arch/arm64/kernel/traps.c - maze/linux - Git at Google

 /*
  * Based on arch/arm/kernel/traps.c
  *
  * Copyright (C) 1995-2009 Russell King
  * Copyright (C) 2012 ARM Ltd.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include <linux/signal.h>
 #include <linux/personality.h>
 #include <linux/kallsyms.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.h>
 #include <linux/syscalls.h>

 #include <asm/atomic.h>
 #include <asm/debug-monitors.h>
 #include <asm/traps.h>
 #include <asm/stacktrace.h>
 #include <asm/exception.h>
 #include <asm/system_misc.h>

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

 int show_unhandled_signals = 1;

 /*
  * Dump out the contents of some memory nicely...
  */
 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
 		     unsigned long top)
 {
 	unsigned long first;
 	mm_segment_t fs;
 	int i;

 	/*
 	 * We need to switch to kernel mode so that we can use __get_user
 	 * to safely read from kernel space.  Note that we now dump the
 	 * code first, just in case the backtrace kills us.
 	 */
 	fs = get_fs();
 	set_fs(KERNEL_DS);

 	printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);

 	for (first = bottom & ~31; first < top; first += 32) {
 		unsigned long p;
 		char str[sizeof(" 12345678") * 8 + 1];

 		memset(str, ' ', sizeof(str));
 		str[sizeof(str) - 1] = '\0';

 		for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
 			if (p >= bottom && p < top) {
 				unsigned int val;
 				if (__get_user(val, (unsigned int *)p) == 0)
 					sprintf(str + i * 9, " %08x", val);
 				else
 					sprintf(str + i * 9, " ????????");
 			}
 		}
 		printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
 	}

 	set_fs(fs);
 }

 static void dump_backtrace_entry(unsigned long where, unsigned long stack)
 {
 	print_ip_sym(where);
 	if (in_exception_text(where))
 		dump_mem("", "Exception stack", stack,
 			 stack + sizeof(struct pt_regs));
 }

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

 	/*
 	 * We need to switch to kernel mode so that we can use __get_user
 	 * to safely read from kernel space.  Note that we now dump the
 	 * code first, just in case the backtrace kills us.
 	 */
 	fs = get_fs();
 	set_fs(KERNEL_DS);

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

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

 		if (!bad)
 			p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
 		else {
 			p += sprintf(p, "bad PC value");
 			break;
 		}
 	}
 	printk("%sCode: %s\n", lvl, str);

 	set_fs(fs);
 }

 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 {
 	struct stackframe frame;
 	const register unsigned long current_sp asm ("sp");

 	pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);

 	if (!tsk)
 		tsk = current;

 	if (regs) {
 		frame.fp = regs->regs[29];
 		frame.sp = regs->sp;
 		frame.pc = regs->pc;
 	} else if (tsk == current) {
 		frame.fp = (unsigned long)__builtin_frame_address(0);
 		frame.sp = current_sp;
 		frame.pc = (unsigned long)dump_backtrace;
 	} else {
 		/*
 		 * task blocked in __switch_to
 		 */
 		frame.fp = thread_saved_fp(tsk);
 		frame.sp = thread_saved_sp(tsk);
 		frame.pc = thread_saved_pc(tsk);
 	}

 	printk("Call trace:\n");
 	while (1) {
 		unsigned long where = frame.pc;
 		int ret;

 		ret = unwind_frame(&frame);
 		if (ret < 0)
 			break;
 		dump_backtrace_entry(where, frame.sp);
 	}
 }

 void show_stack(struct task_struct *tsk, unsigned long *sp)
 {
 	dump_backtrace(NULL, tsk);
 	barrier();
 }

 #ifdef CONFIG_PREEMPT
 #define S_PREEMPT " PREEMPT"
 #else
 #define S_PREEMPT ""
 #endif
 #ifdef CONFIG_SMP
 #define S_SMP " SMP"
 #else
 #define S_SMP ""
 #endif

 static int __die(const char *str, int err, struct thread_info *thread,
 		 struct pt_regs *regs)
 {
 	struct task_struct *tsk = thread->task;
 	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);
 	pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
 		 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);

 	if (!user_mode(regs) || in_interrupt()) {
 		dump_mem(KERN_EMERG, "Stack: ", regs->sp,
 			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
 		dump_backtrace(regs, tsk);
 		dump_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)
 {
 	struct thread_info *thread = current_thread_info();
 	int ret;

 	oops_enter();

 	raw_spin_lock_irq(&die_lock);
 	console_verbose();
 	bust_spinlocks(1);
 	ret = __die(str, err, thread, regs);

 	if (regs && kexec_should_crash(thread->task))
 		crash_kexec(regs);

 	bust_spinlocks(0);
 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	raw_spin_unlock_irq(&die_lock);
 	oops_exit();

 	if (in_interrupt())
 		panic("Fatal exception in interrupt");
 	if (panic_on_oops)
 		panic("Fatal exception");
 	if (ret != NOTIFY_STOP)
 		do_exit(SIGSEGV);
 }

 void arm64_notify_die(const char *str, struct pt_regs *regs,
 		      struct siginfo *info, int err)
 {
 	if (user_mode(regs))
 		force_sig_info(info->si_signo, info, current);
 	else
 		die(str, regs, err);
 }

