![Catalin Marinas](/assets/img/avatar_default.png)
The patch contains the exception entry code (kernel/entry.S), pt_regs structure and related accessors, undefined instruction trapping and stack tracing. AArch64 Linux kernel (including kernel threads) runs in EL1 mode using the SP1 stack. The vectors don't have a fixed address, only alignment (2^11) requirements. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
349 lines
7.7 KiB
C
349 lines
7.7 KiB
C
/*
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* Based on arch/arm/kernel/traps.c
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*
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* Copyright (C) 1995-2009 Russell King
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* Copyright (C) 2012 ARM Ltd.
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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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* 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, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/signal.h>
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#include <linux/personality.h>
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#include <linux/kallsyms.h>
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#include <linux/spinlock.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <linux/kdebug.h>
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#include <linux/module.h>
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#include <linux/kexec.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/syscalls.h>
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#include <asm/atomic.h>
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#include <asm/traps.h>
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#include <asm/stacktrace.h>
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#include <asm/exception.h>
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#include <asm/system_misc.h>
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static const char *handler[]= {
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"Synchronous Abort",
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"IRQ",
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"FIQ",
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"Error"
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};
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int show_unhandled_signals = 1;
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/*
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* Dump out the contents of some memory nicely...
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*/
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static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
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unsigned long top)
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{
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unsigned long first;
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mm_segment_t fs;
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int i;
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/*
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* We need to switch to kernel mode so that we can use __get_user
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* to safely read from kernel space. Note that we now dump the
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* code first, just in case the backtrace kills us.
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*/
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fs = get_fs();
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set_fs(KERNEL_DS);
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printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
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for (first = bottom & ~31; first < top; first += 32) {
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unsigned long p;
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char str[sizeof(" 12345678") * 8 + 1];
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memset(str, ' ', sizeof(str));
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str[sizeof(str) - 1] = '\0';
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for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
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if (p >= bottom && p < top) {
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unsigned int val;
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if (__get_user(val, (unsigned int *)p) == 0)
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sprintf(str + i * 9, " %08x", val);
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else
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sprintf(str + i * 9, " ????????");
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}
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}
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printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
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}
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set_fs(fs);
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}
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static void dump_backtrace_entry(unsigned long where, unsigned long stack)
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{
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print_ip_sym(where);
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if (in_exception_text(where))
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dump_mem("", "Exception stack", stack,
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stack + sizeof(struct pt_regs));
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}
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static void dump_instr(const char *lvl, struct pt_regs *regs)
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{
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unsigned long addr = instruction_pointer(regs);
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mm_segment_t fs;
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char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
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int i;
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/*
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* We need to switch to kernel mode so that we can use __get_user
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* to safely read from kernel space. Note that we now dump the
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* code first, just in case the backtrace kills us.
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*/
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fs = get_fs();
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set_fs(KERNEL_DS);
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for (i = -4; i < 1; i++) {
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unsigned int val, bad;
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bad = __get_user(val, &((u32 *)addr)[i]);
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if (!bad)
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p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
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else {
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p += sprintf(p, "bad PC value");
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break;
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}
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}
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printk("%sCode: %s\n", lvl, str);
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set_fs(fs);
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}
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static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
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{
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struct stackframe frame;
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const register unsigned long current_sp asm ("sp");
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pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
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if (!tsk)
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tsk = current;
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if (regs) {
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frame.fp = regs->regs[29];
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frame.sp = regs->sp;
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frame.pc = regs->pc;
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} else if (tsk == current) {
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frame.fp = (unsigned long)__builtin_frame_address(0);
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frame.sp = current_sp;
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frame.pc = (unsigned long)dump_backtrace;
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} else {
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/*
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* task blocked in __switch_to
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*/
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frame.fp = thread_saved_fp(tsk);
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frame.sp = thread_saved_sp(tsk);
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frame.pc = thread_saved_pc(tsk);
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}
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printk("Call trace:\n");
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while (1) {
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unsigned long where = frame.pc;
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int ret;
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ret = unwind_frame(&frame);
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if (ret < 0)
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break;
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dump_backtrace_entry(where, frame.sp);
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}
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}
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void dump_stack(void)
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{
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dump_backtrace(NULL, NULL);
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}
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EXPORT_SYMBOL(dump_stack);
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void show_stack(struct task_struct *tsk, unsigned long *sp)
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{
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dump_backtrace(NULL, tsk);
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barrier();
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}
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#ifdef CONFIG_PREEMPT
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#define S_PREEMPT " PREEMPT"
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#else
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#define S_PREEMPT ""
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#endif
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#ifdef CONFIG_SMP
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#define S_SMP " SMP"
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#else
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#define S_SMP ""
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#endif
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static int __die(const char *str, int err, struct thread_info *thread,
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struct pt_regs *regs)
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{
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struct task_struct *tsk = thread->task;
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static int die_counter;
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int ret;
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pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
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str, err, ++die_counter);
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/* trap and error numbers are mostly meaningless on ARM */
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ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
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if (ret == NOTIFY_STOP)
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return ret;
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print_modules();
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__show_regs(regs);
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pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
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TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
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if (!user_mode(regs) || in_interrupt()) {
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dump_mem(KERN_EMERG, "Stack: ", regs->sp,
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THREAD_SIZE + (unsigned long)task_stack_page(tsk));
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dump_backtrace(regs, tsk);
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dump_instr(KERN_EMERG, regs);
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}
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return ret;
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}
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static DEFINE_RAW_SPINLOCK(die_lock);
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/*
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* This function is protected against re-entrancy.
