Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757098AbdLQALA (ORCPT ); Sat, 16 Dec 2017 19:11:00 -0500 Received: from mga11.intel.com ([192.55.52.93]:13132 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756737AbdLQAK5 (ORCPT ); Sat, 16 Dec 2017 19:10:57 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,412,1508828400"; d="scan'208";a="18860314" From: Sai Praneeth Prakhya To: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Sai Praneeth , "Lee, Chun-Yi" , Borislav Petkov , Tony Luck , Andy Lutomirski , "Michael S. Tsirkin" , Ricardo Neri , Matt Fleming , Ard Biesheuvel , Ravi Shankar Subject: [PATCH 0/3] Use mm_struct and switch_mm() instead of manually Date: Sat, 16 Dec 2017 16:05:58 -0800 Message-Id: <1513469158-5638-1-git-send-email-sai.praneeth.prakhya@intel.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2466 Lines: 61 From: Sai Praneeth Presently, in x86, to invoke any efi function like efi_set_virtual_address_map() or any efi_runtime_service() the code path typically involves read_cr3() (save previous pgd), write_cr3() (write efi_pgd) and calling efi function. Likewise after returning from efi function the code path typically involves read_cr3() (save efi_pgd), write_cr3() (write previous pgd). We do this couple of times in efi subsystem of Linux kernel, instead we can use helper function efi_switch_mm() to do this. This improves readability and maintainability. Also, instead of maintaining a separate struct "efi_scratch" to store/restore efi_pgd, we can use mm_struct to do this. I have tested this patch set against LUV (Linux UEFI Validation), so I think I didn't break any existing configurations. I have tested this patch set for 1. x86_64, 2. x86_32, 3. Mixed mode with efi=old_map and for kexec kernel. Please let me know if I have missed any other configurations. Changes in V2: 1. Resolve mm_dropping() issue by not mm_dropping()/mm_grabbing() any mm, as we are not losing/creating any references. Changes in V3: 1. When CPUMASK_OFFSTACK is enabled, switch_mm_irqs_off() sets cpumask by calling cpumask_set_cpu(). This panics kernel as efi_mm is not initialized, therefore initialize efi_mm in efi_alloc_page_tables(). Note: This patch set is based on Linus's tree v4.15-rc3 Sai Praneeth (3): efi: Use efi_mm in x86 as well as ARM x86/efi: Replace efi_pgd with efi_mm.pgd x86/efi: Use efi_switch_mm() rather than manually twiddling with %cr3 arch/x86/include/asm/efi.h | 29 +++++++++--------- arch/x86/platform/efi/efi_64.c | 59 +++++++++++++++++++----------------- arch/x86/platform/efi/efi_thunk_64.S | 2 +- drivers/firmware/efi/arm-runtime.c | 9 ------ drivers/firmware/efi/efi.c | 9 ++++++ include/linux/efi.h | 2 ++ 6 files changed, 57 insertions(+), 53 deletions(-) Signed-off-by: Sai Praneeth Prakhya Cc: Lee, Chun-Yi Cc: Borislav Petkov Cc: Tony Luck Cc: Andy Lutomirski Cc: Michael S. Tsirkin Cc: Ricardo Neri Cc: Matt Fleming Cc: Ard Biesheuvel Cc: Ravi Shankar Tested-by: Bhupesh Sharma -- 2.1.4