From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5387F231C9C; Mon, 14 Oct 2024 04:28:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728880115; cv=none; b=JwN85wbxOm5xCjLU8iEbQKeQWcVma3ehfGwE3ExnB8fRpopjtZ1TSy8dMSz0BBFcfm+lbXD7f5fcjP+nOJrocYqs8hJGb80Lng1fPYJ5V9hZn1oYaXGMjr7IkcUlL9rPSfQ6gK5f8BDcNh2grs7Um+BBbFbQYv2zlaE0YWv2amA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728880115; c=relaxed/simple; bh=BEBNNN3TM1sEEyjm+HhJUXIc3ue0HOu8SSTt/94QJ+E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gT8nx4EulWq0n3ybXT8gA+OQugz4gKjGcLyXiyLfV0Wa8Stdi/mZyYx6Ji1OUAK/Lt/2G31hCL+IAEDLZlxG1LMWsJUgLSYgIyxRd0hAglRMiYZ3hzAuHc7sTLgNWA1W3ETFtD8NIRMBAS+lwXG+56MTCB/8MWUPIdSq+/m/AtQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HmUBOunb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HmUBOunb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D82BC4CEC3; Mon, 14 Oct 2024 04:28:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728880114; bh=BEBNNN3TM1sEEyjm+HhJUXIc3ue0HOu8SSTt/94QJ+E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HmUBOunbAhoR/a1ntOamSkdFxqkaz+WMR+AXw4+BMMBd2Gxx3hFIJH+Y8TdxCUJVW cb75lGpdArs/Hi8RSJXNWVMcDgTzwwuswF0aQLhf1InunVAnZVyfvcXXMCrLQCgSyg gk/TQ4YqgEdAYuU9b4UriIBbeHJOEGhALXQtIondxCJxTTz900xB1SLP/alfElQ6yQ 8z7baYxwEssQhnlxik5hf+VFrKh3BIDmtioyOB9xlVV+9dRSnoEZ7zviwdp/la3Lf7 DhwuCH7SczW+wyjFJ840g9Tg3s2c1wOF4Kcf55uJ87Dm5gD4tArnJ8OeiSXawcR/qn TnAdmw6h96hWg== Date: Sun, 13 Oct 2024 21:28:33 -0700 From: Eric Biggers To: Ard Biesheuvel Cc: linux-kernel@vger.kernel.org, llvm@lists.linux.dev, keescook@chromium.org, linux-hardening@vger.kernel.org, nathan@kernel.org, Ard Biesheuvel , Josh Poimboeuf , Peter Zijlstra , Jan Beulich , "Jose E. Marchesi" , Kees Cook Subject: Re: [PATCH v3 6/8] crypto: x86/crc32c - Use idiomatic relative jump table Message-ID: <20241014042833.GA20015@sol.localdomain> References: <20241011170847.334429-10-ardb+git@google.com> <20241011170847.334429-16-ardb+git@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241011170847.334429-16-ardb+git@google.com> On Fri, Oct 11, 2024 at 07:08:54PM +0200, Ard Biesheuvel wrote: > diff --git a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S > index bbcff1fb78cb..45b005935194 100644 > --- a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S > +++ b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S > @@ -53,7 +53,7 @@ > .endm > > .macro JMPTBL_ENTRY i > -.quad .Lcrc_\i > +.long .Lcrc_\i - jump_table > .endm > > .macro JNC_LESS_THAN j > @@ -169,7 +169,8 @@ SYM_FUNC_START(crc_pcl) > > ## branch into array > leaq jump_table(%rip), %bufp > - mov (%bufp,%rax,8), %bufp > + movslq (%bufp,%rax,4), len > + addq len, %bufp > JMP_NOSPEC bufp I think it would be much better to just get rid of the jump table here. I have done this at https://lore.kernel.org/linux-crypto/20241014042447.50197-4-ebiggers@kernel.org/ - Eric