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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65D75C433F5 for ; Wed, 13 Oct 2021 11:27:06 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 2C44860555 for ; Wed, 13 Oct 2021 11:27:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2C44860555 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=oDZZbtQvm7drbr6uVZuy6kRfIfs3yb1KlqsGuTWnSmA=; b=PP94JPhH2naYDV Sc/eVqlImzjCGb8FdNyjKus3GJ6zyJvYSmkbT5QjvFIEUZ5DirzzPk3YLbU+yDPz6VRwh3DFHt3Em 2sp6toDg9SdjR6MmLKJ2IagSMJ505jgdgmm48Kqke3zDIH4wmPIjzpM2/Fe1O3EZaTj3tiP/gQA1Z uh4Zb0bzIrXXDPBh86nsCTD5qn2cUNJcIKcL4XiYLaRX3jVHxvC7iPQQe2hFsrTNV9HGpHZV89eFb c8B1fo7Uow74ryZlza5oJZPmcAKRKbAsu1Z6iDC0lF1uo16yAMElJkAtpH70lxcR3Zy7rsStR5ufg R6i59VYx/q3XU4eoIytg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1macNb-00GINs-Kx; Wed, 13 Oct 2021 11:25:04 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mab5A-00Fsfo-HO for linux-arm-kernel@lists.infradead.org; Wed, 13 Oct 2021 10:01:58 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 073791063; Wed, 13 Oct 2021 03:01:52 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.73.189]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3C3DB3F70D; Wed, 13 Oct 2021 03:01:49 -0700 (PDT) Date: Wed, 13 Oct 2021 11:01:39 +0100 From: Mark Rutland To: Masami Hiramatsu Cc: Steven Rostedt , "Naveen N . Rao" , Ananth N Mavinakayanahalli , Ingo Molnar , linux-kernel@vger.kernel.org, Sven Schnelle , Catalin Marinas , Will Deacon , Russell King , Nathan Chancellor , Nick Desaulniers , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 3/8] arm64: kprobes: Record frame pointer with kretprobe instance Message-ID: <20211013100126.GA3187@C02TD0UTHF1T.local> References: <163369609308.636038.15295764725220907794.stgit@devnote2> <163369611948.636038.11552166777773804729.stgit@devnote2> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <163369611948.636038.11552166777773804729.stgit@devnote2> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211013_030156_693730_233746B9 X-CRM114-Status: GOOD ( 18.41 ) 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Oct 08, 2021 at 09:28:39PM +0900, Masami Hiramatsu wrote: > Record the frame pointer instead of stack address with kretprobe > instance as the identifier on the instance list. > Since arm64 always enable CONFIG_FRAME_POINTER, we can use the > actual frame pointer (x29). Just to check, why do we need to use the FP rather than SP? It wasn't clear to me if that's necessary later in the series, or if I'm missing something here. FWIW, I plan to rework arm64's ftrace bits to use FP for HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, so I'm happy to do likewise here. > Signed-off-by: Masami Hiramatsu Regardless of the above: Acked-by: Mark Rutland Mark. > --- > arch/arm64/kernel/probes/kprobes.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c > index e7ad6da980e8..d9dfa82c1f18 100644 > --- a/arch/arm64/kernel/probes/kprobes.c > +++ b/arch/arm64/kernel/probes/kprobes.c > @@ -401,14 +401,14 @@ int __init arch_populate_kprobe_blacklist(void) > > void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs) > { > - return (void *)kretprobe_trampoline_handler(regs, (void *)kernel_stack_pointer(regs)); > + return (void *)kretprobe_trampoline_handler(regs, (void *)regs->regs[29]); > } > > void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, > struct pt_regs *regs) > { > ri->ret_addr = (kprobe_opcode_t *)regs->regs[30]; > - ri->fp = (void *)kernel_stack_pointer(regs); > + ri->fp = (void *)regs->regs[29]; > > /* replace return addr (x30) with trampoline */ > regs->regs[30] = (long)&__kretprobe_trampoline; > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel