linux-kernel - RE: [PATCH v4] trace,x86: add x86 irq vector tracepoints

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 27 Sep 2012 22:33:36 +0000
From:	Seiji Aguchi <seiji.aguchi@....com>
To:	"H. Peter Anvin" <hpa@...or.com>
CC:	"Thomas Gleixner (tglx@...utronix.de)" <tglx@...utronix.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"rostedt@...dmis.org" <rostedt@...dmis.org>,
	"'mingo@...e.hu' (mingo@...e.hu)" <mingo@...e.hu>,
	"x86@...nel.org" <x86@...nel.org>,
	"dle-develop@...ts.sourceforge.net" 
	<dle-develop@...ts.sourceforge.net>,
	Satoru Moriya <satoru.moriya@....com>
Subject: RE: [PATCH v4] trace,x86: add x86 irq vector tracepoints

Hi,

> ... except the cost can be reduced to zero *AND* be made into a more general mechanism by simply hooking the IDT.

Thank you for giving me the comment.
In my understanding,  we can introduce a more general mechanism by sandwiching an existing handler between tracepoints.
The pseudo code is like this:

@@ -17,7 +18,7 @@ static void default_threshold_interrupt(void)
 
 void (*mce_threshold_vector)(void) = default_threshold_interrupt;
 
-asmlinkage void smp_threshold_interrupt(void)
+static void do_smp_threshold_interrupt(void)
 {
 	irq_enter();
 	exit_idle();
@@ -27,3 +28,10 @@ asmlinkage void smp_threshold_interrupt(void)
 	/* Ack only at the end to avoid potential reentry */
 	ack_APIC_irq();
 }
+
+asmlinkage void smp_threshold_interrupt(void) {
+	trace_arch_irq_vector_entry(THRESHOLD_APIC_VECTOR);
+	do_smp_threshold_interrupt();
+	trace_arch_irq_vector_exit(THRESHOLD_APIC_VECTOR);
+}

If I misunderstand something, please let me know.

Seiji