From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B45C0C433F5 for ; Fri, 26 Nov 2021 10:32:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:CC:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=zHlAtVObhWjK8RNPhp9ezqoiu2Mlb3vYEfCn5fu5kHA=; b=0e3RMBUtYhnonJhuI+S+2++zZg n9YbLFVdNtDHz8Y7KAf24HGiKyttSekLssvTcCyPwrQS9GLu1KK/QZ/X6nJMiqBooUELnI1OqtEUq E7U+QMNDPIVY7wsfBj0zrj6aUgZz9IyGh7fEZd9FC/ldOsR3/tuSn9sIpofgUjhZAhvCQHXlo8GM9 fvzCCahnRXns006LZNH8UYhWW49OhfZMs8BH0u7GHSW+KaoJy4CEpqkQZla9B5OQeIedu3Bl1Vrlr GPLaXP1NWx1GWYvxRx1fTyHr7N9Bc3RH0l4ubBRQyFa3zpWFnxJ68Jq+xHg0nsAa3cAr5l65+L7Gm PVgL8osA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mqYVm-00A1JQ-N8; Fri, 26 Nov 2021 10:31:22 +0000 Received: from szxga03-in.huawei.com ([45.249.212.189]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mqYVh-00A1Hq-Fi for linux-arm-kernel@lists.infradead.org; Fri, 26 Nov 2021 10:31:20 +0000 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4J0rZf59Kkz8vfM; Fri, 26 Nov 2021 18:29:14 +0800 (CST) Received: from kwepemm600003.china.huawei.com (7.193.23.202) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Fri, 26 Nov 2021 18:31:07 +0800 Received: from [10.67.102.185] (10.67.102.185) by kwepemm600003.china.huawei.com (7.193.23.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Fri, 26 Nov 2021 18:31:06 +0800 Subject: Re: [PATCH v4 2/2] arm64: kprobe: Enable OPTPROBE for arm64 To: Mark Rutland , CC: , , , , , , , , , , , , References: <20210818073336.59678-1-liuqi115@huawei.com> <20210818073336.59678-3-liuqi115@huawei.com> <20210824105001.GA96738@C02TD0UTHF1T.local> From: "liuqi (BA)" Message-ID: Date: Fri, 26 Nov 2021 18:31:06 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20210824105001.GA96738@C02TD0UTHF1T.local> Content-Language: en-GB X-Originating-IP: [10.67.102.185] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm600003.china.huawei.com (7.193.23.202) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211126_023117_922147_4998EA36 X-CRM114-Status: GOOD ( 16.43 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2021/8/24 18:50, Mark Rutland wrote: >> diff --git a/arch/arm64/kernel/probes/optprobe_trampoline.S b/arch/arm64/kernel/probes/optprobe_trampoline.S >> new file mode 100644 >> index 000000000000..24d713d400cd >> --- /dev/null >> +++ b/arch/arm64/kernel/probes/optprobe_trampoline.S >> @@ -0,0 +1,37 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* >> + * trampoline entry and return code for optprobes. >> + */ >> + >> +#include >> +#include >> +#include >> + >> + .global optprobe_template_entry >> +optprobe_template_entry: > Please use SYM_*(); see arch/arm64/kernel/entry-ftrace.S for examples of > how to use that for trampolines. > > This should be: > > SYM_CODE_START(optprobe_template) > Hi all, I meet a problem when I use SYM_CODE_START(optprobe_template) to replace optprobe_template_entry. If SYM_CODE_START is used, all optprobe will share one trampoline space. Under this circumstances, if user register two optprobes, trampoline will be overwritten by the newer one, and this will cause kernel panic when the old optprobe is trigger. Using optprobe_template_entry will not have this problem, as each optprobe has its own trampoline space (alloced in get_opinsn_slot()). So how to reuse SYM_CODE_START in this situation, does anyone has a good idea? Thanks, Qi > ... and note the matching end below. > >> + sub sp, sp, #PT_REGS_SIZE >> + save_all_base_regs >> + /* Get parameters to optimized_callback() */ >> + ldr x0, 1f >> + mov x1, sp >> + /* Branch to optimized_callback() */ >> + .global optprobe_template_call >> +optprobe_template_call: > SYM_INNER_LABEL(optprobe_template_call, SYM_L_GLOBAL) > > ...and likewise for all the other labels. > >> + nop >> + restore_all_base_regs >> + ldr lr, [sp, #S_LR] >> + add sp, sp, #PT_REGS_SIZE >> + .global optprobe_template_restore_orig_insn >> +optprobe_template_restore_orig_insn: >> + nop >> + .global optprobe_template_restore_end >> +optprobe_template_restore_end: >> + nop >> + .global optprobe_template_end >> +optprobe_template_end: >> + .global optprobe_template_val >> +optprobe_template_val: >> + 1: .long 0 >> + .long 0 >> + .global optprobe_template_max_length >> +optprobe_template_max_length: > SYM_INNER_LABEL(optprobe_template_end, SYM_L_GLOBAL) > SYM_CODE_END(optprobe_template) > > Thanks, > Mark. > >> -- _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel