455 lines
10 KiB
C
455 lines
10 KiB
C
/*
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* Kernel traps/events for Hexagon processor
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*
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* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
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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 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/kdebug.h>
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#include <linux/syscalls.h>
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#include <linux/signal.h>
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#include <linux/tracehook.h>
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#include <asm/traps.h>
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#include <asm/vm_fault.h>
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#include <asm/syscall.h>
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#include <asm/registers.h>
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#include <asm/unistd.h>
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#include <asm/sections.h>
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#ifdef CONFIG_KGDB
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# include <linux/kgdb.h>
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#endif
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#define TRAP_SYSCALL 1
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#define TRAP_DEBUG 0xdb
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void __init trap_init(void)
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{
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}
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#ifdef CONFIG_GENERIC_BUG
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/* Maybe should resemble arch/sh/kernel/traps.c ?? */
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int is_valid_bugaddr(unsigned long addr)
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{
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return 1;
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}
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#endif /* CONFIG_GENERIC_BUG */
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static const char *ex_name(int ex)
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{
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switch (ex) {
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case HVM_GE_C_XPROT:
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case HVM_GE_C_XUSER:
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return "Execute protection fault";
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case HVM_GE_C_RPROT:
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case HVM_GE_C_RUSER:
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return "Read protection fault";
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case HVM_GE_C_WPROT:
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case HVM_GE_C_WUSER:
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return "Write protection fault";
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case HVM_GE_C_XMAL:
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return "Misaligned instruction";
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case HVM_GE_C_RMAL:
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return "Misaligned data load";
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case HVM_GE_C_WMAL:
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return "Misaligned data store";
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case HVM_GE_C_INVI:
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case HVM_GE_C_PRIVI:
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return "Illegal instruction";
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case HVM_GE_C_BUS:
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return "Precise bus error";
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case HVM_GE_C_CACHE:
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return "Cache error";
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case 0xdb:
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return "Debugger trap";
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default:
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return "Unrecognized exception";
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}
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}
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static void do_show_stack(struct task_struct *task, unsigned long *fp,
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unsigned long ip)
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{
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int kstack_depth_to_print = 24;
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unsigned long offset, size;
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const char *name = NULL;
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unsigned long *newfp;
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unsigned long low, high;
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char tmpstr[128];
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char *modname;
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int i;
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if (task == NULL)
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task = current;
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printk(KERN_INFO "CPU#%d, %s/%d, Call Trace:\n",
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raw_smp_processor_id(), task->comm,
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task_pid_nr(task));
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if (fp == NULL) {
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if (task == current) {
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asm("%0 = r30" : "=r" (fp));
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} else {
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fp = (unsigned long *)
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((struct hexagon_switch_stack *)
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task->thread.switch_sp)->fp;
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}
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}
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if ((((unsigned long) fp) & 0x3) || ((unsigned long) fp < 0x1000)) {
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printk(KERN_INFO "-- Corrupt frame pointer %p\n", fp);
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return;
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}
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/* Saved link reg is one word above FP */
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if (!ip)
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ip = *(fp+1);
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/* Expect kernel stack to be in-bounds */
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low = (unsigned long)task_stack_page(task);
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high = low + THREAD_SIZE - 8;
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low += sizeof(struct thread_info);
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for (i = 0; i < kstack_depth_to_print; i++) {
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name = kallsyms_lookup(ip, &size, &offset, &modname, tmpstr);
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printk(KERN_INFO "[%p] 0x%lx: %s + 0x%lx", fp, ip, name,
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offset);
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if (((unsigned long) fp < low) || (high < (unsigned long) fp))
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printk(KERN_CONT " (FP out of bounds!)");
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if (modname)
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printk(KERN_CONT " [%s] ", modname);
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printk(KERN_CONT "\n");
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newfp = (unsigned long *) *fp;
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if (((unsigned long) newfp) & 0x3) {
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printk(KERN_INFO "-- Corrupt frame pointer %p\n",
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newfp);
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break;
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}
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/* Attempt to continue past exception. */
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if (0 == newfp) {
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struct pt_regs *regs = (struct pt_regs *) (((void *)fp)
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+ 8);
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if (regs->syscall_nr != -1) {
