[AVR32] Clean up exception handling code

  * Use generic BUG() handling
  * Remove some useless debug statements
  * Use a common function _exception() to send signals or oops when
    an exception can't be handled. This makes sure init doesn't
    enter an infinite exception loop as well. Borrowed from powerpc.
  * Add some basic exception tracing support to the page fault code.
  * Rework dump_stack(), show_regs() and friends and move everything
    into process.c
  * Print information about configuration options and chip type when
    oopsing

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

6 files changed, 357 insertions, 393 deletions

diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index 257b83648cb7..7a1eb445c17f 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -68,6 +68,11 @@ config GENERIC_CALIBRATE_DELAY
         bool
         default y
 
+config GENERIC_BUG
+        bool
+        default y
+        depends on BUG
+
 source "init/Kconfig"
 
 menu "System Type and features"
diff --git a/arch/avr32/kernel/module.c b/arch/avr32/kernel/module.c
index b599eae64576..1167fe9cf6c4 100644
--- a/arch/avr32/kernel/module.c
+++ b/arch/avr32/kernel/module.c
@@ -12,10 +12,11 @@
  * published by the Free Software Foundation.
  */
 
-#include <linux/moduleloader.h>
-#include <linux/module.h>
-#include <linux/kernel.h>
+#include <linux/bug.h>
 #include <linux/elf.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleloader.h>
 #include <linux/vmalloc.h>
 
 void *module_alloc(unsigned long size)
@@ -315,10 +316,10 @@ int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
         vfree(module->arch.syminfo);
         module->arch.syminfo = NULL;
 
-        return 0;
+        return module_bug_finalize(hdr, sechdrs, module);
 }
 
 void module_arch_cleanup(struct module *module)
 {
-
+        module_bug_cleanup(module);
 }
diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c
index 4f8d2d474740..4e4181ed1c6d 100644
--- a/arch/avr32/kernel/process.c
+++ b/arch/avr32/kernel/process.c
@@ -11,6 +11,7 @@
 #include <linux/fs.h>
 #include <linux/ptrace.h>
 #include <linux/reboot.h>
+#include <linux/uaccess.h>
 #include <linux/unistd.h>
 
 #include <asm/sysreg.h>
@@ -115,39 +116,178 @@ void release_thread(struct task_struct *dead_task)
         /* do nothing */
 }
 
