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 51959C433EF for ; Tue, 5 Oct 2021 10:43:44 +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 1B6EB61502 for ; Tue, 5 Oct 2021 10:43:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1B6EB61502 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=I8PwhC9CBvu1VcAQw536AgbKvhDWqZhQAQUI36bfbu0=; b=IUTluUg6eEfMbM cQ+5DOFDnkwdDktUy1wTXk+3dMo9JuNSJVvp5R7JP7j2ScDmxt2l/T58MtICfYbMrNhBjKL5Noi+c 3ccHW+F352ykGPzyVTpkt9Gh1atrxzo54G5Hm0MfYVsqfJau1Nk7W4esERLQ+BeUvocWs1vX6MHaE 2kLLrFQBQEOV0B29vxXn8zeBLmFfBIIBBUIP7zUsu4ZkWaUuSoTgE4ilz/L59fUA3X+40cuw51Ojf x02fbXIzJqL6D7UnTdgSo0ocAEerRLWcVEU4INYwwx4iAamixGgKmtaGEeBqX2ILIpBoSp0iPN56k 7ZxA7viwNOTFSM/lRaWQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mXhtP-00A1AX-Di; Tue, 05 Oct 2021 10:41:51 +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 1mXhtG-00A18i-5q for linux-arm-kernel@lists.infradead.org; Tue, 05 Oct 2021 10:41:46 +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 E00CD6D; Tue, 5 Oct 2021 03:41:39 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.23.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C56AF3F766; Tue, 5 Oct 2021 03:41:34 -0700 (PDT) Date: Tue, 5 Oct 2021 11:41:31 +0100 From: Mark Rutland To: Sumit Garg Cc: linux-arm-kernel@lists.infradead.org, rostedt@goodmis.org, mingo@redhat.com, catalin.marinas@arm.com, will@kernel.org, samitolvanen@google.com, ben.dai@unisoc.com, nathan@kernel.org, keescook@chromium.org, daniel.thompson@linaro.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: ftrace: use function_nocfi for _mcount as well Message-ID: <20211005104131.GB1664@C02TD0UTHF1T.local> References: <20211005103208.2763305-1-sumit.garg@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20211005103208.2763305-1-sumit.garg@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211005_034145_157584_9542AD6D X-CRM114-Status: GOOD ( 18.54 ) 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 Tue, Oct 05, 2021 at 04:02:08PM +0530, Sumit Garg wrote: > Commit 800618f955a9 ("arm64: ftrace: use function_nocfi for ftrace_call") > only fixed address of ftrace_call but address of _mcount needs to be > fixed as well. Use function_nocfi() to get the actual address of _mcount > function as with CONFIG_CFI_CLANG, the compiler replaces function pointers > with jump table addresses which breaks dynamic ftrace as the address of > _mcount is replaced with the address of _mcount.cfi_jt. It might be worth noting that where the toolchain implements patchable-function-entry, we'll use that in preference to regular -pg, and this problem won't apply. i.e. this won't show with recent versions of clang. > Signed-off-by: Sumit Garg This probably wants: Fixes: 9186ad8e66bab6a1 ("arm64: allow CONFIG_CFI_CLANG to be selected") With that: Acked-by: Mark Rutland Mark. > --- > arch/arm64/include/asm/ftrace.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h > index 91fa4baa1a93..347b0cc68f07 100644 > --- a/arch/arm64/include/asm/ftrace.h > +++ b/arch/arm64/include/asm/ftrace.h > @@ -15,7 +15,7 @@ > #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > #define ARCH_SUPPORTS_FTRACE_OPS 1 > #else > -#define MCOUNT_ADDR ((unsigned long)_mcount) > +#define MCOUNT_ADDR ((unsigned long)function_nocfi(_mcount)) > #endif > > /* The BL at the callsite's adjusted rec->ip */ > -- > 2.17.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel