[v4,5/5] RISC-V: Add crash kernel support

Message ID	20210419005539.22729-6-mick@ics.forth.gr (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=YGcN=JQ=lists.infradead.org=linux-riscv-bounces+linux-riscv=archiver.kernel.org@kernel.org> DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B511960C40 user: mick@ics.forth.gr at ics.forth.gr From: Nick Kossifidis <mick@ics.forth.gr> To: linux-riscv@lists.infradead.org, palmer@dabbelt.com Cc: paul.walmsley@sifive.com, linux-kernel@vger.kernel.org, Nick Kossifidis <mick@ics.forth.gr> Subject: [PATCH v4 5/5] RISC-V: Add crash kernel support Date: Mon, 19 Apr 2021 03:55:39 +0300 Message-Id: <20210419005539.22729-6-mick@ics.forth.gr> In-Reply-To: <20210419005539.22729-1-mick@ics.forth.gr> References: <20210419005539.22729-1-mick@ics.forth.gr> MIME-Version: 1.0 Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" <linux-riscv-bounces@lists.infradead.org> Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org
Series	RISC-V: Add kexec/kdump support \| expand [v4,0/5] RISC-V: Add kexec/kdump support [v4,1/5] RISC-V: Add EM_RISCV to kexec UAPI header [v4,2/5] RISC-V: Add kexec support [v4,3/5] RISC-V: Improve init_resources [v4,4/5] RISC-V: Add kdump support [v4,5/5] RISC-V: Add crash kernel support

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 10cc19be0..39aa18ef4 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -400,6 +400,16 @@ config KEXEC The name comes from the similarity to the exec system call. +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/admin-guide/kdump/kdump.rst endmenu diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 41a1469b2..d3081e4d9 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -60,6 +60,7 @@ endif obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_KEXEC) += kexec_relocate.o crash_save_regs.o machine_kexec.o +obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o diff --git a/arch/riscv/kernel/crash_dump.c b/arch/riscv/kernel/crash_dump.c new file mode 100644 index 000000000..86cc0ada5 --- /dev/null +++ b/arch/riscv/kernel/crash_dump.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This code comes from arch/arm64/kernel/crash_dump.c + * Created by: AKASHI Takahiro <takahiro.akashi@linaro.org> + * Copyright (C) 2017 Linaro Limited + */ + +#include <linux/crash_dump.h> +#include <linux/io.h> + +/** + * 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; +} diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 31866dce9..ff398a3d8 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -66,6 +66,9 @@ static struct resource code_res = { .name = "Kernel code", }; static struct resource data_res = { .name = "Kernel data", }; static struct resource rodata_res = { .name = "Kernel rodata", }; static struct resource bss_res = { .name = "Kernel bss", }; +#ifdef CONFIG_CRASH_DUMP +static struct resource elfcorehdr_res = { .name = "ELF Core hdr", }; +#endif static int __init add_resource(struct resource *parent, struct resource *res) @@ -169,6 +172,15 @@ static void __init init_resources(void) } #endif +#ifdef CONFIG_CRASH_DUMP + if (elfcorehdr_size > 0) { + elfcorehdr_res.start = elfcorehdr_addr; + elfcorehdr_res.end = elfcorehdr_addr + elfcorehdr_size - 1; + elfcorehdr_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + add_resource(&iomem_resource, &elfcorehdr_res); + } +#endif + for_each_reserved_mem_region(region) { res = &mem_res[res_idx--]; diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 8b2b85a57..9c048fccb 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -13,6 +13,7 @@ #include <linux/swap.h> #include <linux/sizes.h> #include <linux/of_fdt.h> +#include <linux/of_reserved_mem.h> #include <linux/libfdt.h> #include <linux/set_memory.h> #include <linux/dma-map-ops.h> @@ -605,6 +606,18 @@ static void __init reserve_crashkernel(void) int ret = 0; + /* + * Don't reserve a region for a crash kernel on a crash kernel + * since it doesn't make much sense and we have limited memory + * resources. + */ +#ifdef CONFIG_CRASH_DUMP + if (is_kdump_kernel()) { + pr_info("crashkernel: ignoring reservation request\n"); + return; + } +#endif + ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), &crash_size, &crash_base); if (ret || !crash_size) @@ -653,6 +666,26 @@ static void __init reserve_crashkernel(void) } #endif /* CONFIG_KEXEC_CORE */ +#ifdef CONFIG_CRASH_DUMP +/* + * We keep track of the ELF core header of the crashed + * kernel with a reserved-memory region with compatible + * string "linux,elfcorehdr". Here we register a callback + * to populate elfcorehdr_addr/size when this region is + * present. Note that this region will be marked as + * reserved once we call early_init_fdt_scan_reserved_mem() + * later on. + */ +static int elfcore_hdr_setup(struct reserved_mem *rmem) +{ + elfcorehdr_addr = rmem->base; + elfcorehdr_size = rmem->size; + return 0; +} + +RESERVEDMEM_OF_DECLARE(elfcorehdr, "linux,elfcorehdr", elfcore_hdr_setup); +#endif + void __init paging_init(void) { setup_vm_final();

[v4,5/5] RISC-V: Add crash kernel support

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