From patchwork Tue Feb 7 08:09:02 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: AKASHI Takahiro X-Patchwork-Id: 9559425 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 7037C60434 for ; Tue, 7 Feb 2017 08:29:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 624E020246 for ; Tue, 7 Feb 2017 08:29:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 56F3326E1A; Tue, 7 Feb 2017 08:29:51 +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=-1.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, T_DKIM_INVALID autolearn=no version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id D3B1620246 for ; Tue, 7 Feb 2017 08:29:50 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cb19m-0001N0-EW; Tue, 07 Feb 2017 08:29:46 +0000 Received: from merlin.infradead.org ([205.233.59.134]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cb172-0007nK-Uc for linux-arm-kernel@bombadil.infradead.org; Tue, 07 Feb 2017 08:26:57 +0000 Received: from mail-pg0-x22f.google.com ([2607:f8b0:400e:c05::22f]) by merlin.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cb0s5-0000I7-Az for linux-arm-kernel@lists.infradead.org; Tue, 07 Feb 2017 08:11:30 +0000 Received: by mail-pg0-x22f.google.com with SMTP id 204so36731581pge.0 for ; Tue, 07 Feb 2017 00:11:09 -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=c6Lv5rgTLLj5+PUc8q41BCSW1Wdm9uj6jGWlbOUASsc=; b=b/cH2fxBa2uQlUb36WdDTf7gRCR8o2QfhTJm6XDgvQLsSDb+FHfh/rbkBka/NsHIQJ KbDK07gFpEVDBdR3hG0aFTQMPsrS9jRz9kKDfW9hOkBdjCa75fC+tMDKNSarh79mCl9g GRhEAnnMgxtDtcWsBet1DYmFbtCtgh8R4dHgs= 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=c6Lv5rgTLLj5+PUc8q41BCSW1Wdm9uj6jGWlbOUASsc=; b=MqbWR0KZL0nqsBMSPj4u6eT8IuxwQt+qcKwDRFUtxO2iGuYMTBiiTpokdjwi4PyjrG sThJ/I1vq80SZhtk/XYyX1WpKxvRyGBfBgIAsXCorCCXtxtKgeVvSe12+jYAnSNFliT1 eJblCn7edXto19dzoqUdWdZOaW1WOM4bdHNUpzbvBv29A031flIZlFB2QZ65BMAQvvBW aZRyIJMKDakUo+1i8WAuKK2zm2O7F3F7ZOEcPcqpTD1xMyYHI5cCdGuUlO7NULtiq+Y4 jz0YDZ4WacC0LkQhVimvWZQ5d32qKz1MpAlhkqGbkvV430p857kB0rQLmqAEHz1zwU2F olRw== X-Gm-Message-State: AIkVDXKuXtDHWCGuNgKuAHn8Dj/0/G1Ep6BmOCBDeW4ssrfG+IUczldrwMvaq29vYlFU6YgQ X-Received: by 10.98.110.194 with SMTP id j185mr18579876pfc.157.1486454888216; Tue, 07 Feb 2017 00:08:08 -0800 (PST) Received: from linaro.org ([121.95.100.191]) by smtp.googlemail.com with ESMTPSA id k76sm8539648pfg.42.2017.02.07.00.08.07 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 07 Feb 2017 00:08:07 -0800 (PST) From: AKASHI Takahiro To: catalin.marinas@arm.com, will.deacon@arm.com Subject: [PATCH v32 10/13] arm64: kdump: provide /proc/vmcore file Date: Tue, 7 Feb 2017 17:09:02 +0900 Message-Id: <20170207080904.5974-8-takahiro.akashi@linaro.org> X-Mailer: git-send-email 2.11.1 In-Reply-To: <20170207080601.5816-1-takahiro.akashi@linaro.org> References: <20170207080601.5816-1-takahiro.akashi@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170207_031129_865441_60B7AEA0 X-CRM114-Status: GOOD ( 30.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 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 Arch-specific functions are added to allow for implementing a crash dump file interface, /proc/vmcore, which can be viewed as a ELF file. A user space tool, like kexec-tools, is responsible for allocating a separate region for the core's ELF header within crash kdump kernel memory and filling it in when executing kexec_load(). Then, its location will be advertised to crash dump kernel via a new device-tree property, "linux,elfcorehdr", and crash dump kernel preserves the region for later use with reserve_elfcorehdr() at boot time. On crash dump kernel, /proc/vmcore 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. Meanwhile, elfcorehdr_read() is simple as the region is always mapped. 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 | 53 +++++++++++++++++++++++++++++++ 4 files changed, 136 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..f46d57c31443 --- /dev/null +++ b/arch/arm64/kernel/crash_dump.c @@ -0,0 +1,71 @@ +/* + * Routines for doing kexec-based kdump + * + * Copyright (C) 2017 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 083e8fc9b771..a95f8edebf51 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -38,6 +38,7 @@ #include #include #include +#include #include #include @@ -139,6 +140,56 @@ 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 the memory occupied by an elf core header + * described in the device tree. 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 @@ -397,6 +448,8 @@ void __init arm64_memblock_init(void) reserve_crashkernel(); + reserve_elfcorehdr(); + dma_contiguous_reserve(arm64_dma_phys_limit); memblock_allow_resize();