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Date: Tue, 21 Oct 2014 10:51:31 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Organization: Hitachi, Ltd., Japan
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To: Steven Rostedt <rostedt@goodmis.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>,
        Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Ingo Molnar <mingo@redhat.com>, Vojtech Pavlik <vojtech@suse.cz>,
        Jiri Kosina <jkosina@suse.cz>, Jiri Slaby <jslaby@suse.cz>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] kprobes: introduce ARCH_HANDLES_KPROBES_ON_FTRACE
References: <1413387978-984-1-git-send-email-heiko.carstens@de.ibm.com> <1413387978-984-2-git-send-email-heiko.carstens@de.ibm.com> <54446B92.1040507@hitachi.com> <20141020145321.0af7a4dd@gandalf.local.home>
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(2014/10/21 3:53), Steven Rostedt wrote:
> On Mon, 20 Oct 2014 10:55:30 +0900
> Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
> 
> 
>> Hmm, this looks a bit not straight. Maybe we'd better introduce a local
>> check_ftrace_location() function which always returns 0 if
>> CONFIG_ARCH_HANDLES_KPROBES_ON_FTRACE(with a comment! :)) as below.
>>
>> int check_ftrace_location(kp)
>> {
>> 	unsigned long ftrace_address;
>>
>> 	/* If an architecture handles kprobes on ftrace, we don't check it */
>> 	if (IS_ENABLED(CONFIG_ARCH_HANDLES_KPROBES_ON_FTRACE))
>> 		return 0;
>>
>> 	...
>> }
> 
> We can also just make that function weak, and let the archs override
> the default behavior?

Ah, that will be simpler and we don't need new Kconfig.

Thank you!

-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com