// SPDX-License-Identifier: GPL-2.0
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#include <linux/bug.h>
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#include <linux/io.h>
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#include <linux/types.h>
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#include <linux/kdebug.h>
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/sched/debug.h>
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#include <linux/sched/task_stack.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <linux/kernel.h>
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#include <linux/kexec.h>
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#include <linux/sched/signal.h>
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#include <linux/extable.h>
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#include <linux/module.h> /* print_modules */
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#include <asm/unwinder.h>
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#include <asm/traps.h>
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static DEFINE_SPINLOCK(die_lock);
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void die(const char *str, struct pt_regs *regs, long err)
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{
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static int die_counter;
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oops_enter();
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spin_lock_irq(&die_lock);
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console_verbose();
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bust_spinlocks(1);
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printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++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 = %p)\n", current->comm,
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task_pid_nr(current), task_stack_page(current) + 1);
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if (!user_mode(regs) || in_interrupt())
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dump_mem("Stack: ", KERN_DEFAULT, regs->regs[15],
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THREAD_SIZE + (unsigned long)task_stack_page(current));
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notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
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bust_spinlocks(0);
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add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
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spin_unlock_irq(&die_lock);
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oops_exit();
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if (kexec_should_crash(current))
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crash_kexec(regs);
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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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make_task_dead(SIGSEGV);
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}
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void die_if_kernel(const char *str, struct pt_regs *regs, long err)
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{
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if (!user_mode(regs))
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die(str, regs, err);
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}
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/*
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* try and fix up kernelspace address errors
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* - userspace errors just cause EFAULT to be returned, resulting in SEGV
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* - kernel/userspace interfaces cause a jump to an appropriate handler
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* - other kernel errors are bad
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*/
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void die_if_no_fixup(const char *str, struct pt_regs *regs, long err)
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{
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if (!user_mode(regs)) {
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const struct exception_table_entry *fixup;
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fixup = search_exception_tables(regs->pc);
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if (fixup) {
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regs->pc = fixup->fixup;
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return;
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}
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die(str, regs, err);
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}
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}
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#ifdef CONFIG_GENERIC_BUG
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static void handle_BUG(struct pt_regs *regs)
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{
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const struct bug_entry *bug;
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unsigned long bugaddr = regs->pc;
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enum bug_trap_type tt;
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if (!is_valid_bugaddr(bugaddr))
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goto invalid;
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bug = find_bug(bugaddr);
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/* Switch unwinders when unwind_stack() is called */
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if (bug->flags & BUGFLAG_UNWINDER)
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unwinder_faulted = 1;
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tt = report_bug(bugaddr, regs);
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if (tt == BUG_TRAP_TYPE_WARN) {
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regs->pc += instruction_size(bugaddr);
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return;
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}
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invalid:
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die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
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}
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int is_valid_bugaddr(unsigned long addr)
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{
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insn_size_t opcode;
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if (addr < PAGE_OFFSET)
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return 0;
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if (get_kernel_nofault(opcode, (insn_size_t *)addr))
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return 0;
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if (opcode == TRAPA_BUG_OPCODE)
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return 1;
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return 0;
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}
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#endif
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/*
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* Generic trap handler.
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*/
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BUILD_TRAP_HANDLER(debug)
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{
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TRAP_HANDLER_DECL;
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/* Rewind */
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regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
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if (notify_die(DIE_TRAP, "debug trap", regs, 0, vec & 0xff,
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SIGTRAP) == NOTIFY_STOP)
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return;
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force_sig(SIGTRAP);
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}
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/*
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* Special handler for BUG() traps.
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*/
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BUILD_TRAP_HANDLER(bug)
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{
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TRAP_HANDLER_DECL;
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/* Rewind */
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regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
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if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
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SIGTRAP) == NOTIFY_STOP)
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return;
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#ifdef CONFIG_GENERIC_BUG
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if (__kernel_text_address(instruction_pointer(regs))) {
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insn_size_t insn = *(insn_size_t *)instruction_pointer(regs);
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if (insn == TRAPA_BUG_OPCODE)
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handle_BUG(regs);
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return;
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}
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#endif
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force_sig(SIGTRAP);
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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extern void arch_ftrace_nmi_enter(void);
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extern void arch_ftrace_nmi_exit(void);
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#else
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static inline void arch_ftrace_nmi_enter(void) { }
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static inline void arch_ftrace_nmi_exit(void) { }
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#endif
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BUILD_TRAP_HANDLER(nmi)
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{
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unsigned int cpu = smp_processor_id();
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TRAP_HANDLER_DECL;
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arch_ftrace_nmi_enter();
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nmi_enter();
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nmi_count(cpu)++;
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switch (notify_die(DIE_NMI, "NMI", regs, 0, vec & 0xff, SIGINT)) {
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case NOTIFY_OK:
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case NOTIFY_STOP:
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break;
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case NOTIFY_BAD:
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die("Fatal Non-Maskable Interrupt", regs, SIGINT);
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default:
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printk(KERN_ALERT "Got NMI, but nobody cared. Ignoring...\n");
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break;
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}
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nmi_exit();
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arch_ftrace_nmi_exit();
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}
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