[PATCH 2/2] efi/arm64: use UEFI for system reset

[ard.biesheuvel@linaro.org (Ard Biesheuvel)]

If UEFI Runtime Services are available, they are preferred over direct
PSCI calls or other methods to reset the system.

For the reset case, we need to hook into machine_restart(), as the
arm_pm_restart function pointer may be overwritten by modules.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/kernel/process.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 1309d64aa926..335a93da5eeb 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -177,6 +177,13 @@ void machine_restart(char *cmd)
 	local_irq_disable();
 	smp_send_stop();
 
+	/*
+	 * arm_pm_restart is exported to modules, so the only way to supersede
+	 * it with efi_reboot() is to call it here.
+	 */
+	if (IS_ENABLED(CONFIG_EFI) && efi_enabled(EFI_RUNTIME_SERVICES))
+		efi_reboot(REBOOT_WARM, NULL);
+
 	/* Now call the architecture specific reboot code. */
 	if (arm_pm_restart)
 		arm_pm_restart(reboot_mode, cmd);
-- 
1.8.3.2