 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 {
 	siginfo_t info;
 	void __user *pc = (void __user *)instruction_pointer(regs);

 	/* check for AArch32 breakpoint instructions */
 	if (!aarch32_break_handler(regs))
 		return;

 	if (show_unhandled_signals && unhandled_signal(current, SIGILL) &&
 	    printk_ratelimit()) {
 		pr_info("%s[%d]: undefined instruction: pc=%p\n",
 			current->comm, task_pid_nr(current), pc);
 		dump_instr(KERN_INFO, regs);
 	}

 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code  = ILL_ILLOPC;
 	info.si_addr  = pc;

 	arm64_notify_die("Oops - undefined instruction", regs, &info, 0);
 }

 long compat_arm_syscall(struct pt_regs *regs);

 asmlinkage long do_ni_syscall(struct pt_regs *regs)
 {
 #ifdef CONFIG_COMPAT
 	long ret;
 	if (is_compat_task()) {
 		ret = compat_arm_syscall(regs);
 		if (ret != -ENOSYS)
 			return ret;
 	}
 #endif

 	if (show_unhandled_signals && printk_ratelimit()) {
 		pr_info("%s[%d]: syscall %d\n", current->comm,
 			task_pid_nr(current), (int)regs->syscallno);
 		dump_instr("", regs);
 		if (user_mode(regs))
 			__show_regs(regs);
 	}

 	return sys_ni_syscall();
 }

 /*
  * bad_mode handles the impossible case in the exception vector.
  */
 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 {
 	siginfo_t info;
 	void __user *pc = (void __user *)instruction_pointer(regs);
 	console_verbose();

 	pr_crit("Bad mode in %s handler detected, code 0x%08x\n",
 		handler[reason], esr);
 	__show_regs(regs);

 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code  = ILL_ILLOPC;
 	info.si_addr  = pc;

 	arm64_notify_die("Oops - bad mode", regs, &info, 0);
 }

 void __pte_error(const char *file, int line, unsigned long val)
 {
 	printk("%s:%d: bad pte %016lx.\n", file, line, val);
 }

 void __pmd_error(const char *file, int line, unsigned long val)
 {
 	printk("%s:%d: bad pmd %016lx.\n", file, line, val);
 }

 void __pgd_error(const char *file, int line, unsigned long val)
 {
 	printk("%s:%d: bad pgd %016lx.\n", file, line, val);
 }

 void __init trap_init(void)
 {
 	return;
 }
	/*
	* Based on arch/arm/kernel/traps.c
	*
	* Copyright (C) 1995-2009 Russell King
	* Copyright (C) 2012 ARM Ltd.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include <linux/signal.h>
	#include <linux/personality.h>
	#include <linux/kallsyms.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.h>
	#include <linux/syscalls.h>

	#include <asm/atomic.h>
	#include <asm/debug-monitors.h>
	#include <asm/traps.h>
	#include <asm/stacktrace.h>
	#include <asm/exception.h>
	#include <asm/system_misc.h>

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

	int show_unhandled_signals = 1;

	/*
	* Dump out the contents of some memory nicely...
	*/
	static void dump_mem(const char lvl, const char str, unsigned long bottom,
	unsigned long top)
	{
	unsigned long first;
	mm_segment_t fs;
	int i;

	/*
	* We need to switch to kernel mode so that we can use __get_user
	* to safely read from kernel space. Note that we now dump the
	* code first, just in case the backtrace kills us.
	*/
	fs = get_fs();
	set_fs(KERNEL_DS);

	printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);

	for (first = bottom & ~31; first < top; first += 32) {
	unsigned long p;
	char str[sizeof(" 12345678") * 8 + 1];

	memset(str, ' ', sizeof(str));
	str[sizeof(str) - 1] = '\0';

	for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
	if (p >= bottom && p < top) {
	unsigned int val;
	if (__get_user(val, (unsigned int *)p) == 0)
	sprintf(str + i * 9, " %08x", val);
	else
	sprintf(str + i * 9, " ????????");
	}
	}
	printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
	}

	set_fs(fs);
	}

	static void dump_backtrace_entry(unsigned long where, unsigned long stack)
	{
	print_ip_sym(where);
	if (in_exception_text(where))
	dump_mem("", "Exception stack", stack,
	stack + sizeof(struct pt_regs));
	}

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

	/*
	* We need to switch to kernel mode so that we can use __get_user
	* to safely read from kernel space. Note that we now dump the
	* code first, just in case the backtrace kills us.
	*/
	fs = get_fs();
	set_fs(KERNEL_DS);

