From nobody Sat Apr 11 07:07:33 2026 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 D3347C6FA8E for ; Thu, 2 Mar 2023 05:51:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230056AbjCBFv4 (ORCPT ); Thu, 2 Mar 2023 00:51:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229965AbjCBFva (ORCPT ); Thu, 2 Mar 2023 00:51:30 -0500 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54D0C4E5E8; Wed, 1 Mar 2023 21:51:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1677736260; x=1709272260; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=voFQVjFSRNzDP3of726cqSfwzN6e3VmowuyZWcsyuKM=; b=gjEX5fzftlhKADWO1Mdk4T6ESyjkokRqYTUmr33Gpwu4gZvzuRWbXkkG lii4AJWxJlatWFWQqfGNmKKbRFyvTcFrH96jB92TD68cKdvP0oAwfe6rR Y84C4Dym6rwsKtW1AYFRdf0HI3qH0jlzGoaYpFC1hev0OE+PkDJUDgGQX u8P+90BgKutUuUVEeVzrpgZ6TS41qonA5v1j5tW8g+IyBXvaGernsS3IU Erw9jHksdGXk5VEsUAJZZJbekttBPnEZaFoLfA8DvvX9nPFkB8FzIo2RR yD/eZXUslpmp7Y4h3k8SdFGxC5TW67OVqPzfKuZREkSn7+4Nh3LH7zqoF Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10636"; a="420887199" X-IronPort-AV: E=Sophos;i="5.98,226,1673942400"; d="scan'208";a="420887199" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Mar 2023 21:50:52 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10636"; a="920530921" X-IronPort-AV: E=Sophos;i="5.98,226,1673942400"; d="scan'208";a="920530921" Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga006.fm.intel.com with ESMTP; 01 Mar 2023 21:50:48 -0800 From: Xin Li To: linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, andrew.cooper3@citrix.com, seanjc@google.com, pbonzini@redhat.com, ravi.v.shankar@intel.com Subject: [PATCH v4 16/34] x86/fred: reserve space for the FRED stack frame Date: Wed, 1 Mar 2023 21:24:53 -0800 Message-Id: <20230302052511.1918-17-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230302052511.1918-1-xin3.li@intel.com> References: <20230302052511.1918-1-xin3.li@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "H. Peter Anvin (Intel)" When using FRED, reserve space at the top of the stack frame, just like i386 does. A future version of FRED might have dynamic frame sizes, though, in which case it might be necessary to make TOP_OF_KERNEL_STACK_PADDING a variable instead of a constant. Signed-off-by: H. Peter Anvin (Intel) Tested-by: Shan Kang Signed-off-by: Xin Li --- arch/x86/include/asm/thread_info.h | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thre= ad_info.h index f1cccba52eb9..998483078d5f 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -31,7 +31,9 @@ * In vm86 mode, the hardware frame is much longer still, so add 16 * bytes to make room for the real-mode segments. * - * x86_64 has a fixed-length stack frame. + * x86-64 has a fixed-length stack frame, but it depends on whether + * or not FRED is enabled. Future versions of FRED might make this + * dynamic, but for now it is always 2 words longer. */ #ifdef CONFIG_X86_32 # ifdef CONFIG_VM86 @@ -39,8 +41,12 @@ # else # define TOP_OF_KERNEL_STACK_PADDING 8 # endif -#else -# define TOP_OF_KERNEL_STACK_PADDING 0 +#else /* x86-64 */ +# ifdef CONFIG_X86_FRED +# define TOP_OF_KERNEL_STACK_PADDING (2*8) +# else +# define TOP_OF_KERNEL_STACK_PADDING 0 +# endif #endif =20 /* --=20 2.34.1