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 AEE931ACE12; Fri, 24 Jan 2025 16:47:55 +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=1737737275; cv=none; b=DVp7unOSJ1JtgRpyH+riHUCg6e7C4aiTF72f9xr1cw3MZQQ/tLeiUvOo42RdHlKNqj7BjGRuwveQkaizIFRCDDFtimnRA+fPEALOnSDorLa2g/AJvE7ARVkJoQ2JeFsdyoZJyKUUF2awRPP9T+Gz7uBKszGPNbaoK7VaVx3eCSs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737737275; c=relaxed/simple; bh=bNqZ4+ItrUuElCv/vSiC9ONDNWCJu2oO44CS2/EWYdA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nLHKZVolI/ka8hvypjBDEH3+3njtYWHktG1Sm1TlGQJPVb7+2f3EvxhGJfZLZTVOI+aLjqOGzv4FwbS0nAKaBpb2Mp60+RW+ysfzV9OaaTkxfUbp83AcKfFYYcYBGn+hjQzTJaS06+SH2nPKn7AT7hAD/hZe+xxfeYmSSsxiYck= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dP0PfN4U; 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="dP0PfN4U" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E5E6C4CED2; Fri, 24 Jan 2025 16:47:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737737275; bh=bNqZ4+ItrUuElCv/vSiC9ONDNWCJu2oO44CS2/EWYdA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dP0PfN4UoewMqc2BRSI5aTRHCyTbertPjY829spBAmQAD2udIypBehz16Naao8ikj NKck8+7XV4VDWLChVsy3CgmDJxPPkjmpkRS1KAv3k7Cq+GKOlXqZlqFBExrZ4yqKzk R4L8tfDOw1bDH/WT6nnTPUnBoyl7TKbsQP62brBBMVRJJpn4biuIE7I2zFPzG5CEOS 5e6Ui5tzYCpUeUfP4Z+5vnGuASJIb3++QEtMzpefI23Girb/FlHY9gfCXf0TEJwSuK y2TxOg0u5QYd27LqZ5S0wDaWflTq8HTqVVmQ0PygtxLaAg/hKqb19/zVsESbJj6QJA 4FTesoGhFwjLQ== Date: Fri, 24 Jan 2025 08:47:52 -0800 From: Josh Poimboeuf To: Jens Remus Cc: x86@kernel.org, Peter Zijlstra , Steven Rostedt , Ingo Molnar , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, Indu Bhagat , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , linux-perf-users@vger.kernel.org, Mark Brown , linux-toolchains@vger.kernel.org, Jordan Rome , Sam James , linux-trace-kernel@vger.kernel.org, Andrii Nakryiko , Mathieu Desnoyers , Florian Weimer , Andy Lutomirski , Masami Hiramatsu , Weinan Liu , Heiko Carstens , Vasily Gorbik Subject: Re: [PATCH v4 05/39] x86/asm: Avoid emitting DWARF CFI for non-VDSO Message-ID: <20250124164752.hmwq6mctc6nf7uni@jpoimboe> References: <0c6c20d81164ba1dd375465f31bd51a8e1af164d.1737511963.git.jpoimboe@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Fri, Jan 24, 2025 at 05:08:57PM +0100, Jens Remus wrote: > On 22.01.2025 03:30, Josh Poimboeuf wrote: > > -#ifndef BUILD_VDSO > > - /* > > - * Emit CFI data in .debug_frame sections, not .eh_frame sections. > > - * The latter we currently just discard since we don't do DWARF > > - * unwinding at runtime. So only the offline DWARF information is > > - * useful to anyone. Note we should not use this directive if we > > - * ever decide to enable DWARF unwinding at runtime. > > - */ > > - .cfi_sections .debug_frame > > -#else > > - /* > > - * For the vDSO, emit both runtime unwind information and debug > > - * symbols for the .dbg file. > > - */ > > - .cfi_sections .eh_frame, .debug_frame > > -#endif > > +#else /* !BUILD_VDSO */ > > + > > Did you remove ".cfi_sections .debug_frame" on purpose from the > !BUILD_VDSO path compared to V3? Yes, since non-VDSO assembly files won't be emitting any .cfi, there's no .debug_frame to output anyway. > Presumably to not only not emit DWARF CFI from assembler, but any > source? This only impacts assembly files, notice the __ASSEMBLY__ check at the top of the file. -- Josh