Hi Yu-cheng,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on asm-generic/master]
[also build test ERROR on v4.17 next-20180607]
[cannot apply to tip/x86/core mmotm/master]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Yu-cheng-Yu/Control-Flow-Enforcement-Part-2/20180608-111152
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git master
config: i386-randconfig-a0-201822 (attached as .config)
compiler: gcc-4.9 (Debian 4.9.4-2) 4.9.4
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   In file included from arch/x86/include/asm/thread_info.h:53:0,
                    from include/linux/thread_info.h:38,
                    from arch/x86/include/asm/preempt.h:7,
                    from include/linux/preempt.h:81,
                    from include/linux/rcupdate.h:40,
                    from include/linux/rculist.h:11,
                    from include/linux/pid.h:5,
                    from include/linux/sched.h:14,
                    from include/linux/context_tracking.h:5,
                    from arch/x86/kernel/traps.c:15:
   arch/x86/kernel/traps.c: In function 'do_control_protection':
>> arch/x86/kernel/traps.c:605:27: error: 'X86_FEATURE_SHSTK' undeclared (first use in this function)
     if (!cpu_feature_enabled(X86_FEATURE_SHSTK) &&
                              ^
   arch/x86/include/asm/cpufeature.h:127:24: note: in definition of macro 'cpu_feature_enabled'
     (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
                           ^
   arch/x86/kernel/traps.c:605:27: note: each undeclared identifier is reported only once for each function it appears in
     if (!cpu_feature_enabled(X86_FEATURE_SHSTK) &&
                              ^
   arch/x86/include/asm/cpufeature.h:127:24: note: in definition of macro 'cpu_feature_enabled'
     (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
                           ^
>> arch/x86/kernel/traps.c:606:27: error: 'X86_FEATURE_IBT' undeclared (first use in this function)
         !cpu_feature_enabled(X86_FEATURE_IBT)) {
                              ^
   arch/x86/include/asm/cpufeature.h:127:24: note: in definition of macro 'cpu_feature_enabled'
     (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
                           ^

vim +/X86_FEATURE_SHSTK +605 arch/x86/kernel/traps.c

   589	
   590	/*
   591	 * When a control protection exception occurs, send a signal
   592	 * to the responsible application.  Currently, control
   593	 * protection is only enabled for the user mode.  This
   594	 * exception should not come from the kernel mode.
   595	 */
   596	dotraplinkage void
   597	do_control_protection(struct pt_regs *regs, long error_code)
   598	{
   599		struct task_struct *tsk;
   600	
   601		RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
   602		cond_local_irq_enable(regs);
   603	
   604		tsk = current;
 > 605		if (!cpu_feature_enabled(X86_FEATURE_SHSTK) &&
 > 606		    !cpu_feature_enabled(X86_FEATURE_IBT)) {
   607			goto exit;
   608		}
   609	
   610		if (!user_mode(regs)) {
   611			tsk->thread.error_code = error_code;
   612			tsk->thread.trap_nr = X86_TRAP_CP;
   613			if (notify_die(DIE_TRAP, "control protection fault", regs,
   614				       error_code, X86_TRAP_CP, SIGSEGV) != NOTIFY_STOP)
   615				die("control protection fault", regs, error_code);
   616			return;
   617		}
   618	
   619		tsk->thread.error_code = error_code;
   620		tsk->thread.trap_nr = X86_TRAP_CP;
   621	
   622		if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
   623		    printk_ratelimit()) {
   624			unsigned int max_idx, err_idx;
   625	
   626			max_idx = ARRAY_SIZE(control_protection_err) - 1;
   627			err_idx = min((unsigned int)error_code - 1, max_idx);
   628			pr_info("%s[%d] control protection ip:%lx sp:%lx error:%lx(%s)",
   629				tsk->comm, task_pid_nr(tsk),
   630				regs->ip, regs->sp, error_code,
   631				control_protection_err[err_idx]);
   632			print_vma_addr(" in ", regs->ip);
   633			pr_cont("\n");
   634		}
   635	
   636	exit:
   637		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
   638	}
   639	NOKPROBE_SYMBOL(do_control_protection);
   640	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation