On Fri, 08 Apr 2022 03:09:08 PDT (-0700), lizheng...@huawei.com wrote:
This patchset implement kexec_file_load() support on riscv, Most of the code is based on the kexec-tool-patch repo developed by Nick Kossifids.This patch series enables us to load the riscv vmlinux by specifying its file decriptor, instead of user-filled buffer via kexec_file_load() syscall. `` Contrary to kexec_load() system call, we reuse the dt blob of the first kernel to the 2nd explicitly. To use kexec_file_load() system call, instead of kexec_load(), at kexec command, '-s' options must be specified. The patch for kexec_tools has to be apply to riscv architecture source like this: int elf_riscv_load(int argc, char **argv, const char *buf, off_t len, ... if (info->file_mode) { return prepare_kexec_file_options(info); } ... Add following routine to prepare cmdline_ptr, cmdline_len and initrd_fd for syscall kexec_file_load: int prepare_kexec_file_options(struct kexec_info *info) { int fd; ssize_t result; struct stat stats; if (arch_options.cmdline) { info->command_line = (char *)arch_options.cmdline; info->command_line_len = strlen(info->command_line) + 1; } if (!arch_options.initrd_path) { info->initrd_fd = -1; return 0; } fd = open(arch_options.initrd_path, O_RDONLY | _O_BINARY); if (fd < 0) { fprintf(stderr, "Cannot open `%s': %s\n", arch_options.initrd_path, strerror(errno)); return -EINVAL; } result = fstat(fd, &stats); if (result < 0) { close(fd); fprintf(stderr, "Cannot stat: %s: %s\n", arch_options.initrd_path, strerror(errno)); return -EINVAL; } info->initrd_fd = fd; return 0; } The basic usage of kexec_file is: 1) Reload capture kernel image: $ kexec -s -l <riscv-vmlinux> --reuse-cmdline 2) Startup capture kernel: $ kexec -e For kdump: 1) Reload capture kernel image: $ kexec -s -p <riscv-vmlinux> --reuse-cmdline 2) Do something to crash, like: $ echo c > /proc/sysrq-trigger v3: * Rebase on v5.18-rc1 * Workaround for -Wmissing-prototypes v2: * Support kdump * Support purgatory * Minor cleanups Li Zhengyu (3): RISC-V: Support for kexec_file on panic RISC-V: Add purgatory RISC-V: Load purgatory in kexec_file Liao Chang (3): kexec_file: Fix kexec_file.c build error for riscv platform RISC-V: use memcpy for kexec_file mode RISC-V: Add kexec_file support arch/riscv/Kbuild | 2 + arch/riscv/Kconfig | 17 + arch/riscv/include/asm/kexec.h | 4 + arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/elf_kexec.c | 448 +++++++++++++++++++++++++ arch/riscv/kernel/machine_kexec.c | 4 +- arch/riscv/kernel/machine_kexec_file.c | 14 + arch/riscv/purgatory/.gitignore | 4 + arch/riscv/purgatory/Makefile | 95 ++++++ arch/riscv/purgatory/entry.S | 47 +++ arch/riscv/purgatory/purgatory.c | 45 +++ include/linux/kexec.h | 2 +- kernel/kexec_file.c | 4 +- 13 files changed, 683 insertions(+), 4 deletions(-) create mode 100644 arch/riscv/kernel/elf_kexec.c create mode 100644 arch/riscv/kernel/machine_kexec_file.c create mode 100644 arch/riscv/purgatory/.gitignore create mode 100644 arch/riscv/purgatory/Makefile create mode 100644 arch/riscv/purgatory/entry.S create mode 100644 arch/riscv/purgatory/purgatory.c
This doesn't build on 32-bit, there's some issues both in the arch code and the generic code. Looks like nobody else supports these bits on 32-bit platforms, so I've restricted this to rv64 for now and sent along a patch set to fix everything up for 32-bit platforms.
This, with that minor Kconfig change just squashed in, is on for-next. It passes my tests, but I don't have anything specific to kexec_file() so that's probbaly not so exciting.
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