Commit 6914f7e2 authored Mar 06, 2025 by Ingo Molnar

x86/mm: Define PTRS_PER_PMD for assembly code too



Andy reported the following build warning from head_32.S:

  In file included from arch/x86/kernel/head_32.S:29:
  arch/x86/include/asm/pgtable_32.h:59:5: error: "PTRS_PER_PMD" is not defined, evaluates to 0 [-Werror=undef]
       59 | #if PTRS_PER_PMD > 1

The reason is that on 2-level i386 paging the folded in PMD's
PTRS_PER_PMD constant is not defined in assembly headers,
only in generic MM C headers.

Instead of trying to fish out the definition from the generic
headers, just define it - it even has a comment for it already...

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/Z8oa8AUVyi2HWfo9@gmail.com

parent 3e385c0d

arch/x86/include/asm/pgtable-2level_types.h

+4 −4

Original line number	Diff line number	Diff line
		@@ -23,17 +23,17 @@ typedef union {
		#define ARCH_PAGE_TABLE_SYNC_MASK PGTBL_PMD_MODIFIED

		/*
		* traditional i386 two-level paging structure:
		* Traditional i386 two-level paging structure:
		*/

		#define PGDIR_SHIFT 22
		#define PTRS_PER_PGD 1024


		/*
		* the i386 is two-level, so we don't really have any
		* PMD directory physically.
		* The i386 is two-level, so we don't really have any
		* PMD directory physically:
		*/
		#define PTRS_PER_PMD 1

		#define PTRS_PER_PTE 1024