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path: root/arch/loongarch/kernel/mem.c
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2022-10-12LoongArch: Add kdump supportYouling Tang
This patch adds support for kdump. In kdump case the normal 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, such as kexec-tools, is responsible for allocating a separate region for the core's ELF header within the crash kdump kernel memory and filling it in when executing kexec_load(). Then, its location will be advertised to the crash dump kernel via a command line argument "elfcorehdr=", and the crash dump kernel will preserve this region for later use with arch_reserve_vmcore() at boot time. At the same time, the crash kdump kernel is also limited within the "crashkernel" area via a command line argument "mem=", so as not to destroy the original kernel dump data. In the crash dump kernel environment, /proc/vmcore is used to access the primary kernel's memory with copy_oldmem_page(). I tested kdump on LoongArch machines (Loongson-3A5000) and it works as expected (suggested crashkernel parameter is "crashkernel=512M@2560M"), 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 <tangyouling@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-06-03LoongArch: Add boot and setup routinesHuacai Chen
Add basic boot, setup and reset routines for LoongArch. Now, LoongArch machines use UEFI-based firmware. The firmware passes configuration information to the kernel via ACPI and DMI/SMBIOS. Currently an existing interface between the kernel and the bootloader is implemented. Kernel gets 2 values from the bootloader, passed in registers a0 and a1; a0 is an "EFI boot flag" distinguishing UEFI and non-UEFI firmware, while a1 is a pointer to an FDT with systable, memmap, cmdline and initrd information. The standard UEFI boot protocol (EFISTUB) will be added later. Cc: linux-efi@vger.kernel.org Cc: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Co-developed-by: Yun Liu <liuyun@loongson.cn> Signed-off-by: Yun Liu <liuyun@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>