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

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

	if (!bad)
	p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
	else {
	p += sprintf(p, "bad PC value");
	break;
	}
	}
	printk("%sCode: %s\n", lvl, str);

	set_fs(fs);
	}

	static void dump_backtrace(struct pt_regs regs, struct task_struct tsk)
	{
	struct stackframe frame;
	const register unsigned long current_sp asm ("sp");

	pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);

	if (!tsk)
	tsk = current;

	if (regs) {
	frame.fp = regs->regs[29];
	frame.sp = regs->sp;
	frame.pc = regs->pc;
	} else if (tsk == current) {
	frame.fp = (unsigned long)__builtin_frame_address(0);
	frame.sp = current_sp;
	frame.pc = (unsigned long)dump_backtrace;
	} else {
	/*
	* task blocked in __switch_to
	*/
	frame.fp = thread_saved_fp(tsk);
	frame.sp = thread_saved_sp(tsk);
	frame.pc = thread_saved_pc(tsk);
	}

	printk("Call trace:\n");
	while (1) {
	unsigned long where = frame.pc;
	int ret;

	ret = unwind_frame(&frame);
	if (ret < 0)
	break;
	dump_backtrace_entry(where, frame.sp);
	}
	}

	void show_stack(struct task_struct tsk, unsigned long sp)
	{
	dump_backtrace(NULL, tsk);
	barrier();
	}

	#ifdef CONFIG_PREEMPT
	#define S_PREEMPT " PREEMPT"
	#else
	#define S_PREEMPT ""
	#endif
	#ifdef CONFIG_SMP
	#define S_SMP " SMP"
	#else
	#define S_SMP ""
	#endif

	static int __die(const char str, int err, struct thread_info thread,
	struct pt_regs *regs)
	{
	struct task_struct *tsk = thread->task;
	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);
	pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
	TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);

	if (!user_mode(regs) \|\| in_interrupt()) {
	dump_mem(KERN_EMERG, "Stack: ", regs->sp,
	THREAD_SIZE + (unsigned long)task_stack_page(tsk));
	dump_backtrace(regs, tsk);
	dump_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)
	{
	struct thread_info *thread = current_thread_info();
	int ret;

	oops_enter();

	raw_spin_lock_irq(&die_lock);
	console_verbose();
	bust_spinlocks(1);
	ret = __die(str, err, thread, regs);

	if (regs && kexec_should_crash(thread->task))
	crash_kexec(regs);

	bust_spinlocks(0);
	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
	raw_spin_unlock_irq(&die_lock);
	oops_exit();

	if (in_interrupt())
	panic("Fatal exception in interrupt");
	if (panic_on_oops)
	panic("Fatal exception");
	if (ret != NOTIFY_STOP)
	do_exit(SIGSEGV);
	}

	void arm64_notify_die(const char str, struct pt_regs regs,
	struct siginfo *info, int err)
	{
	if (user_mode(regs))
	force_sig_info(info->si_signo, info, current);
	else
	die(str, regs, err);
	}

	asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
	{
	siginfo_t info;
	void __user pc = (void __user )instruction_pointer(regs);

	/* check for AArch32 breakpoint instructions */
	if (!aarch32_break_handler(regs))
	return;

	if (show_unhandled_signals && unhandled_signal(current, SIGILL) &&
	printk_ratelimit()) {
	pr_info("%s[%d]: undefined instruction: pc=%p\n",
	current->comm, task_pid_nr(current), pc);
	dump_instr(KERN_INFO, regs);
	}

	info.si_signo = SIGILL;
	info.si_errno = 0;
	info.si_code = ILL_ILLOPC;
	info.si_addr = pc;

	arm64_notify_die("Oops - undefined instruction", regs, &info, 0);
	}

	long compat_arm_syscall(struct pt_regs *regs);

	asmlinkage long do_ni_syscall(struct pt_regs *regs)
	{
	#ifdef CONFIG_COMPAT
	long ret;
	if (is_compat_task()) {
	ret = compat_arm_syscall(regs);
	if (ret != -ENOSYS)
	return ret;
	}
	#endif

	if (show_unhandled_signals && printk_ratelimit()) {
	pr_info("%s[%d]: syscall %d\n", current->comm,
	task_pid_nr(current), (int)regs->syscallno);
	dump_instr("", regs);
	if (user_mode(regs))
	__show_regs(regs);
	}

	return sys_ni_syscall();
	}

	/*
	* bad_mode handles the impossible case in the exception vector.
	*/
	asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
	{
	siginfo_t info;
	void __user pc = (void __user )instruction_pointer(regs);
	console_verbose();

	pr_crit("Bad mode in %s handler detected, code 0x%08x\n",
	handler[reason], esr);
	__show_regs(regs);

	info.si_signo = SIGILL;
	info.si_errno = 0;
	info.si_code = ILL_ILLOPC;
	info.si_addr = pc;

	arm64_notify_die("Oops - bad mode", regs, &info, 0);
	}

	void __pte_error(const char *file, int line, unsigned long val)
	{
	printk("%s:%d: bad pte %016lx.\n", file, line, val);
	}

	void __pmd_error(const char *file, int line, unsigned long val)
	{
	printk("%s:%d: bad pmd %016lx.\n", file, line, val);
	}

	void __pgd_error(const char *file, int line, unsigned long val)
	{
	printk("%s:%d: bad pgd %016lx.\n", file, line, val);
	}

	void __init trap_init(void)
	{
	return;
	}