+static void dump_mem(const char *str, const char *log_lvl,
+                     unsigned long bottom, unsigned long top)
+{
+        unsigned long p;
+        int i;
+
+        printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);
+
+        for (p = bottom & ~31; p < top; ) {
+                printk("%s%04lx: ", log_lvl, p & 0xffff);
+
+                for (i = 0; i < 8; i++, p += 4) {
+                        unsigned int val;
+
+                        if (p < bottom || p >= top)
+                                printk("         ");
+                        else {
+                                if (__get_user(val, (unsigned int __user *)p)) {
+                                        printk("\n");
+                                        goto out;
+                                }
+                                printk("%08x ", val);
+                        }
+                }
+                printk("\n");
+        }
+
+out:
+        return;
+}
+
+static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
+{
+        return (p > (unsigned long)tinfo)
+                && (p < (unsigned long)tinfo + THREAD_SIZE - 3);
+}
+
+#ifdef CONFIG_FRAME_POINTER
+static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
+                               struct pt_regs *regs, const char *log_lvl)
+{
+        unsigned long lr, fp;
+        struct thread_info *tinfo;
+
+        if (regs)
+                fp = regs->r7;
+        else if (tsk == current)
+                asm("mov %0, r7" : "=r"(fp));
+        else
+                fp = tsk->thread.cpu_context.r7;
+
+        /*
+         * Walk the stack as long as the frame pointer (a) is within
+         * the kernel stack of the task, and (b) it doesn't move
+         * downwards.
+         */
+        tinfo = task_thread_info(tsk);
+        printk("%sCall trace:\n", log_lvl);
+        while (valid_stack_ptr(tinfo, fp)) {
+                unsigned long new_fp;
+
+                lr = *(unsigned long *)fp;
+#ifdef CONFIG_KALLSYMS
+                printk("%s [<%08lx>] ", log_lvl, lr);
+#else
+                printk(" [<%08lx>] ", lr);
+#endif
+                print_symbol("%s\n", lr);
+
+                new_fp = *(unsigned long *)(fp + 4);
+                if (new_fp <= fp)
+                        break;
+                fp = new_fp;
+        }
+        printk("\n");
+}
+#else
+static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
+                               struct pt_regs *regs, const char *log_lvl)
+{
+        unsigned long addr;
+
+        printk("%sCall trace:\n", log_lvl);
+
+        while (!kstack_end(sp)) {
+                addr = *sp++;
+                if (kernel_text_address(addr)) {
+#ifdef CONFIG_KALLSYMS
+                        printk("%s [<%08lx>] ", log_lvl, addr);
+#else
+                        printk(" [<%08lx>] ", addr);
+#endif
+                        print_symbol("%s\n", addr);
+                }
+        }
+        printk("\n");
+}
+#endif
+
+void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
+                        struct pt_regs *regs, const char *log_lvl)
+{
+        struct thread_info *tinfo;
+
+        if (sp == 0) {
+                if (tsk)
+                        sp = tsk->thread.cpu_context.ksp;
+                else
+                        sp = (unsigned long)&tinfo;
+        }
+        if (!tsk)
+                tsk = current;
+
+        tinfo = task_thread_info(tsk);
+
+        if (valid_stack_ptr(tinfo, sp)) {
+                dump_mem("Stack: ", log_lvl, sp,
+                         THREAD_SIZE + (unsigned long)tinfo);
+                show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
+        }
+}
+
+void show_stack(struct task_struct *tsk, unsigned long *stack)
+{
+        show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
+}
+
+void dump_stack(void)
+{
+        unsigned long stack;
+
+        show_trace_log_lvl(current, &stack, NULL, "");
+}
+EXPORT_SYMBOL(dump_stack);
+
 static const char *cpu_modes[] = {
         "Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
         "Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
 };
 
-void show_regs(struct pt_regs *regs)
+void show_regs_log_lvl(struct pt_regs *regs, const char *log_lvl)
 {
         unsigned long sp = regs->sp;
         unsigned long lr = regs->lr;
         unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;
 
-        if (!user_mode(regs))
+        if (!user_mode(regs)) {
                 sp = (unsigned long)regs + FRAME_SIZE_FULL;
 
