x86/mm: Unify pgtable_l5_enabled usage in early boot code

Usually pgtable_l5_enabled is defined using cpu_feature_enabled().
cpu_feature_enabled() is not available in early boot code. We use
several different preprocessor tricks to get around it. It's messy.

Unify them all.

If cpu_feature_enabled() is not yet available, USE_EARLY_PGTABLE_L5 can
be defined before all includes. It makes pgtable_l5_enabled rely on
__pgtable_l5_enabled variable instead. This approach fits all early
users.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180518103528.59260-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 10 insertions, 3 deletions

diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index adb47552e6bb..c14a4116a693 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -22,12 +22,19 @@ typedef struct { pteval_t pte; } pte_t;
 
 #ifdef CONFIG_X86_5LEVEL
 extern unsigned int __pgtable_l5_enabled;
-#ifndef pgtable_l5_enabled
+
+#ifdef USE_EARLY_PGTABLE_L5
+/*
+ * cpu_feature_enabled() is not available in early boot code.
+ * Use variable instead.
+ */
+#define pgtable_l5_enabled __pgtable_l5_enabled
+#else
 #define pgtable_l5_enabled cpu_feature_enabled(X86_FEATURE_LA57)
-#endif
+#endif /* USE_EARLY_PGTABLE_L5 */
 #else
 #define pgtable_l5_enabled 0
-#endif
+#endif /* CONFIG_X86_5LEVEL */
 
 extern unsigned int pgdir_shift;
 extern unsigned int ptrs_per_p4d;