Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull more x86 fixes from Peter Anvin:
 "Additional x86 fixes.  Three of these patches are pure documentation,
  two are pretty trivial; the remaining one fixes boot problems on some
  non-BIOS machines."

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Make sure we can boot in the case the BDA contains pure garbage
  x86, efi: Mark disable_runtime as __initdata
  x86, doc: Fix incorrect comment about 64-bit code segment descriptors
  doc, kernel-parameters: Document 'console=hvc<n>'
  doc, xen: Mention 'earlyprintk=xen' in the documentation.
  ACPI: Overriding ACPI tables via initrd only works with an initrd and on X86

arch/x86/kernel/head_64.S

@@ -48,7 +48,7 @@ L3_START_KERNEL = pud_index(__START_KERNEL_map)
 	.globl startup_64
 startup_64:
 	/*
-	 * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1,
+	 * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
 	 * and someone has loaded an identity mapped page table
 	 * for us.  These identity mapped page tables map all of the
 	 * kernel pages and possibly all of memory.
@@ -159,7 +159,7 @@ startup_64:
 	jmp 1f
 ENTRY(secondary_startup_64)
 	/*
-	 * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1,
+	 * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
 	 * and someone has loaded a mapped page table.
 	 *
 	 * %rsi holds a physical pointer to real_mode_data.