From nobody Wed Dec 17 21:28:13 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EDBCBC05052 for ; Wed, 16 Aug 2023 07:56:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242587AbjHPHzj (ORCPT ); Wed, 16 Aug 2023 03:55:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242623AbjHPHzW (ORCPT ); Wed, 16 Aug 2023 03:55:22 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA7EC2698; Wed, 16 Aug 2023 00:55:20 -0700 (PDT) Date: Wed, 16 Aug 2023 07:55:17 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1692172517; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=N1qxCpSoZbwKEx444taO6+ibnP8DLJbSLXKGjD64LcM=; b=AD1zsA8Hhvo/5vRkacyAni3kMaCJzqBCOKCcbZL1VKZe7irOop5YqYR10RhhV0mG9WzoO3 /QPa1STREqc8mvuEVxE1YAUqtup/j76kL9aJMWxKHlz5FzjgLy7ihDTbE6gWvQO9AsjVco w4uEMUZMcutrHyfwP1OnfHQVbMTHsi/UKGgdSLW8Zu7rFfw3nnvGjwd/6s3URJNpNC0QB/ FXmf6NwfBLrzIM4SpAJGz+bxi3lWOakRSD6/iZ4YDUf5OLYVfpi7PmJNqA4vxipZoHXDyV eOaSl91LLpcYJOUI37TBmrhYd+eIlWKPo5y4rUGKrph+Q32n+RBJCfXHrrTE1w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1692172517; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=N1qxCpSoZbwKEx444taO6+ibnP8DLJbSLXKGjD64LcM=; b=S6HX1Fk3h489CjDs4LsgKhlnRlePPO5cf9uzB2dU6w7HC2Y3IHvFxyxJ504BKpyfXsaNgL P7GHX3uc1KUTywDw== From: "tip-bot2 for Peter Zijlstra" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] x86/alternative: Make custom return thunk unconditional Cc: "Peter Zijlstra (Intel)" , "Borislav Petkov (AMD)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20230814121148.775293785@infradead.org> References: <20230814121148.775293785@infradead.org> MIME-Version: 1.0 Message-ID: <169217251717.27769.11292596763604303189.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 095b8303f3835c68ac4a8b6d754ca1c3b6230711 Gitweb: https://git.kernel.org/tip/095b8303f3835c68ac4a8b6d754ca1c3b= 6230711 Author: Peter Zijlstra AuthorDate: Mon, 14 Aug 2023 13:44:30 +02:00 Committer: Borislav Petkov (AMD) CommitterDate: Wed, 16 Aug 2023 09:39:16 +02:00 x86/alternative: Make custom return thunk unconditional There is infrastructure to rewrite return thunks to point to any random thunk one desires, unwrap that from CALL_THUNKS, which up to now was the sole user of that. [ bp: Make the thunks visible on 32-bit and add ifdeffery for the 32-bit builds. ] Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230814121148.775293785@infradead.org --- arch/x86/include/asm/nospec-branch.h | 9 +++++---- arch/x86/kernel/alternative.c | 4 ---- arch/x86/kernel/cpu/bugs.c | 2 ++ 3 files changed, 7 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/no= spec-branch.h index e50db53..b3625cc 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -341,17 +341,18 @@ extern retpoline_thunk_t __x86_indirect_thunk_array[]; extern retpoline_thunk_t __x86_indirect_call_thunk_array[]; extern retpoline_thunk_t __x86_indirect_jump_thunk_array[]; =20 +#ifdef CONFIG_RETHUNK extern void __x86_return_thunk(void); +#else +static inline void __x86_return_thunk(void) {} +#endif + extern void zen_untrain_ret(void); extern void srso_untrain_ret(void); extern void srso_untrain_ret_alias(void); extern void entry_ibpb(void); =20 -#ifdef CONFIG_CALL_THUNKS extern void (*x86_return_thunk)(void); -#else -#define x86_return_thunk (&__x86_return_thunk) -#endif =20 #ifdef CONFIG_CALL_DEPTH_TRACKING extern void __x86_return_skl(void); diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 2dcf3a0..099d58d 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -687,10 +687,6 @@ void __init_or_module noinline apply_retpolines(s32 *s= tart, s32 *end) =20 #ifdef CONFIG_RETHUNK =20 -#ifdef CONFIG_CALL_THUNKS -void (*x86_return_thunk)(void) __ro_after_init =3D &__x86_return_thunk; -#endif - /* * Rewrite the compiler generated return thunk tail-calls. * diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 6c04aef..3bc0d14 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -63,6 +63,8 @@ EXPORT_SYMBOL_GPL(x86_pred_cmd); =20 static DEFINE_MUTEX(spec_ctrl_mutex); =20 +void (*x86_return_thunk)(void) __ro_after_init =3D &__x86_return_thunk; + /* Update SPEC_CTRL MSR and its cached copy unconditionally */ static void update_spec_ctrl(u64 val) {