From patchwork Thu May 30 22:59:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10969347 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 01D9013AD for ; Thu, 30 May 2019 23:13:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E605728BE3 for ; Thu, 30 May 2019 23:13:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DA2A328BFD; Thu, 30 May 2019 23:13:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7DA4028BE3 for ; Thu, 30 May 2019 23:13:28 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 708832128A649; Thu, 30 May 2019 16:13:28 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=192.55.52.43; helo=mga05.intel.com; envelope-from=dan.j.williams@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id D40342128A638 for ; Thu, 30 May 2019 16:13:26 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 May 2019 16:13:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,532,1549958400"; d="scan'208";a="180115547" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by fmsmga002.fm.intel.com with ESMTP; 30 May 2019 16:13:25 -0700 Subject: [PATCH v2 3/8] efi: Enumerate EFI_MEMORY_SP From: Dan Williams To: linux-efi@vger.kernel.org Date: Thu, 30 May 2019 15:59:38 -0700 Message-ID: <155925717803.3775979.14412010256191901040.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <155925716254.3775979.16716824941364738117.stgit@dwillia2-desk3.amr.corp.intel.com> References: <155925716254.3775979.16716824941364738117.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ard Biesheuvel , linux-nvdimm@lists.01.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP UEFI 2.8 defines an EFI_MEMORY_SP attribute bit to augment the interpretation of the EFI Memory Types as "reserved for a specific purpose". The intent of this bit is to allow the OS to identify precious or scarce memory resources and optionally manage it separately from EfiConventionalMemory. As defined older OSes that do not know about this attribute are permitted to ignore it and the memory will be handled according to the OS default policy for the given memory type. In other words, this "specific purpose" hint is deliberately weaker than EfiReservedMemoryType in that the system continues to operate if the OS takes no action on the attribute. The risk of taking no action is potentially unwanted / unmovable kernel allocations from the designated resource that prevent the full realization of the "specific purpose". For example, consider a system with a high-bandwidth memory pool. Older kernels are permitted to boot and consume that memory as conventional "System-RAM" newer kernels may arrange for that memory to be set aside by the system administrator for a dedicated high-bandwidth memory aware application to consume. Specifically, this mechanism allows for the elimination of scenarios where platform firmware tries to game OS policy by lying about ACPI SLIT values, i.e. claiming that a precious memory resource has a high distance to trigger the OS to avoid it by default. Implement simple detection of the bit for EFI memory table dumps and save the kernel policy for a follow-on change. Cc: Ard Biesheuvel Signed-off-by: Dan Williams Reviewed-by: Ard Biesheuvel --- drivers/firmware/efi/efi.c | 5 +++-- include/linux/efi.h | 1 + 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 55b77c576c42..81db09485881 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -848,15 +848,16 @@ char * __init efi_md_typeattr_format(char *buf, size_t size, if (attr & ~(EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_RO | EFI_MEMORY_WP | EFI_MEMORY_RP | EFI_MEMORY_XP | - EFI_MEMORY_NV | + EFI_MEMORY_NV | EFI_MEMORY_SP | EFI_MEMORY_RUNTIME | EFI_MEMORY_MORE_RELIABLE)) snprintf(pos, size, "|attr=0x%016llx]", (unsigned long long)attr); else snprintf(pos, size, - "|%3s|%2s|%2s|%2s|%2s|%2s|%2s|%3s|%2s|%2s|%2s|%2s]", + "|%3s|%2s|%2s|%2s|%2s|%2s|%2s|%2s|%3s|%2s|%2s|%2s|%2s]", attr & EFI_MEMORY_RUNTIME ? "RUN" : "", attr & EFI_MEMORY_MORE_RELIABLE ? "MR" : "", + attr & EFI_MEMORY_SP ? "SP" : "", attr & EFI_MEMORY_NV ? "NV" : "", attr & EFI_MEMORY_XP ? "XP" : "", attr & EFI_MEMORY_RP ? "RP" : "", diff --git a/include/linux/efi.h b/include/linux/efi.h index 6ebc2098cfe1..91368f5ce114 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -112,6 +112,7 @@ typedef struct { #define EFI_MEMORY_MORE_RELIABLE \ ((u64)0x0000000000010000ULL) /* higher reliability */ #define EFI_MEMORY_RO ((u64)0x0000000000020000ULL) /* read-only */ +#define EFI_MEMORY_SP ((u64)0x0000000000040000ULL) /* special purpose */ #define EFI_MEMORY_RUNTIME ((u64)0x8000000000000000ULL) /* range requires runtime mapping */ #define EFI_MEMORY_DESCRIPTOR_VERSION 1