From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63FFEC388F9 for ; Mon, 23 Nov 2020 13:46:38 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DA6D22075A for ; Mon, 23 Nov 2020 13:46:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="pFHfdZa+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DA6D22075A Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.34360.65358 (Exim 4.92) (envelope-from ) id 1khCAk-0002Ji-KA; Mon, 23 Nov 2020 13:46:26 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 34360.65358; Mon, 23 Nov 2020 13:46:26 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1khCAk-0002Ja-Gs; Mon, 23 Nov 2020 13:46:26 +0000 Received: by outflank-mailman (input) for mailman id 34360; Mon, 23 Nov 2020 13:46:25 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1khCAj-0002JO-Lw for xen-devel@lists.xenproject.org; Mon, 23 Nov 2020 13:46:25 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 985749d8-5b92-4062-a5bc-1b08fd081024; Mon, 23 Nov 2020 13:46:24 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id EF7CAAC23; Mon, 23 Nov 2020 13:46:23 +0000 (UTC) Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1khCAj-0002JO-Lw for xen-devel@lists.xenproject.org; Mon, 23 Nov 2020 13:46:25 +0000 X-Inumbo-ID: 985749d8-5b92-4062-a5bc-1b08fd081024 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 985749d8-5b92-4062-a5bc-1b08fd081024; Mon, 23 Nov 2020 13:46:24 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1606139184; h=from:from:reply-to: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=vDqW5RTe5KhXmgkVYzMyjwwQbOdd2k70RljFlzhoaCU=; b=pFHfdZa+cuPa90DerVTHkiQI8Vm/AJhQHtwMNNMS0fTtFJdermuXy7tWML8godkCDBjkbv f0wuDWwgEu5nU6CCIaEXvaVf0QitqWL67X+iqppFshfVSoYWej/fW5yw1B1jVe5lIkeV4Z T/l5zpYzVLCjODWlInwYnEy8sH+lBlo= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id EF7CAAC23; Mon, 23 Nov 2020 13:46:23 +0000 (UTC) Subject: [PATCH v3 7/7] x86: reduce CET-SS related #ifdef-ary From: Jan Beulich To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , Wei Liu , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= References: <8e7d1472-dd37-8ed3-ec2f-ce954ea61dfd@suse.com> Message-ID: <3b55e0f7-a9ad-73f4-bf2c-99053f7886e3@suse.com> Date: Mon, 23 Nov 2020 14:46:23 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <8e7d1472-dd37-8ed3-ec2f-ce954ea61dfd@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Commit b586a81b7a90 ("x86/CET: Fix build following c/s 43b98e7190") had to introduce a number of #ifdef-s to make the build work with older tool chains. Introduce an assembler macro covering for tool chains not knowing of CET-SS, allowing some conditionals where just SETSSBSY is the problem to be dropped again. No change to generated code. Signed-off-by: Jan Beulich Reviewed-by: Roger Pau Monné --- v4: Move to end of series. --- Now that I've done this I'm no longer sure which direction is better to follow: On one hand this introduces dead code (even if just NOPs) into CET-SS-disabled builds. Otoh this is a step towards breaking the tool chain version dependency of the feature. I've also dropped conditionals around bigger chunks of code; while I think that's preferable, I'm open to undo those parts. --- a/xen/arch/x86/boot/x86_64.S +++ b/xen/arch/x86/boot/x86_64.S @@ -31,7 +31,6 @@ ENTRY(__high_start) jz .L_bsp /* APs. Set up shadow stacks before entering C. */ -#ifdef CONFIG_XEN_SHSTK testl $cpufeat_mask(X86_FEATURE_XEN_SHSTK), \ CPUINFO_FEATURE_OFFSET(X86_FEATURE_XEN_SHSTK) + boot_cpu_data(%rip) je .L_ap_shstk_done @@ -55,7 +54,6 @@ ENTRY(__high_start) mov $XEN_MINIMAL_CR4 | X86_CR4_CET, %ecx mov %rcx, %cr4 setssbsy -#endif .L_ap_shstk_done: call start_secondary --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -668,7 +668,7 @@ static void __init noreturn reinit_bsp_s stack_base[0] = stack; memguard_guard_stack(stack); - if ( IS_ENABLED(CONFIG_XEN_SHSTK) && cpu_has_xen_shstk ) + if ( cpu_has_xen_shstk ) { wrmsrl(MSR_PL0_SSP, (unsigned long)stack + (PRIMARY_SHSTK_SLOT + 1) * PAGE_SIZE - 8); --- a/xen/arch/x86/x86_64/compat/entry.S +++ b/xen/arch/x86/x86_64/compat/entry.S @@ -197,9 +197,7 @@ ENTRY(cr4_pv32_restore) /* See lstar_enter for entry register state. */ ENTRY(cstar_enter) -#ifdef CONFIG_XEN_SHSTK ALTERNATIVE "", "setssbsy", X86_FEATURE_XEN_SHSTK -#endif /* sti could live here when we don't switch page tables below. */ CR4_PV32_RESTORE movq 8(%rsp),%rax /* Restore %rax. */ --- a/xen/arch/x86/x86_64/entry.S +++ b/xen/arch/x86/x86_64/entry.S @@ -236,9 +236,7 @@ iret_exit_to_guest: * %ss must be saved into the space left by the trampoline. */ ENTRY(lstar_enter) -#ifdef CONFIG_XEN_SHSTK ALTERNATIVE "", "setssbsy", X86_FEATURE_XEN_SHSTK -#endif /* sti could live here when we don't switch page tables below. */ movq 8(%rsp),%rax /* Restore %rax. */ movq $FLAT_KERNEL_SS,8(%rsp) @@ -272,9 +270,7 @@ ENTRY(lstar_enter) jmp test_all_events ENTRY(sysenter_entry) -#ifdef CONFIG_XEN_SHSTK ALTERNATIVE "", "setssbsy", X86_FEATURE_XEN_SHSTK -#endif /* sti could live here when we don't switch page tables below. */ pushq $FLAT_USER_SS pushq $0 --- a/xen/include/asm-x86/asm-defns.h +++ b/xen/include/asm-x86/asm-defns.h @@ -8,6 +8,12 @@ .endm #endif +#ifndef CONFIG_HAS_AS_CET_SS +.macro setssbsy + .byte 0xf3, 0x0f, 0x01, 0xe8 +.endm +#endif + .macro INDIRECT_BRANCH insn:req arg:req /* * Create an indirect branch. insn is one of call/jmp, arg is a single