-        print_symbol("PC is at %s\n", instruction_pointer(regs));
-        print_symbol("LR is at %s\n", lr);
-        printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
-               "sp : %08lx  r12: %08lx  r11: %08lx\n",
-               instruction_pointer(regs),
-               lr, print_tainted(), sp, regs->r12, regs->r11);
-        printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
-               regs->r10, regs->r9, regs->r8);
-        printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
-               regs->r7, regs->r6, regs->r5, regs->r4);
-        printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
-               regs->r3, regs->r2, regs->r1, regs->r0);
-        printk("Flags: %c%c%c%c%c\n",
+                printk("%s", log_lvl);
+                print_symbol("PC is at %s\n", instruction_pointer(regs));
+                printk("%s", log_lvl);
+                print_symbol("LR is at %s\n", lr);
+        }
+
+        printk("%spc : [<%08lx>]    lr : [<%08lx>]    %s\n"
+               "%ssp : %08lx  r12: %08lx  r11: %08lx\n",
+               log_lvl, instruction_pointer(regs), lr, print_tainted(),
+               log_lvl, sp, regs->r12, regs->r11);
+        printk("%sr10: %08lx  r9 : %08lx  r8 : %08lx\n",
+               log_lvl, regs->r10, regs->r9, regs->r8);
+        printk("%sr7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
+               log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
+        printk("%sr3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
+               log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
+        printk("%sFlags: %c%c%c%c%c\n", log_lvl,
                regs->sr & SR_Q ? 'Q' : 'q',
                regs->sr & SR_V ? 'V' : 'v',
                regs->sr & SR_N ? 'N' : 'n',
                regs->sr & SR_Z ? 'Z' : 'z',
                regs->sr & SR_C ? 'C' : 'c');
-        printk("Mode bits: %c%c%c%c%c%c%c%c%c\n",
+        printk("%sMode bits: %c%c%c%c%c%c%c%c%c\n", log_lvl,
                regs->sr & SR_H ? 'H' : 'h',
                regs->sr & SR_R ? 'R' : 'r',
                regs->sr & SR_J ? 'J' : 'j',
@@ -157,9 +297,21 @@ void show_regs(struct pt_regs *regs)
                regs->sr & SR_I1M ? '1' : '.',
                regs->sr & SR_I0M ? '0' : '.',
                regs->sr & SR_GM ? 'G' : 'g');
-        printk("CPU Mode: %s\n", cpu_modes[mode]);
+        printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
+        printk("%sProcess: %s [%d] (task: %p thread: %p)\n",
+               log_lvl, current->comm, current->pid, current,
+               task_thread_info(current));
+}
+
+void show_regs(struct pt_regs *regs)
+{
+        unsigned long sp = regs->sp;
+
+        if (!user_mode(regs))
+                sp = (unsigned long)regs + FRAME_SIZE_FULL;
 
-        show_trace(NULL, (unsigned long *)sp, regs);
+        show_regs_log_lvl(regs, "");
+        show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
 }
 EXPORT_SYMBOL(show_regs);
 
diff --git a/arch/avr32/kernel/traps.c b/arch/avr32/kernel/traps.c
index adc01a12d154..4f0382d8483f 100644
--- a/arch/avr32/kernel/traps.c
+++ b/arch/avr32/kernel/traps.c
@@ -5,158 +5,25 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
-#undef DEBUG
-#include <linux/sched.h>
+
+#include <linux/bug.h>
 #include <linux/init.h>
-#include <linux/module.h>
 #include <linux/kallsyms.h>
+#include <linux/module.h>
 #include <linux/notifier.h>
+#include <linux/sched.h>
+#include <linux/uaccess.h>
 
