Merge tag 'arm64-stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64

Pull arm64 fixes from Catalin Marinas:
 - Module compilation issues (symbol not exported).
 - Plug a hole where user space can bring the kernel down.

* tag 'arm64-stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64:
  arm64: don't kill the kernel on a bad esr from el0
  arm64: treat unhandled compat el0 traps as undef
  arm64: Do not report user faults for handled signals
  arm64: kernel: compiling issue, need 'EXPORT_SYMBOL(clear_page)'

arch/arm64/kernel/arm64ksyms.c

@@ -34,6 +34,7 @@ EXPORT_SYMBOL(__strnlen_user);
 EXPORT_SYMBOL(__strncpy_from_user);
 
 EXPORT_SYMBOL(copy_page);
+EXPORT_SYMBOL(clear_page);
 
 EXPORT_SYMBOL(__copy_from_user);
 EXPORT_SYMBOL(__copy_to_user);

arch/arm64/kernel/entry.S

@@ -390,6 +390,16 @@ el0_sync_compat:
 	b.eq	el0_fpsimd_exc
 	cmp	x24, #ESR_EL1_EC_UNKNOWN	// unknown exception in EL0
 	b.eq	el0_undef
+	cmp	x24, #ESR_EL1_EC_CP15_32	// CP15 MRC/MCR trap
+	b.eq	el0_undef
+	cmp	x24, #ESR_EL1_EC_CP15_64	// CP15 MRRC/MCRR trap
+	b.eq	el0_undef
+	cmp	x24, #ESR_EL1_EC_CP14_MR	// CP14 MRC/MCR trap
+	b.eq	el0_undef
+	cmp	x24, #ESR_EL1_EC_CP14_LS	// CP14 LDC/STC trap
+	b.eq	el0_undef
+	cmp	x24, #ESR_EL1_EC_CP14_64	// CP14 MRRC/MCRR trap
+	b.eq	el0_undef
 	cmp	x24, #ESR_EL1_EC_BREAKPT_EL0	// debug exception in EL0
 	b.ge	el0_dbg
 	b	el0_inv

arch/arm64/kernel/traps.c

@@ -267,7 +267,8 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 		return;
 #endif
 
-	if (show_unhandled_signals) {
+	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);
@@ -294,7 +295,7 @@ asmlinkage long do_ni_syscall(struct pt_regs *regs)
 	}
 #endif
 
-	if (show_unhandled_signals) {
+	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);
@@ -310,14 +311,20 @@ asmlinkage long do_ni_syscall(struct pt_regs *regs)
  */
 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;
 
-	die("Oops - bad mode", regs, 0);
-	local_irq_disable();
-	panic("bad mode");
+	arm64_notify_die("Oops - bad mode", regs, &info, 0);
 }
 
 void __pte_error(const char *file, int line, unsigned long val)

arch/arm64/mm/fault.c

@@ -113,7 +113,8 @@ static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
 {
 	struct siginfo si;
 
-	if (show_unhandled_signals) {
+	if (show_unhandled_signals && unhandled_signal(tsk, sig) &&
+	    printk_ratelimit()) {
 		pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x\n",
 			tsk->comm, task_pid_nr(tsk), fault_name(esr), sig,
 			addr, esr);