From patchwork Wed Jan 22 11:25:16 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 3522631 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 4119FC02DC for ; Wed, 22 Jan 2014 11:31:03 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 1B41720171 for ; Wed, 22 Jan 2014 11:31:02 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C3AB520170 for ; Wed, 22 Jan 2014 11:31:00 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1W5w0Q-0003ds-Rk; Wed, 22 Jan 2014 11:30:03 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1W5w0D-0002ie-K3; Wed, 22 Jan 2014 11:29:49 +0000 Received: from szxga03-in.huawei.com ([119.145.14.66]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1W5vzs-0002dk-JF; Wed, 22 Jan 2014 11:29:32 +0000 Received: from 172.24.2.119 (EHLO szxeml212-edg.china.huawei.com) ([172.24.2.119]) by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued) with ESMTP id AJQ35795; Wed, 22 Jan 2014 19:28:34 +0800 (CST) Received: from SZXEML423-HUB.china.huawei.com (10.82.67.162) by szxeml212-edg.china.huawei.com (172.24.2.181) with Microsoft SMTP Server (TLS) id 14.3.158.1; Wed, 22 Jan 2014 19:28:31 +0800 Received: from LGGEML424-HUB.china.huawei.com (10.72.61.124) by szxeml423-hub.china.huawei.com (10.82.67.162) with Microsoft SMTP Server (TLS) id 14.3.158.1; Wed, 22 Jan 2014 19:28:32 +0800 Received: from kernel-host.huawei (10.107.197.247) by lggeml424-hub.china.huawei.com (10.72.61.124) with Microsoft SMTP Server id 14.3.158.1; Wed, 22 Jan 2014 19:28:17 +0800 From: Wang Nan To: Subject: [PATCH 3/3] ARM: allow kernel to be loaded in middle of phymem Date: Wed, 22 Jan 2014 19:25:16 +0800 Message-ID: <1390389916-8711-4-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1390389916-8711-1-git-send-email-wangnan0@huawei.com> References: <1390389916-8711-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140122_062929_406356_C1302EED X-CRM114-Status: GOOD ( 18.08 ) X-Spam-Score: -3.2 (---) Cc: Wang Nan , stable@vger.kernel.org, linux-kernel@vger.kernel.org, Geng Hui , linux-mm@kvack.org, Eric Biederman , Russell King , Andrew Morton , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch allows the kernel to be loaded at the middle of kernel awared physical memory. Before this patch, users must use mem= or device tree to cheat kernel about the start address of physical memory. This feature is useful in some special cases, for example, building a crash dump kernel. Without it, kernel command line, atag and devicetree must be adjusted carefully, sometimes is impossible. Signed-off-by: Wang Nan Cc: # 3.4+ Cc: Eric Biederman Cc: Russell King Cc: Andrew Morton Cc: Geng Hui --- arch/arm/mm/init.c | 21 ++++++++++++++++++++- arch/arm/mm/mmu.c | 13 +++++++++++++ mm/page_alloc.c | 7 +++++-- 3 files changed, 38 insertions(+), 3 deletions(-) diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 3e8f106..4952726 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -334,9 +334,28 @@ void __init arm_memblock_init(struct meminfo *mi, { int i; - for (i = 0; i < mi->nr_banks; i++) + for (i = 0; i < mi->nr_banks; i++) { memblock_add(mi->bank[i].start, mi->bank[i].size); + /* + * In some special case, for example, building a crushdump + * kernel, we want the kernel to be loaded in the middle of + * physical memory. In such case, the physical memory before + * PHYS_OFFSET is awkward: it can't get directly mapped + * (because its address will be smaller than PAGE_OFFSET, + * disturbs user address space) also can't be mapped as + * HighMem. We reserve such pages here. The only way to access + * those pages is ioremap. + */ + if (mi->bank[i].start < PHYS_OFFSET) { + unsigned long reserv_size = PHYS_OFFSET - + mi->bank[i].start; + if (reserv_size > mi->bank[i].size) + reserv_size = mi->bank[i].size; + memblock_reserve(mi->bank[i].start, reserv_size); + } + } + /* Register the kernel text, kernel data and initrd with memblock. */ #ifdef CONFIG_XIP_KERNEL memblock_reserve(__pa(_sdata), _end - _sdata); diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 580ef2d..2a17c24 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -1308,6 +1308,19 @@ static void __init map_lowmem(void) if (start >= end) break; + /* + * If this memblock contain memory before PAGE_OFFSET, memory + * before PAGE_OFFSET should't get directly mapped, see code + * in create_mapping(). However, memory after PAGE_OFFSET is + * occupyed by kernel and still need to be mapped. + */ + if (__phys_to_virt(start) < PAGE_OFFSET) { + if (__phys_to_virt(end) > PAGE_OFFSET) + start = __virt_to_phys(PAGE_OFFSET); + else + break; + } + map.pfn = __phys_to_pfn(start); map.virtual = __phys_to_virt(start); map.length = end - start; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5248fe0..d2959e3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4840,10 +4840,13 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) */ if (pgdat == NODE_DATA(0)) { mem_map = NODE_DATA(0)->node_mem_map; -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP + /* + * In case of CONFIG_HAVE_MEMBLOCK_NODE_MAP or when kernel + * loaded at the middle of physical memory, mem_map should + * be adjusted. + */ if (page_to_pfn(mem_map) != pgdat->node_start_pfn) mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET); -#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ } #endif #endif /* CONFIG_FLAT_NODE_MEM_MAP */