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[209.132.180.67]) by mx.google.com with ESMTP id l67si8285973pfa.321.2018.01.27.08.26.03; Sat, 27 Jan 2018 08:26:17 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@amazon.co.uk header.s=amazon201209 header.b=cOK/EX19; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=amazon.co.uk Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753264AbeA0QY5 (ORCPT + 99 others); Sat, 27 Jan 2018 11:24:57 -0500 Received: from smtp-fw-9102.amazon.com ([207.171.184.29]:58440 "EHLO smtp-fw-9102.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753144AbeA0QYy (ORCPT ); Sat, 27 Jan 2018 11:24:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.co.uk; i=@amazon.co.uk; q=dns/txt; s=amazon201209; t=1517070295; x=1548606295; h=from:to:subject:date:message-id:in-reply-to:references; bh=OXq3lezgru394cm4GIEGjDWl+PBWdbKO5HU163/eal0=; b=cOK/EX19Ut2B40CQu4BcSLmeytAYAb4sF0R0SaoHTVlW5XFuNnM/wN9J jtgU94Kl9KmE4ScGg0wVuMbNN9Cu3ehqK/eWa7zIIOTaYoJ8lAvpM8rTm OV1KSDmRJ2t7KzVaFrla3s8PzB9PO3ZNg1sEnMAw0SeDgYL+tYU0icyjn U=; X-IronPort-AV: E=Sophos;i="5.46,422,1511827200"; d="scan'208";a="590437680" Received: from sea3-co-svc-lb6-vlan3.sea.amazon.com (HELO email-inbound-relay-1e-303d0b0e.us-east-1.amazon.com) ([10.47.22.38]) by smtp-border-fw-out-9102.sea19.amazon.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 27 Jan 2018 16:24:52 +0000 Received: from uc8d3ff76b9bc5848a9cc.ant.amazon.com (iad1-ws-svc-lb91-vlan3.amazon.com [10.0.103.150]) by email-inbound-relay-1e-303d0b0e.us-east-1.amazon.com (8.14.7/8.14.7) with ESMTP id w0RGOftE097659 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 27 Jan 2018 16:24:43 GMT Received: from uc8d3ff76b9bc5848a9cc.ant.amazon.com (localhost [127.0.0.1]) by uc8d3ff76b9bc5848a9cc.ant.amazon.com (8.15.2/8.15.2/Debian-3) with ESMTP id w0RGOeom012550; Sat, 27 Jan 2018 16:24:40 GMT Received: (from dwmw@localhost) by uc8d3ff76b9bc5848a9cc.ant.amazon.com (8.15.2/8.15.2/Submit) id w0RGOe6Z012549; Sat, 27 Jan 2018 16:24:40 GMT From: David Woodhouse To: arjan@linux.intel.com, tglx@linutronix.de, karahmed@amazon.de, x86@kernel.org, linux-kernel@vger.kernel.org, tim.c.chen@linux.intel.com, bp@alien8.de, peterz@infradead.org, pbonzini@redhat.com, ak@linux.intel.com, torvalds@linux-foundation.org, gregkh@linux-foundation.org, dave.hansen@intel.com Subject: [PATCH 3/3] x86/speculation: Simplify indirect_branch_prediction_barrier() Date: Sat, 27 Jan 2018 16:24:34 +0000 Message-Id: <1517070274-12128-4-git-send-email-dwmw@amazon.co.uk> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1517070274-12128-1-git-send-email-dwmw@amazon.co.uk> References: <1517070274-12128-1-git-send-email-dwmw@amazon.co.uk> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Borislav Petkov Make it all a function which does the WRMSR instead of having a hairy inline asm. [dwmw2: export it, fix CONFIG_RETPOLINE issues] Signed-off-by: Borislav Petkov Signed-off-by: David Woodhouse --- arch/x86/include/asm/nospec-branch.h | 13 ++++--------- arch/x86/include/asm/processor.h | 3 +++ arch/x86/kernel/cpu/bugs.c | 6 ++++++ 3 files changed, 13 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index df4ececa..d15d471 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -164,15 +164,10 @@ static inline void vmexit_fill_RSB(void) static inline void indirect_branch_prediction_barrier(void) { - asm volatile(ALTERNATIVE("", - "movl %[msr], %%ecx\n\t" - "movl %[val], %%eax\n\t" - "movl $0, %%edx\n\t" - "wrmsr", - X86_FEATURE_USE_IBPB) - : : [msr] "i" (MSR_IA32_PRED_CMD), - [val] "i" (PRED_CMD_IBPB) - : "eax", "ecx", "edx", "memory"); + alternative_input("", + "call __ibp_barrier", + X86_FEATURE_USE_IBPB, + ASM_NO_INPUT_CLOBBER("eax", "ecx", "edx", "memory")); } #endif /* __ASSEMBLY__ */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 9c18da6..881ca3b 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -970,4 +970,7 @@ bool xen_set_default_idle(void); void stop_this_cpu(void *dummy); void df_debug(struct pt_regs *regs, long error_code); + +void __ibp_barrier(void); + #endif /* _ASM_X86_PROCESSOR_H */ diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 0c6dd43..dd99808 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -303,3 +303,9 @@ ssize_t cpu_show_spectre_v2(struct device *dev, spectre_v2_bad_module ? " - vulnerable module loaded" : ""); } #endif + +void __ibp_barrier(void) +{ + __wrmsr(MSR_IA32_PRED_CMD, PRED_CMD_IBPB, 0); +} +EXPORT_SYMBOL_GPL(__ibp_barrier); -- 2.7.4