From patchwork Wed Dec 28 04:36:03 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: AKASHI Takahiro X-Patchwork-Id: 9489971 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 C24A462AB0 for ; Wed, 28 Dec 2016 04:39:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 99F7620144 for ; Wed, 28 Dec 2016 04:39:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8E16F2094F; Wed, 28 Dec 2016 04:39:04 +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=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID 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 0274420144 for ; Wed, 28 Dec 2016 04:39:04 +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 1cM5zY-0006Z5-M4; Wed, 28 Dec 2016 04:37:32 +0000 Received: from mail-pg0-x233.google.com ([2607:f8b0:400e:c05::233]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1cM5yk-000605-NO for linux-arm-kernel@lists.infradead.org; Wed, 28 Dec 2016 04:36:48 +0000 Received: by mail-pg0-x233.google.com with SMTP id y62so99567177pgy.1 for ; Tue, 27 Dec 2016 20:36:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=JZDrj8iXb4GdCmGtm2YIOgsNapwShnd0wkpeE1qZrjA=; b=gdBUc+DfHeim0Flreu52H+wOqRJenQFxCE+tYbklJTIpwJzF9ZxBzgynoYMPVMDEO1 PndgchttAgCgCnwpC+JNzR/+H3ZBYylyY0YIANhHHRmE2PWiDVEfPGnA6DrwM99okfZl dJj88sSvqriMBWj33KYNBSrEqakBtXlyj8eBE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=JZDrj8iXb4GdCmGtm2YIOgsNapwShnd0wkpeE1qZrjA=; b=KJB1kvdMgflvOaujAoK2gaecYHjN1o9SjexggALSLkETkrJZmiI3wxDwP+/4f96onq ASv69ib/sCNAB9dWOuppsUZBefkPXsK3v9Hk8ONVIG1iEzuKZ4n71j76vg+e2Vs4Viam 0Qy/d4mhcgPIuqn3huCVNw93pJTf4OfbPd8Q2VFyfe0oZXACeixUC5PGryLZK2RYX/iK sTbRNONrCTrOoGrh6G7AryxDv25nivied0TrPDZMuy7FxxYu+doFFu/clhRccI1TFWgs +3C/pKyPYpiFhytD0ZRBgnPOaDI6C2oxc+zoO9q7E1sBSH89/MaQ74WQ4dMVMS/ef45V iXuw== X-Gm-Message-State: AIkVDXJN94dZfwVVmh/nye1qamxMbiimOUa2i/bGoU5bgF+N75x2QFh1NnDG0x1uHRpOWc3V X-Received: by 10.99.3.5 with SMTP id 5mr39546671pgd.150.1482899781388; Tue, 27 Dec 2016 20:36:21 -0800 (PST) Received: from linaro.org ([121.95.100.191]) by smtp.googlemail.com with ESMTPSA id c15sm92904748pfd.36.2016.12.27.20.36.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 27 Dec 2016 20:36:20 -0800 (PST) From: AKASHI Takahiro To: catalin.marinas@arm.com, will.deacon@arm.com Subject: [PATCH v29 6/9] arm64: kdump: provide /proc/vmcore file Date: Wed, 28 Dec 2016 13:36:03 +0900 Message-Id: <20161228043605.27470-5-takahiro.akashi@linaro.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20161228043347.27358-1-takahiro.akashi@linaro.org> References: <20161228043347.27358-1-takahiro.akashi@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161227_203643_022417_264B1872 X-CRM114-Status: GOOD ( 25.09 ) 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@arm.com, geoff@infradead.org, kexec@lists.infradead.org, AKASHI Takahiro , james.morse@arm.com, bauerman@linux.vnet.ibm.com, dyoung@redhat.com, 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 Add arch-specific functions to provide a dump file, /proc/vmcore. This file is in ELF format and its ELF header needs to be prepared by userspace tools, like kexec-tools, in adance. The primary kernel is responsible to allocate the region with reserve_elfcorehdr() at boot time and advertize its location to crash dump kernel via a new device-tree property, "linux,elfcorehdr". Then crash dump kernel will access the primary kernel's memory with copy_oldmem_page(), which feeds the data page-by-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 Reviewed-by: James Morse Acked-by: Catalin Marinas --- 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 111742126897..2bd6a1a062b9 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -693,6 +693,17 @@ 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 7d66bbaafc0c..6a7384eee08d 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -50,6 +50,7 @@ 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/ probes/ 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 000000000000..c3d5a21c081e --- /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 = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB); + if (!vaddr) + return -ENOMEM; + + if (userbuf) { + if (copy_to_user((char __user *)buf, vaddr + offset, csize)) { + memunmap(vaddr); + return -EFAULT; + } + } else { + memcpy(buf, vaddr + offset, csize); + } + + memunmap(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 1d62bf71b531..ef8adfde32e7 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -38,6 +38,7 @@ #include #include #include +#include #include #include @@ -183,6 +184,57 @@ 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 @@ -441,6 +493,8 @@ void __init arm64_memblock_init(void) reserve_crashkernel(); + reserve_elfcorehdr(); + dma_contiguous_reserve(arm64_dma_phys_limit); memblock_allow_resize();