Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751625AbbBKETb (ORCPT ); Tue, 10 Feb 2015 23:19:31 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:7146 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751235AbbBKETa (ORCPT ); Tue, 10 Feb 2015 23:19:30 -0500 Message-ID: <54DAD82F.8010605@huawei.com> Date: Wed, 11 Feb 2015 12:18:55 +0800 From: Wang Nan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Andrew Morton CC: , , , , , Subject: Re: [PATCH][RESEND] kprobes: x86: mark 2 bytes NOP as boostable. References: <54D94415.8070206@hitachi.com> <1423532045-41049-1-git-send-email-wangnan0@huawei.com> In-Reply-To: <1423532045-41049-1-git-send-email-wangnan0@huawei.com> Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.111.69.129] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1783 Lines: 46 Hi Andrew, Could you please queue this patch onto your -mm tree? Masami has given an Acked-by already. Thank you! On 2015/2/10 9:34, Wang Nan wrote: > Currently, x86 kprobes is unable to boost 2 bytes nop like: > > nopl 0x0(%rax,%rax,1) > > which is 0x0f 0x1f 0x44 0x00 0x00. > > Such nops have exactly 5 bytes to hold a relative jmp instruction. > Boosting them should be obviously safe. > > This patch enable boosting such nops by simply updating > twobyte_is_boostable[] array. > > Signed-off-by: Wang Nan > Acked-by: Masami Hiramatsu > --- > arch/x86/kernel/kprobes/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > index 98f654d..6a1146e 100644 > --- a/arch/x86/kernel/kprobes/core.c > +++ b/arch/x86/kernel/kprobes/core.c > @@ -84,7 +84,7 @@ static volatile u32 twobyte_is_boostable[256 / 32] = { > /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ > /* ---------------------------------------------- */ > W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */ > - W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */ > + W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1) , /* 10 */ > W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */ > W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */ > W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/