1 files changed, 268 insertions, 0 deletions
diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
new file mode 100644
index 000000000..d223a8b57
--- /dev/null
+++ b/arch/avr32/mm/fault.c
@@ -0,0 +1,268 @@
+/*
+ * 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 <linux/kdebug.h>
+#include <linux/kprobes.h>
+
+#include <asm/mmu_context.h>
+#include <asm/sysreg.h>
+#include <asm/tlb.h>
+#include <asm/uaccess.h>
+
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+	int ret = 0;
+
+	if (!user_mode(regs)) {
+		if (kprobe_running() && kprobe_fault_handler(regs, trap))
+			ret = 1;
+	}
+
+	return ret;
+}
+#else
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+	return 0;
+}
+#endif
+
+int exception_trace = 1;
+
+/*
+ * 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:
+ *   6:  Protection fault (instruction access)
+ *   15: Protection fault (read access)
+ *   16: Protection fault (write access)
+ *   20: Page not found (instruction access)
+ *   24: Page not found (read access)
+ *   28: Page not found (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;
+	long signr;
+	int code;
+	int fault;
+	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+
+	if (notify_page_fault(regs, ecr))
+		return;
+
+	address = sysreg_read(TLBEAR);
+
+	tsk = current;
+	mm = tsk->mm;
+
+	signr = SIGSEGV;
+	code = SEGV_MAPERR;
+
+	/*
+	 * 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();
+
+	if (user_mode(regs))
+		flags |= FAULT_FLAG_USER;
+retry:
+	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:
+	code = SEGV_ACCERR;
+
+	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;
+		flags |= FAULT_FLAG_WRITE;
+		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.
+	 */
+	fault = handle_mm_fault(mm, vma, address, flags);
+
+	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+		return;
+
+	if (unlikely(fault & VM_FAULT_ERROR)) {
+		if (fault & VM_FAULT_OOM)
+			goto out_of_memory;
+		else if (fault & VM_FAULT_SIGSEGV)
+			goto bad_area;
+		else if (fault & VM_FAULT_SIGBUS)
+			goto do_sigbus;
+		BUG();
+	}
+
+	if (flags & FAULT_FLAG_ALLOW_RETRY) {
+		if (fault & VM_FAULT_MAJOR)
+			tsk->maj_flt++;
+		else
+			tsk->min_flt++;
+		if (fault & VM_FAULT_RETRY) {
+			flags &= ~FAULT_FLAG_ALLOW_RETRY;
+			flags |= FAULT_FLAG_TRIED;
+
+			/*
+			 * 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);
+	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);
+
+	if (user_mode(regs)) {
+		if (exception_trace && printk_ratelimit())
+			printk("%s%s[%d]: segfault at %08lx pc %08lx "
+			       "sp %08lx ecr %lu\n",
+			       is_global_init(tsk) ? KERN_EMERG : KERN_INFO,
+			       tsk->comm, tsk->pid, address, regs->pc,
+			       regs->sp, ecr);
+		_exception(SIGSEGV, regs, code, address);
+		return;
+	}
+
+no_context:
+	/* Are we prepared to handle this kernel fault? */
+	fixup = search_exception_tables(regs->pc);
+	if (fixup) {
+		regs->pc = 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);
+
+	page = sysreg_read(PTBR);
+	printk(KERN_ALERT "ptbr = %08lx", page);
+	if (address >= TASK_SIZE)
+		page = (unsigned long)swapper_pg_dir;
+	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", page);
+		}
+	}
+	printk("\n");
+	die("Kernel access of bad area", regs, signr);
+	return;
+
+	/*
+	 * 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);
+	if (!user_mode(regs))
+		goto no_context;
+	pagefault_out_of_memory();
+	return;
+
+do_sigbus:
+	up_read(&mm->mmap_sem);
+
+	/* Kernel mode? Handle exceptions or die */
+	signr = SIGBUS;
+	code = BUS_ADRERR;
+	if (!user_mode(regs))
+		goto no_context;
+
+	if (exception_trace)
+		printk("%s%s[%d]: bus error at %08lx pc %08lx "
+		       "sp %08lx ecr %lu\n",
+		       is_global_init(tsk) ? KERN_EMERG : KERN_INFO,
+		       tsk->comm, tsk->pid, address, regs->pc,
+		       regs->sp, ecr);
+
+	_exception(SIGBUS, regs, BUS_ADRERR, address);
+}
+
+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, SIGKILL);
+}