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 A1851C47258 for ; Tue, 23 Jan 2024 09:54:31 +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-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=hYTe+ZHD5YmZY1qL2qUfqYuCxlOJyai238xSE36edwk=; b=r1IWArXDXSxh1J cJZlCOCUXEvAvij+4Tq+Ysbh062MUZrY+x/2A5P7ob0PqPtieKt2XIkzbLHlvgBjpjGohM4Jf+HOT kg9VS/9f4AADwDKOWydg/n36jx83TzBU3AxP5Rpg3N2tEJ2TuNRN0ub+0YW73MzMNeOrmFXCXRwmo GqgXaF9jkrhOBTcv3Ydlm2rtb0N991VxpCP7Ny4j7aXX/0vFdj/IeefkYmRbQcYGHzZ6Fiqa/Ux2r pe3A8510FbQ0xhDbj6gAC2oRS2ilmdrqxPO7Vkiane0NLZ5bBLod/F0bcwgigoI590/re69O+c7Qi DgWZ/val8exTM4sRvUjQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rSDTp-00FpnC-1K; Tue, 23 Jan 2024 09:54:05 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rSDTm-00FpmH-1O for linux-arm-kernel@lists.infradead.org; Tue, 23 Jan 2024 09:54:04 +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 15AEB1FB; Tue, 23 Jan 2024 01:54:41 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.48.47]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E68F13F5A1; Tue, 23 Jan 2024 01:53:53 -0800 (PST) Date: Tue, 23 Jan 2024 09:53:51 +0000 From: Mark Rutland To: Kees Cook Cc: linux-hardening@vger.kernel.org, Will Deacon , Peter Zijlstra , Boqun Feng , Catalin Marinas , linux-arm-kernel@lists.infradead.org, "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: Re: [PATCH 11/82] arm64: atomics: lse: Silence intentional wrapping addition Message-ID: References: <20240122235208.work.748-kees@kernel.org> <20240123002814.1396804-11-keescook@chromium.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240123002814.1396804-11-keescook@chromium.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240123_015402_520268_2462E819 X-CRM114-Status: GOOD ( 12.97 ) 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 Mon, Jan 22, 2024 at 04:26:46PM -0800, Kees Cook wrote: > Annotate atomic_add_return() and atomic_sub_return() to avoid signed > overflow instrumentation. They are expected to wrap around. > > Cc: Will Deacon > Cc: Peter Zijlstra > Cc: Boqun Feng > Cc: Mark Rutland > Cc: Catalin Marinas > Cc: linux-arm-kernel@lists.infradead.org > Signed-off-by: Kees Cook > --- > arch/arm64/include/asm/atomic_lse.h | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/include/asm/atomic_lse.h b/arch/arm64/include/asm/atomic_lse.h > index 87f568a94e55..30572458d702 100644 > --- a/arch/arm64/include/asm/atomic_lse.h > +++ b/arch/arm64/include/asm/atomic_lse.h > @@ -79,13 +79,13 @@ ATOMIC_FETCH_OP_SUB( ) > #undef ATOMIC_FETCH_OP_SUB > > #define ATOMIC_OP_ADD_SUB_RETURN(name) \ > -static __always_inline int \ > +static __always_inline __signed_wrap int \ > __lse_atomic_add_return##name(int i, atomic_t *v) \ > { \ > return __lse_atomic_fetch_add##name(i, v) + i; \ > } \ I'd strongly prefer using add_wrap() rather than annotating the function, i.e. make this: static __always_inline int \ __lse_atomic_add_return##name(int i, atomic_t *v) \ { \ return add_wrap(__lse_atomic_fetch_add##name(i, v), i); \ } \ Likewise for the other instances below. With that, this looks fine to me. Mark. > \ > -static __always_inline int \ > +static __always_inline __signed_wrap int \ > __lse_atomic_sub_return##name(int i, atomic_t *v) \ > { \ > return __lse_atomic_fetch_sub(i, v) - i; \ > @@ -186,13 +186,13 @@ ATOMIC64_FETCH_OP_SUB( ) > #undef ATOMIC64_FETCH_OP_SUB > > #define ATOMIC64_OP_ADD_SUB_RETURN(name) \ > -static __always_inline long \ > +static __always_inline __signed_wrap long \ > __lse_atomic64_add_return##name(s64 i, atomic64_t *v) \ > { \ > return __lse_atomic64_fetch_add##name(i, v) + i; \ > } \ > \ > -static __always_inline long \ > +static __always_inline __signed_wrap long \ > __lse_atomic64_sub_return##name(s64 i, atomic64_t *v) \ > { \ > return __lse_atomic64_fetch_sub##name(i, v) - i; \ > -- > 2.34.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel