From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751649AbeBAXNb (ORCPT ); Thu, 1 Feb 2018 18:13:31 -0500 Received: from smtp-fw-4101.amazon.com ([72.21.198.25]:11523 "EHLO smtp-fw-4101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751508AbeBAXNZ (ORCPT ); Thu, 1 Feb 2018 18:13:25 -0500 X-IronPort-AV: E=Sophos;i="5.46,444,1511827200"; d="scan'208";a="706380342" 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?= , "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: [PATCH] x86: e820: Implement a range manipulation operator Date: Fri, 2 Feb 2018 00:13:13 +0100 Message-Id: <20180201231313.28458-1-jschoenh@amazon.de> X-Mailer: git-send-email 2.9.3.1.gcba166c.dirty 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 --- 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..94609eaff2a9 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, eg, 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..cd22c6a07632 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