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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 85848C433E5 for ; Tue, 14 Jul 2020 12:17:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53AA62068F for ; Tue, 14 Jul 2020 12:17:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728810AbgGNMRk (ORCPT ); Tue, 14 Jul 2020 08:17:40 -0400 Received: from 8bytes.org ([81.169.241.247]:52918 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726630AbgGNMKk (ORCPT ); Tue, 14 Jul 2020 08:10:40 -0400 Received: from cap.home.8bytes.org (p5b006776.dip0.t-ipconnect.de [91.0.103.118]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by theia.8bytes.org (Postfix) with ESMTPSA id DEC3E5D1; Tue, 14 Jul 2020 14:10:38 +0200 (CEST) From: Joerg Roedel To: x86@kernel.org Cc: Joerg Roedel , Joerg Roedel , hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Sean Christopherson , Martin Radev , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH v4 11/75] x86/boot/compressed/64: Disable red-zone usage Date: Tue, 14 Jul 2020 14:08:13 +0200 Message-Id: <20200714120917.11253-12-joro@8bytes.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714120917.11253-1-joro@8bytes.org> References: <20200714120917.11253-1-joro@8bytes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joerg Roedel The x86-64 ABI defines a red-zone on the stack: The 128-byte area beyond the location pointed to by %rsp is considered to be reserved and shall not be modified by signal or interrupt handlers. Therefore, functions may use this area for temporary data that is not needed across function calls. In particular, leaf functions may use this area for their entire stack frame, rather than adjusting the stack pointer in the prologue and epilogue. This area is known as the red zone. This is not compatible with exception handling, because the IRET frame written by the hardware at the stack pointer and the functions to handle the exception will overwrite the temporary variables of the interrupted function, causing undefined behavior. So disable red-zones for the pre-decompression boot code. Signed-off-by: Joerg Roedel --- arch/x86/boot/Makefile | 2 +- arch/x86/boot/compressed/Makefile | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index fe605205b4ce..4d6a16a47e9f 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -66,7 +66,7 @@ targets += cpustr.h # --------------------------------------------------------------------------- -KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP +KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP -mno-red-zone KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 7619742f91c9..95ac85b8ef27 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -32,7 +32,7 @@ KBUILD_CFLAGS := -m$(BITS) -O2 KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC) KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING cflags-$(CONFIG_X86_32) := -march=i386 -cflags-$(CONFIG_X86_64) := -mcmodel=small +cflags-$(CONFIG_X86_64) := -mcmodel=small -mno-red-zone KBUILD_CFLAGS += $(cflags-y) KBUILD_CFLAGS += -mno-mmx -mno-sse KBUILD_CFLAGS += $(call cc-option,-ffreestanding) -- 2.27.0 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: [PATCH v4 11/75] x86/boot/compressed/64: Disable red-zone usage Date: Tue, 14 Jul 2020 14:08:13 +0200 Message-ID: <20200714120917.11253-12-joro@8bytes.org> References: <20200714120917.11253-1-joro@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200714120917.11253-1-joro@8bytes.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: x86@kernel.org Cc: Juergen Gross , Tom Lendacky , Joerg Roedel , Mike Stunes , Kees Cook , kvm@vger.kernel.org, Peter Zijlstra , Cfir Cohen , Joerg Roedel , Dave Hansen , linux-kernel@vger.kernel.org, Sean Christopherson , virtualization@lists.linux-foundation.org, Martin Radev , Masami Hiramatsu , Andy Lutomirski , hpa@zytor.com, Erdem Aktas , David Rientjes , Dan Williams , Jiri Slaby List-Id: virtualization@lists.linuxfoundation.org From: Joerg Roedel The x86-64 ABI defines a red-zone on the stack: The 128-byte area beyond the location pointed to by %rsp is considered to be reserved and shall not be modified by signal or interrupt handlers. Therefore, functions may use this area for temporary data that is not needed across function calls. In particular, leaf functions may use this area for their entire stack frame, rather than adjusting the stack pointer in the prologue and epilogue. This area is known as the red zone. This is not compatible with exception handling, because the IRET frame written by the hardware at the stack pointer and the functions to handle the exception will overwrite the temporary variables of the interrupted function, causing undefined behavior. So disable red-zones for the pre-decompression boot code. Signed-off-by: Joerg Roedel --- arch/x86/boot/Makefile | 2 +- arch/x86/boot/compressed/Makefile | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index fe605205b4ce..4d6a16a47e9f 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -66,7 +66,7 @@ targets += cpustr.h # --------------------------------------------------------------------------- -KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP +KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP -mno-red-zone KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 7619742f91c9..95ac85b8ef27 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -32,7 +32,7 @@ KBUILD_CFLAGS := -m$(BITS) -O2 KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC) KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING cflags-$(CONFIG_X86_32) := -march=i386 -cflags-$(CONFIG_X86_64) := -mcmodel=small +cflags-$(CONFIG_X86_64) := -mcmodel=small -mno-red-zone KBUILD_CFLAGS += $(cflags-y) KBUILD_CFLAGS += -mno-mmx -mno-sse KBUILD_CFLAGS += $(call cc-option,-ffreestanding) -- 2.27.0