x86, realmode: Change EFER to a single u64 field

Change EFER to be a single u64 field instead of two u32 fields; change
the order to maintain alignment.  Note that on x86-64 cr4 is really
also a 64-bit quantity, although we can only set the low 32 bits from
the trampoline code since it is still executing in 32-bit mode at that
point.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 099277984b80..cbca565af5bd 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -22,7 +22,7 @@ void __init setup_real_mode(void)
         size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
 #ifdef CONFIG_X86_64
         u64 *trampoline_pgd;
-        u32 efer_low, efer_high;
+        u64 efer;
 #endif
 
         /* Has to be in very low memory so we can execute real-mode AP code. */
@@ -70,9 +70,8 @@ void __init setup_real_mode(void)
          * Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
          * so we need to mask it out.
          */
-        rdmsr(MSR_EFER, efer_low, efer_high);
-        trampoline_header->efer_low  = efer_low & ~EFER_LMA;
-        trampoline_header->efer_high = efer_high;
+        rdmsrl(MSR_EFER, efer);
+        trampoline_header->efer = efer & ~EFER_LMA;
 
         trampoline_header->start = (u64) secondary_startup_64;
         trampoline_cr4_features = &trampoline_header->cr4;