commit cda846f101fb1396b6924f1d9b68ac3d42de5403
author Jarkko Sakkinen <jarkko.sakkinen@intel.com> Tue May 08 21:22:46 2012 +0300
committer H. Peter Anvin <hpa@linux.intel.com> Tue May 08 15:04:27 2012 -0700
tree 1fa8716c308b8e10156a1caf51d8ff6c98eceea9
parent bf8b88e97716feb750c3d34492f00d9c085e1183

x86, realmode: read cr4 and EFER from kernel for 64-bit trampoline

This patch changes 64-bit trampoline so that CR4 and
EFER are provided by the kernel instead of using fixed
values.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-24-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/include/asm/processor.h

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 4fa7dcc..404583c 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -544,13 +544,16 @@
  * enable), so that any CPU's that boot up
  * after us can get the correct flags.
  */
-extern unsigned long		mmu_cr4_features;
+extern unsigned long mmu_cr4_features;
+extern u32 *trampoline_cr4_features;
 
 static inline void set_in_cr4(unsigned long mask)
 {
 	unsigned long cr4;
 
 	mmu_cr4_features |= mask;
+	if (trampoline_cr4_features)
+		*trampoline_cr4_features = mmu_cr4_features;
 	cr4 = read_cr4();
 	cr4 |= mask;
 	write_cr4(cr4);
@@ -561,6 +564,8 @@
 	unsigned long cr4;
 
 	mmu_cr4_features &= ~mask;
+	if (trampoline_cr4_features)
+		*trampoline_cr4_features = mmu_cr4_features;
 	cr4 = read_cr4();
 	cr4 &= ~mask;
 	write_cr4(cr4);

arch/x86/include/asm/realmode.h

diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
index 1421eed..937dc60 100644
--- a/arch/x86/include/asm/realmode.h
+++ b/arch/x86/include/asm/realmode.h
@@ -24,18 +24,22 @@
 #ifdef CONFIG_X86_32
 	u32	machine_real_restart_asm;
 #endif
-} __attribute__((__packed__));
+};
 
 /* This must match data at trampoline_32/64.S */
 struct trampoline_header {
 #ifdef CONFIG_X86_32
 	u32 start;
+	u16 gdt_pad;
 	u16 gdt_limit;
 	u32 gdt_base;
 #else
 	u64 start;
+	u32 cr4;
+	u32 efer_low;
+	u32 efer_high;
 #endif
-} __attribute__((__packed__));
+};
 
 extern struct real_mode_header *real_mode_header;
 extern unsigned char real_mode_blob_end[];