-#include <asm/traps.h>
-#include <asm/sysreg.h>
 #include <asm/addrspace.h>
-#include <asm/ocd.h>
 #include <asm/mmu_context.h>
-#include <asm/uaccess.h>
-
-static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
-{
-        unsigned long p;
-        int i;
-
-        printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
-
-        for (p = bottom & ~31; p < top; ) {
-                printk("%04lx: ", p & 0xffff);
-
-                for (i = 0; i < 8; i++, p += 4) {
-                        unsigned int val;
-
-                        if (p < bottom || p >= top)
-                                printk("         ");
-                        else {
-                                if (__get_user(val, (unsigned int __user *)p)) {
-                                        printk("\n");
-                                        goto out;
-                                }
-                                printk("%08x ", val);
-                        }
-                }
-                printk("\n");
-        }
-
-out:
-        return;
-}
-
-static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
-{
-        return (p > (unsigned long)tinfo)
-                && (p < (unsigned long)tinfo + THREAD_SIZE - 3);
-}
-
-#ifdef CONFIG_FRAME_POINTER
-static inline void __show_trace(struct task_struct *tsk, unsigned long *sp,
-                                struct pt_regs *regs)
-{
-        unsigned long lr, fp;
-        struct thread_info *tinfo;
-
-        tinfo = (struct thread_info *)
-                ((unsigned long)sp & ~(THREAD_SIZE - 1));
-
-        if (regs)
-                fp = regs->r7;
-        else if (tsk == current)
-                asm("mov %0, r7" : "=r"(fp));
-        else
-                fp = tsk->thread.cpu_context.r7;
-
-        /*
-         * Walk the stack as long as the frame pointer (a) is within
-         * the kernel stack of the task, and (b) it doesn't move
-         * downwards.
-         */
-        while (valid_stack_ptr(tinfo, fp)) {
-                unsigned long new_fp;
-
-                lr = *(unsigned long *)fp;
-                printk(" [<%08lx>] ", lr);
-                print_symbol("%s\n", lr);
-
-                new_fp = *(unsigned long *)(fp + 4);
-                if (new_fp <= fp)
-                        break;
-                fp = new_fp;
-        }
-        printk("\n");
-}
-#else
-static inline void __show_trace(struct task_struct *tsk, unsigned long *sp,
-                                struct pt_regs *regs)
-{
-        unsigned long addr;
-
-        while (!kstack_end(sp)) {
-                addr = *sp++;
-                if (kernel_text_address(addr)) {
-                        printk(" [<%08lx>] ", addr);
-                        print_symbol("%s\n", addr);
-                }
-        }
-}
-#endif
-
-void show_trace(struct task_struct *tsk, unsigned long *sp,
-                       struct pt_regs *regs)
-{
-        if (regs &&
-            (((regs->sr & MODE_MASK) == MODE_EXCEPTION) ||
-             ((regs->sr & MODE_MASK) == MODE_USER)))
-                return;
-
-        printk ("Call trace:");
-#ifdef CONFIG_KALLSYMS
-        printk("\n");
-#endif
-
-        __show_trace(tsk, sp, regs);
-        printk("\n");
-}
-
-void show_stack(struct task_struct *tsk, unsigned long *sp)
-{
-        unsigned long stack;
-
-        if (!tsk)
-                tsk = current;
-        if (sp == 0) {
-                if (tsk == current) {
-                        register unsigned long *real_sp __asm__("sp");
-                        sp = real_sp;
-                } else {
-                        sp = (unsigned long *)tsk->thread.cpu_context.ksp;
-                }
-        }
-
-        stack = (unsigned long)sp;
-        dump_mem("Stack: ", stack,
-                 THREAD_SIZE + (unsigned long)tsk->thread_info);
-        show_trace(tsk, sp, NULL);
-}
-
-void dump_stack(void)
-{
-        show_stack(NULL, NULL);
-}
-EXPORT_SYMBOL(dump_stack);
+#include <asm/ocd.h>
+#include <asm/sysreg.h>
+#include <asm/traps.h>
 
 ATOMIC_NOTIFIER_HEAD(avr32_die_chain);
 
 int register_die_notifier(struct notifier_block *nb)
 {
-        pr_debug("register_die_notifier: %p\n", nb);
-
         return atomic_notifier_chain_register(&avr32_die_chain, nb);
 }
 EXPORT_SYMBOL(register_die_notifier);
@@ -169,93 +36,103 @@ EXPORT_SYMBOL(unregister_die_notifier);
 
 static DEFINE_SPINLOCK(die_lock);
 
-void __die(const char *str, struct pt_regs *regs, unsigned long err,
-           const char *file, const char *func, unsigned long line)
+void NORET_TYPE die(const char *str, struct pt_regs *regs, long err)
 {
-        struct task_struct *tsk = current;
         static int die_counter;
 
         console_verbose();
         spin_lock_irq(&die_lock);
         bust_spinlocks(1);
 
