On Fri, 08 Apr 2022 03:09:08 PDT (-0700), [email protected] 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.
Thanks!