x86/mm: Adjust vmalloc base and size at boot-time

vmalloc area has different placement and size depending on paging mode.
Let's adjust it during early boot accodring to machine capability.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
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/20180214182542.69302-5-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/head64.c

@@ -51,7 +51,7 @@ EXPORT_SYMBOL(ptrs_per_p4d);
 #ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
 unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4;
 EXPORT_SYMBOL(page_offset_base);
-unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE;
+unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE_L4;
 EXPORT_SYMBOL(vmalloc_base);
 unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE;
 EXPORT_SYMBOL(vmemmap_base);
@@ -87,6 +87,7 @@ static void __head check_la57_support(unsigned long physaddr)
 	*fixup_int(&pgdir_shift, physaddr) = 48;
 	*fixup_int(&ptrs_per_p4d, physaddr) = 512;
 	*fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5;
+	*fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5;
 }
 #else
 static void __head check_la57_support(unsigned long physaddr) {}