From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C245942E421; Fri, 11 Sep 2026 10:26:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789122417; cv=none; b=FZP29g/CVRUUghnDtUonoxZkI/aHONyx//Duearl4opaj4iiVA3e2dcGqtCFN7XVWAKe0KFK+CH33heQwpuFrh/hxILJZz0H+IaXSG7BUVbViPdj/r9Q6D9KSlVXDumQo/WofHnvN6ajHF/h039JmjPeefL5y6Ua9NcsfLeipAw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789122417; c=relaxed/simple; bh=EL18N9TDOXMc0C4mDq6ytDuQ8PKuQqUCUT0UWhcAG5A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Kv5f4QkbNvaDYsKjocwtMGROZkfb8VCS29YImnV23GQ16de9/REgPNCCK+Wd+7zywHJzCjd1EpuIXmWm2QATGK6/uXt7nAok6QZbniHaFNyekukz/pY2aLbmDOka2XzLxdZY27wvFXBrC3iXVJ3v0WafODVCT+dYlmBVOFtipgo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kFDpyBDd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kFDpyBDd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF7391F000FF; Fri, 11 Sep 2026 10:26:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789122409; bh=1b/qcPuJz2i8RCf8tb4bNixsUCkYKAvDGjoKk0PZqp0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=kFDpyBDdyQKph0hYEm2EtP4fmdTwsH5ae1psCQ+iIewwia0k0QRGTo5Nt0s92YAzz FuESck15gxApqv4piu1r+cD9sUZpRnhD48odPTpilTg6mN4SRcykIsTjS7fHCX8phu WGD8JxPG0wpWKwgrbgPdj6tDHS9sTCTympSwtMe3xWCmh5wpolpZwsAVU2dS5NINN+ jVMV1xpdTN3v0SYWjh2cljHWZD+pdGkLEH/BPbnjakFxD/qiHfiegGVUcjKB1C/Q1X aimrZRPcUZh9/wF8gNvM+kOUTOOLvjJd0Z3XSXGfoVs8ZldqVWiDMdG0Zlscj5WDM+ nbPKE+h4wTTEQ== Date: Fri, 11 Sep 2026 11:26:36 +0100 From: "Lorenzo Stoakes (ARM)" To: Nathan Chancellor Cc: Linus Torvalds , Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , Masahiro Yamada , Alexey Gladkov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Arnd Bergmann , Catalin Marinas , Will Deacon , Mark Rutland , Ard Biesheuvel , Ilias Apalodimas , Josh Poimboeuf , Peter Zijlstra , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?B?QmrDtnJu?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , Onur =?utf-8?B?w5Z6a2Fu?= , Jonathan Corbet , Randy Dunlap , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org, Jens Axboe Subject: Re: [PATCH 12/23] kbuild: avoid re-running compiler and linker probes Message-ID: References: <20260908-build-speedup-v1-0-5dc1ac01672d@kernel.org> <20260908-build-speedup-v1-12-5dc1ac01672d@kernel.org> <178901395292.3971858.13236774094648272066.b4-review@b4> 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: <178901395292.3971858.13236774094648272066.b4-review@b4> On Wed, Sep 09, 2026 at 09:19:12PM -0700, Nathan Chancellor wrote: > > diff --git a/init/Kconfig b/init/Kconfig > > index 8583d9f06c52..3c92c87254a3 100644 > > --- a/init/Kconfig > > +++ b/init/Kconfig > > @@ -144,6 +144,44 @@ config CC_HAS_ASSUME > > config CC_HAS_NO_PROFILE_FN_ATTR > > def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) > > > > +config CC_HAS_ZERO_INIT_PADDING_BITS > > + def_bool $(cc-option,-fzero-init-padding-bits=all) > > + > > +config CC_HAS_NO_STACK_CLASH_PROTECTION > > + def_bool $(cc-option,-fno-stack-clash-protection) > > + > > +config CC_HAS_NO_ADDRSIG > > + def_bool $(cc-option,-fno-addrsig) > > I am generally in favor of this proposal since I think these checks > should be cached by Kconfig where possible to clear up running them > twice. That said, I wonder if we should pick a better dumping ground for > these checks other than init/Kconfig. Maybe init/Kconfig.tools or > scripts/Kconfig.tools or something? Yeah makes sense to separate them out so they're not all clumped with unrelated stuff. It feels like init is the right place, having actual substantive Kconfig entries in scripts/ feels a bit weird. I can add an extra patch to move existing entries over before adding these in in the next patch? > > I also worry about backsliding and growing cc-option checks. Should we > update the documentation to state that it is preferrable for these > checks to live in Kconfig so that they can be properly cached? Yeah makes sense. I can add a patch to update the docs too? > > -- > Cheers, > Nathan > -- Cheers, Lorenzo