From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DBB3E15A7 for ; Mon, 5 Sep 2022 02:14:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8288CC433C1 for ; Mon, 5 Sep 2022 02:14:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662344067; bh=raV8JoAT9OfnN7e10fjZGnNq2y+7qJLcoQcWRFtyncM=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=gONtZ9lnxTKshm/Ky+E6jeTQJcI4kBgOXUAUmPmr7VnrJV/YTCI+kJiXNE1aIWUDU 0a7AXbwR3bA729ZZDN0mn9wnDkcf6cCl8SDF8Xj66lDynqkJoBG0igNUf3a9n5bKPr TgbU7bvSZEvxPxYSgTITO2PdDGTwhiU4wogmci95dVLwfKSLFfTbXUh89hv1wzuwNT Y3I4idcLOV2iBXHZBO43T8QQworSrNrn2FW93CIwOFjWL1ISASFS5a2m5yrqTNaenk 4MtY19nfl0yZmWnzFwOq4it6DG8AfoJKSSx2GztujaPkeZ6VnQHQ/AV7dHpQWXs7Wa EiLV48G3CgxOw== Received: by mail-vs1-f47.google.com with SMTP id d126so7532246vsd.13 for ; Sun, 04 Sep 2022 19:14:27 -0700 (PDT) X-Gm-Message-State: ACgBeo0bINx9LexcHbULJha0ZpKZqHg2buOSzLlaFsW0sJiQgdL1j3ut w1XHvQLVs7A26phgYhrMQRUjEZM1874Pncg77DI= X-Google-Smtp-Source: AA6agR72SQ/0ioLSyZj+zawzOvIcTULr4BadOXxAT6xu53Xmsuh+LF6OJOO9bARlUj0oJB8ofEyxxemLNOi8Cr4uSVo= X-Received: by 2002:a67:df81:0:b0:390:21a3:823a with SMTP id x1-20020a67df81000000b0039021a3823amr13311736vsk.70.1662344066307; Sun, 04 Sep 2022 19:14:26 -0700 (PDT) Precedence: bulk X-Mailing-List: loongarch@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <1661747823-23745-1-git-send-email-tangyouling@loongson.cn> <1661747823-23745-3-git-send-email-tangyouling@loongson.cn> In-Reply-To: From: Huacai Chen Date: Mon, 5 Sep 2022 10:14:15 +0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 2/3] LoongArch: Add kdump support To: Youling Tang Cc: Baoquan He , Eric Biederman , WANG Xuerui , Vivek Goyal , Dave Young , Guo Ren , Jiaxun Yang , kexec@lists.infradead.org, loongarch@lists.linux.dev, LKML Content-Type: text/plain; charset="UTF-8" On Mon, Sep 5, 2022 at 10:04 AM Youling Tang wrote: > > Hi, Huacai > > On 09/05/2022 09:38 AM, Huacai Chen wrote: > > Hi, Youling, > > > > On Mon, Sep 5, 2022 at 8:54 AM Youling Tang wrote: > >> > >> Hi, Huacai > >> > >> On 09/04/2022 08:21 PM, Huacai Chen wrote: > >>> Hi, Youling, > >>> > >>> I think crash.c can be merged into crash_dump.c > >> > >> Most architectures only implement copy_oldmem_page() in crash_dump.c, > >> I'm not sure if merging crash.c into crash_dump.c will break its > >> consistency? > >> > >> Thanks, > >> Youling > > Yes, you are right, crash.c cannot be merged into crash_dump.c, but it > > can be merged into machine_kexec.c, as arm64 and riscv do. > > For arm64, machine_crash_shutdown() is placed in machine_kexec.c, and > crash_smp_send_stop is placed in smp.c. If crash.c needs to be merged > into machine_kexec.c, should crash_shutdown_secondary and > crash_smp_send_stop be placed in smp.c? I don't want to touch smp.c, all merged into machine_kexec.c seems reasonable. Huacai > > Youling. > > > > Huacai > >> > >>> > >>> Huacai > >>> > >>> On Mon, Aug 29, 2022 at 12:37 PM Youling Tang wrote: > >>>> > >>>> This patch adds support for kdump, the kernel will reserve a region > >>>> for the crash kernel and jump there on panic. > >>>> > >>>> 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 fdt_reserve_elfcorehdr() at boot time. > >>>> > >>>> At the same time, it will also limit the crash kdump kernel to the > >>>> crashkernel area via a new device-tree property, "linux, usable-memory-range", > >>>> so as not to destroy the original kernel dump data. > >>>> > >>>> On crash dump kernel, /proc/vmcore will access the primary kernel's memory > >>>> with copy_oldmem_page(). > >>>> > >>>> I tested this on LoongArch 3A5000 machine and works as expected (Suggest > >>>> crashkernel parameter is "crashkernel=512M@2320M"), you may test it by > >>>> triggering a crash through /proc/sysrq_trigger: > >>>> > >>>> $ sudo kexec -p /boot/vmlinux-kdump --reuse-cmdline --append="nr_cpus=1" > >>>> # echo c > /proc/sysrq_trigger > >>>> > >>>> Signed-off-by: Youling Tang > >>>> --- > >>>> arch/loongarch/Kconfig | 22 ++++++ > >>>> arch/loongarch/Makefile | 4 + > >>>> arch/loongarch/kernel/Makefile | 3 +- > >>>> arch/loongarch/kernel/crash.c | 100 ++++++++++++++++++++++++ > >>>> arch/loongarch/kernel/crash_dump.c | 19 +++++ > >>>> arch/loongarch/kernel/machine_kexec.c | 12 ++- > >>>> arch/loongarch/kernel/mem.c | 6 ++ > >>>> arch/loongarch/kernel/relocate_kernel.S | 6 ++ > >>>> arch/loongarch/kernel/setup.c | 49 ++++++++++++ > >>>> arch/loongarch/kernel/traps.c | 4 + > >>>> 10 files changed, 217 insertions(+), 8 deletions(-) > >>>> create mode 100644 arch/loongarch/kernel/crash.c > >>>> create mode 100644 arch/loongarch/kernel/crash_dump.c > >>>> > >>>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig > >>>> index 903c82fa958d..7c1b07a5b5bd 100644 > >>>> --- a/arch/loongarch/Kconfig > >>>> +++ b/arch/loongarch/Kconfig > >>>> @@ -420,6 +420,28 @@ 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 > >>>> + > >>>> +config PHYSICAL_START > >>>> + hex "Physical address where the kernel is loaded" > >>>> + default "0x9000000091000000" if 64BIT > >>>> + depends on CRASH_DUMP > >>>> + help > >>>> + This gives the XKPRANGE address where the kernel is loaded. > >>>> + If you plan to use kernel for capturing the crash dump change > >>>> + this value to start of the reserved region (the "X" value as > >>>> + specified in the "crashkernel=YM@XM" command line boot parameter > >>>> + passed to the panic-ed kernel). > >>>> + > >>>> config SECCOMP > >>>> bool "Enable seccomp to safely compute untrusted bytecode" > >>>> depends on PROC_FS > >>>> diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile > >>>> index 4bc47f47cfd8..7dabd580426d 100644 > >>>> --- a/arch/loongarch/Makefile > >>>> +++ b/arch/loongarch/Makefile > >>>> @@ -48,7 +48,11 @@ KBUILD_CFLAGS_MODULE += -fplt -Wa,-mla-global-with-abs,-mla-local-with-abs > >>>> cflags-y += -ffreestanding > >>>> cflags-y += $(call cc-option, -mno-check-zero-division) > >>>> > >>>> +ifdef CONFIG_PHYSICAL_START > >>>> +load-y = $(CONFIG_PHYSICAL_START) > >>>> +else > >>>> load-y = 0x9000000000200000 > >>>> +endif > >>>> bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y) > >>>> > >>>> drivers-$(CONFIG_PCI) += arch/loongarch/pci/ > >>>> diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile > >>>> index 20b64ac3f128..df5aea129364 100644 > >>>> --- a/arch/loongarch/kernel/Makefile > >>>> +++ b/arch/loongarch/kernel/Makefile > >>>> @@ -17,7 +17,8 @@ obj-$(CONFIG_CPU_HAS_FPU) += fpu.o > >>>> obj-$(CONFIG_MODULES) += module.o module-sections.o > >>>> obj-$(CONFIG_STACKTRACE) += stacktrace.o > >>>> > >>>> -obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o > >>>> +obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o crash.o > >>>> +obj-$(CONFIG_CRASH_DUMP) += crash_dump.o > >>>> > >>>> obj-$(CONFIG_PROC_FS) += proc.o > >>>> > >>>> diff --git a/arch/loongarch/kernel/crash.c b/arch/loongarch/kernel/crash.c > >>>> new file mode 100644 > >>>> index 000000000000..b4f249ec6301 > >>>> --- /dev/null > >>>> +++ b/arch/loongarch/kernel/crash.c > >>>> @@ -0,0 +1,100 @@ > >>>> +// SPDX-License-Identifier: GPL-2.0 > >>>> +/* > >>>> + * Copyright (C) 2022 Loongson Technology Corporation Limited > >>>> + * > >>>> + * Derived from MIPS > >>>> + */ > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> + > >>>> +static cpumask_t cpus_in_crash = CPU_MASK_NONE; > >>>> + > >>>> +#ifdef CONFIG_SMP > >>>> +static void crash_shutdown_secondary(void *passed_regs) > >>>> +{ > >>>> + struct pt_regs *regs = passed_regs; > >>>> + int cpu = smp_processor_id(); > >>>> + > >>>> + /* > >>>> + * If we are passed registers, use those. Otherwise get the > >>>> + * regs from the last interrupt, which should be correct, as > >>>> + * we are in an interrupt. But if the regs are not there, > >>>> + * pull them from the top of the stack. They are probably > >>>> + * wrong, but we need something to keep from crashing again. > >>>> + */ > >>>> + if (!regs) > >>>> + regs = get_irq_regs(); > >>>> + if (!regs) > >>>> + regs = task_pt_regs(current); > >>>> + > >>>> + local_irq_disable(); > >>>> + if (!cpumask_test_cpu(cpu, &cpus_in_crash)) > >>>> + crash_save_cpu(regs, cpu); > >>>> + cpumask_set_cpu(cpu, &cpus_in_crash); > >>>> + > >>>> + while (!atomic_read(&kexec_ready_to_reboot)) > >>>> + cpu_relax(); > >>>> + > >>>> + kexec_reboot(); > >>>> +} > >>>> + > >>>> +/* Override the weak function in kernel/panic.c */ > >>>> +void crash_smp_send_stop(void) > >>>> +{ > >>>> + static int cpus_stopped; > >>>> + unsigned long timeout; > >>>> + unsigned int ncpus; > >>>> + > >>>> + /* > >>>> + * This function can be called twice in panic path, but obviously > >>>> + * we execute this only once. > >>>> + */ > >>>> + if (cpus_stopped) > >>>> + return; > >>>> + > >>>> + cpus_stopped = 1; > >>>> + > >>>> + /* Excluding the panic cpu */ > >>>> + ncpus = num_online_cpus() - 1; > >>>> + > >>>> + smp_call_function(crash_shutdown_secondary, NULL, 0); > >>>> + smp_wmb(); > >>>> + > >>>> + /* > >>>> + * The crash CPU sends an IPI and wait for other CPUs to > >>>> + * respond. Delay of at least 10 seconds. > >>>> + */ > >>>> + pr_emerg("Sending IPI to other cpus...\n"); > >>>> + timeout = USEC_PER_SEC * 10; > >>>> + while ((cpumask_weight(&cpus_in_crash) < ncpus) && timeout--) { > >>>> + cpu_relax(); > >>>> + udelay(1); > >>>> + } > >>>> +} > >>>> + > >>>> +#endif > >>>> + > >>>> +void machine_crash_shutdown(struct pt_regs *regs) > >>>> +{ > >>>> + int crashing_cpu; > >>>> + > >>>> + local_irq_disable(); > >>>> + > >>>> + crashing_cpu = smp_processor_id(); > >>>> + crash_save_cpu(regs, crashing_cpu); > >>>> + > >>>> + /* shutdown non-crashing cpus */ > >>>> + crash_smp_send_stop(); > >>>> + cpumask_set_cpu(crashing_cpu, &cpus_in_crash); > >>>> + > >>>> + pr_info("Starting crashdump kernel...\n"); > >>>> +} > >>>> diff --git a/arch/loongarch/kernel/crash_dump.c b/arch/loongarch/kernel/crash_dump.c > >>>> new file mode 100644 > >>>> index 000000000000..13e5d2f7870d > >>>> --- /dev/null > >>>> +++ b/arch/loongarch/kernel/crash_dump.c > >>>> @@ -0,0 +1,19 @@ > >>>> +// SPDX-License-Identifier: GPL-2.0 > >>>> +#include > >>>> +#include > >>>> +#include > >>>> + > >>>> +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, > >>>> + size_t csize, unsigned long offset) > >>>> +{ > >>>> + void *vaddr; > >>>> + > >>>> + if (!csize) > >>>> + return 0; > >>>> + > >>>> + vaddr = kmap_local_pfn(pfn); > >>>> + csize = copy_to_iter(vaddr + offset, csize, iter); > >>>> + kunmap_local(vaddr); > >>>> + > >>>> + return csize; > >>>> +} > >>>> diff --git a/arch/loongarch/kernel/machine_kexec.c b/arch/loongarch/kernel/machine_kexec.c > >>>> index 4ffcd4cd9c8c..f793a3ff09a3 100644 > >>>> --- a/arch/loongarch/kernel/machine_kexec.c > >>>> +++ b/arch/loongarch/kernel/machine_kexec.c > >>>> @@ -69,7 +69,7 @@ int machine_kexec_prepare(struct kimage *kimage) > >>>> continue; > >>>> } > >>>> > >>>> - /* kexec need a safe page to save reboot_code_buffer */ > >>>> + /* kexec/kdump need a safe page to save reboot_code_buffer */ > >>>> kimage->control_code_page = virt_to_page((void *)KEXEC_CTRL_CODE); > >>>> > >>>> reboot_code_buffer = > >>>> @@ -113,10 +113,6 @@ static void kexec_shutdown_secondary(void *) > >>>> > >>>> kexec_reboot(); > >>>> } > >>>> - > >>>> -void machine_crash_shutdown(struct pt_regs *regs) > >>>> -{ > >>>> -} > >>>> #endif > >>>> > >>>> void machine_shutdown(void) > >>>> @@ -135,7 +131,8 @@ void machine_kexec(struct kimage *image) > >>>> > >>>> jump_addr = (unsigned long)phys_to_virt(image->start); > >>>> > >>>> - first_ind_entry = (unsigned long)phys_to_virt(image->head & PAGE_MASK); > >>>> + if (image->type == KEXEC_TYPE_DEFAULT) > >>>> + first_ind_entry = (unsigned long)phys_to_virt(image->head & PAGE_MASK); > >>>> > >>>> /* > >>>> * The generic kexec code builds a page list with physical > >>>> @@ -167,7 +164,8 @@ void machine_kexec(struct kimage *image) > >>>> > >>>> /* > >>>> * We know we were online, and there will be no incoming IPIs at > >>>> - * this point. > >>>> + * this point. Mark online again before rebooting so that the crash > >>>> + * analysis tool will see us correctly. > >>>> */ > >>>> set_cpu_online(smp_processor_id(), true); > >>>> > >>>> diff --git a/arch/loongarch/kernel/mem.c