path: root/arch/arm64/kernel/traps.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Based on arch/arm/kernel/traps.c
 *
 * Copyright (C) 1995-2009 Russell King
 * Copyright (C) 2012 ARM Ltd.
 */

#include <linux/bug.h>
#include <linux/context_tracking.h>
#include <linux/signal.h>
#include <linux/personality.h>
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/kexec.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/sched/signal.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
#include <linux/sizes.h>
#include <linux/syscalls.h>
#include <linux/mm_types.h>
#include <linux/kasan.h>

#include <asm/atomic.h>
#include <asm/bug.h>
#include <asm/cpufeature.h>
#include <asm/daifflags.h>
#include <asm/debug-monitors.h>
#include <asm/esr.h>
#include <asm/exception.h>
#include <asm/extable.h>
#include <asm/insn.h>
#include <asm/kprobes.h>
#include <asm/traps.h>
#include <asm/smp.h>
#include <asm/stack_pointer.h>
#include <asm/stacktrace.h>
#include <asm/exception.h>
#include <asm/system_misc.h>
#include <asm/sysreg.h>

static const char *handler[]= {
	"Synchronous Abort",
	"IRQ",
	"FIQ",
	"Error"
};

int show_unhandled_signals = 0;

static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
{
	unsigned long addr = instruction_pointer(regs);
	char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
	int i;

	if (user_mode(regs))
		return;

	for (i = -4; i < 1; i++) {
		unsigned int val, bad;

		bad = aarch64_insn_read(&((u32 *)addr)[i], &val);

		if (!bad)
			p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
		else {
			p += sprintf(p, "bad PC value");
			break;
		}
	}

	printk("%sCode: %s\n", lvl, str);
}

#ifdef CONFIG_PREEMPT
#define S_PREEMPT " PREEMPT"
#elif defined(CONFIG_PREEMPT_RT)
#define S_PREEMPT " PREEMPT_RT"
#else
#define S_PREEMPT ""
#endif

#define S_SMP " SMP"

static int __die(const char *str, int err, struct pt_regs *regs)
{
	static int die_counter;
	int ret;

	pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
		 str, err, ++die_counter);

	/* trap and error numbers are mostly meaningless on ARM */
	ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
	if (ret == NOTIFY_STOP)
		return ret;

	print_modules();
	show_regs(regs);

	dump_kernel_instr(KERN_EMERG, regs);

	return ret;
}

static DEFINE_RAW_SPINLOCK(die_lock);

/*
 * This function is protected against re-entrancy.
 */
void die(const char *str, struct pt_regs *regs, int err)
{
	int ret;
	unsigned long flags;

	raw_spin_lock_irqsave(&die_lock, flags);

	oops_enter();

	console_verbose();
	bust_spinlocks(1);
	ret = __die(str, err, regs);

	if (regs && kexec_should_crash(current))
		crash_kexec(regs);

	bust_spinlocks(0);
	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
	oops_exit();

	if (in_interrupt())
		panic("%s: Fatal exception in interrupt", str);
	if (panic_on_oops)
		panic("%s: Fatal exception", str);

	raw_spin_unlock_irqrestore(&die_lock, flags);

	if (ret != NOTIFY_STOP)
		do_exit(SIGSEGV);
}

static void arm64_show_signal(int signo, const char *str)
{
	static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
				      DEFAULT_RATELIMIT_BURST);
	struct task_struct *tsk = current;
	unsigned int esr = tsk->thread.fault_code;
	struct pt_regs *regs = task_pt_regs(tsk);

	/* Leave if the signal won't be shown */
	if (!show_unhandled_signals ||
	    !unhandled_signal(tsk, signo) ||
	    !__ratelimit(&rs))
		return;

	pr_info("%s[%d]: unhandled exception: ", tsk->comm, task_pid_nr(tsk));
	if (esr)
		pr_cont("%s, ESR 0x%08x, ", esr_get_class_string(esr), esr);

	pr_cont("%s", str);
	print_vma_addr(KERN_CONT " in ", regs->pc);
	pr_cont("\n");
	__show_regs(regs);
}

void arm64_force_sig_fault(int signo, int code, void __user *addr,
			   const char *str)
{
	arm64_show_signal(signo, str);
	if (signo == SIGKILL)
		force_sig(SIGKILL);
	else
		force_sig_fault(signo, code, addr);
}

void arm64_force_sig_mceerr(int code, void __user *addr, short lsb,
			    const char *str)
{
	arm64_show_signal(SIGBUS, str);
	force_sig_mceerr(code, addr, lsb);
}

void arm64_force_sig_ptrace_errno_trap(int errno, void __user *addr,
				       const char *str)
{
	arm64_show_signal(SIGTRAP, str);
	force_sig_ptrace_errno_trap(errno, addr);
}

void arm64_notify_die(const char *str, struct pt_regs *regs,
		      int signo, int sicode, void __user *addr,
		      int err)
{
	if (user_mode(regs)) {
		WARN_ON(