[PATCH 0/3] kexec-tools: Add new KEXEC_FILE flags

[PATCH 0/3] kexec-tools: Add new KEXEC_FILE flags

[Brian Mak]

Hi all,

I realized I forgot to raise a patch series for adding the new kexec_file flags.
Apologies for the delay on this.

This series adds support for the KEXEC_FILE_NO_CMA and KEXEC_FILE_FORCE_DTB
flags, which are used by the --no-cma and --force-dtb options respectively.

I also saw that there's no debug print for the flags passed to kexec_file_load,
so I added a print for that as well, which was useful for me to verify these
patches.

Please let me know if there's any questions or comments.

Thanks,
Brian

Brian Mak (3):
  kexec: Add support for disabling usage of CMA
  kexec: Add DTB carryover support on x86
  kexec: Add kexec_file_load debug print

 kexec/kexec-syscall.h |  2 ++
 kexec/kexec.c         | 10 ++++++++++
 kexec/kexec.h         | 10 +++++++---
 3 files changed, 19 insertions(+), 3 deletions(-)


base-commit: f75be9241accb7a75e98998040933b9f3b988ac5
-- 
2.34.1

[PATCH 1/3] kexec: Add support for disabling usage of CMA

[Brian Mak]

Add support for disabling the use of CMA for placing kexec payloads.
This is done via the --no-cma flag.

Signed-off-by: Brian Mak <makb@juniper.net>
---
 kexec/kexec-syscall.h | 1 +
 kexec/kexec.c         | 4 ++++
 kexec/kexec.h         | 8 +++++---
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/kexec/kexec-syscall.h b/kexec/kexec-syscall.h
index b60804f..77e6b81 100644
--- a/kexec/kexec-syscall.h
+++ b/kexec/kexec-syscall.h
@@ -128,6 +128,7 @@ static inline long kexec_file_load(int kernel_fd, int initrd_fd,
 #define KEXEC_FILE_ON_CRASH	0x00000002
 #define KEXEC_FILE_NO_INITRAMFS	0x00000004
 #define KEXEC_FILE_DEBUG	0x00000008
+#define KEXEC_FILE_NO_CMA	0x00000010
 
 /* These values match the ELF architecture values. 
  * Unless there is a good reason that should continue to be the case.
diff --git a/kexec/kexec.c b/kexec/kexec.c
index 4a49ad4..ccdf4cd 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -1102,6 +1102,7 @@ void usage(void)
 	       " --hotplug            Do in-kernel update of kexec segments on CPU/Memory\n"
 	       "                      hot add/remove events, avoiding the need to reload\n"
 	       "                      kdump kernel on online/offline events.\n"
+	       " --no-cma             Don't use CMA for placing kexec payloads.\n"
 	       " -d, --debug          Enable debugging to help spot a failure.\n"
 	       " -S, --status         Return 1 if the type (by default crash) is loaded,\n"
 	       "                      0 if not.\n"
@@ -1675,6 +1676,9 @@ int main(int argc, char *argv[])
 		case OPT_HOTPLUG:
 			do_hotplug = 1;
 			break;
+		case OPT_NO_CMA:
+			kexec_file_flags |= KEXEC_FILE_NO_CMA;
+			break;
 		default:
 			break;
 		}
diff --git a/kexec/kexec.h b/kexec/kexec.h
index d0bccb5..a1edc1e 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -234,8 +234,9 @@ extern int file_types;
 #define OPT_PRINT_CKR_SIZE	262
 #define OPT_LOAD_LIVE_UPDATE	263
 #define OPT_EXEC_LIVE_UPDATE	264
-#define OPT_HOTPLUG		        265
-#define OPT_MAX		266
+#define OPT_HOTPLUG		265
+#define OPT_NO_CMA		266
+#define OPT_MAX		267
 #define KEXEC_OPTIONS \
 	{ "help",		0, 0, OPT_HELP }, \
 	{ "version",		0, 0, OPT_VERSION }, \
@@ -262,7 +263,8 @@ extern int file_types;
 	{ "debug",		0, 0, OPT_DEBUG }, \
 	{ "status",		0, 0, OPT_STATUS }, \
 	{ "print-ckr-size",     0, 0, OPT_PRINT_CKR_SIZE }, \
-	{ "hotplug",		    0, 0, OPT_HOTPLUG }, \
+	{ "hotplug",		0, 0, OPT_HOTPLUG }, \
+	{ "no-cma",		0, 0, OPT_NO_CMA }, \
 
 #define KEXEC_OPT_STR "h?vdfixyluet:pscaS"
 
-- 
2.34.1

[PATCH 2/3] kexec: Add DTB carryover support on x86

[Brian Mak]

Add support for forcing the carryover of the current boot's device tree
blob on x86. This is enabled via the --force-dtb flag.

