From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932509AbdJYKOj (ORCPT ); Wed, 25 Oct 2017 06:14:39 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:53898 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932228AbdJYKOe (ORCPT ); Wed, 25 Oct 2017 06:14:34 -0400 X-Google-Smtp-Source: ABhQp+S9ou5OcZgZkIRYYh5mAqpH7Mh7dBG0ftrWbsk4Q7r/IN3rWXHnabssfSXIyhxwPEgr1K/apA== From: Ard Biesheuvel To: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, Matt Fleming Subject: [PATCH 2/2] arm64: efi: ignore EFI_MEMORY_XP attribute if RP and/or WP are set Date: Wed, 25 Oct 2017 11:14:19 +0100 Message-Id: <20171025101419.26369-3-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171025101419.26369-1-ard.biesheuvel@linaro.org> References: <20171025101419.26369-1-ard.biesheuvel@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The UEFI memory map is a bit vague about how to interpret the EFI_MEMORY_XP attribute when it is combined with EFI_MEMORY_RP and/or EFI_MEMORY_WP, which have retroactively been redefined as cacheability attributes rather than permission attributes. So let's ignore EFI_MEMORY_XP if _RP and/or _WP are also set. In this case, it is likely that they are being used to describe the capability of the region (i.e., whether it has the controls to reconfigure it as non-executable) rather than the nature of the contents of the region (i.e., whether it contains data that we will never attempt to execute) Reported-by: Stephen Boyd Tested-by: Stephen Boyd Cc: Matt Fleming Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/efi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c index 82cd07592519..f85ac58d08a3 100644 --- a/arch/arm64/kernel/efi.c +++ b/arch/arm64/kernel/efi.c @@ -48,7 +48,9 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md) return pgprot_val(PAGE_KERNEL_ROX); /* RW- */ - if (attr & EFI_MEMORY_XP || type != EFI_RUNTIME_SERVICES_CODE) + if (((attr & (EFI_MEMORY_RP | EFI_MEMORY_WP | EFI_MEMORY_XP)) == + EFI_MEMORY_XP) || + type != EFI_RUNTIME_SERVICES_CODE) return pgprot_val(PAGE_KERNEL); /* RWX */ -- 2.11.0