b/arch/loongarch/kernel/mem.c > >>>> index 7423361b0ebc..c6def6ff81c8 100644 > >>>> --- a/arch/loongarch/kernel/mem.c > >>>> +++ b/arch/loongarch/kernel/mem.c > >>>> @@ -5,6 +5,7 @@ > >>>> #include > >>>> #include > >>>> #include > >>>> +#include > >>>> > >>>> #include > >>>> #include > >>>> @@ -61,4 +62,9 @@ void __init memblock_init(void) > >>>> > >>>> /* Reserve the initrd */ > >>>> reserve_initrd_mem(); > >>>> + > >>>> + /* Mainly reserved memory for the elf core head */ > >>>> + early_init_fdt_scan_reserved_mem(); > >>>> + /* Parse linux,usable-memory-range is for crash dump kernel */ > >>>> + early_init_dt_check_for_usable_mem_range(); > >>>> } > >>>> diff --git a/arch/loongarch/kernel/relocate_kernel.S b/arch/loongarch/kernel/relocate_kernel.S > >>>> index d1f242f74ea8..4ee5ac4ac2d7 100644 > >>>> --- a/arch/loongarch/kernel/relocate_kernel.S > >>>> +++ b/arch/loongarch/kernel/relocate_kernel.S > >>>> @@ -28,6 +28,12 @@ SYM_CODE_START(relocate_new_kernel) > >>>> move s2, a2 > >>>> move s3, a3 > >>>> > >>>> + /* > >>>> + * In case of a kdump/crash kernel, the indirection page is not > >>>> + * populated as the kernel is directly copied to a reserved location > >>>> + */ > >>>> + beqz s2, done > >>>> + > >>>> process_entry: > >>>> PTR_L s4, s2, 0 > >>>> PTR_ADDI s2, s2, SZREG > >>>> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c > >>>> index f938aae3e92c..ea34b77e402f 100644 > >>>> --- a/arch/loongarch/kernel/setup.c > >>>> +++ b/arch/loongarch/kernel/setup.c > >>>> @@ -19,6 +19,8 @@ > >>>> #include > >>>> #include > >>>> #include > >>>> +#include > >>>> +#include > >>>> #include > >>>> #include > >>>> #include > >>>> @@ -186,6 +188,50 @@ static int __init early_parse_mem(char *p) > >>>> } > >>>> early_param("mem", early_parse_mem); > >>>> > >>>> +static void __init loongarch_parse_crashkernel(void) > >>>> +{ > >>>> +#ifdef CONFIG_KEXEC > >>>> + unsigned long long start; > >>>> + unsigned long long total_mem; > >>>> + unsigned long long crash_size, crash_base; > >>>> + int ret; > >>>> + > >>>> + total_mem = memblock_phys_mem_size(); > >>>> + ret = parse_crashkernel(boot_command_line, total_mem, > >>>> + &crash_size, &crash_base); > >>>> + if (ret != 0 || crash_size <= 0) > >>>> + return; > >>>> + > >>>> + > >>>> + start = memblock_phys_alloc_range(crash_size, 1, crash_base, > >>>> + crash_base + crash_size); > >>>> + if (start != crash_base) { > >>>> + pr_warn("Invalid memory region reserved for crash kernel\n"); > >>>> + return; > >>>> + } > >>>> + > >>>> + crashk_res.start = crash_base; > >>>> + crashk_res.end = crash_base + crash_size - 1; > >>>> +#endif > >>>> +} > >>>> + > >>>> +static void __init request_crashkernel(struct resource *res) > >>>> +{ > >>>> +#ifdef CONFIG_KEXEC > >>>> + int ret; > >>>> + > >>>> + if (crashk_res.start == crashk_res.end) > >>>> + return; > >>>> + > >>>> + ret = request_resource(res, &crashk_res); > >>>> + if (!ret) > >>>> + pr_info("Reserving %ldMB of memory at %ldMB for crashkernel\n", > >>>> + (unsigned long)((crashk_res.end - > >>>> + crashk_res.start + 1) >> 20), > >>>> + (unsigned long)(crashk_res.start >> 20)); > >>>> +#endif > >>>> +} > >>>> + > >>>> void __init platform_init(void) > >>>> { > >>>> efi_init(); > >>>> @@ -229,6 +275,8 @@ static void __init arch_mem_init(char **cmdline_p) > >>>> > >>>> check_kernel_sections_mem(); > >>>> > >>>> + loongarch_parse_crashkernel(); > >>>> + > >>>> /* > >>>> * In order to reduce the possibility of kernel panic when failed to > >>>> * get IO TLB memory under CONFIG_SWIOTLB, it is better to allocate > >>>> @@ -290,6 +338,7 @@ static void __init resource_init(void) > >>>> request_resource(res, &code_resource); > >>>> request_resource(res, &data_resource); > >>>> request_resource(res, &bss_resource); > >>>> + request_crashkernel(res); > >>>> } > >>>> } > >>>> > >>>> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c > >>>> index aa1c95aaf595..0e610872f3f4 100644 > >>>> --- a/arch/loongarch/kernel/traps.c > >>>> +++ b/arch/loongarch/kernel/traps.c > >>>> @@ -10,6 +10,7 @@ > >>>> #include > >>>> #include > >>>> #include > >>>> +#include > >>>> #include > >>>> #include > >>>> #include > >>>> @@ -246,6 +247,9 @@ void __noreturn die(const char *str, struct pt_regs *regs) > >>>> > >>>> oops_exit(); > >>>> > >>>> + if (regs && kexec_should_crash(current)) > >>>> + crash_kexec(regs); > >>>> + > >>>> if (in_interrupt()) > >>>> panic("Fatal exception in interrupt"); > >>>> > >>>> -- > >>>> 2.36.0 > >>>> > >> > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 60A16ECAAD5 for ; Mon, 5 Sep 2022 02:50:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; 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Sun, 04 Sep 2022 19:14:26 -0700 (PDT) MIME-Version: 1.0 References: <1661747823-23745-1-git-send-email-tangyouling@loongson.cn> <1661747823-23745-3-git-send-email-tangyouling@loongson.cn> In-Reply-To: From: Huacai Chen Date: Mon, 5 Sep 2022 10:14:15 +0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 2/3] LoongArch: Add kdump support To: Youling Tang Cc: Baoquan He , Eric Biederman , WANG Xuerui , Vivek Goyal , Dave Young , Guo Ren , Jiaxun Yang , kexec@lists.infradead.org, loongarch@lists.linux.dev, LKML X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220904_191434_672329_0595AB86 X-CRM114-Status: GOOD ( 54.24 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On Mon, Sep 5, 2022 at 10:04 AM Youling Tang wrote: > > Hi, Huacai > > On 09/05/2022 09:38 AM, Huacai Chen wrote: > > Hi, Youling, > > > > On Mon, Sep 5, 2022 at 8:54 AM Youling Tang wrote: > >> > >> Hi, Huacai > >> > >> On 09/04/2022 08:21 PM, Huacai Chen wrote: > >>> Hi, Youling, > >>> > >>> I think crash.c can be merged into crash_dump.c > >> > >> Most architectures only implement copy_oldmem_page() in crash_dump.c, > >> I'm not sure if merging crash.c into crash_dump.c will break its > >> consistency? > >> > >> Thanks, > >> Youling > > Yes, you are right, crash.c cannot be merged into crash_dump.c, but it > > can be merged into machine_kexec.c, as arm64 and riscv do. > > For arm64, machine_crash_shutdown() is placed in machine_kexec.c, and > crash_smp_send_stop is placed in smp.c. If crash.c needs to be merged > into machine_kexec.c, should crash_shutdown_secondary and > crash_smp_send_stop be placed in smp.c? I don't want to touch smp.c, all merged into machine_kexec.c seems reasonable. Huacai > > Youling. > > > > Huacai > >> > >>> > >>> Huacai > >>> > >>> On Mon, Aug 29, 2022 at 12:37 PM Youling Tang wrote: > >>>> > >>>> This patch adds support for kdump, the kernel will reserve a region > >>>> for the crash kernel and jump there on panic. > >>>> > >>>> 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 fdt_reserve_elfcorehdr() at boot time. > >>>> > >>>> At the same time, it will also limit the crash kdump kernel to the > >>>> crashkernel area via a new device-tree property, "linux, usable-memory-range", > >>>> so as not to destroy the original kernel dump data. > >>>> > >>>> On crash dump kernel, /proc/vmcore will access the primary kernel's memory > >>>> with copy_oldmem_page(). > >>>> > >>>> I tested this on LoongArch 3A5000 machine and works as expected (Suggest > >>>> crashkernel parameter is "crashkernel=512M@2320M"), you may test it by > >>>> triggering a crash through /proc/sysrq_trigger: > >>>> > >>>> $ sudo kexec -p /boot/vmlinux-kdump --reuse-cmdline --append="nr_cpus=1" > >>>> # echo c > /proc/sysrq_trigger > >>>> > >>>> Signed-off-by: Youling Tang > >>>> --- > >>>> arch/loongarch/Kconfig | 22 ++++++ > >>>> arch/loongarch/Makefile | 4 + > >>>> arch/loongarch/kernel/Makefile | 3 +- > >>>> arch/loongarch/kernel/crash.c | 100 ++++++++++++++++++++++++ > >>>> arch/loongarch/kernel/crash_dump.c | 19 +++++ > >>>> arch/loongarch/kernel/machine_kexec.c | 12 ++- > >>>> arch/loongarch/kernel/mem.c | 6 ++ > >>>> arch/loongarch/kernel/relocate_kernel.S | 6 ++ > >>>> arch/loongarch/kernel/setup.c | 49 ++++++++++++ > >>>> arch/loongarch/kernel/traps.c | 4 + > >>>> 10 files changed, 217 insertions(+), 8 deletions(-) > >>>> create mode 100644 arch/loongarch/kernel/crash.c > >>>> create mode 100644 