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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