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*/
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void die(const char *str, struct pt_regs *regs, int err)
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{
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struct thread_info *thread = current_thread_info();
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int ret;
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oops_enter();
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raw_spin_lock_irq(&die_lock);
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console_verbose();
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bust_spinlocks(1);
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ret = __die(str, err, thread, regs);
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if (regs && kexec_should_crash(thread->task))
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crash_kexec(regs);
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bust_spinlocks(0);
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add_taint(TAINT_DIE);
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raw_spin_unlock_irq(&die_lock);
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oops_exit();
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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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if (ret != NOTIFY_STOP)
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do_exit(SIGSEGV);
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}
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void arm64_notify_die(const char *str, struct pt_regs *regs,
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struct siginfo *info, int err)
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{
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if (user_mode(regs))
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force_sig_info(info->si_signo, info, current);
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else
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die(str, regs, err);
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}
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asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
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{
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siginfo_t info;
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void __user *pc = (void __user *)instruction_pointer(regs);
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#ifdef CONFIG_COMPAT
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/* check for AArch32 breakpoint instructions */
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if (compat_user_mode(regs) && aarch32_break_trap(regs) == 0)
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return;
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#endif
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if (show_unhandled_signals) {
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pr_info("%s[%d]: undefined instruction: pc=%p\n",
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current->comm, task_pid_nr(current), pc);
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dump_instr(KERN_INFO, regs);
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}
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info.si_signo = SIGILL;
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info.si_errno = 0;
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info.si_code = ILL_ILLOPC;
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info.si_addr = pc;
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arm64_notify_die("Oops - undefined instruction", regs, &info, 0);
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}
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long compat_arm_syscall(struct pt_regs *regs);
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asmlinkage long do_ni_syscall(struct pt_regs *regs)
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{
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#ifdef CONFIG_COMPAT
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long ret;
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if (is_compat_task()) {
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ret = compat_arm_syscall(regs);
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if (ret != -ENOSYS)
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return ret;
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}
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#endif
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if (show_unhandled_signals) {
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pr_info("%s[%d]: syscall %d\n", current->comm,
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task_pid_nr(current), (int)regs->syscallno);
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dump_instr("", regs);
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if (user_mode(regs))
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__show_regs(regs);
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}
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return sys_ni_syscall();
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}
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/*
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* bad_mode handles the impossible case in the exception vector.
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*/
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asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
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{
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console_verbose();
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pr_crit("Bad mode in %s handler detected, code 0x%08x\n",
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handler[reason], esr);
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die("Oops - bad mode", regs, 0);
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local_irq_disable();
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panic("bad mode");
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}
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void __pte_error(const char *file, int line, unsigned long val)
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{
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printk("%s:%d: bad pte %016lx.\n", file, line, val);
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}
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void __pmd_error(const char *file, int line, unsigned long val)
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{
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printk("%s:%d: bad pmd %016lx.\n", file, line, val);
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}
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void __pgd_error(const char *file, int line, unsigned long val)
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{
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printk("%s:%d: bad pgd %016lx.\n", file, line, val);
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}
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void __init trap_init(void)
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{
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return;
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}
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