[PATCH 2/2] efi/arm64: use UEFI for system reset
From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2014-08-29 16:04:48
On Fri, Aug 29, 2014 at 04:05:57PM +0100, Ard Biesheuvel wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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. + */
Why do you make this the preferred method? Is there a risk that UEFI is broken and we want to override it with a SoC-specific driver (I wouldn't like it but it's still an option). There are also some patches here that try to get rid of arm_pm_restart: https://lkml.org/lkml/2014/8/19/665 Once there are no drivers for arm64 setting arm_pm_restart explicitly I'll remove it.
+ if (IS_ENABLED(CONFIG_EFI) && efi_enabled(EFI_RUNTIME_SERVICES))
efi_enabled always returns false if !IS_ENABLED(CONFIG_EFI).
+ 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
-- Catalin