[PATCH] kexec: do KEXEC_FILE_LOAD and fallback to KEXEC_LOAD if not supported.
Baoquan He
bhe at redhat.com
Thu Feb 22 15:20:43 PST 2018
Hi Michal,
On 02/22/18 at 11:24pm, Michal Suchanek wrote:
> The new KEXEC_FILE_LOAD is preferred in the case the platform supports
> it because it allows kexec in locked down secure boot mode.
>
> However, some platforms do not support it so fall back to the old
> syscall there.
I didn't read code change, just from patch log, I tend to not agree. There
are two options KEXEC_FILE_LOAD and KEXEC_LOAD, some platforms do not
support, why does some platforms not choose KEXEC_LOAD, the working one?
Why bother to make change in code? I believe there's returned message
telling if KEXEC_FILE_LOAD works or not.
Thanks
Baoquan
>
> Also provide an option to call the old syscall in case the new syscall
> fails with other reason than ENOSYS.
>
> Also document the options.
>
> Signed-off-by: Michal Suchanek <msuchanek at suse.de>
> ---
> kexec/kexec.8 | 9 +++++++++
> kexec/kexec.c | 41 +++++++++++++++--------------------------
> kexec/kexec.h | 2 ++
> 3 files changed, 26 insertions(+), 26 deletions(-)
>
> diff --git a/kexec/kexec.8 b/kexec/kexec.8
> index e0131b4ea827..7e4df723251d 100644
> --- a/kexec/kexec.8
> +++ b/kexec/kexec.8
> @@ -144,6 +144,15 @@ Load the new kernel for use on panic.
> Specify that the new kernel is of this
> .I type.
> .TP
> +.BI \-s\ (\-\-kexec-file-syscall)
> +Specify that the new KEXEC_FILE_LOAD syscall should be used exclusively.
> +Otherwise KEXEC_FILE_LOAD is tried and when not supported KEXEC_LOAD is used.
> +.I type.
> +.TP
> +.BI \-c\ (\-\-kexec-syscall)
> +Specify that the old KEXEC_LOAD syscall should be used exclusively.
> +.I type.
> +.TP
> .B \-u\ (\-\-unload)
> Unload the current
> .B kexec
> diff --git a/kexec/kexec.c b/kexec/kexec.c
> index cfd837c1b6bb..25328c02b508 100644
> --- a/kexec/kexec.c
> +++ b/kexec/kexec.c
> @@ -1166,7 +1166,7 @@ static int do_kexec_file_load(int fileind, int argc, char **argv,
>
> if (!is_kexec_file_load_implemented()) {
> fprintf(stderr, "syscall kexec_file_load not available.\n");
> - return -1;
> + return -ENOSYS;
> }
>
> if (argc - fileind <= 0) {
> @@ -1243,6 +1243,7 @@ int main(int argc, char *argv[])
> int do_unload = 0;
> int do_reuse_initrd = 0;
> int do_kexec_file_syscall = 0;
> + int do_kexec_syscall = 0;
> int do_status = 0;
> void *entry = 0;
> char *type = 0;
> @@ -1256,19 +1257,6 @@ int main(int argc, char *argv[])
> };
> static const char short_options[] = KEXEC_ALL_OPT_STR;
>
> - /*
> - * First check if --use-kexec-file-syscall is set. That changes lot of
> - * things
> - */
> - while ((opt = getopt_long(argc, argv, short_options,
> - options, 0)) != -1) {
> - switch(opt) {
> - case OPT_KEXEC_FILE_SYSCALL:
> - do_kexec_file_syscall = 1;
> - break;
> - }
> - }
> -
> /* Reset getopt for the next pass. */
> opterr = 1;
> optind = 1;
> @@ -1310,8 +1298,7 @@ int main(int argc, char *argv[])
> do_shutdown = 0;
> do_sync = 0;
> do_unload = 1;
> - if (do_kexec_file_syscall)
> - kexec_file_flags |= KEXEC_FILE_UNLOAD;
> + kexec_file_flags |= KEXEC_FILE_UNLOAD;
> break;
> case OPT_EXEC:
> do_load = 0;
> @@ -1354,11 +1341,8 @@ int main(int argc, char *argv[])
> do_exec = 0;
> do_shutdown = 0;
> do_sync = 0;
> - if (do_kexec_file_syscall)
> - kexec_file_flags |= KEXEC_FILE_ON_CRASH;
> - else
> - kexec_flags = KEXEC_ON_CRASH;
> - break;
> + kexec_file_flags |= KEXEC_FILE_ON_CRASH;
> + kexec_flags = KEXEC_ON_CRASH;
> case OPT_MEM_MIN:
> mem_min = strtoul(optarg, &endptr, 0);
> if (*endptr) {
> @@ -1383,7 +1367,12 @@ int main(int argc, char *argv[])
> do_reuse_initrd = 1;
> break;
> case OPT_KEXEC_FILE_SYSCALL:
> - /* We already parsed it. Nothing to do. */
> + do_kexec_file_syscall = 1;
> + do_kexec_syscall = 0;
> + break;
> + case OPT_KEXEC_SYSCALL:
> + do_kexec_file_syscall = 0;
> + do_kexec_syscall = 1;
> break;
> case OPT_STATUS:
> do_status = 1;
> @@ -1456,16 +1445,16 @@ int main(int argc, char *argv[])
> result = k_status(kexec_flags);
> }
> if (do_unload) {
> - if (do_kexec_file_syscall)
> + if (!do_kexec_syscall)
> result = kexec_file_unload(kexec_file_flags);
> - else
> + if ((result == -ENOSYS) || !do_kexec_file_syscall)
> result = k_unload(kexec_flags);
> }
> if (do_load && (result == 0)) {
> - if (do_kexec_file_syscall)
> + if (!do_kexec_syscall)
> result = do_kexec_file_load(fileind, argc, argv,
> kexec_file_flags);
> - else
> + if ((result == -ENOSYS) || !do_kexec_file_syscall)
> result = my_load(type, fileind, argc, argv,
> kexec_flags, entry);
> }
> diff --git a/kexec/kexec.h b/kexec/kexec.h
> index 26225d2c002a..7abcec796cae 100644
> --- a/kexec/kexec.h
> +++ b/kexec/kexec.h
> @@ -219,6 +219,7 @@ extern int file_types;
> #define OPT_TYPE 't'
> #define OPT_PANIC 'p'
> #define OPT_KEXEC_FILE_SYSCALL 's'
> +#define OPT_KEXEC_SYSCALL 'c'
> #define OPT_STATUS 'S'
> #define OPT_MEM_MIN 256
> #define OPT_MEM_MAX 257
> @@ -246,6 +247,7 @@ extern int file_types;
> { "mem-max", 1, 0, OPT_MEM_MAX }, \
> { "reuseinitrd", 0, 0, OPT_REUSE_INITRD }, \
> { "kexec-file-syscall", 0, 0, OPT_KEXEC_FILE_SYSCALL }, \
> + { "kexec-syscall", 0, 0, OPT_KEXEC_SYSCALL }, \
> { "debug", 0, 0, OPT_DEBUG }, \
> { "status", 0, 0, OPT_STATUS }, \
> { "print-ckr-size", 0, 0, OPT_PRINT_CKR_SIZE }, \
> --
> 2.13.6
>
>
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