On 10/21/15 at 04:12pm, Geoff Levand wrote:
> Add a new option --lite to kexec that allows for a fast reboot
> by avoiding the purgatory integrity checks. This option is
> intended for use by kexec based bootloaders that load a new
> image and then immediately transfer control to it.
I think Vivek was rejecting this --lite since kdump need the purgatory
integrity checks. Ccing him.
>
> Signed-off-by: Geoff Levand <geoff at infradead.org>
> ---
> Hi Simon,
>
> It was reported that on some systems where purgatory is running
> without caches enabled the sha256 calculations would take several
> minutes. For bootloaders that just load a new image and
> immediately jump into it the loss of the integrity check is worth
> the increase in boot speed. Please consider.
Pratyush reported the arm64 issue, he sent a patch to fix it with
enabling cache for purgatory. I think the patch can fix the problem.
Why not fix it? The fix is simple enough and it does not introduce
complicate logic.
>
> -Geoff
>
> kexec/kexec.8 | 3 +++
> kexec/kexec.c | 19 +++++++++++++++++--
> kexec/kexec.h | 4 ++++
> purgatory/purgatory.c | 3 ++-
> 4 files changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/kexec/kexec.8 b/kexec/kexec.8
> index 4d0c1d1..93ed588 100644
> --- a/kexec/kexec.8
> +++ b/kexec/kexec.8
> @@ -126,6 +126,9 @@ in one call.
> Open a help file for
> .BR kexec .
> .TP
> +.B \-i\ (\-\-lite)
> +Fast reboot, no memory integrity checks.
> +.TP
> .BI \-l\ (\-\-load) \ kernel
> Load the specified
> .I kernel
> diff --git a/kexec/kexec.c b/kexec/kexec.c
> index ff024f3..ebb1310 100644
> --- a/kexec/kexec.c
> +++ b/kexec/kexec.c
> @@ -613,6 +613,15 @@ static void update_purgatory(struct kexec_info *info)
> return;
> }
> arch_update_purgatory(info);
> +
> + if (info->kexec_lite) {
> + unsigned int tmp = 1;
> +
> + elf_rel_set_symbol(&info->rhdr, "kexec_lite", &tmp,
> + sizeof(tmp));
> + return;
> + }
> +
> memset(region, 0, sizeof(region));
> sha256_starts(&ctx);
> /* Compute a hash of the loaded kernel */
> @@ -652,7 +661,7 @@ static void update_purgatory(struct kexec_info *info)
> * Load the new kernel
> */
> static int my_load(const char *type, int fileind, int argc, char **argv,
> - unsigned long kexec_flags, void *entry)
> + unsigned long kexec_flags, int kexec_lite, void *entry)
> {
> char *kernel;
> char *kernel_buf;
> @@ -665,6 +674,7 @@ static int my_load(const char *type, int fileind, int argc, char **argv,
>
> memset(&info, 0, sizeof(info));
> info.kexec_flags = kexec_flags;
> + info.kexec_lite = kexec_lite;
>
> result = 0;
> if (argc - fileind <= 0) {
> @@ -914,6 +924,7 @@ void usage(void)
> " -v, --version Print the version of kexec.\n"
> " -f, --force Force an immediate kexec,\n"
> " don't call shutdown.\n"
> + " -i, --lite Fast reboot, no memory integrity checks.\n"
> " -x, --no-ifdown Don't bring down network interfaces.\n"
> " -y, --no-sync Don't sync filesystems before kexec.\n"
> " -l, --load Load the new kernel into the\n"
> @@ -1173,6 +1184,7 @@ int main(int argc, char *argv[])
> int do_unload = 0;
> int do_reuse_initrd = 0;
> int do_kexec_file_syscall = 0;
> + int do_lite = 0;
> void *entry = 0;
> char *type = 0;
> char *endptr;
> @@ -1314,6 +1326,9 @@ int main(int argc, char *argv[])
> case OPT_KEXEC_FILE_SYSCALL:
> /* We already parsed it. Nothing to do. */
> break;
> + case OPT_LITE:
> + do_lite = 1;
> + break;
> default:
> break;
> }
> @@ -1374,7 +1389,7 @@ int main(int argc, char *argv[])
> kexec_file_flags);
> else
> result = my_load(type, fileind, argc, argv,
> - kexec_flags, entry);
> + kexec_flags, do_lite, entry);
> }
> /* Don't shutdown unless there is something to reboot to! */
> if ((result == 0) && (do_shutdown || do_exec) && !kexec_loaded()) {
> diff --git a/kexec/kexec.h b/kexec/kexec.h
> index 7c97b25..06e08f4 100644
> --- a/kexec/kexec.h
> +++ b/kexec/kexec.h
> @@ -165,6 +165,8 @@ struct kexec_info {
> int initrd_fd;
> char *command_line;
> int command_line_len;
> +
> + int kexec_lite;
> };
>
> struct arch_map_entry {
> @@ -218,6 +220,7 @@ extern int file_types;
> #define OPT_TYPE 't'
> #define OPT_PANIC 'p'
> #define OPT_KEXEC_FILE_SYSCALL 's'
> +#define OPT_LITE 'i'
> #define OPT_MEM_MIN 256
> #define OPT_MEM_MAX 257
> #define OPT_REUSE_INITRD 258
> @@ -243,6 +246,7 @@ 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 }, \
> + { "lite", 0, 0, OPT_LITE }, \
> { "debug", 0, 0, OPT_DEBUG }, \
>
> #define KEXEC_OPT_STR "h?vdfxyluet:ps"
> diff --git a/purgatory/purgatory.c b/purgatory/purgatory.c
> index 3bbcc09..7e99b92 100644
> --- a/purgatory/purgatory.c
> +++ b/purgatory/purgatory.c
> @@ -8,6 +8,7 @@
>
> struct sha256_region sha256_regions[SHA256_REGIONS] = {};
> sha256_digest_t sha256_digest = { };
> +int kexec_lite = 0;
>
> int verify_sha256_digest(void)
> {
> @@ -43,7 +44,7 @@ void purgatory(void)
> {
> printf("I'm in purgatory\n");
> setup_arch();
> - if (verify_sha256_digest()) {
> + if (!kexec_lite && verify_sha256_digest()) {
> for(;;) {
> /* loop forever */
> }
> --
> 2.5.0
>
>
> _______________________________________________
> kexec mailing list
> kexec at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
>
>