-        printk(KERN_ALERT "%s", str);
-        if (file && func)
-                printk(" in %s:%s, line %ld", file, func, line);
-        printk("[#%d]:\n", ++die_counter);
-        print_modules();
-        show_regs(regs);
-        printk("Process %s (pid: %d, stack limit = 0x%p)\n",
-               tsk->comm, tsk->pid, tsk->thread_info + 1);
-
-        if (!user_mode(regs) || in_interrupt()) {
-                dump_mem("Stack: ", regs->sp,
-                         THREAD_SIZE + (unsigned long)tsk->thread_info);
+        printk(KERN_ALERT "Oops: %s, sig: %ld [#%d]\n" KERN_EMERG,
+               str, err, ++die_counter);
+#ifdef CONFIG_PREEMPT
+        printk("PREEMPT ");
+#endif
+#ifdef CONFIG_FRAME_POINTER
+        printk("FRAME_POINTER ");
+#endif
+        if (current_cpu_data.features & AVR32_FEATURE_OCD) {
+                unsigned long did = __mfdr(DBGREG_DID);
+                printk("chip: 0x%03lx:0x%04lx rev %lu\n",
+                       (did >> 1) & 0x7ff,
+                       (did >> 12) & 0x7fff,
+                       (did >> 28) & 0xf);
+        } else {
+                printk("cpu: arch %u r%u / core %u r%u\n",
+                       current_cpu_data.arch_type,
+                       current_cpu_data.arch_revision,
+                       current_cpu_data.cpu_type,
+                       current_cpu_data.cpu_revision);
         }
 
+        print_modules();
+        show_regs_log_lvl(regs, KERN_EMERG);
+        show_stack_log_lvl(current, regs->sp, regs, KERN_EMERG);
         bust_spinlocks(0);
         spin_unlock_irq(&die_lock);
-        do_exit(SIGSEGV);
+
+        if (in_interrupt())
+                panic("Fatal exception in interrupt");
+
+        if (panic_on_oops)
+                panic("Fatal exception");
+
+        do_exit(err);
 }
 
-void __die_if_kernel(const char *str, struct pt_regs *regs, unsigned long err,
-                     const char *file, const char *func, unsigned long line)
+void _exception(long signr, struct pt_regs *regs, int code,
+                unsigned long addr)
 {
+        siginfo_t info;
+
         if (!user_mode(regs))
-                __die(str, regs, err, file, func, line);
-}
+                die("Unhandled exception in kernel mode", regs, signr);
+
+        memset(&info, 0, sizeof(info));
+        info.si_signo = signr;
+        info.si_code = code;
+        info.si_addr = (void __user *)addr;
+        force_sig_info(signr, &info, current);
 
-asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
-{
-#ifdef CONFIG_SUBARCH_AVR32B
         /*
-         * The exception entry always saves RSR_EX. For NMI, this is
-         * wrong; it should be RSR_NMI
+         * Init gets no signals that it doesn't have a handler for.
+         * That's all very well, but if it has caused a synchronous
+         * exception and we ignore the resulting signal, it will just
+         * generate the same exception over and over again and we get
+         * nowhere.  Better to kill it and let the kernel panic.
          */
-        regs->sr = sysreg_read(RSR_NMI);
-#endif
+        if (is_init(current)) {
+                __sighandler_t handler;
+
+                spin_lock_irq(&current->sighand->siglock);
+                handler = current->sighand->action[signr-1].sa.sa_handler;
+                spin_unlock_irq(&current->sighand->siglock);
+                if (handler == SIG_DFL) {
+                        /* init has generated a synchronous exception
+                           and it doesn't have a handler for the signal */
+                        printk(KERN_CRIT "init has generated signal %ld "
+                               "but has no handler for it\n", signr);
+                        do_exit(signr);
+                }
+        }
+}
 
-        printk("NMI taken!!!!\n");
-        die("NMI", regs, ecr);
-        BUG();
+asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
+{
+        printk(KERN_ALERT "Got Non-Maskable Interrupt, dumping regs\n");
+        show_regs_log_lvl(regs, KERN_ALERT);
+        show_stack_log_lvl(current, regs->sp, regs, KERN_ALERT);
 }
 
 asmlinkage void do_critical_exception(unsigned long ecr, struct pt_regs *regs)
 {
-        printk("Unable to handle critical exception %lu at pc = %08lx!\n",
-               ecr, regs->pc);
-        die("Oops", regs, ecr);
-        BUG();
+        die("Critical exception", regs, SIGKILL);
 }
 
