SoC devices like the Intel / MaxLinear Lightning Mountain must be reset
by the Reset Control Unit (RCU) instead of using  "normal"
x86 mechanisms like ACPI, BIOS, KBD, etc.

Therefore, the RCU driver (reset-intel-gw) registers a restart handler
which triggers the global reset signal.

Unfortunately, this is of no use as long as the restart chain is not
processed during reboot on x86 systems.

That's why do_kernel_restart() must be called when a reboot is
performed. This has long been common practice for other architectures.

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
---
Changes in v2:
- Updated the commit message.
- Link to v1: https://lore.kernel.org/r/20260220-x86_do_kernel_restart-v1-1-a0cee49bbc80@dev.tdt.de
---
 arch/x86/kernel/reboot.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 6032fa9ec753ce938b1b523a7eab76370ee802de..ddff25a1efbe71171ca22ec21f50541517c1a464 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -773,12 +773,15 @@ static void __machine_emergency_restart(int emergency)
 	machine_ops.emergency_restart();
 }
 
-static void native_machine_restart(char *__unused)
+static void native_machine_restart(char *command)
 {
 	pr_notice("machine restart\n");
 
 	if (!reboot_force)
 		machine_shutdown();
+
+	do_kernel_restart(command);
+
 	__machine_emergency_restart(0);
 }
 

---
base-commit: 05f7e89ab9731565d8a62e3b5d1ec206485eeb0b
change-id: 20260220-x86_do_kernel_restart-ac125c71c5c3

Best regards,
-- 
Martin Schiller <ms@dev.tdt.de>

The following commit has been merged into the x86/misc branch of tip:

Commit-ID:     ae715818c5d7e486fe97806a734205cea63921e2
Gitweb:        https://git.kernel.org/tip/ae715818c5d7e486fe97806a734205cea63921e2
Author:        Martin Schiller <ms@dev.tdt.de>
AuthorDate:    Wed, 25 Feb 2026 08:46:09 +01:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Thu, 05 Mar 2026 16:22:43 +01:00

x86/reboot: Execute the kernel restart handler upon machine restart

SoC devices like the Intel / MaxLinear Lightning Mountain must be reset by the
Reset Control Unit (RCU) instead of using  "normal" x86 mechanisms like ACPI,
BIOS, KBD, etc.

Therefore, the RCU driver (reset-intel-gw) registers a restart handler which
triggers the global reset signal.

Unfortunately, this is of no use as long as the restart chain is not processed
during reboot on x86 systems.

That's why do_kernel_restart() must be called when a reboot is performed. This
has long been common practice for other architectures.

  [ bp: Massage commit message. ]

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260225-x86_do_kernel_restart-v2-1-81396cf3d44c@dev.tdt.de
---
 arch/x86/kernel/reboot.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 6032fa9..ddff25a 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -773,12 +773,15 @@ static void __machine_emergency_restart(int emergency)
 	machine_ops.emergency_restart();
 }
 
-static void native_machine_restart(char *__unused)
+static void native_machine_restart(char *command)
 {
 	pr_notice("machine restart\n");
 
 	if (!reboot_force)
 		machine_shutdown();
+
+	do_kernel_restart(command);
+
 	__machine_emergency_restart(0);
 }