From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752647AbeBBXLN (ORCPT ); Fri, 2 Feb 2018 18:11:13 -0500 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:17884 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751671AbeBBXKo (ORCPT ); Fri, 2 Feb 2018 18:10:44 -0500 X-IronPort-AV: E=Sophos;i="5.46,451,1511827200"; d="scan'208";a="330369682" From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= To: Ingo Molnar , Thomas Gleixner , x86@kernel.org Cc: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= , Andy Shevchenko , "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: [PATCH v2] x86: e820: Implement a range manipulation operator Date: Sat, 3 Feb 2018 00:10:20 +0100 Message-Id: <20180202231020.15608-1-jschoenh@amazon.de> X-Mailer: git-send-email 2.9.3.1.gcba166c.dirty In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a more versatile memmap= operator, which -- in addition to all the things that were possible before -- allows you to: - redeclare existing ranges -- before, you were limited to adding ranges; - drop any range -- like a mem= for any location; - use any e820 memory type -- not just some predefined ones. The syntax is: memmap=%-+ Size and offset work as usual. The "-" and "+" are optional and their existence determine the behavior: The command works on the specified range of memory limited to type (if specified). This memory is then configured to show up as . If is not specified, the memory is removed from the e820 map. Signed-off-by: Jan H. Schönherr --- v2: Small coding style and typography adjustments Documentation/admin-guide/kernel-parameters.txt | 9 +++++++++ arch/x86/kernel/e820.c | 18 ++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 46b26bfee27b..60926ae3ec06 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2221,6 +2221,15 @@ The memory region may be marked as e820 type 12 (0xc) and is NVDIMM or ADR memory. + memmap=%-+ + [KNL,ACPI] Convert memory within the specified region + from to . If "-" is left + out, the whole region will be marked as , + even if previously unavailable. If "+" is left + out, matching memory will be removed. Types are + specified as e820 types, e.g., 1 = RAM, 2 = reserved, + 3 = ACPI, 12 = PRAM. + memory_corruption_check=0/1 [X86] Some BIOSes seem to corrupt the first 64k of memory when doing things like suspend/resume. diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 71c11ad5643e..6a2cb1442e05 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -924,6 +924,24 @@ static int __init parse_memmap_one(char *p) } else if (*p == '!') { start_at = memparse(p+1, &p); e820__range_add(start_at, mem_size, E820_TYPE_PRAM); + } else if (*p == '%') { + enum e820_type from = 0, to = 0; + + start_at = memparse(p + 1, &p); + if (*p == '-') + from = simple_strtoull(p + 1, &p, 0); + if (*p == '+') + to = simple_strtoull(p + 1, &p, 0); + if (*p != '\0') + return -EINVAL; + if (from && to) + e820__range_update(start_at, mem_size, from, to); + else if (to) + e820__range_add(start_at, mem_size, to); + else if (from) + e820__range_remove(start_at, mem_size, from, 1); + else + e820__range_remove(start_at, mem_size, 0, 0); } else { e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1); } -- 2.9.3.1.gcba166c.dirty