[RFT][PATCH] ACPI / init: Run acpi_early_init() before efi_enter_virtual_mode() (was: Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME)

Rafael J. Wysocki
2014-01-12T00:30:23Z

On Saturday, December 21, 2013 12:21:48 PM Matt Fleming wrote:
> On Fri, 20 Dec, at 11:18:56PM, Rafael J. Wysocki wrote:
> >
> > I'm not sure 100%, but I *think* we need to do that with interrupts enabled.
> > At least after mm_init(), because it relies on things initialized there if I
> > remember correctly.
> >
> > From what I can tell at the moment, it might be possible to move it before
> > efi_enter_virtual_mode() if that would help.
>
> Actually yeah, that would be super useful, and I think we'd be able to
> get rid of the whole efi_late_init() stuff because we'd no longer need
> to hang on to the EFI_BOOT_SERVICES* regions after
> SetVirtualAddressMap().

OK

I don't see any adverse effects of the patch below on a couple of my test
boxes, but (a) they are Intel-based and (b) they are non-EFI, so it would be
good to give it a go on as many machines as reasonably possible.

Thanks,
Rafael

---
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Subject: ACPI / init: Run acpi_early_init() before efi_enter_virtual_mode()

According to Matt Fleming, if acpi_early_init() was executed befpre
efi_enter_virtual_mode(), the EFI initialization could benefit from
it, so make that happen.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
init/main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-pm/init/main.c
===================================================================
--- linux-pm.orig/init/main.c
+++ linux-pm/init/main.c
@@ -615,6 +615,7 @@ asmlinkage void __init start_kernel(void
calibrate_delay();
pidmap_init();
anon_vma_init();
+ acpi_early_init();
#ifdef CONFIG_X86
if (efi_enabled(EFI_RUNTIME_SERVICES))
efi_enter_virtual_mode();
@@ -641,7 +642,6 @@ asmlinkage void __init start_kernel(void

check_bugs();

- acpi_early_init(); /* before LAPIC and SMP init */
sfi_init_late();

if (efi_enabled(EFI_RUNTIME_SERVICES)) {