From mboxrd@z Thu Jan  1 00:00:00 1970
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Subject: Re: Re: [PATCH -tip RFC v2 01/22] kprobes: Prohibit probing on
	.entry.text code
Date: Sun, 17 Nov 2013 16:21:27 +0900
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To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linux-Arch <linux-arch@vger.kernel.org>, Ananth N Mavinakayanahalli <ananth@in.ibm.com>, "David S. Miller" <davem@davemloft.net>, Peter Zijlstra <peterz@infradead.org>, Frederic Weisbecker <fweisbec@gmail.com>, the arch/x86 maintainers <x86@kernel.org>, lkml <linux-kernel@vger.kernel.org>, Steven Rostedt <rostedt@goodmis.org>, virtualization@lists.linux-foundation.org, Ingo Molnar <mingo@redhat.com>, Al Viro <viro@zeniv.linux.org.uk>, "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>, Seiji Aguchi <seiji.aguchi@hds.com>, Ingo Molnar <mingo@kernel.org>
List-Id: virtualization@lists.linuxfoundation.org

(2013/11/16 2:46), Geert Uytterhoeven wrote:
> On Fri, Nov 15, 2013 at 5:43 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
>> On Fri, 15 Nov 2013 04:53:18 +0000
>> Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
>>
>>> .entry.text is a code area which is used for interrupt/syscall
>>> entries, and there are many sensitive codes.
>>> Thus, it is better to prohibit probing on all of such codes
>>> instead of a part of that.
>>> Since some symbols are already registered on kprobe blacklist,
>>> this also removes them from the blacklist.
>>
>> This change only works with x86. On other archs, I get this:
>>
>> kernel/built-in.o: In function `register_kprobe':
>> (.kprobes.text+0x9f4): undefined reference to `__entry_text_start'
>> kernel/built-in.o: In function `register_kprobe':
>> (.kprobes.text+0x9f8): undefined reference to `__entry_text_end'
>> make[1]: *** [vmlinux] Error 1
>> make: *** [sub-make] Error 2
> 
> X86 is the sole architecture that has ENTRY_TEXT in its
> arch/*/kernel/vmlinux.lds.S.

Ah, thanks! I'll fix that.
BTW, should I add CONFIG_HAVE_ENTRY_TEXT for x86 and use it
or just use CONFIG_X86 to detect it?

Thank you,

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