1 files changed, 479 insertions, 0 deletions

diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c
new file mode 100644
index 00000000000..283aa4b50b7
--- /dev/null
+++ b/arch/unicore32/mm/fault.c
@@ -0,0 +1,479 @@
+/*
+ * linux/arch/unicore32/mm/fault.c
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/signal.h>
+#include <linux/mm.h>
+#include <linux/hardirq.h>
+#include <linux/init.h>
+#include <linux/kprobes.h>
+#include <linux/uaccess.h>
+#include <linux/page-flags.h>
+#include <linux/sched.h>
+#include <linux/io.h>
+
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+
+/*
+ * Fault status register encodings.  We steal bit 31 for our own purposes.
+ */
+#define FSR_LNX_PF              (1 << 31)
+
+static inline int fsr_fs(unsigned int fsr)
+{
+        /* xyabcde will be abcde+xy */
+        return (fsr & 31) + ((fsr & (3 << 5)) >> 5);
+}
+
+/*
+ * This is useful to dump out the page tables associated with
+ * 'addr' in mm 'mm'.
+ */
+void show_pte(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pgd;
+
+        if (!mm)
+                mm = &init_mm;
+
+        printk(KERN_ALERT "pgd = %p\n", mm->pgd);
+        pgd = pgd_offset(mm, addr);
+        printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));
+
+        do {
+                pmd_t *pmd;
+                pte_t *pte;
+
+                if (pgd_none(*pgd))
+                        break;
+
+                if (pgd_bad(*pgd)) {
+                        printk("(bad)");
+                        break;
+                }
+
+                pmd = pmd_offset((pud_t *) pgd, addr);
+                if (PTRS_PER_PMD != 1)
+                        printk(", *pmd=%08lx", 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_map(pmd, addr);
+                printk(", *pte=%08lx", pte_val(*pte));
+                pte_unmap(pte);
+        } while (0);
+
+        printk("\n");
+}
+
+/*
+ * Oops.  The kernel tried to access some page that wasn't present.
+ */
+static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
+                unsigned int fsr, struct pt_regs *regs)
+{
+        /*
+         * Are we prepared to handle this kernel fault?
+         */
+        if (fixup_exception(regs))
+                return;
+
+        /*
+         * No handler, we'll have to terminate things with extreme prejudice.
+         */
+        bust_spinlocks(1);
+        printk(KERN_ALERT
+               "Unable to handle kernel %s at virtual address %08lx\n",
+               (addr < PAGE_SIZE) ? "NULL pointer dereference" :
+               "paging request", addr);
+
+        show_pte(mm, addr);
+        die("Oops", regs, fsr);
+        bust_spinlocks(0);
+        do_exit(SIGKILL);
+}
+
+/*
+ * Something tried to access memory that isn't in our memory map..
+ * User mode accesses just cause a SIGSEGV
+ */
+static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
+                unsigned int fsr, unsigned int sig, int code,
+                struct pt_regs *regs)
+{
+        struct siginfo si;
+
+        tsk->thread.address = addr;
+        tsk->thread.error_code = fsr;
+        tsk->thread.trap_no = 14;
+        si.si_signo = sig;
+        si.si_errno = 0;
+        si.si_code = code;
+        si.si_addr = (void __user *)addr;
+        force_sig_info(sig, &si, tsk);
+}
+
+void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
+{
+        struct task_struct *tsk = current;
+        struct mm_struct *mm = tsk->active_mm;
+
+        /*
+         * If we are in kernel mode at this point, we
+         * have no context to handle this fault with.
+         */
+        if (user_mode(regs))
+                __do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
+        else
+                __do_kernel_fault(mm, addr, fsr, regs);
+}
+
+#define VM_FAULT_BADMAP         0x010000
+#define VM_FAULT_BADACCESS      0x020000
+
+/*
+ * Check that the permissions on the VMA allow for the fault which occurred.
+ * If we encountered a write fault, we must have write permission, otherwise
+ * we allow any permission.
+ */
+static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
+{
+        unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
+
+        if (!(fsr ^ 0x12))      /* write? */
+                mask = VM_WRITE;
+        if (fsr & FSR_LNX_PF)
+                mask = VM_EXEC;
+
+        return vma->vm_flags & mask ? false : true;
+}
+
+static int __do_pf(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
+                struct task_struct *tsk)
+{
+        struct vm_area_struct *vma;
+        int fault;
+
+        vma = find_vma(mm, addr);
+        fault = VM_FAULT_BADMAP;
+        if (unlikely(!vma))
+                goto out;
+        if (unlikely(vma->vm_start > addr))
+                goto check_stack;
+
+        /*
+         * Ok, we have a good vm_area for this
+         * memory access, so we can handle it.