arch/loongarch/kernel/crash_dump.c > >>>> > >>>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig > >>>> index 903c82fa958d..7c1b07a5b5bd 100644 > >>>> --- a/arch/loongarch/Kconfig > >>>> +++ b/arch/loongarch/Kconfig > >>>> @@ -420,6 +420,28 @@ 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 > >>>> + > >>>> +config PHYSICAL_START > >>>> + hex "Physical address where the kernel is loaded" > >>>> + default "0x9000000091000000" if 64BIT > >>>> + depends on CRASH_DUMP > >>>> + help > >>>> + This gives the XKPRANGE address where the kernel is loaded. > >>>> + If you plan to use kernel for capturing the crash dump change > >>>> + this value to start of the reserved region (the "X" value as > >>>> + specified in the "crashkernel=YM@XM" command line boot parameter > >>>> + passed to the panic-ed kernel). > >>>> + > >>>> config SECCOMP > >>>> bool "Enable seccomp to safely compute untrusted bytecode" > >>>> depends on PROC_FS > >>>> diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile > >>>> index 4bc47f47cfd8..7dabd580426d 100644 > >>>> --- a/arch/loongarch/Makefile > >>>> +++ b/arch/loongarch/Makefile > >>>> @@ -48,7 +48,11 @@ KBUILD_CFLAGS_MODULE += -fplt -Wa,-mla-global-with-abs,-mla-local-with-abs > >>>> cflags-y += -ffreestanding > >>>> cflags-y += $(call cc-option, -mno-check-zero-division) > >>>> > >>>> +ifdef CONFIG_PHYSICAL_START > >>>> +load-y = $(CONFIG_PHYSICAL_START) > >>>> +else > >>>> load-y = 0x9000000000200000 > >>>> +endif > >>>> bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y) > >>>> > >>>> drivers-$(CONFIG_PCI) += arch/loongarch/pci/ > >>>> diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile > >>>> index 20b64ac3f128..df5aea129364 100644 > >>>> --- a/arch/loongarch/kernel/Makefile > >>>> +++ b/arch/loongarch/kernel/Makefile > >>>> @@ -17,7 +17,8 @@ obj-$(CONFIG_CPU_HAS_FPU) += fpu.o > >>>> obj-$(CONFIG_MODULES) += module.o module-sections.o > >>>> obj-$(CONFIG_STACKTRACE) += stacktrace.o > >>>> > >>>> -obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o > >>>> +obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o crash.o > >>>> +obj-$(CONFIG_CRASH_DUMP) += crash_dump.o > >>>> > >>>> obj-$(CONFIG_PROC_FS) += proc.o > >>>> > >>>> diff --git a/arch/loongarch/kernel/crash.c b/arch/loongarch/kernel/crash.c > >>>> new file mode 100644 > >>>> index 000000000000..b4f249ec6301 > >>>> --- /dev/null > >>>> +++ b/arch/loongarch/kernel/crash.c > >>>> @@ -0,0 +1,100 @@ > >>>> +// SPDX-License-Identifier: GPL-2.0 > >>>> +/* > >>>> + * Copyright (C) 2022 Loongson Technology Corporation Limited > >>>> + * > >>>> + * Derived from MIPS > >>>> + */ > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> +#include > >>>> + > >>>> +static cpumask_t cpus_in_crash = CPU_MASK_NONE; > >>>> + > >>>> +#ifdef CONFIG_SMP > >>>> +static void crash_shutdown_secondary(void *passed_regs) > >>>> +{ > >>>> + struct pt_regs *regs = passed_regs; > >>>> + int cpu = smp_processor_id(); > >>>> + > >>>> + /* > >>>> + * If we are passed registers, use those. Otherwise get the > >>>> + * regs from the last interrupt, which should be correct, as > >>>> + * we are in an interrupt. But if the regs are not there, > >>>> + * pull them from the top of the stack. They are probably > >>>> + * wrong, but we need something to keep from crashing again. > >>>> + */ > >>>> + if (!regs) > >>>> + regs = get_irq_regs(); > >>>> + if (!regs) > >>>> + regs = task_pt_regs(current); > >>>> + > >>>> + local_irq_disable(); > >>>> + if (!cpumask_test_cpu(cpu, &cpus_in_crash)) > >>>> + crash_save_cpu(regs, cpu); > >>>> + cpumask_set_cpu(cpu, &cpus_in_crash); > >>>> + > >>>> + while (!atomic_read(&kexec_ready_to_reboot)) > >>>> + cpu_relax(); > >>>> + > >>>> + kexec_reboot(); > >>>> +} > >>>> + > >>>> +/* Override the weak function in kernel/panic.c */ > >>>> +void crash_smp_send_stop(void) > >>>> +{ > >>>> + static int cpus_stopped; > >>>> + unsigned long timeout; > >>>> + unsigned int ncpus; > >>>> + > >>>> + /* > >>>> + * This function can be called twice in panic path, but obviously > >>>> + * we execute this only once. > >>>> + */ > >>>> + if (cpus_stopped) > >>>> + return; > >>>> + > >>>> + cpus_stopped = 1; > >>>> + > >>>> + /* Excluding the panic cpu */ > >>>> + ncpus = num_online_cpus() - 1; > >>>> + > >>>> + smp_call_function(crash_shutdown_secondary, NULL, 0); > >>>> + smp_wmb(); > >>>> + > >>>> + /* > >>>> + * The crash CPU sends an IPI and wait for other CPUs to > >>>> + * respond. Delay of at least 10 seconds. > >>>> + */ > >>>> + pr_emerg("Sending IPI to other cpus...