[RFC, PATCHv1 27/28] x86: enable la57 support

[Kirill A. Shutemov]

Most of things are in place and we can enable support of 5-level paging.
Things that known to be broken marked as BROKEN.

Not-yet-Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 arch/x86/Kconfig | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index df4f1d514ab0..83a4c22111b3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -309,6 +309,7 @@ config DEBUG_RODATA
 
 config PGTABLE_LEVELS
 	int
+	default 5 if X86_5LEVEL
 	default 4 if X86_64
 	default 3 if X86_PAE
 	default 2
@@ -1340,6 +1341,10 @@ config X86_PAE
 	  has the cost of more pagetable lookup overhead, and also
 	  consumes more pagetable space per process.
 
+config X86_5LEVEL
+	bool "Enable 5-level page tables support"
+	depends on X86_64
+
 config ARCH_PHYS_ADDR_T_64BIT
 	def_bool y
 	depends on X86_64 || X86_PAE
@@ -1698,6 +1703,7 @@ config X86_SMAP
 config X86_INTEL_MPX
 	prompt "Intel MPX (Memory Protection Extensions)"
 	def_bool n
+	depends on !X86_5LEVEL
 	depends on CPU_SUP_INTEL
 	---help---
 	  MPX provides hardware features that can be used in
-- 
2.10.2