+         */
+good_area:
+        if (access_error(fsr, vma)) {
+                fault = VM_FAULT_BADACCESS;
+                goto out;
+        }
+
+        /*
+         * 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, addr & PAGE_MASK,
+                            (!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0);
+        if (unlikely(fault & VM_FAULT_ERROR))
+                return fault;
+        if (fault & VM_FAULT_MAJOR)
+                tsk->maj_flt++;
+        else
+                tsk->min_flt++;
+        return fault;
+
+check_stack:
+        if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
+                goto good_area;
+out:
+        return fault;
+}
+
+static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
+{
+        struct task_struct *tsk;
+        struct mm_struct *mm;
+        int fault, sig, code;
+
+        tsk = current;
+        mm = tsk->mm;
+
+        /*
+         * If we're in an interrupt or have no user
+         * context, we must not take the fault..
+         */
+        if (in_atomic() || !mm)
+                goto no_context;
+
+        /*
+         * As per x86, we may deadlock here.  However, since the kernel only
+         * validly references user space from well defined areas of the code,
+         * we can bug out early if this is from code which shouldn't.
+         */
+        if (!down_read_trylock(&mm->mmap_sem)) {
+                if (!user_mode(regs)
+                    && !search_exception_tables(regs->UCreg_pc))
+                        goto no_context;
+                down_read(&mm->mmap_sem);
+        } else {
+                /*
+                 * The above down_read_trylock() might have succeeded in
+                 * which case, we'll have missed the might_sleep() from
+                 * down_read()
+                 */
+                might_sleep();
+#ifdef CONFIG_DEBUG_VM
+                if (!user_mode(regs) &&
+                    !search_exception_tables(regs->UCreg_pc))
+                        goto no_context;
+#endif
+        }
+
+        fault = __do_pf(mm, addr, fsr, tsk);
+        up_read(&mm->mmap_sem);
+
+        /*
+         * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
+         */
+        if (likely(!(fault &
+               (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
+                return 0;
+
+        if (fault & VM_FAULT_OOM) {
+                /*
+                 * We ran out of memory, call the OOM killer, and return to
+                 * userspace (which will retry the fault, or kill us if we
+                 * got oom-killed)
+                 */
+                pagefault_out_of_memory();
+                return 0;
+        }
+
+        /*
+         * If we are in kernel mode at this point, we
+         * have no context to handle this fault with.
+         */
+        if (!user_mode(regs))
+                goto no_context;
+
+        if (fault & VM_FAULT_SIGBUS) {
+                /*
+                 * We had some memory, but were unable to
+                 * successfully fix up this page fault.
+                 */
+                sig = SIGBUS;
+                code = BUS_ADRERR;
+        } else {
+                /*
+                 * Something tried to access memory that
+                 * isn't in our memory map..
+                 */
+                sig = SIGSEGV;
+                code = fault == VM_FAULT_BADACCESS ? SEGV_ACCERR : SEGV_MAPERR;
+        }
+
+        __do_user_fault(tsk, addr, fsr, sig, code, regs);
+        return 0;
+
+no_context:
+        __do_kernel_fault(mm, addr, fsr, regs);
+        return 0;
+}
+
+/*
+ * First Level Translation Fault Handler
+ *
+ * We enter here because the first level page table doesn't contain
+ * a valid entry for the address.
+ *
+ * If the address is in kernel space (>= TASK_SIZE), then we are
+ * probably faulting in the vmalloc() area.
+ *
+ * If the init_task's first level page tables contains the relevant
+ * entry, we copy the it to this task.  If not, we send the process
+ * a signal, fixup the exception, or oops the kernel.
+ *
+ * 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.
+ */
+static int do_ifault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
+{
+        unsigned int index;
+        pgd_t *pgd, *pgd_k;
+        pmd_t *pmd, *pmd_k;
+
+        if (addr < TASK_SIZE)
+                return do_pf(addr, fsr, regs);
+
+        if (user_mode(regs))
+                goto bad_area;
+
+        index = pgd_index(addr);
+
+        pgd = cpu_get_pgd() + index;
+        pgd_k = init_mm.pgd + index;
+
+        if (pgd_none(*pgd_k))
+                goto bad_area;
+
+        pmd_k = pmd_offset((pud_t *) pgd_k, addr);
+        pmd = pmd_offset((pud_t *) pgd, addr);
+
+        if (pmd_none(*pmd_k))
+                goto bad_area;
+
+        set_pmd(pmd, *pmd_k);
+        flush_pmd_entry(pmd);
+        return 0;
+
+bad_area:
+        do_bad_area(addr, fsr, regs);
+        return 0;
+}
+
+/*
+ * This abort handler always returns "fault".