\n"); > >>>> + timeout = USEC_PER_SEC * 10; > >>>> + while ((cpumask_weight(&cpus_in_crash) < ncpus) && timeout--) { > >>>> + cpu_relax(); > >>>> + udelay(1); > >>>> + } > >>>> +} > >>>> + > >>>> +#endif > >>>> + > >>>> +void machine_crash_shutdown(struct pt_regs *regs) > >>>> +{ > >>>> + int crashing_cpu; > >>>> + > >>>> + local_irq_disable(); > >>>> + > >>>> + crashing_cpu = smp_processor_id(); > >>>> + crash_save_cpu(regs, crashing_cpu); > >>>> + > >>>> + /* shutdown non-crashing cpus */ > >>>> + crash_smp_send_stop(); > >>>> + cpumask_set_cpu(crashing_cpu, &cpus_in_crash); > >>>> + > >>>> + pr_info("Starting crashdump kernel...\n"); > >>>> +} > >>>> diff --git a/arch/loongarch/kernel/crash_dump.c b/arch/loongarch/kernel/crash_dump.c > >>>> new file mode 100644 > >>>> index 000000000000..13e5d2f7870d > >>>> --- /dev/null > >>>> +++ b/arch/loongarch/kernel/crash_dump.c > >>>> @@ -0,0 +1,19 @@ > >>>> +// SPDX-License-Identifier: GPL-2.0 > >>>> +#include > >>>> +#include > >>>> +#include > >>>> + > >>>> +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, > >>>> + size_t csize, unsigned long offset) > >>>> +{ > >>>> + void *vaddr; > >>>> + > >>>> + if (!csize) > >>>> + return 0; > >>>> + > >>>> + vaddr = kmap_local_pfn(pfn); > >>>> + csize = copy_to_iter(vaddr + offset, csize, iter); > >>>> + kunmap_local(vaddr); > >>>> + > >>>> + return csize; > >>>> +} > >>>> diff --git a/arch/loongarch/kernel/machine_kexec.c b/arch/loongarch/kernel/machine_kexec.c > >>>> index 4ffcd4cd9c8c..f793a3ff09a3 100644 > >>>> --- a/arch/loongarch/kernel/machine_kexec.c > >>>> +++ b/arch/loongarch/kernel/machine_kexec.c > >>>> @@ -69,7 +69,7 @@ int machine_kexec_prepare(struct kimage *kimage) > >>>> continue; > >>>> } > >>>> > >>>> - /* kexec need a safe page to save reboot_code_buffer */ > >>>> + /* kexec/kdump need a safe page to save reboot_code_buffer */ > >>>> kimage->control_code_page = virt_to_page((void *)KEXEC_CTRL_CODE); > >>>> > >>>> reboot_code_buffer = > >>>> @@ -113,10 +113,6 @@ static void kexec_shutdown_secondary(void *) > >>>> > >>>> kexec_reboot(); > >>>> } > >>>> - > >>>> -void machine_crash_shutdown(struct pt_regs *regs) > >>>> -{ > >>>> -} > >>>> #endif > >>>> > >>>> void machine_shutdown(void) > >>>> @@ -135,7 +131,8 @@ void machine_kexec(struct kimage *image) > >>>> > >>>> jump_addr = (unsigned long)phys_to_virt(image->start); > >>>> > >>>> - first_ind_entry = (unsigned long)phys_to_virt(image->head & PAGE_MASK); > >>>> + if (image->type == KEXEC_TYPE_DEFAULT) > >>>> + first_ind_entry = (unsigned long)phys_to_virt(image->head & PAGE_MASK); > >>>> > >>>> /* > >>>> * The generic kexec code builds a page list with physical > >>>> @@ -167,7 +164,8 @@ void machine_kexec(struct kimage *image) > >>>> > >>>> /* > >>>> * We know we were online, and there will be no incoming IPIs at > >>>> - * this point. > >>>> + * this point. Mark online again before rebooting so that the crash > >>>> + * analysis tool will see us correctly. > >>>> */ > >>>> set_cpu_online(smp_processor_id(), true); > >>>> > >>>> diff --git a/arch/loongarch/kernel/mem.c b/arch/loongarch/kernel/mem.c > >>>> index 7423361b0ebc..c6def6ff81c8 100644 > >>>> --- a/arch/loongarch/kernel/mem.c > >>>> +++ b/arch/loongarch/kernel/mem.c > >>>> @@ -5,6 +5,7 @@ > >>>> #include > >>>> #include > >>>> #include > >>>> +#include > >>>> > >>>> #include > >>>> #include > >>>> @@ -61,4 +62,9 @@ void __init memblock_init(void) > >>>> > >>>> /* Reserve the initrd */ > >>>> reserve_initrd_mem(); > >>>> + > >>>> + /* Mainly reserved memory for the elf core