From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.avm.de (mail.avm.de [212.42.244.94]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B7F9D47C0E6; Thu, 10 Sep 2026 15:42:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.42.244.94 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789054965; cv=none; b=uqZpHhWW4VhWb3IYUuUn0vlNNivFRNnFgYtKLdVf+qlml2jIDTPAS/tqp805UoR9gyXwDah9y62aBfUCPjFM1JTI6uTSgv32DbvidOvzz0QKq+qhkIck+okeqxtbyJV1lzQgTyCPCjC1MvWKQFV3hMy3q9QZIGq1tVKi2fZ5R9Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789054965; c=relaxed/simple; bh=LK8bkV1Vz0floem0tDs4fowSkN+VH/bI8JorqlPfxFI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=vEhI2adnYKEjFaB2+xveoEcnm1S+SPsbE1Uz9LCU86YqeHWXdnnTHw21RWTjXLKf1N5Y8vJuBOuJjYv6HhJjzDQLqleeHV6ioNF47LrlwLAPTvUIWxJ4UlRqZPeVL81F9unhRwSSjy4rQdcpyB9WRSVG3eRdwXDjVwb4Kh3i6S0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=fritz.com; spf=pass smtp.mailfrom=fritz.com; dkim=pass (2048-bit key) header.d=fritz.com header.i=@fritz.com header.b=m2t/gCBQ; arc=none smtp.client-ip=212.42.244.94 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=fritz.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fritz.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fritz.com header.i=@fritz.com header.b="m2t/gCBQ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=fritz.com; s=mail; t=1789054956; bh=LK8bkV1Vz0floem0tDs4fowSkN+VH/bI8JorqlPfxFI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=m2t/gCBQ5Ji+klRB77okzADkIBpOjucABpFdn1joI6CGFroNQ2dok89iTW7zlsgDJ OhupApf9LKIRvcGE2XGbdgRc1L/Cyu778E8qiCt5Mx3N/HSwPKfTDWrLuQBULuYETh DEpZTMKIWNIB95kcOEYyM+KTdXBA1kly0af9dVc2J1yCQpvugpbSIq04iHmdW/EGZ3 Y4A/qaU5/ks6TeFtBhGFS/mS3OdzSq+oJRGgjHfaRsaS82LquTqTSeUDZk3Yd/dQog lg48YsTm0IrzSWtTPbK8Ble4vH9U4bTyk8isOlH6ribTe1cTR6+aKHV2VGyYR9cK7K zTVgF+ct8Jfhw== Received: from [212.42.244.78] (helo=mail.avm.de) by mail.avm.de with ESMTP (eXpurgate 4.57.1) (envelope-from ) id 6aa2cfec-6dc7-7f0000032729-7f000001a7b2-1 for ; Thu, 10 Sep 2026 17:42:36 +0200 Received: from mail-auth.fritz.com (unknown [212.42.244.78]) by mail.avm.de (Postfix) with ESMTPS; Thu, 10 Sep 2026 17:42:36 +0200 (CEST) Date: Thu, 10 Sep 2026 17:42:35 +0200 From: Nicolas Schier To: Nathan Chancellor Cc: "Lorenzo Stoakes (ARM)" , Linus Torvalds , 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: <20260910-translucent-sweet-sidewinder-7acacb@l-nschier-aarch64> 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: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="6NJv2EjhorC/TYUZ" Content-Disposition: inline In-Reply-To: <178901395292.3971858.13236774094648272066.b4-review@b4> Organization: FRITZ! Technology GmbH x-ms-reactions: disallow X-purgate-ID: 149429::1789054956-F1CDF0BC-4895A414/0/0 X-purgate-type: clean X-purgate-size: 2705 X-Notice: Whitelisted X-purgate: This mail is considered clean (visit https://www.eleven.de for further information) X-purgate: clean X-pfmilter: host: postfix-mx-03 mail-id: 9AB3CA045E external: no --6NJv2EjhorC/TYUZ Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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_functio= n)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) > > =20 > > +config CC_HAS_ZERO_INIT_PADDING_BITS > > + def_bool $(cc-option,-fzero-init-padding-bits=3Dall) > > + > > +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) >=20 > 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? Yes, skimming through the patch, I thought about that, too. Moving more=20 cc option checks to Kconfig will make building out-of-tree kmods with a=20 different compiler more dangerous. Maybe we will have to make the=20 warning in Makefile's prepare (external kmods) target a bit louder. > 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? Sounds good, yes. --=20 Nicolas --6NJv2EjhorC/TYUZ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEDv+Fiet06YHnC6RpiMa8nIiabbgFAmqiz+cACgkQiMa8nIia bbgNERAAgCLMWkWnCF5POqjQiZGkZbm/i9SwwH2BVVg0H8Bf+O6WGCZ4YiM0NOu7 6d9EZV95NkDD36Y3vCEaq1/GclFeUn2ET6HEprS7tQsmYbcofxLYoQuMV/5Si/18 jJBz3eksIZYRAnSFGG6K1+Hq3u63l3cV5TmRaquZg76LwJkTjCNsFmfT2wxHP40y LmkyOsw9NiHo2Bm75Bz8ds7EVqHU/wPxCAWBuiw6ervOrw4RR7PURz61DaBGIuOc 9B/HnhACn44debha9z9dUTsDIsPsK2sftFLfgJvD8c1V8vj6D1uhX7Fx/hXRElRA srsyf2q67EuQ8hKIU8sch6rKkD9slQJd0/w2XNQsONffnO9RghF+Qu8dzo9mUusZ l1vYg30SglV5c7m1FlgCvvmvJSppryu6zZw4FgzOUTfcxt6l+VXTm9jaigCWPXbT KAYgvQqNVVgkIAg2WDqyiVTeWQxrxo9ctf3m/6srxI4/AkuGZV/XU2m1QiQJxQ5/ rdm3WGYjD/gVrLPBr6oIoPWDSgP7C4U4kSuZGq1jWAhPeqaa691z+Z5WbRVoVDO/ SEc1cIdDE88/z8QwIEsgmaXaVhnaCiW66Npfh9zP1J+/pQV3kvU4kf9CIEQ6QMDf MPfl1Si0rJA9thzauvNi6Mu6JsUi9FPz7+Oen1Y22eMfv2st6Sc= =TUj9 -----END PGP SIGNATURE----- --6NJv2EjhorC/TYUZ--