 asmlinkage void do_address_exception(unsigned long ecr, struct pt_regs *regs)
 {
-        siginfo_t info;
-
-        die_if_kernel("Oops: Address exception in kernel mode", regs, ecr);
-
-#ifdef DEBUG
-        if (ecr == ECR_ADDR_ALIGN_X)
-                pr_debug("Instruction Address Exception at pc = %08lx\n",
-                         regs->pc);
-        else if (ecr == ECR_ADDR_ALIGN_R)
-                pr_debug("Data Address Exception (Read) at pc = %08lx\n",
-                         regs->pc);
-        else if (ecr == ECR_ADDR_ALIGN_W)
-                pr_debug("Data Address Exception (Write) at pc = %08lx\n",
-                         regs->pc);
-        else
-                BUG();
-
-        show_regs(regs);
-#endif
-
-        info.si_signo = SIGBUS;
-        info.si_errno = 0;
-        info.si_code = BUS_ADRALN;
-        info.si_addr = (void __user *)regs->pc;
-
-        force_sig_info(SIGBUS, &info, current);
+        _exception(SIGBUS, regs, BUS_ADRALN, regs->pc);
 }
 
 /* This way of handling undefined instructions is stolen from ARM */
@@ -280,7 +157,8 @@ static int do_cop_absent(u32 insn)
 {
         int cop_nr;
         u32 cpucr;
-        if ( (insn & 0xfdf00000) == 0xf1900000 )
+
+        if ((insn & 0xfdf00000) == 0xf1900000)
                 /* LDC0 */
                 cop_nr = 0;
         else
@@ -292,136 +170,91 @@ static int do_cop_absent(u32 insn)
         sysreg_write(CPUCR, cpucr);
 
         cpucr = sysreg_read(CPUCR);
-        if ( !(cpucr & (1 << (24 + cop_nr))) ){
-                printk("Coprocessor #%i not found!\n", cop_nr);
-                return -1;
-        }
+        if (!(cpucr & (1 << (24 + cop_nr))))
+                return -ENODEV;
 
         return 0;
 }
 
-#ifdef CONFIG_BUG
-#ifdef CONFIG_DEBUG_BUGVERBOSE
-static inline void do_bug_verbose(struct pt_regs *regs, u32 insn)
-{
-        char *file;
-        u16 line;
-        char c;
-
-        if (__get_user(line, (u16 __user *)(regs->pc + 2)))
-                return;
-        if (__get_user(file, (char * __user *)(regs->pc + 4))
-            || (unsigned long)file < PAGE_OFFSET
-            || __get_user(c, file))
-                file = "<bad filename>";
-
-        printk(KERN_ALERT "kernel BUG at %s:%d!\n", file, line);
-}
-#else
-static inline void do_bug_verbose(struct pt_regs *regs, u32 insn)
+int is_valid_bugaddr(unsigned long pc)
 {
+        unsigned short opcode;
+
+        if (pc < PAGE_OFFSET)
+                return 0;
+        if (probe_kernel_address((u16 *)pc, opcode))
+                return 0;
 
+        return opcode == AVR32_BUG_OPCODE;
 }
-#endif
-#endif
 
 asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
 {
         u32 insn;
         struct undef_hook *hook;
-        siginfo_t info;
         void __user *pc;
+        long code;
 
-        if (!user_mode(regs))
-                goto kernel_trap;
+        if (!user_mode(regs) && (ecr == ECR_ILLEGAL_OPCODE)) {
+                enum bug_trap_type type;
+
+                type = report_bug(regs->pc);
+                switch (type) {
+                case BUG_TRAP_TYPE_NONE:
+                        break;
+                case BUG_TRAP_TYPE_WARN:
+                        regs->pc += 2;
+                        return;
+                case BUG_TRAP_TYPE_BUG:
+                        die("Kernel BUG", regs, SIGKILL);
+                }
+        }
 
         local_irq_enable();
 
