, ear0);
+        _pme = pue->pue[0].ste[0];
+
+        printk(KERN_ALERT "  PGE : %8p { PME %08lx }\n", pge, _pme);
+
+        if (_pme & xAMPRx_V) {
+                unsigned long dampr, damlr, val;
+
+                asm volatile("movsg dampr2,%0 ! movgs %2,dampr2 ! movsg damlr2,%1"
+                             : "=&r"(dampr), "=r"(damlr)
+                             : "r" (_pme | xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V)
+                             );
+
+                pte = (pte_t *) damlr + __pte_index(ear0);
+                val = pte_val(*pte);
+
+                asm volatile("movgs %0,dampr2" :: "r" (dampr));
+
+                printk(KERN_ALERT "  PTE : %8p { %08lx }\n", pte, val);
+        }
+
+        die_if_kernel("Oops\n");
+        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);
+        printk("VM: killing process %s\n", current->comm);
+        if (user_mode(__frame))
+                do_exit(SIGKILL);
+        goto no_context;
+
+ do_sigbus:
+        up_read(&mm->mmap_sem);
+
+        /*
+         * 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 *) ear0;
+        force_sig_info(SIGBUS, &info, current);
+
+        /* Kernel mode? Handle exceptions or die */
+        if (!user_mode(__frame))
+                goto no_context;
+        return;
+
+/*
+ * The fault was caused by a kernel PTE (such as installed by vmalloc or kmap)
+ */
+ kernel_pte_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(ear0);
+                pgd_t *pgd, *pgd_k;
+                pud_t *pud, *pud_k;
+                pmd_t *pmd, *pmd_k;
+                pte_t *pte_k;
+
+                pgd = (pgd_t *) __get_TTBR();
+                pgd = (pgd_t *)__va(pgd) + index;
+                pgd_k = ((pgd_t *)(init_mm.pgd)) + index;
+
+                if (!pgd_present(*pgd_k))
+                        goto no_context;
+                //set_pgd(pgd, *pgd_k); /////// gcc ICE's on this line
+
+                pud_k = pud_offset(pgd_k, ear0);
+                if (!pud_present(*pud_k))
+                        goto no_context;
+
+                pmd_k = pmd_offset(pud_k, ear0);
+                if (!pmd_present(*pmd_k))
+                        goto no_context;
+
+                pud = pud_offset(pgd, ear0);
+                pmd = pmd_offset(pud, ear0);
+                set_pmd(pmd, *pmd_k);
+
+                pte_k = pte_offset_kernel(pmd_k, ear0);
+                if (!pte_present(*pte_k))
+                        goto no_context;
+                return;
+        }
+} /* end do_page_fault() */