x86/mm: Make virtual memory layout dynamic for CONFIG_X86_5LEVEL=y
We need to be able to adjust virtual memory layout at runtime to be able
to switch between 4- and 5-level paging at boot-time.
KASLR already has movable __VMALLOC_BASE, __VMEMMAP_BASE and __PAGE_OFFSET.
Let's re-use it.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180214111656.88514-4-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 63bf349..9225648 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1430,6 +1430,7 @@
config X86_5LEVEL
bool "Enable 5-level page tables support"
+ select DYNAMIC_MEMORY_LAYOUT
depends on X86_64
---help---
5-level paging enables access to larger address space:
@@ -2143,10 +2144,17 @@
Don't change this unless you know what you are doing.
+config DYNAMIC_MEMORY_LAYOUT
+ bool
+ ---help---
+ This option makes base addresses of vmalloc and vmemmap as well as
+ __PAGE_OFFSET movable during boot.
+
config RANDOMIZE_MEMORY
bool "Randomize the kernel memory sections"
depends on X86_64
depends on RANDOMIZE_BASE
+ select DYNAMIC_MEMORY_LAYOUT
default RANDOMIZE_BASE
---help---
Randomizes the base virtual address of kernel memory sections