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.
Signed-off-by: Geoff Levand <[email protected]> --- 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. -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 [email protected] http://lists.infradead.org/mailman/listinfo/kexec
