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>

3 files changed, 5 insertions, 7 deletions

diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
index 937dc6071d7..fce3f4ae5bd 100644
--- a/arch/x86/include/asm/realmode.h
+++ b/arch/x86/include/asm/realmode.h
@@ -35,9 +35,8 @@ struct trampoline_header {
         u32 gdt_base;
 #else
         u64 start;
+        u64 efer;
         u32 cr4;
-        u32 efer_low;
-        u32 efer_high;
 #endif
 };
 
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 099277984b8..cbca565af5b 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;
diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S
index 1b9e1bc1ac5..bb360dc39d2 100644
--- a/arch/x86/realmode/rm/trampoline_64.S
+++ b/arch/x86/realmode/rm/trampoline_64.S
@@ -146,8 +146,8 @@ GLOBAL(trampoline_pgd)		.space	PAGE_SIZE
         .balign 8
 GLOBAL(trampoline_header)
         tr_start:               .space  8
-        GLOBAL(tr_cr4)          .space  4
         GLOBAL(tr_efer)         .space  8
+        GLOBAL(tr_cr4)          .space  4
 END(trampoline_header)
 
 #include "trampoline_common.S"