+ */
+static int do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
+{
+        return 1;
+}
+
+static int do_good(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
+{
+        unsigned int res1, res2;
+
+        printk("dabt exception but no error!\n");
+
+        __asm__ __volatile__(
+                        "mff %0,f0\n"
+                        "mff %1,f1\n"
+                        : "=r"(res1), "=r"(res2)
+                        :
+                        : "memory");
+
+        printk(KERN_EMERG "r0 :%08x  r1 :%08x\n", res1, res2);
+        panic("shut up\n");
+        return 0;
+}
+
+static struct fsr_info {
+        int (*fn) (unsigned long addr, unsigned int fsr, struct pt_regs *regs);
+        int sig;
+        int code;
+        const char *name;
+} fsr_info[] = {
+        /*
+         * The following are the standard Unicore-I and UniCore-II aborts.
+         */
+        { do_good,      SIGBUS,  0,             "no error"              },
+        { do_bad,       SIGBUS,  BUS_ADRALN,    "alignment exception"   },
+        { do_bad,       SIGBUS,  BUS_OBJERR,    "external exception"    },
+        { do_bad,       SIGBUS,  0,             "burst operation"       },
+        { do_bad,       SIGBUS,  0,             "unknown 00100"         },
+        { do_ifault,    SIGSEGV, SEGV_MAPERR,   "2nd level pt non-exist"},
+        { do_bad,       SIGBUS,  0,             "2nd lvl large pt non-exist" },
+        { do_bad,       SIGBUS,  0,             "invalid pte"           },
+        { do_pf,        SIGSEGV, SEGV_MAPERR,   "page miss"             },
+        { do_bad,       SIGBUS,  0,             "middle page miss"      },
+        { do_bad,       SIGBUS,  0,             "large page miss"       },
+        { do_pf,        SIGSEGV, SEGV_MAPERR,   "super page (section) miss" },
+        { do_bad,       SIGBUS,  0,             "unknown 01100"         },
+        { do_bad,       SIGBUS,  0,             "unknown 01101"         },
+        { do_bad,       SIGBUS,  0,             "unknown 01110"         },
+        { do_bad,       SIGBUS,  0,             "unknown 01111"         },
+        { do_bad,       SIGBUS,  0,             "addr: up 3G or IO"     },
+        { do_pf,        SIGSEGV, SEGV_ACCERR,   "read unreadable addr"  },
+        { do_pf,        SIGSEGV, SEGV_ACCERR,   "write unwriteable addr"},
+        { do_pf,        SIGSEGV, SEGV_ACCERR,   "exec unexecutable addr"},
+        { do_bad,       SIGBUS,  0,             "unknown 10100"         },
+        { do_bad,       SIGBUS,  0,             "unknown 10101"         },
+        { do_bad,       SIGBUS,  0,             "unknown 10110"         },
+        { do_bad,       SIGBUS,  0,             "unknown 10111"         },
+        { do_bad,       SIGBUS,  0,             "unknown 11000"         },
+        { do_bad,       SIGBUS,  0,             "unknown 11001"         },
+        { do_bad,       SIGBUS,  0,             "unknown 11010"         },
+        { do_bad,       SIGBUS,  0,             "unknown 11011"         },
+        { do_bad,       SIGBUS,  0,             "unknown 11100"         },
+        { do_bad,       SIGBUS,  0,             "unknown 11101"         },
+        { do_bad,       SIGBUS,  0,             "unknown 11110"         },
+        { do_bad,       SIGBUS,  0,             "unknown 11111"         }
+};
+
+void __init hook_fault_code(int nr,
+                int (*fn) (unsigned long, unsigned int, struct pt_regs *),
+                int sig, int code, const char *name)
+{
+        if (nr < 0 || nr >= ARRAY_SIZE(fsr_info))
+                BUG();
+
+        fsr_info[nr].fn   = fn;
+        fsr_info[nr].sig  = sig;
+        fsr_info[nr].code = code;
+        fsr_info[nr].name = name;
+}
+
+/*
+ * Dispatch a data abort to the relevant handler.
+ */
+asmlinkage void do_DataAbort(unsigned long addr, unsigned int fsr,
+                        struct pt_regs *regs)
+{
+        const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
+        struct siginfo info;
+
+        if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
+                return;
+
+        printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
+               inf->name, fsr, addr);
+
+        info.si_signo = inf->sig;
+        info.si_errno = 0;
+        info.si_code = inf->code;
+        info.si_addr = (void __user *)addr;
+        uc32_notify_die("", regs, &info, fsr, 0);
+}
+
+asmlinkage void do_PrefetchAbort(unsigned long addr,
+                        unsigned int ifsr, struct pt_regs *regs)
+{
+        const struct fsr_info *inf = fsr_info + fsr_fs(ifsr);
+        struct siginfo info;
+
+        if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
+                return;
+
+        printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
+               inf->name, ifsr, addr);
+
+        info.si_signo = inf->sig;
+        info.si_errno = 0;
+        info.si_code = inf->code;
+        info.si_addr = (void __user *)addr;
+        uc32_notify_die("", regs, &info, ifsr, 0);
+}