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3338368e92
Terminate the frame pointer walk if (a) the address is outside the task's kernel stack or (b) if the frame pointer isn't monotonically increasing. Without this fix, show_trace() may enter an infinite loop, walking through random data anywhere in memory. Since any address within the kernel stack is guaranteed to be valid, we may eliminate the __get_user() calls as well. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
432 lines
9.1 KiB
C
432 lines
9.1 KiB
C
/*
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* Copyright (C) 2004-2006 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#undef DEBUG
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/notifier.h>
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#include <asm/traps.h>
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#include <asm/sysreg.h>
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#include <asm/addrspace.h>
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#include <asm/ocd.h>
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#include <asm/mmu_context.h>
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#include <asm/uaccess.h>
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static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
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{
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unsigned long p;
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int i;
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printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
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for (p = bottom & ~31; p < top; ) {
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printk("%04lx: ", p & 0xffff);
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for (i = 0; i < 8; i++, p += 4) {
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unsigned int val;
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if (p < bottom || p >= top)
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printk(" ");
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else {
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if (__get_user(val, (unsigned int __user *)p)) {
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printk("\n");
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goto out;
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}
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printk("%08x ", val);
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}
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}
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printk("\n");
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}
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out:
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return;
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}
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static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
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{
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return (p > (unsigned long)tinfo)
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&& (p < (unsigned long)tinfo + THREAD_SIZE - 3);
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}
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#ifdef CONFIG_FRAME_POINTER
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static inline void __show_trace(struct task_struct *tsk, unsigned long *sp,
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struct pt_regs *regs)
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{
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unsigned long lr, fp;
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struct thread_info *tinfo;
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tinfo = (struct thread_info *)
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((unsigned long)sp & ~(THREAD_SIZE - 1));
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if (regs)
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fp = regs->r7;
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else if (tsk == current)
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asm("mov %0, r7" : "=r"(fp));
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else
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fp = tsk->thread.cpu_context.r7;
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/*
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* Walk the stack as long as the frame pointer (a) is within
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* the kernel stack of the task, and (b) it doesn't move
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* downwards.
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*/
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while (valid_stack_ptr(tinfo, fp)) {
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unsigned long new_fp;
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lr = *(unsigned long *)fp;
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printk(" [<%08lx>] ", lr);
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print_symbol("%s\n", lr);
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new_fp = *(unsigned long *)(fp + 4);
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if (new_fp <= fp)
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break;
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fp = new_fp;
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}
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printk("\n");
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}
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#else
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static inline void __show_trace(struct task_struct *tsk, unsigned long *sp,
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struct pt_regs *regs)
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{
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unsigned long addr;
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while (!kstack_end(sp)) {
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addr = *sp++;
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if (kernel_text_address(addr)) {
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printk(" [<%08lx>] ", addr);
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print_symbol("%s\n", addr);
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}
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}
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}
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#endif
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void show_trace(struct task_struct *tsk, unsigned long *sp,
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struct pt_regs *regs)
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{
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if (regs &&
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(((regs->sr & MODE_MASK) == MODE_EXCEPTION) ||
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((regs->sr & MODE_MASK) == MODE_USER)))
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return;
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printk ("Call trace:");
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#ifdef CONFIG_KALLSYMS
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printk("\n");
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#endif
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__show_trace(tsk, sp, regs);
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printk("\n");
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}
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void show_stack(struct task_struct *tsk, unsigned long *sp)
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{
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unsigned long stack;
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if (!tsk)
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tsk = current;
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if (sp == 0) {
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if (tsk == current) {
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register unsigned long *real_sp __asm__("sp");
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sp = real_sp;
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} else {
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sp = (unsigned long *)tsk->thread.cpu_context.ksp;
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}
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}
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stack = (unsigned long)sp;
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dump_mem("Stack: ", stack,
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THREAD_SIZE + (unsigned long)tsk->thread_info);
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show_trace(tsk, sp, NULL);
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}
