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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 0C636C352A3 for ; Tue, 11 Feb 2020 13:58:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DECDA2086A for ; Tue, 11 Feb 2020 13:58:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729475AbgBKNxQ (ORCPT ); Tue, 11 Feb 2020 08:53:16 -0500 Received: from 8bytes.org ([81.169.241.247]:51850 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729436AbgBKNxN (ORCPT ); Tue, 11 Feb 2020 08:53:13 -0500 Received: by theia.8bytes.org (Postfix, from userid 1000) id 6380C646; Tue, 11 Feb 2020 14:53:08 +0100 (CET) From: Joerg Roedel To: x86@kernel.org Cc: hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Thomas Hellstrom , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, Joerg Roedel , Joerg Roedel Subject: [PATCH 07/62] x86/boot/compressed/64: Disable red-zone usage Date: Tue, 11 Feb 2020 14:52:01 +0100 Message-Id: <20200211135256.24617-8-joro@8bytes.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200211135256.24617-1-joro@8bytes.org> References: <20200211135256.24617-1-joro@8bytes.org> 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. 10 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, so disable it for the pre-decompression boot code. Signed-off-by: Joerg Roedel --- arch/x86/boot/Makefile | 2 +- arch/x86/boot/compressed/Makefile | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index 012b82fc8617..8f55e4ce1ccc 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -65,7 +65,7 @@ clean-files += 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)/=) GCOV_PROFILE := n diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 26050ae0b27e..e186cc0b628d 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -30,7 +30,7 @@ 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 += $(call cc-option,-ffreestanding) @@ -87,7 +87,7 @@ endif vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o -$(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone +$(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar vmlinux-objs-$(CONFIG_EFI_STUB) += $(obj)/eboot.o \ $(objtree)/drivers/firmware/efi/libstub/lib.a -- 2.17.1