x86-64/efi: Use EFI to deal with platform wall clock (again)

Other than ix86, x86-64 on EFI so far didn't set the
{g,s}et_wallclock accessors to the EFI routines, thus
incorrectly using raw RTC accesses instead.

Simply removing the #ifdef around the respective code isn't
enough, however: While so far early get-time calls were done in
physical mode, this doesn't work properly for x86-64, as virtual
addresses would still need to be set up for all runtime regions
(which wasn't the case on the system I have access to), so
instead the patch moves the call to efi_enter_virtual_mode()
ahead (which in turn allows to drop all code related to calling
efi-get-time in physical mode).

Additionally the earlier calling of efi_set_executable()
requires the CPA code to cope, i.e. during early boot it must be
avoided to call cpa_flush_array(), as the first thing this
function does is a BUG_ON(irqs_disabled()).

Also make the two EFI functions in question here static -
they're not being referenced elsewhere.

History:

    This commit was originally merged as bacef661acdb ("x86-64/efi:
    Use EFI to deal with platform wall clock") but it resulted in some
    ASUS machines no longer booting due to a firmware bug, and so was
    reverted in f026cfa82f62. A pre-emptive fix for the buggy ASUS
    firmware was merged in 03a1c254975e ("x86, efi: 1:1 pagetable
    mapping for virtual EFI calls") so now this patch can be
    reapplied.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Matt Fleming <matt.fleming@intel.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com> [added commit history]

1 files changed, 4 insertions, 26 deletions

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index aded2a91162a..757834434e59 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -235,22 +235,7 @@ static efi_status_t __init phys_efi_set_virtual_address_map(
         return status;
 }
 
-static efi_status_t __init phys_efi_get_time(efi_time_t *tm,
-                                             efi_time_cap_t *tc)
-{
-        unsigned long flags;
-        efi_status_t status;
-
-        spin_lock_irqsave(&rtc_lock, flags);
-        efi_call_phys_prelog();
-        status = efi_call_phys2(efi_phys.get_time, virt_to_phys(tm),
-                                virt_to_phys(tc));
-        efi_call_phys_epilog();
-        spin_unlock_irqrestore(&rtc_lock, flags);
-        return status;
-}
-
-int efi_set_rtc_mmss(unsigned long nowtime)
+static int efi_set_rtc_mmss(unsigned long nowtime)
 {
         int real_seconds, real_minutes;
         efi_status_t    status;
@@ -279,7 +264,7 @@ int efi_set_rtc_mmss(unsigned long nowtime)
         return 0;
 }
 
-unsigned long efi_get_time(void)
+static unsigned long efi_get_time(void)
 {
         efi_status_t status;
         efi_time_t eft;
@@ -635,18 +620,13 @@ static int __init efi_runtime_init(void)
         }
         /*
          * We will only need *early* access to the following
-         * two EFI runtime services before set_virtual_address_map
+         * EFI runtime service before set_virtual_address_map
          * is invoked.
          */
-        efi_phys.get_time = (efi_get_time_t *)runtime->get_time;
         efi_phys.set_virtual_address_map =
                 (efi_set_virtual_address_map_t *)
                 runtime->set_virtual_address_map;
-        /*
-         * Make efi_get_time can be called before entering
-         * virtual mode.
-         */
-        efi.get_time = phys_efi_get_time;
+
         early_iounmap(runtime, sizeof(efi_runtime_services_t));
 
         return 0;
@@ -734,12 +714,10 @@ void __init efi_init(void)
                 efi_enabled = 0;
                 return;
         }
-#ifdef CONFIG_X86_32
         if (efi_native) {
                 x86_platform.get_wallclock = efi_get_time;
                 x86_platform.set_wallclock = efi_set_rtc_mmss;
         }
-#endif
 
 #if EFI_DEBUG
         print_efi_memmap();