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void dump_stack(void)
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{
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show_stack(NULL, NULL);
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}
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EXPORT_SYMBOL(dump_stack);
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ATOMIC_NOTIFIER_HEAD(avr32_die_chain);
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int register_die_notifier(struct notifier_block *nb)
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{
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pr_debug("register_die_notifier: %p\n", nb);
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return atomic_notifier_chain_register(&avr32_die_chain, nb);
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}
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EXPORT_SYMBOL(register_die_notifier);
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int unregister_die_notifier(struct notifier_block *nb)
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{
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return atomic_notifier_chain_unregister(&avr32_die_chain, nb);
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}
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EXPORT_SYMBOL(unregister_die_notifier);
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static DEFINE_SPINLOCK(die_lock);
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void __die(const char *str, struct pt_regs *regs, unsigned long err,
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const char *file, const char *func, unsigned long line)
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{
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struct task_struct *tsk = current;
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static int die_counter;
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console_verbose();
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spin_lock_irq(&die_lock);
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bust_spinlocks(1);
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printk(KERN_ALERT "%s", str);
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if (file && func)
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printk(" in %s:%s, line %ld", file, func, line);
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printk("[#%d]:\n", ++die_counter);
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print_modules();
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show_regs(regs);
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printk("Process %s (pid: %d, stack limit = 0x%p)\n",
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tsk->comm, tsk->pid, tsk->thread_info + 1);
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if (!user_mode(regs) || in_interrupt()) {
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dump_mem("Stack: ", regs->sp,
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THREAD_SIZE + (unsigned long)tsk->thread_info);
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}
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bust_spinlocks(0);
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spin_unlock_irq(&die_lock);
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do_exit(SIGSEGV);
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}
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void __die_if_kernel(const char *str, struct pt_regs *regs, unsigned long err,
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const char *file, const char *func, unsigned long line)
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{
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if (!user_mode(regs))
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__die(str, regs, err, file, func, line);
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}
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asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
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{
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#ifdef CONFIG_SUBARCH_AVR32B
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/*
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* The exception entry always saves RSR_EX. For NMI, this is
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* wrong; it should be RSR_NMI
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*/
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regs->sr = sysreg_read(RSR_NMI);
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#endif
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printk("NMI taken!!!!\n");
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die("NMI", regs, ecr);
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BUG();
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}
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asmlinkage void do_critical_exception(unsigned long ecr, struct pt_regs *regs)
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{
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printk("Unable to handle critical exception %lu at pc = %08lx!\n",
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ecr, regs->pc);
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die("Oops", regs, ecr);
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BUG();
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}
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asmlinkage void do_address_exception(unsigned long ecr, struct pt_regs *regs)
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{
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siginfo_t info;
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die_if_kernel("Oops: Address exception in kernel mode", regs, ecr);
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#ifdef DEBUG
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if (ecr == ECR_ADDR_ALIGN_X)
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pr_debug("Instruction Address Exception at pc = %08lx\n",
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regs->pc);
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else if (ecr == ECR_ADDR_ALIGN_R)
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pr_debug("Data Address Exception (Read) at pc = %08lx\n",
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regs->pc);
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else if (ecr == ECR_ADDR_ALIGN_W)
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pr_debug("Data Address Exception (Write) at pc = %08lx\n",
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regs->pc);
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else
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BUG();
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show_regs(regs);
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#endif
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info.si_signo = SIGBUS;
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info.si_errno = 0;
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info.si_code = BUS_ADRALN;
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info.si_addr = (void __user *)regs->pc;
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force_sig_info(SIGBUS, &info, current);
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}
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/* This way of handling undefined instructions is stolen from ARM */
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static LIST_HEAD(undef_hook);
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static spinlock_t undef_lock = SPIN_LOCK_UNLOCKED;
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void register_undef_hook(struct undef_hook *hook)
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{
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spin_lock_irq(&undef_lock);
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list_add(&hook->node, &undef_hook);
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spin_unlock_irq(&undef_lock);
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}
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void unregister_undef_hook(struct undef_hook *hook)
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{
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spin_lock_irq(&undef_lock);
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list_del(&hook->node);
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spin_unlock_irq(&undef_lock);
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}
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static int do_cop_absent(u32 insn)
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{
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int cop_nr;
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u32 cpucr;
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if ( (insn & 0xfdf00000) == 0xf1900000 )
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/* LDC0 */
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cop_nr = 0;