-        pc = (void __user *)instruction_pointer(regs);
-        if (__get_user(insn, (u32 __user *)pc))
-                goto invalid_area;
+        if (user_mode(regs)) {
+                pc = (void __user *)instruction_pointer(regs);
+                if (get_user(insn, (u32 __user *)pc))
+                        goto invalid_area;
 
-        if (ecr == ECR_COPROC_ABSENT) {
-                if (do_cop_absent(insn) == 0)
+                if (ecr == ECR_COPROC_ABSENT && !do_cop_absent(insn))
                         return;
-        }
 
-        spin_lock_irq(&undef_lock);
-        list_for_each_entry(hook, &undef_hook, node) {
-                if ((insn & hook->insn_mask) == hook->insn_val) {
-                        if (hook->fn(regs, insn) == 0) {
-                                spin_unlock_irq(&undef_lock);
-                                return;
+                spin_lock_irq(&undef_lock);
+                list_for_each_entry(hook, &undef_hook, node) {
+                        if ((insn & hook->insn_mask) == hook->insn_val) {
+                                if (hook->fn(regs, insn) == 0) {
+                                        spin_unlock_irq(&undef_lock);
+                                        return;
+                                }
                         }
                 }
+                spin_unlock_irq(&undef_lock);
         }
-        spin_unlock_irq(&undef_lock);
-
-invalid_area:
 
-#ifdef DEBUG
-        printk("Illegal instruction at pc = %08lx\n", regs->pc);
-        if (regs->pc < TASK_SIZE) {
-                unsigned long ptbr, pgd, pte, *p;
-
-                ptbr = sysreg_read(PTBR);
-                p = (unsigned long *)ptbr;
-                pgd = p[regs->pc >> 22];
-                p = (unsigned long *)((pgd & 0x1ffff000) | 0x80000000);
-                pte = p[(regs->pc >> 12) & 0x3ff];
-                printk("page table: 0x%08lx -> 0x%08lx -> 0x%08lx\n", ptbr, pgd, pte);
-        }
-#endif
-
-        info.si_signo = SIGILL;
-        info.si_errno = 0;
-        info.si_addr = (void __user *)regs->pc;
         switch (ecr) {
-        case ECR_ILLEGAL_OPCODE:
-        case ECR_UNIMPL_INSTRUCTION:
-                info.si_code = ILL_ILLOPC;
-                break;
         case ECR_PRIVILEGE_VIOLATION:
-                info.si_code = ILL_PRVOPC;
+                code = ILL_PRVOPC;
                 break;
         case ECR_COPROC_ABSENT:
-                info.si_code = ILL_COPROC;
+                code = ILL_COPROC;
                 break;
         default:
-                BUG();
+                code = ILL_ILLOPC;
+                break;
         }
 
-        force_sig_info(SIGILL, &info, current);
+        _exception(SIGILL, regs, code, regs->pc);
         return;
 
-kernel_trap:
-#ifdef CONFIG_BUG
-        if (__kernel_text_address(instruction_pointer(regs))) {
-                insn = *(u16 *)instruction_pointer(regs);
-                if (insn == AVR32_BUG_OPCODE) {
-                        do_bug_verbose(regs, insn);
-                        die("Kernel BUG", regs, 0);
-                        return;
-                }
-        }
-#endif
-
-        die("Oops: Illegal instruction in kernel code", regs, ecr);
+invalid_area:
+        _exception(SIGSEGV, regs, SEGV_MAPERR, regs->pc);
 }
 
 asmlinkage void do_fpe(unsigned long ecr, struct pt_regs *regs)
 {
-        siginfo_t info;
-
-        printk("Floating-point exception at pc = %08lx\n", regs->pc);
-
-        /* We have no FPU... */
-        info.si_signo = SIGILL;
-        info.si_errno = 0;
-        info.si_addr = (void __user *)regs->pc;
-        info.si_code = ILL_COPROC;
-
-        force_sig_info(SIGILL, &info, current);
+        /* We have no FPU yet */
+        _exception(SIGILL, regs, ILL_COPROC, regs->pc);
 }
 