Signed-off-by: Brian Mak <makb@juniper.net>
---
 kexec/kexec-syscall.h | 1 +
 kexec/kexec.c         | 5 +++++
 kexec/kexec.h         | 4 +++-
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/kexec/kexec-syscall.h b/kexec/kexec-syscall.h
index 77e6b81..d66bd82 100644
--- a/kexec/kexec-syscall.h
+++ b/kexec/kexec-syscall.h
@@ -129,6 +129,7 @@ static inline long kexec_file_load(int kernel_fd, int initrd_fd,
 #define KEXEC_FILE_NO_INITRAMFS	0x00000004
 #define KEXEC_FILE_DEBUG	0x00000008
 #define KEXEC_FILE_NO_CMA	0x00000010
+#define KEXEC_FILE_FORCE_DTB	0x00000020
 
 /* These values match the ELF architecture values. 
  * Unless there is a good reason that should continue to be the case.
diff --git a/kexec/kexec.c b/kexec/kexec.c
index ccdf4cd..acf9699 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -1103,6 +1103,8 @@ void usage(void)
 	       "                      hot add/remove events, avoiding the need to reload\n"
 	       "                      kdump kernel on online/offline events.\n"
 	       " --no-cma             Don't use CMA for placing kexec payloads.\n"
+	       " --force-dtb          Carry over the current boot's device tree blob (x86\n"
+	       "                      only, this is forced on ARM64 and PPC).\n"
 	       " -d, --debug          Enable debugging to help spot a failure.\n"
 	       " -S, --status         Return 1 if the type (by default crash) is loaded,\n"
 	       "                      0 if not.\n"
@@ -1679,6 +1681,9 @@ int main(int argc, char *argv[])
 		case OPT_NO_CMA:
 			kexec_file_flags |= KEXEC_FILE_NO_CMA;
 			break;
+		case OPT_FORCE_DTB:
+			kexec_file_flags |= KEXEC_FILE_FORCE_DTB;
+			break;
 		default:
 			break;
 		}
diff --git a/kexec/kexec.h b/kexec/kexec.h
index a1edc1e..1489ec3 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -236,7 +236,8 @@ extern int file_types;
 #define OPT_EXEC_LIVE_UPDATE	264
 #define OPT_HOTPLUG		265
 #define OPT_NO_CMA		266
-#define OPT_MAX		267
+#define OPT_FORCE_DTB		267
+#define OPT_MAX		268
 #define KEXEC_OPTIONS \
 	{ "help",		0, 0, OPT_HELP }, \
 	{ "version",		0, 0, OPT_VERSION }, \
@@ -265,6 +266,7 @@ extern int file_types;
 	{ "print-ckr-size",     0, 0, OPT_PRINT_CKR_SIZE }, \
 	{ "hotplug",		0, 0, OPT_HOTPLUG }, \
 	{ "no-cma",		0, 0, OPT_NO_CMA }, \
+	{ "force-dtb",		0, 0, OPT_FORCE_DTB }, \
 
 #define KEXEC_OPT_STR "h?vdfixyluet:pscaS"
 
-- 
2.34.1

[PATCH 3/3] kexec: Add kexec_file_load debug print

[Brian Mak]

Add a debug print before kexec_file_load to print the flags passed to
the syscall.

Signed-off-by: Brian Mak <makb@juniper.net>
---
 kexec/kexec.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kexec/kexec.c b/kexec/kexec.c
index acf9699..58cab57 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -1422,6 +1422,7 @@ static int do_kexec_file_load(int fileind, int argc, char **argv,
 	if (info.initrd_fd == -1)
 		info.kexec_flags |= KEXEC_FILE_NO_INITRAMFS;
 
+	dbgprintf("kexec_file_load: flags = 0x%lx\n", info.kexec_flags);
 	ret = kexec_file_load(kernel_fd, info.initrd_fd, info.command_line_len,
 			info.command_line, info.kexec_flags);
 	if (ret != 0) {
-- 
2.34.1

Re: [PATCH 0/3] kexec-tools: Add new KEXEC_FILE flags

[Simon Horman]

On Fri, Jun 12, 2026 at 03:39:42PM -0700, Brian Mak wrote:
> Hi all,
> 
> I realized I forgot to raise a patch series for adding the new kexec_file flags.
> Apologies for the delay on this.
> 
> This series adds support for the KEXEC_FILE_NO_CMA and KEXEC_FILE_FORCE_DTB
> flags, which are used by the --no-cma and --force-dtb options respectively.
> 
> I also saw that there's no debug print for the flags passed to kexec_file_load,
> so I added a print for that as well, which was useful for me to verify these
> patches.
> 
> Please let me know if there's any questions or comments.

Thanks, and likewise sorry for the delay.

Applied as:
- kexec: Add kexec_file_load debug print
  https://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git/commit/?id=29898e149feb
- kexec: Add DTB carryover support on x86
  https://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git/commit/?id=d5a495bfbfc9
- kexec: Add support for disabling usage of CMA
  https://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git/commit/?id=e4de788721cb