From nobody Tue Apr 7 12:23:22 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C6BFECAAD4 for ; Mon, 29 Aug 2022 04:37:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229683AbiH2Eh1 (ORCPT ); Mon, 29 Aug 2022 00:37:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229637AbiH2EhS (ORCPT ); Mon, 29 Aug 2022 00:37:18 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 471203ECFA for ; Sun, 28 Aug 2022 21:37:16 -0700 (PDT) Received: from bogon.localdomain (unknown [113.200.148.30]) by localhost.localdomain (Coremail) with SMTP id AQAAf8DxvmtvQgxjO6YLAA--.39821S4; Mon, 29 Aug 2022 12:37:07 +0800 (CST) From: Youling Tang To: Huacai Chen , Baoquan He , Eric Biederman Cc: WANG Xuerui , Vivek Goyal , Dave Young , Guo Ren , Jiaxun Yang , kexec@lists.infradead.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 2/3] LoongArch: Add kdump support Date: Mon, 29 Aug 2022 12:37:02 +0800 Message-Id: <1661747823-23745-3-git-send-email-tangyouling@loongson.cn> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1661747823-23745-1-git-send-email-tangyouling@loongson.cn> References: <1661747823-23745-1-git-send-email-tangyouling@loongson.cn> X-CM-TRANSID: AQAAf8DxvmtvQgxjO6YLAA--.39821S4 X-Coremail-Antispam: 1UD129KBjvAXoW3ur4kur15XryrAF17Xry3CFg_yoW8Gr1UGo WftF1xtw18GrW29rsYkF1qyFW5Gr1qkFsxZ39Ivw43WF9ay34jqry8KryYy347Jw4kWw4x W343WrWjy397Jr95n29KB7ZKAUJUUUU5529EdanIXcx71UUUUU7v73VFW2AGmfu7bjvjm3 AaLaJ3UjIYCTnIWjp_UUUO57k0a2IF6w4kM7kC6x804xWl14x267AKxVWrJVCq3wAFc2x0 x2IEx4CE42xK8VAvwI8IcIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87 I2jVAFwI0_Jryl82xGYIkIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY 1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20x vEc7CjxVAFwI0_Cr0_Gr1UM28EF7xvwVC2z280aVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2 jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4 CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r4j6F4UMcvj eVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxw CY02Avz4vE14v_Gryl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2Iq xVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r 1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY 6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67 AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuY vjxUyoqcDUUUU X-CM-SenderInfo: 5wdqw5prxox03j6o00pqjv00gofq/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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-rang= e", 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=3D512M@2320M"), you may test it by triggering a crash through /proc/sysrq_trigger: $ sudo kexec -p /boot/vmlinux-kdump --reuse-cmdline --append=3D"nr_cpus=3D= 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 =20 The name comes from the similarity to the exec system call. =20 +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=3DYM@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 +=3D -fplt -Wa,-mla-global-with-ab= s,-mla-local-with-abs cflags-y +=3D -ffreestanding cflags-y +=3D $(call cc-option, -mno-check-zero-division) =20 +ifdef CONFIG_PHYSICAL_START +load-y =3D $(CONFIG_PHYSICAL_START) +else load-y =3D 0x9000000000200000 +endif bootvars-y =3D VMLINUX_LOAD_ADDRESS=3D$(load-y) =20 drivers-$(CONFIG_PCI) +=3D arch/loongarch/pci/ diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile index 20b64ac3f128..df5aea129364 100644 --- a/arch/loongarch/kernel/Makefile +++ b/arch/loongarch/kernel/Makefile @@ -17,7 +17,8 @@ obj-$(CONFIG_CPU_HAS_FPU) +=3D fpu.o obj-$(CONFIG_MODULES) +=3D module.o module-sections.o obj-$(CONFIG_STACKTRACE) +=3D stacktrace.o =20 -obj-$(CONFIG_KEXEC) +=3D machine_kexec.o relocate_kernel.o +obj-$(CONFIG_KEXEC) +=3D machine_kexec.o relocate_kernel.o cra= sh.o +obj-$(CONFIG_CRASH_DUMP) +=3D crash_dump.o =20 obj-$(CONFIG_PROC_FS) +=3D proc.o =20 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 =3D CPU_MASK_NONE; + +#ifdef CONFIG_SMP +static void crash_shutdown_secondary(void *passed_regs) +{ + struct pt_regs *regs =3D passed_regs; + int cpu =3D 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 =3D get_irq_regs(); + if (!regs) + regs =3D 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 =3D 1; + + /* Excluding the panic cpu */ + ncpus =3D 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 =3D 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 =3D 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/cra= sh_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 =3D kmap_local_pfn(pfn); + csize =3D 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; } =20 - /* 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 =3D virt_to_page((void *)KEXEC_CTRL_CODE); =20 reboot_code_buffer =3D @@ -113,10 +113,6 @@ static void kexec_shutdown_secondary(void *) =20 kexec_reboot(); } - -void machine_crash_shutdown(struct pt_regs *regs) -{ -} #endif =20 void machine_shutdown(void) @@ -135,7 +131,8 @@ void machine_kexec(struct kimage *image) =20 jump_addr =3D (unsigned long)phys_to_virt(image->start); =20 - first_ind_entry =3D (unsigned long)phys_to_virt(image->head & PAGE_MASK); + if (image->type =3D=3D KEXEC_TYPE_DEFAULT) + first_ind_entry =3D (unsigned long)phys_to_virt(image->head & PAGE_MASK); =20 /* * The generic kexec code builds a page list with physical @@ -167,7 +164,8 @@ void machine_kexec(struct kimage *image) =20 /* * 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); =20 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 =20 #include #include @@ -61,4 +62,9 @@ void __init memblock_init(void) =20 /* 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/kerne= l/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 =20 + /* + * 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); =20 +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 =3D memblock_phys_mem_size(); + ret =3D parse_crashkernel(boot_command_line, total_mem, + &crash_size, &crash_base); + if (ret !=3D 0 || crash_size <=3D 0) + return; + + + start =3D memblock_phys_alloc_range(crash_size, 1, crash_base, + crash_base + crash_size); + if (start !=3D crash_base) { + pr_warn("Invalid memory region reserved for crash kernel\n"); + return; + } + + crashk_res.start =3D crash_base; + crashk_res.end =3D crash_base + crash_size - 1; +#endif +} + +static void __init request_crashkernel(struct resource *res) +{ +#ifdef CONFIG_KEXEC + int ret; + + if (crashk_res.start =3D=3D crashk_res.end) + return; + + ret =3D 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) =20 check_kernel_sections_mem(); =20 + 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); } } =20 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 *re= gs) =20 oops_exit(); =20 + if (regs && kexec_should_crash(current)) + crash_kexec(regs); + if (in_interrupt()) panic("Fatal exception in interrupt"); =20 --=20 2.36.0