Messages in this thread | | | From | Liao Chang <> | Subject | [PATCH 0/3] riscv: kexec: add kexec_file_load() support | Date | Sat, 30 Oct 2021 11:18:29 +0800 |
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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 future work: * Support for kdump and purgatory. * Support for kernel image verification. * Support physical address randomization.
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/Kconfig | 11 ++ arch/riscv/include/asm/kexec.h | 4 + arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/elf_kexec.c | 189 +++++++++++++++++++++++++ arch/riscv/kernel/machine_kexec.c | 5 +- arch/riscv/kernel/machine_kexec_file.c | 14 ++ include/linux/kexec.h | 2 +- kernel/kexec_file.c | 4 +- 8 files changed, 226 insertions(+), 4 deletions(-) create mode 100644 arch/riscv/kernel/elf_kexec.c create mode 100644 arch/riscv/kernel/machine_kexec_file.c
-- 2.17.1
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