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printk(KERN_INFO "-- trap0 -- syscall_nr: %ld",
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regs->syscall_nr);
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printk(KERN_CONT " psp: %lx elr: %lx\n",
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pt_psp(regs), pt_elr(regs));
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break;
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} else {
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/* really want to see more ... */
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kstack_depth_to_print += 6;
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printk(KERN_INFO "-- %s (0x%lx) badva: %lx\n",
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ex_name(pt_cause(regs)), pt_cause(regs),
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pt_badva(regs));
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}
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newfp = (unsigned long *) regs->r30;
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ip = pt_elr(regs);
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} else {
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ip = *(newfp + 1);
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}
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/* If link reg is null, we are done. */
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if (ip == 0x0)
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break;
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/* If newfp isn't larger, we're tracing garbage. */
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if (newfp > fp)
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fp = newfp;
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else
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break;
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}
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}
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void show_stack(struct task_struct *task, unsigned long *fp)
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{
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/* Saved link reg is one word above FP */
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do_show_stack(task, fp, 0);
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}
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void dump_stack(void)
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{
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unsigned long *fp;
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asm("%0 = r30" : "=r" (fp));
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show_stack(current, fp);
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}
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EXPORT_SYMBOL(dump_stack);
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int die(const char *str, struct pt_regs *regs, long err)
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{
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static struct {
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spinlock_t lock;
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int counter;
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} die = {
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.lock = __SPIN_LOCK_UNLOCKED(die.lock),
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.counter = 0
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};
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console_verbose();
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oops_enter();
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spin_lock_irq(&die.lock);
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bust_spinlocks(1);
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printk(KERN_EMERG "Oops: %s[#%d]:\n", str, ++die.counter);
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if (notify_die(DIE_OOPS, str, regs, err, pt_cause(regs), SIGSEGV) ==
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NOTIFY_STOP)
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return 1;
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print_modules();
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show_regs(regs);
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do_show_stack(current, ®s->r30, pt_elr(regs));
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bust_spinlocks(0);
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add_taint(TAINT_DIE);
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spin_unlock_irq(&die.lock);
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if (in_interrupt())
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panic("Fatal exception in interrupt");
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if (panic_on_oops)
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panic("Fatal exception");
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oops_exit();
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do_exit(err);
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return 0;
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}
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int die_if_kernel(char *str, struct pt_regs *regs, long err)
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{
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if (!user_mode(regs))
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return die(str, regs, err);
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else
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return 0;
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}
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/*
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* It's not clear that misaligned fetches are ever recoverable.
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*/
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static void misaligned_instruction(struct pt_regs *regs)
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{
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die_if_kernel("Misaligned Instruction", regs, 0);
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force_sig(SIGBUS, current);
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}
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/*
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* Misaligned loads and stores, on the other hand, can be
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* emulated, and probably should be, some day. But for now
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* they will be considered fatal.
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*/
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static void misaligned_data_load(struct pt_regs *regs)
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{
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die_if_kernel("Misaligned Data Load", regs, 0);
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force_sig(SIGBUS, current);
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}
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static void misaligned_data_store(struct pt_regs *regs)
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{
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die_if_kernel("Misaligned Data Store", regs, 0);
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force_sig(SIGBUS, current);
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}
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static void illegal_instruction(struct pt_regs *regs)
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{
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die_if_kernel("Illegal Instruction", regs, 0);
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force_sig(SIGILL, current);
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}
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/*
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* Precise bus errors may be recoverable with a a retry,
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* but for now, treat them as irrecoverable.
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*/
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static void precise_bus_error(struct pt_regs *regs)
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{
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die_if_kernel("Precise Bus Error", regs, 0);
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force_sig(SIGBUS, current);
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}
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/*
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* If anything is to be done here other than panic,
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* it will probably be complex and migrate to another
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* source module. For now, just die.
