From 2a5ec3a553f7b23359344d52332263d5fa88aac6 Mon Sep 17 00:00:00 2001 From: Yangyang Lian Date: Tue, 27 Oct 2026 22:51:35 +0800 Subject: [PATCH] LoongArch: Add arch_crash_save_vmcoreinfo() support Since commit 23c85094fe18 ("proc/kcore: add vmcoreinfo note to /proc/ kcore") the kernel has exported the vmcoreinfo PT_NOTE on /proc/kcore as well as /proc/vmcore. LoongArch does not provide arch_crash_save_vmcoreinfo(), so the arch- specific values are missing from the vmcoreinfo PT_NOTE. The generic exporter in kernel/vmcore_info.c already provides NUMBER(VMALLOC_START), but tools like crash cannot derive VMALLOC_END, the module and vmemmap ranges, VA_BITS, or the KASLR offset of a LoongArch dump. Since commit 18210a104bb9 ("LoongArch: Expand module virtual address space to 2GB") the vmalloc and module boundaries are no longer stable across kernel versions either, so vmcoreinfo is the only reliable source for them. Provide this function in a separate file that is built at the same time as its caller in kernel/vmcore_info.c, and add a LOONGARCH64 section to Documentation/admin-guide/kdump/vmcoreinfo.rst. Reported-by: Haoran Jiang Suggested-by: Haoran Jiang Tested-by: Tao Cui Co-developed-by: George Guo Signed-off-by: George Guo Signed-off-by: Yangyang Lian Signed-off-by: Huacai Chen --- .../admin-guide/kdump/vmcoreinfo.rst | 36 +++++++++++++++++++ arch/loongarch/kernel/Makefile | 1 + arch/loongarch/kernel/vmcore_info.c | 22 ++++++++++++ 3 files changed, 59 insertions(+) create mode 100644 arch/loongarch/kernel/vmcore_info.c diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst index 7663c610fe90..e948095888fe 100644 --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst @@ -594,3 +594,39 @@ va_kernel_pa_offset Indicates the offset between the kernel virtual and physical mappings. Used to translate virtual to physical addresses. + +LOONGARCH64 +=========== + +VA_BITS +------- + +The maximum number of bits for virtual addresses. Used to compute the +virtual memory ranges. + +PHYS_OFFSET +----------- + +Indicates the physical address of the start of memory. Used to translate +virtual to physical addresses. + +PAGE_OFFSET +----------- + +Indicates the virtual kernel start address of the direct-mapped RAM region. +Used together with PHYS_OFFSET to translate between virtual and physical +addresses. + +KERNELOFFSET +------------ + +The kernel randomization offset. Used to locate the kernel text in virtual +memory. If KASLR is disabled, this value is zero. + +MODULES_VADDR|MODULES_END|VMALLOC_START|VMALLOC_END|VMEMMAP_START|VMEMMAP_END +----------------------------------------------------------------------------- + +Used to get the correct ranges: + MODULES_VADDR ~ MODULES_END-1 : Kernel module space. + VMALLOC_START ~ VMALLOC_END-1 : vmalloc() / ioremap() space. + VMEMMAP_START ~ VMEMMAP_END-1 : vmemmap region, used for struct page array. diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile index 001924877772..6260c15adaba 100644 --- a/arch/loongarch/kernel/Makefile +++ b/arch/loongarch/kernel/Makefile @@ -64,6 +64,7 @@ obj-$(CONFIG_RELOCATABLE) += relocate.o obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o obj-$(CONFIG_KEXEC_FILE) += machine_kexec_file.o kexec_efi.o kexec_elf.o obj-$(CONFIG_CRASH_DUMP) += crash_dump.o +obj-$(CONFIG_VMCORE_INFO) += vmcore_info.o obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o diff --git a/arch/loongarch/kernel/vmcore_info.c b/arch/loongarch/kernel/vmcore_info.c new file mode 100644 index 000000000000..e4efc35165b1 --- /dev/null +++ b/arch/loongarch/kernel/vmcore_info.c @@ -0,0 +1,22 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include + +void arch_crash_save_vmcoreinfo(void) +{ + VMCOREINFO_NUMBER(VA_BITS); + /* NUMBER(VMALLOC_START) is exported by the generic code */ + vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", VMALLOC_END); +#ifdef CONFIG_64BIT + vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", MODULES_VADDR); + vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", MODULES_END); + vmcoreinfo_append_str("NUMBER(VMEMMAP_START)=0x%lx\n", (unsigned long)vmemmap); + vmcoreinfo_append_str("NUMBER(VMEMMAP_END)=0x%lx\n", VMEMMAP_END + 1); +#endif + vmcoreinfo_append_str("NUMBER(PHYS_OFFSET)=0x%lx\n", PHYS_OFFSET); + vmcoreinfo_append_str("NUMBER(PAGE_OFFSET)=0x%lx\n", PAGE_OFFSET); + vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); +}