x86/mm: Replace compile-time checks for 5-level paging with runtime-time checks

This patch converts the of CONFIG_X86_5LEVEL check to runtime checks for
p4d folding.

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/20180214182542.69302-9-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/x86/power/hibernate_64.c b/arch/x86/power/hibernate_64.c
index 0ef5e5204968..74a532989308 100644
--- a/arch/x86/power/hibernate_64.c
+++ b/arch/x86/power/hibernate_64.c
@@ -50,7 +50,7 @@ static int set_up_temporary_text_mapping(pgd_t *pgd)
 {
         pmd_t *pmd;
         pud_t *pud;
-        p4d_t *p4d;
+        p4d_t *p4d = NULL;
 
         /*
          * The new mapping only has to cover the page containing the image
@@ -66,7 +66,7 @@ static int set_up_temporary_text_mapping(pgd_t *pgd)
          * tables used by the image kernel.
          */
 
-        if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
+        if (pgtable_l5_enabled) {
                 p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
                 if (!p4d)
                         return -ENOMEM;
@@ -84,7 +84,7 @@ static int set_up_temporary_text_mapping(pgd_t *pgd)
                 __pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC));
         set_pud(pud + pud_index(restore_jump_address),
                 __pud(__pa(pmd) | _KERNPG_TABLE));
-        if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
+        if (p4d) {
                 set_p4d(p4d + p4d_index(restore_jump_address), __p4d(__pa(pud) | _KERNPG_TABLE));
                 set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(p4d) | _KERNPG_TABLE));
         } else {