[PATCH v5 4/5] kexec: Add option to fall back to KEXEC_LOAD when KEXEC_FILE_LOAD is not supported
Dave Young
dyoung at redhat.com
Mon Mar 26 02:12:10 PDT 2018
On 03/26/18 at 05:08pm, Dave Young wrote:
> On 03/20/18 at 04:56pm, Michal Suchanek wrote:
> > Not all architectures implement KEXEC_FILE_LOAD. However, on some
> > archiectures KEXEC_FILE_LOAD is required when secure boot is enabled in
> > locked-down mode. Previously users had to select the KEXEC_FILE_LOAD
> > syscall with undocumented -s option. However, if they did pass the
> > option kexec would fail on architectures that do not support it.
> >
> > So add an -a option that tries KEXEC_FILE_LOAD and when it is not
> > supported tries KEXEC_LOAD.
> >
> > Signed-off-by: Michal Suchanek <msuchanek at suse.de>
> > ---
> > v3: instead of changing the deafult add extra option
> > v4: actually check -ENOSYS as well
> > v5: add missing break
> > ---
> > kexec/kexec.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++-----
> > kexec/kexec.h | 6 +++++-
> > 2 files changed, 58 insertions(+), 6 deletions(-)
> >
> > diff --git a/kexec/kexec.c b/kexec/kexec.c
> > index 68ae0594d4a7..44042345a16e 100644
> > --- a/kexec/kexec.c
> > +++ b/kexec/kexec.c
> > @@ -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_fallback = 0;
> > int do_status = 0;
> > void *entry = 0;
> > char *type = 0;
> > @@ -1367,6 +1368,15 @@ int main(int argc, char *argv[])
> > break;
> > case OPT_KEXEC_FILE_SYSCALL:
> > do_kexec_file_syscall = 1;
> > + do_kexec_fallback = 0;
> > + break;
> > + case OPT_KEXEC_SYSCALL:
> > + do_kexec_file_syscall = 0;
> > + do_kexec_fallback = 0;
> > + break;
> > + case OPT_KEXEC_SYSCALL_AUTO:
> > + do_kexec_file_syscall = 1;
> > + do_kexec_fallback = 1;
> > break;
> > case OPT_STATUS:
> > do_status = 1;
> > @@ -1433,7 +1443,7 @@ int main(int argc, char *argv[])
> > }
> > }
> > if (do_kexec_file_syscall) {
> > - if (do_load_jump_back_helper)
> > + if (do_load_jump_back_helper && !do_kexec_fallback)
> > die("--load-jump-back-helper not supported with kexec_file_load\n");
> > if (kexec_flags & KEXEC_PRESERVE_CONTEXT)
> > die("--load-preserve-context not supported with kexec_file_load\n");
> > @@ -1447,16 +1457,54 @@ int main(int argc, char *argv[])
> > result = k_status(kexec_flags);
> > }
> > if (do_unload) {
> > - if (do_kexec_file_syscall)
> > + if (do_kexec_file_syscall) {
> > result = kexec_file_unload(kexec_file_flags);
> > - else
> > + if ((result == -ENOSYS) && do_kexec_fallback)
> > + do_kexec_file_syscall = 0;
> > + }
> > + if (!do_kexec_file_syscall)
> > result = k_unload(kexec_flags);
> > }
> > if (do_load && (result == 0)) {
> > - if (do_kexec_file_syscall)
> > + if (do_kexec_file_syscall) {
> > result = do_kexec_file_load(fileind, argc, argv,
> > kexec_file_flags);
> > - else
> > + if (do_kexec_fallback) switch (result) {
> > + /*
> > + * Something failed with signature verification.
> > + * Reject the image.
> > + */
> > + case -ELIBBAD:
> > + case -EKEYREJECTED:
> > + case -ENOPKG:
> > + case -ENOKEY:
> > + case -EBADMSG:
> > + case -EMSGSIZE:
> > + /*
> > + * By default reject or do nothing if
> > + * succeded
> > + */
> > + default: break;
> > + case -ENOSYS: /* not implemented */
> > + /*
> > + * Parsing image or other options failed
> > + * The image may be invalid or image
> > + * type may not supported by kernel so
> > + * retry parsing in kexec-tools.
> > + */
> > + case -EINVAL:
> > + case -ENOEXEC:
> > + /*
> > + * ENOTSUPP can be unsupported image
> > + * type or unsupported PE signature
> > + * wrapper type, duh
> > + */
> > + case -ENOTSUP:
>
> Hmm, this is still used in latest version. kernel does not return such
> error number, I might not say clearly previously. Please check the
> kernel code, the only one place I know is because no kdump support in
> power kexec_file:
> arch/powerpc/kernel/machine_kexec_file_64.c
>
> /* We don't support crash kernels yet. */
> if (image->type == KEXEC_TYPE_CRASH)
> return -ENOTSUPP;
>
> So I suggest not checking this as well since -ENOTSUPP is not populated
> in userspace headers, and -ENOTSUP is not used at all.
>
> Also as I mentioned in another reply -EINVAL and -ENOEXEC is also not
> ncessary.
>
> For -ENOTSUP, maybe someone can submit a patch to switch to -ENOTSUPP
> so that userspace can check it.
> Ccing Thiago and Hari for the -ENOTSUPP errno issue.
Oops for the hurry reply, I means -ENOTSUPP might be able to replaced
with -EOPNOTSUPP, a similar change like this:
https://patchwork.kernel.org/patch/8490791/
>
> > + do_kexec_file_syscall = 0;
> > + break;
> > + }
> > + }
> > + if (!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..d445fbe3e486 100644
> > --- a/kexec/kexec.h
> > +++ b/kexec/kexec.h
> > @@ -219,6 +219,8 @@ 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_KEXEC_SYSCALL_AUTO 'a'
> > #define OPT_STATUS 'S'
> > #define OPT_MEM_MIN 256
> > #define OPT_MEM_MAX 257
> > @@ -246,11 +248,13 @@ 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 }, \
> > + { "kexec-syscall-auto", 0, 0, OPT_KEXEC_SYSCALL_AUTO }, \
> > { "debug", 0, 0, OPT_DEBUG }, \
> > { "status", 0, 0, OPT_STATUS }, \
> > { "print-ckr-size", 0, 0, OPT_PRINT_CKR_SIZE }, \
> >
> > -#define KEXEC_OPT_STR "h?vdfxyluet:psS"
> > +#define KEXEC_OPT_STR "h?vdfxyluet:pscaS"
> >
> > extern void dbgprint_mem_range(const char *prefix, struct memory_range *mr, int nr_mr);
> > extern void die(const char *fmt, ...)
> > --
> > 2.13.6
> >
> >
> > _______________________________________________
> > kexec mailing list
> > kexec at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kexec
>
> Thanks
> Dave
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