head */ > >>>> + early_init_fdt_scan_reserved_mem(); > >>>> + /* Parse linux,usable-memory-range is for crash dump kernel */ > >>>> + early_init_dt_check_for_usable_mem_range(); > >>>> } > >>>> diff --git a/arch/loongarch/kernel/relocate_kernel.S b/arch/loongarch/kernel/relocate_kernel.S > >>>> index d1f242f74ea8..4ee5ac4ac2d7 100644 > >>>> --- a/arch/loongarch/kernel/relocate_kernel.S > >>>> +++ b/arch/loongarch/kernel/relocate_kernel.S > >>>> @@ -28,6 +28,12 @@ SYM_CODE_START(relocate_new_kernel) > >>>> move s2, a2 > >>>> move s3, a3 > >>>> > >>>> + /* > >>>> + * In case of a kdump/crash kernel, the indirection page is not > >>>> + * populated as the kernel is directly copied to a reserved location > >>>> + */ > >>>> + beqz s2, done > >>>> + > >>>> process_entry: > >>>> PTR_L s4, s2, 0 > >>>> PTR_ADDI s2, s2, SZREG > >>>> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c > >>>> index f938aae3e92c..ea34b77e402f 100644 > >>>> --- a/arch/loongarch/kernel/setup.c > >>>> +++ b/arch/loongarch/kernel/setup.c > >>>> @@ -19,6 +19,8 @@ > >>>> #include > >>>> #include > >>>> #include > >>>> +#include > >>>> +#include > >>>> #include > >>>> #include > >>>> #include > >>>> @@ -186,6 +188,50 @@ static int __init early_parse_mem(char *p) > >>>> } > >>>> early_param("mem", early_parse_mem); > >>>> > >>>> +static void __init loongarch_parse_crashkernel(void) > >>>> +{ > >>>> +#ifdef CONFIG_KEXEC > >>>> + unsigned long long start; > >>>> + unsigned long long total_mem; > >>>> + unsigned long long crash_size, crash_base; > >>>> + int ret; > >>>> + > >>>> + total_mem = memblock_phys_mem_size(); > >>>> + ret = parse_crashkernel(boot_command_line, total_mem, > >>>> + &crash_size, &crash_base); > >>>> + if (ret != 0 || crash_size <= 0) > >>>> + return; > >>>> + > >>>> + > >>>> + start = memblock_phys_alloc_range(crash_size, 1, crash_base, > >>>> + crash_base + crash_size); > >>>> + if (start != crash_base) { > >>>> + pr_warn("Invalid memory region reserved for crash kernel\n"); > >>>> + return; > >>>> + } > >>>> + > >>>> + crashk_res.start = crash_base; > >>>> + crashk_res.end = crash_base + crash_size - 1; > >>>> +#endif > >>>> +} > >>>> + > >>>> +static void __init request_crashkernel(struct resource *res) > >>>> +{ > >>>> +#ifdef CONFIG_KEXEC > >>>> + int ret; > >>>> + > >>>> + if (crashk_res.start == crashk_res.end) > >>>> + return; > >>>> + > >>>> + ret = request_resource(res, &crashk_res); > >>>> + if (!ret) > >>>> + pr_info("Reserving %ldMB of memory at %ldMB for crashkernel\n", > >>>> + (unsigned long)((crashk_res.end - > >>>> + crashk_res.start + 1) >> 20), > >>>> + (unsigned long)(crashk_res.start >> 20)); > >>>> +#endif > >>>> +} > >>>> + > >>>> void __init platform_init(void) > >>>> { > >>>> efi_init(); > >>>> @@ -229,6 +275,8 @@ static void __init arch_mem_init(char **cmdline_p) > >>>> > >>>> check_kernel_sections_mem(); > >>>> > >>>> + loongarch_parse_crashkernel(); > >>>> + > >>>> /* > >>>> * In order to reduce the possibility of kernel panic when failed to > >>>> * get IO TLB memory under CONFIG_SWIOTLB, it is better to allocate > >>>> @@ -290,6 +338,7 @@ static void __init resource_init(void) > >>>> request_resource(res, &code_resource); > >>>> request_resource(res, &data_resource); > >>>> request_resource(res, &bss_resource); > >>>> + request_crashkernel(res); > >>>> } > >>>> } > >>>> > >>>> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c > >>>> index aa1c95aaf595..0e610872f3f4 100644 > >>>> --- a/arch/loongarch/kernel/traps.c > >>>> +++ b/arch/loongarch/kernel/traps.c > >>>> @@ -10,6 +10,7 @@ > >>>> #include > >>>> #include > >>>> #include > >>>> +#include > >>>> #include > >>>> #include > >>>> #include > >>>> @@ -246,6 +247,9 @@ void __noreturn die(const char *str, struct pt_regs *regs) > >>>> > >>>> oops_exit(); > >>>> > >>>> + if (regs && kexec_should_crash(current)) > >>>> + crash_kexec(regs); > >>>> + > >>>> if (in_interrupt()) > >>>> panic("Fatal exception in interrupt"); > >>>> > >>>> -- > >>>> 2.36.0 > >>>> > >> > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec