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=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 8A6CBC43381 for ; Mon, 18 Jan 2021 06:22:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 630A322573 for ; Mon, 18 Jan 2021 06:22:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731648AbhARGVw (ORCPT ); Mon, 18 Jan 2021 01:21:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:54412 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730524AbhARGV0 (ORCPT ); Mon, 18 Jan 2021 01:21:26 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 84E7A22573; Mon, 18 Jan 2021 06:20:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610950845; bh=p0uFxpodUSlLSKHUVPiVgDuBk05sV4ZX/hEEbjugEMs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rADhV9trsX96AXuulR4Ys8Tubj1bTlG1UahlL6S6f4OndiH+dl7Q2i3zoQ8ZKD1PU PvelvTkMPVb3alPgLlSW/adHyTA7HeJ6r+i7sx2omvZt96OiCZNG3RrkdsO1oTnXxT cHTTMSj6RSeFINLEAVQ5HYjVYKA3a0J36coNOG/23j/K1coFLzDMbDlXUi5qCmnP0J WUAJYOJYTeIxhz1HfHncgP9+3sKbR8KWO2dLbDS3XemR/HgkKDvTwxrIvTlLD2COnR 2i0kg1T0L1LqrTfYjj2OFbb0mTQAKwdtwbUROmMa34vz9mMmcQPbVqVkPtez2Fl6e6 /ZjHIPYJhL2uw== From: Andy Lutomirski To: x86@kernel.org Cc: LKML , Krzysztof Mazur , =?UTF-8?q?Krzysztof=20Ol=C4=99dzki?= , Arnd Bergmann , Andy Lutomirski Subject: [PATCH 3/4] x86/fpu: Make the EFI FPU calling convention explicit Date: Sun, 17 Jan 2021 22:20:40 -0800 Message-Id: <49aeb632f155569c75ea3cd78e9028cf7ba776fe.1610950681.git.luto@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org EFI uses kernel_fpu_begin() to conform to the UEFI calling convention. This specifically requires initializing FCW, whereas no sane 64-bit kernel code should use legacy 387 operations that reference FCW. Add KFPU_EFI to make this self-documenting, and use it in the EFI code. This should enable us to safely change the default semantics of kernel_fpu_begin() to stop initializing FCW on 64-bit kernels. Cc: Arnd Bergmann Signed-off-by: Andy Lutomirski --- arch/x86/include/asm/efi.h | 4 ++-- arch/x86/include/asm/fpu/api.h | 7 +++++++ arch/x86/platform/efi/efi_64.c | 2 +- 3 files changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index bc9758ef292e..c60be69a5c82 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -71,7 +71,7 @@ extern unsigned long efi_fw_vendor, efi_config_table; #ifdef CONFIG_X86_32 #define arch_efi_call_virt_setup() \ ({ \ - kernel_fpu_begin(); \ + kernel_fpu_begin_mask(KFPU_EFI); \ firmware_restrict_branch_speculation_start(); \ }) @@ -107,7 +107,7 @@ struct efi_scratch { #define arch_efi_call_virt_setup() \ ({ \ efi_sync_low_kernel_mappings(); \ - kernel_fpu_begin(); \ + kernel_fpu_begin_mask(KFPU_EFI); \ firmware_restrict_branch_speculation_start(); \ efi_switch_mm(&efi_mm); \ }) diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index 133907a200ef..e95a06845443 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -25,6 +25,13 @@ #define KFPU_XYZMM _BITUL(1) /* MXCSR will be initialized */ #define KFPU_MMX 0 /* nothing gets initialized */ +/* + * The UEFI calling convention (UEFI spec 2.3.2 and 2.3.4) requires + * that FCW (32-bit and 64-bit) and MXCSR (64-bit) must be initialized + * prior to calling UEFI code. + */ +#define KFPU_EFI (KFPU_387 | KFPU_XYZMM) + extern void kernel_fpu_begin_mask(unsigned int kfpu_mask); extern void kernel_fpu_end(void); extern bool irq_fpu_usable(void); diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 8f5759df7776..c304c8da862b 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -848,7 +848,7 @@ efi_set_virtual_address_map(unsigned long memory_map_size, virtual_map); efi_switch_mm(&efi_mm); - kernel_fpu_begin(); + kernel_fpu_begin_mask(KFPU_EFI); /* Disable interrupts around EFI calls: */ local_irq_save(flags); -- 2.29.2