--- /dev/null
+/*
+ * Copyright (C) 2004-2006 Atmel Corporation
+ *
+ * Based on linux/arch/sh/mm/fault.c:
+ * Copyright (C) 1999 Niibe Yutaka
+ *
+ * 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/mm.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+
+#include <asm/kdebug.h>
+#include <asm/mmu_context.h>
+#include <asm/sysreg.h>
+#include <asm/uaccess.h>
+#include <asm/tlb.h>
+
+#ifdef DEBUG
+static void dump_code(unsigned long pc)
+{
+ char *p = (char *)pc;
+ char val;
+ int i;
+
+
+ printk(KERN_DEBUG "Code:");
+ for (i = 0; i < 16; i++) {
+ if (__get_user(val, p + i))
+ break;
+ printk(" %02x", val);
+ }
+ printk("\n");
+}
+#endif
+
+#ifdef CONFIG_KPROBES
+ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
+
+/* Hook to register for page fault notifications */
+int register_page_fault_notifier(struct notifier_block *nb)
+{
+ return atomic_notifier_chain_register(¬ify_page_fault_chain, nb);
+}
+
+int unregister_page_fault_notifier(struct notifier_block *nb)
+{
+ return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb);
+}
+
+static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
+ int trap, int sig)
+{
+ struct die_args args = {
+ .regs = regs,
+ .trapnr = trap,
+ };
+ return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args);
+}
+#else
+static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
+ int trap, int sig)
+{
+ return NOTIFY_DONE;
+}
+#endif
+
+/*
+ * This routine handles page faults. It determines the address and the
+ * problem, and then passes it off to one of the appropriate routines.
+ *
+ * ecr is the Exception Cause Register. Possible values are:
+ * 5: Page not found (instruction access)
+ * 6: Protection fault (instruction access)
+ * 12: Page not found (read access)
+ * 13: Page not found (write access)
+ * 14: Protection fault (read access)
+ * 15: Protection fault (write access)
+ */
+asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
+{
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ const struct exception_table_entry *fixup;
+ unsigned long address;
+ unsigned long page;
+ int writeaccess = 0;
+
+ if (notify_page_fault(DIE_PAGE_FAULT, regs,
+ ecr, SIGSEGV) == NOTIFY_STOP)
+ return;
+
+ address = sysreg_read(TLBEAR);
+
+ 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 || regs->sr & SYSREG_BIT(GM))
+ goto no_context;
+
+ local_irq_enable();
+
+ 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 (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:
+ //pr_debug("good area: vm_flags = 0x%lx\n", vma->vm_flags);
+ switch (ecr) {
+ case ECR_PROTECTION_X:
+ case ECR_TLB_MISS_X:
+ if (!(vma->vm_flags & VM_EXEC))
+ goto bad_area;
+ break;
+ case ECR_PROTECTION_R:
+ case ECR_TLB_MISS_R:
+ if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
+ goto bad_area;
+ break;
+ case ECR_PROTECTION_W:
+ case ECR_TLB_MISS_W:
+ if (!(vma->vm_flags & VM_WRITE))
+ goto bad_area;
+ writeaccess = 1;
+ break;
+ default:
+ panic("Unhandled case %lu in do_page_fault!", ecr);
+ }
+
+ /*
+ * If for any reason at all we couldn't handle the fault, make
+ * sure we exit gracefully rather than endlessly redo the
+ * fault.
