From patchwork Thu Jun 23 17:54:48 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geoff Levand X-Patchwork-Id: 9195709 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4F2236075F for ; Thu, 23 Jun 2016 17:59:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 419882845F for ; Thu, 23 Jun 2016 17:59:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3636728466; Thu, 23 Jun 2016 17:59:38 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3AD242845F for ; Thu, 23 Jun 2016 17:59:37 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bG8t8-00022L-Lj; Thu, 23 Jun 2016 17:58:02 +0000 Received: from merlin.infradead.org ([2001:4978:20e::2]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bG8q6-0005uu-PE; Thu, 23 Jun 2016 17:54:54 +0000 Received: from geoff by merlin.infradead.org with local (Exim 4.85_2 #1 (Red Hat Linux)) id 1bG8q0-0003RM-Oz; Thu, 23 Jun 2016 17:54:48 +0000 Message-Id: <43a9f5735dff7aceef7611412460d53930ebb8e3.1466702804.git.geoff@infradead.org> In-Reply-To: References: From: Geoff Levand Patch-Date: Wed, 19 Aug 2015 16:43:42 +0900 Subject: [PATCH v20 10/14] arm64: kdump: add kdump support To: Catalin Marinas , Will Deacon Date: Thu, 23 Jun 2016 17:54:48 +0000 X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , marc.zyngier@arm.com, kexec@lists.infradead.org, AKASHI Takahiro , James Morse , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: AKASHI Takahiro On crash dump kernel, all the information about primary kernel's system memory (core image) is available in elf core header. The primary kernel will set aside this header with reserve_elfcorehdr() at boot time and inform crash dump kernel of its location via a new device-tree property, "linux,elfcorehdr". Please note that all other architectures use traditional "elfcorehdr=" kernel parameter for this purpose. Then crash dump kernel will access the primary kernel's memory with copy_oldmem_page(), which reads one page by ioremap'ing it since it does not reside in linear mapping on crash dump kernel. We also need our own elfcorehdr_read() here since the header is placed within crash dump kernel's usable memory. Signed-off-by: AKASHI Takahiro --- arch/arm64/Kconfig | 11 +++++++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/crash_dump.c | 71 ++++++++++++++++++++++++++++++++++++++++++ arch/arm64/mm/init.c | 54 ++++++++++++++++++++++++++++++++ 4 files changed, 137 insertions(+) create mode 100644 arch/arm64/kernel/crash_dump.c diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 330786d..b5e0eb4 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -674,6 +674,17 @@ config KEXEC but it is independent of the system firmware. And like a reboot you can start any kernel with it, not just Linux. +config CRASH_DUMP + bool "Build kdump crash kernel" + help + Generate crash dump after being started by kexec. This should + be normally only set in special crash dump kernels which are + loaded in the main kernel with kexec-tools into a specially + reserved region and then later executed after a crash by + kdump/kexec. + + For more details see Documentation/kdump/kdump.txt + config XEN_DOM0 def_bool y depends on XEN diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 7700c0c..c13d3eb 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -48,6 +48,7 @@ arm64-obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o arm64-obj-$(CONFIG_HIBERNATION) += hibernate.o hibernate-asm.o arm64-obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o \ cpu-reset.o +arm64-obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-y += $(arm64-obj-y) vdso/ obj-m += $(arm64-obj-m) diff --git a/arch/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c new file mode 100644 index 0000000..2dc54d1 --- /dev/null +++ b/arch/arm64/kernel/crash_dump.c @@ -0,0 +1,71 @@ +/* + * Routines for doing kexec-based kdump + * + * Copyright (C) 2014 Linaro Limited + * Author: AKASHI Takahiro + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include + +/** + * copy_oldmem_page() - copy one page from old kernel memory + * @pfn: page frame number to be copied + * @buf: buffer where the copied page is placed + * @csize: number of bytes to copy + * @offset: offset in bytes into the page + * @userbuf: if set, @buf is in a user address space + * + * This function copies one page from old kernel memory into buffer pointed by + * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes + * copied or negative error in case of failure. + */ +ssize_t copy_oldmem_page(unsigned long pfn, char *buf, + size_t csize, unsigned long offset, + int userbuf) +{ + void *vaddr; + + if (!csize) + return 0; + + vaddr = ioremap_cache(__pfn_to_phys(pfn), PAGE_SIZE); + if (!vaddr) + return -ENOMEM; + + if (userbuf) { + if (copy_to_user(buf, vaddr + offset, csize)) { + iounmap(vaddr); + return -EFAULT; + } + } else { + memcpy(buf, vaddr + offset, csize); + } + + iounmap(vaddr); + + return csize; +} + +/** + * elfcorehdr_read - read from ELF core header + * @buf: buffer where the data is placed + * @csize: number of bytes to read + * @ppos: address in the memory + * + * This function reads @count bytes from elf core header which exists + * on crash dump kernel's memory. + */ +ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos) +{ + memcpy(buf, phys_to_virt((phys_addr_t)*ppos), count); + return count; +} diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 22e7bcf..5f8f43c 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -136,6 +137,57 @@ static void __init reserve_crashkernel(void) } #endif /* CONFIG_KEXEC_CORE */ +#ifdef CONFIG_CRASH_DUMP +static int __init early_init_dt_scan_elfcorehdr(unsigned long node, + const char *uname, int depth, void *data) +{ + const __be32 *reg; + int len; + + if (depth != 1 || strcmp(uname, "chosen") != 0) + return 0; + + reg = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len); + if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells))) + return 1; + + elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, ®); + elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, ®); + + return 1; +} + +/* + * reserve_elfcorehdr() - reserves memory for elf core header + * + * This function reserves elf core header given in "elfcorehdr=" kernel + * command line parameter. This region contains all the information about + * primary kernel's core image and is used by a dump capture kernel to + * access the system memory on primary kernel. + */ +static void __init reserve_elfcorehdr(void) +{ + of_scan_flat_dt(early_init_dt_scan_elfcorehdr, NULL); + + if (!elfcorehdr_size) + return; + + if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) { + pr_warn("elfcorehdr is overlapped\n"); + return; + } + + memblock_reserve(elfcorehdr_addr, elfcorehdr_size); + + pr_info("Reserving %lldKB of memory at 0x%llx for elfcorehdr\n", + elfcorehdr_size >> 10, elfcorehdr_addr); +} +#else +static void __init reserve_elfcorehdr(void) +{ + ; +} +#endif /* CONFIG_CRASH_DUMP */ /* * Return the maximum physical address for ZONE_DMA (DMA_BIT_MASK(32)). It * currently assumes that for memory starting above 4G, 32-bit devices will @@ -391,6 +443,8 @@ void __init arm64_memblock_init(void) reserve_crashkernel(); + reserve_elfcorehdr(); + early_init_fdt_scan_reserved_mem(); /* 4GB maximum for 32-bit only capable devices */