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else
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cop_nr = (insn >> 13) & 0x7;
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/* Try enabling the coprocessor */
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cpucr = sysreg_read(CPUCR);
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cpucr |= (1 << (24 + cop_nr));
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sysreg_write(CPUCR, cpucr);
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cpucr = sysreg_read(CPUCR);
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if ( !(cpucr & (1 << (24 + cop_nr))) ){
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printk("Coprocessor #%i not found!\n", cop_nr);
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return -1;
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}
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return 0;
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}
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#ifdef CONFIG_BUG
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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static inline void do_bug_verbose(struct pt_regs *regs, u32 insn)
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{
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char *file;
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u16 line;
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char c;
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if (__get_user(line, (u16 __user *)(regs->pc + 2)))
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return;
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if (__get_user(file, (char * __user *)(regs->pc + 4))
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|| (unsigned long)file < PAGE_OFFSET
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|| __get_user(c, file))
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file = "<bad filename>";
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printk(KERN_ALERT "kernel BUG at %s:%d!\n", file, line);
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}
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#else
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static inline void do_bug_verbose(struct pt_regs *regs, u32 insn)
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{
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}
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#endif
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#endif
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asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
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{
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u32 insn;
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struct undef_hook *hook;
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siginfo_t info;
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void __user *pc;
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if (!user_mode(regs))
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goto kernel_trap;
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local_irq_enable();
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pc = (void __user *)instruction_pointer(regs);
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if (__get_user(insn, (u32 __user *)pc))
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goto invalid_area;
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if (ecr == ECR_COPROC_ABSENT) {
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if (do_cop_absent(insn) == 0)
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return;
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}
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spin_lock_irq(&undef_lock);
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list_for_each_entry(hook, &undef_hook, node) {
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if ((insn & hook->insn_mask) == hook->insn_val) {
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if (hook->fn(regs, insn) == 0) {
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spin_unlock_irq(&undef_lock);
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return;
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}
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}
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}
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spin_unlock_irq(&undef_lock);
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invalid_area:
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#ifdef DEBUG
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printk("Illegal instruction at pc = %08lx\n", regs->pc);
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if (regs->pc < TASK_SIZE) {
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unsigned long ptbr, pgd, pte, *p;
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ptbr = sysreg_read(PTBR);
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p = (unsigned long *)ptbr;
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pgd = p[regs->pc >> 22];
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p = (unsigned long *)((pgd & 0x1ffff000) | 0x80000000);
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pte = p[(regs->pc >> 12) & 0x3ff];
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printk("page table: 0x%08lx -> 0x%08lx -> 0x%08lx\n", ptbr, pgd, pte);
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}
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#endif
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info.si_signo = SIGILL;
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info.si_errno = 0;
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info.si_addr = (void __user *)regs->pc;
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switch (ecr) {
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case ECR_ILLEGAL_OPCODE:
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case ECR_UNIMPL_INSTRUCTION:
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info.si_code = ILL_ILLOPC;
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break;
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case ECR_PRIVILEGE_VIOLATION:
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info.si_code = ILL_PRVOPC;
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break;
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case ECR_COPROC_ABSENT:
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info.si_code = ILL_COPROC;
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break;
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default:
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BUG();
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}
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force_sig_info(SIGILL, &info, current);
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return;
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kernel_trap:
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#ifdef CONFIG_BUG
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if (__kernel_text_address(instruction_pointer(regs))) {
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insn = *(u16 *)instruction_pointer(regs);
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if (insn == AVR32_BUG_OPCODE) {
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do_bug_verbose(regs, insn);
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die("Kernel BUG", regs, 0);
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return;
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}
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}
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#endif
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die("Oops: Illegal instruction in kernel code", regs, ecr);
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}
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asmlinkage void do_fpe(unsigned long ecr, struct pt_regs *regs)
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{
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siginfo_t info;
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printk("Floating-point exception at pc = %08lx\n", regs->pc);
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/* We have no FPU... */
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info.si_signo = SIGILL;
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info.si_errno = 0;
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info.si_addr = (void __user *)regs->pc;
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info.si_code = ILL_COPROC;
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force_sig_info(SIGILL, &info, current);
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}
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void __init trap_init(void)
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{
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}
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