+ */
+survive:
+ switch (handle_mm_fault(mm, vma, address, writeaccess)) {
+ case VM_FAULT_MINOR:
+ tsk->min_flt++;
+ break;
+ case VM_FAULT_MAJOR:
+ tsk->maj_flt++;
+ break;
+ case VM_FAULT_SIGBUS:
+ goto do_sigbus;
+ case VM_FAULT_OOM:
+ goto out_of_memory;
+ default:
+ BUG();
+ }
+
+ 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:
+ pr_debug("Bad area [%s:%u]: addr %08lx, ecr %lu\n",
+ tsk->comm, tsk->pid, address, ecr);
+
+ up_read(&mm->mmap_sem);
+
+ if (user_mode(regs)) {
+ /* Hmm...we have to pass address and ecr somehow... */
+ /* tsk->thread.address = address;
+ tsk->thread.error_code = ecr; */
+#ifdef DEBUG
+ show_regs(regs);
+ dump_code(regs->pc);
+
+ page = sysreg_read(PTBR);
+ printk("ptbr = %08lx", page);
+ if (page) {
+ page = ((unsigned long *)page)[address >> 22];
+ printk(" pgd = %08lx", page);
+ if (page & _PAGE_PRESENT) {
+ page &= PAGE_MASK;
+ address &= 0x003ff000;
+ page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT];
+ printk(" pte = %08lx\n", page);
+ }
+ }
+#endif
+ pr_debug("Sending SIGSEGV to PID %d...\n",
+ tsk->pid);
+ force_sig(SIGSEGV, tsk);
+ return;
+ }
+
+no_context:
+ pr_debug("No context\n");
+
+ /* Are we prepared to handle this kernel fault? */
+ fixup = search_exception_tables(regs->pc);
+ if (fixup) {
+ regs->pc = fixup->fixup;
+ pr_debug("Found fixup at %08lx\n", fixup->fixup);
+ return;
+ }
+
+ /*
+ * Oops. The kernel tried to access some bad page. We'll have
+ * to terminate things with extreme prejudice.
+ */
+ 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(KERN_ALERT "pc = %08lx\n", regs->pc);
+
+ page = sysreg_read(PTBR);
+ printk(KERN_ALERT "ptbr = %08lx", page);
+ if (page) {
+ page = ((unsigned long *)page)[address >> 22];
+ printk(" pgd = %08lx", page);
+ if (page & _PAGE_PRESENT) {
+ page &= PAGE_MASK;
+ address &= 0x003ff000;
+ page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT];
+ printk(" pte = %08lx\n", page);
+ }
+ }
+ die("\nOops", regs, ecr);
+ 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:
+ printk("Out of memory\n");
+ up_read(&mm->mmap_sem);
+ if (current->pid == 1) {
+ yield();
+ down_read(&mm->mmap_sem);
+ goto survive;
+ }
+ printk("VM: Killing process %s\n", tsk->comm);
+ if (user_mode(regs))
+ 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.
+ */
+ /* address, error_code, trap_no, ... */
+#ifdef DEBUG
+ show_regs(regs);
+ dump_code(regs->pc);
+#endif
+ pr_debug("Sending SIGBUS to PID %d...\n", tsk->pid);
+ force_sig(SIGBUS, tsk);
+
+ /* Kernel mode? Handle exceptions or die */
+ if (!user_mode(regs))
+ goto no_context;
+}
+
+asmlinkage void do_bus_error(unsigned long addr, int write_access,
+ struct pt_regs *regs)
+{
+ printk(KERN_ALERT
+ "Bus error at physical address 0x%08lx (%s access)\n",
+ addr, write_access ? "write" : "read");
+ printk(KERN_INFO "DTLB dump:\n");
+ dump_dtlb();
+ die("Bus Error", regs, write_access);
+ do_exit(SIGKILL);
+}
+
+/*
+ * This functionality is currently not possible to implement because
+ * we're using segmentation to ensure a fixed mapping of the kernel
+ * virtual address space.
+ *
+ * It would be possible to implement this, but it would require us to
+ * disable segmentation at startup and load the kernel mappings into
+ * the TLB like any other pages. There will be lots of trickery to
+ * avoid recursive invocation of the TLB miss handler, though...
+ */
+#ifdef CONFIG_DEBUG_PAGEALLOC
+void kernel_map_pages(struct page *page, int numpages, int enable)
+{
+
+}
+EXPORT_SYMBOL(kernel_map_pages);
+#endif
git://git.onelab.eu / linux-2.6.git / blobdiff