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*/
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static void cache_error(struct pt_regs *regs)
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{
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die("Cache Error", regs, 0);
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}
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/*
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* General exception handler
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*/
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void do_genex(struct pt_regs *regs)
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{
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/*
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* Decode Cause and Dispatch
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*/
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switch (pt_cause(regs)) {
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case HVM_GE_C_XPROT:
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case HVM_GE_C_XUSER:
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execute_protection_fault(regs);
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break;
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case HVM_GE_C_RPROT:
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case HVM_GE_C_RUSER:
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read_protection_fault(regs);
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break;
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case HVM_GE_C_WPROT:
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case HVM_GE_C_WUSER:
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write_protection_fault(regs);
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break;
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case HVM_GE_C_XMAL:
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misaligned_instruction(regs);
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break;
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case HVM_GE_C_RMAL:
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misaligned_data_load(regs);
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break;
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case HVM_GE_C_WMAL:
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misaligned_data_store(regs);
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break;
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case HVM_GE_C_INVI:
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case HVM_GE_C_PRIVI:
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illegal_instruction(regs);
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break;
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case HVM_GE_C_BUS:
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precise_bus_error(regs);
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break;
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case HVM_GE_C_CACHE:
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cache_error(regs);
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break;
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default:
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/* Halt and catch fire */
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panic("Unrecognized exception 0x%lx\n", pt_cause(regs));
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break;
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}
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}
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/* Indirect system call dispatch */
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long sys_syscall(void)
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{
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printk(KERN_ERR "sys_syscall invoked!\n");
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return -ENOSYS;
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}
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void do_trap0(struct pt_regs *regs)
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{
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unsigned long syscallret = 0;
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syscall_fn syscall;
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switch (pt_cause(regs)) {
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case TRAP_SYSCALL:
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/* System call is trap0 #1 */
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/* allow strace to catch syscall args */
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if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE) &&
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tracehook_report_syscall_entry(regs)))
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return; /* return -ENOSYS somewhere? */
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/* Interrupts should be re-enabled for syscall processing */
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__vmsetie(VM_INT_ENABLE);
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/*
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* System call number is in r6, arguments in r0..r5.
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* Fortunately, no Linux syscall has more than 6 arguments,
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* and Hexagon ABI passes first 6 arguments in registers.
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* 64-bit arguments are passed in odd/even register pairs.
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* Fortunately, we have no system calls that take more
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* than three arguments with more than one 64-bit value.
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* Should that change, we'd need to redesign to copy
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* between user and kernel stacks.
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*/
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regs->syscall_nr = regs->r06;
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/*
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* GPR R0 carries the first parameter, and is also used
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* to report the return value. We need a backup of
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* the user's value in case we need to do a late restart
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* of the system call.
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*/
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regs->restart_r0 = regs->r00;
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if ((unsigned long) regs->syscall_nr >= __NR_syscalls) {
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regs->r00 = -1;
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} else {
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syscall = (syscall_fn)
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(sys_call_table[regs->syscall_nr]);
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syscallret = syscall(regs->r00, regs->r01,
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regs->r02, regs->r03,
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regs->r04, regs->r05);
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}
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/*
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* If it was a sigreturn system call, don't overwrite
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* r0 value in stack frame with return value.
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*
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* __NR_sigreturn doesn't seem to exist in new unistd.h
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*/
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if (regs->syscall_nr != __NR_rt_sigreturn)
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regs->r00 = syscallret;
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/* allow strace to get the syscall return state */
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if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE)))
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tracehook_report_syscall_exit(regs, 0);
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break;
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case TRAP_DEBUG:
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/* Trap0 0xdb is debug breakpoint */
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if (user_mode(regs)) {
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struct siginfo info;
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info.si_signo = SIGTRAP;
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info.si_errno = 0;
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/*
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* Some architecures add some per-thread state
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* to distinguish between breakpoint traps and
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* trace traps. We may want to do that, and
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* set the si_code value appropriately, or we
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* may want to use a different trap0 flavor.
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*/
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info.si_code = TRAP_BRKPT;
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info.si_addr = (void __user *) pt_elr(regs);
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send_sig_info(SIGTRAP, &info, current);
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} else {
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#ifdef CONFIG_KGDB
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kgdb_handle_exception(pt_cause(regs), SIGTRAP,
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TRAP_BRKPT, regs);
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#endif
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}
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break;
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}
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/* Ignore other trap0 codes for now, especially 0 (Angel calls) */
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}
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/*
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* Machine check exception handler
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*/
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void do_machcheck(struct pt_regs *regs)
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{
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/* Halt and catch fire */
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__vmstop();
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}
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