 
diff --git a/arch/avr32/kernel/vmlinux.lds.c b/arch/avr32/kernel/vmlinux.lds.c
index ef13b7c78935..7ad20cfb48a8 100644
--- a/arch/avr32/kernel/vmlinux.lds.c
+++ b/arch/avr32/kernel/vmlinux.lds.c
@@ -26,6 +26,12 @@ SECTIONS
                         _sinittext = .;
                         *(.text.reset)
                         *(.init.text)
+                        /*
+                         * .exit.text is discarded at runtime, not
+                         * link time, to deal with references from
+                         * __bug_table
+                         */
+                        *(.exit.text)
                         _einittext = .;
                 . = ALIGN(4);
                 __tagtable_begin = .;
@@ -86,6 +92,8 @@ SECTIONS
                 __stop___ex_table = .;
         }
 
+        BUG_TABLE
+
         RODATA
 
         . = ALIGN(8192);
@@ -126,7 +134,6 @@ SECTIONS
          * thrown away, as cleanup code is never called unless it's a module.
          */
         /DISCARD/               : {
-                *(.exit.text)
                 *(.exit.data)
                 *(.exitcall.exit)
         }
diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
index 678557260a35..146ebdbdc302 100644
--- a/arch/avr32/mm/fault.c
+++ b/arch/avr32/mm/fault.c
@@ -16,26 +16,8 @@
 #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
+#include <asm/uaccess.h>
 
 #ifdef CONFIG_KPROBES
 ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
@@ -68,17 +50,19 @@ static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
 }
 #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:
- *   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)
+ *   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)
 {
@@ -88,7 +72,9 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
         const struct exception_table_entry *fixup;
         unsigned long address;
         unsigned long page;
-        int writeaccess = 0;
+        int writeaccess;
+        long signr;
+        int code;
 
         if (notify_page_fault(DIE_PAGE_FAULT, regs,
                               ecr, SIGSEGV) == NOTIFY_STOP)
@@ -99,6 +85,9 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
         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...
@@ -125,7 +114,9 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
          * can handle it...
          */
 good_area:
-        //pr_debug("good area: vm_flags = 0x%lx\n", vma->vm_flags);
+        code = SEGV_ACCERR;
+        writeaccess = 0;
+
         switch (ecr) {
         case ECR_PROTECTION_X:
         case ECR_TLB_MISS_X:
@@ -176,46 +167,24 @@ survive:
          * 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);
+                if (exception_trace)
+                        printk("%s%s[%d]: segfault at %08lx pc %08lx "
+                               "sp %08lx ecr %lu\n",
+                               is_init(tsk) ? KERN_EMERG : KERN_INFO,
+                               tsk->comm, tsk->pid, address, regs->pc,
+                               regs->sp, ecr);
+                _exception(SIGSEGV, regs, code, address);
                 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;
         }
 
@@ -230,7 +199,6 @@ no_context:
                 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);
@@ -241,20 +209,20 @@ no_context:
                         page &= PAGE_MASK;
                         address &= 0x003ff000;
                         page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT];
-                        printk(" pte = %08lx\n", page);
+                        printk(" pte = %08lx", page);
                 }
         }
-        die("\nOops", regs, ecr);
-        do_exit(SIGKILL);
+        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:
-        printk("Out of memory\n");
         up_read(&mm->mmap_sem);
-        if (current->pid == 1) {
+        if (is_init(current)) {
                 yield();
                 down_read(&mm->mmap_sem);
                 goto survive;
@@ -267,21 +235,20 @@ out_of_memory:
 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 */
+        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_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,
@@ -292,8 +259,7 @@ asmlinkage void do_bus_error(unsigned long addr, int write_access,
                addr, write_access ? "write" : "read");
         printk(KERN_INFO "DTLB dump:\n");
         dump_dtlb();
-        die("Bus Error", regs, write_access);
-        do_exit(SIGKILL);
+        die("Bus Error", regs, SIGKILL);
 }
 
 /*